Rockwell Automation Logix5000 Controllers Messages Programming Manual - Manual (Page 16)

Chapter 1 Controller messages
Tag Name Type Description
UCB_Set MESSAGE Control tag for the MSG instruction.
Source_Array SINT[8] Source values for the MSG instruction, including the number of
unconnected buffers that you want.
In the Logix5000 controller, use the DINT data type for integers whenever
possible. Logix5000 controllers execute more efficiently and use less memory
when working with 32-bit integers (DINTs).
If your 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.
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]
Description
The Message (MSG) instruction reads 16-bit integers (INTs) from the device and stores them in a
temporary array of INTs.
A File Arith/Logical (FAL) instruction converts the INTs to DINTs for use by other instructions in your
project.
Convert between INTs and
DINTs
16 Rockwell Automation Publication 1756-PM012F-EN-P - October 2014