Rockwell Automation 1734-AENTR EtherNet/IP Network Configuration User Manual - Manual (Page 83)

Rockwell Automation Publication ENET-UM001L-EN-P - March 2014 83
Interlocking and Data Transfer between Controllers Chapter 6
Communicate with PLC-5 or
SLC Controllers 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. Remember these
considerations:
• 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.
• Messages require an INT buffer.
• Data can be moved into or out of the buffer as needed.
Converting between INTs and DINTs
If the message is to a device that uses 16-bit integers, such as a PLC-5 or SLC 500
controller, and it transfers integers (not REALs), use a buffer of INTs in the
message and DINTs throughout the project. This increases the efficiency of your
project.
1. The Message (MSG) instruction reads 16-bit integers (INTs) from the
device and stores them in a temporary array of INTs.
2. An File Arith/Logical (FAL) instruction converts the INTs to DINTs for
use by other instructions in your project.
1. An FAL instruction converts the DINTs from the Logix5000 controller to
INTs.
2. The MSG instruction writes the INTs from the temporary array to the
device.
Read 16-Bit Integers Data From
the Device Buffer of INTs DINTs For Use In
the Project
Word 1 INT_Buffer[0] DINT_Array[0]
Word 2 INT_Buffer[1] DINT_Array[1]
Word 3 INT_Buffer[2] DINT_Array[2]
Write 16-Bit Integers DINTs From the
Project Buffer of INTs Data For the
Device
DINT_Array[0] INT_Buffer[0] Word 1
DINT_Array[1] INT_Buffer[1] Word 2
DINT_Array[2] INT_Buffer[2] Word 3
1 2
1 2