Consilium ST450EC - Functions

15
ST450EC
v1.11
3.1 Functions
Output signal
Each ST450EC sensing head is supplied with a transmitter PCB with a 4-20mA interface. This
transmitter PCB converts the sensor signal to an analogue 4-20mA signal. The sensing head has
a number of predefined output levels.
Output signal
Status
0 mA
Sensing head is not (correctly) connected
Power supply missing
< 2,4 mA
System error / Sensor error
4-20mA
Normal operation
> 20 mA
Out of range / overload
For description of the relationship between the gas concentration and corresponding output signal,
see Appendix C of this manual.
MODBUS
The ST450EC transmitter PCB features a RS-485 communication interface, which enables
communication capabilities for industrial installations to communicate with the ST450EC
sensing head. Since RS-485 uses a half- or full-duplex communication system, the MODBUS
protocol has been selected. Please contact Consilium for more information on the protocol.
With the use of RS-485 serial communication, up to 31 sensing heads are able to communicate
through one connection cable without the use of additional amplification equipment. The
address of each sensing head is set with the DIP-switch array S1. Each sensing head has a
unique address.