Untitled - HUBER

unistat control V3.8.1 

Contents 

1. 

V3.8.1 / 07.05 

Introduction .................................................................................................... 1 

2. General Information - Unistat Control ................................................................. 2 

2.1 Abbreviating keys............................................................................................ 3 

2.2 Display Information.......................................................................................... 3 

2.3 Fault .............................................................................................................. 3 

3. Physical Structure............................................................................................ 3 

3.1 Removing the Control Panel .............................................................................. 3 

3.2 remove unistat controller .................................................................................. 3 

3.3 Mounting the Unistat control............................................................................. 4 

3.4 Fuse change ................................................................................................... 4 

4. Control Panel .................................................................................................. 4 

4.1 Keypad .......................................................................................................... 4 

4.2 Actual value display......................................................................................... 4 

4.3 LCD window................................................................................................... 5 

4.4 Flow Diagram.................................................................................................. 5 

4.5 Signal Generator.............................................................................................. 5 

4.6 Remote Control ............................................................................................... 5 

5. Switch on....................................................................................................... 5 

6. Thermoregulation and Circulation....................................................................... 6 

6.1 Thermoregulation modes .................................................................................. 6 

6.1.1 Internal Control............................................................................................ 6 

6.1.2 External Control ........................................................................................... 7 

6.1.3 Other Temperature Control Methods............................................................... 7 

6.2 Switch on Circulation....................................................................................... 7 

6.3 Venting and Emptying ...................................................................................... 7 

6.4 No Fluid protection for Circulation Pump............................................................. 8 

6.5 Start Thermoregulation..................................................................................... 8 

6.6 Switching Off Thermoregulation ........................................................................ 9 

7. Altering Set Point ............................................................................................ 9 

7.1 Manual setting ................................................................................................ 9 

7.2 Set Point Ramp ............................................................................................... 9 

7.3 Thermoregulation Program .............................................................................. 10 

7.4 Change Set Point via Interface ........................................................................ 10 

7.4.1 „remote control„ ........................................................................................ 10 

7.4.2 TECON CONTROL ...................................................................................... 10 

7.4.3 4-20mA Analogue Interface (AIF)................................................................. 10 

7.5 Altering the set point via external control signal................................................. 10 

7.6 Set Point Tracking ......................................................................................... 10 

8. Safety Features............................................................................................. 10 

8.1 External Level Detector .................................................................................. 11 

8.2 Flow Detector ............................................................................................... 11 

8.3 Fault switches............................................................................................... 11 

8.4 Current Sensor / Power On Self-Test................................................................ 11 

8.5 Over Heating................................................................................................. 11 

8.6 Condensing Temperature Control..................................................................... 11 

8.7 Sensor Monitoring ......................................................................................... 12 

8.8 Circulation Safety Shut Down ......................................................................... 12


Contents 

8.9 Redundancy operation.................................................................................... 12 

8.10 Delta-T Monitoring ..................................................................................... 14 

9. Thermoregulation Programs ............................................................................ 14 

9.1 General ........................................................................................................ 14 

9.2 Program Descriptor ........................................................................................ 15 

9.3 Program Segments ........................................................................................ 15 

9.4 Approaching Starting Temperature................................................................... 16 

9.5 Running Tempering Programs.......................................................................... 16 

9.6 Ending A Thermoregulation Program ................................................................ 18 

9.7 Response to interruption of mains power .......................................................... 18 

Appendix A -- Program Directory.......................................................................... 19 

Program 0: Setting set point............................................................................... 19 

Program 1: Setting Of Minimum Set Point ............................................................ 19 

Program 2: Setting Of Maximum Set Point ........................................................... 20 

Program 3: Control Mode ................................................................................... 20 

Program 4: Second Set Point .............................................................................. 20 

Program 5: Mains Failure Automatic Function ....................................................... 21 

Program 6: POKO max....................................................................................... 21 

Program 7: POKO min........................................................................................ 21 

Program 8: POKO Programming .......................................................................... 21 

Program 9: ‘control parameters’.......................................................................... 23 

Program 10: Device Messages........................................................................... 24 

Program 11: Acknowledge Warning.................................................................... 25 

Program 12: Pt100 Correction (internal).............................................................. 25 

Program 13: Pt100 Correction (external) ............................................................. 25 

Program 14: Set Point Tracking ......................................................................... 25 

Program 16: Displaying Internal / External Actual Value in LCD .............................. 26 

Program 18: Delta–T–Limiter............................................................................. 26 

Program 19: Set Ramp Values ........................................................................... 26 

Program 20: Thermoregulation Program (TP) ....................................................... 28 

Program 21: Thermoregulation Program Parameters.............................................. 30 

Program 22: Thermoregulation Program Altering Run (during operation) .................. 30 

Program 23: Starting Thermoregulation Programs................................................. 30 

Program 24: Thermoregulation Processing Time ................................................... 31 

Program 25: Thermoregulation Program –Starting Date......................................... 31 

Program 26: Setting ‘TP track’ .......................................................................... 31 

Program 27: Time Base..................................................................................... 31 

Program 28: External Control-/release signal ........................................................ 32 

Program 29: Redundancy modes ........................................................................... 33 

Program 30: Setting date .................................................................................. 34 

Program 31: Setting The Time ........................................................................... 34 

Program 32: System Time Display...................................................................... 34 

Program 34: Air Venting Pause .......................................................................... 34 

Program 35: Compressor Automatic Controls ...................................................... 34 

Program 36: Activating Temperature for the HT................................................... 34 

Program 37: RS- Record Type............................................................................ 34 

Program 38: Time interval for RS Record ............................................................ 35 

Program 39: Separation Signs for RS Record Type 2 ............................................ 35 

Program 40: RS report on ................................................................................. 35 

Program 41: RS record off ................................................................................ 36 

Program 45: Watch–dog Function...................................................................... 36


Contents 

Program 46: Analogue interface – Control using current signal .............................. 37 

Program 47: Analogue Interface Monitoring........................................................... 37 

Program 49: Parameter limits.............................................................................. 37 

Program 51: Automation For The parameter ‘object mass’ ....................................... 37 

Program 52: Standard Parameter Set - Default..................................................... 38 

Program 55: Degassing..................................................................................... 40 

Program 56: ’Descaling’.................................................................................... 41 

Program 57: ‘Max cool power’ .......................................................................... 41 

Program 59: Compressor Clearance.................................................................... 41 

Program 68: Tempmove – flow temperature sensor.............................................. 41 

Program 69: Tempmove – reactor temperature sensor .......................................... 42 

Program 73: Advanced Control .......................................................................... 42 

Program 75: Fixed Cooling Power ...................................................................... 42 

Program 84: RS485 – Slave Address.................................................................. 42 

Program 85: Baud Rate for serial data transmission (RS232/485) ........................... 43 

Program 86: Selection RS232 ↔ RS485 ............................................................. 43 

Program 90: Language Selection ........................................................................ 43 

Program 93: Production number/serial number ..................................................... 43 

Program 94: Control Panel Identification ............................................................. 43 

Program 98: Version number ............................................................................. 43 

Program 106: Maximum Temperature Limit (for external Pt sensor control).............. 43 

Program 107: Minimum Temperature Limit (for external Pt sensor control) .............. 44 

Program 108: Maximum Temperature Limit (for internal Pt sensor control) .............. 44 

Program 109: Minimum Temperature Limit (for internal Pt sensor control) ............... 44 

Program 111: venting program ........................................................................... 44 

Program 116: Flow........................................................................................... 44 

Program 118: Delta-T Band Monitoring................................................................... 45 

Program 135: Analogue interface – calibrating of the AIF entry current.................... 45 

Program 136: Analogue Interface – calibrating of the AIF Exit Current Range ........... 46 

Program 137: Analogue Interface – Current/Temperature Relationship ..................... 46 

Program 138: Analogue interface – Assigning the exit signal .................................. 46 

Program 139: Analogue interface – Assignment Display......................................... 47 

Program 140: Analogue interface – Filter Constant................................................ 47 

Program 141: ‘Analogue Variable’ ....................................................................... 47 

Program 142: AIF-parameter-reset...................................................................... 47 

Program 143: „XL_CHARGE“ (UNISTAT XL only).................................................. 47 

Program 144: „XL-Power“ (UNISTAT XL only) ...................................................... 47 

Program 145: „XL – Vorhalt“ (UNISTAT XL only).................................................. 48 

Program 146: „XL – Starttemperaturdifferenz“ (UNISTAT XL only).......................... 48 

Program 147: „XL – Mode“ (UNISTAT XL only) .................................................... 48 

Program 148: „XL – Timer“ (UNISTAT XL only) .................................................... 48 

Program 149: „XL – Stoptemperaturdifferenz“ (UNISTAT XL only) .......................... 48 

Program 180: Heating Power Limiter ................................................................... 48 

Program 181: Cooling Power Limiter.................................................................... 48 

Appendix B -- Unit Messages .............................................................................. 49 

Appendix C -- PC/PLS data communication............................................................ 64 

Appendix D -- interface specification .................................................................... 65 

D.1. RS232 interface (on Plug Stv 12)................................................................. 66 

D.2. RS485 interface (on Plug Stv 12)................................................................. 66 

D.3. External Control Signal (‘release’, Plug Stv 5 at the unistat)............................. 66


Contents 

D.3.1 ‘OFF’........................................................................................................ 66 

D.3.2 ‘Pause / Stop’............................................................................................ 67 

D.3.2.1 A thermoregulation program is running: .................................................. 67 

D.3.2.2 Normal Thermoregulation:..................................................................... 67 

D.3.2.3 A control computer has taken over the control: ....................................... 67 

D.3.3 ‘Second Set Point Value’............................................................................. 67 

D.3.4 ‘Switch from Internal ↔External’ ................................................................. 67 

D.3.5 Analogue Port Tint ↔ Text.......................................................................... 67 

D.3.6 Stand by ................................................................................................... 67 

D.3.7 SP SWITCH............................................................................................... 68 

D.4. Potential (volt) Free Contact (POKO, plug connection Stv 4 at unistat).............. 68 

D.4.1 POKO ‘OFF’ .............................................................................................. 68 

D.4.2 POKO ‘actual value check’ .......................................................................... 68 

D.4.3 POKO ‘External Alarm’................................................................................ 68 

D.4.4 POKO ‘UNIPUMP/ PLS’ ............................................................................... 68 

D.4.5 POKO ‘TP spur [1]’..................................................................................... 69 

D.4.6 POKO ‘TP spur [2]’..................................................................................... 69 

D.4.7 POKO ‘Extern’ ........................................................................................... 69 

D.4.8 POKO ‘UNIPUMP with Echo’........................................................................ 69 

D.5. Analogue interface 4..20 mA....................................................................... 69 

D.6. Pt100 external........................................................................................... 70 

D.7. External level monitor ................................................................................. 71 

D.8. Plug Connection unistat control control unit........................................... 71 

D.9. Plug Connection unistat control unit ..................................................... 71 

Appendix E -- PP - command set for RS232 .......................................................... 72 

Appendix F -- LAI Command Set for RS485 .......................................................... 78

1. Introduction 


unistat control is the name for the electronic control system of the Huber unistats and 

Unichillers. It consists of the control electronics unit and a control panel (Picture 3), which 

can be used as a remote controller via an extension cable available as an optional extra. 

The following documentation enables quick familiarization with your unit: 

• The supplementary short version of the instructions together with the fold out page 

• These instructions 

• For reference and to get to know the valuable special functions, the appendix A-F at the 

back of these instructions. 

! To ensure safe use of the equipment these instructions should be read completely, 

at least once, prior to use. 

These instructions familiarise you with some new functions, which offers you a range of new 

properties: 

- Ease of control through prompts and clear display of important parameters. 

- Increasing operational safety due to constant monitoring of the control functions due to a 

control system which is independent of the electronic control system. Refer to the notes in 

paragraph „precautions„. 

LAI - The control unit offers a number of functions for the Laboratory Applications Interface 

software (Appendix C). 

- Calibrateable analogue interface 

- Serial interface RS232 or RS485 (selection optional) 

- Dry contact (just call it POKO) programmable for various functions. 

- Minimum and maximum set point can be pre set depending on the safety limits of the 

tempering liquid. 

- External control signal to trigger second set point other programmable functions. 

- Integrated controller for external tempering. 

- Continuous realization of the operating current principle for POKO and release signal. 

- Connection for external Pt100 sensor in 4-core arrangement (according to NAMUR 

recommendations) 

- Pt100 sensor calibration (Program 12 and 13) 

- Integrated programmer with calendar functions 

- 9 tempering programs with ca 270 segments can be stored 

- Tempering programs time and stable temperature programmable, repeat function. 

- External control signal and automatic mains failure function react with the programmer 

- Equipment shut-down is avoided, where low load operation is possible, by using different 

parameters. 

- Intelligent analyses of all sensor signals for assessment of machine status, with output of 

messages and warnings. 

- Automatic safety shut-down by major fault 

- Log of events for assessment of equipment performance. Important events will be shown 

with time and date. (Program 10). 

- fine tuning of the apparatus parameters for requirements of the automated application. 

Pre selection of heating or cooling capacity for the connection of external control circuits. 

(Program 44) 

- remote control and remote maintenance via PC interface possible (Appendix C) 

- As additional security installation you can use an adjustable level protection. 

Please take note of the information contained in „Safety Features„ 

1

News From Software Version 3.4: 


• External Pt 100 can be used to either monitor or control. 

• Delta-T-control protects the external glass reactor from thermal shock. (Program 18) 

• Compressor automation: 3 states available „ON„, „OFF„, „AUTOMATIC„ 

• In units with HT- coolers: The temperature at which the HT- cooler is switched on. 

(Program 36) 

• Additional POKO-Functions (Program 8). 

• Set point tracking/ Reactor lid thermoregulation (calorimetric) Program 14. 

• External control signal - additional functions (Program 28). 

• Analogue signal to set temperature instead of controller (Program 46). 

• Monitoring analogue signal (Program 47) 

• Selecting the temperature measurement source for control (Programs 68 und 69) 

• Heating/cooling power controlled via the digital Interface (Program 73). 

• Monitoring comparison of flow and reactor temperature (Programs 106 to 109). 

• Heating and cooling power limiting (Programs 180 and 181) 

2. General Information - Unistat Control 

The electronic unistat control used on the Huber unistats and Unichillers is universal 

throughout the range. It consists of two parts, the controller and control panel. Unistat 

control has an integrated cascade controller. Using an external Pt100 the application can be 

thermoregulated, wherever the sensor is placed. A level monitor can be installed for additional 

safety. 

The Unistat control is equipped with a non-volatile memory. The software used memorizes 

unit status data, which can be called up at a later date. An electronic clock makes a recording 

in chronological order possible. This makes it possible to activate the programmer at any 

selected date and time. 

The RS232 interface makes an event log of a process possible. The unit can be programmed 

so that the unistat control continuously sends values, unit status (status of the monitor, of 

potential free contacts, of the release signals) and the corresponding times and temperatures 

(can be transmitted with a resolution of 0.01K). 

Sensors have been installed to monitor and continuously analyze the unit. Temperatures, 

pressure, error conditions, electric voltages and currents are monitored. All actions are timed. 

The information obtained from the control unit are classified as follows: 

Messages inform, will be „blended in„ to monitor and record specific conditions (for example 

‘HEATLIMIT 50%‘). 

Warnings are stored and displayed to advise users of such conditions. Warnings must be 

acknowledged (program 11 Acknowledgement of warnings). 

Fault cause the mains cut off relay to isolate the circuits for the compressor, heating, pump 

and fans. This condition arises, if for example unreasonable high power consumption is 

measured for the current operating status. This condition will always be displayed. It is not 

reversible. This condition will be visually indicated by blinking in the actual value display and 

the LED’s in the flow diagram (Picture 1 see drawing at the last page). 

The controller is designed, so that specific settings will be locked during tempering. You get 

instructions via the LCD display. The changing of the minimum – maximum set points is only 

possible when the circulation is turned off. This avoids accidental adjustment of parameters. 

2

2.1 Abbreviating keys 


You often find the instruction in the text to press a key. The used abbreviation is always the 

„“ brackets. The instruction to press „0„ will look like this: 

Because of the danger of confusion the red key at the bottom of the controller (the 0-key) 

will be called in the instructions: 

is for the RAMP function, for ‘Set’ and so on. 

2.2 Display Information 

You can program the Unistat Control in one of three languages (German, English and French). 

Simple text that is understandable in all languages is displayed in one language. 

The display language is set using program 90. 

2.3 Fault 

Important occurrences are saved with date and hour in a long-term memory. With program 10 

and Appendix B incidents like Start/Stop of thermoregulation or any failure of unit can be 

interpreted. 

3. Physical Structure 

The control electronics of the unistat control is accommodated in a separate detachable 

housing. It is therefore possible to apply the valuable „Plug & Play“ philosophy which has 

been part of Huber equipment for many years. It is also possible to use it in the new 

generations of Unistats. Unistat control consists of two units: the electronic controller and 

the control panel placed in a recess in the housing. 

The control panel can be detached from the controller (a screw from above) and the 

electronic connection to the controller can be made with a special cable (Order No 6147). 

If the control panel is to be used via a cable connection, reference should be made to the 

paragraph ‘Remote Control’. 

3.1 Removing the Control Panel 

1) Turn off tempering and circulation by pressing key, turn off mains switch on 

unit. 

Switch off main switch on chillers 

2) Unplug from mains. 

3) Remove cover from fixing screw (picture 2 see drawing at the last page). 

For chillers: Remove the cover of plug connector (3 screws) directly behind control 

panel. 

4) Loosen M3 screw and remove. 

5) Tip control panel forward until mounting recess is released (ca 1 cm). Carefully pull the 

control panel up and out of its recess. 

3.2 remove unistat controller 

1) Follow all steps as explained in ‘remove control panel’. 

2) Loosen screw ‘fixing unistat controller’ (picture 2 see drawing at the last page) 

3) The housing is still connected to the unit via a plug connector. 

4) Pull housing vertically up. 

3

3.3 Mounting the Unistat control 


1) Check for proper pin alignment. 

2) Slide control box vertically down over the guide pins and fix into place with the screw. 

3.4 Fuse change 

1) Follow all steps as explained in ‘remove unistat controller’. 

2) Two fuses are placed in the back of the control housing (picture 4 see drawing at the 

last page) 

F1 (2A slow) circulation pump and fan 

F2 (0.2A slow) control electronics 

4. Control Panel 

Important information must be read carefully: 

The control panel is the central point for all information coming from and going to the 

thermostats, as well as for analogue control by the user, to the laboratory automation 

equipment, to the PC etc. Should the overview of the programmed functions be lost a 

parameter rest can be made using Program 52, which reverses everything back into initial 

status (factory setting). 

4.1 Keypad 

To comply with ingress protection requirements, the keypad and the display are covered with 

a protective film. 

The unit is equipped with seven rows of three keys. There are three keys in the bottom row 

to start the circulation pump and the thermoregulation (both green) and also the red 0-key. 

‘0’ is for ‘OFF’ (picture 1 see drawing at the last page). The row of keys above is for the 

programming of the unistat or Unichiller (function selection): 

Key < Set > starts the program selection 

Key < Ent > acknowledges the entered value 

Key < Esc > prematurely (without accepting the input) exits the program 

Ramp Function 

One row above are keys for the setting of the tempering program and to directly input the set 

values: 

< Ramp > a ramp in a segment or a set point ramp 

< Temp > desired end temperature of a segment or a set point temperature 

< Time > duration of a segment, or a check of the system time 

4.2 Actual value display 

See Program 3. 

The most striking and most important display is the green LED display indicating the actual 

value. Depending on the tempering mode the display shows a, 5 digit, temperature display of 

the internal or the external sensor (see picture 1 see drawing at the last page). A flashing 

display of the actual value indicates fault status. 

4

4.3 LCD window 


A numerical is not sufficient for this sophisticated unit. The illuminated LCD window contains 

the alpha/numeric display in two rows with 16 digits each row (picture 1 see drawing at the 

last page). 

4.4 Flow Diagram 

The flow diagram is situated in the top third of the control panel (picture 1 see drawing at the 

last page). It is the status display path of the thermostat liquid. The four green dots at the 

start, before and after the pump (LED 3,4,5,6 see drawing at the last page) are illuminated, if 

the pump is turned on. The yellow dot (Led 7), when the heater is turned on and the green 

dot bottom right (LED 8), when the cooling is on. Additionally the green dot (LED 10) shows 

the power is on to the compressor, above the green dot (LED 9) is for an activated HT chiller 

(if present). One of the two red dots, connected by a dotted line shows if internally (jacket 

thermoregulation, LED 2) or externally (controller / reactor thermoregulation, LED 1 in reactor 

symbol) controlled. 

