Delta ASD-B2-0121-F, User Manual

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Control Mode of Operation ASDA-B2-F
6-22
September, 2015
6
Resonance suppression with low-pass filter:
Resonance Point
B.W
Resonance
Frequency
Frequency
Gain
+
Gain
Frequency
0 db
Attenuation Rate -
3dB
Low-pass filter
Cut-off frequency of
low-pass filter
=1000/P2-25Hz
=
Resonance condition is
suppressed
B.W
Resonance
Frequency
Gain
Frequency
When the value of low-pass filter (P2-25) is increased from 0, B.W. becomes smaller. Although it
improves the situation of resonance, the response bandwidth and phase margin are reduced as
well. Also, the system becomes unstable. If users know the resonance frequency, notch filter
(P2-23 and P2-24) can directly eliminate the resonance. In this case, notch filter will be more
helpful than low-pass filter. However, if the resonance frequency drifts because of time or other
factors, notch filter will not be preferable.