Automation uses control systems and information technologies to reduce the need for human work. A programmable logic controller (PLC) is a solid-state industrial computer used to monitor processes and devices. PLCs were developed to replace mechanical relays and are now commonly used in manufacturing. A PLC has a processor, memory, power supply, and input/output modules. Ladder logic is a commonly used programming language where logic operations between inputs determine outputs. PLCs provide benefits like reduced costs, increased reliability, and flexibility.