Rockwell Automation 1775-MX_S4A,D17756.3.1 User Manual PLC-3 BACKUP CONC(OR.DU1 - Manual (Page 102)

Programming Techniques
Chapter 5
5-21
Figure 5.7
Sending a Message at Switchover
| B1:0 S0:3 +MSG–––––––––––––––––––––––––+
|
+––] [–––] [–––––––––––––––––––––––––––––––+MESSAGE
+–(EN)–+
| 00 17 |Control #B200:1|
|
| |Channel E2.5.1+–(DN)
|
| |#H045$N4:17=$B3:5 |
|
| | +–(ER)
|
| | |
|
| | |
|
| +––––––––––––––––––––––––––––+
|
Bit B1:0/00 is an internal storage bit used to control execution of the
transfer command. You can use any unused data table bit for this purpose. Bit
S0:3/17 is the run/backup bit.
Automatic Switchover
The following information applies if you selected Data Highway and
configured your PLC-3 backup system for automatic switchover.
At switchover,
the data highway port is disabled on the communication adapter module
in the primary processor
the station addresses of the Data Highway and modem ports on the
communication adapter module in the backup processor change to those
selected in LIST
Table 5.H lists the conditional responses that can occur with automatic
switchover.
Table 5.H
Automatic Switchover Responses
Switchover occurs and: Then:
the processor is waiting for a response the response is ignored.