231-8BA0

Access Motor Table Parameters

Press MOD key, select 'Machine Parameters', navigate to motor table for affected axis (%1), locate STR parameter.

Always backup machine parameters before making changes

Verify Encoder Specifications

Check encoder nameplate or documentation for correct line count (lines per revolution for rotary encoders, lines per mm for linear scales).

Using incorrect line count will cause positioning errors

Update STR Parameter

Enter correct line count value in STR field, save parameters, and perform controlled restart of TNC system.

Execute Reference Point Search

Run reference point procedure for affected axis to verify correct encoder signal interpretation.

Power Down and Lock Out

Safely shut down machine, engage all lockout/tagout procedures before accessing encoder components.

Never clean encoders while machine is powered - risk of electrical shock

Inspect Scale and Scanning Head

Visually examine linear scale tape or rotary encoder disc for scratches, contamination, or physical damage. Check scanning head alignment and cleanliness.

Clean with Approved Solvents

Use lint-free cloth with isopropyl alcohol to gently clean scale surface and scanning head optics. Avoid touching scale graduation area directly.

Heidenhain recommends specific cleaning procedures - consult encoder manual for material compatibility

Check Signal Quality

Power up system, use TNC diagnostic screens to monitor encoder signal amplitude and verify clean sinusoidal waveforms.

Visual Cable Inspection

Examine encoder cable along entire length for kinks, cuts, or damage. Pay special attention to areas with cable movement or stress.

Check cable routing through cable chains - improper installation causes premature failure

Connector Verification

Inspect encoder connectors at both ends for corrosion, bent pins, or loose connections. Ensure proper mating and locking mechanisms engaged.

Continuity and Isolation Testing

Using appropriate multimeter, test cable continuity for all conductors and verify isolation between signal pairs. Compare readings to cable specifications.

Heidenhain encoder cables have specific impedance requirements - use TDR testing for intermittent faults

Signal Monitoring

Connect oscilloscope to encoder signals at TNC input while manipulating cable to identify intermittent connection issues.

Swap Test with Known Good Axis

If possible, temporarily connect problematic encoder to different TNC encoder input channel to isolate hardware vs. encoder issues.

Check Input Module LEDs

Observe encoder input module status LEDs on TNC hardware - red or flashing indicators suggest input circuit problems.

TNC encoder modules have built-in diagnostics - check error logs for specific fault codes

Measure Input Voltages

Verify proper supply voltages to encoder input modules and check signal levels at TNC input terminals against specifications.

Document for Service Call

Record all test results, error codes, and symptoms for Heidenhain service technician - encoder input replacement requires factory training.

TNC encoder input modules contain precision analog circuits - replacement requires proper ESD procedures

Environmental Assessment

Check machine environment for excessive humidity, temperature fluctuations, or sources of electrical interference near encoder systems.

Seal Integrity Inspection

Verify encoder housing seals, cable glands, and connector sealing rings are intact and properly installed to prevent moisture ingress.

Heidenhain encoders have IP ratings - ensure installation meets environmental protection requirements

EMI Source Identification

Identify potential electromagnetic interference sources (VFDs, welders, high-current switching) and verify proper cable shielding and grounding.