Rockwell Automation Publication 2198-UM004D-EN-P - December 2022 259
Chapter 10 Modes of Operation
Resonance Suppression (Notch Filter, Speed Mode)
When resonance occurs, it can be naturally occurring resonance present on the
mechanism or can be as a result of increasing the control loop gains beyond
the limits of the mechanism. Mitigating these two factors can improve the
situation. In addition, parameter Low-pass Filter ID210 (P2.023) and 5 notch
filters (see Table 95 on page 259
) are provided to suppress the resonance if the
control parameters remain unchanged.
The drive provides two types of resonance suppression, one is a notch filter
and the other is a low pass filter. See the following diagrams for the results of
suppression by each type.
As shown in the previous two examples, if the value of parameter
ResonanceSuppressionLowPassFilterTime ID210 (P2.025) is increased from 0,
the bandwidth (BW) becomes smaller. Although it solves the problem of
resonance, it also reduces the response bandwidth and phase margin, so either
the control loop gains have to be lowered, or the system can become unstable.
If the resonance frequency is known, you can mitigate the suppression by
using the Notch filter, which is better than the low pass filter in this case. If the
resonance frequency drifts along with time or other causes and the drifting
amount is too great, using a notch filter is not recommended.
Table 95 - Relevant Parameters
Parameter Name
ID208 (P2.023) NotchFilter1Frequency
ID209 (P2.024) NotchFilter1Depth
ID226 (P2.043) NotchFilter2Frequency
ID227 (P2.044) NotchFilter2Depth
ID228 (P2.045) NotchFilter3Frequency
ID229 (P2.046) NotchFilter3Depth
ID254 (P2.095) NotchFilter1QValue
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