Rockwell Automation 20D PowerFlex 700S with Phase I Control Reference Manual - Manual (Page 57)

Rockwell Automation Publication PFLEX-RM002D-EN-E - August 2013 57
Detail Drive Configuration and Operation Chapter 1
Figure 16 - Bode Plot and Time Domain of Lag
The lag configuration is good for eliminating unwanted noise and disturbance
such as backlash. There are two lead-lag blocks used in the speed regulator loop.
One is in the forward path and the other is in the feedback path.
For moderate filtering:
Set Kn=0.7, Wn=0.35
For Heavy filtering:
Set Kn=0.5, Wn=20
Both the Forward and Feedback filters can be set to the same value to increase
their effectiveness.
Lead-Lag Filter “Lead”
When Kn is greater than one (Kn>1), the lead-lag filter operates as lead filter.
The original equation is re-written into a term that can be used to utilize the lead
function. Wn is divided throughout the equation. Two new terms are developed.
Kn Wn
Forward Path Parameter 95 [SRegOut FiltGain] Parameter 96 [SReg Out Filt BW]
Feedback Path Parameter 93 [SRegFB Filt Gain] Parameter 94 [SReg FB Filt BW]