This 256 KB Flash EPROM (FEPROM) card provides non-volatile load memory expansion for SIMATIC S7-400 CPUs. Unlike RAM-based memory cards, the FEPROM retains the user program without a backup battery — data persists indefinitely through power cycles. On every power-up, the CPU automatically copies the program from the card into work memory and begins execution.

When should I choose FEPROM over RAM for the S7-400?

FEPROM cards are the standard choice for final deployment where the program is stable and battery-free operation is required. They are not suited for development environments — FEPROM does not support online block modification, CFC online monitoring, or RUN-mode program downloads. For commissioning and PCS7 projects that require these features, choose a RAM card (e.g. 6ES7952-0AF00-0AA0 for 64 KB).

How do I download a program to the FEPROM card?

Use PLC → Download User Program to Memory Card in STEP 7 Simatic Manager. The standard Download button writes only to the internal CPU RAM — it does not reach the FEPROM card. The CPU must be in STOP mode for the memory card download to execute. After the download, the program is permanently stored and survives power loss without any battery.

Key Specifications

Frequently Asked Questions

Does the FEPROM card need a backup battery?

No — the user program stored on a FEPROM card is retained without any battery. However, if your application uses retentive data (bit memories, timers, counters, variable data blocks), the CPU itself still requires a backup battery to preserve those runtime values through power cycles.

Can I use this card with any S7-400 CPU?

Yes — all S7-400 CPUs support the long-design Flash EPROM memory cards. The card fits the standard memory card slot on every S7-400 CPU module. If you are migrating from an older or smaller card, no hardware or firmware changes are needed.