Siemens S7-300 Handling with modules, Download of new blocks or delta downloads, Uploading blocks

Memory concept

4.2 Memory functions

Note

This function is only permitted when the CPU is in STOP mode. Load memory is cleared if the load operation could not be completed due to power loss or illegal block data.

4.2.3Handling with modules

4.2.3.1Download of new blocks or delta downloads

There are two ways to download additional user blocks or download deltas:

•Download of blocks: You already created a user program and downloaded it to the CPU via MMC. You then want to add new blocks to the user program. In this case, you do not need to reload the entire user program to the MMC. Rather, you can download only the new blocks to the MMC (this reduces download times for highly complex programs).

•Delta download: In this case, you only download the deltas in the blocks of your user program. In the next step, perform a delta download of the user program, or only of changed blocks to the MMC, using the PG/PC.

Warning

The delta download of blocks / user programs overwrites all data stored under the same name on the MMC.

The data of dynamic blocks are transferred to RAM and activated after the block is downloaded.

4.2.3.2Uploading blocks

Uploading blocks

Other than download operations, an upload operation is the transfer of specific blocks or a user program from the CPU to the PG/PC. The block content is here identical with that of the last download to the CPU. Dynamic DBs form the exception, because their actual values are transferred. An upload of blocks or of the user program from the CPU in STEP 7 does not influence CPU memory.

4-12	CPU 31xC and CPU 31x, Technical data
	Manual, Edition 08/2004, A5E00105475-05