Consilium ST450EC - APPENDICES; Connection Data; Gas Concentration vs. Output Signal

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ST450EC
v1.11
10. APPENDICES
A. Connection data
The following diagram shows a view of the main PCB of the ST450EC sensing head. The sensor
is connected to connection block CN1. The connection cable (power supply and measurement
signal) and the RS485 communication cable are connected to the connection block CON1.
Connector CON 1
Output
SIG
+24 Vdc
0 Vdc
Data - (B/Rx)
Data + (A/Tx)
CON 1
0 - 25mA
Vin
GND
B -
A +
B. Relationship gas concentration vs. output signal
Output signal
Status
0 mA
Sensing head is not connected, Power supply missing
< 2 mA
System error / Sensor error
4-20mA
Normal operation
> 22 mA
Out of range / overload
Output signal
Relation full
scale output
O
2
concentration
in volume %
H
2
S concentration
in ppm
CO concentration
in ppm
4 mA
0 %
0.0
0
0
5.6 mA
10 %
2.5
10
50
8 mA
25 %
6.25
25
125
12 mA
50 %
12.5
50
250
16 mA
75 %
18.75
75
375
17.4 mA
83 %
20.9
-
-
20 mA
100 %
25.0
100
500