The terms “user interface” and “human machine interface” are often used interchangeably, with many people assuming they refer to the same thing: an interface through which a human controls a device or machine. While they share some similarities in terms of design and function, they are two unique systems with their own respective purpose. So if you’re struggling to grasp the concept of human machine interface (HMI) versus user interface (UI), keep reading for a breakdown on these two terms and their meanings.
When speaking about user interfaces, they are typically used in computer systems and electronic devices. According to Wikipedia, a user interface is the method for linking hardware and/or equipment with a host control system. These systems may exposure several user interfaces based on its design and function. A computerized library database, for instance, may have an interface for the library patrols (e.g. an interface with a limited set of functions to find books), as well as a separate interface specifically for the library personnel (e.g. allows for greater customization and flexibility, more so than just a search and find function).
In comparison, a human machine interface is typically restricted to a single machine or piece of equipment. So while user interfaces are linked to multiple computers or devices, a human machine interface is linked to a single machine or piece of equipment. With that said, some user interfaces of cars and industrial systems are referred to as human machine interfaces.
Hopefully, this will give you a better understanding of the differences between user interfaces and human machine interfaces. The bottom line is that both terms are used to describe an interface through which a human controls something. For human machine interfaces, the thing being controlled is typically a single machine or piece of equipment. For user interfaces, it’s usually a computer system or electronic devices.
Both user interfaces and human machine interfaces play an important role in modern-day technology. They offer an effective way for humans to control machines and devices. Without an interface, our devices would be virtually useless. Thankfully, though, this isn’t a problem, as human machine interfaces and user interfaces have come a long ways over the years, now offering an effective means of control.