Danfoss VLT AutomationDrive FC 300 Programming Manual page 109

Parameter Descriptions
7-06 Speed PID Lowpass Filter Time
Range: Function:
the cut-off frequency for the low-pass filter
will be 1/0.1= 10 RAD/s., corresponding to
(10/2 x π) = 1.6 Hz. The PID regulator only
regulates a feedback signal that varies by a
frequency of less than 1.6 Hz. If the feedback
signal varies by a higher frequency than 1.6
Hz, the PID regulator does not react.
Practical settings of 7-06 Speed PID Lowpass
Filter Time taken from the number of pulses
per revolutions from encoder:
Encoder PPR
512
1024
2048
4096
NOTE
Severe filtering can be detrimental to dynamic
performance.
This parameter is used with 1-00 Configuration Mode [1]
Speed closed loop and [2] Torque control.
The filter time in flux sensorless must be adjusted to
3-5 ms.
®
VLT AutomationDrive Programming Guide
Feedback
7-06 Speed PID
Lowpass Filter Time
10 ms
5 ms
2 ms
1 ms
Feedback
Illustration 3.45 Feedback Signal
®
MG33MG02 - VLT is a registered Danfoss trademark
Disturbed feedback signal
Lowpass lter
f = 10 Hz
g
Filtered feedback signal
3
0.6 t (Sec.)
0.6 t (Sec.)
107
3