Siemens 6ES7 953-8LL31-0AA0 SIMATIC S7-300 Memory Card

Siemens 6ES7953-8LL31-0AA0 is a SIMATIC S7 Micro Memory Card (MMC) designed for the S7-300 family, including C7 and ET 200 devices. It provides 2 MB of non-volatile flash memory (3.3 V NF Flash) in a compact MMC form factor, enabling storage of PLC programs and related data outside the CPU. This 2 MB MMC is used to back up, transfer, or archive project files between compatible S7-300 controllers, and can be used to load or update a program on supported CPUs via the Siemens programming tools. The card's 3.3 V flash technology is specified by Siemens for micro memory cards intended for S7-300/C7/ET 200 installations, ensuring compatibility with the S7 memory-card interface and standard MMC operation within the Siemens ecosystem. When selecting a memory card, verify that the target CPU model and firmware support the MMC size and type, as MMC compatibility can vary by device and firmware. This genuine Siemens accessory provides a removable, plug-in memory option for legacy automation setups where external memory is preferred for program management, data logging, or project portability, without modifying the controller’s internal EEPROM. The 6ES7953-8LL31-0AA0 is part of Siemens' MMC lineup for S7-300, and it is intended for use in systems that rely on accurate transfer of programs and configuration data between hardware units and during system maintenance or upgrades.