Rockwell Automation Publication 1769-UM011H-EN-P - April 2012 139
Dynamic Memory Allocation in CompactLogix Controllers Appendix B
DDE/OPC Topics
A DDE/OPC topic uses connections based on these variables:
• Maximum number of messaging connections per controller configured in
RSLinx
• Number of connections needed to optimize throughput
• Configuration of RSLinx to use connections for writing to a ControlLogix
controller
Specify Connections per Controller
To specify the maximum messaging connections per controller, perform this
procedure.
1. In RSLinx programming software, from the Communication pull-down
menu, choose Configure CIP Options.
These variables are per path. For example, if you set up two different DDE/
OPC topics, with different paths to the same controller, the variables limit
the connections for each path. Therefore, if you have a limit of 5
connections, it is possible to have 10 connections, with 5 over each path.
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