4.5 Signal Generator 

The signal generator provides information of events that occur suddenly or due to a faulty 

operation. Characteristic sounds are for certain events. The signal is not loud enough to be 

used as a warning signal. The POKO (program 8) together with suitable externally acoustic 

device should be used for that purpose. 

4.6 Remote Control 

The control panel can, following the steps of ‘removal of control panel’ be removed from the 

unistat control and used via a cable connection. If the electric connection is interrupted, the 

unistat control will stop thermoregulation and an emergency shut down will result. 

Please switch off the thermostat in this case. 

5. Switch on 

After switching on the main switch, the control panel and the controller carry out an 

extensive self-diagnosis. A message will be displayed if anything unusual occurs. 

The important status information will be displayed as message. The following message could, 

for example, appear: 

The controller has been programmed for automatic switching on after the restoration of 

power, after failure of the main power supply. 

Automode: ein 

or 

Automode: on 

5 

or 

Automode: active 

Attention: one of these messages will appear depending on the language chosen (set with 

program 90). 

If you activate a function via the ‘external control signal’ (program 28), the following 

message will be displayed: 

Zweiter Sollwert 

or 

Second Set point 

or 

Consign 2


A tempering program can be initiated via the calendar. If a start date for Program 2 has been 

entered (Program 23), the following will be displayed when the equipment is switched on. 

Program start: 2 

27.11.01 5:15 

or 

Program start: 2 

27.11.01 5:15 

6 

or 

Départ progr.: 2 

27.11.01 5:15 

Also you will be informed of the status of the calendar and the clock. Information about the 

status (including date and time) of the unistat control can be recalled with the corresponding 

program functions at a later date. 

Generally the following applies: You will be informed if the general sequence is not disturbed, 

this information can be retrieved as an event log for a period of time. 

When the unit is ready to start, the following information is displayed: 

257 int 300max 

257.5°C -40min 

All temperatures are displayed in °C. 

For this representation it means: 

‘257.5 °C’ the set point in °C 

‘257 int’ the actual value, in this case measured with internal temperature sensor 

‘300max’ the maximum permitted set point 

‘-40min’ the minimal permitted set point 

Should there be an irregularity in the results of the initial self diagnosis, the following codes 

could appear together and are only possible after the mains switch on: 51/5, 51/29, 51/30, 

51/31, 51/35. Please check Appendix B for the meaning of these and other device messages. 

If it is attempted to start the circulation or thermoregulation immediately after, the circulation 

will not begin because the self-diagnoses has not been completed. During this the four green 

pump lights (LED 3, 4, 5, 6 see drawing at the last page) are flashing, these signal the call for 

circulation. 

6. Thermoregulation and Circulation 

6.1 Thermoregulation modes 

Program 3 can be used to switch between internal and external thermoregulation modes. 

6.1.1 Internal Control 

The internal thermoregulation uses a control loop to control the temperature at the internal 

Pt100-temperature sensor. This is called the „flow sensor„. It is built into the unit and is 

located near the discharge of the thermofluid (flow). Program 9 can be used to alter the 

parameters of the proportional–integral-controllers (PI-controller) 

Certain thermoregulation duties require different control methods to achieve best results. 

Set points can be supplied from various sources. Program 68 allows various alternatives.

6.1.2 External Control 


External thermoregulation uses an external Pt100-temperature sensor (Order No 6205 or 

6064) in conjunction with a cascade controller. The internal sensor in the flow is included in 

the control. This external method is used for the thermoregulation of jacketed systems. 

Certain thermoregulation duties require different control methods to achieve best results. 

Set points can be supplied from various sources. Program 69 allows various alternatives. 

Please pay attention to the following information. If the external sensors have not been 

supplied by Huber: 

- The external sensor must have a screened connection cable. This is to protect from static 

discharge and for ensuring accurate measurements. 

- If the sensor housing is made of metal, earth loops must be avoided. 

- The cable should not be unreasonably long. 

- Make sure the fixing of the external sensor at the place of measurement is satisfactory and 

a satisfactory heat transfer will be achieved. 

- The sensor must be well insulated to the screening or to the protective ground (R>20MΩ) 

6.1.3 Other Temperature Control Methods 

Certain, particularly specialized thermoregulation applications, it can be an advantage to 

bypass the integral temperature controller and control temperatures using different 

algorithms. Programs 73 and 75 are valuable tools for this purpose. 

6.2 Switch on Circulation 

To switch on circulation use the green key (bottom left on control panel). 

The separate switch for the pump is particularly useful to vent the system. 

This could be the reason why the flow sensor has not been activated. If the flow detector is 

not activated, the following message will appear. 

kein Umwälzdruck 

or 

no flow 

7 

or 

Aucun débit! 

If the unit has been filled it is important for safe functioning that the equipment been 

completely vented. Please read the information in the instructions for the UNISTAT models 

carefully. 

6.3 Venting and Emptying 

Venting of the unit can be achieved using intermittent pump operation. The gas can separate 

better during the pause phase and will be pushed out during pumping. 

The venting program, intermittent pumping is achieved by pressing the pump key (


Make sure that all possible isolation valves in the liquid circuit are open. Information about 

valves and the setting of these can be found in the corresponding instructions of the unistat 

model. Attention should be given to the following connections when using a unistat with an 

HT slider. The slide control can shut off the HT chiller or the evaporator, depending on the 

operating status. It is helpful for the venting if all slide control positions are opened to vent all 

components. 

The following procedures are suggested for emptying: 

1. Fluid temperature should be near room temperature. If you are using a viscous thermofluid 

at room temperature, it should be a bit warmer. 

2. Set ‘venting’ (press circulation key twice alternatively activate program 111) 

3. Drain the liquid 

4. Switch of the venting program. 

Attention: If the flow temperature is near room temperature after switch on, set the HT slide 

controls in a position in which no component is isolated. 

If a large external system or a viscous thermofluid is being used, the vent pause time might 

have to be extended (see program 34). To control circulation pressure: see program 116. 

6.4 No Fluid protection for Circulation Pump 

The circulation pumps are not to be used without a working fluid. To prevent damage 

resulting from this, there is a no fluid protection system for the circulation pump. If the 

condition ‘pump pressure ok’ does not appear within a few seconds after switching on, the 

pump shuts down automatically. The message ‘no fluid protection has been activated’ 

(60/45) is stored (see program 10 and paragraph ‘Safety precautions’). You can restart the 

pump using the circulation key , without having to switch off the system. 

The following information will appear on the LCD display: 

Pumpe trocken? 

Or 

Pump is dry? 

8 

Or 

Pompe sèche? 

This mechanism will remain activated until the status ‘pump pressure ok„ is sensed for the 

first time. If the pump pressure falls due to insufficient venting it is assumed that there is 

enough liquid present in the pump. 

The above message ‘Pump is dry?’ is acknowledged with . If you restart with the 

circulation key , the acknowledgement is not necessary. To control circulation 

pressure: see program 116. 

6.5 Start Thermoregulation 

The thermoregulation is started by pressing the key . The circulation is switched on. 

The message will be displayed once the correct circulation pressure has built up. 

Pumpentest 

in Ordnung 

or 

Check Pump 

OK 

Or 

Test Pompe 

En ordre 

The message ‘pump test’ is displayed again, if the circulation pressure does not build up 

thermoregulation is not possible.


If the flow detector is signaling circulation pressure although the pump has not started 

(probably due to a static column of thermofluid), the following 

message will appear: 

Druck ohne Pumpe 

or 

Pressure Failure 

9 

Or 

Press.saug pomp! 

The circulation pressure is constantly monitored while tempering is in operation. 

If the pressure should fall, the tempering will be switched off and the message ‘fault’ is 

displayed (see unit message 41/x in Appendix B). It is only possible to restart 

thermoregulation after turning the power off and back on. If this occurs during heating please 

consult program 55. 

In some models the chiller can be locked out due to a release signal not being present, 

especially after turning power back on. The corresponding message in displayed until 

clearance is given. The message informs that the minimum oil temperature is not reached yet 

inside the compressor and that it cannot be restarted. (see instructions of the unistat model) 

It is important that the compressor clearance being explained here is not confused with the 

external release signal, which is explained in Appendix D. 

Kühlma. Gesperrt 

or 

6.6 Switching Off Thermoregulation 

No Compr Clrance 

or 

Pause compress. 

To turn off the unit, press the key first. After that the controller can go back to the 

standby status. The circulation will stay on a few seconds to avoid heat build up, if the 

heating was in operation a short time before shut down. This can be stopped prematurely if 

the key is pressed again. The key should be used to protect the unit. 

The mains switch used only after the pump and the compressor have been switched off. 

7. Altering Set Point 

This paragraph introduces different methods of altering the set point and therefore the mode 

of thermoregulation. 

7.1 Manual setting 

See program 4 and 28, also Appendix C. 

The set point can be set by setting program 0 ( ) or with Hotkey 

. Reference should be made to the set point limits, which are values of the 

minimum and maximum set points. These are boundaries of the maximum and minimum set 

points allowed for this unit and are set by using programs 1 and 2. 

7.2 Set Point Ramp 

A ramp can be programmed, in place of a step change. This function is accessed by pressing 

key , or using program 19. The set point is set using the set point program 0, is 

depending on the selected mode of control (see program 3) and the internal and external 

Pt100 temperature sensor. 

A full description of this function is contained in the program directory (Appendix A) under 

program 19.

7.3 Thermoregulation Program 


Programs 20, 21, 22, 23 can be used to produce a tempering program (program 20), produce 

certain attributes (program 21), and start up (program 23). 

The process of a thermoregulation program can be altered using program 22. 

Consideration should be given to programmes 24, 25, 27 (see Appendix A). 

7.4 Change Set Point via Interface 

7.4.1 „remote control„ 

The possibilities for PC control via the interface are described in Appendix C. 

7.4.2 TECON CONTROL 

This mode of operation uses the properties of the TECON software (see Huber Catalogue). 

Please call the service Hotline for more information. (+49 781 9603 244) 

7.4.3 4-20mA Analogue Interface (AIF) 

The analogue interface is explained in Appendix D. The programs 137, 138, 139, 140 and 46 

are necessary for the use of AIF. Calibration is possible with programs 135/136. 

7.5 Altering the set point via external control signal 

The possibility of changing the set point via the external control signal is explained in 

Appendix D and program 28. The change over to the’2nd Set point ‘ is explained in 

program 4. 

7.6 Set Point Tracking 

The set point of the thermostat can be linked to the temperature of a measuring point using 

the external Pt100 temperature sensor and program 14. In this mode of operation, the 

thermostat follows a temperature to be supplied by another system. The calorimetric 

measurements can be used for lid thermoregulation (see program 14). 

8. Safety Features 

There are a number of safety features installed in unistats or Unichillers, which control the 

correct function and maintain the parameters, so that the process is safe. 

This can be important if the process is left unattended. This function can be important for 

over heat protection and level monitoring in external baths 

! Check the functioning of all safety features in short regular intervals. 

Information about checking the over heat protection is contained in the instructions for the 

unit. 

10

8.1 External Level Detector 


The level detector is installed in the open bath, to be thermoregulated. As soon as the level 

decreases significantly a dangerous condition exists (a leak?). The level detector connected to 

the unistat control passes this on and the unit will be switched off. 

For exact description see Appendix D. 

8.2 Flow Detector 

The flow detector monitors the circulation. If the circulation pressure falls during 

thermoregulation 

it will release an emergency shut down. (See message 41/X in Appendix B and program 55). 

8.3 Fault switches 

Depending on the UNISTAT model various sensors will be analysed. Messages inform about 

status (see program 10). 

8.4 Current Sensor / Power On Self-Test 

The current sensor is an important device especially for testing the functions of contactors, 

relays and heaters. 

By energising such components their function can be evaluated in comparison with the 

measured power input. 

8.5 Over Heating 

Every UNISTAT model is equipped with over heat protection, which operates independently 

form the unistat control. Only requires one sensor register excess temperature and the 

heating will be switched off immediately. A more comprehensive description is contained in 

the operating manual for the particular thermostat. 

Chillers without heaters do not have over heat protection. 

! The over heat protection should be triggered regularly, by setting the over heat 

protection set point temperature just above the present set point and then heat a little. 

Only a fully operational over heat protector will help to avoid damage! 

8.6 Condensing Temperature Control 

During thermoregulation the condensing temperature of the unit is constantly monitored. 

When the maximum value is reached the cooling power of the unit will be reduced, reduces 

the condenser heat rejection. This condition will be displayed as a message after a few 

seconds. The warning will remain, until it is acknowledged (see program 11, „acknowledge 

warning„). 

Kondens.Temp.! 

or 

Condens.Temp.! 

11 

or 

T°C condenseur


The condensing temperature can rise up to the maximum point, if the cooling power is very 

high and the cooling of the condenser is not adequate. 

Air-cooled units- an increased ambient temperature and/or dust on the condenser fins can be 

a cause. The sucking in of paper can be a possible cause. 

Water-cooled units- it is possible that the cooling water pressure is too low and /or the 

cooling water temperature too high. 

8.7 Sensor Monitoring 

The tempering will be stopped as soon as the status ‘sensor defect’ appears during tempering 

and the message 46/x will be recorded. (See Appendix B) 

8.8 Circulation Safety Shut Down 

During circulation only, the circulation will be shut down if the flow temperature exceeds the 

maximum set point of 10K. This is to avoid uncontrolled heating due to heat being introduced 

due to the circulation pump. (See unit message 49/x in Appendix B). The machine will switch 

off if the flow indicator has not registered any pump pressure for 20 min. 

In this case no message will be displayed. 

8.9 Redundancy operation 

A thermoregulation process can be continued despite a sudden loss of the master thermostat 

through the operation of a “cold” redundancy. For this, two thermostats are involved in the 

process. One thermostat, the “Redu Master” takes over the thermoregulation. 

While, the second thermostat, the “Redu slave”, stays in standby (switched on without 

thermoregulation and without circulation). In case of a disturbance of the “Redu Master” the 

“Redu slave” will switch on and takes over. This function is possible through a conjunction of 

the thermostats signals. The POKO signal of the “Redu Master” and the signal at the level 

connector of the “Redu slave” are being used for this purpose. The Redu master’s O.K. status 

corresponds to the POKO relay being energised (OK-energised principle). 

A cable (# 6589 ‘heat carrier unit’) connects the POKO of the “Redu Master” to the ‘Level’ of 

the “Redu slave”. This cable gives no return signal to the “Redu Master” so it cannot not 

know that the “Redu slave” is connected! 

The “Redu slave”, e g the unit which is held redundant, can distinguish the following 

conditions: 

1. “Redu slave” is not activated and the cable is not connected – this is the normal 

operating condition. 

2. “Redu slave” is not activated and the cable is connected – the equipment goes to error 

‘Level’ 42/1 or 42/x depending on the master unit’s POKO condition. A Level error is 

recognized. 

3. “Redu slave” is activated and the cable is not connected – the equipment deactivates 

its POKO and gives a signal to the display “REDU: Connect?” and to the signal 

generator. The slave cannot go to redundancy but does not go to error and keeps its 

actual operating mode. 

4. “Redu slave” is activated and the cable is connected – the “master” unit has an active 

POKO: this is the redundancy standby operation mode. 

12


5. “Redu slave” is activated and the cable is connected – the “master” unit has an 

active POKO: the slave thermoregulates with the preset parameters. 

The operation modes “Redu slave” and “Redu Master” are alternately displayed on the 

second line of the units display. The operation mode POKO master/POKO slave is set in 

programme 29 (Redundancy Modes). The “Redu Slave” starts to thermoregulate when the 

POKO of the “Redu Master” becomes inactive. 

This is the case when: 

1. The “Redu Master” is unpowered. 

2. The “Redu Master” is not ready yet after starting the equipment. 

3. The “Redu Master” goes to error 

Behaviour of the “Redu Slave” after activation: Once activated the “Redu slave” can only be 

deactivated manually via the keyboard. The mode “Redu Slave” has to be terminated through 

programme 29. The thermoregulation continues but can be terminated with the off key. 

Effect on the float switch: the same socket is used for both tasks. For this reason, the float 

switch is automatically cut off if the “Redu Slave” mode is activated. If the “Redu Slave” 

mode is deactivated and the equipment starts with the connected “Redu cable”, an error 

message “level error” will be displayed. 

Please note: using a second equipment to enhance the security of the installation is a 

complex process. The above mentioned functionality is helpful but never the less; it will not 

reach the target by itself. For example investigation of the behaviour of the fluid circuit and if 

the need of swing-type check valves or the set point on which the slave has to operate and 

which procedure will ensure that the slave is really going to be active in an emergency etc…; 

still has to be done. 

Important note: Please regularly make sure of the correct function of the redundancy 

operation before every thermoregulation process. 

13

8.10 Delta-T Monitoring 


Monitors are mechanisms made to protect the application or the process. Limit values are 

given to the monitor. If the limit value is reached, an action is carried out. The Delta-T 

monitor is independent of the temperature controller. Accordingly the Delta-T monitor reacts, 

if the delta-T limit value is reached with heating or cooling. 

The temperature difference between the flow and the process temperature in the “external “ 

tempering mode (ref. to program 3) is controlled. With program 118 the action as well as the 

limit value can be given. The default setting of the Delta-T monitor is given such that the limit 

value in the normal operation cannot be reached. 

9. Thermoregulation Programs 

9.1 General 

Unseat control is equipped with a programmer for the automated start and run of the 

thermoregulation programs. The connection of the programmer and controller makes a “fine 

tuning” of the unistat control possible. 

This refers to the programmable start time (program 23), the mains failure automation 

(program 5), the signalling via the potential free contact when the set temperature band is 

exceeded, the possibility to activate the POKO during a step of the tempering program 

(program 8) and the connection of an ‘external control signal’. 

14


Nine tempering programs with 30 program segments each are available. 

Each tempering program fundamentally consists of the program descriptor and up to 

30 program segments. The following settings prevailing at the start of processing a 

thermoregulation program will be adopted: 

Tempering method (internal or external), 

Minimum and maximum set points, 

Inclusion of external control signals, 

Use of potential free contact, 

Use of automatic response to main power failure. 

9.2 Program Descriptor 

When a tempering process is planned there is a particular path it has to follow the program is 

then set to follow this path exactly. The temperature ramps and temperature plateaux are 

only part of an automated process. Additionally the following data is required for the program 

descriptor at the start of the thermoregulation program. (See program 21). 

Start time for the thermoregulation program: 

The program start can take place immediately, or whenever you want. The setting for the 

start temperature for the first segment takes place in the program descriptor. 

A chosen ramp will start from the actual value to the starting temperature. If full power is 

required, a high value, for example 20 K/min, has to be set. 

Time or temperature stability for the tempering program: 

The rule for every program segment is: 

If the temperature at the end of the segment is to be checked the ‘temperature stability’ 

function should be selected. The next program segment will get started, when the actual 

value reaches the end temperature of the program segment with fixed accuracy (+/- 1K). 

If on completion of the segment time the actual temperature is not to be checked, the time 

stable option should be selected. 

If you work the tempering program with length ‘0’, details of the starting temperature, 

starting ramp, or if it the temperature stable option will be requested. The programmer can 

repeat the program segments. 

9.3 Program Segments 

Each program segment contains two values: The segment end temperature and the duration 

of the segment. The starting temperature of the segment results automatically form the end 

temperature of the previous segment. The duration of the segment is reduced constantly 

during the program run. The next set point is therefore determined from the difference of the 

end temperature and the actual value. At the end of a segment it will be checked, if 

‘temperature stability’ (See 9.2) has been requested the end temperature is to be reached 

with +/- 1K accuracy. If maintenance steps are necessary, the program run time of the 

program is extended. The waiting time in the actual segment will be displayed as tw in the 

LCD display. 

15

9.4 Approaching Starting Temperature 


At the time of starting the first ramp characteristics and the actual temperature are known – 

provided the circulation has already started. At this the point the time is calculated, that is 

needed to achieve the starting temperature for the first ramp. The time for this temperature 

change will be determined automatically. After each time period the next set point is given to 

the controller. Once the calculated time has passed, the temperature is checked, if the actual 

value achieved corresponds with the starting temperature at the required accuracy. (+/-1K ) 

If this is the case the first thermoregulation program segment will start. Otherwise the 

tempering will continue until the starting temperature is reached. 

