20125

Access NCK machine data via HMI menu: Maintenance > Machine Data > search 'MD 32730'. Note the current CEC_MAX_VELO value (typically in mm/min or equivalent units).

Review the NC program for compensation changes via G-code: check for rapid DL (tool length offset) or DW (wear offset) activations or G65/G66 macro calls that modify offsets dynamically.

Increase MD 32730 CEC_MAX_VELO incrementally (e.g., by 10-20%) to match or exceed the required compensation change rate. Typical industrial values range 50-500 mm/min depending on axis type.

Verify machine mechanics can tolerate higher compensation velocities without causing vibration or thermal issues before deployment.

Test the modified program and monitor for alarm 20125 recurrence. If alarm clears, verify contour accuracy with CMM or in-process gauging to confirm no path deviations occurred.

Check PLC program for custom compensation logic: navigate to NCK PLC screen and examine the tool offset/wear compensation blocks (typically in OB100, OB35, or dedicated compensation FB). Look for SPOS (set position), tool offset write operations, or analog input polling loops.

Verify if tool wear compensation or gauging mode is active via SD (setting data): review SD 43400+ (tool offset/wear parameters) and confirm compensation enablement flags and update cycle times.

If using automatic gauging (APC/CPC), reduce the compensation correction magnitude per cycle or extend the cycle interval to lower the rate of change. Alternatively, increase MD 32730 CEC_MAX_VELO or use synchronous compensation (slower ramp-rate in the offset application).

Test modified compensation logic offline in SIM mode first to avoid production scrap.

Monitor alarm log (Diagnostics > Alarms > History) and correlate alarm 20125 timestamps with tool offset write timestamps or cycle events to confirm the trigger pattern.

Run servo diagnostics: Maintenance > Diagnostics > Axis diagnosis. Check position error (POSERR), velocity error (VELERR), and encoder signal quality (CNT_ERR, resolver frequency) for the affected axis.

Inspect feedback transducer and cabling: verify encoder/resolver connector integrity, test continuity, and oscilloscope the encoder signal for noise spikes or dropout events during the alarm occurrence window.

Review axis servo tuning: check MD 36400+ (P-gain, I-gain, D-gain, feedforward) for the affected axis. If tuning is aggressive or unstable, reduce P/D gains or increase I time constant to smooth compensation demand.

If hardware appears sound, increase MD 32730 CEC_MAX_VELO as a temporary workaround; log the issue for deep-dive servo stability analysis with Siemens field support if alarms persist.