Rockwell Automation Logix5000 Controllers Add-on Instructions Programming Manual - Manual (Page 6)

Table of Contents
Using standard and safety tags ........................................................................ 34
Data access control............................................................................................. 34
Constant values................................................................................................... 35
External Access.................................................................................................... 35
Planning your Add-On Instruction design ......................................................... 36
Intended behavior .............................................................................................. 36
Parameters ............................................................................................................ 37
Naming conventions ......................................................................................... 37
Source protection ............................................................................................... 37
Nesting - reuse instructions ............................................................................. 37
Local tags .............................................................................................................. 37
Programming languages.................................................................................... 38
Scan mode routines............................................................................................ 38
Test ........................................................................................................................ 38
Help documentation ......................................................................................... 38
Chapter 2
Creating an Add-On Instruction .......................................................................... 39
Creating a parameter................................................................................................. 40
Creating a module reference parameter ............................................................... 42
Creating local tags...................................................................................................... 44
Editing parameters and local tags........................................................................... 45
Updates to arguments following parameter edits.............................................. 46
Copying parameter or local tag default values.................................................... 47
Creating logic for the Add-On instruction......................................................... 48
Execution considerations for Add-On Instructions ................................. 49
Optimizing performance.................................................................................. 49
Defining operation in different scan modes ....................................................... 49
Enabling scan modes ................................................................................................. 50
Prescan routine ................................................................................................... 51
Postscan routine ................................................................................................. 53
EnableInFalse routine ....................................................................................... 54
Using the EnableIn and EnableOut parameters ................................................ 56
EnableIn parameter and ladder diagrams..................................................... 57
EnableIn parameter and function blocks ..................................................... 57
EnableIn parameter and structured text....................................................... 57
Changing the class of an Add-On Instruction ................................................... 57
Testing the Add-On Instruction ........................................................................... 58
Before you test..................................................................................................... 58
Testing the flow .................................................................................................. 58
Monitoring logic with data context views ................................................... 59
Defining Add-On Instructions
6 Rockwell Automation Publication 1756-PM010F-EN-P - October 2014