Rockwell Automation RECOMM-IBUS Interbus Communications Module - Manual (Page 81)

Using Explicit Messaging (PCP Communications) 7-21
Figure 7.14 – LAD6 - PCP Write Subroutine (Continued)
N23:15 = Data word #1 to write (8-bit & 16-bit parameters, MSW of 32-bit parameters)
N23:16 = Data word #2 to write (LSW of 32-bit parameters)
N23:14 = Number of bytes to write ("1" for byte, "2" for 16-bit parameter and "4" for 32-bit parameter)
Data is contained in:
If only 1 byte is being written, it needs to be loaded into the high byte of Data word #1 (N23:15). The subroutine performs this
via the SWP instruction so the main program can work with a normal number (i.e. a "2" instead of a "0200" hex).
0004
B3:47
11
PCP Write
Routine
1-shot
COP
Copy File
Source
#N23:3
Dest #N23:14
Length 3
COP
PCP Write
Command Msg
# Bytes of Data
EQU
Equal
Source A
N23:14
2<
Source B 1
1<
EQU
PCP Write
Command Msg
# Bytes of Data
SWP
Swap
Source
#N23:15
Length 1
SWP
Copy the PCP Write Command message to the scanner for transmission on the network.
0005
B3:47
11
PCP Write
Routine
1-shot
COP
Copy File
Source
#N23:10
Dest #M0:1.0
Length 7
COP
The PCP Write Command 1-shot is used so the subroutine processes and sends the Command only once when called by the
MAIN PGM
0006 L
B3:47
11
PCP Write
Routine
1-shot
When the scanner acknowledges the PCP Write command, turn the Command word PCP Write bit OFF (originally comes from
N23:10 which was COPied to M0: above).
0007
M1:1.0
3
Status
PCP Write
U
M0:1.0
3
Command
PCP Write
When the scanner Status word indicates that a message is available, copy the message into an Interger file (N23:) for processing
and handshake with the scanner by turning the Command word Message Acknowledge bit ON.
0008
M1:1.0
15
Status
Message
Present
B3:47
12
PCP Write
Reply Msg
1-Shot
COP
Copy File
Source
#M1:1.0
Dest #N23:20
Length 5
COP
PCP Write
Reply Msg
Status Word
L
M0:1.0
15
Command
Message
Acknowledge
When the scanner acknowledges the PCP Write command, turn the Command word PCP Write bit OFF (originally
comes from N23:10 which was copied to M0: above).