Fire-Lite Alarms MS-9200 Programming, Installation, Maintenance And Operating Instruction Manual page 32

Wiring the Signaling Line Circuit
Style 4 Wiring and T-tapping
T-tapping of the SLC loop wiring is allowed for 2-wire (Style 4) configurations. The total resistance of any branch
cannot exceed 40 ohms. Measure the resistance as illustrated below. The total wire length of all combined branches
cannot exceed 10,000 feet (3,000 m).
FIGURE 2-9:
Branch B
Shield
A B B+ A+ B- A-
T
B
1 2
6
In this example: Branch A + Branch B + Branch C + Branch D + Branch E = 10,000 feet (3,000 m) or less
Style 6 Wiring
T-tapping of the SLC loop wiring is not allowed for Style 6 configuration. The total resistance of the complete wire
run cannot exceed 40 ohms and total length cannot exceed 10,000 feet (3,000 m). Measure the resistance as illus-
trated below.
FIGURE 2-10:
Loop Out
Shield
A B B+ A+ B- A-
T
B
1 2
6
DC Resistance of the Communications Loop pair
cannot exceed 40 ohms.
With power removed, disconnect Loop Out and
Return at the control panel, short the two leads of
Communications Loop Return and meter Loop Out.
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Style 4 T-tapping and Branch Resistance
Branch D
Branch C
For Each Loop:
Add the lengths of all the
Loop Out
branches on one loop. This sum
cannot exceed 10,000 feet
(3,000 m) using 12 AWG (3.25
2
mm ) twisted, shielded wire.
3 4 5 6
Style 6 Wiring Requirements
No T-tapping
Return Loop
B+ and B- = Output Loop
A+ and A- = Return Loop
3 4 5 6
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Branch E
Branch Resistance
With power removed, short the termination
point of one branch at a time and measure
the DC resistance from the beginning of the
loop to the end of that particular branch.
The total resistance from panel to each
branch end cannot exceed 40 ohms. Repeat
this procedure for all remaining branches.
Total length of the Communications Loop pair cannot exceed
10,000 feet (3,000 m) using 12 AWG (3.25 mm
Document #15668 Rev. I 04/20/98 P/N 15668:I
Communication Loop Out
Branch
2
) wire.
Communication Loop Out
Communication Loop Return
29