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

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.

the command has not been selected in LIST, but is active. This

could occur for the following reasons:

operation of the module is being controlled by the

ladder program

the module cannot execute the LIST function selected

the processor is in program load mode

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.