Beckhoff EP3356-0022 Documentation page 72

Commissioning/Configuration
Overview of conversion times
Filter Set- Value
tings
Filter deacti- -
vated
0 FIR 50 Hz
1 FIR 60 Hz
2 IIR1
3 IIR2
4 IIR3
5 IIR4
6 IIR5
7 IIR6
8 IIR7
9 IIR8
10 Dynamic IIR
11 PDO Filter fre-
quency
Filter and cycle time
If the FIR filters (50 Hz or 60 Hz) are switched on, the process data are updated maximally with the
specified conversion time (see table). The IIR filter works cycle-synchronously. Hence, a new mea-
sured value is available in each PLC cycle.
At which point the filters can be adjusted is described in the chapter "Object description and
parameterization" for example under index 0x8000:12.
IIR filter
Differential equation: Y
a = (see table), b
0
Dynamic IIR Filter
The dynamic IIR filter automatically switches through the 8 different IIR filters depending on the weight
change. The idea:
• The target state is always the IIR8-Filter, i.e. the greatest possible damping and hence a very calm
measured value.
• In the input variable changes rapidly the filter is opened, i.e. switched to the next lower filter (if still
possible). This gives the signal edge more weight and the measured value curve can follow the load
quickly.
• If the measured value changes very little the filter is closed, i.e. switched to the next higher filter (if still
possible). Hence the static state is mapped with a high accuracy.
• The evaluation as to whether a downward change of filter is required or whether an upward change is
possible takes place continuously at fixed time intervals.
Parameterization takes place via the CoE entries 0x8000:13 and 0x8000:14 [} 104]. Evaluation takes place
according to 2 parameters:
72
PDO update PDO update
time EL3356 time
EP3356-0022/
EL3356-0010
min. 10 ms Cycle-synchro-
nous,, min.
100 µs
min. 10 ms 312.5 µs
min. 10 ms 260.4 µs
Cyclesyn- Cycle-synchro-
chronous (up to nous (up to min.
min. 10 ms up- 100 µs)
date)
min. 10 ms 1/PDO
Value[Hz]*64
= X * a + Y * b
n n 0 n-1
= 1 - a
1 0
Version: 1.1.0
Filter property Limit fre-
quency (-3 dB)
[Hz] (typ.)
- -
50 Hz notch fil- 22 Hz
ter
60 Hz notch fil- 25 Hz
ter
Low-pass 2000 Hz
Low-pass 500 Hz
Low-pass 125 Hz
Low-pass 30 Hz
Low-pass 8 Hz
Low-pass 2 Hz
Low-pass 0.5 Hz
Low-pass 0.1 Hz
The filter changes dynamically between the filters IIR1 to IIR8
Notch filter with ca. 0,443 * PDO
adjustable fre- Value [Hz]
quency
with a + b = 1
1 0 1
Comment Rise time
10-90 % [s] (typ.)
- -
Typ. conversion 0.013
time 312.5 µs
Typ. conversion 0.016
time 260.4 µs
1
a =1/2 = 0.5 0.0003
0
2
a =1/2 = 0.25 0.0008
0
4
a =1/2 = 62.5e- 0.0035
0
3
6
a =1/2 = 15.6e- 0.014
0
3
8
a =1/2 = 3.91e- 0.056
0
3
10
a =1/2 = 977e- 0.225
0
6
12
a =1/2 = 244e- 0.9
0
6
14
a =1/2 = 61.0e 3.6
0
-6
- -
EP3356-0022