Drive A1 Submenu
57
Figure 34: Speed Deviation Example for
CLOSED LOOP (U9)
Figure 35: Speed Deviation Example for PM
(U9)
NOTCH FILTER FRQ
i,ii
(Notch Filter Center Frequency)
This parameter determines the notch filter
center frequency.
Notch Filter
Although originally created for gearless
applications where elevator rope resonance is
sometimes an issue, this filter affects the
torque command output of the speed regulator
and will filter out specific frequencies. By
filtering a specific frequency, the speed
regulator will avoid exciting a mechanical
resonance if one exists at that frequency.
There is attenuation across a range of
frequencies, not just at the set frequency, but
also to a lesser degree. The filter starts
attenuation at frequencies lower than the notch
frequency set point. When the notch
frequency is set to low values (less than 10
Hz), the filter can interfere with the desired
response of the drive. This can be exhibited
by minor increase in the rollback of the drive at
start and some deterioration in the ability of the
drive to track an s-curve reference. Generally,
this would not be an issue if the notch
frequency were set at or above 10 Hz.
Speed Feedback
Speed Deviation Fault Level
Speed Deviation Fault Level
Speed Deviation Alarm Level
Speed Deviation Alarm Level
Speed Deviation Low
Level
Speed Reference
30
25
20
Frequency
(Hz)
Attenuation
(dB)
1
10
100
15
10
5
0
Notch Filter Example
settings:
NOTCH FILTER FRQ (A1) = 20Hz
NOTCH FILT DEPTH (A1) = 50% and 100%
Speed Deviation High
(Speed Deviation Alarm)
Speed Deviation Low
Speed Deviation High
(Speed Deviation Alarm)
Speed
Reference
Speed Feedback
