Programmable Logic Controllers (PLCs) are specialized digital computers used for automation of industrial processes. They monitor inputs from various sensors and devices, process the information based on pre-programmed instructions, and control outputs to machinery or systems. This allows for efficient management of tasks such as assembly lines, lighting systems, and other automated operations. PLCs are designed to be robust and reliable, often operating in harsh environments. They can be programmed using various languages, including Ladder Logic, which resembles electrical relay logic. Their flexibility and ease of programming make them essential in modern manufacturing and control systems.