Measurement and Analysis Systems Complete RAS Systems for ...

DSE02-12.04 · Complete RAS Systems · © 2004 rotec GmbH, Munich · Subject to change without prior notice 

Measurement and Analysis Systems 

Complete RAS Systems for Stationary Applications 

RAS systems combine proven rotec expertise and reliability with outstanding flexibility and ease-of-use. The customer 

may begin with a basic system comprising only a few channels and standard software before later expanding 

to a system with many channels and a comprehensive range of data acquisition and analysis software. 

The modular architecture and versatile software make the equipment suitable for a wide range of testing and signal 

acquisition tasks. 

The RAS and USA systems are ideal for test-cell and laboratory measurements. Data acquisition and analysis are 

contained in a single unit. The RAS frame can accommodate up to 8 rotec data acquisition boards, the USA frame 

up to 12. 

RAS 

◗ 3/4 19" frame, includes trigger and timing board. 

◗ Data acquisition and analysis system with 7 slots 

available for rotec data acquisition boards. 

rotec GmbH · Joseph-Dollinger-Bogen 18 · D-80807 Munich · Germany 

Tel: +49 (0) 89 323 651-0 · Fax: +49 (0) 89 323 651-56 

USA 

◗ 19" frame, includes trigger and timing board. 



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DSE02-12.04 · Complete RAS Systems · © 2004 rotec GmbH, Munich · Subject to change without prior notice 


Complete RAS Systems for Stationary Applications 

CompactPCI Technology 

◗ Mobile Pentium M CPU, 1 Gbyte RAM, hard drive, 

floppy and MO drives 

◗ External interfaces: 2 x USB2.0, 2 x RS232, 1 x 

100Base Ethernet 

(RJ45), 1 x 1000Mbit Ethernet (RJ45), VGA 

◗ Internal IEEE-1394 interface 

◗ Hinged keyboard with touchpad / trackball 

◗ TFT 10.2" colour screen (800 x 600) 

◗ Microsoft Windows XP 

◗ Operating voltages: 110 / 220 V AC, 10 – 35 V DC, 

backup battery 

◗ Switchable cooling fan 

◗ RAS dimensions 20x36x43 (hxwxd), 

approx. wt. 18 kg 

◗ USA dimensions 20x47x43 (hxwxd), 

approx. wt. 20 kg 


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RAS19" 

◗ 19" rack mount system, includes trigger and timing 

board. 



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DSE01-12.04 · Modular RAS Systems · © 2004 rotec GmbH, Munich · Subject to change without prior notice 


Modular RAS Systems for Mobile Applications 


may begin with a basic system comprising only a few channels and standard software before later expanding 

to a system with many channels and a comprehensive range of data acquisition and analysis software. 

The modular architecture and versatile software make the equipment suitable for a wide range of testing and signal 

acquisition tasks. 

RASnbk 

Analysis and control unit. Notebook electrically and 

mechanically modified. WindowsXP operating system. 

Fast, 60Gbyte hard-disk drive and CD R-W 

drive. Modem, USB, VGA, Ethernet, IEEE-1394 and 

PCMCIA interfaces. Includes rotec carrying bag for 

frontend and notebook. 


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Notebook and Frontend 

The combination of the control and analysis unit 

RASnbk and RAS frontends is particularly suited to 

mobile applications. Three sizes of frontend frames 

are available – with 4, 8 or 12 slots – for rotec data 

acquisition boards. A single cable suffices (IEEE- 

1394, length 10m) for data exchange between the 

RASnbk and the frontend acquisition unit. The flexible 

architecture allows for frontend configuration tailored 

to meet individual needs. 

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DSE01-12.04 · Modular RAS-Systems · © 2004 rotec GmbH, Munich · Subject to change without prior notice 


Modular RAS Systems for Mobile Applications 

RASFE08 

Data acquisition unit. 8-slot frontend. Includes trigger 

and timing board. 7 slots available for rotec data acquisition 

boards. 

RASnb 


and timing board. 11 slots available for rotec data acquisition 

boards. Expandable with RASnb+. 

RASFE12 


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and timing board. 11 slots available for rotec data 

acquisition boards. 

RASnb+ 

Data acquisition unit. Frontend expansion with 4 slots 

for rotec data acquisition boards. 

www.rotecmunich.de

DSE03-12.04 · RASf1 · © 2004 rotec GmbH, Munich · Subject to change without prior notice 


RASf1 – for Measurements on Racing Cars and Motorcycles 

RASf1 is a standalone system which can be used for multichannel measurement of both torsional vibration and 

analogue signals. It complies with the full software and measurement board specifications of the standard RAS 

systems. The main difference lies in the small size which, for example, allows for measurements on racing cars 

and motorcycles. 

RASf1 

The RASf1 Base Box contains the complete PC, the 

trigger board and three speed channels. A Single 

Board CPU designed for severe environments is 

used. It has no hard-disk drives. The operating system 

and RAS software are located on a Compact- 

Flash memory card. 

