Baumuller b maXX BM5800 - Setting Options of the Polynomial Filter

Controllers
Parameter manual b maXX BM5800
Document No.: 5.16029.03 Baumüller Nürnberg GmbH
442
of 814
3.7
3.7.2.3 Setting options of the polynomial filter
The polynomial filter can be combined from several single filters; available are the PT
1
filter, the notch filter, the PT
2
filter and the biquad filter. In total a filter can be used up to
the seventh order. The PT
1
filter is first order whereas the other filters are second order.
Consequently, for instance a PT
1
filter can be combined with three notch filters or three
PT
1
filters with on PT
2
filters and a biquad filter. The single filters are activated or deacti-
vated via the bits 4 to 13.
The PT
1
filters can be parameterized via the accordant limit frequency and the notch fil-
ters via the blocking frequency and the bandwidth. The three biquad filters can parame-
terize any filter type, such as notch filters with a defined notch depth and/or a defined
lowering. Also the PT
2
filter can be parameterized with this, hereby the numerator fre-
quency must be set to 0 Hz. Internally, the entire numerator is set to 1 this way.
The biquad filter is calculated with the following function:
The following terms apply:
n The filter amplitude increases from the cutoff frequency numerator f
Z
onwards.
n The filter amplitude decreases from the cutoff frequency denominator f
N
onwards.
n The slope is set via the damping D
Z
and D
N
.
NOTE!
If bit 2 of Z29.1– was not set, the filter coefficients must be set again when changing
the RT0 cycle time!
Fs
1
2f
Z

2
------------------
s
2

2D
Z
2f
Z
-----------
s 1++
1
2f
N

2
-------------------
s
2

2D
N
2f
N
-----------
s 1++
---------------------------------------------------------------=