Siemens 6ES5373-1AA41 PLC Module

Siemens 6ES5373-1AA41 is a SIMATIC S5 memory module designed for use with older Siemens PLCs in the SIMATIC S5 family. It contains a 373 CMOS-EPROM with a 32 KB capacity, providing non-volatile storage for the user program and essential data for legacy control applications. Identified by order number 6ES5373-1AA41, this 32 KB module is part of the 6ES5373-1AA4x series, which also includes higher-capacity variants such as 6ES5373-1AA61 (64 KB) and 6ES5373-1AA81 (128 KB). Marketed as a spare part, the module is intended for maintenance, repair, or refurbishment of existing S5 installations and is suitable for use with SIMATIC S5 CPUs that rely on 373 CMOS-EPROM memory modules. In practice, EPROM-based memory modules are used to retain or restore programmable logic and data when servicing legacy lines, helping preserve operation in environments that still depend on S5 hardware.