Rockwell Automation 1785-BCM_BEM, D17856.5.4 PLC-5 Backup Communication Module User Manual - Manual (Page 24)

Chapter 3
3-1
Installing Your PLC-5 Backup System
This chapter provides an overview of an installed PLC-5 backup system
and describes procedures for installing your PLC-5 backup system
(1785-BCM series B module only). These procedures are:
determining power supply requirements
setting the I/O chassis switches
setting the module switches
installing the 1785-BCM module
connecting the PLC-5 backup system
When installing a backup system for a PLC-5/40, PLC-5/60, or PLC-5/80
processor, you may choose to use a 1785-BEM backup expansion module
to provide backup for the two additional channels of the processor. Refer
to Chapter 4 for installation procedures for the 1785-BEM backup
expansion module.
Figure 3.1 shows a typical configuration of a PLC-5 backup system. In
this system, communication between the controllers is accomplished
through the two 1785-BCM modules. All of the cable connections
between the primary and backup system require a 1770-CD (Belden 9463)
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-BCM backup communication module, 1785-BEM backup expansion
module, and power supply for the backup system. Local I/O is not
backed up.
When a coprocessor is in the same chassis (standalone mode) or directly
connected to a PLC-5 processor (direct-connect mode), place the
1785-BCM and 1785-BEM modules in any other available I/O module
group in that chassis
Important: Do not place the 1785-BCM module in the same module
group (as defined by 2-slot addressing) as the coprocessor. The
1785-BCM module can reside in an adjacent slot, but not in the same
module group (under the same chassis locking tab).
Chapter Objectives
PLC-5 Backup System
Installation Overview