In the event of mains failure: 

If the mains failure automatic feature was not activated the Unistat goes in to stand by, 

otherwise the start temperature will be achieved with the given gradient. 

9.5 Running Tempering Programs 

You will be informed during the whole run of the heating program via the LCD display. 

Immediately after the start (program 23) the following message might be displayed: 

or 

Startrampe! 

Nicht o.k.! 

Fehler: End-TMP 

Segment: 3 

or 

or 

Going Startramp 

Not OK! 

FAIL: End-TMP 

Segment: 3 

16 

or 

or 

T°C de départ 

incorrect(e) 

err. temp finale 

Segment: 3 

These messages let you know about conflicts between start temperature or end temperature 

(in segment 3) and the limits given by the minimum and maximum set points. After this has 

been corrected the same message can be repeated in a later segment. If this message comes 

up in segment 25, although your program only runs for 17 segments, set the stop point in 

segment 18 (see explanation for program 20). 

If no further conflict exists, the acknowledgement is displayed: 

or 

TP gestartet! 

TP: zeitstabil 

TP gestartet! 

TP: temp-stabil 

or 

or 

TP was started 

TP: time-stable 


TP: temp-stable 

or 

or 

TP actif 

Stabilité durée 

TP actif 

Stabilité T°C 

Set status time-or temperature stability before program start with program 21. 

If the ramp is approached, but the actual value is more than +/- 1K away from the starting 

temperature, following is displayed in the second line: 

Startrampe! 

or 

Going Startramp 

or 

Ramp départ


The start temperature is approached with the desired ramp (see program 21). 

The LCD display displays the following message during this time: 

22 int 

22.1°C ts 2.8 

The first line is the actual internal value, in the second line the given set point. ‘ts ’ is the 

required time, which the start ramp has still to run. The time ‘ts ‘ is given in minutes. 

The actual value should be the same as the start temperature if ts = 0. 

A waiting time tw is displayed if the difference is larger than +/-1K. In this time it is heated 

up to starting temperature. The following will be displayed if the difference between starting 

temperature and actual value is smaller than +/-1K: 

or 

TP gestartet! 

TP: temp-stabil 

TP gestartet! 

TP: zeitstabil 

or 

or 


TP: temp-stable 


TP: time-stable 

An indication for the next segment will follow (the first in this case): 

Nächstes TP- 

Segment 1/1 

or 

Next TP- 

Segment 1/1 

17 

or 

or 

or 

TP actif 

Stabilité T°C 

TP actif 

Stabilité durée 

TP prochain 

Segment 1/1 

The number before the oblique is the number of the tempering program, and the other is the 

segment number. 

The LCD display now displays the following message: 

21 int t p 212 

21.7°C t s 7.5 

21 int internal actual value 

21.7 °C Set point 

tp 212 remaining run time of the tempering program in minutes (or hours, see progr. 27) 

ts 7.1 remaining segment run time 

If ‘!!!’ appears with tp or ts , it is not possible to display the time (more than 54 hours). 

The program will still be run as normal. If the segment time is run out and the actual value is 

not the required end temperature (+/-1K), ts can appear in place of tw (waiting time). 

This condition can only be adjusted for the tempering program when the status is 

‘temperature stable’. At the status ‘time stable’ it will switch straight on to the next segment 

without regards to the actual value. Occasionally information will be provided about the 

current status of the tempering program and the given segment, so that the operator does 

not loose track of progress during a long program run.

9.6 Ending A Thermoregulation Program 


The possibilities of how a thermoregulation program, and how the thermoregulation is 

continued: 

• The thermoregulation program is given the status 'once'. Once the last segment of the 

thermoregulation program has been completed the thermoregulation will be stopped. 

• The thermoregulation program is interrupted with the key. The thermoregulation 

will be stopped. 

• The thermoregulation program is interrupted with program 22 option 9. The 

thermoregulation will be continued with the last set point. 

• The thermoregulation program is interrupted with a main power interruption: 

1. Mains failure automatic is not activated - the Unistat goes into standby mode. 

2. Mains failure automatic is activated – the thermoregulation program will be continued as 

described in 9.7. 

9.7 Response to interruption of mains power 

The unit will go into stand by if the mains failure automatic function was not activated. 

If activated, the started segment will be continued. Ramps will be continued – whereby the 

thermoregulation will be continued from the current actual temperature. 

The segment time will be reproduced with an accuracy of +/-10 minutes, the duration of the 

mains interruption will not be considered. 

18

Appendix A -- Program Directory 


Appendix A - Program Directory 

The setting of operating modes or unit parameters is carried out using programs. These are 

stored in an extensive memory in the control panel. Some programs only switch from one 

operating mode to an alternative (for example ‘control mode’ program 3), with others 

parameters have to be entered (for example ‘set point’ program 0) and some need a proper 

dialogue (for example ‘setting heating program’ program 20). 

The program selection is initiated by pressing , after that the program number must be 

entered, then press . A short description of the program appears on the LCD display 

unit together with a display of the current setting. 

Entering the numerical values for the parameters, for example the set point, is done via the 

number keys … , sometimes also by using the decimal point and the minus 

sign . The programming is confirmed by pressing . 

Corrections are possible by pressing . A programming mistake is stopped by pressing 

. Should a mistake be confirmed with , it can still be rectified by calling up the 

program and entering the new parameter. 

! Not every control panel is equipped with all programs! This depends on the software 

status! 

The software of the unistat control monitors logic discrepancies. A change of the minimum – 

maximum set point, for example, during activated circulation is not possible. If you try such 

change you will be warned (display ‘ Not allowed!’). The programmed change is rejected. 

Program 0: Setting set point 

After selection, ‘enter set point’ appears on LCD display. The set point is entered with 

to , and keys. The actual programming is done by pressing . The 

value of the set point is depending on the currently set minimum set point and maximum set 

point. The rule is: 

Minimal set point < = set point < = maximum set point. 

If this rule is not obeyed, an error message appears and the setting is ignored. The step size 

for the entry is 0.1K. You can choose to enter the second digit after the comma, by not 

pressing at the end, but by just entering another digit. With this you can reach a 

setting resolution of 0.01K. 

entering set point of 20.5 °C, 

(without !) setting a set 

point of 20.55°C. 

The activation of this program is achieved by pressing , this is the 

same as pressing the Hotkey . 

Program 1: Setting Of Minimum Set Point 

After selection, the program name appears and the current minimum set point appears. 

The value is entered by pressing keys … and . Only whole numbers are 

possible, no digits after comma. The entering is done by pressing . The value of the 

minimum set point is depending on the current set point and the unit parameters 

(Lowest permissible temperature). The rule is: 

Lowest permissible temperature < = minimum set point < = set point. 

If this rule is broken, an error message appears, and the setting is ignored. 

19



This program can not be run if the circulation is activated. 

Program 2: Setting Of Maximum Set Point 

After selection the program name and the current maximum set point appear. The value is 

entered using the … and keys. Only whole values are possible, no digits 

after the coma. Values are entered using the key. The range of values for the 

maximum set points are dependent on the current set point and the unit parameters (highest 

permissible temperature). The rule is: 

Largest permissible temperature > = Maximum set point > = Set point 

If this rule is broken, an error message appears and the entry is ignored. 

This program cannot be run when the circulation is activated. 

Program 3: Control Mode 

After selection of the program, this message appears 

Tempmode:INTERN 

INT: EXT: 

or 

Change Reg-Mode 

20 

or 

Changer rég. T°C 

The control mode will be switched from internal to external in this case through pressing of 

key . This results in the actual value for controlling the temperature being obtained from 

the externally connected sensor. 

! If you choose the external tempering without an externally connected sensor, an 

actual value of –151.1°C is displayed. As soon as the operator attempts to start 

heating with this, the unit will switch off with the fault code 46/2 (External sensor 

defect). This condition can only be rectified by switching the unit off at the main 

switch. 

The set status is identified from the red LED flow chart (fold out picture: LED1 for external 

LED2 for internal control). 

Please note: 

The internal heating method controls up to the set temperature with help of a sensor. 

This sensor is the (internal) flow temperature sensor, which is installed immediately prior to 

the discharge of the thermofluid. The external tempering method controls with help of two 

sensors. Additionally a ‘PT 100 external’ is used with the unistat control. 

A cascade controller is used for this method. This means the external actual value is used to 

calculate a variable set point for the internal control. (Note paragraph 6.2.4 and program 14). 

Program 4: Second Set Point 

The setting of the second (alternative) set point is analogous to the input of the ‘set point’ in 

program 0. This set point is activated with function ‘external control signal’ (see program 28) 

or via a watchdog event.



Program 5: Mains Failure Automatic Function 

After mains failure the unistat or Unichiller goes on working with the same parameters as 

before. Should there be a main power failure during tempering, the usual self diagnosis tests 

are run on start up after restoration of the mains supply. The set tempering is restarted if no 

error is present. If this happens during the run of a tempering program (see program 20), it 

will continue. 

Program 6: POKO max 

This is only relevant for set option ‘actual value check’ in program 8. Setting of the upper 

temperature level for the potential free contact (POKO) in 0.1K steps relative to the set point: 

An entry of 1.5 in this program means, that the POKO stays activated until the actual value is 

1.5K above the set point. Factory setting: 1.0K. 

Program 7: POKO min 

This is only relevant for set option ‘actual value check’ in program 8. Setting of the lower 

temperature level for the potential free contact (POKO) in 0.1K steps relative to the set point: 

An entry of 1.5 in this program means, that the POKO stays activated until the actual value is 

1.5K below the set point. Default setting: 1.0K 

Program 8: POKO Programming 

There is a range of programming options for the POKO. Pressing the key allows the 

operator to browse through the different possibilities. You will find the technical data of the 

POKO in appendix D. Important: The OK – status always means the contact is normally 

closed. 

(0) POKO Function ‘OFF’ 

The POKO displays the OK – status when the unit is ready to operate. This condition 

is after the internal controller check, ca 30sec after the switch on. The OK – status 

will be ended by switching off the mains or a fault. 

(1) POKO Function ‘Actual Value’ 

Using the program 6 and 7 you can set the upper and lower limit of the temperature 

range around the set point. 

The potential free contact displays the status, that the set point and the actual value 

differ relative to a pre set temperature range. If the range is exceeded the potential 

free contact is switched (away from OK – status), nor will further reactions of the 

unistat or Unichiller will take place. If the actual value is in the range, the contact will 

be re set in OK – status. 

Example: The ‘actual value check’ has been activated. (External control mode). 

Using Program 7 ‘POKO max’ a limit of 5K is set and with program 6 ‘POKO min’ 7K 

given. The set point is at the moment at 27,5°C. The contact will switch the OK 

status off as soon as the external sensor measures more than 32.5°C or less than 

20.5°C. It depends on the tempering method set in program 3 whether the external or 

the internal sensor is used. 

21

(2) POKO function ‘external alarm’ 



The POKO relay is only activated (OK status) in this function, if the unit is in ‘fault 

status’ when it is switched on. This is so that the alarm is not raised when the unit 

gets switched off. If you wish the alarm function together with the work flow 

principle, please use the POKO function ‘OFF’. 

(3) POKO function ‘UNIPUMP/ PLS’ 

UNIPUMP: This POKO function is used to connect the signal calling for the circulation 

pump to start with an external booster pump. This has to be done so that the external 

pump runs in synchronisation with the circulation pump in the unit, this means that 

the POKO goes into OK status as soon as the circulation pump starts. 

PLS: PLS stands for „Prozess Leitsystem“ (English-Process Control System), this mode is 

often used when the unistat is integrated in a „PLS“. 

An example of this would be when the unistat would be controlled via a „PLS“ via the 

external control signal (Program 28 Option 5), the POKO can also be used to communicate 

the status of the unistat to the PLS. 

Condition POKO ON means thermoregulation is activated. 

Condition POKO OFF means thermoregulation is not activated. 

(4) POKO function ‘TP spur [1]’ (tracking) 

This function only switches the POKO into the OK status if thermoregulation program 

is running (to be set via program 20, to be started with program 23) and the tempering 

program segment chosen with program 26 is run, by requesting the POKO to be 

activated. 

(5) POKO function ‘TP spur [2]’ (tracking) 

As explained in function ‘TP spur [1]’, but the POKO stays activated (OK status) for 

the rest of the thermoregulation program. 

Please note: The POKO function can, if required, be re programmed while the 

thermoregulation program is running. 

(6) POKO function ‘set via RS232’ 

The POKO can be turned on and off via the serial interface. 

Use: PC software UNISTAT PROGRAMMER from version 2. 

(7) POKO function ‘test extern’ 

An actual value check for the EXTERNAL SENSOR, only when this is not the control 

sensor. A temperature range monitoring is taking place, as explained in option 

ACTUAL VALUE CHECK. The limits are used which are set using program 6 and 7. 

Limiting of option ACTUAL VALUE CHECK: Using EXTERNAL tempering method, both 

functions are identical, with INTERAL control mode is the ACTUAL VALUE CHECK 

only related to the internal sensor, TEST TEXTERN to the external sensor. This enables 

a temperature to be monitored which has no connection to the thermoregulation 

process. 

22



(8) POKO Function „UNIPUMP with level monitoring" 

This function is used to monitor if the “UNIPUMP” being controlled by the POKO is 

operating in synchronisation with the Unistat pump. The operating status of the 

“UNIPUMP” is signalled via a contact to the “Level” socket on the Unistat Control. 

By non-synchronised operation a fault signal will be generated. This function is 

particularly important when the status of the “UNIPUMP” is to be monitored. 

Program 9: ‘control parameters’ 

! Beware: To adjust these functions, a basic knowledge of a PI-/PID- control theory is 

required! The appropriate literature should be consulted. Generally, reasonable results 

can be obtained using the set parameters for both internal and external control. There 

are two control variations. The older (standard) variation uses a pair of variable P and I 

and summarises into the so called ‘object mass’. The variant makes it possible to set a 

proportional band (in K), before time (in s) and after set time (in s). Both variants have 

in common that the parameter sets for internal and external controlling can be set 

separately. 

STANDARD – variations: 

The so called ‘object mass’ is a variable, which is a numerical value from 0 to 15. 

There are two different object mass settings, i.e. internal and external. These can be changed 

using program 9. This value adjusts the controller parameters for thermoregulation. As 

standard the value 5 is used. It might be necessary to set different parameters. 

The following list indicates, what effects the ‘object mass’ has on the internal control sizes 

‘P’ and ‘I’ (the amplification factors for the proportional and the integral part of the 

controller). Please note that it is possible with the ‘object mass’ =15, to set the values for 

‘P’ and ‘I’ independent of each other. Program 51 offers the possibility to make the parameter 

search easier! 

At set ‘object mass’ 15: 

The values of ‘P’ range from 0 to 31. A 0 means, that the proportional part (proportional 

value) of the controller is small, but not completely switched off. Increasing ‘P’ means that 

the proportional part of the controller is having more influence. ‘P’ is an approximate 

measurement for the ‘Proportional band’, used in conventional controller philosophies. 

Note; The bigger the P value, the smaller the proportional band. 

The value range for ‘I’ ranges from 0 to 127. A 0 means is this case, the integral part 

(integral value) of the controller is completely inactive, so the ‘PI’ controller turned into a 

simple ‘P’ controller. Increasing ‘I’ the integral part of the controller, the ‘I’ has more 

influence. ‘I’ is inversely proportionally to the value used for the integral time in other 

controller philosophies. 

The following table is for the external thermoregulation: 

Object mass: 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 

‘P’-Element 1 1 1 1 2 2 2 2 3 3 3 3 4 4 4 

‘I’-Element 1 2 3 4 1 2 3 4 1 2 3 4 1 2 3 

Usually good results can be achieved with ‘object mass 15’ (P=4, I=8), for external 

thermoregulation. 

23



A ‘recipe’ to find the fitting control parameters quickly, for external thermoregulation: 

• Set ‘object mass 15’, choose P=0 and I=0. Do a step change to the set value (for 

example from +20°C to +40°C) in the desired temperature range, and monitor the 

resulting temperature. As soon as the set value is reached. Set a step change back 

(+40°C to +20°C) and monitor the system reaction. 

• Try this experiment with P=1 and I=0, then with P=2 and I=0 and so on, until a so 

called ‘over shoot’ occurs for the first time. 

without overshoot with overshoot 

• Reduce P by 2 steps (for example over shoot from P=6, therefore continue with P=4) 

and increased ‘I’ until the desired controller behaviour is achieved. ‘I’ can be enlarged 

three steps at a time. 

• A compromise between control accuracy, slight over shoot and reaction speed in reaching 

the set point is sought. 

The following table is for the internal thermoregulation: 

Object mass: 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 

‘P’-Element 2 2 2 2 2 2 3 3 3 3 4 4 4 4 4 

‘I’-Element 1 2 3 4 5 10 2 4 5 10 1 2 3 4 5 

Usually good results can be achieved with ‘object mass 5’ (P=2, I=10), for internal 

tempering method. 

In Short: The so called ‘object mass’ is nothing other than an assignment of a number 

between 0 to 14 to a pair of controller parameters ‘P’ and ‘I’. The ‘object mass’ 

15 makes of ‘P’ and ‘I’ possible, within a given value range. 

PID-Controller variant 

Information provided on request. 

Program 10: Device Messages 

One unit message with date and time is displayed at a time. The newest message overwrites 

the oldest message. The next, older message appears after pressing . To scroll 

through the messages the keys are used. To leave this program press . If a 

message can not be analysed, the message ‘F!’ appears additionally. 

With this program it is possible to find the cause of certain unit conditions, even if the unit 

has been unattended for some time. 

The unit message is structured as follows: e.g. 46/2 

'46' is the Code 

'2' is the Index 

There are three kinds of unit messages: 

General message for example 1/x or 2/x 

Warning for example 60/45 or 20/x 

Error for example 41/6. 

A list of the relevant unit messages with code index is in Appendix B. 

24

An example for the display: 

28.01.01 9:23 

Meldg.: 46/2 



This would mean for example, that on the 28.01.01 at 9.23 using the selected external 

control mode, the external temperature sensor suffered a defect or noticed to be missing. The 

code 46 is an error, leading to the switching off of the unit. 

In the event that a service call has to be placed after a defect, the process can be accelerated 

by reading and noting the last 10 messages with date and time from the memory. If these 

messages communicated during the service call, we can possibly start the first steps to 

resolving the problem. 

Program 11: Acknowledge Warning 

The appearance of a warning, which does not cause the unit to switch off, is acknowledged. 

If more than one warning has been triggered, the most important one is delivered first 

enabling the highest priority to be acknowledged first. 

Program 12: Pt100 Correction (internal) 

With this program it is possible to adjust the actual value of the internal Pt100 temperature 

sensor, in the range of +/- 5K. 

If program 12 is called up, the current correction value (Standard: 0) appears. You leave the 

program without changing anything by pressing . If you enter a value bigger or 

smaller than 5K, the following message appears: 

Nicht zulässig 

or 

Fct not Accepted 

25 

or 

Non autorisé. 

The entry is made by using a resolution of 0.1K. (0.01K can be entered instead of .) 

This is for following relation: 

Requested value = Pt measured value + correction value 

Example: 

(Correction value was set at 0) 

Display value: 23.5°C 

Required value: 22.9°C Correction value: -0.6K 

Note: The correction value is not lost at mains switch off. With program 52 – standard 

parameter set – it is set back to the standard value of 0. 

Program 13: Pt100 Correction (external) 

The correction value for a connected Pt100 external temperature sensor in 4-core 

configuration. 

As program 12 but for an external sensor. The connection configuration (connector and plug) 

all correspond to the NAMUR guidelines, and are to be found in Appendix D. 

Program 14: Set Point Tracking 

The given set point is executed via the external Pt100 temperature sensor. This means: If the 

external sensor measures 15°C, the set point will be set to 15°C. If requested you can set 

an offset into the externally measured value with program 13. 

This mode is rejected if the set point is given through a different source (e.g. a ramp or 

tempering program is activated, external tempering stopped (program 3), or the analogue 

interface (‘AIF’) activated with program 46).



Application Example: Tracking of temperature of a jacketed reactor lid, to avoid heat transfer 

through the lid. 

