HMI-Human Machine Interface is a user interface or dashboard that connects person to a machine, system or device. HMIs are used an operator's means to interact with PLC's RTU's and IED's. 


Common features of HMI:

A keyboard or mouse that allows the user to input information

A power supply that provides power to the system

One or more speakers that output sound

A display screen that shows information to the user


Uses:

To optimize an industrial process by centralizing or digitizing information for viewers. 

Alarms and warnings

Reliable messaging

Improved communication