Speed Deviation

What does dEv mean?

This minor fault occurs when the deviation between the speed reference and the actual speed feedback (typically from a PG option card) exceeds the threshold set in F1-10 for a duration longer than F1-11. Common causes include excessive load, improperly set acceleration/deceleration times, mechanical lock-ups, or incorrect parameter scaling. Failure to resolve this can lead to unstable motor operation, mechanical stress, or an inability to maintain desired process speeds.

Additional Steps

Steps 1–2 are listed in Priority Fix.

1. 3

   Inspect the machine for any mechanical lock-ups or obstructions that prevent free movement.

2. 4

   Verify and adjust the settings of parameters F1-10 (speed deviation threshold) and F1-11 (deviation time limit).

3. 5

   If using terminal RP for speed feedback, ensure H6-02 is set to the correct speed feedback signal frequency at maximum motor speed and adjust H6-03 to H6-05 as needed. Confirm the motor brake is releasing properly and not engaging unexpectedly.