The acquired test data are stored on a second CompactFlash 

memory card. The software is configured 

so that the operating system loads automatically 

when powering up the system. The RAS software 

then starts and begins a measurement using the currently 

active measurement setup. Data acquisition 

can be started using the external trigger or by pushing 

a button on the remote "3-button operation" control 

unit. 

RASf1 Base Box and RASf1ana Extra Box 


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RASf1rot and RASf1ana 

The Base Box may be expanded with an Extra Box 

containing either four speed channels (RASf1rot) or 

sixteen 50kHz analogue channels (RASf1ana). Timing 

signals from the trigger board and the IEEE-1394 

connection are bussed via a flat ribbon cable. Measurement 

signals and power input are fed via a 

Canon connector. 

Base Box 

◗ Dimensions: 185x150x50mm 

◗ Weight: 1400 g 

◗ Power required: 9 to 18V, 40W 

Extra Box 

◗ Dimensions: 185x150x35mm. 

◗ Weight: 950 g 

◗ Power required: 9 to 18V, 15W 

www.rotecmunich.de

DSE14-01.05 · Torsional Vibration Module DSM2 · © 2005 rotec GmbH, Munich · Subject to change without prior notice 

Sensors 

Torsional Vibration Module DSM2 

The DSM2 (DSM = Drehschwingungsmodul) is used in the investigation and monitoring of torsional vibration emitted 

by rotating machinery. The speed of rotation must be measured with a sensor which detects at equidistant 

angular intervals around the rotating shaft and whose output signal is a square wave TTL pulse train. Suitable 

sensors are, for example, incremental rotary encoders with integrated digitizing electronics or inductive / magnetoresistive 

proximity sensors and an accompanying pulse-forming electronic unit. The DSM2 input frequency range 

is from 0.3Hz to 200kHz. 

The DSM2 determines the speed of rotation by 

measuring the periods of the TTL pulses. A fast digital 

signal processor converts these time values to 

speed or related units and outputs the data in real 

time as analogue voltages. The long wave signal 

components (= average speed) are separated from 

the short wave components (= speed fluctuation) 

and output on separate ±10V outputs, 'OUT1' and 

'OUT2' respectively. The 'OUT1' analogue output provides 

information on the mean angular velocity which 

is calculated as an arithmetic mean with unit rpm, 

rad/s, etc. A digital, low-pass filter with user-defined 

cut-off order is used. The speed fluctuation, angular 

acceleration or vibration angle may be output on 

'OUT2'. High accuracy is guaranteed for dynamic 

speed data since both of these outputs have 16 bit 

resolution. 

Output 'LIMIT' is especially useful for test-rig monitoring 

applications. The DSM may be added to the 

dynamometer control system to output an emergency 

stop signal when user-defined limiting values 

are exceeded. 'LIMIT' pre-trigger time data are saved 

internally to a 2Mb memory buffer allowing detailed 

post-process analysis using the rotec RAS software. 


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The module's settings are managed via USB interface 

and menu-driven software from an external PC 

or locally using the front panel buttons and display 

unit. 

Mechanically, the DSM2 is designed in Euro-format 

(3U) for 19" racks. Signal input and output is via the 

connectors integrated into the front panel or via the 

standard DIN connector on the module's rear. A suitable 

housing is provided with handle and fold-away 

feet. 

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Setup 

The DSM may be configured either via USB interface 

from an external PC with a menu-driven software program 

or locally using the knob, buttons and display 

unit integrated into the front panel. 

Front panel mounted controls allow for input of parameters 

such as number of pulses per revolution, 

scaling of outputs and specifying the calculations 

which are to be made. These parameters as well as 

the results of calculations are shown on the integrated 

4-line ASCII display unit. Push buttons are used to 

select the physical quantities and their units while the 

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knob is used to set their numerical values. Up to ten 

different setups may be stored in memory. 

The menu-driven software program (included) requires 

Windows 2000 or XP and a USB port. The 

software allows the user to configure parameters, install 

new firmware and store/retrieve time data in RAS 

(rotmeas) format. 

The standard RAS software is required if further 

analysis of time data is required. Full RAS Evaluation 

functionality may then be applied to the rotmeas 

measurement files.

Calculations 

All calculations may be made in radians, degrees or 

revolutions. Results are continually shown on the 

internal numerical display unit and simultaneously 

output on 'OUT1' and 'OUT2' as scaled analogue 

voltages. 

Time Domain Calculations 

Angular velocity, vibration angle and angular acceleration 

may be calculated and output. Depending on 

the ordinate, the following calculations are available: 

◗ Vibration angle 

◗ Angular velocity 

◗ Speed fluctuation (high-pass, order filtered) 

◗ Angular acceleration 

The above calculations are performed continuously, 

i.e. each pulse detected produces an updated result. 

Statistical Calculations 

Statistical and spectral calculations are performed on 

moving blocks (the block size is a finite number of 

revolutions) and may be made for each of the amplitude 

quantities listed above: 

◗ Min. Values: The smallest value in the block is 

output on both the display unit and at 'OUT2'. 

This value is retained until it is either no longer 

present within the block or the calculation results 

in a smaller value. 

◗ Max. Values: Analogous to Min. Values. 

