Rockwell Automation RECOMM-IBUS Interbus Communications Module - Manual (Page 76)

7-16 Interbus Communications Module
7.4 Sample SLC Ladder - Peripheral
Communications Protocol (PCP)
PCP Read Subroutine (Explicit Messaging)
The PCP Read Subroutine is executed from the Main Program
(chapter 6) by turning on bit B3:47/0. Only one PCP Read or Write
can be performed at any one time. B3:47/0 will be turned off by the
subroutine when the reading is complete and signals that another
read (or write) cycle can take place.
Figure 7.9 – LAD5 - PCP Read Subroutine
N22:10 = PCP Command Word (Always set to "4" to cause a PCP Read: a "4" = bit 2 ON)
0000
B3:47
1
PCP Read
Routine
1-shot
MOV
Move
Source
4
4<
Dest N22:10
4<
MOV
PCP
Command
Word
N22:11 = The Communication Reference (CR) to read from. There is a unique CR for each Station.
"2" = CR 2 = Station 1.0
"3" = CR 3 = Station 2.0
0001
B3:47
1
PCP Read
Routine
1-shot
MOV
Move
Source
N22:0
2<
Dest N22:11
2<
MOV
PCP Read
Command Msg
CR