Cause : Excessive Speed Deviation comes when the speed deviation has been greater than the setting in F1-10 for longer than the setting in F1-11.

1. The load is too large. Reduce the load.
2. The acceleration time and deceleration time are too short. Lengthen the acceleration time and deceleration time.
3. The load is locked. Check the mechanical system.
4. The settings in F1-10 and F1-11 aren't appropriate. Check the settings in F1-10 and F1- 11.
5. Brake is applied to the motor. Check for open circuit when using brake (motor).