◗ Max.-Min. Values: Corresponds to peak-peak 

calculation. 

◗ Quadratic Mean: The rms value based on the 

block size may be calculated. 

Spectral Calculations 

Order domain calculations may also be carried out. 

Discrete orders as well as order summations may be 

output. Spectra of the vibration angle, angular velocity 

and angular acceleration may be calculated. The FFT 

method is used with a maximum of 1024 data points. 

Limits 

Upper / lower limiting values of discrete orders or 

order summations may be investigated for spectra 

and, for time data, the minimum, maximum or arithmetic 

mean. All investigations may be made as a 

function of the speed of rotation as listed in a table. 

Limiting values for: 

◗ Amplitudes: Vibration angle, angular velocity, 

angular acceleration. 

◗ Spectra: Discrete orders, order summations. 

◗ Time data: Minimum values, maximum values, 

arithmetic mean. 

◗ Exceeding of upper or lower limit. 

◗ All of this applies to either the complete speed 

range or a restricted speed range 

The DSM2 is also fitted with a 'Disable' input with 

which a calculation may be stopped. This function is 

used, for example, for temporary interruption of 

calculations during mechanical switching or coupling 

operations. Both the 'Disable' input and 'Limit' output 

signals are TTL level - High or Low. 

www.rotecmunich.de

DSE14-01.05 · Torsional Vibration Module DSM2 · © 2005 rotec GmbH, Munich · Subject to change without prior notice 

Specifications 

Inputs 1 TTL and 1 incremental encoder 

www.rotecmunich.de 

Sensors 

Torsional Vibration Module DSM2 

Input frequency range 0.3 Hz to 200 kHz 

Counter size 31 bits 

Counter clock 640MHz 

TTL input 'SENSOR' For rotec Digitizer, 

one bit reserved for direction 

of rotation 

8-pin Lemosa (small) connector 

Signal type TTL 

Minimum pulse width 100ns 

Input overload protection ±35V 

Input impedance 250Ω 

Sensor supply voltages +5V, +12V 

Incremental For standard encoders incl. 12-pin connector, 

encoder input supply voltages standard pinning 

'ENCODER' Edge detection x1 

Outputs 

Direction of rotation detection 

Processing of index pulse 

Signal type TTL differential 

Standard outputs 2 identical outputs SMB connector 

'OUT1', 'OUT2' Voltage range ±10V, buffer 

Resolution 16 bits 

operational amplifier 

Settling time 10µs (max) 

Maximum output frequency 100kHz to 250kHz 

Calibration automatic at start of measurement 

Sync. output Single-channel SMB connector 

'REF' Output voltage TTL, buffered driver 

Clock output Single channel SMB connector 

'CLK' Output voltage TTL, buffered driver 

Pass / Fail output Single-channel SMB connector 

'LIM' Output voltage TTL, buffered driver 


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DSE04-12.04 · Data Acquisition Boards · © 2004 rotec GmbH, Munich · Subject to change without prior notice 

RAS Data Acquisition Boards 

Trigger, Speed, Analogue 

Trigger and Timing Board (E-TR) 

This board provides the central time base for all 

measurement channels and also contains an input 

for external start signals (8-pin Lemosa, connector 

compatible with speed board). 

◗ Monitoring of operating voltages 

◗ LED for input 

◗ Triggering by means of 32-bit DSP, 

firmware in RAM 

Rotational Speed Board (E-DR) 

These boards measure the periodic times of digital 

speed signals. One board is required per speed signal. 

Many boards are synchronised by the trigger 

board. 

◗ Single-channel, 8-pin Lemosa connector 

◗ 10 GHz (100 psec) counter/timer 

◗ 40-bit counter size 

◗ TTL-level input signals, voltage overload protection 

±40 V 

◗ Input frequency range from 0.01 Hz to 1 MHz 

◗ Input for rotational direction 

◗ 2 additional digital inputs 

◗ Provides sensor supply voltages 

◗ Start/Stop triggering on speed threshold 

or gradient 

◗ LEDs for inputs 

◗ Signal pre-processing by means of 32-bit DSP. 

Firmware in RAM 

8-channel Analogue Board (E-AN) 

These boards are designed for analogue sampling 

of the input signal. The trigger board ensures synchronisation 

of analogue and speed measurements. 

◗ Eight channels, SMB connectors 

◗ 50 kHz sampling rate per channel 

◗ 16-bit resolution 

◗ Input signals ±10 V, differential or current source 

◗ Voltage overload protection ±500 V 

◗ Input impedance differential 0.8 MOhm / 150 pF, 

Common mode 0.25 MOhm / 36pF 


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◗ 10 kHz hardware filter, switchable 

◗ Separate setting of sampling rate for each channel 

from 3Hz to 50kHz 

◗ Programmable amplification 1, 10, 100, 1000 

◗ AC/DC coupling 

◗ Start/Stop triggering on level or gradient 

◗ LED for input voltage overload 



2-channel Analogue Board (E-A2) 

These boards are designed for analogue sampling of 

the input signal. The trigger board ensures synchronisation 

of analogue and speed measurements. 

