Speed Deviation
Yaskawa · F7 Drive Programming
What does DEV mean?
A Speed Deviation (DEV) fault is triggered when the difference between the actual motor speed and the frequency reference command exceeds the configured deviation level (F1-10) for a time longer than F1-11. This signifies a discrepancy between the commanded speed and the actual motor speed, often due to mechanical load issues, encoder problems, or improper tuning of the speed control loop. Prolonged deviation can lead to process quality issues, mechanical stress on components, or inefficient operation.
Additional Steps
Steps 1–2 are listed in Priority Fix.
- 3
Adjust F1-10 (Excessive speed deviation detection level) and F1-11 (Excessive speed deviation detection delay time) to match the application's acceptable deviation tolerance and dynamic response requirements.
- 4
Ensure the motor and drive are correctly sized and tuned (e.g., PI gains) for the application's specific torque and speed demands.
- 5
Review F1-04 to confirm the desired stopping method (Ramp to stop, Coast to stop, Fast-Stop, Alarm Only) for DEV faults is selected.