Bosch PRAESENSA Installation Manual page 23

Loudspeaker line isolator system
3.
Possible solution
Reset LDB and observe the following indication:
1.
2.
Bosch Security Systems B.V.
Single (or odd number) twist in loudspeaker cable polarity.
– If cabling polarity is mismatched in one place in your installation (or more but odd
number), loudspeaker line isolator will react with SHORT indication.
If LDB returns to SHORT active indication, short circuit is located on the cable section
directly connected to PRIMARY or SECONDARY.
If LDB turns to OPEN active indication, short circuit is located on the loop in the field.
You need to take further steps to locate the faulty section. Two alternative solutions are
available:
– Loopdrive Sniffer (PC application) is the easiest way to go. Use FIM tracking feature
for the best result. FIM tracking is automated procedure which allows you to find the
exact location of the short fault. Please, go to the Loopdrive Sniffer manual for
details. See www.boschsecurity.com
– Disconnect loudspeaker cable from SECONDARY output of LDB and put an audio
signal in the zone including faulty loop. Loudspeaker line isolator will feed the loop
with audio signal only from PRIMARY side. While listening to loudspeakers follow the
loop and find first area with no sound reproduction. This area is isolated from the
loop because of the fault. To find the end of isolated section, connect the
SECONARY side back to LDB and find the first area with sound reproduction.
Installation manual
Troubleshooting | en 23
2021.07.28 | V1.00 |