ABB REC 561 User Manual

Direct current measuring unit
ABB Network Partner AB
1MRK 580 154-XEN
Page 7 - 9
Version 1.0-00
* please, refer to the setting table for the explanation
5 Design and measuring principle
The design of the mA input modules follows the design of all 500-series
protection, control, and monitoring terminals that have distributed func-
tionality, where the decision levels are placed as closely as possible to the
process.
Each independent measuring module contains all necessary circuirity and
functionality for measurement of six independent measuring quantities
related to the corresponding measured direct currents.
On the accurate input shunt resistor, the direct input current (from the
measuring converter) forms a voltage drop that is in proportion to the
measured current. Later, the voltage drop is processed within one differ-
ential type of measuring channel (Fig. 4).
The measured voltage is filtered by the low-pass analogue filter before
entering the analogue to digital converter (A/D). Users can set the sam-
pling frequency of the A/D converter between 5 Hz and 255 Hz to adapt
to different application requirements as best as possible.
Table 1: Dependence of reporting on different setting parameters
EnDeadB* EnIDeadB* EnDeadBP* RepInt*
Reporting of the new value
Off Off Off 0 No measured values is reported
Off On On t>0 The new measured value is reported only if the time t period expired and if, during
this time, the integrating dead-band limits were exceeded
On Off On t>0 The new measured value is reported only if the time t period expired and if, during
this time, the amplitude dead-band limits were exceeded
On On On t>0 The new measured value is reported only if the time t period expired and if at least
one of the dead-band limits were exceeded
Off On Off 0 The new measured value is reported only when the integrated dead-band limits
are exceeded
On Off Off 0 The new measured value is reported only when the amplitude dead-band limits
were exceeded
On On Off 0 The new measured value is reported only if one of the dead-band limits was
exceeded
x x Off t>0 The new measured value is updated at least after the time t period expired. If the
dead-band supervision is additionally selected, the updating also occurs when the
corresponding dead-band limit was exceeded.

ABB REC 561 Specifications

General

Brand	ABB
Model	REC 561
Category	Touch terminals
Language	English