The 6ES7954-8LL04 is a 256 MB Flash-EPROM memory card for SIMATIC S7-1200 and S7-1500 controllers. It occupies the middle ground in the S7-1x00 memory card lineup — more capacity than the high-endurance small cards, better write endurance than the multi-gigabyte large cards. For many automation applications, 256 MB hits the practical sweet spot: enough for the program, configuration, recipes, and a reasonable data log without paying for capacity you will never use.

Where does 256 MB sit in the endurance-to-capacity tradeoff?

SIMATIC S7 memory cards follow a consistent pattern: smaller cards endure more write cycles, larger cards store more data. The 256 MB card is rated for a minimum of 200,000 write/delete cycles, with data retention of up to 10 years when cumulative writes stay under approximately 20,000. Below it, the 4 MB and 12 MB cards offer 500,000 cycles. Above it, the 2 GB and 32 GB cards offer 100,000 cycles. If your application logs data continuously, consider stepping down to the 12 MB card. If write frequency is low and you simply need more space, the 2 GB card is the next step up.

Frequently Asked Questions

Is this card compatible with SINAMICS drives?

Yes. The 6ES7954-8LL04 works with SINAMICS drive systems that accept an S7-1x00 memory card for parameter storage and firmware updates.

Can I upgrade from a 4 MB card to this 256 MB card in an existing machine?

Yes. All S7-1x00 memory cards share the same physical interface and voltage. Power down the CPU, swap the cards, and reload the program. The CPU will recognize the larger capacity automatically.