System Introduction; Product Overview - Bosch PRAESENSA Installation Manual

6 en | System introduction
3

System introduction

The loudspeaker line isolator system for surveillance of loudspeaker lines in combination with
PRAESENSA Public Address and Voice Alarm system. The main task of the loudspeaker line
isolator system is to keep the audio message broadcast in the emergency zone in case of a
loudspeaker line short‑circuit. This is done by means of, isolating damaged cable section away
from the healthy part of the cable.
The loudspeaker line isolator system covers completely the functionality of Voice Alarm
System in the area of loudspeaker line fault detection, according to EN54‑16 product
standard. The loudspeaker line isolator is capable of detecting and indicating not only
short‑circuit on the line, but also open line, disconnection of a loudspeaker and earth‑leakage
at any point of the loudspeaker line.
The loudspeaker line isolator system provides monitoring of loudspeaker lines and single
loudspeakers. In case of fatal failure on the loudspeaker line, the loudspeaker line isolator
reacts immediately and keeps seamless audio transmission.
Transparent to keep the full band audio quality unaffected up to 800 W constant AC‑power on
a single 1000‑meter loop.
3.1

Product overview

The Line isolator system comprises of two types of devices which play different roles in the
system:
LDB (LoopDrive Booster), with ordering number PRA-LID - is the central unit installed in the
Voice Alarm System rack, directly between the amplifier and loudspeaker line. Mounted on a
DIN‑rail LDB works as the DC‑power supply for FIMs and can also generate special service
commands to FIMs.
LDB is responsible for monitoring and reporting faults globally (per loudspeaker loop):
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2021.07.28 | V1.00 |
Loop short (entire loop)
Loop open (entire loop)
T-branch short (any T‑branch)
T-branch open (any T‑branch)
Earth leakage (amplifier input, entire loop, any T‑branch)
Installation manual
Loudspeaker line isolator system
Bosch Security Systems B.V.