Siemens 6ES5376-1AA21 Memory Module for SIMATIC S5

Core Memory Expansion for S5 CPUs

The Siemens 6ES5376-1AA21 is a CMOS-EPROM memory submodule for the SIMATIC S5 programmable logic controller family . This module provides 32 KB (16 KWords) of non‑volatile program memory for S5 CPUs . It retains data without battery backup, protecting programs against power loss and electromagnetic interference. Consequently, it expands the memory capacity of older S5 controllers.

Compatibility and Application

This memory module is specifically designed for use with S5 CPUs that require external memory expansion. For example, the CPU 928-3Ux1 requires a memory module and can utilize this module for part of its memory capacity . It is compatible with various S5 chassis styles, including the S5-90U, S5-100U, S5-115U, S5-135U, and S5-155U, which have been the backbone of industrial automation for decades . The module installs directly into the designated memory slot on the CPU or interface module.

Technical Specifications

Engineers designed this module for reliable operation within the S5 system’s environmental specifications. Its compact form factor allows straightforward installation. The following table details its key functional and physical parameters:

Application in Legacy S5 Support

Plant engineers use this memory module to maintain and support existing SIMATIC S5-based production lines. It is especially valuable in industries like automotive, manufacturing, and utilities where S5 controllers remain in operation . The Siemens 6ES5376-1AA21 enables continued operation of proven legacy equipment without full system overhauls. Therefore, sourcing tested and functional units from specialized suppliers is crucial for lifecycle management of classic Siemens automation platforms.