Xtralis VESDA - 4 System Configuration and Setting Thresholds; 4.1 Generic Configuration (VLC, VLS, VLP)

VESDA Accessories Guide
VESDA by Xtralis
3.3.4 Power Source
The power terminals on the remote termination card connect to a 24 VDC power supply. The four power
terminals enable power to be brought to the remote termination card via a single wire pair and looped out to
another device via another wire pair. The modules have reverse polarity protection to minimize the risk of
reverse power connection to the modules. The modules will not operate when the supply is reversed.
Note: Operating a module when DC supply voltage is outside the voltage range of 18 VDC and 30 VDC may
cause damage to the device.
Power Terminal
7
8
+24V
GND
From24V
Power
Supply
Power+
Power-
Power+
Power-
24VPowerto
NextDevice
+24V
GND
9
10
Figure 3-9: Power Connection for a Remote Termination Card
All connectors are polarized and can only be inserted one way into a socket.
Do not attempt to force a connector into its socket. If there is any difficulty, reverse the orientation of the
connector before inserting again.
3.3.5 Backup Battery
The power supply for each detector can switch to a back up battery in the event of a mains power supply
disruption. The size of the back up battery is determined by local standards and codes, the total power
required by the system, back up time required, allowance for reduction in capacity with age and expected
temperature variations.
If an intelligent VESDA power supply is fitted it will report power failures (F15) on VESDAnet. VESDA VLP &
VESDA VLS with GPI terminals connected will maintain their aspirator speed for an hour after the loss of
mains power. After which, the aspirator speed will be limited to 3000 rpm to conserve power.
See the detector product guides for information on how to calculate the size of battery backup required.
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