Rockwell Automation Logix5000 Controllers Controller Information and Status Programming Manual - Manual (Page 19)

Determine controller memory information Chapter 2
When you are online with a controller, the Memory tab shows the actual memory
usage of the controller. While the controller is running, it uses additional memory
for communication. The amount of memory the controller needs varies
depending on the state of the communication.
The Memory tab of the controller includes a Max Used entry for each type of
memory. The Max Used values show the peak of memory usage as communication
occurs.
Use the following steps to reset memory usage.
1. Start the Logix Designer application and open a controller project.
2. On the Online toolbar (above the Controller Organizer), click the
Controller Properties icon.
3. On the Controller Properties dialog box, click the Memory tab.
4. Click Reset All Max to reset values.
5. Click OK.
View run-time memory
information
Rockwell Automation Publication 1756-PM015F-EN-P – October 2014 19