Bosch PRAESENSA Installation Manual page 88

88 en | Amplifier, 600W 8-channel | PRA-AD608
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Notice!
When the amplifier is powered from one or two normal 48 V power supplies, that do not have
a lifeline interface, the power saving and audio bypass functions are not available. All other
amplifier functions are still available.
To create a lifeline connection, follow the procedure below.
1.
2019.11 | V1.00 |
The multifunction power supply provides the audio signal of the highest priority
emergency call as a balanced line level analog signal on the lifeline connector (pins 5 and
6). This signal is a backup audio signal for the connected amplifier in case its network
interface or both network links would fail. The emergency call will then be distributed to
all connected loudspeakers at maximum volume and without equalization or audio delay.
The lifeline signal goes straight to the spare amplifier channel to drive all zones in
parallel. This line is supervised by the multifunction power supply.
The multifunction power supply sends information (pin 1) to the connected amplifier
about the availability of mains power. In case mains power fails and power is provided
from the battery, this signal sets the amplifier in backup power mode to disable all
amplifier channels that are not needed to make calls with a priority above the configured
priority level for the backup power mode. When no high priority calls are being made via
this amplifier, it informs the multifunction power supply (pin 2) to switch off the 48 V
converters to minimize battery power consumption even more. The power supplies and
the amplifier channels go to snooze mode and wake up every 90 seconds briefly to
perform the required supervision actions for timely fault reporting.
The multifunction power supply provides the battery or charger voltage, in the range of
12 to 18 V, to the amplifier directly (pins 3 and 4) to supply power to the amplifier's
network interface while the 48 V power supplies are switched off.
Crimp ferrules E onto the ends of the electrical wires of cable G to provide a solid and
reliable electrical connection.
– Use a dedicated crimping tool.
Installation manual
PRAESENSA
Bosch Security Systems B.V.