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9.2.3. Digital Filter
Caution : • Inserting multiple filters may cause phase inversion of velocity loop in some
systems, resulting in unstable operation.
• Do not insert more than two filters. Setting a filter frequency too low may
cause hunting, etc.; set the frequency to 100 Hz or above.
Parameters for digital filter setting
u Parameters : FP, FS, NP, NS
l Sets filter frequency in the velocity loop.
l The filters are useful for eliminating audible noise and vibration due to mechanical resonances.
Table 9-12: Parameter function
Parameter Function Shipping set
FP Sets the primary low-pass filter frequency. FP0
FS Sets the secondary low-pass filter frequency. FS0
NP Sets the primary notch filter frequency. NP0
NS Sets the secondary notch filter frequency. NS0
l Refer to “12. Command and Parameter” for more details.
Figure 9-28: Digital filter block diagram
Velocity
command
loop gain
Velocity data
integrator
low-pass
filter
low-pass
filter
notch
filter
+
–
notch
filter
NSNPFSFPVI
VG
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