231-AC00

Access encoder diagnostics

Navigate to MOD function → Encoder Test → select affected axis encoder to view real-time amplitude values in EnDat diagnostics screen.

Normal amplitude should be between 0.8-1.2V for most HEIDENHAIN encoders

Measure air gap with feeler gauge

Use 0.1mm feeler gauge to check air gap between scanning head and encoder scale. Gap should be 0.1-0.3mm depending on encoder type.

Power down system before mechanical adjustments to prevent encoder damage

Adjust scanning head position

Loosen scanning head mounting screws and adjust position to achieve proper air gap. Retighten to specified torque and verify amplitude in encoder diagnostics.

Make small adjustments - even 0.05mm changes significantly affect signal amplitude

Inspect encoder surfaces

Visually examine encoder scale and scanning head for oil film, coolant residue, or debris accumulation using proper lighting.

Never touch encoder scale graduation area with bare hands - oils cause permanent damage

Clean with approved solvents

Use HEIDENHAIN cleaning kit or isopropyl alcohol (99%) with lint-free cloth to clean scale and scanning head surfaces following manufacturer procedures.

Clean in direction perpendicular to scale graduations to avoid damage

Verify signal quality

Return to MOD → Encoder Test and monitor amplitude values while manually moving axis through full travel to confirm consistent readings.

Amplitude should remain stable within ±10% throughout axis travel

Check encoder supply voltage

Access Service menu → Voltage Monitor → Encoder Supply and verify 5V rail is within ±5% tolerance (4.75-5.25V).

Voltage should be stable under load - fluctuations indicate power supply issues

Inspect encoder cable

Check encoder cable for damage, proper shielding connection, and secure connections at both TNC and encoder ends using multimeter continuity test.

Disconnect power before cable inspection to prevent electrical damage

Test with known good cable

Temporarily substitute encoder cable with known good spare and test for alarm recurrence to isolate cable-related voltage issues.

Keep spare encoder cables calibrated and properly stored to avoid introducing new variables

Verify encoder type parameters

Check MOD → Machine Parameters → Axis Parameters and confirm encoder type (MP1420) matches actual installed encoder model and specifications.

Cross-reference encoder label with HEIDENHAIN catalog to ensure exact parameter match

Review signal monitoring parameters

Examine MP1430 (encoder monitoring) settings and MP1425 (signal amplitude limits) to ensure they match encoder specifications.

Incorrect monitoring parameters can cause false alarms or mask real encoder problems

Reset encoder learning values

Navigate to MOD → Encoder → Initialize and perform encoder reference point learning to establish proper signal baselines.

Perform learning with machine at operating temperature for most accurate results