A Human Machine Interface or HMI is defined as a feature or component of a certain device or software application that enables humans to engage and interact with machines. Some examples of common Human Machine Interface devices that we encounter in our daily lives include touchscreens and keyboards. HMI s utilized in the industrial context are mostly screens or touchscreens that connect users to machines, systems or devices. Factory operators use HMI s to control and automate machinery, as well as their production lines. HMI s can be simple screen displays mounted on machines in the factory, advanced touchscreens, multi-touch-enabled control panels, push buttons, computers with keyboards, mobile devices or a tablet.
A standard scenario involving an HMI takes place in many water and sewage treatment plants. These facilities often face challenges since water treatment involves numerous phases such as screening, pumping and the removal of various harmful microorganisms and residuals. Also, each phase of the treatment can take place in areas that are kilometres apart, which means monitoring of equipment and processes is a challenge. The HMI screen which is integrated in the SCADA system is usually connected to the PLC and the operator can then monitor water level, the pH, the water pump, the level of dissolved solids or a certain toxic chemical, remotely.
The water pump can be turned on or off based on tank levels using the Human-Machine Interface. In addition, the HMI usually displays alerts if the pH is below a certain level, and this can be adjusted using the touchscreen display. In this way, the HMI enables the operator to monitor and control the processes and phases of water treatment. Many modern-day industrial HMI s being developed for the smart-factory environment are multimedia rich. They allow users to receive integrated SMS alerts about the status of machines, email alerts, and also watch integrated videos of the processes on the factory floor. More sophisticated HMI s allow for remote control of multiple machines and operations on multiple sites, as well as analysis of factory operations. HMI s can also display dashboards with manufacturing and plant-related KPIs.
There are many advanced level HMI s on the market currently that allow for monitoring and control of factory machinery. The main benefit, in terms of investing in an advanced level Human Machine Interface with multiple capabilities such as the ability to monitor machines remotely and to output dashboards with KPIs, is the simplification of factory processes and operations.