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

1MRS 751108-MUM
4.1.8.3.
4.1.9.
Protection Relay
Technical Reference Manual, General
PO1...3
Fig. 4.1.8.2.-1 Single-pole power outputs (PO1...3)

Signalling outputs (SO)

The signalling relay outputs (SO1 and SO2) are not heavy-duty outputs and thus
they cannot be used for controlling, for example, a circuit breaker. Available relay
contacts are Normally Open/Normally Closed type (NO/NC), see the Figure
4.1.8.3.-1 below. These outputs can be used for alarming and other signalling
purposes.
NO/NC
e.g.
SO1
Fig. 4.1.8.3.-1 Signalling output (SO)

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.
+
CB
-
REX 521
PO1connrex
NoncRex
25