22101

Navigate to Diagnostics > Machine Data > Spindle Parameters (MD 20100-20150 range) in NCK menu. Locate MD20130 (max encoder speed [rpm]) or MD20131 (max encoder speed [Hz]).

Cross-reference encoder datasheet maximum frequency rating. Verify MD20130/MD20131 is set to at least 90% of encoder specification to account for signal quality margin.

Setting value >95% of encoder spec risks intermittent synchronization loss.

Compare alarm block number (%3) and commanded speed against actual spindle max RPM. If commanded speed is within spindle capability, increase MD20130/MD20131 and retrigger G33/G95/G96/G97 block.

Activate Machine Data in HMI, save changes, perform warm restart (soft reset) to load updated encoder limits into NCK.

In Diagnostics > Actual Values > Spindle menu, monitor encoder frequency (Hz) and encoder position deviation (increments) during alarm condition. Verify encoder signal is present and stable at 50% of commanded setpoint speed.

Disconnect spindle drive while checking encoder connector (ISO 13849 safety lockout required).

Inspect spindle encoder cable (typically Hirschfeld or similar industrial connector) for corrosion, loose pins, or shielding damage. Check cable routing for kinks near motor heat sources.

Perform encoder signal test via Diagnostics > Test Functions > Encoder Test. Verify pulse train frequency increases linearly with spindle speed ramp-up; observe for signal dropout or jitter above 80% of MD20130 limit.

If signal unstable, reseat encoder connector and retest. If failure persists, replace encoder and recalibrate MD20135 (encoder lines/rev) and MD20136 (encoder direction).

Navigate to Drive Parameters (via STARTER software or HMI) and verify spindle drive switching frequency (PWM) is set ≥8 kHz. Encoder signal frequency must be <10% of drive PWM frequency to avoid aliasing.

Check MD20140 (encoder filter time constant [ms]) and MD20141 (encoder deviation tolerance [increments]). Increase MD20140 by 2-5ms if signal jitter detected; verify MD20141 allows ±5-10 increment tolerance.

Over-filtering (MD20140 >50ms) degrades G33 thread pitch accuracy.

In Diagnostics > Drive Status, confirm spindle motor current is stable (no excessive ripple) and temperature <70°C at alarm-triggering speed. High current ripple indicates inadequate drive tuning.

If ripple evident, reduce MD20100 (spindle setpoint accel limit) by 10-20% to stabilize speed feedback loop, then retest G33/G95 command. Contact drive OEM if tuning insufficient.