7
ESPLXD-ET Controller
Loop Pattern
A Loop Pattern supports the greatest distance from controller to
decoders.
However the Loop Pattern requires that the 2-Wire path loop back and
return to the controller. The critical path for a Loop design is determined
by calculating the distance around the loop to the farthest decoder
and back to the controller. For both the Star and Loop designs, different
distances can be supported with larger gauge cable.
Maximum Critical Path Lengths for 2-Wire Paths
Nominal Wire
Size
Ohms per 1000’ or
Ohms per Km (per
conductor)
Max. Length For Critical Path
Star
Loop
Km
Miles
Km
Miles
2.5 mm2
7.5 Ohms/Km
3.00
1.86
12.00
7.46
14 AWG
2.58 Ohms/1000’
2.66
1.65
10.63
6.61
12 AWG
1.62 Ohms/1000’
4.23
2.63
16.93
10.52
10 AWG
1.02 Ohms/1000’
6.72
4.18
26.89
16.71
2-Wire Loop Pattern Design Decoders and Valves
Valve Boxes (Typical)
2-Wire splice at branch
take-offs allow easy
breaking of loop for
troubleshooting
Decoders
(Typical)
ESPLXD-ET Controller
Critical Path
Total cable length of
the loop’s critical path
(maximum 6.61 miles
(10.63 km) using
14 AWG cable)
Branch #2 L
oop
Main
Trunk L
oop
2-Wire
Loop
Branch #1 L
oop
ESPLXD-ET user-manual (670504-01) artwork_120716.indb 7
7/16/2012 3:48:04 PM
