139
A/D module (ADM)
Chapter 10
Hardware modules
2
A/D module (ADM)
2.1
Design
The inputs of the A/D-conversion module (ADM) are fed with voltage and current signals from
the transformer module. The current signals are adapted to the electronic voltage level with
shunts. To gain dynamic range for the current inputs, two shunts with separate A/D channels are
used for each input current. By that a 16-bit dynamic range is obtained with a 12 bits A/D con-
verter.
The input signals passes an anti aliasing filter with a cut-off frequency of 500 Hz.
Each input signal (5 voltages and 5 currents) is sampled with a sampling frequency of 2 kHz.
The A/D-converted signals are low-pass filtered with a cut-off frequency of 250 Hz and
down-sampled to 1 kHz in a digital signal processor (DSP) before transmitted to the main pro-
cessing module.
Summary of Contents for REL 551-C1*2.5
Page 1: ...Technical reference manual ProtectIT Line differential protection terminal REL 551 C1 2 5 ...
Page 23: ...14 Introduction to the technical reference manual Chapter 1 Introduction ...
Page 39: ...30 Technical data Chapter 2 General ...
Page 63: ...54 Blocking of signals during test BST Chapter 3 Common functions ...
Page 71: ...62 Line differential protection phase segregated DIFL Chapter 4 Line differential protection ...
Page 89: ...80 Thermal phase overload protection THOL Chapter 5 Current ...
Page 101: ...92 Event function EV Chapter 7 Logic ...
Page 163: ...154 Terminal diagrams Chapter 11 Diagrams Figure 39 REL 551 C1 with DC switch ...
