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2.10
V
I
IRTUAL
NPUT
The relays have 8 virtual input/outputs, these are internal binary stores. By assigning the status of data items like
starters, alarms, equations etc. to a virtual input/output, the status of these items can be used to fulfil higher levels
of functionality.
The status of various data items can be assigned to virtual inputs/outputs using the INPUT CONFIG > OUTPUT
MATRIX menu.
Virtual input/outputs can be used as inputs to various functions - including blocks, inhibits, triggers, alarms etc. -
using the INPUT CONFIG > INPUT MATRIX menu.
Virtual input/outputs can also be used as data items in equations.
The status of the virtual inputs and outputs is volatile i.e. not stored during power loss.
2.11
S
M
ELF
ONITORING
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. 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, therefore ensuring the circuit is protected for the maximum
time.
A Start-up Counter Meter is provided to display the number of start-ups the relay has performed. Once the
number of start-ups has exceeded a set number, an Alarm output can be given.
Reset of the counter can be done from the meter or via a binary input or a command.
Various types of start-up are monitored by the relay:
1. power-on starts
2. Expected starts (user initiated via comms)
3. Unexpected starts (caused by the relay watchdog)
Any combination of these can be selected for the start-up count. This is done in the MAINTENANCE MENU >
START COUNT menu using the Start Up Types setting. All the start-up types selected (ticked) will be added to
the overall start-up count.
The number of restarts before the alarm output is raised is set in the MAINTENANCE MENU>START COUNT
menu using the Start Up Count Target setting.
When the number of relay start-ups reaches the target value an output is raised, OUTPUT MATRIX>Start Up
Count Alarm, which can be programmed to any combination of binary outputs, LED's or virtual outputs.
©2014 Siemens Protection Devices Limited
/O
UTPUTS
--------------------
|Start Alarm
|Count
|Target
|
--------------------
Figure 2-5 Start-up Counter Meter
Chapter 1) 7SR17 Rho Description Of Operation
|
1|
100|
|
Page 21 of 78
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