A human-machine interface (known as an HMI) is an industrial electronics product that’s used to interact the operation and control between humans and machines. An HMI provides feedback from the industrial machine to the end user which helps the user make changes so that the machine is more effective in production. An HMI can also provide a way to control, manage, monitor and visually operation processes during production. HMI’s are used in all sorts of production applications across the world; but are extremely popular in heavy machinery, robotics, process controls, ergonomics, PLC and other related applications.

An industrial HMI system’s processing power determines it’s usability and its ability to render complex screens. An HMI’s fast response time to user input and ﬂexibility to handle multiple levels of operator interactions is also determined upon the processing power within the HMI. HMI’s require dynamically changing graphics that require a high-performance solution that can achieve the 60 frame per second refresh rate that’s required at the right resolution. HMI’s also have to support multiple connectivity and communications protocols to communicate between the operator and various machines and control systems.

HMI’s range from simple displays to high resolution LCD panels and can be mounted on the machine, portable handheld devices, and also in centralized control cabinets. HMI’s are used in machine and process control to connect sensors, actuators and machines on the plant ﬂoor to I/O control and PLC systems. An operator control cabinet allows an HMI operator to interact with the machine in a visual way. With controls and read-outs graphically displayed on the screen, the HMI user can use either external buttons or a touch screen to control the industrial machine it’s connected to.

sources:

http://www.pcmag.com/encyclopedia/term/44300/hmi

https://en.wikipedia.org/wiki/User_interface