Rockwell Automation 1775-MX_S4A,D17756.3.1 User Manual PLC-3 BACKUP CONC(OR.DU1 - Manual (Page 43)

Operating a Backup System
Chapter 3
3-3
Startup Procedure Method 2
1. Turn off both the primary and backup processors, if they are not
already off.
2. Turn on the primary processor.
Important: Whichever processor you turn on first is designated as the
primary processor; the other is designated as the backup processor.
3. Select program load mode in the primary processor.
4. Load the program into the primary processor.
5. Using the LIST functions in the primary processor, configure all
modules in the primary processor.
6. Turn on the backup processor.
7. Select program load mode in the backup processor.
8. Using the LIST function, perform a memory download.
Important: If the primary processor was in run mode when you executed
memory download, the backup processor will be in run mode when the
download is completed.
9. If a series A, revision C (or earlier) communication adapter module
(1775-KA) is in the backup processor, change the Data Highway
station number now. If you need additional information to complete
this step, refer to the PLC-3 Communication Adapter Module User’s
Manual (publication 1775-6.5.1).
10. Select run mode in the backup processor.
11. Select run mode in the primary processor.
Important: You can write the ladder program so the primary processor
automatically performs a memory download when it enters the run mode.
Doing this would allow you to skip step 8 in the startup procedure. The
example rungs in Figure 3.1 show how to program the download.