Operator panel, control panel, or HMI (Human Machine Interface) - is a group of electrical devices enabling the control of industrial devices responsible for the technological and manufacturing process. The operator's panel comes in various forms, it can be part of a set of control elements of specific device units The purpose of such a device is always the same: human (operator) communication with the machine The operator controls using HMI processes e.g. production based on many signals or parameters displayed on specialized displays. The forms and components of operator panels (HMI) are specific and characteristic of machines and devices controlled by them, mainly classified into the category of industrial automation devices. Modern control panels are most often equipped with touch screens (Touchpanel). Touch panels and touchpaneles completely replace the functionality of the keyboard and buttons on the operator's cover. A touch on the screen transmits control signals. The machine control keyboard buttons (including e.g. sliders, potentiometers, joysticks, numeric keypads) can be displayed on the screen. In some HMI solutions, the display screen only has an informative function, providing relevant information, signals and parameters from the device to the man (operator) serving them. The matrices of these displays are also very device-specific. They differ in size given mainly in inches and type of matrix work (e.g. LED, LCD, Plasma). The screen can be integrated into the machine or be a separate monitor. A common solution in industrial plants are even older generation CRT (cathode ray tube) monitors or more modern but less economical PDP (plasma) monitors. The most common group, however, are LCD (liquid crystal) monitors with TFT technology and based on the OLED solution. HMI panels with appropriate software can be part of industrial computers. They usually have the functionality of connecting separate devices such as PLC controllers, communication modules, etc. The operator panel can also specify a separate device for controlling and controlling the work of e.g. inverters (inverters, frequency converters).