A Study On Appling PLC Of Belt Conveyor System's Energy-Saving Controlling In Port

Under the background of the nation initiating the green economy, circulation economy and the low-carbon economy, saving energy and resources has become an inevitable trend in the port industry. The belt conveyor system is the important part of bulk cargo terminal transferring the coal and ore, and so on. The belt load is fluctuating because the bulk cargo transfer is easy to be influenced by the site conditions. But the drive motor is still working with the power-frequency. It causes the waste of the electric energy and mechanical loss increasing. The drive motor is usually powerful, so research and tap the energy saving potential had the positive significance to reduce the energy consumption and improve the efficiency of energy utilization.According the requirement of one port in Xuzhou and taking their belt conveyor system 3# as the research object, the project develops and designs the automatic system which controls the frequency to the motor. The research bases on the PLC technology, frequency converter and configuration software technology are complementary. The main contents in research include grasping the composition, various parts function and working principle of PLC, the basic principle about controlling frequency of induction motor and the structure, functions and features of frequency converter; designing the whole solution, selecting the hardware and designing the circuit and preparing PLC control ladder figure procedure by STEP7; building the monitoring interface with the configuration software. Finally, the automatic system can be realized. The system can adjust the frequency of the motor and belt running speed in real time according to the material load on the belt. When the load is small, it can reduce the motor frequency and belt running speed; Otherwise it can increase the motor frequency and belt running speed.Through the design of this system, the understanding of frequency control technology and control design is deepened. It will also provide a theoretical guidance and technical support for the following design and application in future.