Rockwell Automation 1775-MX_S4A,D17756.3.1 User Manual PLC-3 BACKUP CONC(OR.DU1 - Manual (Page 104)

Programming Techniques
Chapter 5
5-23
for the primary and backup processors. Then, place executable instructions
above the rung and disallowed instructions below the rung.
Figure 5.8
Example for Disallowed Instructions
| S0:3
|
+––]/[–––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––(END)–
+
| 17
|
10987ĆI
Alternatives to the END instruction in this rung are to condition all
disallowed instructions with an examine on of bit S0:3/17, or to use a JMP
instruction conditioned by an examine on of bit S0:3/17 to branch around
groups of disallowed instructions.
If transferring the entire data table, the instructions BSL, BSR, DDT, and
FBC must not be examined in the backup processor even if rung
conditioned with the run/backup bit. You must either jump around these
instructions or put them after the END statement.
For further information about programming, see the PLC-3 Family
Programmable Controller Programming Reference Manual (publication
1775-6.4.1).
Allowed Instructions
Disallowed Instructions