A programmable logic controller, PLC for short, is a device or computer for controlling or regulating a machine or system. Automation technology consists of robots in addition to CNC controls, although the boundaries are fluid. It can be used for a wide range of tasks.
In the simplest case, a PLC has inputs, outputs, an operating system (firmware) and an interface through which a corresponding program can be loaded. The PLC is connected to the machine or plant with sensors and actuators. In addition, there are status displays. The sensors are connected to the inputs of the PLC and communicate what is happening in the machine or plant to the PLC.
Advantages of this technology are flexibility, fast function changes, lower space requirements, lower costs, possible networking with other systems as well as fault diagnosis and remote maintenance of the programs.