Program 16: Displaying Internal / External Actual Value in LCD 

Normally the internal actual value is displayed on the top left of the LCD display, with internal 

control. This might not be necessary. In this case it is possible with this program, to display 

the actual external temperature value on the LCD, when the internal tempering method has 

been selected. 

Beware: If you set this option but do not have an external sensor connected, it can lead to an 

error value of –151,1 on the display. This setting only works in connection with the internal 

tempering method. 

Program 18: Delta–T–Limiter 

With this program a maximum allowed temperature difference between internal and external 

actual value when operating in external control mode. When the selected temperature 

difference is achieved, the power of the Unistat is reduced so as the difference is not 

exceeded. 

Program 19: Set Ramp Values 

The activating of this program by pressing is the same as 

pressing the Hotkey ! 

Instead of a step change, a set ramp value can be programmed. The set point values are 

entered similarly to those in the set value via program 0 (key 'Temp'), depending on the set 

tempering method (see program 3), on the internal or external Pt100 temperature sensor. 

go K/min 

?? 

If you chose as time base ‘hour’ (program 27), the following is displayed 

go K/h 

?? 

Two of the three ramp parameters must be set: 

1? The gradient of the ramp. It is set, by how much K/min or K/h the 

temperature has to change after the ramp start. The entry of a negative value 

means decreasing temperature. 

2? Setting of end temperature of ramp in °C, so the actual value, which is to be 

reached at the end of ramp function. 

3? Setting of time in min (depending on setting of program 27), set the duration of 

the ramp. 

Before the ramp function can be executed, it is checked to insure the minimum or maximum 

set point have not been exceeded. This would lead to the rejection of the ramp parameters. 

Note: Two parameters are needed, to define a ramp. If a third parameter was entered, 

it would result in either the same values as it would with two, so it would be unnecessary, or 

it would contradict the other two. 

26



The result is calculated from the following relationship: 

- current actual value 

= ------------------------------------------ 

 

For which the current actual value is a constant. 

For example: The tempering is running at 20°C. Requested is a set ramp of +0.4K/min up to 

an end temperature of 73.5°C 

20 int 85 max 

20.0°C 5 min 

enter (or start program 19): 

go K/min 

?? 

And then for the raising. The display 

indicates: 

go K/min 

R:0.4 

The ramp is displayed and bottom right is a note of one of the missing entry 

values ‘T’ for temperature and ‘t’ for time. 

 

go K/min 

Temp: 73.5 

The ramp is started and the following is displayed on the LCD: 

22 int 85 max 

47.3°C tR 15.5 

32,7°C is the given ramp, tR = 15.5 min is the remaining time, which the ramp has still to 

run. During this time the gradient of the ramp and the end temperature can be observed if 

key is pressed. 

go K/min 

R: 0.4 T: 73.5 

Note: The ramp function is only operable during thermoregulation. The aborting of the ramp is 

possible via entering new set points via program 0. 

27



Program 20: Thermoregulation Program (TP) 

With this a program can be edited or created. 

It is only possible to execute this program if no other tempering program is activated. Only 

one segment of the tempering program may be worked on at a time. A segment consists of 

end temperature to be targeted, and the time in which it is to be reached. 

The starting temperature of a segment is the end temperature of the previous segment. As 

the first segment has not got a predecessor, the ‘start temperature’ must be set. If a 

constant temperature is to be maintained in a segment, the end temperature of this segment 

should be the same as that of the previous segment. 

After program 20 has been selected, the duration of the segment appears in the second line 

of the LCD display. 

TP Wahl: 

1:7 2:0 3:18 

In this example program 3 has eighteen segments. 

The program number is selected. If the number of segments is 0 (in the example program 2), 

a new program is being prepared. The starting temperature of the ramp, and other entries 

(program 21) are required. The following appears: 

Start-Tmp wählen 

The entry must be made in one of the following forms: 

-39.8 or 100 or –0.2 

After confirming the entry with you are requested to enter the ‘starting ramp’. With 

this it is selected which gradient the starting temperature is to be targeted from the current 

actual value at the time of the program start. The entry is to be made directly in the unit 

K/min. After the acknowledgement with the programmer is now in the segment 

processing phase. 

Select a program with a length not equal to zero (here for example TP3), the programmer is 

straight into the segment processing phase: 

Segm Wahl:1 bis 

18: 

After the entry of the number within the permitted range the segment displayed in the 

following way: 

Ssssss eeeeee°C 

N:nn rrrrr ttttE 

That means: 

‘N’ Program number 

‘nn’ activated segment 

‘ssssss’ starting temperature including prefix and decimal point in °C 

‘eeeeee’ End temperature including the prefix and decimal point in °C 

‘tttt’ Time duration of this segment 

‘E’ Unit of the time (‘m’ or ‘h’ for minutes or hours, program 27) 

28



‘rrrrr’ gradient of the ramp in k/min or k/h 

The gradient of the ramp is made up of the quotient of the temperature difference and the 

segment duration and the unit K/h or K/min, depending on given ‘E’. 

To process the segment parameters there is a choice between , and 

, with and the parameters are set directly, using the 

segment parameters are set using algebraic calculations. 

requests the entry of the end temperature of the segment. This will be compared 

to the unit parameters for minimum and maximum set point. (See program 1 and 

2) The value will be rejected if the limit is exceeded. The resolution is 0,1K. 

determines the segment duration in a pre determined unit, minute or hour. The 

time-set range is per segment 0.1to 3240 min (54 h). 

sets the gradient of the ramp in the segment. After setting this question appears: 

Fixieren: 

End-temp? Time? 

After pressing , the time will be set. The new end temperature will be determined by 

the ramp that is to be set. The same goes for the fixing of the end temperature when using 

. Then the display of the step with changed values for tttt, eeeeee and rrrr will 

appear. If unrealistic values for the ramp are entered, the ‘?????’display will appear for the 

gradient of the ramp. The result of the entry is 0.1 K/min or 0.1 K/h. Please note that a small 

difference between displayed and entered values are possible due to rounding up or down 

errors. The entered ramp value is only accepted, if the ranges for the unit temperature range 

and the segment duration are not exceeded. 

Scrolling Through The Program Segments: 

Pressing a segment is switched forward and with backwards. 

The programmer must be in the command setting mode to do this, where the keys ‘Ramp’, 

’Temp’ and ‘Time’ are to be used. 

Naturally the segment number must be within the limits for the smallest and largest segment 

number. 

If the message ‘sgmt. Activated’, that means that the program length has been extended by 

one segment. In this segment the values are shown, which was previously set. 

With the previous segment can be called up. 

With the segment number can be set. 

Before the segment is set a test is run, to check if the entries of the previous segment 

contain only valid values. If not, this segment will be initialised and displayed. 

If all entries are complete, leave the program 20 with . 

Setting program length: 

You have for example 20 segments, but only want to run the first three segments you can 

set a ‘stop marker’ at the fourth segment. This is done by pressing for the segment 

duration and confirmed with . 

Stopmarke 

or 

stop marker 

29 

or 

Repère stop



After this the program only has 3 segments. 

Later the old data for ‘time’ and ‘end temperature’ of the following segments can be used, to 

complete the tempering program. At the last segment an additional segment can be added by 

pressing the key. If a segment is selected using the function, the program 

changes accordingly. 

Program 21: Thermoregulation Program Parameters 

An existing tempering program is recalled. Step by step changes are possible after that (to go 

on press ): 

• Changing of starting temperature 

• Correction of start or gradient of the ramp in K/min or K/h 

• Choosing ‘time -/temperature stability’ 

• ‘one’ or ‘endless’: The chosen tempering program is either once or repeatedly processed. 

(Note the information relating to program 22) 

In each of these 4 blocks the operator is required to enter information. Use only , to 

leave the block, without changing the value. The current status will be displayed in block 3. 

If the display shows ‘time stability’ the status can be changed to 'temperature stability' using 

. 

Program 22: Thermoregulation Program Altering Run (during operation) 

With program function 22 the run of the program can be altered while it is being processed. 

After selection, a program a list appears: 

STOP GO 

TP-E SEG-E . 

If is selected, the program is stopped completely. After that the thermoregulation 

remains at the current set point value. Please note that the set point value can be changed 

while the program is activated. This is a different way of stopping the program, other than 

using the key. By pressing key it is possible to change into the next program 

segment immediately. 

The program can be stopped at the current point by using key . Key 

is used to cancel key , the program continues. The same results with key and 

can be achieved when using program 28 via the external control signal (see 6.2). 

Program 23: Starting Thermoregulation Programs 

After choosing program number which is selected by using to scroll through, and the 

request to start 

Start jetzt: Ent 

später: Time 

or 

Start Now: 

Later: 

30 

or 

Dép. imméd: 

Retardé: 

A program can be started straight away or prepared for an automated start. Please note that 

no more than one program can be activated at the same time. 

Important: 

1. The program is started in the control mode (internal/external), which was pre set at the 

starting point.



2. At the starting point all temperatures which are in the tempering program are compared 

with the minimum and maximum set point value at the starting time. The start will be 

prevented if there are any temperatures exceeding the limits. If a calendar start is planned, 

the program should be checked before hand to insure that there are no discrepancies (for 

example through an ‘immediate start’). The test can be broken off after the check by 

pressing . 

3. It is recommended to start the tempering and wait until the temperature has stabilised. 

After that the start of the chosen tempering programs follows 

The indication: 

TP-Vorbereitung 

or 

TP-prepare! 

Indicates that the preparation of the program is not completed. 

31 

or 

TP-prepare 

Program 24: Thermoregulation Processing Time 

After a program number has been selected it can be viewed, when the program was created, 

date & time, and when the last changes were made. The set starting time for the tempering 

program (or ‘no’, if no starting time has been set) can also be viewed. 

Program 25: Thermoregulation Program –Starting Date 

If a start date exists for the program the date is displayed with the number of the tempering 

program. A starting date that is in the past will be deleted. 

Program 26: Setting ‘TP track’ 

A segment of any program can be selected at which the POKO is activated - the so called 

‘track’. The following procedures are possible: 

1. A thermoregulation program TP7 with 17 segments has been written 

2. Because a switch is necessary in segment 5 a marker is set in segment 5 with program 

26 in TP7. 

3. Set the POKO in function ‘Tp-Spur1’ or ‘Tp-spur2’ (see program 8). The POKO is not 

active, so not in ok status. 

4. Start tempering program TP7. 

5. When segment 5 is reached the POKO switches into the ok status (active). 

6. When segment 5 is left the POKO switches back if Tp-Spur1 was chosen, otherwise it 

switches back at the end of the program. 

The time the POKO is switched on in active Tp-Spur1, is determined by the segment time. 

This way it is possible to vary the length of this signal. If the POKO is to be switched only as 

part of a ramp or of a temperature plateau, a ramp or a temperature plateau can be split into 

2 segments without any problem. 

Program 27: Time Base 

In connection with making or changing a tempering program time dependent parameters in 

minutes (‘min’) or hours (‘h’) are displayed. This unit relates to all the time related processes 

in the segments of a tempering program (program 20 and others). This message is displayed 

on request: 

Zeitbasis Minute 

min:Std: 

or 

Time base minute 

min:hour: 

or 

Base temps heure 

Minheure



Please note that a program with short times and fast ramps should be displayed with time 

base minute, as the minimum resolution in hours would be 0.1 hour (6 min) is not displayed 

at its optimum. 

Program 28: External Control-/release signal 

This entry of the unistat control is usually found on the back of the thermostat in the form of 

a three pin connector (for specification see Appendix D). This program is used to dictate in 

the sequence in which the external control signal is activated. After choosing the program a 

message about the current status appears, other possibilities can be viewed by scrolling using 

the key or by reaching the desired function and keying in the corresponding number: 

Weiter: 

Aus 

or 

continue: 

OFF 

Activating of the release signal is of no consequence. 

After pressing : 

weiter: 

PAUSE/StOP 

or 

continue: 

PAUSE/StOP 

32 

Or 

or 

continue: 

eint 

continue: 

PAUSE/StOP 

Requirement: The tempering was already started with the green thermoregulation key Iϑ. 

Deactivating the release signal stopped the tempering, activating will restart it. 

After pressing of 

weiter: 

2ter Sollwert 

or 

continue: 

Second Setpoint 

or 

continue: 

2e val. nomin 

Protection Function: As long as the release signal is present thermoregulation will continue 

normally. If the release signal is not present, the thermoregulation will control to the second 

set point. If the release signal returns, the thermoregulation remains at the second set point. 

The display periodically shows the following: 

2.ter Sollwert 

or 

2nd Setpoint 

or 

2e val. Nomin 

When the control signal is present, the set point can be altered and become re-effective 

again. 


weiter: 

IntExt 

or 

continue: 

IntExt 

Release signal replaces the function of program 3. 

or 

continue: 

IntExt


weiter: 

AIF:Ti Te 

or 



continue: 

AIF: Ti Te 

 

33 

or 

continue: 

AIF: Ti Te 

The release signal sets whether the internal or external temperature is sent to the analogue 

port. 


weiter: 

Standby Mode 

or 

continue: 

Standby 

or 

continue: 

Standby 

As in option , but the difference is that the release signal starts tempering without 

pressing the thermoregulation key Iϑ. 

Pressing enter 

Weiter: 

SP_SWITCH 

or 

continue: 

SP_SWITCH 

or 

continue: 

SP_SWITCH 

If the control voltage is present thermoregulation will control to the second set point. If the 

control signal is not present the „normal“ set point will be adopted. 

After the program is finished the chosen configuration of the external control signal is 

displayed. 

Please note the following concatenation with program 29: an active option of program 29 will 

overwrite the modes of program 28! 

Program 29: Redundancy modes 

Two machines are so connected that the second equipment takes over the thermoregulation 

if the first one stops. This connection has an effect on the POKO modes, the level control and 

the external control signal. 

Of special note are: 

“Redu Master ”: the POKO mode is set on “POKO off” . The external control signal and the 

level control are unaffected. 

“Redu Slave”: the POKO mode is unaffected. The external control signal and the level control 

are no longer available. 

Please note the references in chapter 8.9. 

After the selection of a program, a message concerning the actual redundancy status is 

displayed. With you can see the alternatives, the Redu Master mode is activated with 

key and the Redu Slave mode with key . With key (default) you can switch 

off these modes.



Program 30: Setting date 

After program selection the following is displayed: 

Datum einstellen 

J: xx M: T: 

or 

Set Date 

J: xx M: D: 

34 

or 

Entrer la date 

A: xx M: J: 

By pressing the old value is accepted, or enter a number corresponding to the value 

range. Enter the last two digits for the year. 

Please note the entry YEAR – MONTH – DAY. The 29.February is taken into consideration as 

a leap year. 

Program 31: Setting The Time 

After program selection the following is displayed: 

Zeit einstellen 

Std: xx Min: 

or 

Set Time 

Hour: xx Min: 

or 

Entrer l’heure 

HH: xx MM:: 

With the existing value is accepted or a number should be entered corresponding to 

the desired time. The 24 hour clock is used. 

Program 32: System Time Display 

The Hotkey is the same as activating the program with 

. Date and time are displayed on the LCD display. Necessary correction is possible 

with programs 30/31. 

Program 34: Air Venting Pause 

This program is used to set the pause time of the pump during the venting function (pressing 

key twice). The pre-programmed value of 70 seconds may not be adequate with highly 

viscous fluids or large external systems. The pause in the pumping allows the air bubbles to 

separate from the fluid. Pause duration of up to 2500 seconds can be programmed. 

Program 35: Compressor Automatic Controls 

There are three options: 

The compressor is turned off. Required cooling only via the HT cooler (if available) or 

natural heat loss 

The compressor is constantly turned on, so the chiller is constantly ready for use. 

(Default setting)- The compressor automatic is activated, the chiller is switched on or 

off depending on requirement. This is energy saving. The down side is that there 

might be a time delay when cooling is required suddenly. 

Program 36: Activating Temperature for the HT 

(control panel with software version 3.4 or later) 

Here the temperature can be entered in °C, for the point at which the high temperature 

cooler (HT) is switched to the chiller. This value should be outside the set point value which 

is to be used for thermoregulation, if possible. If this is not done the control could be very 

unstable. Default: 100°C. 

Program 37: RS- Record Type 

Here, the form of the record (which is printed with program 40) is chosen through the type 

specification. At this time only the standard form is available: Type 1.



Program 38: Time interval for RS Record 

The time intervals between the successive data sets can be selected, as they are produced 

with program 40. Entry of seconds: The default value is 1 second. The limit is 90 min. 

Program 39: Separation Signs for RS Record Type 2 

The RS-Protocol-Data (see Program 40) can be transmitted via the serial RS232 interface of a 

Pcand using standard software to store and display the data. 

(for example: reading with a terminal program like the unistat monitor, display with Microsoft 

Excel,…). Certain separators are sometimes requested between the measured values (in 

tables it is the columns, the lines correspond with the data sets). 

Program 39 offers the following selection: 

(ASCII-hex-code) (decimal) 

1. CR (carriage return) 0x0D (default) 13 

2. LF (line feed) 0x0A 10 

3. CR/LF 0x0D 0x0A 13 10 

4. ‘;’ semi-colon 0x3B 59 

5. ‘,’ comma 0x2C 44 

6. space 0x2O 32 

7. TAB (tabulator) 0x09 9 

Program 40: RS report on 

The unit status is being send in defined form to a connected PC via the interface RS232 of 

the control unit (Plug Stv 12) using a Huber data transmission cable (order no 6146). The 

relevant software is required for the PC (for example the unistat monitor), to analyse the 

data. The report is sent in the time interval set with program 38. The protocol will end after 

program 41 is called up. 

All signs of the protocol conform to the ASCII-standard. 

The transmission parameters: 

• 1200 Baud (changeable with program 85) 

• 8 data bits 

• 1stop bit 

• no parity bit 

• no hand shake 

Contents of protocol type 1 (see program 37) 

1. group 3 synchronising bytes (0x3A, 0xFB, 0x57) 

2. group form feed (0x0c) 

3. group Date and time 18 bytes (day month year hour: minute: second: ending line feed 

(0x0A)) 

4. group actual value internal 

5. group actual value external 

6. group set point value 

7. group status flags 

Format of group actual values/ set point value: 

1. character: ‘+’, if the temperature value is >or 0 

‘-‘, if the temperature value is < 0 

2. character: hundred 

3. character: tens 

4. character: single 

5. character: tenth 

35



6. character: hundredth 

7. character: line feed (0x0A) 

Format of the group of status flags: 

Only the signs are getting sent which correspond with the status ‘true’, after that a line feed 

(0x0A). The length of this group is variable, consist at least of the sign ‘I’ or ‘e’ and the 

finishing sign (line feed, 0x0A). 

Meaning of the single status flags (note capitals): 

e external tempering method pre set 

i internal tempering method pre set 

U circulation activated 

I internal tempering on 

E external tempering on 

H status ‘fault’ 

O oil pressure fault 

T external level protection installed 

N low level alarm 

S current consumption failure 

D status ‘pressure without circulation’ 

If a program is activated: 

Tx tempering program with number x is activated 

Syy segment number ‘yy’ is currently run (segment ‘0’ represents the ‘starting phase’) 

If the watch-dog is activated: 

W0 watch-dog has been triggered, tempering was stopped 

(program 45 option pre selected) 

W2 watch-dog has triggered, tempering on to the second Set point value 

(program 45 option pre selected) 

Program 41: RS record off 

The reporting which was started with program 40, constantly repeated until the RS record 

function is switched off. 

Program 45: Watch–dog Function 

The watch-dog function (also known as ‘dead mans head’) is for higher safety, if the 

thermostat is controlled by a computer via the RS232/485 interface. The call up of program 

45 is only accepted if the unistat or Unichiller is controlled by a PC already, therefore it is in 

the ‘remote’ mode already (see Appendix C). Once the watch-dog function is activated, the 

connected PC has got to send the ASCII sign ‘delete’ (0x7F) to the unistat control at least 

every 30 seconds. If this sign is not sent after 30 seconds, the unistat control assumes, that 

the PC is down or the connection has been interrupted, ‘the watch-dog function releases’. 

The following reactions are possible: 

watchdog function switched off (Default) 

watchdog activated. On activation of the watchdog function the thermostat stops 

tempering. The code 55/… is generated. 

watchdog activated. On activation of the watchdog function the thermostat tempers 

up to the second set point value (set with program 4). The message 54/.. is 

generated, which can also be read with program 10. 

36



The release of the watchdog function can be checked with program 40 via a connected PC 

(Flag W0 or W2). 

