Siemens 6ES5 910-0AA21 Memory Module

Siemens 6ES5 910-0AA21 Memory Submodule is a 1K EPROM memory module designed for the SIMATIC S5 PLC family, commonly used with the 110A CPU module. The part number is 6ES5 910-0AA21 (also listed as 6ES59100AA21) and it functions as an EPROM-based memory submodule that plugs into the S5 memory architecture to store the controller program and associated data. Typical catalog descriptions refer to this item as a memory submodule for the S5-110A system, delivering 1K of EPROM memory. This module is used in older Siemens S5 installations to provide persistent program storage within the processor's memory subsystem and is referenced in spare parts catalogs and repair listings as a 1K EPROM memory module. When replacing or upgrading an S5 controller, this 6ES5 910-0AA21 component fits into the established S5 memory topology to restore or maintain the non-volatile memory capacity required by the PLC's logic and data storage needs. In practice, technicians seek this part to repair legacy automation lines that rely on EPROM-based storage, and it appears across catalogs and refurbishment inventories under the 6ES5 910-0AA21 or 6ES59100AA21 designation.