Description: 6ES7953-8LJ20-0AA0
The Siemens 6ES7953-8LJ20-0AA0 is a **512 KB Micro Memory Card (MMC)** required for the operation of SIMATIC S7-300 CPUs (Compact and Modular types), C7 devices, and ET 200 interface modules with CPU functionality. Without this card, newer S7-300 CPUs cannot operate.
Usage & Data Retention
The MMC stores the user program, data blocks, and system configuration. It utilizes Flash EPROM technology, meaning it retains data even without a backup battery (Zero Maintenance). This 512 KB version is the sweet spot for medium-sized automation programs.
Important Handling Notes
- Formatting: Do NOT format this card in a standard Windows PC card reader, as this will destroy the Siemens-specific formatting, rendering the card useless. Only format inside the CPU or using a dedicated USB Prommer.
- Insertion: Insert only when the CPU is in STOP mode or powered off to avoid data corruption.
Compatibility
Compatible with S7-300 CPUs (e.g., CPU 312, 314, 315-2DP, 317) and IM 151-8 PN/DP CPU.
