300px-IPod_Touch_2G_BacklightIf you keep up with our blog here at Nelson-Miller, you are probably well aware of the general concept behind human machine interfaces (HMI). Not to be confused with graphical user interfaces (GPI), HMIs are used to provide a method of communication between a human operator and a machine. They are commonly found in factories and other industrial settings, with many companies relying on them to conduct their normal day-to-day operations. While there are subtle nuances between the different HMIs and how they work, most contain a combination of both physical and digital components.

Physical HMI Components

When speaking about HMIs, some of the physical components commonly used in its construction include membrane switches, rubber keypads, and touchscreens. Membrane switches perform the same function as a traditional switch, interrupting the flow of electrons. However, its membrane design means that it’s all a single piece rather than multiple pieces with multiple moving parts. Rubber keypads, of course, are the buttons used to press down on the switch, while the touchscreen is a surface on which a human operator issues touch-based commands. Membrane switches, rubber keypads and touchscreens are all considered to be physical components of an HMI.

Digital HMI Components

Of course, there are also digital components used in the construction of an HMI. This includes, but is not limited to, the software used as a medium through which the human operator controls the machine. Whether the HMI uses physical buttons or a touchscreen, it probably has software to help facilitate the process. This software is considered to be a digital component, simply because it’s not tangible and cannot be felt.

The Bottom Line…

Human machine interfaces have come a long ways over the years, implementing new features and technologies to enhance their usability. In order to understand HMIs, however, you must first look at their basic construction, which includes a combination of both physical and digital components. Physical components consist of things like membrane switches, rubber keypads and touchscreens, whereas digital components consist of software and other digital elements. Hopefully, this will give you a better understanding of the different physical and digital components used in the construction of HMIs.