Troubleshooting Examples - Siemens PM330 Hardware Installation Manual

Appendix
A.3 Application examples for functional safety (STO / SS1-t)
A.3.4

Troubleshooting examples

Description of the situation
STO is deactivated at the safety system sensor.
CU signals in the IOP, parameter r0002 = [44] "Switching on inhibited – connect 24 V to
terminal STO (hardware)" -> STO is active in at least one channel of the PM330.
Only troubleshooting examples are described here; for a specific problem, refer to the
operating instructions of the 3SK1 involved, e.g. the significance of LED 1.
3SK1111... safety relay used
Scenario 1:
● LED 1 DEVICE lights up green
-> power supply and power up are OK
● LED 2 OUT is OFF
-> the safety circuit is not enabled
Possible causes:
● Feedback circuit is not closed
– The feedback circuit wiring is interrupted
– The incorrect cycle output is being used
– PM330 fault
● Fault in the 3SK1 feedback circuit
– At least 1 switch-off signal path of the PM330 is still active (at least 1 of the two STO
● PM330 fault
– PM330 power supply missing -> establish the power supply
– One or two switch-off signal paths of the PM330 is/are defective
– One or two feedback signal paths of the PM330 is/are defective
● Fault in the 3SK1 sensor circuit
– 1 channel of the 3SK1 sensor circuit was not opened when activating STO (low signal)
● Start enable or acknowledgment missing
– Start enable missing or actuated too long (switch 1 set to MONITORED)
130
inputs has a high signal), e.g. cross-circuit fault in the 3SK1 enable circuit
-> restart inhibit
-> repair/replace the sensor
-> or the wiring must be checked
Hardware Installation Manual, 12/2018, A5E32844552B AF
Power Module PM330