Nowadays the programmable logic controls (PLCs) are basic elements of the industrial automatics. Therefore at the Department of Automation and Applied Informatics of the Budapest University of Technology and Economics a few years ago some members of S7 1200 Siemens PLC family were purchased.
The goal of my thesis is to describe programming potential of this device and the MODBUS industrial communication protocol. A supervisory control, data acquisition (SCADA) program on the PC and a process control on the PLC with the aim of demonstration and education were created on the basis of these standards. Beyond that the aim is to get the largest platform independence possible, using the Java language, that also makes the creation of the graphical user interface easy.
In the first part of my thesis I explore the construction and operation of PLCs and then I describe the MODBUS protocol family, mostly the TCP version. Finally I go into details about the solving of the edited program on the PC and the PLC.