26022

Access Diagnostics > Machine Data > Axis-Specific > MD20050 for the affected axis. Verify encoder type is not set to 0 (simulated). Correct value should be 1 (incremental) or 2 (absolute), based on actual hardware installed.

Do not modify MD20050 while axis is moving or referenced.

Check MD20051 (EncSimulationMode) and ensure it is set to 0 (disabled). If set to 1 or higher, encoder simulation is forcing virtual feedback mode.

Verify physical encoder hardware is connected to the axis module (analog/digital input card or integrated encoder input on drive). Use PLC > I/O Diagnosis to confirm encoder signal presence at NCK input.

Once hardware encoder is confirmed present and MD20050/MD20051 corrected, execute automatic axis calibration via machine menu or G-code (G37 reference point search) to re-establish encoder measurement.

Ensure axis is in safe position away from overtravel limits before running reference point search.

Navigate to Diagnostics > Axis > Encoder Status for affected axis. Check encoder signal value fluctuation in real-time. Stationary or unchanging values indicate no hardware feedback despite MD20050 hardware setting.

Inspect encoder connector at drive module and encoder cable for loose connections, corrosion, or physical damage. Reseat encoder connectors firmly. Verify cable shield continuity with multimeter if available.

Power down drive before performing connector inspection.

Check MD20060 (EncResolution) and MD20061 (EncPolarity) match encoder specifications. Incorrect resolution can cause measurement failure. Verify in axis-specific Parameters > Feedback > Encoder menu.

If encoder remains unresponsive, temporarily set MD20051 (EncSimulationMode) to 1 to allow axis operation in simulation mode. Replace encoder hardware and restore MD20050 to hardware mode (1 or 2) once new encoder installed and validated.

Simulated encoder mode degrades position accuracy and prevents precision applications. This is temporary troubleshooting only.

Verify MD32010 (AutoRefSearch) is enabled (value > 0) and MD32000 (RefpointType) is set to mode 3 (measured reference point) or appropriate mode for your machine. Navigate Diagnostics > Machine Data > Axis > Reference Point.

Confirm MD32050 (MeasVelocity) and MD32051 (MeasDistance) contain valid calibration parameters for measurement routine. Zero or negative values will cause measurement failure and fallback to simulated mode.

Clear any active axis faults via machine menu (Axis Reset or CTRL+ALT+R). Retry encoder measurement/reference point search. Monitor Diagnostics > Axis > Measurement Status during execution.

Ensure axis is physically positioned away from mechanical limits before retry.

If alarm 26022 persists after parameter validation, check for conflicting MD20070 (EncFilterTime) or other encoder quality parameters. Excessive filter time can mask hardware encoder signals. Review full axis encoder parameter block in machine data backup.