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PREMIER AD INSTALLATION MANUAL.
Software:31/3/04 & LC6
11.9 LOOP WIRING FAULTS
***
FAULT
***
A loop fault can be caused by a break, or short circuit in the
Loop wiring. Open the panel and look for the 4 green LEDs on
Loop Fault Exists
the termination PCB. Under normal conditions these should be
all lit steady. The LEDs represent Loop1 Side A, Loop 1 side B,
Loop2 Side A and Loop 2 side B.
If both loop LEDs for either loop are off, then this indicates that there is a short on the loop that the
isolators couldn't bypass. (Check that the isolators are enabled, and aren't set for a cable continuity
check). Split the loop half way, and check if either side of the loop will power up. Continue making
more splits until the short has been found.
If The LEDs for a loop are flashing (both on, side a only, both on, side b only etc), then this indicated
a break in the wiring. This could be caused by either a break, or a pair of isolators shutting down a
short circuit. If there are several missing devices (wait for the zone fault LED & check the addresses
in that zone), then there is probably a short circuit on the loop (look for isolators lit Yellow or flashing).
The missing devices should give an indication of the section with the break. Investigate that section
as per the dead short circuit fault tracking method, as described above.
If there are no missing devices, then there is probably a simple break. Disconnect one side of the
loop and check which devices can be read. The break should be after the last read device.
PAGE 22
Approved Document No: GLT.MAN-105
Issue : 1.02
Authorised: GH
Date: 15/03/2004
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