The terms “human machine interface (HMI)” and “graphical user interface (GUI)” are often used interchangeably to describe systems that allow a human operator to control a connected machine or device. While they are similar, though, they aren’t the same. HMIs and GUIs differ in several ways. Therefore, you should familiarize yourself with the differences between HMIs and GUIs if you’re thinking about purchasing one of these control solutions.

What Is an HMI?

An HMI is a control system that allows a human operator to control a single machine or piece of equipment. In the manufacturing industry, HMIs are used extensively in machines like lathes and milling machines. Each heavy-duty manufacturing machine typically has its own HMI. Using the HMI, an operator can guide the machine to perform its respective tasks.

What Is a GUI?

A GUI, on the other hand, is a control system that allows a user to perform commands on a connected computer or electronic device through the use of icons and other digitally created visuals. A common example is a touchscreen smartphone or tablet. Touchscreen-enabled mobile devices such as these produce visuals on the screen, which the user can interact with to control the device. If a user wants to browse the internet on a tablet, for instance, he or she can tap the icon for the device’s mobile web browser. Because the interface is digitally created on a screen, it’s considered a GUI.

Differences Between HMIs and GUIs

The main difference between HMIs and GUIs lies in their method of operation. GUIs are characterized by the use of digitally created visuals that serve as the interface, whereas HMIs include all types of interfaces — assuming they are used to control a machine or piece of equipment.

Some HMIs contain or consist of a GUI. Others, however, don’t rely on digitally created visuals for the interface. A machine’s HMI may include nothing more than control knobs and buttons. Even without a screen, a human operator can control the connected machine by adjusting the HMI’s knobs and buttons.

HMIs are also used primarily in commercial sectors, such as manufacturing, whereas GUIs are used in both commercial and noncommercial sectors.

In Conclusion

To recap, an HMI is a control system that allows a human operator to control a machine or piece of equipment. In comparison, a GUI is a digitally created interface that’s used to control an electronic device.