In the thesis I write about the hardware and software design of an industrial MODBUS/TCP gateway device, which convert to a CAN-based control network. The first chapter explains the need to make a device. In the second chapter, I short present the structure of the two protocols between which the device performs the conversion. In the third chapter, I summarize the expectations and needs of the device and outline the system layout that I have designed. Chapter Four contains hardware planning steps. Here, I present at aspects of choosing a microcontroller and the Ethernet controller. Then the schematic diagrams for each hardware component can be seen. After that, I write about the main requirements for selecting the housing and drawing up the printed circuits board. Chapter Five describes the software architecture of the system. As a first, it contains a general system block diagram and can be read from the structure of the scheduler that forms the basis of the system. Then come the drive components that handle the peripherals. Then I write about the translation process, the tables and descriptors needed for translation. Finally, I will present the configuration task that allows you to change the settings. The sixth chapter is the user guide for the device, which can be used on its own if only the wiring and the configuration interface are to be read. The end of the document is located on the schematics, printed circuit board plans and parts lists.