What is HMI and SCADA?

Software plays increasingly important role in our daily life, filling slowly all of its aspects. In case of industrial installations its role is critical. Programmable process controllers (PPC) have replaced relay-based techniques. These controllers, along with the rest of the hardware and a software form complex, distributed systems.

HMI (Human Machine Interface) is one of the subsystems of such complex system. Generally the term refers to any set of means, which allow for interaction between a human and a machine. Today, in the context of computerized automation systems HMI is usually a display device with graphical user interface. The purpose of this device is to allow for a control over some process and visualize its parameters in a user-friendly fashion. Touch panels are currently most popular kind of devices, however HMI can also run on desktop PCs, laptops, tablets, smartphones and devices, which provide augmented reality.

SCADA (Supervisory Control And Data Acquisition) is another term related to industrial automation. While HMI can be conceptually narrowed to user interface, SCADA is a much broader concept. Its meaning is a bit fuzzy, but the role of the SCADA is to control whole process flow, propagate signals, collect data, store the data and perform data processing. SCADA can involve multiple devices, such as PPCs, field devices, database servers, HMI panels (HMI is an integral part of SCADA). It’s needless to say that these devices are connected in a network. They can talk to each other through different types of media and through many different types of protocols. A flexible software architecture is required to handle all the pieces of hardware and provide what is needed for the system.

CuteHMI vision

CuteHMI is meant to be a set of software components (libraries and executables) targeted at building HMI and SCADA applications.

These components aim to fill the gap, between open-source editions of Qt and commercial software targeted at physical computing (HMI/SCADA/IoT/BMS/RMS/etc) build around it, thus providing complete open-source suite for such types of applications for home and industrial use.

Example use case is to create user interface (HMI) that can be used to communicate with PPC to turn on air conditioning in the building for example.

Another use case is to create a daemon which collects the data from temperature sensors and exposes their actual values through Modbus protocol.

CuteHMI motto is: reusability, modularity, flexibility.