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PANEL PCS · HMI

What Does HMI Mean?

HMI stands for human-machine interface: the screen, software and controls through which a person monitors and operates a machine or process. In industry, an HMI is usually a touch screen panel PC or operator panel connected to a PLC, showing live values, alarms and controls for a machine, line or plant.

01

The Short Answer

An HMI is the part of an automated system that a person actually uses. It turns the signals inside a machine into screens an operator can read, and turns the operator’s touches into commands the machine can act on. The same idea is also called an operator interface terminal (OIT) or a man-machine interface (MMI).

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    Live values Temperatures, speeds, pressures, counts and machine states.
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    Alarms Faults and warnings, with the history of when they happened.
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    Controls Start, stop, mode changes and manual moves.
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    Setpoints and recipes The values and product settings the machine runs to.
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    Trends Charts of how a value has changed over a shift or a batch.
02

Types of HMI

Industrial HMIs come in a few forms: dedicated operator panels that run a PLC maker’s own software, panel PCs that run Windows or Linux and any HMI or SCADA package, touch monitors connected to a computer in a control cabinet, web HMIs viewed in a browser, and handheld devices for mobile work.

03

HMI Examples

A touch screen on a packaging machine, the overview screen of a water treatment plant, a terminal on a forklift and a self-service kiosk are all HMIs. Our guide to choosing an industrial HMI explains how to specify the hardware for each.