Design And Test Of Control System Of Grain Sampler Based On PLC

At present,the grain sampler is usually used for grain quality inspection.The main principle is to insert the sampling probe into the grain pile for sampling,and then test the moisture and impurities of the sample to determine whether the grain quality can meet the storage standard.The subject originated from Juli Grain Machinery Co.,Ltd.,Jieshou City,Anhui Province.According to the company’s control requirements for grain sampler,and using industrial automation control technology,a set of high-precision,simple operation,and real-time display of working status was designed for the machine.The PLC automatic control system avoids the interference of human factors and improves the sampling efficiency.The work of the article is summarized as follows:(1)The grain sampler equipment was researched,and the overall control plan for grain sampling was determined according to the sampling requirements.The hardware circuit of the control system is designed according to the control scheme,and the selection of PLC,inverter and other hardware is completed according to the hardware circuit,the I/O address of the control center is allocated,the electrical schematic diagram is drawn,the design and manufacture of the electrical cabinet are completed,and carried out hardware installation and wiring.(2)Explained the principle of the communication protocol of the touch screen in the control system,solved the real-time communication problem between the host computer and the PLC and the inverter,wrote the PLC automatic control program and the touch screen program,completed the software design and the touch screen display.(3)Conduct field tests on the control system.The results show that the designed PLC control system can effectively control the grain sampler to achieve accurate sampling.The sampling frequency of the fan can be changed by the host computer in real time,and the frequency conversion control can be realized to improve the sampling efficiency.