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Rockwell Automation 1786-RG6F INSTL.INSTR CONTROLNET H-FLEX User Manual

Page 5

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ControlNet Standard and High-flex Coax Cable 5

Publication 1786-IN009B-EN-P - November 2003

You can increase the total trunk-cable length or number of taps by installing repeaters on the
segment. This creates another segment. The following examples explain how you can
calculate allowable lengths of segments for standard RG-6 (1786-RG6/A), and high flex
RG-6 (1786-RG6F/A) cable, as well as for a system that combines the two types of cables.

EXAMPLE

Example 1: Using only standard RG-6 cable in your system
In this example, the segment:

has 3 nodes (requires 3 taps)

uses standard 1786-RG6 cable

To calculate the allowable cable length of standard 1786-RG6/A cable:

3280 ft - (53.4 ft * [3 - 2]) = maximum length

3280 ft - 53.4 ft = 3226.6 ft (983.4 m)

EXAMPLE

Example 2: Using only RG-6F cable in your system
In this example, the segment:

has 16 nodes (requires 16 taps)

uses high-flex 1786-RG6F cable

To calculate the maximum allowable cable length of high-flex RG-6 cable
(1786-RG6F):
([20.29 dB - 16 *.32 dB] / 13.5 dB) * 1000 = 1123 ft (342.3 m)

20162-M

2570.4 ft (783.4 m)

656.2 ft (200 m)

terminator

terminator

1786-RG6 cable

tap

tap

tap

20162-M

1123 ft (342.3 m)

terminator

terminator

1786-RG6F cable

tap

tap

tap