Siemens 6ES7953-8LG30-0AA0 Micro Memory Card – Obsolete S7-300 Spare Part

Technical Dossier

Product Details And Specifications

Siemens 6ES7953-8LG30-0AA0 Micro Memory Card – Obsolete S7-300 Spare Part

RFQ support for obsolete parts: Send the model number, required quantity and destination so DriveKNMS can confirm sourcing options before quotation.

Technical Specifications

Solving the Discontinued Hardware Crisis

The SIMATIC S7-300 platform was Siemens' dominant mid-range PLC for over two decades, installed across tens of thousands of facilities worldwide between the mid-1990s and 2010s. The 6ES7953-8LG30-0AA0 MMC is not a peripheral accessory — it is a mandatory component. Every S7-300 CPU requires a valid MMC inserted at startup to load the user program from flash memory. There is no workaround, no firmware patch, and no software bypass.

Condition & Reliability Assurance

DriveKNMS applies a structured 5-step quality process to all discontinued Siemens MMC units before dispatch:

• Step 1 – Physical Inspection: Card contacts and housing examined for corrosion, pin deformation, or physical damage from improper extraction. MMC contacts are particularly susceptible to oxidation in humid environments.
• Step 2 – Flash Memory Integrity Test: Full read/write cycle verification using compatible S7-300 CPU test bench. Cards that fail sector integrity checks are rejected.
• Step 3 – Firmware Version Verification: MMC firmware version is logged and cross-referenced against known compatible CPU firmware revisions to prevent version mismatch faults.
• Step 4 – Program Load Test: A standard test program is written to and read back from the card to confirm stable load memory operation under normal operating conditions.
• Step 5 – ESD-Safe Packaging: Units are sealed in anti-static packaging with desiccant and labeled with part number, test date, and condition grade prior to shipment.

Key Features for System Maintenance

• Drop-in replacement: The 6ES7953-8LG30-0AA0 is a direct physical and functional substitute for any failed or missing MMC in an S7-300 CPU slot. No hardware modification required.
• No reprogramming of the CPU required: The user program is stored on the MMC itself. Restoring a pre-backed-up program to a replacement card restores full CPU functionality without re-engineering the control logic.
• Avoids engineering reconstruction costs: Replacing this card preserves the existing S7-300 rack, I/O wiring, PROFIBUS network, and SCADA integration. No TIA Portal migration, no re-commissioning, no revalidation of safety functions.
• Long-term storage compatible: Flash EEPROM retains data without power. Cards stored correctly in ESD-safe, low-humidity conditions maintain data integrity for extended periods.
• Supports all standard S7-300 CPU variants: Compatible across the S7-300 CPU range that requires MMC-based load memory, including CPU 312, 313C, 314, 315-2 DP, 317-2 PN/DP, and 319-3 PN/DP.

Q: Can I transfer my existing program to a replacement MMC?
A: Yes. If you have a current backup of the user program (via STEP 7 or a memory card copy), it can be written to the replacement MMC using a standard S7-300 CPU or a Siemens PG/PC with STEP 7 software. DriveKNMS can also supply blank-tested cards if you manage your own program transfer.