Inversion Of Digital Inputs; Outputs - ABB REX 521 Technical Reference Manual, General

1MRS 751108-MUM
4.1.7.2.
4.1.8.
Protection Relay
Technical Reference Manual, General
t
0
Input
Filter
Filtered Input
Filter Time
Fig. 4.1.7.1.-1 Filtering of a digital input
The figure above illustrates the input filtering. At the beginning, the input signal is
at high state, the first low state is filtered and no input status change is detected. The
second low state is longer than the set filter time, thus detected as a change and
attached with the time tag t
filter time, the state is accepted and attached with the time tag t
Each digital input has a filter time parameter Input # filter
(Configuration\Digital inputs\Input filtering), where # is the
number of the input.
Table 4.1.7.1-1 Filter time parameter
Parameter Values
Input # filter 1...65535 ms
A risk for debounces and short disturbances on digital inputs grows if the input filter
time is changed to less than the default value.

Inversion of digital inputs

The status of digital inputs can be inverted with parameters accessible through the
HMI or the Relay Setting Tool (Configuration\Digital inputs\Input
inversion). When inverted, the status of a digital input is TRUE (1) when no
control voltage is applied to the terminals, and FALSE (0) when the control voltage
is applied.

Outputs

The outputs are categorized as follows:
• HSPO: High speed power output, single or double pole contact, for example for
tripping purposes
• PO: Power output, single pole contact
• SO: Signal output, NO/NC (Normally open/Normally closed) contact
For detailed information about terminal connections, refer to the terminal diagrams.
Technical data of the outputs is found in the section "Technical data" on page 44.
t
1
Filter Time
dipo_rex
.When the input signal returns to high state, after the
0
Default
5 ms
REX 521
.
1
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