Siemens S7-300 Memory areas and retentivity, CPU memory areas, Three memory areas of your CPU

Memory concept

4.1Memory areas and retentivity

4.1.1CPU memory areas

The three memory areas of your CPU:

CPU

Load memory

4

Memory of the CPU

Loading memory
	MMC
(located on the MMC)
System memory
Working memory

The load memory is located on a Micro Memory Card (MMC). The size of the load memory corresponds exactly to the size of the MMC. It is used to store code blocks, data blocks and system data (configuration, connections, module parameters, etc.). Blocks that are identified as non runtime-related are stored exclusively in load memory. You can also store all the configuration data for your project on the MMC.

Note

User programs can only be downloaded and thus the CPU can only be used if the MMC is inserted in the CPU.

CPU 31xC and CPU 31x, Technical data	4-1
Manual, Edition 08/2004, A5E00105475-05