Allen-Bradley 1756-CNB/E, User Manual

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Publication 1756-UM523F-EN-P - December 2006
78 Configure and Program the Controller
4. If you have already created individual
tags, change them to aliases.
If you have already created individual tags, change them to aliases for elements of an
array. Your logic points to the aliases. The controller crossloads the base array.
5. Keep user-defined data types as compact
as possible.
Put like data types together when you lay out a user-defined data type.
•
Put all the BOOLs together.
•
Put all the SINTs together.
•
Put all the INTs together.
Action Details
A. Create an array.
B. Change each individual tag to an alias for an element in the array.
C. Keep pointing your logic to the
individual tag names.
This is better
This data type takes 12 bytes. The BOOLs are together.
Than this
This data type takes 20 bytes. The BOOLs are spread out.