Siemens 6ES7951-1AL00-0AA0 S7 RAM Memory Card

High-Capacity Memory Expansion for S7 Systems

This RAM memory card provides additional storage capacity for SIMATIC S7 programmable logic controllers. It stores user programs, configuration data, and system parameters securely. The Siemens 6ES7951-1AL00-0AA0 offers 256 KB of memory for expanded application functionality. It supports read and write operations for flexible program management. The card uses battery-backed technology for reliable data retention during power loss. It interfaces directly with the S7 CPU via the dedicated memory card slot.

Physical Dimensions and Construction Details

The card measures 85 mm in height, 54 mm in width, and 4 mm in depth. It weighs approximately 0.02 kg with all electronic components enclosed. The 6ES7951-1AL00-0AA0 inserts easily into the designated slot on the S7 CPU. Its compact credit-card format saves significant storage space. This lightweight design enables simple handling and installation procedures.

Interface Connectivity and Electrical Specifications

A 50-pin edge connector serves as the primary interface to the S7 CPU. The Siemens 6ES7951-1AL00-0AA0 draws its operating power from the CPU connection. It communicates with the processor via a dedicated memory bus interface. The card includes a write-protect switch for program security. LED indicators display access activity and card status conditions.

Internal Architecture and Memory Technology

The PCB contains high-speed SRAM memory chips and address decoding logic. The 6ES7951-1AL00-0AA0 uses a lithium battery for data retention during power-off periods. It stores program blocks, data blocks, and system configurations effectively. The card incorporates error detection circuitry for data integrity verification. Its memory mapping supports efficient access by the host CPU.

Parameter	Specification
Model	6ES7951-1AL00-0AA0
Type	SIMATIC S7 RAM Memory Card
Memory Size	256 KB
Memory Technology	Battery-backed SRAM
Compatible Systems	SIMATIC S7-300, S7-400
Access Mode	Read and write
Data Retention	Battery-backed (minimum 3 years)
Write Protection	Mechanical switch
Power Supply	5 V DC (from CPU)
Current Draw	≤20 mA
Dimensions (H×W×D)	85 × 54 × 4 mm
Weight	0.02 kg
Operating Temperature	0 to +60 °C
Storage Temperature	–20 to +70 °C
Interface	50-pin edge connector
Status Indication	LED access indicator

Recommended Installation and Handling Practices

Insert the Siemens 6ES7951-1AL00-0AA0 carefully into the CPU memory card slot. Ensure proper orientation of the card before applying insertion force. Set the write-protect switch to the desired position for data security. Avoid touching the gold-plated edge connector contacts during handling. Store the card in a static-safe bag when not in use. Check the battery status periodically to prevent data loss.