Installation guide

Planning and Designing RIO Cable System
54
890 USE 101 00 October 2006
Calculating
Attenuation on a
Coaxial
Network—An
Example
Here is a sample calculation of total attenuation in a five-drop RIO cable system. The
calculation is made between the head processor and the adapter at drop 5. The
distance between the head and the last tap is 2179 ft.
This system uses RG-11 cable for the trunk; for illustration purposes, its specified
attenuation is 0.24 dB/100 ft at 1.544 MHz. Running to the adapter at drop 5 is a
Modicon AS-MBII-003 RG-6 drop cable, a 50 ft cable with an attenuation of 0.3 dB.
To calculate end-to-end attenuation on the trunk cable (TCA), multiply 0.24 dB (the
trunk attenuation per 100 ft) by 21.79:
RIO I/O I/O I/OPLCP/S
Tap
RIO I/O I/O I/OP/S
RIO I/O I/O I/OP/S
RIO I/O I/O I/OP/S
RIO I/O I/O I/OP/S
RIO I/O I/O I/OP/S
Drop 1
Drop 3
Drop 5
Drop 2
Drop 4
97-5951-000
RG-11
MA-0185-100
Tap
MA-0185-100
Tap
MA-0185-100
Tap
MA-0185-100
AS-MBII-003
RG-6
AS-MBII-003
RG-6
AS-MBII-003
RG-6
AS-MBII-003
RG-6
AS-MBII-003
RG-6
52-0422-000
Trunk Terminator
50 ft 50 ft
2179 ft
Tap
MA-0185-100
TCA 0,24B 21,79× 5,23dB==
This document provided by Barr-Thorp Electric Co., Inc. 800-473-9123 www.barr-thorp.com