Program Continuation:

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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