Manufacturing plants today achieve more efficient production with increasing reliability by reducing the possibility of errors and the need for human intervention. In one of the largest Hungarian pharmaceutical company a high warehouse was built in order to improve the utilization of installation. Three fully automatic stacker machines can be found in this warehouse. The machines work with Allen - Bradley Compact Logix PLC (Programmable Logic Controller), whitch is in continuous operation. Hence any downtime can cause a serious loss of production, therefore preventing errors and a clear indication of them is an important task. In my thesis I analyzed the operating principle of the stacker machines, in particular the communication network and the multi-level error handling. I got to know the Rockwell Automation software environment and programs and I made some necessary changes in the program. In the case of Rockwell PowerFlex 753- Series frequency inverters due to the unreliable DeviceNet network I examined the possibilities to work with other bus systems. EtherNet network was selected, because it is also compatible with the inverters, so the DeviceNet network is less congested, and it is expected to eliminate the inverter startup errors.
At the beginning of the thesis I outline the functional architecture of the warehouse, particularly the communication between PLCs. Then I present the Rockwell PLC development environment, the programming modes used during the work and the available communication protocols, and the reason for the choice. Finally, I present relevant pieces of source codes, the PLC program, and explain the reasons for changes to the implemented program in details and evaluate the results.