◗ Two channels, SMB connectors 

◗ 400 kHz sampling rate per channel 

◗ 16-bit resolution 

◗ Input signals ±10 V, differential or current source 

◗ Voltage overload protection ±500 V 

◗ Input impedance differential 107 MOhm / 150 pF, 

Common mode 0.25 MOhm / 36pF 

◗ 10 kHz hardware filter, switchable 

◗ Separate setting of sampling rate for each channel 

from 3Hz to 400kHz 

◗ Programmable amplification 1, 10, 100, 1000 

◗ AC/DC coupling 

◗ Start/Stop triggering on level gradient 

◗ LED for input voltage overload 



www.rotecmunich.de

DSE07-12.04 · Standard Speed Sensors · © 2004 rotec GmbH, Munich · Subject to change without prior notice 

Sensors 

Standard Rotational Speed Sensors 

The rotec sensors described here are designed for non-contact measurement of the rotational speed of a toothed 

wheel. Each sensor consists of two magnetoresistive elements and a permanent magnet enclosed in a stainless 

steel cylindrical housing with M10x1 outer thread. The sensors themselves are entirely passive. For operation they 

require an accompanying electronic unit which converts their analogue output to a TTL signal. The sensors exhibit 

minimal temperature dependence and their operation is not impaired by dirt or oil films. The output signal 

amplitude is independent of the rotational speed. A variety of lengths and designs is available. 

The sensors' stainless steel cylindrical housing has an M10x1 outer thread. The target wheel should have a gear 

module in the range 0.6 to 2.4mm, a pitch between 1.9 and 7.7mm and a thickness of at least 5mm. A sensing 

gap from sensor to wheel of up to 5mm is allowed for. The electronic unit operates for the tooth frequency range 

0.1Hz to 20 kHz, i.e. a tooth must be detected at least once every ten seconds. Differential magnetoresistive sensors 

need to be carefully positioned for both optimal adjustment of orientation w.r.t. the target wheel and setting 

of sensing distance. 

Measurement Principle Main Features: 

◗ M10x1 outer thread 

◗ Target wheel: ferromagnetic material 

Gear module: 0.6mm to 2.4mm 

Pitch: 1.9mm to 7.7mm 

◗ Sensing gap up to 5mm 

◗ Tooth frequency range: 0.1Hz to 20kHz 

◗ Sensor electronic unit: input 5mV to approx 80V, 

output TTL level (0/5V) 


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www.rotecmunich.de

DSE07-12.04 · Standard Speed Sensors · © 2004 rotec GmbH, Munich · Subject to change without prior notice 

Sensors 

Standard Rotational Speed Sensors 

Sensor Type A 

Sensor Type C 

Standard Sensor Electronic Unit 

Sensor Type B 


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Cable for Sensor Type B and C 

Inline Sensor Electronic Unit 

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DSE08-12.04 · Fourfold Sensors · © 2004 rotec GmbH, Munich · Subject to change without prior notice 

Sensors 

Fourfold Rotational Speed Sensors 

The rotec 'fourfold sensor' is used in order to increase the angular resolution of rotational-speed measurements. 

The sensors are used when the target wheels have a relatively small number of teeth, e.g. chain sprockets or 

gears within a gearbox. Each scanned tooth provides four data points. The sensor comprises 4 magnetoresistive 

elements with a permanent magnet enclosed in a stainless steel casing with M10x1 outer thread. The sensors require 

an accompanying electronic unit which converts their analogue output voltage to square wave TTL level. The 

sensors exhibit minimal temperature dependence and their operation is not impaired by dirt or oil films. 

Main Features: 

◗ Outer thread M10x1 


Gear module: 1mm to 2.5mm 

Pitch: 2mm to 6mm, ideally 2.5mm 

◗ Tooth frequency range: 1Hz to approx. 45kHz 

◗ Sensing gap up to approx. 1.5mm 

The sensor's stainless steel cylindrical housing has 

an M10x1 outer thread. The target wheel should have 

a gear module in the range 1 to 2.5, a pitch between 

2 and 6mm and a thickness of at least 5mm. A sensing 

gap from sensor to wheel of up to approx. 1.5mm 

is allowed for. The electronic unit operates for the 

tooth frequency range 1Hz to approx. 45 kHz. The 

magnetoresistor arrangement demands that the sen- 


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sors need to be carefully positioned for both optimal 

adjustment of orientation w.r.t. the target wheel and 

setting of sensing distance. An 'eightfold sensor' 

which provides eight pulses per tooth is also available. 

Measurement Principle 

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DSE09-12.04 · Speed Sensor with Rotational Direction · © 2004 rotec GmbH, Munich · Subject to change without prior notice 

Sensors 

Speed Sensor with Direction of Rotation 

The rotec 'fourfold sensor' may be used both to measure rotational speed and detect the direction of rotation. The 

sensor comprises four magnetoresistive elements and a permanent magnet encapsulated in a stainless steel 

housing with M10x1 outer thread. The magnetoresistors are arranged in pairs as two differential sensors [1 & 2 – 

see drawing below left]. The special electronic unit generates two phase-shifted speed-dependent signals. The 

first square-wave TTL pulse train constitutes the actual speed signal. The second pulse train is required for determining 

the direction of rotation. Both the first pulse train (speed signal) and a single bit (direction of rotation) 

are output to the RAS analyser. 

