Rockwell Automation 1775-MX_S4A,D17756.3.1 User Manual PLC-3 BACKUP CONC(OR.DU1 - Manual (Page 52)

Using the 1775ĆMX
Memory Communication Module
Chapter 4
4-5
As shown in Table 4.B, a heading, which appears directly beneath the
system identification, identifies the current source of control commands for
the memory communication module.
Table 4.B
Menu Headings
This heading: Tells you that:
LIST CONTROL
operation of the memory communication module is being
controlled by selections made in LIST
PROGRAM CONTROL
operation of the memory communication module is being
controlled by message instructions in the ladder program
BACKUP
you are viewing LIST selections for the memory communication
module in the backup processor. These selections have no affect
on system operation (except for the Backup to Primary Data
Transfer function) as long as the primary processor is controlling
outputs.
Important: At switchover, the backup processor takes control of the
outputs and LIST selections in the backup processor take effect
immediately.
As shown in Table 4.C, symbols, which appear to the left of the entries on
the menu, identify the LIST selections that have been made and the current
operational status of the memory communication module.
Table 4.C
Menu Symbols
This symbol: Means that:
*
the command has been selected in LIST and is active.
L
the command has been selected in LIST and would be active if
module operation were under LIST control. LIST selections could
also be inactive if the primary processor is in program load mode.
A
the command has not been selected in LIST, but is active. This
could occur for the following reasons:
Ć operation of the module is being controlled by the
ladder program
Ć the module cannot execute the LIST function selected
Ć the processor is in program load mode
Ć the MCM OPERATION menu displayed is for the
memory communication module in the backup
processor
Note that there is an A entry for every L.