Program 46: Analogue interface – Control using current signal 

This program is used to set the response to a 4 to 20 mA signal from an automated control 

system. The following options are available: 

(Default) the analogue current will be ignored. 

The analogue current will issue the set point value. 

The analogue current will vary the load in the range 

–100% < = load< = +100%. 

The analogue current will vary the load in the range 

0% < = load < = + 100%. 

The options and allow the Unistat temperature control to be bypassed and the 

current signal sends directly to the final control element. This means that the external control 

system has to have a temperature controller. The advantage of this is that special controller 

algorithms can be used. 

Option allows the complete performance range of the refrigeration and heating systems 

to be controlled. The 4mA signal corresponds to 100% refrigeration power; and the 20mA 

signal corresponds to 100% heating power. In the middle is the value for neither heating nor 

cooling. 

Option allows the analogue current to control only the heating. The refrigeration must 

then be fixed to a particular power level. This can be done using either program or a 

command issued via the digital interface. This mode of operation is advantageous when 

constant temperatures are required, and the system has little or no dynamic temperature 

changes. The described conditions fix the machine operation so that there will be no 

significant variation in load. Typical applications of this program could be tempering of small 

masses, especially when using temperature ramps and calorimetric measurements. 

Program 47: Analogue Interface Monitoring 

As long as the unit is connected to an automation system via the 4…20mA signal, it might 

be required that a safety cut off for the unit is made when the given set point value fails (for 

example due to an interrupted connection). In this case switch program 47 to ON. If a safety 

cut out is not required when program 46 is activated, switch program 47 to OFF (Default). 

The setting remains after mains switch off. If program 46 and program 47 are activated and 

the current falls below the minimum analogue interface entry current this can lead to a safety 

cut off with the message 68/x. 

Program 49: Parameter limits 

The temperature limits are displayed according to Unit type. 

Program 51: Automation For The parameter ‘object mass’ 

(Only in units that use ‘OBJECT MASS’ in program 9) 

To help the search for the most suitable control parameter sets, the following function should 

be used: If program 51 is used after a tempering program, each succeeding run the parameter 

‘OBJECT MASS’ (see Program 9) will be incremented by 1. If a tempering program like the 

following is used: 

1. Ramp (or set point value jump) to temperature 1 

2. Staying with temperature 1 

37



3. Ramp (or set point value jump) to temperature 2 

4. Staying with temperature 2 

With repeated runs, by logging temperature of the object using a recorder, the best parameter 

be found automatically. 

Example: 

• Connect a monitor to log the object mass. 

• Enter the short tempering program shown above using program 20. 

• Choose the function of constantly repeating of a tempering program in program 21. 

• Start the tempering program with program function 23. 

• Run program function 51. A short message ‘automove on’ appears. 

• Set the parameter ‘object mass’ with program 9, with which to start the testing 

(for example 0) 

If the tempering program is repeated the operator can make sure the parameter ‘object mass’ 

is incremented by one on every run, with program 9. The incrementing of the parameter 

‘object mass’ goes up to 14 then starts again at 0. 

Special case: The value ‘object mass’ = set at 15. The control parameter ‘P’ and ’I’ will get 

changed with every program repeat, not the object mass (see program 9). Object mass = 

assumed at 15,you will be asked on call up of programme51 

for the highest counting control parameter ‘P’ or 

for the highest counting control parameter ‘I’ to choose. 

! As long as program 51 is activated, the tempering method cannot be changed (not 

with program 3 nor with a release signal). 

Program 52: Standard Parameter Set - Default 

The following are a list of the default settings: 

Program 0: Set Point 20°C, 

Program 1: Minimum set point 5°C, 

Program 2: Maximum set point 35°C, 

Program 3: Control Mode intern 

Program 4: 2 nd Set Point 5°C. 

Program 5: Mains failure Automatic OFF 

Program 6: minimum set point monitoring via the POKO fixed at 1K 

Program 7: maximum set point monitoring via the POKO fixed at 1K 

Program 8: POKO OFF 

Program 9: internal Object Mass 5 

external Object Mass 15 

with P=4 und I=8 

Program 12: Pt100 Offset internal 0 

Program 13: Pt100 Offset external 0 

Program 14: Set Point Tracking OFF 

Program 16: Pt external display OFF 

Program 18: Delta-T Limiter 100K 

Program 20: Thermoregulation Program No change 

Program 21: Thermoregulation Parameter No change 

Program 25: Start date wird gelöscht 

Program 26: Thermoregulation Program Tracking No change 

Program 27: Time Base Minute 

Program 28: external control signal inactive 

38



Program 30+31: Date and Time No change 

Program 34: Venting Pause 70 seconds 

Program 35: Compressor Automatic Auto 

Program 36: HT start Temperature 100°C 

Program 37: List type Type 1 

Program 38: Protocol Timer 5 sec 

Program 39: List Separator Type 1 

Program 40: Protocol off 

Program 46: AIF off 

Program 55: Degassing off 

Program 68+69: Tempmove off 

Program 73: Advanced Control off 

Program 75: Fixed Cooling Power 30% 

Program 84: Slave address 1 

Program 85: Baud rate 1200 Bd 

Program 86: digital Interface RS232 

Program 90: Language deutsch 

Program 106: maximum Temperature Limit (external) 320°C 

Program 107: minimum Temperature Limit (external) -150°C 

Program 108: maximum Temperature Limit (internal) 320°C 

Program 109: minimum Temperature Limit (internal) -150°C 

Program 118: Delta-T Monitoring 140K action: warning 

Program 135: Analogue Interface Calibration No change 

Program 136: Analogue Interface Calibration No change 

Program 137: Analogue Interface Temperature -40°C to +100°C 

Program 138: AIF Definition Of Exit Signal Internal PT 100 

Program 140: AIF Filter No filter therefore quick 

Program 141: Analogue variable 0% 

Program 180: Heating Power Limiter 100% 

Program 181: Cooling Power Limiter 100% 

39

Program 55: Degassing 



! This is one of the most important functions for the use of the unit when thermofluids 

are being changed. It happens often that customers with new units are confronted with an 

apparent error code, which is caused when the customer not does not degas the first filling 

(the real first filling happens in the factory in the trial runs). 

If there is still a residual liquid with a low boiling point in the liquid circuit, vapour bubbles will 

develop when heating. (For example: a high temperature tempering is to be carried out using 

silicon oil and the equipment was previously filled with ethanol, for low temperatures.) The 

minimum pressure might not be able to be sustained at the pump exit due to bubbles in the 

circuit. This causes the ‘flow switch’ to signal that there is no circulation. Unistat control 

reacts immediately by switching off heating (yellow LED in Flow picture goes off- LED 7 in 

fold out chart). If the minimum pressure doesn’t build up again within a few seconds at the 

pump exit, the tempering and the circulation will be stopped. The message 41/…will be 

indicated and the tempering must be restarted. 

Attention: when degassing with high temperatures the expansion tank can become hot! Do 

not touch! The vapour causes the formation of bubbles, these escape through the sight glass 

and expansion tank, a slight fluid exchange takes place within the expansion tank. Different 

to the normal operation, the fluid temperature in the expansion tank adopts the temperature 

of the thermoregulation circuit. 

Using program 5 the ‘flow switch’ can be forced to increase the tolerance time to 5 minutes. 

During this time the liquid will have cooled down enough to stop it from developing steam 

bubbles and the pump pressure will be built up again. The heating will get switched on again 

(limited to 50%) and the process will continue. Every time the circulation fails during the 

degassing, the message in the LCD window will show ‘no circulation pressure’. An acoustic 

signal will sound in the last seconds before the tolerance time is running out. Then the 

operator can press the key ‘tempering’ to refresh the tolerance time. After that the 

pressure fall will be tolerated for 5 minutes. 

! Please remember you do not have any insurance for any damage, which may occur 

through leaks in the hot liquid circuit, when using program 55. That is why this kind of 

equipment should only used under supervision. If a leak occurs the unit must be switched off 

straight away. 

This function is lost when the mains are switched off. Please note the information in 

paragraph ‘external level’. This safety feature will always respond when the level is reducing. 

Please note information in paragraph ‘venting and emptying’ for the setting of the venting 

valves. If the unistat being used is equipped with an HT cooler, the branch of the heat carrier 

circuit, which goes through the evaporator of the chiller, can be isolated for some time. To 

degas the thermofluid the mixture can, by lowering the set point value, connected with the 

call for cooling, for example the temperature of 30°C (manually via program 0 or via a 

tempering program). At the end of the degassing small amounts of nuisance liquid might have 

collected in the expansion vessel. The expansion vessel can be emptied without draining the 

circuit. (This statement is only relevant for the tempering of externally closed vessels). 

! The expansion vessel should be emptied to remove the condensate. 

This program can only be used when pressure switch F14 has sensed the correct information 

about pressure increase and pressure drop in relation to circulation. 

See also comments, program 116. 

40



Program 56: ’Descaling’ 

This moves the water solenoid valve of condenser and stepper motor of the main cooling 

water periodically (only for UNISTATS T32XwHT). This is necessary to circulate warm 

descaling medium through the heat exchanger of the cooling water circuit, when the machine 

is off and the cooling water pipes disconnected. The thermofluid circuit does not have to 

emptied for this, nor does it have to be disconnected. The amount of descaling you have to 

do depends on the softness of the water (like in a coffee machine). If the water is very hard 

and the unit is used a lot, it might need to get descaled once every month, or in extreme 

cases even once every fortnight. 

! If the descaling intervals are too long the heat exchanger might become blocked with 

chalk and might only be able to get fixed in an expensive repair in the factory, which is 

not part of the guarantee. 

Program 57: ‘Max cool power’ 

This is only for UNISTATS T32XwHT 

When the temperature is below 75°C the cooling water valve is opened further. 

Program 59: Compressor Clearance 

In the large UNISTATS a compressor oil sump heater is built in. After the switching on at the 

main switch, on the reverse side of the unit, this heater takes ca 2 hours to get the 

compressor oil up to using temperature. If an attempt is made to start the tempering earlier, 

the message ‘No Compressor Clearance’, now only the pump and the heating are functioning. 

ONLY IN EXCEPTIONAL CASES AND ONLY, IF THE ROOM TEMPERATURE IS FOR CERTAIN 

ABOVE 20°C, this monitoring can be by-passed only once by activating program 59. 

! Regular use of this option with low surrounding temperatures can cause the 

destruction of the compressor! 

Program 68: Tempmove – flow temperature sensor 

This program allows the selection of the flow temperature sensor. This selection selects only 

the temperature control. Options to are available: 

(Default) the controller evaluates the temperature based on the measured 

value from the unit flow sensor (Tint). 

Pt external socket The controller evaluates the temperature based on the measured 

value from an external Pt100 sensor connected to the PT extern socket (Lemo 

connector). 

Analogue interface The controller evaluates the temperature based on the input 

current at the analogue interface. To do this program 137 must be used to set the 

temperature range of the analogue interface inlet current. 

Digital interface The controller evaluates the temperature, which is issued from a 

PC or PLC, which is issued to the control panel. 

Note: For relevant safety checks the temperature actually present at the units internal flow 

temperature sensor is used. This setting is not affected by switching main power off. 

41



Program 69: Tempmove – reactor temperature sensor 

This program allows the selection of the reactor temperature sensor. This selection selects 

only the temperature control, especially the cascade controller. Options to are 

available: 

(Default) and The controller evaluates the temperature based on the measured 

value from an external Pt100 sensor connected to the PT extern socket (Lemo 

connector). 

Analogue interface The controller evaluates the temperature based on the input 

current at the analogue interface. To do this program 137 must be used to set the 

temperature range of the analogue interface inlet current. 

Digital interface The controller evaluates the temperature, which is issued from a 

PC or PLC, which is issued to the control panel. 

Note: This setting is not affected by switching mains-power off. 

Program 73: Advanced Control 

Note: This program is only to be used for certain applications. 

Program 73 can be used to select the temperature controller to be used. The internal or an 

externally located temperature controller, part of an automation program can be selected. 

Option selects the normal thermoregulation method with the UNISTAT Control 

(Default). 

Options to option are not available. 

Option fixed heating power and fixed cooling power. This option is only to be used in 

combination with an automation system. 

Option Fixed cooling power, heating power controlled. 

Option can only really be used when at least one of the powers are controlled via the 

temperature controlling element of an automation system. Normally the cooling power will be 

fixed and the temperature control will be achieved by varying the heating power. 

Option This option uses the temperature controller of the UNISTAT Control. The 

difference here to the standard option is that the cooling power is pre set. The temperature 

controller uses only the heating to regulate to the set point. 

Program 75: Fixed Cooling Power 

In connection with Program and possibly also Program a fixed value for the 

cooling power can be set. Note: If this value is not achievable for technical reasons, then the 

maximum available cooling power is used. 

This setting is not lost after mains off. 

Program 84: RS485 – Slave Address 

To start a connection via the RS485-bus every connected unit has to be given a slave 

address. The selection of the address is initiated with the summons 

. The following is displayed: 

Slaveadr: x 

new(1 ... 30): 

The current address is displayed and the possible address range. If the program is exited 

using , the program returns to the old setting. An address between 1 to 30 must be 

chosen. 

The slave address is not lost after mains off. 

42



Program 85: Baud Rate for serial data transmission (RS232/485) 

The transmission speed with which your unit is communicating with the connected PC, can 

be chosen in one of four rates. Enter , the current baud rate appears: 

Host Bd-Rate 

Akt1.2kBd 

With you leave the program without change, with you go on in the selection: 

9.6 4.8 

2.4 1.2 

Once the selection is completed the transmission speed starts straight away. Always 

remember that the connected units (in a RS485-bus system) are set at the same transmission 

speed and the master (so the PC, which has a control software installed) has to be set at the 

same speed. 

Behaviour after MAINS OFF: 

This setting is not lost after mains off. 

Program 86: Selection RS232 ↔ RS485 

Two digital serial interface standards are possible with the control unit software, both are 

done via the same plug connector (Plug Stv 12). It is possible to work with only one at any 

one time. That is why program 86 offers the selection possibilities. This setting remains after 

mains off. 

Program 90: Language Selection 

Program 90 offers the choice between German, English and French. A short reminder of this 

program is displayed after mains switch on. 

Program 93: Production number/serial number 

(control panels from software version 3) 

This is the serial number of the control panel. 

Program 94: Control Panel Identification 

(control panels from software version 3) 

A marking, which indicates which printed circuit board is in the control panel. 

Program 98: Version number 

(Control panels from software version 2.4) 

The version number of the software for the control panel appears in the first line. The 

information about the controller software version is in the second line. 

Program 106: Maximum Temperature Limit (for external Pt sensor control) 

If the value set using this program is exceeded for more than 3 seconds an alarm is triggered. 

A device message 73/x will be recorded (see Program 10). Note: The default setting for this 

value is 320°C, a value that the external Pt100 sensor will never experience, whether it is 

connected or not. 

43



Program 107: Minimum Temperature Limit (for external Pt sensor control) 



value is -155°C, a value that the external Pt100 sensor will never experience, whether it is 

connected or not. 

Program 108: Maximum Temperature Limit (for internal Pt sensor control) 

This monitoring is first activated, when tempering, the flow temperature has been below the 

set maximum temperature limit. This means that the temperature in the thermostat must 

have been below this set point before the alarm can be triggered. The temperature must be 

3K below the set point before the monitoring is activated. This method allows simple use of 

this monitoring feature even when the alarm values are below the room temperature. The 

refrigeration machine must set the temperature before the alarm can be triggered. 


A device message 78/x will be recorded (see Program 10). 

Note: The default setting for this value is 320°C, a value that the external Pt100 sensor will 

never experience, whether it is connected or not. 

Program 109: Minimum Temperature Limit (for internal Pt sensor control) 



value is 

-155°C. This value should never be experienced by the internal Pt100 sensor. 

Program 111: venting program 

Venting can be activated or deactivated by pressing circulation button twice or alternatively 

through this program. 

Program 116: Flow 

It is important for thermoregulation to have a stable circulation pressure, which is evaluated 

by switch F14. (see 1.wiring diagram). Program 116 allows the status of the F14 to be 

checked on LCD-display. In line 1 on the right part of the display the actual status will be 

shown. 

F14: ON 

Means, that the switch shows the pump pressure, but the pump is at standstill. There is 

static pressure on the system. There is no safety for hose bursting during thermoregulation. 

F14: OFF 

Means, no pump pressure is measured. 

44



Program 118: Delta-T Band Monitoring 

This monitor should be used when, at external tempering mode (see 6.1.2), glass equipment 

or a product has to be protected from too high a temperature difference. 

After program request you are queried, which action is to be executed by the monitor. You 

can confirm or modify the action. 

Possible selection: give a warning or an alarm (and stop). 

Afterwards the actual monitoring temperature difference is displayed. You can give values 

from 10K to 140K. Outside the temperature range an error with code 118/1 is released, 

when T-external –T-internal < Delta-T Band is valid. 

Please note: the monitor alarm is released independently from the cause (source). 

It may be that a sudden temperature rise by exothermic or a temperature drop caused by 

dosing leads to the release. 

The monitor function is not attached to the delta-T Limiter, it works independently of it. 

Program 135: Analogue interface – calibrating of the AIF entry current 

The AIF entry current is calibrated with this program. The current limit for the set point value 

setting via the AIF. This process is not simple. An assignment follows, of the current for the 

variable ‘zero line’ and ‘full output’. The value of the two variables at the time of the 

calibration is not important. 

After calling up the program: 

Input 

Wenn Strom für 

Nullin. OK: 

or 

If lowcurrent 

OK: 

45 

or 

si curant bas 

 

Now set the required value, normally 4mA. Wait 5 seconds and then press , 

(the calibrating will be processed with a time constant of 1 sec.) 

The following appears: 

Strom für End- 

ausschl.OK: 

or 

if finalcurr. 

OK: 

or 

si curant final 

 

wait about 5 seconds after setting the current for the zero line, then press . 

Please note the following: 

The accuracy of the transfer of the current signal into a temperature, will depend on the 

temperature range. This range should not be unreasonably large. 

If a signal filtering is necessary, the set point value can be smoothed using a filter 

(see program 140). 

The current range which can be analysed, starts with ca. 1mA and ends with ca 26mA. This 

range should be used to get the most accurate measurement! 

If it is attempted to set a value of current for the final current less than the setting of the zero 

line, the following will appear: 

Nicht zulässig 

or 

Fct not Accepted 

or 

Non autorisé



The warning message 181 „AIF parameter initialized” is displayed when wrong calibration is 

sensed after switching on. 

Program 136: Analogue Interface – calibrating of the AIF Exit Current Range 

The exit current range of the AIF is calibrated with this program. After calling up this 

program, the following appears: 

Kalib. AIF 

4...20mA OUTPUT 

As a note for the program function. Internally the range is 0,1..26mA is assigned to the range 

of all numbers 0..1023. Therefore a whole number appears on the display when calibrating 

minimum and maximum. 

After the following is displayed: 

Kalib. LOW 

akt: 150/ 

Now the current is flowing which corresponds exactly to the zero line. With number is 

reduced, with ‘slowly’ increased. The setting can be made directly as a number 

and finish by pressing . If the number is reduced, the current gets smaller, and vice 

versa. Once the measuring value is correct for the unit connected with the unistat or 

Unichiller via the analogue interface, close the LOW calibration with and calibrate of 

the “maximum deflection”: 

Kalib. HIGH 

akt: 991/ 

Please set the required current for the ‘maximum deflection’ when using the above explained. 

Permitted values for the calibration are 0..200 for the minimum and 800..1023 for the 

maximum. You can expect roughly 0.6mA when selecting 25mA for a setting of 1023. If 

these limits are not enough, we recommend you seek further possibilities for calibration 

external to the unistat control, as you would exceed the 4..20mA-standard. If you exceed the 

permitted range, this will result in a message 19/x and resetting to the default settings after 

next rebooting of the Control Panel. 

Program 137: Analogue Interface – Current/Temperature Relationship 

Setting of the temperature for the signal zero line (minimum exit current) and the maximum 

current output. 

This program is used to assign the analogue current (programmed in 135/136) to a calibrated 

temperature range. 

After program selection the temperature for the signal zero line is entered. If the operator 

quits , without entering a number, the previous setting remains. In the second step 

the temperature for the end temperature is entered. Please note that the difference of entries 

may not exceed 300K. 

