Allen-Bradley controllogix 1756-L63, User Manual

Page: 312 / 435

Publication 1756-UM001E-EN-P - August 2002
19-6 Communicate with Another Controller over a DH-485 Network
Step 3: Enter a Message
A. Enter a MSG instruction and associated input instruction (s).
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B. In the MSG instruction, type a name for the message control tag
and press the
Enter key.
C. In the MSG instruction, right-click the message control tag and
select
New
tag_name.
(In older revisions of the software, the
menu option is Create
tag_name.
)
D. From the Scope list, select
name_of_controller
(controller) ,
and click OK .
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E. Enter
message.
EN.
where:
message
is the message control tag from step B.
F. If your message is to an SLC 500
™
or MicroLogix
™
controller
and
it reads or writes integers (not REALs), use a buffer of INTs
in the message.
•
ControlLogix controllers execute more efficiently and use less
memory when working with 32-bit integers (DINTs). Use the
DINT data type for integers whenever possible.
•
SLC 500 and MicroLogix controllers require 16-bit integers.
•
Use an INT buffer in the message and move the data into or
out of the buffer as required.
e
e
e
e
e
e condition
/
?
EN
DN
ER Message
Message Control
? ...
MSG
e
e
e
e
e condition
/
?
EN
DN
ER Type - Unconfigured
Message Control
message ...
MSG