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Rockwell Automation Publication 2080-UM002N-EN-E - November 2022
Chapter 2 About Your Controller
RMC is useful when the user is developing a project by incrementally adding small changes to
the logic and immediately wants to see the effects of the changes on the machine. With RMC,
since the controller stays in remote run mode, the controller logic and machine actuators will
not have to constantly reinitialize, which can occur if the controller is switched to remote
program mode (for example, first scan bit is checked in program logic to clear outputs).
When user is editing, building, and downloading a project without using RMC, a full build of the
entire controller project is performed and also a full download of the project is performed.
During RMC an incremental build is performed and only incremental changes are downloaded
to the controller.
RMC is performed incrementally at the end of every program scan in order to prevent a large
delay in the program scan. This adds up to an additional 12 ms to the scan time. For example, if
the program scan is normally 10 ms, it may increase to 22 ms during RMC until the update is
finished. Similarly user interrupts may be delayed.
A new global variable __SYSVA_PROJ_INCOMPLETE has been added to indicate when Run Mode
Changes are being made. This can be used to notify personnel on the HMI that there are
uncommitted changes in the controller.
When you perform a Test Logic Change, the value of the variable is changed from zero to one.
After you choose to accept or undo the changes, the value of the variable is reset to zero.
IMPORTANT
Do not disconnect from the controller after performing Run Mode
Change, do a full build, and try to reconnect. Connected Components
Workbench software treats the project in the controller as different from
the project in Connected Components Workbench software, and ask to
either upload or download even though the logic is identical.
Example of the Benefits of Using RMC – 20% Reduction in Download Time
Number of
Changes
Time to Perform Conventional
Download (seconds)
Time to Test Logic and
Accept Changes (seconds)
1
36
29
5
180
130
10
360
255
Memory size of project used for comparison:
Data = 14784 bytes; Program = 2352 bytes
Note: The duration starts when the RMC button is clicked while connected to the controller and ends when the
accept is finished. For example:
1. When connected to the controller, click RMC
2. Modify program
3. Click Test Logic
4. Click Accept to finish, or click Test Logic to make another change
ATTENTION:
Use extreme caution when you use Run Mode Change. Mistakes
can injure personnel and damage equipment. Before using Run Mode Change:
• Assess how machinery will respond to the changes.
• Notify all personnel about the changes.
Bit Definitions of Global Variable – __SYSVA_PROJ_INCOMPLETE
Bit
Definition
0
Set when the Run Mode Change process starts.
Cleared once the Run Mode Change is written permanently to the controller (completion of
Accept or Undo).
This bit can be used to warn operators that a run mode change is in progress and that there are
uncommitted changes in the controller.
1
Set if an error occurred while saving the changes to flash or an integrity check failed during
Run Mode Change.
Cleared on the next successful Run Mode change.
IMPORTANT
When a Test Logic is performed, or undoing changes after the Test Logic
is completed, any active communication instructions will be aborted
while the changes are downloaded to the controller.