The sensor's stainless steel cylindrical housing has an M10x1 outer thread. The ferromagnetic target wheel should 

have a gear module in the range 0.6mm to approx. 2.4mm, a pitch between 2mm and 7mm and a thickness of at 

least 5mm. A sensing gap from sensor to wheel of up to approx. 2mm is admissable. 

The electronic unit operates for the tooth frequency range 0.1Hz to approx. 20 kHz. The magnetoresistor 

arrangement demands that the sensors need to be carefully positioned for both optimal adjustment of orientation 

w.r.t the target wheel and setting of sensing distance. 


◗ Outer thread M10x1 


Gear module: 0.6mm to 2.4mm 

Pitch: 2mm to 7mm 

◗ Tooth frequency range: 0.1Hz to approx. 20kHz 

◗ Sensing gap up to approx. 2mm 


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www.rotecmunich.de

DSE10-12.04 · Laser Tachometer · © 2004 rotec GmbH, Munich · Subject to change without prior notice 

Sensors 

Laser Tachometer 

The Laser Tachometer is a non-contact instrument which allows the user to measure the speed of rotation of a 

rotating component whose surface is fitted with an encoder consisting of alternate white and black sectors. Light 

which is reflected from the white sectors is received and digitised. Analogous to the scanning of a toothed wheel 

with a magnetic sensor, the electronic unit outputs a TTL pulse train whose frequency is proportional to the speed 

of rotation of the encoder. The use of visible light means that the user can easily aim the red-coloured beam spot 

onto the encoder target. 

Operating principle 

The complete tachometer system consists of an 

electronic unit and passive sensor head with integrated 

duplex fibre optic cable. The electronic unit 

contains a power-regulated emitter diode with wavelength 

670nm. The sensor head / duplex cable assembly 

is attached to the electronic unit with optically 

coupled connectors. The sensor head serves to 

both direct the light beam to the target, detect the reflected 

light and feed it back to the electronic unit's 

receiving diode. A control circuit compensates for 

varying sensing distances and degrees of surface 

reflection. 

As with all rotec sensors, power requirements are 

provided by the RAS system via 8-pin cable. Functionality 

is checked by an LED 'Lock' which illuminates 

when the encoder properly switches from reflecting 

to non-reflecting. 


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As with all forms of laser radiation the user should 

avoid direct eye exposure. 

Main features: 

◗ Class II laser device 

◗ Laser wavelength 670 ±10nm 

◗ Laser power 1mm 

◗ Distance to encoder surface using white diffuse 

paper: 20mm to 70mm 

◗ Power consumption on 12V line: 100mA 

◗ Operating temperature: 0 to 50°C (electronics), 

-40 to 120°C (optics) 

◗ Optical head outer thread: Imperial 1/2" 

Measurement setup 

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DSE11-12.04 · Rotary Encoder Adapter · © 2004 rotec GmbH, Munich · Subject to change without prior notice 

Sensors 

Rotary Encoder Adapter Unit 

Incremental rotary encoders provide information on the angular position of rotating shafts. The encoders generate 

two incremental signals, phase shifted to each other by 90° el., and a reference mark signal (once per revolution). 

These signals provide information which can be used in the determination of both the shaft's rotational 

speed and its direction of rotation. 

The DGADP signal conditioning unit described here is used for conditioning rotary encoder signals. Pulses can 

be measured in both the forward and reverse directions. The unit can be configured to measure various combinations 

of the distances between the edges of both pulse trains. An integrated divider circuit allows for reduction 

of the number of sampled pulses with dividing factors ranging from 1 to 215 . It is also possible to suppress a pulse 

from the first pulse train each time the index pulse (once per revolution) is detected. Setup is accomplished with 

DIP switches. Built-in green and red LEDs indicate direction of rotation and detection of the index pulse respectively. 


The encoders used should provide two 90° el. phaseshifted 

TTL square-wave pulse trains and an index 

pulse signal. The provision of two phase-shifted signals 

makes recognition of the direction of rotation 

possible. The encoders should also provide the inverted 

signals of the pulse trains since this aids in 

noise suppression. 

The electronics package is contained in an aluminium 

case. The power requirements are provided by 

the RAS analyser via an integrated 8-pin Lemosa 

socket. This connector also carries the output TTL 

signal. The encoder is connected to the 12-pin flange 

socket. For configuring the unit the top may be detached 

to allow access to the DIP switches. 

Setup 

Dividing factor: Dividing factors in the range 1 to 215 may be set: 

Interpolation / edge detection: Three different modes 

for detection of the edges of the TTL pulse trains 

may be set. (i) Only the positive edge of pulse train 

no. 1 is measured. (ii) Both the positive and negative 

edges of pulse train no. 1 are measured (interpola- 


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tion x2). (iii) The rising and falling edges of both 

pulse trains are measured (interpolation x4). 

