System calculations
B.10 EST3 Installation and Service Manual
Determining the total loop length
The total loop length is the sum of the lengths of all the wire
segments installed in the data circuit.
Signature
Controller Module
10
6
12
5
1
[WIRECALC3.CDR]
The total length of all the cable installed in the Signature data
circuit can not exceed the values listed below:
Wire Size
Wire type 14 AWG 16 AWG 18 AWG
Twisted pair 13,157 ft
(4,010 m)
13,888 ft
(4,233 m)
20,000 ft
(6,096 m)
Twisted-shielded
pair
5,952 ft
(1,814 m)
6,098 ft
(1,859 m)
8,621 ft
(2,628 m)
Non-twisted,
non-shielded pair
20,000 ft
(6,096 m)
20,000 ft
(6,096 m)
20,000 ft
(6,096 m)
If the cable manufacturer’s data indicates the capacitance per
foot of the cable, the following method may be used to determine
the maximum total loop length.
Note: In no case may the total loop length of a Signature data
circuit exceed 20,000 feet (6,098 meters).
Lmax = 500,000 / Cpf
where:
• Lmax = maximum total cable length in feet
• Cpf = Cable capacitance in picofarads per foot
Note: A short circuit on a Signature data circuit can disable the
entire circuit. In order to limit the effect of a single short circuit
on the SDC, SIGA-IB Isolator Bases or SIGA-IM Isolator
modules can be installed at strategic points in the circuit.
To Next Page
Loading...