Loop 'Short Circuit' test
A loop short circuit isolation test should be carried out at this stage. It is recommended that the
sounders are switched On before conducting this test. If the test is unsuccessful then after the
rectification work is complete, re-allocate the loop circuit by using the 'Power-Down' and
'Power-Up' functions followed by 'Start Detection'.
End 1 Short circuit test
¨
Place a short circuit across the loop terminals at End-1. There should be no loss of
any part of the system. The display will give a 'wiring changed' message with location
of the device at which the short was detected.
¨
Run the 'Repair' function to clear the fault indication.
End 2 and Mid loop - Short circuit test
¨
A short circuit test should then be repeated at End-2 and again at mid point of the
loop.
¨
Run the 'Repair' function to clear the fault.
Loop 'Ground Break' test
A ground break test should be carried out at this stage. A single 0V line break should not cause the
loss of any part of the system. If the test is unsuccessful then after the rectification work is
complete, re-allocate the loop circuit by using the 'Power-Down' and 'Power-Up' functions
followed by 'Start Detection'.
End 1 ground cable break test
¨
Disconnect the 0V line from End-1 of a loop circuit.
¨
The cable break may have to be sustained for up to a minute. The display will show a
wiring changed message with location of device at which the break was detected.
¨
If necessary run the 'Repair' function to clear the fault indication.
End 2 ground cable break test
¨
The ground break test should be repeated at the other end of the loop circuit, End-2
and again at mid point of the loop.
¨
If necessary run the 'Repair' function to clear the system.
4188-949 issue 3_05/10_Nano Comms inst. 31
Nano panel based system
Loop 'Short Circuit' test
TERMINALS
BOARD
PANEL
enclosure
SHORTING LINK
L1
0V
DRN
LOOP END 1
PB1
REMOVE THE 0V
LINE TO
INTRODUCE A
GROUND BREAK
TERMINALS
BOARD
PANEL
enclosure
L1
0V
DRN
LOOP END 1
PB1
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