Commissioning
EL31xx-00xx
167
Version: 5.9
Combinations of filters, FastOp mode and Synchronization mode
Other combination options of filter, FastOp mode and Synchronization mode are expressly not rec-
ommended.
Synchron mode
In synchronous operation process data are generated frame-triggered, so that a new value is available with
each PLC cycle. In the EL31xx terminals synchron mode is used automatically (filter off, no DC). The
minimum cycle times are 80 µs (EL31x1/EL31x2), and 120 µs (EL31x4) for standard IPCs.
DC operation
In DC mode the process data are requested via DC interrupt. This results in the temporal jitter between two
frames being equalized, so that the sampling time is uniform across the system. The DC mode requires
minimum cycle times of
• 100 µs (EL31x1/EL31x2)
• 150 µs (EL31x4)
• 250 µs (EL3174)
• 200 µs (EL3174-0002, EL3174-0032)
• 500 µs (EL3174-0090)
for standard IPCs. In input-based mode the sync interrupt is shifted automatically, so that the process data
are ready just before the current process data cycle.
5.6.2.6
Filter operation (FIR and IIR), index 0x80n0:06, 0x80n0:15
Filter operation (FIR and IIR), index
0x80n0:06 [
}
194]
,
0x80n0:15 [
}
194]
The EL 31xx terminals incorporate a digital filter which, depending on its settings, can adopt the
characteristics of a
F
inite
I
mpulse
R
esponse filter (an
FIR filter
), or an
I
nfinite
I
mpulse
R
esponse filter (an
IIR
filter
). The filter is deactivated by default. Please observe the following note regarding activation with index
0x8000:06 [
}
194]
.
Activation of the filter with index
0x8000:06 [
}
194]
and setting of the filter charac-
teristics via index
0x8000:15 [
}
194]
The filter frequencies are set for all channels of the EL3xxx terminals centrally via index
0x8000:15
[
}
194]
(channel 1). The corresponding indices 0x80n0:15 of the other channels have no parameter-
ization function.
FIR filter
Parameterized via the index
0x8000:15 [
}
194]
.
The filter performs a notch filter function and determines the conversion time of the terminal. The higher the
filter frequency, the faster the conversion time. A 50 Hz and a 60 Hz filter are available.
Notch filter means that the filter has zeros (notches) in the frequency response at the filter frequency and
multiples thereof, i.e. it attenuates the amplitude at these frequencies.
The FIR filter operates as a non-recursive filter.
