The 6ES7952-1KS00 is a 16 MB Flash EPROM memory card for SIMATIC S7-400 controllers. It sits in the middle of the S7-400 FEPROM capacity range — more room than the entry-level 1 MB and 2 MB cards, more economical than the 64 MB maximum. Like all FEPROM cards in the S7-400 family, it stores the user program, hardware configuration, and data blocks in non-volatile 5V Flash. On every CPU power-up, the program is automatically copied from the card into the work memory — no battery, no manual reload, no intervention.

FEPROM or RAM — which type does your S7-400 need?

FEPROM cards like the 1KS00 are non-volatile. Remove the card, store it for years, reinsert it — the program is still there. They do not need a backup battery. The tradeoff: downloading a program to a FEPROM card requires the CPU to be in STOP mode, and you cannot modify the program online at runtime. RAM cards (6ES7952-1A series) are the inverse — they need a battery to retain data through power cycles, but they support RUN-mode downloads and online program changes. Choose FEPROM when your program is stable and you want zero battery maintenance. Choose RAM when you need to modify programs without stopping the process — particularly in PCS7 environments.

What fits in 16 MB on an S7-400?

16 MB accommodates a substantial S7-400 program — hundreds of function blocks, extensive data structures, and a moderate recipe database. Most discrete manufacturing applications fit comfortably within 16 MB. Large process automation systems with thousands of I/O points, integrated HMI data structures, or extensive recipe management may approach or exceed this limit, in which case the 32 MB (6ES7952-1KT00) or 64 MB (6ES7952-1KY00) card provides the necessary headroom. Check your compiled project size in STEP 7 before ordering.

Frequently Asked Questions

How do I download a program to this FEPROM card?

Place the CPU in STOP mode. In STEP 7, navigate to PLC → Download User Program to Memory Card. The entire program — including hardware configuration, code blocks, and data blocks — is written to the card. On the next power-up or STOP-to-RUN transition, the CPU automatically copies the program from the card into work memory.

Does the 16 MB card work in an S7-400H redundant system?

Yes. FEPROM cards are supported across the S7-400H high-availability CPU range. Each CPU in the redundant pair requires its own memory card.