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.

Complete Troubleshooting Guide

1. 1

   Modify the operating sequence to prevent restarting the drive when induced voltage is present in the motor.

2. 2

   Enable the Speed Search at Start Selection by setting b3-01 = 1, or utilize external Speed Search commands (H1-xx = 61, 62).

3. 3

   If the fault persists after addressing sequence adjustments and implementing speed search, assume a drive hardware problem and proceed with replacing the drive unit.