Pulse suppression: A pulse is suppressed each time 

the index pulse is detected. 

Main features: 

◗ Input signal: Square-wave TTL 

(both pulse trains and index pulse) 

◗ Output signal: Square-wave TTL 

◗ Max. encoder input frequency: 

14 MHz for mode (i) - no interpolation 

8 MHz for mode (ii) - interpolation x2 

4.5 MHz for mode (iii) - interpolation x4 

◗ Output signal pulse width: 24ns 

◗ Operating temperature: 0 … +50°C 

www.rotecmunich.de

DSE12-12.04 · TTL Signal Adapter Unit · © 2004 rotec GmbH, Munich · Subject to change without prior notice 

Sensors 

TTL Signal Adapter Unit 

When the angular velocity (speed of rotation) of a rotating shaft is to be measured, sensors which detect at constant 

angular intervals around the shaft's circumference are widely used. The signal resulting from this type of 

measurement is a square-wave TTL pulse train whose frequency is proportional to the shaft's angular velocity. The 

periodic times (T) of the pulses (time interval from positive edge to positive edge) may then be measured with a 

high-speed counter/timer data acquisition board. The instantaneous angular velocity is then calculated by dividing 

the angle between the measuring points on the shaft circumference by the time intervals (T) from pulse to 

pulse. 

The TTLAD unit from rotec is used for detection of 

positive (rising) and or negative (falling) TTL-signal 

edges. Each time a positive and/or negative edge is 

detected the unit outputs a 10µs wide pulse 


◗ Input signal: TTL level pulse train 

◗ Output signal: TTL level, 10µs pulse width 

◗ Maximum input frequency: 49kHz 

◗ Delay time: maximum 40ns 

◗ Supply voltage: 5V 

Switch Settings 

There are three 'edge' switch settings: – 'pos', 'neg' 

and 'both'. The 'pos' (=positive) setting produces output 

pulses when positive edges are detected on the 


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input signal. The 'neg' (=negative) setting produces 

output pulses when negative edges are detected on 

the input signal. The 'both' setting produces output 

pulses when positive and negative edges are detected 

on the input signal. 

The TTL Adapter operates up to an input frequency 

of 49kHz (TTL input signals). The delay time between 

the input and output signal has a maximum 

value of 40ns. The supply voltage is 5V and the input 

is protected to ±80V. 

Input and Output Signals 

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DSE13-12.04 · 3-Button Unit · © 2004 rotec GmbH, Munich · Subject to change without prior notice 

Sensors 

3-Button-Operation Unit 

The 3-Button Unit may be connected with a cable to the serial port of an IEEE-1394 ('Firewire') RAS system. The 

RAS system may then, for example, be installed in the boot of the car undergoing test and the 3-Button Unit allows 

the driver to run the tests remotely. This applies only to the actual starting and stopping of measurements. 

All RAS-Software setups must be made beforehand via keyboard. The small 3-Button Unit is connected by an integrated 

cable to a RS232 port of the RAS system, RASnbk or RASf1 system. The computer is configured so that 

login automatically follows system operating voltage switch-on. Login then follows automatically, the RAS software 

starts and the appropriate measurement setup is activated. Automatic saving of the measurement data is also 

provided for. 

Setup 

This mode of operation is activated in the main RAS 

menu bar 'Extras / 3-Button Operation' together with 

selection of a serial port. Settings considered important 

for 3-Button Operation are highlighted in yellow. 

When this mode of operation is selected the 'Measure' 

function automatically starts when the RAS software 

is started. 3-Button Operation is stopped by 

pressing 'Close' in the measurement dialogue box 

with mouse or keyboard followed by de-selecting the 

'Activate 3-Button Operation for Measurement' check 

box. The rasmain.exe program may be added to the 

Windows Startup Menu ensuring automatic execution. 

Operation 

LEDs are integrated into the 3 buttons. A button's 

LED being ON indicates that the button may be 

pressed. Pressing a button otherwise has no effect 

on the program. Once the system has booted and 


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the RAS measurement program is primed, the green 

Start Button's LED is illuminated. In cases of error an 

appropriate message is shown on the screen 

(RASsys and RASnbk). A monitor may be connected 

to the VGA port of the RASf1 system to aid in finding 

the source of error. 

Buttons: 

Green Start - Start the measurement 

Orange Stop - Stop the measurement 

Red Shutdown - Close the program 

and shutdown the operating system. 

A double-click of the button within two 

seconds is required to protect against 

incorrect operation. 

LEDs: 

Orange Waiting - Awaiting trigger condition 

Green Measuring - Measurement is running 

Orange Saving - Data are being saved 

Red Error 

www.rotecmunich.de

DSE05-12.04 · RAS Software Overview · © 2004 rotec GmbH, Munich · Subject to change without prior notice 

RAS Software 

Overview 


may begin with a basic system comprising only a few channels and standard software and later expand to 

a system with many channels and a comprehensive range of data acquisition and analysis software. The modular 

architecture and versatile software make the equipment suitable for a wide range of testing and signal acquisition 

tasks. 

