Nowadays, the most common tools used for industrial automation are PLCs (Programmable Logic Controllers). As PLCs get more and more common, sophisticated logic networks are replaced by highreliability devices built compact, having standardised in/outputs. Using these appliances, in addition to industrial machinery, whole production lines can be made automatic. However the control of processes can be handled by PLCs alone, in some cases human contribution and communication is needed. For these purposes, HMI (HumanMachine Interface) panels are used, which can be used to visualise and actuate PLCcontrolled processes. HMI panels can be regarded as a window opened to the system, through which man can communicate with the PLC, making debugging and understanding of the system0s behaviour more simple. As PLC and HMI panels are more popularly used together, the aim of this work is to explain the connection between them, through the example of a model train board. During the implementation of the project I was using the resources of evosoft Hungary Ltd., including Siemens PLC and HMI devices and Siemens Totally Integrated Automation Portal, used for programming those devices.