Rockwell Automation 1775-MX_S4A,D17756.3.1 User Manual PLC-3 BACKUP CONC(OR.DU1 - Manual (Page 40)

Installing a Backup System
Chapter 2
2-25
To configure MX backup, do the following:
1. Insert one memory communication module in the primary processor
and one in the backup processor. A memory communication module
can occupy any slot in a PLC-3 processor chassis; however, to obtain
the best system performance in multi-chassis systems, you should
place the memory communication module in the same chassis as the
memory modules.
2. Connect the XMTG end of a 1775-CM cable to the XMTG connector
on the memory communication module in the backup processor.
3. Connect the RCVG end of this cable to the RCVG connector on the
memory communication module in the primary processor.
4. Connect the RCVG end of the other 1775-CM cable to the RCVG
connector on the memory communication module in the backup
processor.
5. Connect the XMTG end of this cable to the XMTG connector on the
memory communication module in the primary processor.
6. Connect one end of a 1775-CM interconnect cable to the backup
connector on the number one scanner module in the primary
processor.
7. Connect the other end of this cable to the backup connector on the
memory communication module in the primary processor.
8. Connect one end of the other 1775-CM interconnect cable to the
backup connector on the number one scanner module in the backup
processor.
9. Connect the other end of this cable to the backup connector on the
memory communication module in the backup processor.
10. Set the option switches on the number one scanner modules in both
the primary and backup processor for automatic switchover with
controllable switchback. See Table 2.A on page 2-9 or Table 2.B on
page 2-10.
CAUTION: To guard against damage to equipment, support
1775-CM cables so the weight of the cable does not cause stress
at the connectors. If you don’t support the cables, the wires may
break.