What is HMI?

The Human Machine Interface (HMI) is the interface between the processor machine and the operator. In essence, it’s an operator’s dashboard. This is the primary tool operators and line supervisors use to coordinate and control industrial and manufacturing processes and machines. HMIs translate complex process variables into usable and actionable information.

Displaying near real-time operational information is the domain of the HMI. Visual process graphics give meaning and context to the motor and valve status, tank levels, and other process parameters. HMIs give operational insight into the process and enable control and optimization by regulating production and process targets.


The purpose of the HMI is to display easily-understandable, real-time operational information. Visual process graphics give meaning and context to the motor and valve status, tank levels, pressure, vibration, and other process parameters. HMIs, bring you into the process so you can control and optimize it by regulating production and process targets. The HMI also helps managers and supervisors improve the process by providing historical and trending data on machine efficiency or product quality. The flexibility and advanced capabilities of today’s HMI software present vast new opportunities for improving machine and process efficiency.

A Human-Machine Interface (HMI) is a user interface or dashboard that connects a person to a machine, system, or device. While the term can technically be applied to any screen that allows a user to interact with a device, HMI is most commonly used in the context of an industrial process.

Although HMI is the most common term for this technology, it is sometimes referred to as Man-Machine Interface (MMI), Operator Interface Terminal (OIT), Local Operator Interface (LOI), or Operator Terminal (OT). HMI and Graphical User Interface (GUI) are similar but not synonymous: GUIs are often leveraged within HMIs for visualization capabilities.

In industrial settings, HMIs can be used to:

Visually display data
Track production time, trends, and tags
Oversee KPIs
Monitor machine inputs and outputs
And more
Similar to how you would interact with your air-conditioning system to check and control the temperature in your house, a plant-floor operator might use an HMI to check and control the temperature of an industrial water tank, or to see if a certain pump in the facility is currently running.

HMIs come in a variety of forms, from built-in screens on machines, to computer monitors, to tablets, but regardless of their format or which term you use to refer to them, their purpose is to provide insight into mechanical performance and progress.