P. Kosa, Z. Palkova, M. Olejar

Slovak University of Agriculture in Nitra (SLOVAKIA)
PLCs (Programmable Logic Controllers) are today the basic components of every industrial application. These controllers are supposed to drive whole working processes. The reason why they are used in several applications is that they are easy to program and via them we can easily make user friendly graphic interfaces. Considering to that, most of students and young people don´t know much about this problematic (working with PLCs and their application in industrial process). This is the reason why we decided to design and build a working model of pneumatic press controlled by PLC.

The aim of this work is to show to student or to any user, how can PLC, pneumatic cylinders, DC servo motor and microcontroller unit work together. The main principal of this process designed by us is: firstly the user has to put the semi-finished (SF) product that should be circular cross-section with maximal dimensions 20 x 30 mm (diameter x height) to presser chamber. Then the pressing process begins after that the final product is transported on the conveyer belt to a box. The final product is also circular cross section with unchanged dimensions, because it shows only the principal of pressing.

The whole system is controlled by PLC from Siemens and its extending modules. We use analogue and Ethernet module. The analogue module is used for measurement of motors operating speed (rotates per minute). The Ethernet module is used only for communication via Ethernet.

The user interface is provided by user panel also from Siemens. It allows the user to control the whole working process and its phases and also to give the user feedback about what is happening at the moment. There are also three capacitive touch buttons that provides the control of the start and stop of the working process.

Finally this project is designed especially for educational activities, because it is simple to program and the student can easily learn how to work with it. Basically bachelor theses like this one can solve problem with the fact that students don´t have enough knowledge about these systems when they finish universities.