905-27EA

Access servo parameters

Navigate to MOD → Machine Parameters → Servo Parameters and check MP7610 (Position monitoring window) and MP7611 (Velocity monitoring window) for the affected axis.

Document current parameter values before making changes

Inspect mechanical coupling

Power down machine and manually inspect motor coupling, timing belt tension, and pulley alignment. Look for worn teeth, belt stretching, or loose coupling connections.

Ensure machine is properly locked out and tagged out before mechanical inspection

Perform coupling test

Use TNC diagnostic function Test Run → Servo Test to compare motor encoder feedback with linear scale position during slow axis movement.

Run test at 10% rapid traverse to minimize mechanical stress

Replace damaged components

Replace worn coupling, belt, or pulley components and re-tension according to machine manufacturer specifications.

Improper belt tension can cause premature failure or continued alarms

Check encoder signals

Access TNC Test Run → Position Values → Encoder Test and monitor motor encoder signals (REF, A, B channels) for noise, dropouts, or amplitude variations.

Compare signal quality between all axes to identify abnormal patterns

Inspect encoder cables

Check motor encoder cable routing, connections at motor junction box, and cable condition in drag chains for damage, contamination, or loose connections.

Use proper ESD precautions when handling encoder connections

Clean encoder assembly

Remove motor encoder cover and clean encoder disk/reader head with appropriate solvents, ensuring no debris interferes with optical or magnetic sensing.

Use lint-free cloths and encoder-specific cleaning solutions only

Verify encoder parameters

Check MP6010 (Encoder type) and MP6020 (Lines per revolution) match the installed motor encoder specifications in Machine Parameters.

Incorrect encoder parameters can cause permanent axis positioning errors

Check servo amplifier status

Navigate to TNC Diagnosis → Servo Diagnosis and review amplifier status, temperature readings, and fault history for the affected axis drive.

Note any recurring fault patterns or thermal cycling issues

Verify power supply voltages

Measure DC bus voltage, +/-15V encoder supply, and +24V logic supply at servo amplifier terminals using appropriate test equipment.

High voltage present - use proper PPE and follow lockout procedures

Perform amplifier diagnostics

Run built-in servo amplifier self-test functions and check for internal fault codes or parameter corruption in the drive memory.

Compare parameter backup files with current settings to identify corruption

Reset and recalibrate

Perform servo amplifier factory reset, reload machine-specific parameters, and run TNC automatic servo optimization routine.

Backup all parameters before reset - improper settings can damage machine components

Review monitoring parameters

Check MP7610 (Position monitoring), MP7620 (Velocity monitoring), and MP7630 (Acceleration monitoring) values against machine manufacturer specifications.

Overly tight monitoring windows can cause nuisance alarms during normal operation

Analyze servo performance

Use TNC Trace function to record actual vs. commanded position during typical machining operations and identify monitoring parameter adequacy.

Ensure trace recording doesn't interfere with critical machining operations

Adjust monitoring windows

Gradually increase monitoring window parameters while maintaining adequate safety margins for mechanical fault detection.

Increase parameters by 10-20% increments and test thoroughly between adjustments

Validate parameter changes

Run comprehensive axis movement tests including rapid traverse, positioning, and machining cycles to confirm alarm resolution without compromising safety.

Excessively loose monitoring parameters may mask actual mechanical problems