Cause: Reference encoder calibration comes when the drive has lost or is unable to establish the correct alignment or zero position of the connected reference encoder.

REFC REF ENCODER CAL fault in Parker AC890 drive indicates an issue with the reference encoder calibration. This means the reference encoder requires calibration or its calibration has failed or been lost. This applies when the drive uses dual encoders—typically one on the motor (primary feedback) and another on the load or line (reference feedback), such as in winder, dancer, or gearbox applications.

Troubleshooting Steps:

• Check Encoder Wiring and Connections: Ensure the encoder cable is securely connected to both the drive and the encoder.
• Verify Encoder Type and Parameters: Using the drive's keypad or software interface, check the parameters related to the reference encoder.
• Perform Encoder Calibration: The Parker AC890 drive manual will outline the specific procedure for calibrating the reference encoder.
• Check for Mechanical Issues: If the calibration was previously successful but the fault has reappeared, inspect the mechanical coupling between the motor and the encoder for any signs of slippage or loosening.