Cause : ULC underload comes when selected signal has fallen below the user underload curve. A8BF warning in ABB ACS880 drive indicates a potential underload condition related to the user-defined load curve (ULC) for the motor.

• Check for any operating conditions decreasing the monitored signal (for example, loss of load if the torque or current is being monitored).
• Check the definition of the load curve (parameter group 37 User load curve).