The 6ES7952-1KL00 is a 2 MB Flash EPROM memory card for SIMATIC S7-400 controllers. It provides non-volatile 5V Flash EPROM storage for compact, focused automation programs — machines that run a single, well-defined control task with a stable code base. Like all FEPROM cards, it requires no backup battery and automatically loads the program into the CPU work memory on every power-up.

What kind of program fits in 2 MB?

A lean S7-400 program with core function blocks, essential data structures, and hardware configuration fits comfortably within 2 MB. Think of a packaging machine, a conveyor control system, a pump station, or a simple batching process — applications where the control logic is well-understood, the program has been stable across multiple machine generations, and there is no need for extensive recipe databases or integrated HMI data. If your STEP 7 project has been running unchanged for years and occupies under 2 MB, this card is the simplest, lowest-cost path to non-volatile program storage.

FEPROM or RAM at the 2 MB level — does the decision change?

The FEPROM-vs-RAM decision is independent of capacity — it depends entirely on how you manage the program. At 2 MB, a RAM card (6ES7952-1AL00) gives you the same 2 MB but with RUN-mode download capability and CFC online monitoring — at the cost of requiring a backup battery. The FEPROM card eliminates the battery but requires STOP-mode downloads. The capacity is identical; the workflow is what differs.

Frequently Asked Questions

Can I use this 2 MB FEPROM card as a temporary program transfer medium?

Yes. Write the program to the card from one CPU or programming device, then insert it into another S7-400 CPU. On power-up, the target CPU detects the program and copies it to work memory. This is a standard workflow for duplicating a program across multiple identical machines.

What happens if my program grows beyond 2 MB?

STEP 7 will report that the download target does not have enough space. You would need to upgrade to a larger FEPROM card — the 4 MB (6ES7952-1KM00), 8 MB (6ES7952-1KP00), or higher. The card's memory is fixed; it cannot be expanded.