08.96 12 Functional Descriptions
12.33.3 Current setpoint filter
Filter in the case of resonance at and above the controller stability limit
Low-pass
– With resonance bundle
– Distribution of resonance phenomena (dependent on traversing direction, speed)
Low-pass as current setpoint filter
A low-pass filter is the better solution in cases where a peak occurs in the amplitude response
that is not linked to a fixed frequency, but wanders under different conditions. With a low-pass
filter, the signal above the entered natural frequency is damped. Reduced damping results in
less phase rotation below the natural frequency and thus to a greater phase margin.
Amplitude response
Magnitude
[dB]
log f [Hz]
10
2
10
3
10
3
0
-3
-10
-20
-30
Phase response
Phase
angle
log f [Hz]
10
2
10
3
180
90
0
-90
-180
0.2
1.0
0.5
1.0 0.5
0.2
Fig. 12-4 Low-pass behaviour at natural frequency of 1000 Hz
and variation in damping of 0.2, 0.5 and 1.0
© Siemens AG 1992 All Rights Reserved 6FC5197- AA50
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SINUMERIK 840C (IA)