Siemens: Understanding the Memory Card of S7-400

How Memory Cards Work

Memory cards can be inserted into all S7-400 CPUs. They can be used as an expansion of the load memory. Depending on the type of memory card used, the user program will remain on the memory card even if the module is not powered up.

Types of memory cards

RAM card: Only for expanding the integrated load memory.

Flash card: For saving the user program (even without power), without buffering or saving on a medium external to the CPU.

Transferring objects from a project to a memory card

After inserting the memory card into the programming device or external programming device, you can transfer the following objects from the project navigation area to the memory card:

Individual blocks (multiple selections allowed)

In this case, a consistent transfer is possible because the dependencies between blocks are taken into account when selecting the blocks.

PLC

In this case, all processing-relevant objects are transferred (e.g. blocks and hardware configuration) to the memory card, similar to a download process.

To perform the transfer, move the objects by dragging and dropping or use the command "Write to memory card" in the "Project" menu and, if applicable, follow the prompts in the dialog box.

Transferring objects from the memory card to the project

Individual blocks can be transferred to the project via drag-and-drop (multiple selection is allowed). It is not possible to transfer the hardware configuration from a memory card to a project.

Downloading user programs to a memory card

With the command "Download user program to memory card" in the "Online" menu, you can save the entire user program to a Flash card. The Flash card is located in the CPU. Before downloading, any existing data on the Flash card is deleted.

The CPU must be in STOP mode.

Downloading to the flash card is only possible via these menu commands