Rockwell Automation RECOMM-PBUS PROFIBUS Communications Module User Manual
Page 64
6-12
PROFIBUS Communications Module
Figure 6.6 – Sample SLC Ladder Logic - Main Program (Continued)
Execute LAD 4 - Station 2 Drive Logic
0006
JSR
Jump To Subroutine
SBR File Number
U:4
JSR
The PROFIBUS scanner is configured for 28 bytes (14 words) of outputs for each drive. Two drives require 48 bytes (28 words).
Station 1
Station 2
Description
M0:1.0
(N20:0)
M0:1.14
(N20:14)
Logic Command
M0:1.1
(N20:1)
M0:1.15
(N20:15)
Speed Reference
M0:1.2
(N20:2)
M0:1.16
(N20:16)
Datalink A1
M0:1.3
(N20:3)
M0:1.17
(N20:17)
Datalink A2
M0:1.4
(N20:4)
M0:1.18
(N20:18)
Datalink B1
M0:1.5
(N20:5)
M0:1.19
(N20:19)
Datalink B2
M0:1.6
(N20:6)
M0:1.20
(N20:20)
Datalink C1
M0:1.7
(N20:7)
M0:1.21
(N20:21)
Datalink C2
M0:1.8
(N20:8)
M0:1.22
(N20:22)
Datalink D1
M0:1.9
(N20:9)
M0:1.23
(N20:23)
Datalink D2
M0:1.10
(N20:10)
M0:1.24
(N20:24)
Parameter Protocol Word #1
M0:1.11
(N20:11)
M0:1.25
(N20:25)
Parameter Protocol Word #2
M0:1.12
(N20:12)
M0:1.26
(N20:26)
Parameter Protocol Word #3
M0:1.13
(N20:13)
M0:1.27
(N20:27)
Parameter Protocol Word #4
0007
COP
Copy File
Source
#N20:0
Dest
#N21:0
Length
28
COP
XMIT Data
Word 0
PROFIBUS scanners vary from manufacturer to manufacturer in how the bytes are ordered in a word. For example, some PROFIBUS
scanners operate with high & low bytes swapped (the value "1234" is represented as "3412"). The WRITE data is copied into
N21: and the bytes are reversed in the SWP instruction below so a value such as "3412" is viewed as "1234".
N21: contains the actual write data that is being sent to the PROFIBUS scanner.
0008
SWP
Swap
Source
#N21:0
Length
28
SWP
XMIT Data
Word 0