Sinumerik Alarm 2000 PLC sign-of-life monitoring

Sinumerik Alarm 2000 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.

– Local alarm reaction.
– NC not ready.
– 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).1-20 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).

Program Continuation:
Switch control OFF – ON.


  1. Siemens Diagnostics Guide by Siemens
Sinumerik Alarm 2000 PLC sign-of-life monitoring