Rockwell Automation 1775-MX_S4A,D17756.3.1 User Manual PLC-3 BACKUP CONC(OR.DU1 - Manual (Page 57)

Using the 1775ĆMX
Memory Communication Module
Chapter 4
4-10
Data Table Transfer Command
The DATA TABLE XFER command lets you transfer all of the data table
sections except the status section (section 13), from the primary processor
to the backup processor continuously. The memory communication module
transfers all undefined sections, i.e., 14, 15, and so on, as well.
The primary processor must be in run mode or test mode for transfers to
occur. If you switch the primary processor to program mode, data table
transfer becomes inactive.
The memory communication module forces the data table in the backup
processor to be identical to the one in the primary processor. Thus,
deletions as well as creations may take place in the backup processor.
Further, if a section of the data table exists in the backup processor but not
in the primary processor, that section will be deleted in the backup
processor.
LIST commands INACTIVE, FILE TRANSFER, and DATA TABLE
XFER are mutually exclusive, i.e., only one may be used at a time.
CAUTION: To guard against damage to equipment, make sure
there is sufficient memory available in the backup processor to
accommodate the data when the memory communication
module (1775-MX) executes a data table transfer. If not enough
memory is available, the backup processor will shut down.