Is SCADA basically an HMI?
No, SCADA is not the same thing as HMI, but the two are very similar and typically work together in industrial automation systems. A SCADA (Supervisory Control and Data Acquisition) system is made up of many parts, one of which is an HMI (Human Machine Interface).
The HMI is the interface that lets operators engage with machines, see real-time data, provide commands, and keep an eye on processes. It is the visual dashboard or control panel. It can be used in several ways, such as on local screens, portable devices, or thin clients through a browser. HMI software like AVEVA Edge makes it easier to design and deploy these kinds of interfaces, which speeds up development and makes them available on the web.
On the other hand, SCADA is a bigger and more complete system. It has more than just HMIs; it also has PLCs, RTUs, data acquisition servers, communication infrastructure, data historians, alarms, remote telemetry, and even business-level connections like MES or ERP systems. SCADA collects, processes, logs, alarms, reports, and sometimes even directly controls equipment over large, often remote areas.
In short:
HMI is the screen you use to interface with.
SCADA is the whole system that connects users, data, devices, and logic.
Not every HMI is part of a SCADA system, but every SCADA system has one or more HMIs. HMIs can also be used in simpler control setups, like standalone machines or DCS (Distributed Control Systems).
SCADA and HMI technologies commonly work together in today’s factories, but knowing the difference between them will help you grasp how they fit into the bigger picture of industrial control systems (ICS).