Siemens SINAMICS S120 Function Manual page 89

General low-pass with reduction
Table 3-6 Example of general low-pass with reduction
STARTER filter parameters
Characteristic frequency f
= 500 Hz
Damping D = 0.7
Reduction Abs = –10 dB
Conversion to parameters for general order filters
S Numerator natural frequency f
S Numerator damping f
S Denominator natural frequency f
S Denominator damping D
Transfer function general 2nd-order filter
s
2pf Z
+
H
(s)
s
2pf N
s + jw + j @ 2pf
S Numerator natural frequency f
S Numerator damping D
S Denominator natural frequency f
S Denominator damping D
Table 3-7 Example of general 2nd-order filter
STARTER filter parameters
Numerator frequency f = 500 Hz
Z
Numerator damping D = 0.02 dB
Z
Denominator frequency f
900 Hz
Denominator damping D
N
0.15 dB
© Siemens AG 2006 All Rights Reserved
SINAMICS S120 Function Manual, 03/2006 Edition
Amplitude log frequency curve
Abs
f
+
Abs
Z
Abs
10
40
N
2
2D Z
) @ s ) 1
2pf Z
2
2D N
) @ s ) 1
2pf N
Z
N
Amplitude log frequency curve
=
N
=
Phase frequency curve
= f (start of reduction)
Z Abs
N
Z
N
Phase frequency curve
Operating Modes
Servo control
3-89