Signaling Threshold
Short Description
The product signals a value falling below a non-adjustable, asymmetric isolation resistance between +24 V or 0 V of the supply voltage and ground by means of a potential-free con-tact (“Iso OK”) and status LED. The “Iso OK” contact can be evaluated via a PLC.
This status is maintained until the next measurement interval.
Operation with Grounded Control Circuit (Functional Potential Equalization)
Operation with Ungrounded Control Circuit
“Iso OK” Contact
The product signals a value falling below a non-adjustable, asymmetric isolation resistance between +24 V or 0 V of the supply voltage and ground by means of a potential-free con-tact (“Iso OK”) and status LED. The “Iso OK” contact can be evaluated via a PLC.
This status is maintained until the next measurement interval.
Operation with Grounded Control Circuit (Functional Potential Equalization)
- The module establishes an internal connection between the 0 V (X2.2) and ground (X2.1) connections via a semiconductor switch.
- At 10 s intervals, the connection between 0 V and ground is interrupted for 0.5 s, and the isolation resistance between +24 V (X1.3) or 0 V (X2.2) of the supply voltage and earth (X2.1) is determined.
- The grounding connection on the module does not meet the requirements of a protective earth terminal (PE). It serves as a functional ground. The measurement method does not involve the module establishing any permanent connection bet-ween 0 V and ground.
Operation with Ungrounded Control Circuit
- In this operating mode, the semiconductor switch to establish a connection between 0 V (X2.2) and ground (X2.1) is deactivated. At 1 s intervals, the isolation resistance offset is determined for 0.5 s.
- The module does not meet the requirements of an isolation monitoring device per EN 61557-8.
“Iso OK” Contact
- The potential-free contact serves the purpose of supporting evaluation (e.g., via a PLC) of looming isolation faults.
- This contact must not be used to switch safety-related products that could cause the circuit to switch off.