Description

The Siemens CPU 1212C DC/DC/RLY is a flexible and compact PLC designed for mid-level automation systems requiring both precise digital control and the ability to handle diverse load types. Operating on a 24 V DC power supply, this hybrid model includes 8 digital inputs, 6 relay outputs capable of switching both AC and DC circuits, and 2 analog inputs (0–10 V). This configuration allows engineers to design systems that mix logic-level control with high-voltage or inductive load switching — all within a single device. With 75 KB of user program memory and 50 KB of data memory, the CPU 1212C DC/DC/RLY supports moderately complex control tasks such as conditional branching, event handling, counter/timer operations, and analog signal processing. It features a built-in PROFINET interface, enabling integration into industrial Ethernet networks for communication with HMIs, SCADA systems, and other PLCs. The relay outputs provide galvanic isolation, making it possible to connect devices operating at different voltage levels without additional interface hardware. Its modular design supports expansion with up to three signal boards and eight communication or signal modules, allowing customization to meet application-specific I/O requirements. The controller is particularly well-suited for applications such as automated test stations, HVAC control, conveyor systems, and industrial machinery where DC logic and AC load control coexist.