Siemens 6ES5928-3UB12 Control Panel

Siemens 6ES5928-3UB12 is a SIMATIC S5 CPU 928B central processing unit designed for the S5-135U and S5-155U rack controllers. This CPU module (order number 6ES5928-3UB12) provides the processing core for legacy PLC programs and accepts RAM submodules or EPROM submodules in two memory slots to store the program and data. The 928B delivers a memory footprint of about 46 KB and offers one serial TTY port and one IFM interface for basic programming downloads and peripheral communications. Front-panel operation is indicated by four status LEDs that show run, stop, and fault conditions to assist in field troubleshooting. As a component of the older SIMATIC S5 family, the 6ES5928-3UB12 is commonly encountered in refurbish-and-retrofit projects and in installations that still rely on S5-135U/-155U control architectures for tasks such as machine control, packaging lines, and batch processes. Verified supplier listings and datasheets confirm the model, its CPU role, and compatibility within the S5-135U/155U ecosystem, making it a specific, project-ready option for upgrading or maintaining legacy Siemens automation setups.