Rockwell Automation 1785-BCM_BEM, D17856.5.4 PLC-5 Backup Communication Module User Manual - Manual (Page 50)

Installing Your 1785-BEM Module
Chapter 4
4-7
The installation procedures for the 1785-BEM backup expansion module
are:
determining power supply requirements
setting the 1785-BEM module switches
keying the I/O chassis
inserting the module into the chassis
ATTENTION: In the backup system, switch 1 of the local I/O
chassis should be in OFF position in order to allow the
switchover when a fault is detected. In remote chassis, this
switch should be positioned at the user’s discretion.
Figure 4.4 shows a typical configuration of a PLC-5 backup system using
the 1785-BEM module. In this system, all of the cable connections
between the primary and backup system require a 1770-CD cable.
Important: Do not install I/O modules for controlling your process in
the local chassis. Only the I/O modules residing in the remote chassis will
be backed up. Local chassis are necessary for housing the processor,
1785-BEM module, 1785-BCM module, and power supply for the backup
system.
Installing the 1785-BEM
Module