In this graduate thesis it is analysed the process of solving an engineering problem of regulating the flow and pressure on a specific industrial plant. The process is divided into 9 steps or chapters, which ultimately gives the idea of how to approach and solve a problem in the area of automation. In this thesis, it is used the knowledge from electrical and mechanical engineering. The paper deals with the analysis of the plant and describing the system itself, it’s requirements, and the working principle of the individual elements of the system. In this part, the system is divided into several parts, representing steel processing stages from the input to the system to the final product. After explaining the electrolytic processing of the steel strips, it goes to the overview of the market of the various PLCs used as systems for launching the software part of the control system. Here is an overview of possible forms of communication protocols in the system and the principle of connecting more complex systems to a common entity. Then explains the characteristics of certain central processor units of PLC devices and what characteristics to pay attention to. When the hardware and the features of the hardware are explained, it is explained the software part, where are mentioned the possible programming languages for PLC devices and the basic structure of a PLC program. Knowing the system and the hardware and software capabilities, the real system is simplified and it is created the system simplified model. The elements that will be used in the model of the system are defined, and some elements such as heat exchanger, safety proportional valve, pump, etc., are explained in detail. At the end, by knowing all the elements of the control system and knowing the system characteristics, the software and the system visualization are made, using the programs Siemens Step7 and Siemens TIA portal. A separate chapter is the determination of the mathematical model of the discrete PID regulator and its implementation in the software. An overview of the transition from time to discrete domain or the discretization of the PID controller, is given. Particular attention was paid to explaining PID regulator parameters and their impact on system time response. In the end, the system diagrams are displayed. The modes that are shown are: Automatic Mode, Manual Mode, and Security protocol for protecting the system.