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ℹ️ Additional Information
| Condition |
USED/EXCELLENT CONDITION |
|---|---|
| Manufacturer |
SIEMENS |
| Product Code |
200.208.02248 |
📦 Guarantee Terms
🗂️ Product Files
🖹 Description
SIMATIC S7, Micro Memory Card for S7-300/C7/ET 200, 3, 3V Nflash, 128 KB
PLC Micro Memory Card (MMC) – Siemens 6ES7 953-8LG31-0AA0
This is a Micro Memory Card (MMC) for PLC systems, specifically the 6ES7 953-8LG31-0AA0 manufactured by Siemens. It is a specialized industrial memory card used primarily with SIMATIC S7-300 PLCs.
What it is
The SIMATIC Micro Memory Card (MMC) is a proprietary storage device designed specifically for Siemens PLC systems. Unlike standard SD or flash memory cards, it is engineered for industrial use and integrates directly into the PLC’s operation.
In many S7-300 CPUs, this card is not optional—it is required for the PLC to function.
What it does
- Stores critical PLC data, including:
o Control program (logic)
o Hardware configuration
o Data blocks and operational data - Enables:
o Program execution directly from the card
o System startup and operation
o Storage of firmware and diagnostic information (in some cases)
This makes it a core component of the PLC system rather than just an accessory.
Key details
- Capacity: 128 KB
• Type: MMC (Micro Memory Card – Siemens proprietary format)
• Designed for SIMATIC S7-300 PLC series
• Non-volatile memory (data retained without power)
Although relatively small in size, it is optimized for deterministic and reliable industrial control applications.
How it works
- The MMC is inserted into the PLC CPU slot
• The PLC reads and executes the control program directly from the card
• Without the card, many S7-300 CPUs will not start or operate
• Engineers can load, update, or replace programs by swapping the MMC
This design simplifies maintenance and ensures consistent system behavior.
Important difference
Compared to other PLC memory cards, the MMC plays a more critical role:
| Feature | 6ES7 954 (Memory Card) | 6ES7 953 (MMC – this) |
| Type | External storage | Core system memory |
| Use | Backup / transfer | Required for operation |
| PLC series | Various | S7-300 |
Where it’s used
The MMC is widely used in:
• Industrial machines and automation systems
• Production lines and manufacturing plants
• Process control applications using S7-300 PLCs
• Systems requiring stable and deterministic operation
Advantages
- Essential for PLC operation (in many S7-300 CPUs)
• Reliable non-volatile storage
• Easy program replacement and updates
• Designed for harsh industrial environments
• Ensures consistent and secure program execution
Simple explanation
In simple terms, this is the “brain memory card” of an S7-300 PLC. It doesn’t just store the program—it allows the PLC to run. Without it, the system typically won’t operate, making it a critical component in Siemens automation systems.
