Siemens SIMEAS R-PMU Manual page 43

Sampling frequencies
The sampling frequencies of the different DAU types are shown in the table below.
Table 6-1
Nominal frequency
or
binary signals
50 Hz
60 Hz
Binary signals
Analog-to-digital converter
The analog-to-digital converter operates according to the sigma-delta principle. This method
uses a single-bit converter. A separate analog-to-digital converter is provided for each measur-
ing input to ensure that all measuring signals are processed simultaneously.
In order to avoid aliasing effects during the analog-to-digital conversion, the signal passes an
anti-aliasing filter (low-pass filter) before being digitized. This ensures that frequency compo-
nents in the signal to be sampled that exceed half of the sampling frequency will be suppressed.
Resolution
The analog measured values are sampled and converted into digital values with a resolution of
16 bit (max. 65,536 values). That means that 32,768 values and the "Null value" are possible for
each polarity. The following table contains the resolution of the A/D converter:
Table 6-2
Measured value
Voltage
Current
Process values
Digital Fault Recorder, SIMEAS R-PMU, Manual
E50417-H1076-C360-A5, Release 10.2012
Sampling rates
Sampling
frequency
9,600 Hz
11,520 Hz
2,000 Hz
A/D converter resolution
Measuring range
AC 1.5 V to AC 200 V
eff
AC 3 V to AC 400 V
eff
AC 5 mA to AC 7 A
eff
AC 7 A to AC 400 A
eff
DC ±10 V
DC ±1 V
DC ±20 mA
6.1 Measured Value Acquisition and Processing
DAU type
Analog signals: VCDAU, VDAU, CDAU
Process signals: DDAU
Analog signals: VCDAU, VDAU, CDAU
Process signals: DDAU
BDAU
Binary inputs: VCDAU, VDAU, CDAU, DDAU
A/D converter resolution
13.9 mV
eff
27 mV
eff
0.321 mA
eff
36.9 mA
eff
0.34 mV
0.033 mV
0.65 µA
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