The Siemens S7-1200 has three classifications of internal storage areas

The internal storage of the S7-1200 is divided into three types: working storage, loading storage and holding storage.

Loading storage area:

Non-volatile storage area. Used to store user project files (user programs, data, and configuration).

If the memory card is not used, the TIA PORTAL software is used to download the project to the CPU built-in load storage area.

If a memory card is used, the user will download the project to the memory card by using the TIA PORTAL software, that is, the memory card is used as the loading storage area.

Note: With large capacity memory cards, you can expand the load storage area

The symbol names and comments in the project can also be downloaded to the load store, which greatly facilitates debugging and maintenance.

Working storage area:

It's a volatile storage area. The CPU copies some project content from the mount store to the working store when executing user programs. After a power failure, the contents in the working storage area are lost after a power failure and cannot be extended.

Note: With a large capacity memory card, the working storage area cannot be expanded

Retention storage area:

Store process data of a specified unit when a CPU power failure occurs, ensuring that data is not lost during a power failure