Delta ASD-B2-0121-B, User Manual

Page: 139 / 313

Chapter 6 Control Modes of Operation
6-30
Revision June 2010
Use Notch Filter to suppress resonance
0db
Notch Filter
Attenuation
Rate P2-24
Resonance
Frequency .
Resonance
Point Gain
Frequency
.
Gain
Frequency
Gain
Frequency
Low-pass
Frequency
Low-pass
Frequency
Resonance
Frequency
P2-23
Resonance
conditions
is suppressed
Resonance
Frequency
Use Low-pass Filter to suppress resonance
Low-pass Filter
Cut-off Frequency
of Low-pass Filter
= 10000 / P2-25 Hz -
0db
Resonance
conditions
is suppressed
.
.
Gain
Frequency
Gain
Frequency
Gain
Frequency
Low-pass
Frequency
Low-pass
Frequency
Resonance
Frequency
Attenuation
Rate -3db
Resonance
Point
Resonance
Frequency
When the low-pass filter (parameter P2-25) is adjusted from 0 to high value, the value of
Low-pass frequency will become smaller (see the figure on page 6-26). The resonant
condition is improved but the frequency response and phase margin will also decrease
and the system may become unstable. Therefore, if the users know the resonance
frequency, the users can eliminate the resonance conditions directly by using notch filter
(parameter P2-23, P2-24). Usually, if the resonant frequency can be recognized, we
recommend the users can directly use notch filter (parameter P2-23, P2-24) to eliminate
the resonance. However, if the resonant frequency will drift or drift out of the notch filter
range, we recommend the users not to use notch filter and use low-pass filter to improve
resonant conditions.