EST EST3X - Battery calculations

Appendix A: System calculations
EST3X Technical Reference Manual 241
Determining the total loop length
The total loop length is the sum of the lengths of all the wire segments installed in
the data loop.
10
12
5
1
6
(1)
(1) Signature loop controller
The total length of all the cable installed in the Signature loop cannot 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 loop 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 loop can disable the entire loop. In
order to limit the effect of a single short circuit, SIGA-IB Isolator Bases or
SIGA-IM Isolator modules can be installed at strategic points on the loop.