Rockwell Automation Logix5000 Controllers Add-on Instructions Programming Manual - Manual (Page 13)

Chapter 1
Designing Add-On Instructions
Add-On Instructions are available beginning with RSLogix 5000, version 16.
Add-On Instructions are custom instructions that you design and create.
Beginning in RSLogix 5000, version 18, high integrity and safety Add-On
Instructions are available.
With Add-On Instructions, you can create new instructions for sets of
commonly-used logic, provide a common interface to this logic, and provide
documentation for the instruction.
Add-On Instructions are intended to be used to encapsulate commonly used
functions or device control. They are not intended to be a high-level hierarchical
design tool. Programs with routines are better suited to contain code for the area
or unit levels of your application. The following table lists the benefits of using
Add-On Instructions
Reuse Code • You can use Add-On Instructions to promote consistency between projects by reusing
commonly-used control algorithms.
• If you have an algorithm that will be used multiple times in the same project or across multiple
projects, it may make sense to incorporate that code inside an Add-On Instruction to make it
modular and easier to reuse.
Provide an easier to understand interface • You can place complicated algorithms inside of an Add-On Instruction, and then provide an easier
to understand interface by making only essential parameters visible or required.
• You can reduce documentation development time through automatically generating instruction
help.
Export and import an Add-On Instruction • You can export an Add-On Instruction to an .L5X file that can then be imported into another
project. You can also copy and paste between projects.
Protect intellectual property • You can place your proprietary code inside of an Add-On Instruction, then use Source Protection
to prevent others from viewing or changing your code.
Simplify maintenance • You can simplify code maintenance because Add-On Instruction logic, monitored in the Logix
Designer application, animates with tag values relative to that specific instance of the Add-On
Instruction.
Track revisions, view change history, and confirm
instruction functionality
• You can add an instruction signature to your Add-On Instruction, which generates a unique
identifier and prevents the instruction from being edited without resulting in a change to the
signature.
Introduction
About Add-On Instructions
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