Monitoring the sensor connection requires a maximum cumulative resistance value Rs for the sensors connected to the module's inputs. This maximum value (Rs) is compatible with the normal operation of the TSX AEY 414 module.
The sensor connection fault may indicate a short-circuit or an open circuit, depending of the type of sensor in use. However, the error report is quite general and does not differentiate between a short-circuit and an open circuit.
Table of Resistance Values:
|
Sensor
|
Thermowells Pt1000/Ni1000
|
Thermowell Pt100
|
Thermocouples -15/60 mV, B, E, J, K, L, N, R, S, T and U
|
|
Max. Rs
|
-
|
0
|
100 Ohms
|
|
Open circuit
|
> 3850 Ohms
|
> 400 Ohms
|
100000 Ohms
|
|
Short-circuit
|
150 Ohms
|
15 Ohms
|
undetectable
|
NOTE: The module ensures consistency between the wiring terminal fault and the sensor connection fault. The sensor connection fault is not detected in range 0-5 V / 0-20 mA (this service is not offered to the user, and the wiring test is not performed).
In the 1-5 V / 4-20 mA range, the wiring test is meaningful only if the 250W shunt is connected. If the shunt is not connected, the wiring test may not be able to detect a fault, even is cables were cut.
In the case of thermowells, the sensor connection fault due to a line compensation anomaly may appear or disappear with a maximum delay of 12 s, from the occurrence of said anomaly.
