Design And Measuring Principle - ABB REC 561 User Manual

ABB Network Partner AB
Version 1.0-00
Table 1: Dependence of reporting on different setting parameters
Off Off Off 0
Off On On t>0
On Off On t>0
On On On t>0
Off On Off 0
On Off Off 0
On On Off 0
x x Off t>0

5 Design and measuring principle

Direct current measuring unit
Reporting of the new value
No measured values is reported
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
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
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
The new measured value is reported only when the integrated dead-band limits
are exceeded
The new measured value is reported only when the amplitude dead-band limits
were exceeded
The new measured value is reported only if one of the dead-band limits was
exceeded
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.
* please, refer to the setting table for the explanation
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.
1MRK 580 154-XEN
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