Rockwell Automation Logix5000 Controllers Add-on Instructions Programming Manual - Manual (Page 18)

Chapter 1 Designing Add-On Instructions
Logic routine
The logic routine of the Add-On Instruction defines the primary functionality of
the instruction. It is the code that executes whenever the instruction is called. The
following image is the interface of an Add-On Instruction and its primary logic
routine that defines what the instruction does.
18 Rockwell Automation Publication 1756-PM010F-EN-P - October 2014