Technical data

Downloading and Uploading
19.5 Compressing the User Memory (RAM)
Programming with STEP 7
438 Manual, 05/2010, A5E02789666-01
19.5 Compressing the User Memory (RAM)
19.5.1 Gaps in the User Memory (RAM)
After deleting and reloading blocks, gaps can occur in the user memory (load and work memory)
and reduce the usable memory area. With the compress function, the existing blocks are
rearranged in the user memory without gaps, and a continuous free memory is created.
The following figure shows a diagram of how occupied blocks of memory are shifted together by
the compress function.
Always Try to Compress the Memory in STOP Mode
Only if you compress the memory in "STOP" mode are all the gaps closed up. In the RUN-P mode
(mode selector setting), the blocks currently being processed cannot be shifted since they are
open. The compress function does not work in the RUN mode (mode selector setting) (write
protection!).