User manual

Publication CNET-UM001C-EN-P - November 2005
6-12 Peer-to-Peer Messaging
Communicate with PLC-5 or
SLC 500 Processors
If the message is to a PLC-5 or SLC 500 processor and it reads or writes
integers (not REALs), use a buffer of INTs in the message.
• Logix5000 controllers execute more efficiently and use less memory
when working with 32-bit integers (DINTs).
• PLC-5 and SLC 500 processors require 16-bit integers.
• Use an INT buffer in the message and move the data to or from DINTs
as needed. Use the DINTs in the rest of the program; this can decrease
the program scan.
Initiate MSGs from PLC-5 Processors to Logix5000 Controllers
If the originating controller is a PLC-5 processor, in the MSG instruction,
select PLC5.
The figure Configure the Message shows how to configure the message above.
IMPORTANT
Logix5000 controllers can only send messages to SLC 500
processors over ControlNet if the SLC processor uses a
KFC ControlNet communication card.
However, an SLC cannot send messages to Logix5000
controllers over ControlNet at all.