Program 138: Analogue interface – Assigning the exit signal 

The exit signal for the analogue interface is made of the difference of two values, V1 and V2. 

The differentiating procedure makes it possible (for example the difference between set point 

and actual value, or between internal and external actual values) to be signaled externally via 

the AIF. 

46



Signal = V1 – V2 

This program is used to determine which temperatures are used for V1 and V2. After the 

program selection a note is displayed about the form of the signal. After using the 

following list appears. 

V1: 0: NULL 

1:SW 2: Int 3: Ext 

For Example: 

To give out the internal actual value 

V1 = =internal actual value 

V2 = =0°C 

V1 – V2 =internal actual value – 0°C =internal actual value 

(0) zero: Temperature 0°C 

(1) SW: set point value 

(2) Int: internal actual value 

(3) Ext: external actual value 

(4) Var: ‘analogue variable’ – 0..100%, to be set with program 141 

Program 139: Analogue interface – Assignment Display 

This is set with program 138, the current definition of the analogue exit signal is displayed. 

Program 140: Analogue interface – Filter Constant 

For the analogue entry signal a smoothing filter is used. 0,1,2,4 and 8 seconds can be 

selected as a time constant. 

Program 141: ‘Analogue Variable’ 

Here the value 0..100% can be set. The default value is 0%. The main use for this program 

is the control of another laboratory unit (for example stirrer, which is fitted with an analogue 

input), with the analogue exit, the UNISTAT CONTROL. The PC software ‘UNISTAT 

PROGRAMMER +’ uses this function and makes it possible to control an external laboratory 

unit and the UNISTAT simultaneously from a PC. 

Program 142: AIF-parameter-reset 

When program is being selected and activated with button all AIF-parameters will be 

reset to the factory default. 

Program 137: zero line -40°C 

maximum deflection+100°C 

Program 138: internal actual value 

calibrating value: 

for entering current: 167 und 816 

for exiting current: 160 und 880. 

Program 143: „XL_CHARGE“ (UNISTAT XL only) 

Charge XL vessel. 

Program 144: „XL-Power“ (UNISTAT XL only) 

Defining the % bypass, to decide the rate of addition. 

47



Program 145: „XL – Vorhalt“ (UNISTAT XL only) 

Advises the controller over the forthcoming XL Event. The controller integral factor (the I 

factor of the PID controller) is distorted. This prevents the controller working against a very 

rapid cooling action. 

Program 146: „XL – Starttemperaturdifferenz“ (UNISTAT XL only) 

Starts an XL Event on reaching a preset temperature difference between the actual value and 

the set point. 

Program 147: „XL – Mode“ (UNISTAT XL only) 

Activates the XL Mode, if not activated the unit will behave as a normal Unistat (not HT) 

Program 148: „XL – Timer“ (UNISTAT XL only) 

Interrupt Mode 1; Defines the timeout for the XL-Event 

Program 149: „XL – Stoptemperaturdifferenz“ (UNISTAT XL only) 

Interrupt Mode 2; Defines the temperature, when reached the XL-Event will be ended. The XL 

vessel is then isolated from the circuit by the slider valve. 

Program 180: Heating Power Limiter 

The heating power can be limited to n% 0

Appendix B -- Unit Messages 


Appendix B - Unit Messages 

The unistat control has a memory for messages. There results of the internal status 

monitoring are stored. Only the messages which have the status of a warning or a fault are 

displayed without requesting them. 

Please note that the date and time is always given. That is why it is advisable to correct the 

time occasionally, e.g. summer time or winter time. The most recent messages (up to 25) can 

be read with program 10. 

Example: 

13.02.97 11:48 

Meldg.: 1/0 

The top line indicates that the message was generated at 13th February 1997 at 11.48. 

The second line has the actual message in form of a code/index, so in this case code 1 with 

index 0. 

The Index is always given, but is only of meaning with some codes. The indices are explained 

later. 

1/: 

Switching on unistat control. 

1/0: Mains on 1/85: pump started 1/73: tempering started 1/65: turn on mains 

failure automatic 1/69: initialising error when turned on 

2/: 

2/79: turn off via the red - key 

2/1..2/9: turning off thermoregulation program No. 1...No. 9 

2/111: Switch off command from PC (see Appendix E and F) 

2/115: Switch off command from «External Control Signal» - Program 28 «Stand By» 

Note: The switch off command for „ending a Thermoregulation Program“ has higher priority 

than „Switch Off Command from PC“. 

4/: 

Programming of the external control signal (release signal, program 28) was changed. 

The index shows which assignment was programmed before the changed. 

4/0 release signal without meaning 

4/1 release signal for stop/start 

4/2 release signal second set point value 

4/3 release signal for change of tempering method 

4/4 release signal for changing the analogue out signal 

4/5 release signal as start /stop signal 

5/: 

The programming for the potential free contact (POKO, see program 8) was changed. 

The index shows which assignment was previously programmed, before this change. 

5/0 no function 

5/1 Temperature range monitor (see program 6,7) 

5/2 POKO as alarm 

5/4 control of the pressurising pump ‘UNIPUMP’ 

5/8 TP track [1] in tempering program 

5/16 TP track [2] in tempering program 

49

14/: 

Status error in digital interface 



15/n: 

Current input from unistat control was measured, the value does not correspond to the 

programmed value. 

15/1 controller electrical power too low 

15/2 pump electrical power too low 

15/4 compressor electrical power too low 

15/6 pump – and compressor electrical power too low 

15/16 controller electrical power too high 

15/32 pump electrical power too high 

15/64 compressor electrical power too high 

15/96 pump – and compressor electrical power too high 

17/: 

Error in parameter memory for setting of analogue signal. 

Check the setting (see programs 137, 138, 139). 

18/: 

Entry error at analogue interface 

19/: 

Error at analogue interface (exit) 

21/: 

A defect in data memory for unit functions. 

This is why the following standard unit functions are stored as defaults: 

Internal tempering method pre set (see program 3) 

Mains failure automatic off (see program 5) 

Time base minute (see program 27) 

‘external control signal’ not activated (see program 28) 

POKO off (see program 8) 

22/: 

A defect in data memory for parameter settings 

That is why the following standard parameters are stored as defaults: 

Set point value: 20°C 

Tempering off 

5°C minimum set point value 

25°C maximum set point value 

26/: 

RAM error: defect in controller data memory of the electronic controller. 

Please contact the manufacturer. 

28/: 

Parameter error. New installation for POKO settings and the ‘second set point value’ have 

been set. (see programs 4,6,7,8) 

29/: 

Baud rate wrongly initialised. 

50



30/: 

Error in the serial interface recognised (TXD error) 

31/: 

Data exchange between control unit and controller interrupted. 

33/: 

The length of the thermoregulation program is not correct. The length was set to 0 

(See program 20) 

34/: 

A defect in data memory range for the thermoregulation program has occurred. The program 

length was set to 0 and the starting temperature was given with 20°C. The settings of the 

segments were not corrected, they can be used again after activating by setting the ‘stop 

mark’ (see program 20). The contents of the segments should be checked. 

35/n: 

An attempt was made to start thermoregulation program No. n, which has a starting 

temperature which is outside the range for the minimum or maximum set point value. 

36/n: 

The tempering program No. n was started. At least one of the end temperatures is outside 

the limits given for the minimum or maximum set point value. 

37/n: 

Tempering program TP No. n was started (see program 23) 

38/n: 

Tempering program TP No. n was stopped (see program 22) 

39/n: 

A program has one segment with duration identified as being outside the permitted range. 

(Correct with Program 20) 

40/: 

Static pressure in thermofluid circuit. The pressure sensor has signaled although the 

circulation pump is not running. 

41/: 

No pressure in thermofluid circuit. The flow sensor shows a drop in pressure. Cause: 

Pump not working (circuit breaker?), insufficient ventilation of pump motor (paragraph 8.1), 

or the formation of gas bubbles due to degassing (happens when heating, see program 55). 

Maybe the pump overload has tripped. This can also occur when a fluid with a density in 

excess of1kg/dm³ is used. Wait a short time and try to restart. Please make sure the fluid in 

the working area has a viscosity no higher than 50cSt! 

UNISTAT 14X, 16X, 290w and T237: Is the rotation of the pump correct? In new 

installations it must be insured that the phase rotation in a three phase installation is correct, 

i.e. No reversed phases. If no pumping noise is there, the phase monitor relay has prevented 

the start. 

51



42/n: 

Error of external level sensor 

42/0 level switch has been activated. Alternative: External Unipump is not working. 

42/1 defect in the electrical connection to the level sensor (‘level test’) 

43/: 

Collection error 

A few sensors have been grouped together. The cause of the fault is model dependent. 

If this happens repeatedly, please contact our service department. 

44/: 

Unit type error. The recognised unit type is not correct, therefore typical settings for the unit 

type can not be processed. Thermoregulation is not possible. 

Please contact the manufacturer. 

45/: 

Warning ‘condensing temperature monitoring’. The unit power has to be restricted, so that it 

does not exceed the maximum condensing temperature. This warning displays insufficient 

cooling of the condenser. The heat exchange fins could be blocked in air-cooled models, the 

cooling water supply might be restricted in water cooled models. The cooling water 

temperature should be checked (see condensing temperature control). 

46/n: 

Sensor defect. The sensor measurement specified by the index is outside the permitted limit. 

If the index 2 is displayed, the cause might be in the externally connected Pt100 sensor, if 

the tempering method was turned to external (see program 3). If an external Pt100 sensor is 

connected, please disconnect it and restart the unit. Problems with the screening or isolation 

of the external sensor could confuse the internal measuring system. 

46/1 internal sensor (Pt100) 

46/2 external sensor (Pt100) 

46/4 condensing temperature sensor (Pt100) or condensing pressure sensor 

(0…30 bar) 

46/8 Evaporator end sensor (Pt100) 

46/16 Pressure sensor for vapour pressure in refrigerant circuit 

If more than one error appears, the controller will sum the indices, for example: 

46/6 external Pt100 and condensation sensor 

47/: 

Warning: Watch dog 300ms were exceeded. 

49/79: 

The pump has been turned on but not the thermoregulation. The flow temperature has exceeded 

the value of the maximum set point value. The circulation pump was turned off. In a well 

insulated system the temperature can reach 75°C, simply through the heat of the pump 

(mechanical energy conversion). The pump must be turned off to allow the unit to cool down. 

51/n: 

The unit message with code 51 will be displayed, every time there was a fault in the unit, 

which is sent from the controller to control panel. The unit has switched off for safety 

reasons. 

52



The index “n” gives the information about which components were the cause for the fault. 

Usually you should contact the service engineer, as often knowledge of refrigeration is 

required to understand what kind of error is present. Often there is a connection with 

previous messages and with the time sequence the messages are being displayed. Please 

always note the amount of messages there were related to the actual incident (with program 

10 and by pressing the operator scroll to the next oldest message and with to 

the next newest message) and tell the manufacturer these. 

This can expedite any repair, which may be required. 

Note: some faults can be caused by operator failure, the most common being 51/7, valve in 

cooling water system closed. 

51/2 Condensing Temperature Sensor 

turned off – the condensing temperature has reached the upper limit and not receded 

during monitored time. The error message is related to the cooling stage, which is 

controlled by a stepper motor valve. A hanging stepper motor inadequate cooling 

water pressure could be the cause. 

∗ With air cooling: - one stage machine (Tango): 

Air intake not OK (too warm, material sucked in, dirty) 

- multiple stage machine: 

high pressure machine is not delivering enough power? 

∗ With water cooling: - cooling water pressure? Cooling water filter dirty? 

(Note: the pressure in the return line of a cooling water system may be too high. 

Pressure difference between the flow and the return must be observed. 

51/3 The low pressure MOP sensor 

The stage, controlled by stepper motor valve has turned off – the low pressure –MOP 

has reached the upper limit value and did not recede during the monitored time. (MOP 

is the highest permissible operating pressure for a compressor) 

51/4 The superheat controller necessary for the minimum superheating has turned 

off, because the actual value could not exceed the pre set minimum value during the 

monitored time. (fault in cooling machine or viscosity of the heat carrying liquid too 

high or not enough circulation, may be stepper motor stuck). 

51/5 Monitoring of the Relay for the complete isolation of the heater, chiller and 

circulation has discovered a defect. This message can only arise as a result of the 

switch on self-diagnosis tests which are run during the start up. 

51/6 The minimum flow rate of refrigerant 

was achieved. Stepper motor can not open valves. Stepper motor stuck? No 

circulation, evaporator „iced up„ due to water in fluid? Isolation valve in the 

thermofluid circuit? 

Defrost, try again. Renew liquid or de-gas. 

51/7 The over pressure trip switch of high pressure stage 

has tripped. In air cooled units: Air flow insufficient, maybe the condenser fins on the 

back of unit behind safety grille require cleaning. 

In water cooled units: Cooling water flow interrupted? 

Enough water pressure? Cooling water filter blocked? 

Additionally in unistat 380, 385, 390, 420, 14x and 16x: 

press red or black button on side of unit! 

53



51/8 The over pressure trip switch of middle pressure stage 

has tripped. (Only in multiple stage coolers) 

51/9 The over pressure trip switch of low pressure stage has tripped. 

(only in multiple stage coolers) 

*51/10 Over current relay 1 of the high temperature stage or pump (unit dependant) 

has tripped. 

*51/11 Over current relay 2 of the medium temperature stage or low temperature 

stage (unit dependant) has tripped. 

If this code shows up on a time where the contactor in question is supposed to be 

OFF (e.g. after the red stop-button was pressed), then the message can also 

mean that the other contactor on the same component is stuck or its actuator doesn't 

turn off. Example: The two windings of the Bitzer compressor in Unistat 16X. 

*51/12 Over current relay 3 of the low temperature stage (only UNISTAT 420) has 

tripped. 

51/13 Thermal overload in low pressure compressor has operated 

51/14 PLC delivers code that is not permitted 

51/15 Stepper motor valve does not close correctly or compressor power is not 

providing enough cooling power. 

51/16 Thermal overload in high pressure compressor has operated 

51/17 High pressure compressor switched on without permission 

(or medium pressure stage in UNISTAT 420) or K2 is switched on wrongly. 

In units with winding start: Relay for winding start wrongly started. 

*51/18 Contactor HT stage dropped out; or K2 can not be switched on. 

51/19 PLC code unknown 

The code which has been read does not exist. 

51/20 Over temperature monitor 

has signalled. See instruction for the corresponding unistat model, paragraph: over 

temperature monitor. Please note that the display for the over temperature monitor will 

be flashing. 

51/21 Minimum suction pressure not achieved 

When cooling machine is switched on the first time after mains off in the given 

minimum suction pressure was not reached for the stepper motor valve stage. This 

pressure is required as a reference for the control. The cause for this could be a 

sudden mains off during the last tempering. Please note paragraph ‘tempering switch 

off’. Maybe it is enough to switch it off and on again. 

51/22 Kriwan 

(overload switch of compressor) has responded. Please contact service engineer. 

54



51/23 Oil pressure switch 

has tripped. If this error appears after transportation, the contact was probably 

bumped at a sensitive point. In this case it is enough to open the casing, in the bottom 

part you will find the DANFOSS oil pressure switch, press the black button and release 

again. If this does not help please contact the service engineer. 

51/24 By-pass valve error 

in the middle pressure stage. (only in three stage units) 

51/25 By-pass valve time out 

in the middle pressure stage. Switch on time is too long, condensing temperature 

could not be kept low. 

51/26 Internal data transmission interrupted 

Disruption in data transmission controller - control unit 

51/29 Minimum current test – minimum current too high 

After mains on fault. The flowing current is measured, to check that only the 

electronics and the mains isolation relay are using current. If the current is too high, 

possibly the solid state relay is ‘burnt out’, that means it has switched a load without 

permission. A safety cut out is the result. 

51/30 Main heating test 

After mains on error. No current (heater fuse to be checked) 

51/31 Fine heating test 

After mains on error. No current (2A fuse in back of controller housing to be checked.) 

51/32 High temperature stage defect (Unistat 380/ 385) 

(Condensing temperature could not be pulled low enough.) 

51/34 Stepper motor valve setting 

after mains on not achieved–time over running. Is it possible that the unit was turned 

off at the socket from full run? In this case try resetting again for a few times, the 

internal emergency mechanism will solve the problem. If the unit was switched off 

correctly, it could be either the stepper motor could not close the valve or the low 

temperature compressor does not have enough power. 

51/35 Mains isolation relay 

No current is going through the heater or the fine heater, that is why it is assumed 

that the current supply is interrupted (mains relay, or fuses for phase 2 and 3 in 3 

phase current.) This message appears as well when the overheat protection has 

responded. The LED display is blinking red next to the mains switch. 

51/36 Auxiliary contact on Relay K2 is stuck or K2 is supplied with the wrong 

electrical power 



51/38 Control signal for Relay K4 or auxiliary contact is defect 

55





51/40 Relay K3 does not switch on 


51/42 Relay K2 or K3 incorrectly switched on 



51/46 Error in PLC program; part wind start not ok 

51/47 In unistat 16X: Error in valve setting (only when turning on) 

cause: Was turned on to low temperatures too soon. Solution: let pump run on its own 

and then re start. 

51/48 Relay of high pressure compressor is chattering 

51/49 Relay of low pressure compressor is chattering 

51/50 Relay of low pressure stage has not switched on or has tripped. 

Possible solution: Over current relay has tripped 

51/51 Relay of low pressure stage will not switch off 

51/52 Auxiliary contact of Relay K3 sends wrong signal. 

51/53 Necessary condensation temperature for low pressure stage not achieved. 

51/54 Relay K2 and K4 falsely seated or stuck; 

51/55 Relay K4 pulled in, but not K2 

51/56 A Relay is chattering. The Relay is identified via the LED on the PLC: 

Out 13 Out 14 Out 15 

K2: OFF OFF ON 

K3: OFF ON OFF 

K4: OFF ON ON 

Note: The resetting of these errors can only be resolved by switching of at the mains. 

51/57 Power of High pressure stage not adequate 

51/58 Contactor K4 has dropped out. 

51/59 Contactor K4 is stuck 

51/60 Contactor K4 is chattering 

56



51/61 Contactors K2 and K4 have failed 

51/62 Contactor K3 is vibrating 

51/63 Contactors K2 and K3 are stuck 

51/64 Contactor K3 is stuck 

51/65 Contactor K2 dropped out. 

For unistat 160w-161w: compressor contactor has not switched or has dropped out. 

51/66 Low pressure switch of high pressure stage has responded 

51/67 Contactor K3 has failed 

51/68 Pump pressure not present 

51/70 Pump Contactor off/ dropped out 

51/71 Pump Contactor on/stuck 

51/72 Fans failed 

51/73 The high pressure sensor of high pressure stage has responded 

51/74 Relay K4 and K5 are not operating in a synchronised manner 

51/75 Unit type recognition error. 

51/76 Phase sequence relay – fault: Pump does not start because of safety reasons 

due to a reversed phase in the three phase current supply. The electrician must swap 

two phases in the mains cable to achieve correct three phase supply. 

51/77 Gas pressure switch has been tripped (only large UNICHILLER) 

51/78 Thermostat in fan has been tripped (large chiller) 

51/79 Only UNISTAT 290 PLC Status ‚Pressure equalisation‘ not accepted 

51/80 Only UNISTAT 290 PLC Status ‚HT- und NT-Stage‘ not accepted 

51/81 Only UNISTAT 290 PLC Status ‚K6 not switching on‘ 

(K6 = Pump contactor) 

51/82 Only UNISTAT 290 PLC Status ‚K6 stuck‘ (K6 = Pump contactor) 

51/83 Only UNISTAT 290 PLC Status‚ K2 or K3 stuck ‘ 

(K2 / K3 = HT-compressor) 

51/84 Only UNISTAT 290 PLC Status ‚K2 or K3 not switching‘ 

51/85 Only UNISTAT 290 PLC Status ‚K4 or K5 stuck‘ 

(K4 / K5 = NT-Compressor) 

57



51/86 Only UNISTAT 290 PLC Status ‚Kriwan in NT-Stage‘ tripped 

51/87 Only UNISTAT 290 PLC Status ‚Öl-Pressure switch 

NT-Compressor tripped‘ 

51/88 Only UNISTAT 290 PLC Status ‚K4 oder K5 not switching‘ 

51/89 Only UNISTAT 290 HT-Superheat not OK 

51/90 Internal use only 

51/91 Internal use only 

51/92 Thermal contact in pump motor has responded. Thermal overloading. Is the 

fluid too dense or viscous? Is one of the three phases missing in the mains voltage? 

