If it is necessary to detect the removal or failure of a single loudspeaker, the following is
advised:
– Do not connect more than 5 loudspeakers to the same loudspeaker line (line A or line B).
Field tests have shown that the impedance of loudspeakers and loudspeaker lines varies
with temperature and age. The limit of 5 loudspeakers is set due to this variation. In a
more stable environment, the number of loudspeakers can be higher.
– Make sure that all loudspeakers connected to the same loudspeaker line have the same
impedance.
Notice!
The impedance measurement of the Plena Voice Alarm System has an accuracy better than
2%. The system only generates a fault if the line impedance difference is greater than the
configured accuracy. Use the configuration software to configure the accuracy
Notice!
See the Configuration Software Manual for more information about the configuration
software.
Notice!
The maximum load for the internal power amplifier of the voice alarm controller is 240 W.
However, if the voice alarm controller is used in 2‑channel mode and an external 480 W
amplifier is connected to it, the maximum loudspeaker load can be 480 W at 100 V. This is
because in 2‑channel mode, the internal power amplifier of the voice alarm controller is used
for BGM only and distributes BGM at ‑3 dB, from which follows that the maximum power
output is 240 W at 70 V and that the loading caused by 100 V loudspeakers at 70 V is also
240 W. The external amplifier is used for calls only with 480 W output power and 100 V
loudspeaker line voltage.
Notice!
The voice alarm system has great flexibility, from one amplifier for all routers to one amplifier
per router, or any arrangement in between. But in a 2‑channel system, the number and type
of amplifiers for the call-channel has to be exactly mirrored for the music channel. Getting the
signal from the same routers and feeding loudspeaker signal to the same set of routers. If not,
amplifier supervision and amplifier sparing will not function properly.
Plena Connection | en 55
Bosch Security Systems B.V. Installation and Operation manual 2013.07 | V2.0 |