Signalling Outputs (So); Testing Inputs And Outputs - ABB REX 521 Technical Reference Manual, General

REX 521
4.1.8.3.
4.1.9.
18
Protection Relay
Technical Reference Manual, General

Signalling outputs (SO)

The signalling relay outputs (SO1 and SO2) are not heavy-duty outputs and thus
they cannot be used for controlling e.g. a circuit breaker. Available relay contacts
are Normally Open/Normally Closed type (NO/NC), see the figure below. These
outputs can be used for alarming and other signalling purposes.
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Testing inputs and outputs

The digital inputs and the output relays may be tested using the serial
communication or the HMI.
Generally, the relay has to be in the test mode before the inputs and outputs can be
activated. However, output relays may be activated through the serial
communication without entering the test mode. This is to enable the usage of output
relays for external purposes, not part of the protection and control in the host relay.
The test mode can be set with a parameter. The green READY LED indicator will
be blinking, to announce that the test mode has been entered. In this state, the relay
configuration is disconnected from the physical inputs so that changes on the digital
inputs will not be noticed. When the test mode is deactivated, all test parameters
requiring the test mode, will be reset.
The IRF relay may be tested by using the HMI. The IRF relay testing always requires
entering the test mode.
When testing the general output relays, the user should notice, that normal operation
of the relay cannot be disconnected. If an output relay is permanently activated by
the configuration, it cannot be deactivated for testing.
For further information, refer to Operator's manual (see "References" on page 43).
Table 4.1.9-1 Testing of inputs and outputs
Test object Using
Digital inputs HMI
Serial communication
Output relays HMI
Serial communication
IRF relay HMI
Serial communication
Requires
Remarks
test mode?
Yes Physical inputs disconnected
Yes
Yes Normal operation still active
No
Yes
Yes
1MRS 751108-MUM