330-0078

Check drive communication status

Navigate to MOD function → Machine Parameters → Check MP1020 (axis assignment) and verify drive is properly configured for affected axis.

Use LSV2 protocol diagnostics to verify real-time communication status

Verify cable connections

Inspect EnDat/encoder cables between TNC and servo drive for loose connections, damage, or EMI interference.

Power down system before checking cable connections

Test drive response

In Manual mode, attempt small movements on affected axis while monitoring PLC status and drive LED indicators.

Check MP1041 (monitoring window) settings if movements are erratic

Check encoder parameters

Verify MP1003 (encoder type), MP1006 (encoder pulses), and MP1013 (reference marks) match actual encoder specifications.

Use encoder test function in Service menu to verify signal quality

Inspect encoder signals

Navigate to Position Display → Encoder and check for stable position values and proper incremental counting during manual movement.

Erratic position display indicates encoder hardware failure

Verify encoder power supply

Check +5V or +12V encoder supply voltage at drive terminals and ensure proper grounding of encoder shield.

Measure encoder supply under load - voltage drop indicates power supply issues

Check drive status LEDs

Examine servo drive front panel LEDs for error codes and compare with drive manufacturer documentation.

Red LED typically indicates drive fault requiring immediate attention

Verify drive power supply

Measure DC bus voltage and ensure proper 24V control voltage to drive, check for voltage fluctuations during operation.

Use oscilloscope to check for AC ripple on DC bus - excessive ripple indicates power supply issues

Test drive isolation

Disconnect motor cables and test drive enable/disable functions through TNC to isolate drive electronics from motor issues.

Drive should accept enable commands even without motor connected

Review monitoring parameters

Check MP1040 (position monitoring), MP1041 (monitoring window), and MP1042 (monitoring time) for appropriate values matching machine characteristics.

Monitoring window should be 2-3x typical following error during normal operation

Adjust following error limits

Navigate to Machine Parameters → Axes → Following Error and verify MP1044 settings allow sufficient tolerance for machine dynamics.

Overly tight monitoring can cause nuisance alarms during rapid movements

Test parameter changes

Perform test movements at various feed rates to verify monitoring parameters allow normal operation without false alarms.

Use Position Display to monitor actual following error during test movements