Technical data

30
1MRS751108-MUM
Protection Relay
Technical Reference Manual, General
REX 521
5.1.8.3. 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 Fig. 5.1.8.3.-
1 below. These outputs can be used for alarming and other signalling purposes.
A051905
Fig. 5.1.8.3.-1 Signalling output (SO)
5.1.9. 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, see Operator’s manual (see “Related documents” on
page 10).
NO/NC
e.g.
SO1