Speed Feedback Loss

What does SPF mean?

A loss of speed feedback has been detected. This means the drive is no longer receiving valid speed information from its encoder or resolver. This is critical for closed-loop speed control and can lead to unstable motor operation or a controlled shutdown. If left unresolved, accurate speed control is impossible.

Additional Steps

Steps 1–2 are listed in Priority Fix.

1. 3

   Verify the speed feedback parameters in the drive (e.g., encoder type, pulses per revolution).

2. 4

   Test the encoder/resolver output signals with an oscilloscope if possible.

3. 5

   Ensure the encoder power supply from the drive is present and stable.