Control Unit Models 9010 LCD and 9020 LCD
16
Configuration
MSA
GB
5.5 Predisposed for input signal
The Control Unit 9010/20 LCD general purpose version, depending on the sensor or transmitter
to be connected, can be configured to receive signals in mV or in mA, check table for the hardware
predisposition of the Control Unit.
The software predisposition is made in Access Code 52, step 3:
- setting datum 1 selects an input signal in mV [ex. catalytic sensors].
- setting datum 2 accepts a 4/20 mA input signal for two-wire transmitters
[ex. electrochemical sensors]
- setting datum 3 accepts a 4/20 input signal for three-wire transmitters
[ex. infrared detectors, field transmitters].
The Control Units configured by setting data 2, 3 are automatically calibrated between
4 and 20 mA and do not need further checks.
Control Unit 9010/20 LCD version 4/20 mA article no. 10093585 / 10093584 is predisposed to ac-
cept in inputs only signals 4/20 mA from 2- or 3-wire transmitters, the calibration is automatically
made on the 4/20 mA input signal.
5.6 Output Signals
Analogue signals
The selection of the analogue type signal, relative to the condition of regular operation, is per-
formed with Access Code 4, step 19.
0*20 mA, 4*20 mA, 20*0 mA and 20*4 mA signals are available.
The indication of the analogue type signal in the event of a failure is done with Access Code 4,
step 20.
The following signals are available: 0 mA, 2 mA, 4 mA, 20 mA or h [corresponding to the value of
the signal frozen at the moment of the failure].
It is possible to make corrections of the 4-20 mA analogue signal via steps 23 and 24 of access
code 4; in this way, the alignment with other purchased systems will be possible.
The behaviour of the analogue signal in correspondence to the various access codes is shown for
each of these.
RS485 signal
The serial output RS485, of the interactive type, can be utilised for the connection with Supervision
Systems, PLC, DCS, etc.
The data transmitted on a RS485 HALF DUPLEX type serial bus with MODBUS protocol, con-
nected to a Supervision System are as follows:
configuration of the current Control Unit with the possibility of modification, concentration values
of the monitored substance, alarm and failure conditions, execution of the horn cut-out and reset
of the alarm state.
Upon request it is possible to furnish output RS485 in a redundant form.
The MSA Technical Support Department is at your service for any technical questions.
Remember that these configurations are normally made in the factory in accordance
with the specifications of the customer.
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