Siemens AG 6ES5925-3SA11 PLC Interface Module

The Siemens 6ES5925-3SA11 CPU 925 processor module is a SIMATIC S5 central-bus CPU designed for use in the ZG 150S and 150U racks, providing the control brain for legacy automation systems. This CPU module is part of the SIMATIC S5-150U/S family and serves as the main processor to execute the control program and manage communication with attached I/O and operator interfaces. It includes a built-in 20 mA current-loop interface for connecting programming devices, operator panels, or the SINEC L1 LAN, enabling online configuration and monitoring in older installations. As an older, no longer current Siemens part, 6ES5925-3SA11 is typically sourced for retrofits, repairs, or end-of-life maintenance of S5-based lines; the data sheet notes its status as no longer active in Siemens' catalog. The model is specifically identified as CPU 925 for use in ZG 150S and 150U configurations, and is commonly found in reseller catalogs and legacy-S5 references as the CPU module for the S5 central bus, not a standalone I/O card. This part is best suited for technicians maintaining or upgrading aging S5 automation, where the CPU 925 remains compatible with ZG 150S/150U racks and the associated SIMATIC S5 hardware ecosystem.