User manual

Rockwell Automation Publication 1769-UM011I-EN-P - February 2013 137
Appendix B
Dynamic Memory Allocation in
CompactLogix Controllers
This appendix explains the dynamic allocation of memory in CompactLogix
controllers.
Certain operations cause the controller to dynamically allocate and remove user-
available memory, affecting the space available for program logic. As these
functions become active, memory is allocated. Memory is then removed when
these functions become inactive.
Operations that dynamically allocate memory are:
• messages.
• connections to processors with RSLogix 5000 programming software.
• RSLinx tag optimization.
• trends.
• DDE/OPC topics.
Topic Page
Messages 138
RSLinx Tag Optimization 138
Trends 13 9
DDE/OPC Topics 139