PLC sign-of-life monitoring
The PLC must give a sign of life within a defined period of time (machine data 10100 PLC_CYCLIC_TIMEOUT). If this does not occur, the alarm is triggered.
The sign of life is a counter reading on the internal NC/PLC interface which the PLC causes to count up with the 10 ms time alarm. The NCK also tests cyclically whether the counter reading has changed.
- NC not ready.
- Local alarm reaction.
- Channel not ready.
- NC Start disable in this channel.
- Interface signals are set.
- Alarm display.
- NC Stop on alarm.
Please inform the authorized personnel/service department. Check monitoring time frame in NCK-MD 10100 PLC_CYCLIC_TIMEOUT (reference value: 100ms).
Establish the cause of the error in the PLC and eliminate it (analysis of the ISTACK. If monitoring has responded with a loop in the user program rather than with a PLC Stop, there is no ISTACK entry).
Switch control OFF - ON.
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