51/94 Maximum gas discharge temperature exceeded. Possible causes, capillary 

pipe switching on 290w, or refrigerant injection or power supply too low on units with 

scroll compressors. 

51/95 Unistat 290w: Low temperature stage cool not be precooled in the required 

time. Possible causes: 

-evaporator and condenser pressure sensors defect? 

-High temperature stage to weak or poorly cooled? 

51/96 Controller-EPROM: Sumcheck error. The installed EPROM has not been 

correctly programmed or it has lost some of its programming. Install a valid EPROM set. 

51/97 Cooling water controller temperature over +130°C (only CAL4, T326/7). 

Possible cause: SolidState-Relay controlling the heater cartridge could be defect. 

51/98 Unistat 420w: Gas Discharge Thermostat HT-Stage has tripped 

51/99 Unistat 420w: Gas Discharge Thermostat MT-Stage has tripped 

51/101 Motor rated circuit breaker Q1 has tripped 




51/107 HD-Pressure switch VDS 2 has tripped 

51/108 Level problem in oil separator 

51/110 Motor rated circuit breaker VDS 1 has tripped / 10 sek. main switch OFF 

51/111 Motorschutzschalter VDS 2 / 10 sek. main switch OFF 

51/112 Motorschutzschalter VDS 3 / 10 sek. main switch OFF 

58



51/113 Oil flow switch in VDS 1 has tripped 



51/116 HD-Pressure switch VDS 3 has tripped 

51/117 K22 stuck 

51/118 K22 not pulled in or dropped out 

51/121 K5 stuck 


51/123 K30 stuck 


51/125 K31 stuck 


51/127 K32 stuck 


51/129 K33 stuck 


51/131 K1 stuck 


51/133 K21 stuck 


51/135 K70 stuck 


51/137 K70 / K71 stuck 

51/138 K70 / K71 not pulled in or dropped out 

51/139 K73 / K74 stuck 

51/140 K73 / K74 not pulled in or dropped out 

59



51/141 Discharge temperature VDS 1 exceeded 



51/171 Code reduction: This EPROM can not be used with unistat 420! 


51/173 Code reduction: This EPROM can not be used with unistat 16X! 

51/174 Code reduction: This EPROM can not be used with unistat 14X! 


51/176 Code reduction: This EPROM can not be used with 15X! 

51/177 This unit cannot work with the inserted standard EPROM-set. 

You need special T32X-EPROMs. 

51/178 The EPROM set in the Controller is only suitable for T32X-models. 

Probably the wrong EPROMs were inserted at an update. 

51/180- 51/244 Invalid PLC(A3) code sent to controller. 

∗): All errors relating to an over current relay, it is advised to check the electrical 

compartment in the back of the unit (under the red/yellow main switch), to see if the 

over current relay has actually tripped. Especially after being transported it can happen 

that the auxiliary contact which is supposed to report the tripping, has been bumped 

out of position. In this case it is enough to press the reset button on the over current 

relay. But if the relay has actually tripped, there could be two causes. One could be 

the over loading of the compressor or pump and the other could be the failure of one 

phase in the three phase current supply. 

52/: 

Controller reset. Describes the internal condition of the electronic controller. 

53/: 

Valve reset. Additional closing steps were given to the expansion valve from the controller. 

If this message appears more often, this indicates a possible gradual failure of the valve 

motor. An occasional appearance is not important. 

54/: 

Only appears in connection with PC control (‘remote’ – mode, see Appendix C) of the unistat 

control. Tempering onto the second set point value, because the watchdog refreshing impulse 

from the PC has failed. Earlier the option in program 45 was selected. 

Now turn off the watch–dog (program 45 option ) or make sure the PC sends the 

watch–dog refreshing impulse in time (so the ASCII sign No 127 ‘DEL’, 7F hex according to 

hexadecimal). 

60



55/: 

Only happens in connection with PC control (‘remote’ mode, see Appendix C) of the unistat 

control. Tempering was stopped, because the watch–dog of the PC failed. The option 

in program 45 was previously selected. Either switch off the watch–dog (program 45 option 

) or make sure your PC sends the watch-dog in time (so the ASCII sign no 127 ‘DEL’, 

7 hex according to hexadecimal). 

60/: 

Controller messages and also warnings, which do not lead to a safety switch off. These 

controller messages are to be analysed with program 10. A controller message from the 

above type always starts with code number 60. Followed by /X. The index X offers you an 

exact explanation of what is happening together with the date and the time. 

Example: The message 60/45 tells you about the responding of the dry protection in the 

circulation pump. 

60/30..60/35 Initializing tests were not passed the first time, so they were repeated. 

Of no great meaning, if this only appears every now and again. 

60/45 The circulation pump is in danger of running dry: at the start of tempering 

with green key it was not possible to build up a stable fluid circulation. Cause/ 

action: see message 41/0. 

60/161Be aware of calcium build up, please decalcinate according to manual 

60/170 ECHOFAIL 

60/180 (only in IC400!): Warning K1_K1A 

60/181 (only in IC400!): Fan has failed 

60/182 (only in IC400!): K2 has not switched 

60/183 (only in IC400!0: K3 has not switched 

60/184 (only in IC400!): K4 has not switched 

61/ : 

Correction values in parameter memory for the external Pt100 sensor was set to 0. 

62/ : 

Correction value in parameter memory for the internal Pt 100 sensor was set to 0. 

63/ : 

EPROM bank 0 error 

64/ : 

EPROM bank 1 error 

65/ : 

Fault value as HT set temperature in EEPROM 

61

66/ : 

fault value as purging pause in EEPROM 

67/ : 

Fault value as compressor status in EEPROM 



68/ : 

No current in analogue interface (monitoring program 47 activated) 

69/ : 

No unit recognition read, the unit was switched on with an existing fault status. The index X 

is the same as for code 51/X. Please check the above and try to solve the problem and 

restart again. 

70/ : 

Program 180 was changed 

71/ : 

Only UNICAL: An invalid heat limit was set 

72/ : 

Program 181 was wrongly set 

73/ : 

Pt100 external is measuring higher temperatures than allowed by program 106. 

74/ : 

Pt100 external is measuring lower temperatures than allowed by program 107 

75/ : 

Error in special set of parameters for UNISTAT XL (XL_power- or XL_timer-programing). 

The false value is now considered the default value. 

76/ : 

Error in special set of parameters MODBUS software (Modbus address). The false value is 

now considered the default value. 

77/ : 

Error parameter 'Coolingpower' see program 75. The false value is now considered the 

default value. 

78/ : 

Flow temperature has exceeded the value permitted by program108. 

79/ : 

Flow temperature is lower than the value permitted by program 109. 

80/ : 

Error in special set of parameters IBI: Purging time is now considered the default value. 

93/ : 

Watchdog Event occurred. 

62

99/ : 

The password X was set 



100/ : 

Control panel EPROM version is not compatible with controller EPROM version 

101/ : 

Initialization of the control panel was made (see prog. 52 ). 

118/: 

118/n Delta-T-Band exceeded - disturbance! 

n= 1 T-internal too high 

n= 2 T-external too small 

151/ : 

Warning: Data traffic was temporarily interrupted in the control panel 

152/ : 

like 151/X error at RS232... 

154/ : 

Superheat temporarily uncontrolled 

156/ : 

suction pressure temporarily dropped 

157/ : 

Setting of compressor automatic functions (program 35) was changed. 

158/ : 

Measured JACKET TEMPERATURE has not been refreshed. Program 68 has been set to 

default 

159/ : 

Measured REACTOR TEMPERATURE has not been refreshed. Program 69 has been set to 

default 

159/ : 

Watchdog Event occurred status of thermoregulation changed. 

164/ : 

only with Cryo Coma: level dropped in expansion vessel. 

165/ : 

Controller has executed Reset. 

63


Appendix C - PC communication and remote control 

Appendix C -- PC/PLS data communication 

Professional programmers should turn to us with the protocols, before creating a software. 

You will be issued with additional information which will allow you to achieve optimal data 

communication. 

There is a large range of possibilities in communication with unistat control. The following 

criteria must be fulfilled for a serial data transmission of any kind: 

• Connect a Huber – data transmission cable (Order No 6146 from point to point, 

connection of one unit with one PC in RS232 format) to the serial interface of your control 

unit 

(Plug 12, see fold out diagram) and connect this with a serial interface (COM 1..4) to a 

PC. An adapter may be necessary if the interface on the PC has a 25 poles DSUB plug 

connector instead of the required 9 pole. This adapter can be purchased in any computer 

shop. 

• If the cable is to be made up please note the following: Please use 3 core screened cable, 

the screen IS TO BE CONNECTED AT THE PC SIDE. In the PC side the hand shake 

connection must be bridged (9 pin connection: 4 – 6 and 7 – 8). If this is not done, poor 

data transmission quality and fluctuations in temperature measurements will be the result. 

(because of the formation of earth loops) We advise you to use an original HUBER cable. 

• The interface of the PC is not allowed to be used in another way, or through a track ball, a 

modem or similar. It can lead to a conflict if the same interrupt (IRQ3 or 4) is used by two 

interfaces at the same time (unistat control on COM3 and the mouse on COM1). If 

problems of this kind arise the PC should be reconfigured accordingly. 

• As connected components must have the same data transmission rate (‘Baud rate’). In the 

unistat control this can be changed with program 85. Default 1200 Baud. 

• The general data format: 8 data bits, 1 stop bit, no parity, no hand shake 

• Specialist software is required which can deal with the protocol forms. Maybe you can 

write this software and use it with the information in this part of the manual, the program 

explanations and the given notes for data and number formats. Tip: Tempering processes 

are not very time critical. So for example use 5 seconds as a timing interval to read a 

complete data set. This way the data density is minimised and the possibility of timing 

errors in your software reduced. 

• For bus connections of more units and a PC use the RS485 standard, which can be chosen 

with program 86. 

A short overview of the functions available: 

• (1) A 'readable' Protocol for bidirectional data transmission via a point to point 

connection (see Appendix E). 

• (2) A 'secure' Protocol for bi-directional data transmission for bus communication 

(see Appendix F). 

• Passive: The PC receives data, which is produced in the control unit and kept at the 

ready for access through keyboard input on the control unit. With this goes: the 

standard protocol (program 40, to be switched off with program 41), the 

command ‘Display copy’ (program 43). 

• Remote: This function is not intended for new development work. 

64

Appendix D -- interface specification 


Appendix D - interface specification 

! Important note: 

The different interfaces are explained in this chapter, which exist in the unistat 

control. The following principles should be followed for the electrical connection of 

interfaces: 

1. Before every connection of cables are all units involved to be switched off. 

2. The plug connectors have to be checked for anything unusual before connection. 

3. Never use force to make an electrical connection. 

Some connection plugs look very similar, but are not the same. The reason for a problem 

could be just one pin that is bent. The user interfaces of unistat control are using different 

plug connection types, with this a mix up is avoided. 

The following principle is valid: Only low voltages are allowed to be connected to the 

unistats. Never use an external sensor without screened cable. The danger is that the sensor 

charged with static electricity. The Stored charge on the sensor would damage the measuring 

devices. 

Plug connection views (from above): 

Stv6 Stv7 

level 

Pt100 external 

3 

2 

1 

2 

3 

1 

4 

Stv12 RS232 

5 4 321 

9 8 7 6 

65 

Stv4 Stv5 

external 

Poko Control signal 

1 

2 

3 

1 3 

Pin 1: level test Pin 1: I+ Pin 1: mass (AGND for AIF) Pin 1: Closer Pin 1: control + 

Pin 2: level - Pin 2: U+ Pin 2: data entry (RXD) Pin 2: Middle contact Pin 2: control - 

Pin 3: level + Pin 3: U- Pin 3: data exit (TXD) Pin 3: Opener 

Pin 4: I- Pin 4: current entry for AIF (14-24V DC) 

(four core format) Pin 5: mass (DGND) 

Pin 6: 120Ω connection resistance 

(R is connected on one side to PIN 8) 

Pin 7: -A (RS485) 

Pin 8: -B (RS485) 

Pin 9: current exit for AIF 

(Please note the pin arrangement of Stv12is not as a standard PC port) 

See the view of the plug connector of the POKO and the release signal in the unit user 

instruction! 

2

D.1. RS232 interface (on Plug Stv 12) 

Documentation: Pin 2 data entry (RXD) 

Pin 3 data exit (TXD) 

Pin 5 mass (DGND) 



Use: 

The control panel has a serial interface ‘RS232’ as has the PC (COM – interface). The RS232 

interface of the control panel is equipped to send and receive (full Duplex). It is possible to; 

interrogate the unistat or Unichiller in to automating processes; to use it via a computer or to 

record an event log, with the appropriate software. See Appendix C for application 

possibilities, data format, baud rate and so on. 

D.2. RS485 interface (on Plug Stv 12) 

Layout: Pin 7 -A (RS485) 

Pin 8 - B (RS485) 

Pin 5 Ground (digital) 

Pin 6 120Ω connection resistance (R is connected on one side to PIN 8) 

Please note: In case the control unit is the last (or only) user of a bus, PIN 6 has to be bridged 

with PIN 7, so that the necessary bus connection is made. If this is not done, the data 

transmission can be prone to errors. 

Application: 

The RS485 interface is a serial, bus capable half duplex data connection. It is used when 

more ‘intelligent’ laboratory units are connected with one another (as opposed to the point to 

point connection of the RS232, the PC can exchange data with only one unistat). The RS485 

is an interface with which many units can be operated, like a multi plug. See Appendix C. 

D.3. External Control Signal (‘release’, Plug Stv 5 at the unistat) 

Pin 1 control + 

Pin 2 control - 

If the control signal is to be activated both signals ‘control +’ and ‘control –‘ must be 

connected to the same voltage of 14V…24V. The same voltage must be available for the 

controlled unit. Here goes the ‘working current principle’, this means that an additional 

function is requested, if the voltage is not there, check the instructions of the unistat model 

for the plug connector (often on the back of the unit casing). 

The following functions are to be set for this signal using program 28: 

D.3.1 ‘OFF’ 

That means there is no reaction to the switching off of the voltage. This is a pre set 

condition. 

66

D.3.2 ‘Pause / Stop’ 



This function can be changed as often as required, although it is dependent on the work 

mode. It is to differentiate: 

D.3.2.1 A thermoregulation program is running: 

As long as the release voltage is connected, the normal function is guaranteed. The UNISTAT 

goes into the condition ‘waiting’ if the voltage is not present at the, above mentioned, 

connector. The running time for the tempering program is stopped. The duration of the 

current segment is extended. The tempering is run by the current set point value. This makes 

it possible to react to certain conditions of the connected experiment. 

D.3.2.2 Normal Thermoregulation: 

In his case the tempering and the circulation are set, as long as the release voltage is not 

present. 

D.3.2.3 A control computer has taken over the control: 

The signal does not influence the working mode. The computer can question the condition 

and has the ability to react. 

D.3.3 ‘Second Set Point Value’ 

With this function it is possible, due to the external control signal, to head for a second set 

point value. It is tempered up to the ‘second set point value’ as long as the release voltage is 

not present. 

D.3.4 ‘Switch from Internal ↔External’ 

In response to the control voltage the tempering method is switched. 

With control voltage: Internal 

Without control voltage: External 

The setting via program 3 does not work, as long as this mode is chosen! 

After the ‘internal/external’ function is ended the pre set tempering method (program 3) does 

work again. 

D.3.5 Analogue Port Tint ↔ Text 

Depending of the control voltage, the internal (Tint) or the external (Text) exit is sent to the 

analogue port. 

With control voltage: Tint → AIF 

Without control voltage: Text → AIF 

D.3.6 Stand by 

The tempering is started via the release signal. As soon as the release signal is switched off, 

the tempering is interrupted. 

67

D.3.7 SP SWITCH 



Thermoregulation at two different temperatures by switching the release signal. 

D.4. Potential (volt) Free Contact (POKO, plug connection Stv 4 at unistat) 

Pin 1: Closer 

Pin 2: Middle contact 

Pin 3: Opener 

The POKO is a switch contact of the POKO relay in the controller. The potential free contact 

is suitable for a resistive load up to 30V and maximum 0,1A. Because of the working current 

principle: The OK condition is connected with the POKO relay by the current going through 

the winding. The POKO relay is controlled by the controller. 

The POKO function can be selected with program 8: 

D.4.1 POKO ‘OFF’ 

The POKO displays the OK condition, if the unit is ready for use. This condition is present 

after 30 seconds, after the internal controller check has been completed. (Default setting) 

D.4.2 POKO ‘actual value check’ 

A temperature range around the set point can be set with program 6 and 7. 

The potential free contact reports the condition, if the actual value is outside the temperature 

range. If this set range is exceeded, the potential free contact switches, there is no other 

reaction of the unistat. If the actual value returns to within the range, the contact is switched 

back (OK condition). 

Example: POKO Actual Value Check has been activated and external tempering is being 

carried out. POKO max has a limit of 5K above the set point value, set with program 6. POKO 

min is given as 7K below the set point value using program 7. At this time the set point value 

is 27,5°C. The contact switches if the external sensor measures more than 32,5°C or 

less that 20,5°C. 

It depends on the tempering method weather the internal or the external sensor is used. 

D.4.3 POKO ‘External Alarm’ 

In this function the POKO relay is only active if the unit goes into a ‘fault’ condition. 

The working current principle does not exist here. The advantage of this is that the alarm is 

not raised when the unit is switched off. If the alarm function is required together with the 

working current principle, use function ‘OFF’ (s. 1.). 

D.4.4 POKO ‘UNIPUMP/ PLS’ 

If a Unipump is used in the thermofluid circuit, this POKO function is programmed to signal 

the external pump to run, so that the external pump is synchronised with the circulation 

pump of the unit. The POKO is active at the same time as the internal circulation pump is 

switched on. 

68



PLS: 

(Same as Program 8, Option 3) PLS stands for „Prozess Leitsystem“ (English-Process Control 

System), this mode is often used when the unistat is integrated in a „PLS“. 

An example of this would be when the unistat would be controlled via a „PLS“ via the 

external control signal (Program 28 Option 5), the POKO can also be used to communicate 

the status of the unistat to the PLS. 

Condition POKO ON means thermoregulation is activated. 

Condition POKO OFF means thermoregulation is not activated. 

D.4.5 POKO ‘TP spur [1]’ 

This function activates the POKO only if a tempering program is running and is processed via 

a POKO-spur—segment chosen with program 26. 

D.4.6 POKO ‘TP spur [2]’ 

Functioned as explained under 5., but the POKO is active for the rest of the tempering 

program. Note: The POKO function can be re programmed while the tempering program is 

running. 

D.4.7 POKO ‘Extern’ 

The POKO is set or reset via the RS232 interface. Use: PC software UNISTAT 

PROGRAMMER version 2. 

D.4.8 POKO ‘UNIPUMP with Echo’ 

This is a further sophistication of the function D.4.4. The feed back contact of the 

'UNIPUMP' is monitored. A fault would be triggered if the UNIPUMP does not operate in 

synchronisation with the circulation (see Paragraph D.7.). 

D.5. Analogue interface 4..20 mA 

AIF on Plug Stv 12, from control unit version 3.0 or later 

Layout: Pin 4: current entry 

Pin 9: current exit 

Pin 1: mass (AGND) 

Application: 

• This port can be used to externally give a set point value or to directly enter the power of 

the refrigeration machine or the heater. This function is activated with program 46. The 

setting of the current/temperature relationship and the limits is done with program 135 and 

137. A simple smoothing filter can be activated with program 140. 

• This port can have more uses: internal and external actual value, the set point value (for 

fast calibrating) or difference of two given signals. The port is assigned a function with 

program 138, to be set with program 136 and 137. 

69



The 4..20mA port has got a limit of the connected resistance of 250Ω. The interface changes 

the current range from 4..20mA into a voltage surge of 1..5V. The entry contact 4 can be 

used also as a high resistance port. For this the (only) jumper is to be put into the park 

position in the control unit. The 4..20mA port produces a load resistance of 250Ω at a 

voltage of 1..5V. 

Note: The load resistance of the connected device may not be higher than 250Ω. 

An advantage is in the free choice of the range limits. The measuring range of 

-20°C..+200°C or from +15°C..+25°C can be set. Because the range of 4 – 20mA is 

used, the +15°C..+25°C temperature range are more accurately measured (higher 

resolution). 

