231-8820

Check encoder reference mark detection

Navigate to MOD function 'Encoder test' and monitor the reference mark signal (C track) during manual axis movement through the reference position.

The reference mark should show a clean pulse transition - any noise or missing pulse indicates encoder issues.

Inspect encoder scale/disk

Physically examine the encoder scale or rotary disk for contamination, scratches, or damage at the reference mark location.

Power down the machine before physical inspection to prevent electrical hazards.

Clean encoder components

Use lint-free cloth and appropriate cleaning solution to clean the encoder reading head and scale/disk, ensuring no residue remains on the reference track.

For linear encoders, check that the scanning head maintains proper gap distance (typically 0.1-0.5mm).

Verify encoder cable integrity

Check encoder cable connections at both ends and test cable continuity, particularly the reference mark signal lines.

Use proper ESD precautions when handling encoder electronics.

Verify motor parameters in MP7200 series

Access machine parameters and check MP7210 (motor type), MP7211 (pole pair number), and MP7212 (motor constant) match the actual motor specifications.

Motor parameters must exactly match manufacturer specifications - even small deviations can prevent field angle detection.

Check encoder resolution settings

Verify MP7220 (encoder resolution) and MP7221 (encoder type) are correctly configured for the installed encoder model.

Incorrect encoder resolution can cause position feedback errors and prevent proper commutation.

Validate commutation parameters

Review MP7230 (commutation method) and MP7231 (field angle offset) settings in the drive parameter menu.

Set MP7230 to automatic commutation (value 1) to allow the TNC to determine field angle automatically.

Perform parameter reset and reload

Backup current parameters, reset motor parameters to default, then reload with correct motor-specific values from manufacturer documentation.

Check drive enable status

Verify the servo drive is properly enabled and monitor MP7100 (drive status) for any fault conditions that prevent commutation.

Drive must be fully enabled and fault-free before field angle detection can occur.

Verify motor current settings

Check MP7240 (rated motor current) and MP7241 (maximum motor current) are set appropriately for the motor specifications.

Insufficient current settings can prevent the drive from generating enough torque for field angle detection.

Monitor commutation sequence

Use the TNC diagnostic screen to observe the automatic commutation process during axis reference run, watching for current spikes or irregular behavior.

Successful commutation shows smooth current transitions and consistent encoder feedback during the learning cycle.

Perform manual commutation reset

Access the drive setup menu and initiate a manual commutation reset, then execute a new reference run to re-learn the field angle.

Check mechanical freedom of movement

Manually move the axis through its full range to identify any binding, excessive friction, or mechanical obstructions.

Ensure machine power is off and axis brakes are released before manual movement.

Inspect coupling and transmission

Examine motor coupling, ballscrew, and transmission components for wear, damage, or misalignment that could cause excessive load.

Listen for unusual noises during movement - grinding or binding sounds indicate mechanical problems.

Verify lubrication system

Check that all axis lubrication systems are functioning and that ways, ballscrews, and bearings are properly lubricated.

Insufficient lubrication can cause binding that prevents smooth motion during commutation.

Test with reduced load

If possible, disconnect mechanical load and test field angle detection with motor running free to isolate mechanical vs. electrical issues.

Follow proper lockout/tagout procedures when disconnecting mechanical components.