Rockwell Automation 1785-BCM_BEM, D17856.5.4 PLC-5 Backup Communication Module User Manual - Manual (Page 11)

Backup Concepts for the PLC-5 System
Chapter 1
1-2
A PLC-5 system configured with 1785-BCM modules provides high speed
backup communication and switchover of the Data Highway Plus and
remote I/O links. In this section we:
show a typical PLC-5 backup configuration
explain how the backup system works
describe the role of the 1785-BCM module (including 1785-BEM
module)
A Typical PLC-5 Backup Configuration
You must use BCM series B, revision C or later if you are using PLC-5/20,
-5/30, -5/40, or -5/60 processors.
A PLC-5 backup system contains two of each of the following hardware
components:
PLC-5 processor module
Processor: * Catalog Number:
PLC-5/11 series A, revision B or later 1785-L11B
PLC-5/15 series B, any revision 1785-LT series B
PLC-5/20 series A, revision B or later 1785-L20B
PLC-5/25 any revision 1785-LT2
PLC-5/30 series A, revision C or later 1785-L30B
PLC-5/40 series A, revision F or later
or series B, revision C or later
1785-L40B
PLC-5/60 series A, revision F or later
or series B, revision C or later
1785-L60B
PLC-5/80 series C, revision A or later 1785-L80B
* Contact your Allen-Bradley Sales Office or your Allen-Bradley distributor
for additional PLC-5 processors that can be configured with the
1785-BCM modules.
1785-BCM module
1785-BEM module (when applicable)
power supply
local chassis
Figure 1.1 shows a typical PLC-5 backup configuration using PLC-5/15
processors and 1785-BCM modules. Figure 1.2 shows a typical PLC-5
backup configuration using PLC-5/40 or PLC-5/60 processors, 1785-BCM
modules, and 1785-BEM modules.
Applying 1785-BCM Backup
Communication Modules to
the PLC-5 Programmable
Controller