Rockwell Automation 1785-CHBM ControlNet PLC-5 Hot Backup System User Manual - Manual (Page 21)

1 Publication 1785-UM024B-EN-P - January 2003
Chapter
2
Understanding the ControlNet PLC-5 Hot
Backup System Components
Chapter Objectives This chapter describes the components that make up the ControlNet
PLC-5 hot backup system.
Hardware Components
• two PLC-5 ControlNet programmable controllers (either
1785-L40C15 or 1785-L80C15, Series F, Revision A or later)
Each programmable controller must be in a separate 1771
chassis, and each chassis must have its own power supply.
Various chassis and power supplies are available; choose them
based upon standard 1771 and 1785 selection and installation
criteria.
• two 1785-CHBM/A ControlNet backup cartridges (one for each
PLC-5 programmable controller)
• two 1771 chassis (one for each PLC-5 programmable controller)
• two 1771 power supplies (one for each chassis)
You can elect to use redundant power supplies within a chassis
if you wish. We do not recommend the use of I/O within the
chassis, since provisions for backing up the local I/O are not
provided.
• one or more ControlNet I/O adapters
TIP
Though we do not recommend it, it is possible for
you to use a mixed set of programmable controllers
as a backup pair (e.g., one PLC-5/40 and one
PLC-5/80).