Allen-Bradley 2080-LC20-20QWB User Manual page 18

Chapter 2 About Your Controller
10
RMC Memory Usage Example
Controller Memory
(for User Program + Data)
Free memory
Used memory
If not enough RMC memory is available to make more changes (for example, a
"not enough memory" error message appears during RMC build or Test Logic),
then a full download must be performed to transfer the incremental changes from
the RMC memory to standard user program and data memory.
Transferring Contents in RMC Memory to Controller Memory
The changes that you have made during RMC are stored in RMC memory and
will remain there until you perform a full download (while the controller is
disconnected).
RMC Memory Usage When Performing Full Download Example
Controller Memory
(for User Program + Data)
Free memory
New used memory
However if the controller memory does not have enough space remaining to copy
the contents of the RMC memory as shown below, the operation will fail and a
"not enough memory" error message will appear. Do not use RMC if you are near
the limits of your controller memory.
RMC Memory
(Default size = 2KB)
1st change and 2nd change and
Test Logic Test Logic
(Add logic) (Remove logic)
Free RMC memory Used RMC memory
RMC Memory
(Default size = 2KB)
Used RMC memory is copied
to controller memory
Rockwell Automation Publication 2080-UM005B-EN-E - March 2015
3rd change and
Test Logic
(Add logic)
Free RMC memory