Rockwell Automation 1775-MX_S4A,D17756.3.1 User Manual PLC-3 BACKUP CONC(OR.DU1 - Manual (Page 61)

Using the 1775ĆMX
Memory Communication Module
Chapter 4
4-14
Disable Program Compare Command
The DISABLE PROG COMP command lets you disable the program
comparison function. When this command is active, the memory
communication module resets the program comparison status bit.
Program Compare Limits Command
The PROG COMP LIMITS command lets you select specific sections of
the ladder program to be compared when ENABLE PROG COMP has
been selected.
This function works in conjunction with the enable program compare
function. For the command to operate properly, you must select the limit
before you select ENABLE PROG COMP.
When you select PROG COMP LIMITS, the PROG COMP LIMITS menu
appears. The menu shows the current value of limits used for the program
compare function. The first time you select this function, all limits are set
to zero. The display will show the values of limits upon subsequent use.
Legitimate values for limits range from 1 to 32,767.
PROG COMP LIMITS
0=COMP DISABLED
MAIN 00000
SUBROUTINE 00000
FAULT 00000
ENTER NEXT >
Each limit has a corresponding label comment number in the ladder
program. If you need further assistance with label comment numbers, refer
to the PLC-3 Programmable Controller Programming Manual (publication
1775-6.4.1) for detailed information.
When the enable program compare selection is active, the memory
communication module compares each section of the ladder program from
the first rung through the specified rung. As shown in LIST by 0 =
COMPARE DISABLED, if you set the limit for a particular section at
zero, the module does not compare that section. If the memory
communication module cannot find the label comment number for a
section, it will compare that entire section of the ladder program.