IBA ibaPQU-S, Руководство пользователя

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Manual
Issue 1.5
29
8.5.2 Signal filtering
To calculate the characteristic values, DIN EN 61000-4-7 dictates an anti-aliasing filter
to suppress high-frequency interference that would corrupt the calculation of the har-
monic components. A digital anti-aliasing filter with a cut-off frequency of approx. 3 kHz
is implemented. This filter is also used for the raw values recorded with ibaPDA.
ibaPQU-S activates this anti-aliasing filter with the signals used for characteristic value
calculation or as synchronization signal. The configuration of these signals in ibaPDA is
ignored in this process.
Signals not used for characteristic value calculation are not changed and the settings in
ibaPDA are active.
The following table shows the filter effect:
Signal used
for charac-
teristic value
calculation Inputs Filter (cut-off frequency fc) Delay
Total
Yes Analog
U / I Analog filter with fc=12 ... 25 kHz and
digital filter with fc=3 kHz approx. 0.3 ms
No Analog None* 0
Analog filter with fc=12...25 kHz* 0.04 to 0.08 ms
Analog filter with fc=12...25 kHz
and digital filter with adjustable fc* Depends on fc
No Digital
None or debouncing in mode “stretch
rising/falling edge” or “stretch both
edges”*
0
Debouncing in mode “delay both
edges”*
Set debounce time in
µs
*Setting in ibaPDA
Note
A lot of analog modules allow setting the digital anti-aliasing filter in ibaPDA. The filter
is not available in connection with ibaPQU-S.
8.5.3 Automatic range switching
The ibaMS3xAI-1A/100A module has 2 measuring ranges: 1 A
nominal
(equivalent to
6.25 A
peak
) and 100 A
peak
. ibaPQU-S uses both ranges to calculate the characteristic val-
ues in this module:

When the current values range between -6.24 and +6.24 A, the 1 A
nominal
range is
used.

Once a measurement is outside the range, the 100 A range is activated. The
1 A
nominal
range is only reactivated if no measurement has been outside the range
+/- 6.24 A for a period of one second and either zero crossing occurs or another 200
ms have passed. These times are valid for 50 Hz or 60 Hz and have to be in-
creased accordingly at lower frequencies (e.g. 25 Hz means twice the time).