1735 Technical Manual - Novatech Controls

7.2.25 Reference Air Pump Options
Normally the reference air is supplied from the transmitter using the internal pump. The pump will be a
model MP-24 or a model CM-15. The default options are to use an Internal MP-24 pump at 2.00v.
Function
Options
52 Reference Air Pump External or Internal
53 Internal Pump Voltage MP-24 select 2.00v, CM-15 select 3.5v
54 Reference Air RH% If external is selected, set the RH level. (5% if instrument air is used)
7.2.26 Communications Port Options
The 1735 transmitter has a serial communications port available at terminals 18 to 22. The default protocol
is for RS-232 running at 19,200 baud rate with 8 bits, Even parity and 1 stop bit.
Function
Options
55 Serial Interface RS-232 or RS-485 (Use RS-485 for MODBUS)
56 Serial Baud Rate 9600, 19200, 38400, 57600 (RS-232 up to 19200 only)
57 Serial Parity Even, Odd or No Parity
58 MODBUS Address
Set the MODBUS address for this device between 1 and 246.
0 is to disable the MODBUS
7.2.27 Alarm Log Clearing
Every alarm that is instigated internally in the transmitter or as a process level is recorded in the alarm log
with the activation time, accepted time and the cleared time. The last 4000 events will be recorded and then
the oldest alarms will be dropped off as new ones occur. If you would like to delete the log recording select
CLEAR in SETUP step 64 by using the OPTION keys and press the ENTER key. The message “Alarm Log
Cleared” will be displayed.
7.2.28 External Oxygen Input Delay
If the chosen operating mode is “Directly Heated, External Dry Oxygen”, then the dry oxygen signal will need
to be fed into the BFT terminals 24 & 25 as a 4-20mA signal scaled 0-25% oxygen. If there is a gas
transport lag between the oxygen reading from the in-situ oxygen probe and the sample of the oven / dryer
gas taken through the sample gas dryer, then a compensating delay can be entered into function #6 in the
commissioning menu. The time can be between “No Delay” and 600 seconds (10 minutes).
April 2012
48 1735 Water Vapour Transmitter