Noise Error Rate and Filtering

If you are using feedback filtering, this topic is important to know.

When the axis detects feedback noise that exceeds the Noise Error Rate axis parameter, it estimates the position for a few loop times. It also “resets” the feedback filtering, which can cause the filtered actual position and actual velocity to momentarily read wrong values. This will appear as a “bobble” in the plot, and will cause problems with the motion control.

To avoid this problem, set the Noise Error Rate parameter to a value much larger than the expected noise. Keep in mind that this parameter goes off the actual noise, not the filtered noise. You can look at the Counts or Volts or Current in the plot to see the actual noise. The actual noise is the noise in the Counts, Volts, or Current, multiplied by the Position Scale.

This problem only applies if you have set the Position Filter Type and/or Velocity Filter Type axis parameters to Low Pass.

Delta Computer Systems Website