PLCs (programmable logic controllers) and smart relays are specialized hardware used in modern industrial automation to control and monitor various functions and operations. PLCs are industrial digital computers that handle complex manufacturing tasks like robotic devices or assembly lines. They have rugged constructions that withstand challenging industrial environments and support multiple programming languages like Structured Text, Function Block Diagram, and Ladder Logic. Smart relays combine the functionality of traditional relays with programmable logic capabilities. They are compact and user-friendly, offering numerous functions ranging from counting to logic operations, and can be programmed using simple software interfaces. Smart relays are suitable for less complex applications like building automation and basic machine control.