230-01A1

Access machine parameter menu

Press MOD key, enter machine parameter mode using Setup > Machine Parameters menu.

Machine parameter changes require proper authorization and can affect machine operation.

Check encoder interface parameters

Navigate to MP1xxx series parameters for the affected axis. Verify MP1010 (encoder interface type) matches actual encoder hardware (EnDat, 1Vpp, TTL, etc.).

Document original parameter values before making changes.

Verify encoder connection parameters

Check MP1020 (encoder input assignment) and MP1030 (encoder resolution) match the physical encoder specifications from encoder nameplate.

Cross-reference encoder model number with Heidenhain encoder database for correct parameters.

Restart control system

Perform controlled shutdown and restart of TNC to activate new parameter settings.

Ensure all programs are saved before restart.

Power down and inspect encoder cable

Turn off machine power and visually inspect encoder cable for damage, kinks, or wear along entire length from encoder to control cabinet.

Always follow LOTO procedures before accessing electrical connections.

Check connector integrity

Inspect encoder connector at both encoder head and control cabinet. Clean contacts with appropriate contact cleaner and ensure proper seating.

Use dielectric grease on outdoor or high-humidity installations.

Perform cable continuity test

Using multimeter, test continuity of all encoder cable conductors from encoder connector to control cabinet connector. Check for shorts between conductors.

Refer to encoder cable pinout diagram in machine documentation for proper conductor identification.

Replace cable if faulty

If continuity test fails, replace encoder cable with identical Heidenhain-approved cable maintaining proper routing and strain relief.

Use only shielded cables with proper impedance rating for encoder type.

Check encoder LED status

Observe encoder LED indicators (if present) during power-up. Red LED typically indicates encoder fault, green indicates normal operation.

Some encoders have diagnostic LEDs visible through transparent housing.

Test encoder with PWM 21 software

Connect encoder to Heidenhain PWM 21 testing device or use TNC encoder test function in Setup > Encoder Test menu to verify encoder signal quality.

PWM 21 provides detailed signal analysis including amplitude, offset, and interpolation errors.

Inspect encoder mechanical condition

Check encoder mounting for looseness, contamination on scale/code disk, and proper air gap (typically 0.5-1.0mm for optical encoders).

Do not touch encoder scale or code disk surfaces - oils from skin can cause permanent damage.

Replace encoder if defective

If encoder fails tests, replace with identical Heidenhain encoder maintaining proper mounting alignment and air gap specifications.

Record encoder serial number and calibration data before removal for warranty purposes.

Check encoder input module status

Access TNC diagnostic menu via Setup > Diagnosis > Encoder Inputs to view real-time encoder input status and error flags.

Green status indicates good signal, red indicates fault condition.

Test with known good encoder

Temporarily connect a known working encoder from another axis to the suspected faulty input to isolate whether issue is encoder or input module.

Ensure encoder types are compatible before swapping connections.

Inspect encoder input module

Visually inspect encoder input PCB for obvious damage, burned components, or loose connections. Check module seating in backplane.

Look for discolored components or unusual odors indicating thermal damage.

Contact Heidenhain service

If encoder input module is suspected faulty, contact Heidenhain service for module replacement and calibration procedures.

TNC encoder input modules require factory calibration and should only be replaced by qualified technicians.