Installation guide

Planning and Designing RIO Cable System

890 USE 101 00 October 2006

The two cables are treated as two separate networks, and each cable is an

independent system running from the same RIO processor node to the same remote

I/O drops. If a break occurs in cable A or cable B, an LED goes ON at the RIO head

processor. The condition is also logged in words 179 ... 277 of the status table: these

status words can be accessed via the STAT instruction (see Modicon Ladder Logic

Block Library User Guide, 840 USE 101 00).

A redundant cable topology requires two RIO cable ports on the RIO processor and

on all the RIO drop adapters.

Dual Cable

Systems

If your RIO processor has two cable ports, then two linear cables can be run along

separate routes to different sets of remote drops. A dual cable system can be used

to extend the total length of the cable system. This topology allows you to use the

full dynamic range in both directions, thus allowing the cable system’s total length to

be extended. This topology requires a dual cable port at the RIO processor and a

single cable port at each of the RIO drop adapters.

The lengths of the trunk cables and the number of drops from each do not need to

be balanced in a dual cable system. In most respects, the two lines can be installed

as if they were two independent cable systems, with two special considerations:

z The total number of drops on both lines must not exceed the maximum number

of drops supported by the PLC

P/S PLC RIO I/O I/O I/O

P/S RIO I/O I/O I/O P/S RIO I/O I/O I/O

Trunk Cable B

Trunk Cable A

Trunk Terminator

Drop #1 on B Last Drop on B

Last Drop on A

Drop #1 on B

Tap Tap

Tap

This document provided by Barr-Thorp Electric Co., Inc. 800-473-9123 www.barr-thorp.com