230-0457

Check encoder signal quality

Access MOD 127 (Encoder Test) and monitor signal amplitude and quality while manually moving the axis. Look for signal dropouts or irregular patterns.

Signal amplitude should be between 0.6-1.4V pp for optimal performance

Inspect encoder scale and read head

Clean the glass scale with lint-free cloth and isopropyl alcohol. Check read head gap (typically 0.5mm ±0.1mm) and ensure no chips or contamination.

Power down machine before cleaning encoder components

Verify encoder cable integrity

Check encoder cable for damage, proper shielding connection, and secure connections at both encoder and TNC ends. Test cable continuity if necessary.

Test reference mark detection

Use MOD 126 (Reference Mark Test) to verify reference mark signal detection while slowly moving axis through reference position manually.

Verify reference direction parameter

Check MP1010.x (Reference cam/Reference mark) matches actual reference switch and encoder reference mark positions. Correct value depends on machine geometry.

MP1010 bit pattern determines search sequence - consult machine documentation for correct setting

Check maximum traverse distance

Verify MP1030.x (Maximum traverse path for reference-point approach) is set larger than actual distance needed to reach reference mark from any position.

Validate reference mark search parameters

Review MP1020.x settings for reference mark search velocity and ensure they match encoder specifications and mechanical capabilities.

Compare with working axis

If other axes reference properly, compare their machine parameters with the failing axis to identify discrepancies.

Test manual axis movement

Put machine in manual mode and test axis movement throughout full travel range. Check for binding, unusual noise, or resistance.

Ensure all safety systems are active during manual movement

Inspect way lubrication

Verify way oil system is functioning and ways are properly lubricated. Check oil level and distribution to affected axis.

Check for mechanical obstructions

Inspect axis travel path for chips, tooling, or other obstructions that could prevent reaching reference position.

Verify reference switch operation

Test reference limit switch activation and check MP1010.x configuration matches actual switch position and operation.

Check drive status and alarms

Review any active or recent drive alarms in the TNC alarm log and drive display. Clear any resettable drive faults.

Monitor following error

Use MOD 124 (Position values) to monitor following error during reference approach. Excessive following error indicates drive or mechanical issues.

Test axis response

Perform small incremental moves in both directions to verify drive responds properly to TNC commands before attempting reference sequence.

Verify motor and coupling

Check motor coupling for damage and ensure motor is properly connected and receiving power from the drive.

Reload machine parameters

Backup current parameters, then reload known good machine parameter set from backup or machine manufacturer's original configuration.

Perform TNC restart

Execute complete TNC restart (not just reset) to clear any temporary software issues that might affect referencing.

Check axis assignment

Verify MP100.x (Assignment of axes) correctly assigns the physical axis to the logical axis designation.

Update TNC software

If problem persists and other causes eliminated, consider TNC software update if newer version available with referencing improvements.