Both human machine interfaces (HMI) and user interfaces (UI) are found in a vast array of real-world applications, ranging from retail checkout systems to warehouse controls and consumer entertainment. While they share some similarities, though, they are two unique interfaces with their own purpose and characteristics. So if you’re trying to grasp the concept of UIs vs HMIs, keep reading for a break down of these terms and their respective meanings.
Computers and Electronic Devices
One of the main differences between user interfaces and human machine interfaces involves their application. Granted, there are exceptions to this rule, but the term user interface is most commonly used when speaking about computers, tablets, and similar consumer-grade electronic devices. When you type words into a computer, for instance, you are seeing a user interface.
Machines and Equipment
If user interfaces are intended for use with computers and electronic devices, then what are human machine interfaces used for? As the name suggests, HMIs are intended for use with machines and equipment. You’ll often find them in factories and similar industrial settings where the HMI is used to perform various commands through user input. Normally, there’s a single HMI for each machine, meaning half a dozen different machines would have half a dozen different HMIs.
Another key difference between UIs and HMIs is the number of interfaces they contain. A UI in a computer system, for instance, may contain two or more different interfaces (used for various purposes). HMIs, however, typically only have a single interface that is not changes or rotated during its use.
The Bottom Line…
To recap, both the terms user interface and human machine interface refer to a type of digital interface through which a human operator inputs commands. The fundamental difference between the two, however, lies in their application. User interfaces are most commonly used in computers and similar electronic devices, whereas human machine interfaces are typically used in machines and commercial equipment. Hopefully, this will give you a better understanding of HMIs and UIs and their respective definitions.