Rockwell Automation RECOMM-PBUS PROFIBUS Communications Module User Manual

Page 63

Using I/O Messaging

6-11

For Ladder 3 Station 1 Drive Logic, see figure 6.5, Sample SLC
Ladder - Station 1 Program.

For Ladder 4 Station 2 Drive Logic, see figure 6.6, Sample SLC
Ladder - Station 2 Program.

Figure 6.5 – Sample SLC Ladder Logic - Main Program (Continued)

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 READ data is copied into
N10: and the bytes are reversed in the SWP instruction below so a value such as "3412" is viewed as "1234".

0003

COP

Copy File
Source

#N9:0

Dest

#N10:0

Length

COP

Station 1
Logic Status

File N10: contains the actual read data that can be used elsewhere in the ladder program.

Station 1

Station 2

Description

M1:1.0

(N10:0)

M1:1.14

(N10:14)

Logic Status

M1:1.1

(N10:1)

M1:1.15

(N10:15)

Speed Feedback

M1:1.2

(N10:2)

M1:1.16

(N10:16)

Datalink A1

M1:1.3

(N10:3)

M1:1.17

(N10:17)

Datalink A2

M1:1.4

(N10:4)

M1:1.18

(N10:18)

Datalink B1

M1:1.5

(N10:5)

M1:1.19

(N10:19)

Datalink B2

M1:1.6

(N10:6)

M1:1.20

(N10:20)

Datalink C1

M1:1.7

(N10:7)

M1:1.21

(N10:21)

Datalink C2

M1:1.8

(N10:8)

M1:1.22

(N10:22)

Datalink D1

M1:1.9

(N10:9)

M1:1.23

(N10:23)

Datalink D2

M1:1.10

(N10:10)

M1:1.24

(N10:24)

Parameter Protocol Word #1

M1:1.11

(N10:11)

M1:1.25

(N10:25)

Parameter Protocol Word #2

M1:1.12

(N10:12)

M1:1.26

(N10:26)

Parameter Protocol Word #3

M1:1.13

(N10:13)

M1:1.27

(N10:27)

Parameter Protocol Word #4

0004

SWP

Swap
Source

#N10:0

Length

SWP

Station 1
Logic Status

Execute LAD 3 - Station 1 Drive Logic

0005

JSR

Jump To Subroutine
SBR File Number

U:3

JSR