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Power down and inspect table

Turn off machine power and manually rotate the table to check for binding, chips, or workpiece interference.

Ensure machine is fully powered down and locked out before manual inspection

Clear obstructions

Remove any chips, coolant buildup, or workpiece clamps that may be interfering with table rotation.

Check underneath the table where chips commonly accumulate

Check table mounting

Verify rotary table is properly secured to machine table and all mounting bolts are tight.

Loose mounting can cause binding during rotation

Test rotation

Power up machine and test rotary table movement in JOG mode at slow feed rate to verify smooth operation.

Check servo drive status

Navigate to DIAGNOSTICS > SERVO and check A-axis drive status for fault codes or overload indicators.

Look for red fault indicators on the servo drive display

Verify motor connections

Inspect A-axis servo motor power and feedback cable connections for looseness or damage.

Check connections only with power off to avoid electrical shock

Reset servo drive

Press RESET button on control and attempt to clear the alarm, then test A-axis movement.

If alarm immediately returns, servo drive likely has internal fault

Check servo parameters

Verify A-axis servo parameters 720-729 are set correctly for your rotary table model and load.

Check encoder connections

Inspect A-axis encoder cable connections at both motor and control cabinet for looseness or corrosion.

Encoder cables are typically shielded and more sensitive than power cables

Verify encoder signals

Navigate to DIAGNOSTICS > ENCODER and observe A-axis encoder counts during manual rotation.

Counts should increment smoothly without jumping or sticking

Test encoder integrity

Use MDI mode to command small A-axis moves and verify position feedback matches commanded position.

Start with very small moves (1-2 degrees) to avoid damage if feedback is incorrect

Check parameter 28 (A-axis)

Verify parameter 28 A-axis encoder resolution matches your rotary table specifications.

Check following error limit

Navigate to SETTING > PARAMETERS and check parameter 25 (A-axis following error limit) - typical value is 0.005-0.020 inches equivalent.

Lower values provide tighter control but may cause nuisance alarms

Monitor actual following error

Use DIAGNOSTICS > POSITION to observe real-time A-axis following error during moves.

Following error should stay well below parameter 25 limit during normal moves

Adjust servo gains

If following error is excessive, carefully increase A-axis velocity gain (parameter 720) in small increments.

Improper servo tuning can cause instability or motor damage

Reduce feed rates

Test with slower A-axis feed rates to determine if following error is speed-dependent.

Check power supply voltages

Verify DC bus voltage and servo power supply voltages are within specification using control diagnostics.

Low voltage can cause servo performance issues before triggering voltage alarms

Inspect electrical connections

Check all A-axis power and signal connections for tightness, corrosion, or heat damage.

Use lockout/tagout procedures when inspecting electrical connections

Test with other axes disabled

Isolate A-axis operation by testing it independently to rule out power sharing issues.

This helps identify if the problem is A-axis specific or system-wide