Siemens 6ES5374-2AH21 SIMATIC Memory Card Module

Siemens 6ES5374-2AH21 SIMATIC Memory Card Module is a long-design RAM memory card for the SIMATIC S5 PLC family. It provides 256 KB of RAM with a 16-bit data width, delivering dedicated memory capacity to support data storage and program-related operations in legacy S5 controllers. Classified as a RAM-based memory card (long form) in the SIMATIC S5 memory-card lineup, the 6ES5374-2AH21 is intended for use with older Siemens S5 hardware and serves as a drop-in memory upgrade or replacement within compatible systems. The module's RAM-based design distinguishes it from EPROM/flash-based memory cards and aligns with the long-design form factor used by S5-era hardware. This memory card is part of Siemens' historical memory solutions for S5 PLCs, offering a compact 256 KB, 16-bit memory resource that supports the continued operation of legacy automation installations where S5 components remain in service.