Siemens SMP-E128-A2 Programmable Logic Controller Module

Siemens SMP-E128-A2 is a SICOMP RAM memory module for Siemens programmable logic controllers (PLCs), cataloged under order code C8451-A11-A28-1. This module includes 8 KB of SRAM and four holders designed to accept SRAM, EPROM, or EEPROM devices, delivering flexible memory expansion within the SMP-E128 family for legacy SICOMP RAM configurations. Historically used in Siemens open-architecture systems, SMP-E128-A2 components are referenced in Siemens' archival and reseller catalogs, with the C8451-A11-A28-1 part number appearing in documentation around 2008–2009. This memory module is intended for use in older SIMATIC automation setups that relied on SICOMP RAM modules and may be selected to replace a failed SMP-E128-A2 unit or to extend memory capacity in compatible equipment.