Examples, Examples -6, Plc messaging – Rockwell Automation 1336-GM6 Enhanced DeviceNet Communications Module User Manual

Page 76

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7-6

Using DeviceNet Explicit Messaging

Examples

The following examples show messages used with the ladder logic
programs begun in Chapter 6, Ladder Logic Programming.

PLC Messaging

Figure 7.3, started in Chapter 6, Ladder Logic Programming, shows
an example PLC ladder logic program that sends an explicit message.
The message sent is contained in N30, beginning at word 0. The
response data will appear in N30 starting at word 70.

Figure 7.3

PLC Messaging Example

!

ATTENTION: The example ladder logic program
shown in this manual is intended solely for purpose of
example. Because there are many variables and
requirements associated with any particular installation,
Rockwell Automation does not assume responsibility or
liability (to include intellectual property liability) for
actual use based upon the example shown in this
publication.

0000

I:000

17

ONS

B3:0

0

EN

DN

ER

BTW

Block Transfer Write
Module Type 1771-SDN DeviceNet Scanner Module
Rack

000

Group

0

Module

0

Control Block

BT20:2

Data File

N30:0

Length

64

Continuous

No

BTW

MOV

Move
Source

0
0<

Dest

N30:70

257<

MOV

0001

BT20:2

DN

CMP

Comparison
Expression N30:70 <> N30:0

CMP

BT20:3

EN

EN

DN

ER

BTR

Block Transfer Read
Module Type 1771-SDN DeviceNet Scanner Module
Rack

000

Group

0

Module

0

Control Block

BT20:3

Data File

N30:70

Length

64

Continuous

No

BTR

0002

END

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