A programmable controller (PC) is an electronic device used to control industrial processes or machines. It is a type of computer that can be programmed to perform a variety of tasks including monitoring inputs, controlling outputs and executing logical procedures.

Programmable controllers are commonly used in industrial automation, and their applications include controlling the flow of materials, temperature, pressure, and humidity. They can also be used to control machinery such as robotic arms, conveyors, and filling machines.

Programmable controllers allow users to create custom programs in order to control specific processes or machines. Programming can be done using software tools such as ladder logic, structured text, function block diagram, and sequential function chart.

Programmable controllers are designed to be highly reliable and durable in harsh industrial environments. They are typically manufactured with modular components, allowing them to be easily replaced and expanded as needed.