100933

Perform NCK reset using "Reset NCK" from HMI Service screen or power cycle the control completely. Document any active NC programs and machine state before reset.

Ensure machine is in safe position and all axes are stationary before NCK reset

Check alarm log (Service -> Alarm -> Archive) for preceding alarms that may indicate which task or process triggered the semaphore lock. Look for channel alarms, axis errors, or PLC communication faults within 5 seconds before alarm 100933.

Review any recent part program changes, especially synchronized actions (SYNR, SYNA), multi-channel operations, or interrupt routines (ASUP) that may create race conditions. Test machine with simple MDI commands first.

If alarm recurs, create NCK diagnostic dump via Service -> Diagnosis -> NCK -> Create Diagnostic File and contact Siemens support with alarm timestamp correlation.

Access PLC program and check for excessive NCK interface variable access in cyclic OB1 or fast interrupt OBs. Review DB variables mapped to $A_IN/$A_OUT system variables for optimization.

Monitor PLC cycle time via PLC diagnostics screen. Verify OB1 cycle time is under 80% maximum. Check for OB85 (cycle time exceeded) errors in PLC diagnostics buffer.

Reduce PLC-NCK communication frequency by implementing handshake protocols instead of continuous polling. Use edge-triggered reads rather than level-triggered continuous access.

Check NCK load via Service -> Diagnosis -> NCK -> Performance. If IPO cycle load consistently exceeds 70%, reduce interpolation frequency or redistribute calculation-intensive functions.

Verify software version consistency: Access Service -> Version -> Software Version. Check that NCK kernel, HMI software, and PLC firmware are from same PowerLine/ServicePack release. Document all versions.

Check NCK file system integrity via Service -> Startup -> File System Check. Enable 'Check file system' option and perform warm restart to verify no file corruption exists.

File system check may take 10-15 minutes; machine will be unavailable during this process

If recent software update was performed, verify all required option licenses are valid via Service -> Diagnosis -> NCK -> License Management. Missing or expired licenses can cause task conflicts.

Consider restoring NCK to last known good configuration using archive backup. If alarm started after specific change, perform selective restore of system data archives from before the issue began.

Ensure valid backup exists before attempting restore operations