HEIDENHAIN MANUALplus 620 Technical Manual page 859

Recommended
types of filters
Possible
multifunction filter
settings
January 2012
Experience has shown that the band rejection of the multifunction filters is to
be used for damping oscillations in the speed controller.
On the other hand, the tendency of the position controller to oscillate should
be counteracted with IPC (Integral Phase Compensation). Only if this
adjustment does not lead to the desired result can the multifunction filters
such as the phase increase (better, since it does not facilitate oscillations at
lower frequencies as much) or the band-rejection filter be used.
Since the ambient conditions can be so different, the use of the filters must
be checked separately in every case. The TNCopt PC software from
HEIDENHAIN should always be used, so that the sequence of the adjustment
matches the ideal case. This manual can only present recommended
guidelines and procedures.
Selection of filter type:
0 = Filter not active
1 = PT2 low-pass filter (speed
controller)
2 = Band-rejection (speed ctrl.)
3 = Phase increase (speed ctrl.)
11 = PT2 low-pass filter (position
controller)
12 = Band-rejection (position ctrl.)
13 = Phase increase (position ctrl.)
PT2 low-pass filter: No effect
Band rejection: Damping [dB]
Phase increase: Phase [0 - 90°]
PT2 low-pass filter: Corner
frequency [Hz]
Band-rejection: Center frequ. [Hz]
Phase increase: Center frequency
[Hz]
PT2 low-pass filter: No effect
Band-reject.: Bandwidth [Hz]
Phase increase: Bandwidth [Hz]
The filters can be used in the position controller or speed controller as desired.
For example, the second filter can be used although the first filter is not active.

In MP_vCtrlFiltType1...5, define the filter type and specify whether the
filter is to take effect in the speed controller or in the position controller. The
other parameters to be entered depend on the filter type:

Enter MP_vCtrlFiltFreq1...5 to set a PT2 second-order time-delay
element. Enter a cutoff frequency of 3 dB as parameter value.
 The parameters MP_vCtrlFiltFreq1...5, MP_vCtrlFiltBandWidth1...5 and
MP_vCtrlFiltDamping1...5 are required to set a band-rejection filter.
6.16 The Control Loop
Filters 1 to 5
MP_vCtrlFiltType1...5
MP_vCtrlFiltDamping1...5
MP_vCtrlFiltFreq1...5
MP_vCtrlFiltBandWidth1...5
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