231-C6F0

Access Machine Parameters

Navigate to MOD function → Machine Parameters → Channel-specific parameters → Axes/Spindles → Position encoder input settings for the affected axis.

Document current settings before making changes for rollback purposes.

Verify posEncoderInput/analogOffset Setting

Check parameter posEncoderInput/analogOffset matches encoder wiring documentation. Verify if encoder uses differential (±) or single-ended signals.

Incorrect offset settings can damage encoder electronics.

Cross-reference Encoder Documentation

Compare current parameter with encoder manufacturer specifications and machine electrical drawings to ensure proper analog offset configuration.

Test Configuration Change

After correcting analogOffset parameter, perform axis reference run and monitor for alarm recurrence during encoder amplitude test.

Check Current posEncoderType Setting

Navigate to machine parameters and locate posEncoderType for the affected axis. Note current setting (analog/digital/EnDat/etc.).

Use PLC program to display current encoder type setting for quick verification.

Identify Physical Encoder Type

Check encoder nameplate and cable connector type. EnDat encoders use different connectors than analog sine/cosine encoders.

Never assume encoder type without physical verification - mixing types can cause control damage.

Correct Parameter Setting

Set posEncoderType to match actual encoder: 0=incremental analog, 1=absolute analog, 2=EnDat, etc. based on TNC parameter documentation.

Verify Signal Quality

Use TNC diagnostic screens to monitor encoder signal amplitude and verify proper signal levels after parameter correction.

Visual Cable Inspection

Inspect encoder cable from motor to CC controller for physical damage, sharp bends, or pinch points. Check connector pins for corrosion or damage.

Power down system before disconnecting encoder cables to prevent damage.

Continuity Testing

Use multimeter to test continuity of encoder signal lines (A+, A-, B+, B-, Z+, Z-) and shield connection from motor to controller.

Test with cable flexed in different positions to identify intermittent breaks.

Signal Quality Measurement

Use oscilloscope to measure encoder signal amplitude at controller input. Sine/cosine signals should be 1Vpp ±20% with proper offset.

Compare signal quality at encoder output vs. controller input to isolate cable issues.

Cable Replacement

Replace encoder cable with proper Heidenhain-approved cable maintaining correct shield grounding and routing away from power cables.

Encoder Signal Analysis

Monitor encoder signals using TNC diagnostic display or oscilloscope. Look for distorted sine/cosine waves, amplitude variations, or DC offset issues.

Compare signal patterns between working and suspect axes for reference.

Temperature Correlation Test

Monitor alarm occurrence relative to machine warm-up cycle. Failing encoder electronics often show temperature-dependent behavior.

Allow proper warm-up time before concluding encoder failure.

Encoder Substitution Test

If possible, temporarily connect known good encoder to isolate encoder vs. controller issues. Use same encoder type and parameter settings.

Document all parameter changes during substitution testing for proper restoration.

Encoder Replacement Planning

Order exact replacement encoder with matching resolution and interface type. Plan for axis re-commissioning and reference point establishment.