The RAS software provides the user with an easy-to-use, flexible and powerful tool for data acquisition and analysis. 

Signals may be analysed as a function of time, angle or rotational speed. FFT methods are used when converting 

from the time to the frequency and order domains. The common time base of all channels ensures reliable 

cross-channel evaluation of signals (e.g. transmission error or torque between two speed channels) and allows 

for correlation of analogue signals with speed data. 

The powerful RAS hardware allows for comprehensive time and spectral analyses with online display during the 

measurement. Immediately following the measurement, the time history data are stored on hard-disk. 

Setup of hardware and software for a test sequence 

is straightforward by means of easy-to-follow 

menus. 

Data analysis may be performed on the RAS system 

itself or on a desktop PC. Created graphic images 

can be exported to other applications via the Clipboard 

or Windows Metafiles. 


Tel: +49 (0) 89 323 651-0 · Fax: +49 (0) 89 323 651-56 

Animation software helps interpretation of measurement 

results by means of animated wireframe 

models. 

Simulation software generates mathematical models 

of the system undergoing test with frequency domain 

analysis. 

www.rotecmunich.de

DSE05-12.04 · RAS Software Overview · © 2004 rotec GmbH, Munich · Subject to change without prior notice 

RAS Software 

Overview 

Data Evaluation 

The RAS evaluation software is structured as follows: 

Firstly, a Synthesis may be applied to the raw data 

(e.g. inserting a missing tooth into the time history 

data). Then an Analysis may be performed on this intermediate 

result (e.g. calculation of the vibration 

angle versus time). Extras may then be applied to this 

new intermediate result (e.g. smoothing a curve). The 

end result is then incorporated into a Diagram whereby 

axes may be formatted. This is followed by generation 

of Pages, i.e. completed sheets for printer output. 

Evaluation sequences may be saved as macros 

for application at any time. 

Syntheses 

A Synthesis allows for pre-processing of raw data. 

The output data are then input to an Analysis. The 

following Syntheses are available for both speed 

and analogue data: 

◗ Removal of speed channel markings 

◗ Pitch error correction of toothed wheels 

◗ Special speed sensors 

◗ Filtering 

◗ Level rating 

◗ Vector operations 

◗ Strain guage rosettes 

◗ Analogue sensor characteristic curves 

Analyses 

An Analysis is a calculation performed on speed, 

analogue or CAN data. The following ordinates are 

available for all Analysis types: 

for speed channels 

◗ Rotational speed in [rpm], speed fluctuation in 

[rpm] 

◗ Angular velocity in [deg/s], [rad/s] 

◗ Vibration angle in [deg], [rad] 

◗ Angular acceleration in [deg/s2 ], [rad/s2 ] 

for analogue channels 

◗ Analogue value 

◗ 1st and 2nd derivative, 1st and 2nd integral 


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for 2-channel speed evaluations 

◗ Angle of twist / torque, transmission error in 

[µm], [µrad], [deg], [arc sec] 

◗ Speed difference in [rpm] 

◗ Slip [1] or in [%] 

Time history 

Single and difference channel calculations versus 

time, angle or revolutions. 

Angle 

Single and difference channel calculations versus 

angle. Waterfall or 2-dim cuts. Sub-division of measurement 

into cycles of finite size (user-defined). 

Pitch error correction 

Determination of tooth-to-tooth spacing error for subsequent 

correction. 

Valvetrain 

Special analyses for valvetrain measurements – lift, 

closing velocity, bounce, etc. 

Gear Testing 

Single flank testing of gearsets incl. differentials and 

multi-staged gears. 

Spectral domain 

Order and frequency analysis. Amplitudes, phases, 

vector plots and inverse transformations. 

Peak, peak to peak, rms, linear, logarithmic. 

2-dim and 3-dim plots, contour and Campbell plots 

versus time or speed. Several calculation methods for 

summation (overall level). 

Octave filter 

2-dim or Waterfall plot of results of octave-filtered 

data. 

Extras 

These tools are designed for post-processing of the 

results of an Analysis. Examples are smoothing of 

curves, statistical calculations and ASCII conversion. 

◗ Scaling 

◗ Statistics for 2-dim and Waterfall plots 

◗ Spectrum with up to 16k lines 

◗ Filter designer 

◗ Smoothing 

◗ Correlation 

◗ General formula, pocket calculator function for 

curves 

◗ Limits 

◗ Data conversion 

www.rotecmunich.de

DS06-12.04 · Einflankenwälzprüfung · © 2004 rotec GmbH, München 

Software 

Einflankenwälzprüfung 

Die Qualität eines Getriebes wird immer stärker durch seine Geräuschemissionen bestimmt. Unter-suchungsmethoden 

wie Geräusch- und Einflankenwälzprüfung erlangen somit eine wachsende Bedeutung. Die konventionelle 

Einflankenwälzprüfung, die definitionsgemäß bei niedrigen Drehzahlen (ca. 20 Upm) und nahezu lastfrei durchgeführt 

wird, eignet sich sehr gut zur Beurteilung der Fertigungsqualität von Verzahnungen. Eine Beurteilung des 

im realen Betrieb zu erwartenden Lauf- und Geräuschverhaltens erfordert jedoch eine Wälzprüfung unter Last 

und Betriebsdrehzahl. 


