I wrote my thesis within Agrometal Food-Tech Ltd. In my thesis I introduce the pasteurization as a process, and the purpose of it. The structure of the pasteur needs such devices, that keep the standards of the pasteurization, so I introduce the operation, and the structure of these devices. Because the plant is needed to clean regularly, I introduce the structure and the operation of the CIP. Furthermore in every case, the product has to be tracked, we need sensors, which are as fast and precise as the procedure required. So I introduce which sensors are needed for the supervision and the control of the pasteurizer.
In the practise there is increasing requirement of the remote control (hot line), because we do not need to be phisically next to the plant to know what it is doing. So i designed and implemented the remote control, and the remote programming, and the local communication between PLCs through ethernet network.
After these i created the human-machine interface with NQ Designer, i implemented the program to a touchscreen terminal. This terminal and the PLC are communicating with each other, so the monitoring and the intervention can be used freely.
The milk, which is used for pasteurization, is need to heat, and keep at that temperature for a specific time. The heating is made by heat exchangers, and it is needed to regulate to hold the temperature. I use a PID controller for it. So I looked at the possible methods, I chose the right one, and by an example I determined the parameters. After that I introduced the built-in instruction of the PLC for the PID control.