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2.
The max. number of loop powered ABHW-4BZ for the worst case
scenario (All detectors wired at the end of 50 ohms cable)
Detector Loaded
in one DLC
Current available
for ABHW-4BZ
Max number of loop powered ABHW-4BZ
High dBA
Low dBA
252 FD-UL detectors
189 mA
25
42
252 H-series detectors
Note
Note
Note
100 FD-UL detectors and
152 H-detectors
113 mA
15
25
Note: Loop power can’t be used for ABHW-4BZ with H-series detector
and the external power must be used.
3.
How to calculate the max. number of loop powered ABHW-4BZ.
Step 1:
Calculate the total load current (Id) for the devices loaded in the device
line using the current rating of each device including accessories.
Example: Current load of 100 FDOT421 detectors = 0.25mA*100 = 25mA
Current load of 152 HFP-11 detectors = 0.75mA*152 = 114mA
Step 2:
Find out the max. device load current (I
max
) of device line card at worst
case from the user manual of the panel.
Example: For DLC in XLS systems, 252 H-series devices can be
loaded at the end of 50 ohms max. line resistance (the worst case) and
max. load current is 252mA (I
max
).
Step 3:
Find out the available load current (I) for loop powered ABHW-4BZ
audible bases.
I = I
max
– Id
Example: If 100 FDOT421 and 150 HFP-11 detectors loaded at the
end of 50 ohms cable, I=252–139 = 113mA
Step 4:
Find out the max. alarm current rating for the loop powered ABHW-
4BZ (I
a
). Find out the max. number of the
loop powered ABHW-4BZ
using the charts above, or it is equal to (I/I
a
).
Example: If all ABHW-4BZs are set to Low volume, the max. number of
loop powered ABHW-4BZs is 25 (from Figure 10). The max. current
rating of ABHW-4BZ is 4.5mA (from electronic ratings). The max.
number of loop powered ABHW-4BZs is equal to 113mA/4.5mA=25.
If all ABHW-4BZs are set to high volume, the max. number of loop
powered ABHW-4BZs is 15 (from Figure 9). The max. current rating of
ABHW-4BZ is 7.5mA. The max. number of loop powered ABHW-4BZs
is equal to 113mA/7.5mA=15.