Current Offset Fault

What does CoF mean?

This fault occurs if the drive attempts to start operation while residual induced voltage remains in the motor (e.g., during coasting to a stop or immediately after fast deceleration). Additionally, it can signify a drive hardware problem, where the current offset value exceeds the permitted setting range during the drive's automatic adjustment process. If not resolved, this can lead to incorrect motor control or further damage to the drive hardware.

• Attempting to restart the motor before it has fully come to a stop, encountering residual back EMF.
• Incorrect C2-01 (Flying Start Method Selection) if attempting a 'flying start' into a spinning motor.
• Internal current feedback sensor offset drift or calibration error within the drive hardware.
• Fast deceleration cycles followed immediately by a start command without sufficient settling time.
• Malfunctioning current sensing circuit board inside the drive.

Click steps to track your progress.

1. 1

   Ensure the motor has completely stopped (0 RPM, verify with U1-02) before issuing a new start command.

2. 2

   Adjust C2-01 (Flying Start Method Selection) to '1' (Speed Search) if restarting into a spinning motor is required.

3. 3

   Cycle power to the drive (full power down for 30 seconds) to reset internal control circuits.

4. 4

   Monitor current feedback values (U1-03, U1-04, U1-05) at motor standstill to check for non-zero offset.

5. 5

   Consult drive technical support for potential internal current sensor calibration procedures if suspected.