Siemens 6ES5373-0AA21 is an EPROM-based memory submodule (373) for the SIMATIC S5 PLC family, offering 16 KB of non-volatile storage. It interfaces with S5 CPUs as a dedicated memory module to store the program and data used by the PLC system. This part is commonly referenced as a replacement or expansion memory submodule for older SIMATIC S5 installations, enabling continued operation with compatible hardware.