Note: The activation can be refused if another function is influencing the set point value 

already. The PC control should also be considered. 

The condition set with program 46: 

AIF:OFF 

Is related to the processing of the entering current. In this condition the entry current is 

ignored. The exiting current can, for example be used for writing a log. 

The condition: 

AIF → SP 

Is related to the processing of the entering current to the given set point value. The 

programming AIF--->SP is refused, if the set point value is already taken from another source 

(for example a tempering program, ramp, RS232/RS485 interface). If the AIF should be 

activated despite this, a note on the activated set point value source will appear. 

D.6. Pt100 external 

(Plug Stv 7, at top of unistat control) 

! Warning: The unit will switch off with the fault message 46/2 if anything other than 

an original Huber sensor, and this is a fault is the plug layout or the 

characteristics. 

Layout: 

Pin 1: I+ 

Pin 2: U+ 

Pin 3: U- 

Pin 4: I- 

1: I+ 

2: U+ 

PT 100 

70 

4: I- 

3: U-



Application: 

It can be connected with an external temperature sensor (Pt100 in four core arrangement). 

This is needed if the temperature in an external vessel is to be measured. This measuring 

value is then used as the actual value for the controller (external tempering method, program 

3), this is used to keep the temperature constant in the connected vessel. The simple 

variation is the ‘internal’ tempering method without external sensor only keeps the 

temperature constant at the pump exit of the unit, fast temperature change (like exothermic 

in a tempered reactor) might be recorded with a time delay and some adjustment may be 

required. 

D.7. External level monitor 

(Plug Stv 6, top left at unistat control) 

! Important: Avoid at all costs, wrongly installing a monitor, that no voltage is applied to 

this port of the unistat control or that this port is short circuited. If possible 

use level monitors from the Huber range. 

Layout: Pin 1: level test (bridges with contract 2 - 'Present') 

Pin 2: level - (GND) 

Pin 3: level + (closer) 

Application: 

A sensor can be connected to monitor the liquid level in an external tempering bath. 

As soon as the liquid level falls below the set level the sensor responds (opens), it releases an 

‘emergency off’. The tempering and the circulation are stopped immediately. This allows 

(together with installed over temperature protection) an unsupervised operation in protection 

class 2. 

Unistat control recognises automatically, if the optional level monitor is installed. An 

externally connected level switch (Plug Stv6) has to be installed as follows: 

1. Contact 1 has to be bridged in the plug with contact 2 for the connection of a level 

monitor to be recognised. 

2. The level switch is connected to contacts 2 and 3. The switch must be fitted in such 

a way that it opens if the level has sunk. 

If the function 'UNIPUMP with ECHO' as described in D.4.8. is required, an auxiliary contact 

from the Unipump contactor in lieu of the level switch must be connected. The bridge in the 

plug between contacts 1 and 2 must be present. 

D.8. Plug Connection unistat control control unit 

After removing the control the two 9 pole DSUB connectors Plug Stv11 (at the control unit) 

and Plug Stv8 (at housing of unistat control) are visible. A cable (order no 6147) can be 

connected between these two so the control unit can be operated away from the unit. 

D.9. Plug Connection unistat control unit 

Base left Plug Stv 9 small voltage signal to UNISTAT 64 contacts 

Base right Stv 10 mains voltage signal to UNISTAT 32 contacts 

71


Appendix E – PP – command set for RS232 

Appendix E -- PP - command set for RS232 

‚PP‘ is for ‚Point to Point‘. These commands are for the „classic“ data communication unistat- 

PC. The PP-Commands are intuitively readable. The description of the commands are in two 

sections. The first section are the Compatible commands, and in the second section are the 

commands exclusive to the Unistats. 

Protocol setting for the PP commands 

Baud rate 1200, 2400, 4800, 9600 asynchronous 

Start bit 1 

Data bits 8 

Parity none 

Stop bit 1 

The following values are available: 

Set value in 1/100K from the PC to the Control Panel: 

-##### # stands for a digit 0-9, 

- stands for a negative prefix (+ optional). 

e.g. +1000 (10°C), -123 (-1.23°C), +12345 (123.45°C) 

Set value or actual value in 1/100K from the controller to the PC with 6 characters: 

±##### # stands for a digit 0...9, 

± stands for a prefix + or - 

e.g. +01000 (10°C), -00123 (-1.23°C), +12345 (123.45°C) 

The description of commands corresponds to the chart: 

Description 

Command [number format] Response [number format] 

Comments, Examples Storage Compatible 

A flexible command interpreter was used for some commands. This enables the programmer 

to use a command in a different way. These commands are marked with a @ (for echo) after 

the command. These commands may be used as setting commands; interrogation commands 

or setting commands with echo commands. An example: 

SP@ -##### [2] SP ±##### [4] 

Set set value with echo volatile yes 

This command may be used in three variants for example: 

Set value from the PC to the control panel/controller. 

SP -##### [2] none 

Are given in 1/100K, eg 

SP 10000 for +100°C, SP - 

120 for –1.2°C 

72 

volatile yes 

Set value from the control panel/controller to the PC 

SP? SP ±##### [4] 

In 1/100K with prefix and leading zeros, eg SP -00123 

for 1.23°C. 

- yes



Set value from the PC to the control panel/controller, echo from the control panel/controller to 

the PC. 

SP@ -##### [2] SP ±##### [4] 


We strongly recommend to use the ECHO, because in Echo there will be no timing problems 

with recovering times. Not the recovering period means ignoring the following strings. 

The following commands described as compatible are also available for the HUBER CC 

thermostats in the Unistat Control from V3.7. This makes it possible to write programs which 

can function both on all CC thermostats from V3.04 as well as all unistats from V3.7. 

However, here the different time response of the thermostats should be taken into account. 

For example, the power up operation takes different lengths of time and so the response to 

the command KM? is not identical. A test run on both equipment types is 

essential. 

Set value and set value restrictions, actual values 

Set value from the PC to the controller, echo from the controller to the PC. 

SP@ -##### [2] SP ±##### [4] 


Set value restrictions from the PC to the controller, echo from the controller to the PC. 

LL@ -##### [2] LL ±##### [4] 

LL@ 500 For low-limit 5°C permanent Yes 

LH@ -##### [2] LH ±##### [4] 

LH@ 09520 For high-limit 95.2°C permanent Yes 

Minimum Set Point adjustment (unit specific). 

This temperature is therefore the minimum limit for the 'LL'-Command 

TL? TL ±##### 

In 1/100K with + or – and zeros in front, e.g. 

TL -04500 für UNISTAT TANGO 

- Nein 

Maximum Set Point adjustment (unit specific). 

This temperature is therefore the maximum limit for the 'LH'-Command 

TH? TH ±##### 

In 1/100K with + or – and zeros in front, e.g. 

TH +20000 für UNISTAT TANGO 

- Nein 

Internal temperature from the controller to the PC. 

TI? TI ±##### [4] 

In 1/100K with prefix and leading zeros, eg 

TI +00100 for 1.0°C 

- Yes 

External temperature from the controller to the PC 

TE? TE ±##### [4] 

In 1/100K with prefix and leading zeros, eg 

TI -00100 for -1.0°C 

- Yes 

73



Change external set value to interface 

With the „CETM„-command the source of the external actual value of the Pt100 can be 

changed to the serial interface. After switching a new external actual value has to be 

continually transmitted. This is done with the „RTE„-command. 

CETM_ON@ 

CETM ON or 

CETM_OFF@ 

CETM OFF 

CETM_ON = switch on TempMove 

without echo 

CETM_OFF@ = switch off TempMove 

with echo 

CETM? = interrogation of TempMove- 

Status 

Volatile Yes 

Command to transfer the external temperature through the serial interface. A new 

external actual value must be received, otherwise the fault 159/0 will be triggered. 

RTE@ -##### [2] RTE ±##### [4] 

RTE@ 00100 = setting the external 

temperature to 1°C with Echo 

RTE 01000 = setting the external 

temperature to 10°C without echo. 

RTE? = interrogation of temperature . 

Volatile yes 

Change internal set value to interface 

With the „CITM„-command the source of the internal actual value of the Pt100 can be 

changed to the serial interface. After switching a new internal actual value has to be 

continually transmitted. This is done with the „RTI„-command. 

CITM_ON@ 

CITM ON or 

CITM_OFF@ 

CITM OFF 

CITM_ON = switch on TempMove 

without echo 

CITM_OFF@ = switch off TempMove 

with echo 

CITM? = interrogation of TempMove- 

Status 

Volatile no 

Command to transfer the internal temperature through the serial interface. 

Command to transfer the internal temperature through the serial interface. A new internal 

actual value must be received, otherwise the fault 158/0 will be triggered. 

RTI@ -##### [2] RT ±##### [4] 

RTI@ 00100 = setting the external 

temperature to 1°C with Echo 

RTI 01000 = setting the external 

temperature to 10°C without echo. 

RTI? = interrogation of temperature . 

Volatile no 

Alarm messages 

Request device status 

ERROR? ERROR # 

# = 0 = no error, # > 0 = error - yes 

74

Control mode 



Set internal temperature control mode 

INTERNAL@ INTERNAL ON 

Set and request temperature control mode. INTERNAL? 

See above 

permanent yes 

Set external temperature control mode 

EXTERNAL@ EXTERNAL ON 

Only with connected Pt100, otherwise Response = 

INTERNAL ON. EXTERNAL? see above 

permanent yes 

Request temperature control mode 

TEMP? INTERNAL 

EXTERNAL 

Response dependent on the temperature control mode 

(see §1.3) 

- yes 

Switching temperature control on and off 

With the Unistat and Ministat CC, the heating, compressor and the pump are switched on or 

off. 

With the Compatible Control and Unichiller Control, the heating and the compressor are 

switched off, the pump continues to run. These commands should not be used too often as 

the compressor must not be switched on and off too frequently. 

Switching on temperature control 

KM_ON none 

Only switching on. permanent yes 

KM_ON@ ON 

Switching on and echo. permanent yes 

Switching off temperature control 

KM_OFF none 

Only switching off permanent yes 

KM_OFF@ OFF 

Switching off and echo. permanent yes 

Requesting temperature control 

KM? ON 

OFF 

Only echo. - yes 

75

Handling the floating contact (POKO) 



To switch the floating contact via the RS-interface, it is first necessary to set the POKORS 

mode to ON with the POKORS commands. In POKORS mode OFF, the POKO commands are 

ignored, but the POKO? command returns the current POKO status. When the power is 

switched on, the POKO remains in the current status, when it is switched off the controller 

determines the POKO status. 

Determining POKORS mode 

POKORS_ON none 

Handling POKO via the interface permanent yes 

POKORS_ON@ POKORS ON 

Handling POKO via the interface with echo. permanent yes 

POKORS_OFF none 

Handling POKO from the controller permanent yes 

POKORS_OFF@ POKORS OFF 

Handling POKO from the controller with echo permanent yes 

POKORS? POKORS ON 

POKORS OFF 

Request POKORS mode. - yes 

Handling POKO 

POKO_ON none 

Switching POKO on volatile yes 

POKO_ON@ POKO ON 

POKO OFF 

Switching POKO on with echo volatile yes 

POKO_OFF none 

Switching POKO off volatile yes 

POKO_OFF@ POKO ON 

POKO OFF 

Switching POKO off with echo volatile yes 

POKO? POKO ON 

POKO OFF 

Request POKO - yes 

76



Watchdog 

The watchdog is a security installation allowing the surveillance of the communication 

between thermostat and PC. In order to activate the watchdog, a WDx-command 

together with a time indication has to be sent to the thermostat. Within this time, the 

command has to be refreshed, otherwise, the watchdog executes his action. Taking the 

WD1-command, the watchdog switches off thermoregulation, an error message is 

displayed. Taking the WD2-command, the watchdog replaces the set value by the 2 nd set 

value, to which the thermostat then adjusts. A warning is displayed. A WDx-command 

with time = 0 deactivates the watchdog. 

Watchdog in mode 1 = set switch off. 

WD1@ %%%%% [6] WD1 +##### [4] 

Set watchdogmode 1 (switch off) with echo volatile yes 

Watchdog in mode 2 = set 2 nd set-point value. 

WD2@ %%%%% [6] WD2 +##### [4] 

Set watchdogmode 1 (switch off) with echo volatile yes 

Keypad: 

The following commands control access to the keypad. 

REMOTE-Modus activated 

REMOTE None 

Keypad Locked volatile yes 

Set point from PC to Controller, Echo from Controller to PC. 

LOCAL None 

Keypad Unlocked volatile yes 

Diverse 

Device code 

With this command the device code is read out. 

The command „DSPY 49„ is basically compatible to all units, the answer 

however depends on the unit. 

DSPY 49 0x0c 32Byte 

UNISTAT TANGO -40 to 200°C yes 

Software Version Number 

This command is used to read the software version. The command 

„DSPY 98 “ gives two version numbers, the first being the control panel 

software and the second being the controller software. The data is presented in the 

following format: 

4 character version number followed by a 10 character date and time. 

DSPY 98 0x0c 32Byte 

V3.7 1703011200 V3.7 1404011330 

77


Appendix F - LAI Command Set for RS485 

Appendix F -- LAI Command Set for RS485 

The LAI Command Set is for controlling several units from a PC via an RS485 Bus. 

The transmission of data is more secure than with the PP- Command Set. 

General: 

The master unit transmits to the slave unit and always receives an answer (echo). 

No slave unit transmits unless prompted. 

This procedure is upper and lower case sensitive. 

Numerical values are transmitted as hexadecimal numbers in two’s complement notation. 

As a result each Byte is represented by 2 ASCII characters. The decimal number 100 

corresponds to the hexadecimal number 64h therefore the ASCII characters ‘6’ and ‘4’ are 

transmitted. The decimal number -100 corresponds to the hexadecimal number 9Ch therefore 

the ASCII characters ‘9’ and ‘C’ are transmitted. 

Temperatures are transmitted with a resolution of 0.01K, i.e., +100°C corresponds to the 

decimal number 10000 and the hexadecimal number 2710htherefore the ASCII characters 

‘2’, ‘7’, ‘1’, ‘0’ are transmitted. The temperature -100°C corresponds to the decimal number 

-10000 and the hexadecimal number D8F0h therefore the ASCII characters ‘D’, ‘8’, ‘F’, ‘0’ 

are transmitted. 

The ASCII characters ‘0’...’9’ and ‘A’...’F’ are used when transmitting numerical and 

temperature values. 

A request from the master to the slave is constructed according to the following assignment: 

‘[mssilld...dpp\r’. 

This includes: 

[ Start character 5Bh 1 Byte 

m Transmitter ID M = Master 4Dh 1 Byte 

ss Slave address 00..99 2 Byte 

i Data group identifier 1 Byte 

ll Length of the data field 2 Byte 

d...d Data group 0...50 Byte 

pp Checksum 2 Byte 

\r End character CR 0Dh 1 Byte 

An answer from the slave to the master is constructed according to the following 

assignment: ‘[mssilld...dpp\r’. 

This includes: 

[ Start character 5Bh 1 Byte 

m Transmitter ID S = Slave 53h 1 Byte 

ss Slave address 00..99 2 Byte 

i Data group identifier 1 Byte 

ll Data field length 2 Byte 

d...d Data groups 0...50 Byte 

pp Checksum 2 Byte 

\r End character CR 0Dh 1 Byte 

Characters which precede the checksum are described as the data field. 

Characters following the 7 th Byte and preceding the checksum are described as the data 

group. The actual data is contained within the data groups. The meaning of the data is 

indicated using an identifier. The commands are designated according to the ID in the 

following. 

78



A checksum is transmitted in order to improve data security. The checksum is the 1-Byte 

sum of all hexadecimal values from the start character up to the last character before the 

checksum. 

Example: The master transmits: ‘[M01V07C6\r’ 

ASCII Hex Meaning 

1 st Byte [ 5Bh Start character 

2 nd Byte M 4Dh Transmitter ID M = Master 

3 rd Byte 0 30h Slave address 01 

4 th Byte 1 31h Slave address 01 

5 th Byte V 56h Data group identifier 

6 th Byte 0 30h Length of the data field 07 Byte 

7 th Byte 7 37h Length of the data field 07 Byte 

8 th Byte C 43h Checksum C6 

9 th Byte 6 36h Checksum C6 

10 th Byte \r 0Dh End character CR 

The length of the data field is the number of Bytes preceding the checksum. 

The checksum is created using these Bytes. 

5Bh+4Dh+30h+31h+56h+30h+37h = 1C6h --> 1Byte-Summe = C6h. 

Protocol setting for the LAI commands 

Baud rate 1200, 2400, 4800, 9600 asynchronous 

Start bit 1 

Data bits 8 

Parity none 

Stop bit 1 

The following commandsform part of the Compatible Command set and are valid for all Huber 

controllers with an RS232/RS485 interface. 

In the examples, slave 01 is always the subject of interrogation. 

Additional special commands are possible. They are described in the controller manual. 

´V´ Verify Provided to check if a slave is present. The command is not assigned a 

data group. 

Master enquiry: ‘[M01V07C6\r’ 

The master enquires whether the Slave 01 is connected to the bus. 

Slave reply: ‘[S01V0EMINI CCAD\r’ 

Slave 01 is connected to the bus and the device is a ministat CC. The 

command has the data group ‘MINI CC’. This is 7 Byte long. These 7 

Bytes added to the 7 Bytes from the data group result in a data field 

length of 14 Bytes = 0Eh Bytes. 

79



‘G’ General This command communicates the most important temperatures and 

status information. 

A modified set-point value is not stored in the permanent memory, i.e., 

this value is lost when the power supply is disconnected. 

Master enquiry : ‘[M01G0Dsattttpp\r’ 

s = Temperature control mode: 

‘C’= Circulation activated. Is ignored by CC 

thermostats. 

‘E’= Activate external temperature control. 

‘I’= Activate internal temperature control. 

‘O’= Off, Deactivate temperature control. Is ignored by 

CC by thermostats. 

‘*’= Do not change the current status. 

a = Reset alarm 

‘0’= No alarm reset. 

‘1’= Any activated alarm is reset. 

‘*’= Do not change the current status. 

tttt = Set-point in the temperature format described above. 

‘****’= No change of the set-point. 

pp = Checksum in the format described above. 

\r End character CR. 

Slave Reply: ‘[S01G15sattttiiiieeeepp\r’ 

s = Temperature control mode 

‘C’= Circulation activated. Not feasible for CC 

thermostats. 

‘E’= External temperature control activated. 

‘I’= Internal temperature control activated. 

‘*’= Only permitted if the status cannot be determined. 

a = Alarm status 

‘0’= No alarm. 

‘≠ 0’= A numerical value which does not equal 0 indicates 

an alarm. 

tttt = Set-point in the temperature format described above. 

iiii = Internal actual value in the temperature format described 

above. 

eeee = External actual value is in the temperature format described 

above. 



80



‘L’ Limit This command communicates the set-point limits (see §1.5 Setting the 

Internal Set-point Limit). 

Master enquiry: ‘[M01L0Fllllhhhhpp\r’ 

llll = Low limit, lower set-point limit in the above temperature 

format. 

**** = no change of the lower set-point limit. 

hhhh = High limit, upper set-point limit in the above temperature 

format. 

**** = no change of the upper set-point limit. 



Slave reply: ‘[S01L17llllhhhhuuuuoooopp\r’ 

llll = Low limit, lower set-point limit in the temperature format 

described above. 

hhhh = High-Limit, upper set-point limit in the temperature format 

described above. 

uuuu = Lower working range. This limit is specific to the device and 

cannot be modified. The lower set-point limit is not permitted 

to be lower than the lower working range limit. 

oooo = Upper working range limit. This limit is specific to the device 

and cannot be modified. The upper set-point limit is not 

permitted to exceed the upper working range limit. 



‘I’ Ident This command changes the slave address (s. §3.4 Setting device ID). 

Important! The slave address is stored in the permanent memory. This 

is limited to 100,000 overwrite cycles as a result of the components 

used. When programming, ensure that these memory addresses are 

not overwritten too frequently. 

Master enquiry: ‘[M01I09nnpp\r’ 

nn = New slave address ‘00’...’99’. ** no change of the slave 

address. 



Slave reply: ‘[S01I09nnpp\r’ 

nn = New slave address. This address is valid after the reply is 

transmitted. Was entered as new slave address ** the previous 

slave address is returned. 



If this LAI-Command set is not adequate please contact our hot line. 

81

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