Idealerweise sollte ein Zahnradpaar eine Drehbewegung 

gleichförmig übertragen. Die Wälzabweichung 

ist die Differenz zwischen der gemessenen Position 

eines Zahnrades und der Position, die dieses einnehmen 

müßte, falls die Räder des Zahnradpaares 

perfekt zueinander passen würden. 

Wälzabweichungsmessung 

Meist besteht der Meßaufbau aus der Adaption 

zweier hochauflösender Winkelschrittgeber an den 

Achsen der zu untersuchenden Zahnräder. Das rotec 

System mißt auf An- und Abtriebsseite die Durchgangszeiten 

der Strichsegmente. Man erhält so die 

Winkelpositionen von Rad und Ritzel, woraus die 

Wälzabweichung berechnet wird. Die Auflösung bei 

dieser Meßmethode ist aufgrund der hohen Taktfrequenz 

der Meßkanäle sehr hoch. Desweiteren ist 

durch die Auswertung jedes Striches eine exakte 

Nachbildung der einzelne Zahneingriffe möglich. 

Die Kurve des Gesamtfehlers (Einflanken-Wälzabweichung) 

resultiert aus der Berechnung der Winkelabweichung 

zwischen beiden Winkelschrittgebern. Der 

angezeigte Verlauf zeigt dann die Exzentrizät der 

beiden Wellen sowie den Zahneingriff. Man erkennt 

ein kurzperiodisches Muster, welches sich einmal pro 

Zahn wiederholt, und eine langwellige Komponente, 

die sich einmal pro Umdrehung wiederholt. Der 

kurzwellige Anteil (einmal pro Zahn oder öfter) resultiert 

aus der Verzahnungsgeometrie (Balligkeit, usw.) 

sowie aus Unregelmäßigkeiten der Zahnoberflächen. 

Der langwellige Anteil entsteht durch Rundlauffehler 

beider Räder. Zusätzlich können Anteile 

vorhanden sein, die z.B. durch Befestigungsbohrungen 

verursacht werden und keinen Bezug zum Zahneingriff 

haben. 

rotec GmbH · Joseph-Dollinger-Bogen 18 · D-80807 München 

Tel: +49 (0) 89 323 651-0 · Fax: +49 (0) 89 323 651-56 

Um ein komplettes Bild des Zahneingriffsverhaltens 

zu erhalten, sollte mindestens eine komplette Überrollung 

vermessen werden. Das rotec-Programm 

kann dann durch geeignete Mittelungsverfahren 

zwischen Tellerrad und Ritzel separieren. Der langwellige 

Anteil entsteht durch Tiefpaßfilterung des Signals 

mit einer Eckordnung bei 1/3 des Zahneingriffs. 

Wird diese Kurve vom Gesamtsignal subtrahiert, 

bleibt der kurzwellige Anteil. 

Andere Meßgrößen 

Neben der Wälzabweichung ermöglicht das rotec- 

Meßsystem die Aufnahme und Berechnung von 

weiteren Größen wie die Drehbeschleunigungen von 

Rad und Ritzel, der Körperschall an den Lagerstellen, 

sowie der abgestrahlte Luftschall. Das Meßsystem 

gewährleistet die zeitgleiche Erfassung aller 

Meßgrößen. Da eine Ordnungsanalyse aller Signale 

möglich ist, können beispielsweise Zusammenhänge 

zwischen der Wälzabweichung und der Geräuschentwicklung 

einer Verzahnung aufgezeigt werden. 

DIN Werte 

F ' i Gesamtfehler (Einflanken-Wälzabweichung ) 

f' l langwelliger Anteil 

f' k kurzwelliger Anteil 

f' max Maximalwert des Zahn-zu-Zahn-Fehlers 

(Einflanken-Wälzsprung) 

f' mit mittlerer Zahn-zu-Zahn-Fehler 

www.rotecmunich.de

DS06-12.04 · Einflankenwälzprüfung · © 2004 rotec GmbH, München 

Software 


Beispielauswertungen für ein Kegelradpaar 

Ritzel/Tellerrad: 13/40 Zähne. Antriebsdrehzahl: 300 Upm. 

Drehrichtung: Zug. Winkelschrittgeber: Strichzahl 18000. 

Lastmoment: 20Nm. 

Bedienerfreundliche Softwareoberfläche 

Die Wälzabweichungskurven zeigen die Abweichung 

der Winkelposition des Tellerrades zum Sollwinkel 

rotec GmbH · Joseph-Dollinger-Bogen 18 · D-80807 München 

Tel: +49 (0) 89 323 651-0 · Fax: +49 (0) 89 323 651-56 

Das Spektrum der Wälzabweichung enthält u.a. 

Ordnungen des Zahneingriffs 

www.rotecmunich.de

Measurement and Analysis Systems Complete RAS Systems for ...

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