Siemens 6es5 943-7ub21 CPU Processor Module

Siemens 6ES5 943-7UB21 CPU Processor Module is a SIMATIC S5 central processing unit (CPU) module, part of the 943B family, designed for use in the S5-115U rack system. It provides 48 KB RAM for program and data storage and features two serial communication ports for peripheral links, enabling the CPU to execute control programs and exchange data within a complete S5 control configuration. Identified by order number 6ES5 943-7UB21 and revision 6, this module is compatible with the S5-115U platform and inherits the 943B's instruction set and timing characteristics. Typical uses include legacy machine controls, retrofit projects, and automation cells where an S5-115U CPU is already in service; it can serve as the execution heart when paired with appropriate RAM, EPROM options, and I/O/interface modules. This CPU module is commonly deployed as an upgrade path for older 943 variants, delivering reliable sequencing, data handling, and serial communication within Siemens' SIMATIC S5 ecosystem.