A human-machine interface (HMI) is a user interface, dashboard or device that allows an operator to monitor and control a manufacturing process or a machine. The term HMI is almost exclusively used in an industrial context. It can refer to a standalone display, an embedded PC, an industrial PC, a computer program, a web-based interface, etc.
HMIs connect to programmable logic controllers (PLCs) to obtain data and to control processes by adjusting their operation parameters. Some of the typical information shown on an HMI’s interface are real-time process data, alerts, KPIs and inputs/parameters.
Nowadays, HMIs are normally linked to the company’s information systems to centralize process monitoring and control. With this kind of setup, engineers can oversee all manufacturing processes from a central control room without walking the plant floor. This approach increases productivity, reduces human errors, and lowers costs.
In recent years, technological trends like mobile devices and cloud computing have influenced HMIs. They now include capacitive touchscreens that are easier to interact with compared to their older resistive counterparts. They can also be accessed and controlled remotely, even from mobile devices. In the next years, HMIs are expected to gain augmented and virtual reality capabilities.
Industrial PCs are, just like their name implies, computers designed to be used in industrial environments. They are usually robust and compact. Nowadays, they also include touchscreens for easy interaction; this is especially useful when they also work as HMIs. However, they can also work with a more traditional keyboard and mouse setup. When included with a specific machine, like a CNCs, they are usually embedded into the machine´s chassis and equipped with specialized motion control cards and custom software.