Rockwell Automation Publication 2080-UM002N-EN-E - November 2022
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Chapter 2 About Your Controller
Uncommitted Changes
Uncommitted changes are changes made in RMC that have not been accepted or undone after
a Test Logic Change has been performed.
If the controller power loses power while there are uncommitted changes, you will not be able
to re-enter RMC upon reconnection. You can choose to re-download the project to keep the
changes, or upload if the uncommitted changes are not wanted.
If you choose to upload a project with uncommitted changes from the controller, you cannot
enter RMC until you have done a full download.
RMC Memory
Run Mode Change (RMC) memory is used to store both the logic and user variable changes
made during RMC. The default amount of memory allocated is 2 KB and can be increased up to
16 KB. However there is still a limit of 2 KB for logic and user variables changes per Test Logic.
To adjust the amount of RMC memory, the controller must be offline. After you have adjusted
the amount, you must build the project and download it to the controller.
Controller Memory Diagnostics Page in Connected Components Workbench Software
During RMC an incremental build is performed and only incremental changes are downloaded
to the controller until the RMC memory has been filled.
RMC Memory Usage Example
IMPORTANT
In a Connected Components Workbench software version 8 project, the
available user data space was reduced by 6 KB to support optimal
project settings for the new RMC feature.
If you have a project that was developed before version 8, you may need
to reduce the default “Allocated” 8 KB Temporary Variables section from
the Memory page in order to compile the project successfully.
Controller Memory
(for User P Data)
RMC Memory
(Default size = 2KB)
Used memory
Free memory
Used RMC memory
Free RMC memory
1st change and
Test Logic
(Add logic)
2nd change and
Test Logic
(Remove logic)
3rd change and
Test Logic
(Add logic)