What are human machine interfaces and what does it do?

Do you know what a SCADA is? The very foundation of Industry 4.0 to control and gather precious data? Good, but do you also know what a human machine interface (HMI for short) is and can you tell it from a SCADA? No? Well, fear not, for the difference between what they do is significant, but it’s easy to mistake one for another. For the moment keep in mind that a SCADA controls and gathers data, while the HMI shows you the data and allows you to communicate witht the machine and vice-versa.

Why do we need an human machine interfaces?

Human Machine Interfaces are systems used by human operators to interact with industrial machines, allowing them to display the data gathered by their SCADA system running the whole line. This interface helps a human operator to act and take decisions whilst using an industrial machine (or line), through images, alarms, graphics or keyboards and control panels. Some examples can be the industrial computers installed on a line, the alarms triggered by emergencies and, as said before, the keyboards and control panels.

Let’s pay attention

Often the HMI is mistaken for the more famous and known SCADA, which is the analytic mind of a production line, while the Human Machine Interface acts as a control panel to monitor and control a production line. The HMI shows us how data are interpreted and gathered by the SCADA, and it’s this function that leads a lot of people to believe that they are the same system. Human machine interfaces, moreover, are not just based on a software that displays data and info to us, but also on the keyboards, the alarm signals and control panels needed to run a production line and fundamental to take the right decision based on the displayed signals.