Most modern control systems employ a PLC (Programmable Logic Controller) as a means to control motors, pumps, valves and various other equipment used in a process. Computer based HMI (Human Machine Interface) products provide the means by which process personnel interact with the PLC control system.

Human machine interface (HMI) software is programming that gives operators a way to manage machine command panels. Interaction is through a graphical user interface that facilitates information exchange and communication between two types of HMI — supervisory and machine level.