231-C4E0

Check Encoder Type Configuration

Access MOD function, select 'Machine Parameters', navigate to MP7520 (Encoder type) and verify the encoder type matches the physically installed encoder.

Document the encoder model number from the physical label before checking parameters

Verify Field Angle Determination Setting

Check MP7560 (Field angle determination). For EnDat encoders use value 1, for incremental encoders with commutation tracks use value 0, for encoders without commutation use value 2.

Incorrect settings can cause motor damage during commutation

Update Parameter and Test

Set MP7560 to the correct value for your encoder type, save parameters with 'PGM MGT' + 'MOD' + 'SAVE', then perform controlled axis movement test.

Always test with low feed rates initially after parameter changes

Check EnDat Communication Status

Access 'Manual Operation' mode, press 'POS' key, check if absolute position values are displayed correctly and updating smoothly during manual movement.

Never move axes manually without ensuring proper encoder feedback

Inspect Encoder Cable and Connections

Power down system, check encoder cable for damage, verify connector pins are clean and properly seated at both encoder and drive ends.

Use contact cleaner on encoder connectors - contamination is a common cause of EnDat communication errors

Test Encoder Signal Quality

Access diagnostic screens via 'MOD' function, check encoder signal amplitude and frequency response during slow axis movement.

EnDat signals should show consistent amplitude without dropouts or noise spikes

Verify Motor Pole Pair Setting

Check motor nameplate for pole pair count, compare with MP7570 setting in machine parameters. Common values are 3, 4, or 5 pole pairs for servo motors.

Pole pairs = (Motor poles ÷ 2) - often confused with total pole count

Check Commutation Offset Value

Review MP7580 (Commutation offset) - should be 0 for most EnDat encoders with integrated commutation, or specific value from motor documentation for incremental systems.

Incorrect commutation offset can cause motor overheating and damage

Perform Commutation Calibration

If parameters are correct but alarm persists, run automatic commutation calibration through 'Test Run' menu to re-establish proper field angle reference.

Ensure motor shaft can rotate freely before starting automatic commutation procedure

Check Servo Drive Status LEDs

Examine servo amplifier front panel LEDs for error indicators, compare LED patterns with drive manual to identify specific hardware faults.

High voltage present - follow lockout/tagout procedures before accessing drive hardware

Verify Drive Supply Voltages

Measure DC bus voltage and control supply voltages at servo drive terminals, ensure they meet specifications in drive documentation.

Low DC bus voltage can cause intermittent encoder processing errors

Test with Known Good Encoder

If available, temporarily connect a verified working encoder of the same type to isolate whether the issue is drive-related or encoder-related.

Keep a spare encoder cable for troubleshooting - cable faults often mimic encoder failures

Check Current Operating Mode

Verify TNC is in appropriate mode for servo operation - exit any active measuring cycles, tool measurement, or special functions that may restrict servo operation.

Press 'END' key multiple times to ensure you're at the main operating level

Review Active M-Functions

Check if any M-functions related to spindle orientation or special servo modes are active that might conflict with normal field angle determination.

Some M-functions remain active between program cycles and must be explicitly cancelled

Reset Servo System

Perform controlled servo system reset through 'MOD' function to clear any temporary mode restrictions and reinitialize field angle determination.

Document current work offset and tool data before servo reset as some values may need to be re-established