Rockwell Automation 1757-SWKIT3200 ProcessLogix R320.0 Installation and Upgrade Guide - Manual (Page 231)

Publication 1757-IN032B-EN-P - April 2001
New Functions and Features 6-15
Support for Redundant PLC-5 Controllers on ControlNet
The Allen-Bradley Interface now supports redundant PLC-5 controllers
connected via ControlNet as shown in the following diagram:
Figure 6.6 PLC5 ControlNet Diagram
Connection Setup
Refer to the Allen-Bradley ControlNet PLC-5 Hot Backup System User
Manual (Publication 1785-6.5.24) for details on how to setup a
ControlNet PLC-5 Backup System with the 1785-CHBM ControlNet
backup cartridges.
In setting up a ControlNet PLC-5 Hot Backup System, a data table file
is created as the ControlNet Backup Configuration and Status File.
This file is created on each of the PLCs in the redundant pair and the
user specifies the file number. Word 3 in this file indicates the backup
status of the PLC (primary or backup). This file-word address must be
specified when configuring a ProcessLogix controller to support
redundant PLC’s. See the MONITOR_ADDR keyword later in this
section for details. The Allen-Bradley Interface will read the value of this
word periodically to determine if the PLC is the current primary. The
period is specified when configuring the ProcessLogix channel via the
BACKGROUND_READ keyword.
Configuring Server Hardware
Defining and configuring a ProcessLogix channel is performed using
Quick Builder. A Generic channel type is used to configure an
Server
RSLinx
PCIC
ControlNet
PLC-5 PLC-5
Redundant PLC Pair