Siemens SIMATIC ET 200S Manual page 128

Functions of the IM 151-7 CPU
Downloading a user program to the MMC using the PD/PC
Case A: Downloading a new user program
You have created a new user program. Download the complete program to the
MMC using the PD/PC.
Case B: Reloading blocks
You have already created a user program and downloaded it to the MMC (case A).
You can then add further blocks to the user program. To do so, you do not have to
download the complete user program to the MMC again; you only have to reload
the new blocks to the MMC (this method shortens the loading time in the case of
very complex programs!).
Case C: Overloading
In this case, you make changes to blocks of your user program. You then overload
the user program or only the modified blocks to the MMC using the PD/PC.
Warning
!
When blocks/a user program are overloaded, all of the data stored on the MMC
under the same name is lost.
When a block has been downloaded, the content in the case of process-related
blocks is transferred to the working memory and activated.
Erasing blocks
When a block is erased, it is deleted from the load memory. It is possible to erase
data blocks from the user program (SFC 23 "DEL_DB").
If memory in the working memory has been occupied by this block, this memory is
released.
Uploading
Unlike downloading, uploading involves loading individual blocks or a complete
user program from the CPU to the PD/PC. In this case, the blocks have the same
content as when last downloaded to the MMC. Process-related data blocks are the
exception; they receive the current values.
Uploading blocks or the user program from the CPU using STEP 7 does not have
any effect on the memory assignment of the CPU.
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ET 200S IM 151-7 CPU Interface Module
A5E00058783-04