(1) Description of Operation 7SR224
Page 16 of 66 ©2009 Siemens Protection Devices Limited
Figure 2.9-1 Binary Output Logic
2.10 VIRTUAL INPUT/OUTPUTS
The relays have 16 virtual input/outputs, these are internal logic states. Virtual I/O is assigned in the
same way as physical Binary Inputs and Binary Outputs. Virtual I/O is mapped from within the INPUT
CONFIG > INPUT MATRIX and OUTPUT CONFIG > OUTPUT MATRIX menus.
2.11 SELF MONITORING OF THE CONTROLLER
The relay incorporates a number of self-monitoring features. Each of these features can initiate a
controlled reset recovery sequence.
Supervision includes a power supply watchdog, code execution watchdog, memory checks by
checksum and processor/ADC health checks. When all checks indicate the relay is operating correctly
the ‘Protection Healthy’ LED is illuminated.
If an internal failure is detected, a message will be displayed; also an event will be generated and
stored. The relay will reset in an attempt to rectify the failure. This will result in de-energisation of any
binary output mapped to ‘protection healthy’ and flashing of the protection healthy LED. If a successful
reset is achieved by the relay the LED and output contact will revert back to normal operational mode,
and the relay will restart.
2.11.1 Protection Healthy/Defective
When the relay has an auxiliary DC supply and it has successfully passed its self-checking procedure
then the front facia Protection Healthy LED is turned on.
A normally open contact can be mapped via the binary output matrix to provide an external protection
healthy signal.
A normally closed contact can be mapped via the binary output matrix to provide an external
protection defective signal. With the ‘Protection Healthy’ this contact is open. When the auxiliary DC
supply is not applied to the relay or a problem is detected within the relay then this output contact
closes to provide external indication.
A shorting contact in the case at positions 25-26 of the PSU module can be used to provide an
external indication when the relay is withdrawn.
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