Rockwell Automation Logix5000 Logix5000 Controllers Quick Start - Manual (Page 38)

38 Publication 1756-QS001E-EN-P - October 2009
Chapter 2 Organize a Project
Create Additional Programs
A Logix5000 controller lets you divide your application into multiple programs, each with its own tags (data).
There is no need to manage conflicting tag names between the programs.
All programs have access to data that is at the controller scope. Data at the program scope is isolated from
other programs.
• Routines cannot access data that is at the program scope of another program.
• You can re-use the tag name of a program-scoped tag in multiple programs.
• For example, both Program_A and Program_B can have a program tag named Tag_4.
Item Description
A Tag stores data. There is no fixed data table or numeric format for data addresses. The tag
name is the address (no cross-reference to a physical address). You create the tags that you
want to use.
B Program isolates logic and data from other logic and data. Each program contains one or
more logic routines as associated data.
C Scope defines whether a tag is accessible to all programs (controller tag) or limited to a
specific program (program tag). Data at the program scope is isolated from other programs.
A
B
C
Controller Tags (Global Data)
Program_A
Other routines
Main Routine Tag_4
Tag_5
Tag_6
Program Tags
(Local Data)
Tag_1
Tag_2
Tag_3
Program_B
Other Routines
Main Routine
Tag_4
Tag_5
Tag_6
Program Tags
(Local Data)
Data