Installation guide

Planning and Designing RIO Cable System

890 USE 101 00 October 2006

Linear Cable Topologies

Overview There are many possible topologies that may be used for RIO networks. The most

common RIO networks use one or two coaxial trunk cables with taps that connect

via coaxial drop cables to a series of remote I/O drops. At the head-end of a trunk

cable is the PLC with an RIO processor, and at each remote drop is an RIO adapter.

These topologies are linear—they do not use any branches or loops in the cable

layouts.

Standard Single-

cable RIO Cable

Systems

A single-cable linear topology, as shown in the following illustration, is the simplest

and most commonly used RIO cable system:

Note: Because this example uses local I/O at the head, the first remote drop in the

network is I/O mapped as drop #2. If the PLC you are using does not support local

I/O—e.g., the 984A/B PLCs—then the first drop in the RIO network can be mapped

as drop #1.

Head Drop #1

RIO Drop #2

RIO Drop #4

RIO Drop #3

Last RIO Drop

Trunk Cable

Tap

Drop Cable

Drop Cable Trunk Terminator

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

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

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