This 64 KB Flash EPROM (FEPROM) card is the entry-level non-volatile memory card for SIMATIC S7-400 PLCs. It provides the same battery-free program retention as the larger FEPROM cards at the base capacity point — suitable for moderate-size user programs that need permanent storage on the CPU.

How does this 64 KB FEPROM card compare to the 64 KB RAM card?

Both cards expand the S7-400 load memory by 64 KB, but the storage technology differs fundamentally. This FEPROM card retains the program without a battery — the CPU reloads from the card automatically on power-up. The RAM variant (6ES7952-0AF00-0AA0) requires a backup battery to hold its contents but supports RUN-mode downloads and online program changes that FEPROM cannot. Choose FEPROM for permanent deployment; choose RAM for development and commissioning.

How do I download a program to the FEPROM card?

Use PLC → Download User Program to Memory Card in STEP 7 Simatic Manager. The CPU must be in STOP mode. The standard Download button writes only to the internal CPU RAM and does not reach the FEPROM card — this distinction is a common commissioning pitfall.

Key Specifications

Frequently Asked Questions

Does this card work with any S7-400 CPU?

Yes — all S7-400 CPUs accept the long-design memory card. The 64 KB FEPROM card is compatible across the entire S7-400 range including standard and failsafe (H) CPUs.

Can I upgrade from 64 KB to a larger FEPROM card later?

Yes — the S7-400 FEPROM card family scales from 64 KB up to 64 MB. To upgrade, download the program to the new card using the same PLC → Download User Program to Memory Card procedure. No CPU firmware change or hardware modification is needed.