Design Of Electric Control System For Plant Spacing Of Air Suction Type Seed Metering Device

Agriculture is one of the basic economic pillars of our country,the production of grain is the country attaches great importance to.Improving the yield and quality of crops has always been at the heart of agricultural problems,especially during the epidemic period.Seeds,as a special means of production with vitality,have a direct impact on the yield and quality of crops.Therefore,the promotion and application of improved varieties and improvement of sowing methods are powerful ways to improve the development of production,which indirectly determine the structure and level of agricultural production.In this paper,a set of electric control system of plant distance of air suction cell seed metering device based on Siemens S7-200 smart programmable controller is designed for the problems of ground wheel slipping,missing seeding and low control precision.First,special sensors are selected to detect the advance speed of seeder,and the sensor transmits the pulse information to PLC for processing and analysis.PLC outputs command to the stepper motor driver to control the start,stop,speed and travel distance of the motor.A number of step motor driving modules are added to control the operation of each seed metering device separately.At the same time,Hall element is installed above the stepper motor to determine the current position of the motor.After receiving the hall signal,PLC drives the seed metering device to reach the zero position to achieve the goal of consistent row.The controller touch screen is installed in the driving position,which can set the operation speed and plant distance according to the actual requirements,which enriches the human-computer interaction experience.Finally,according to the characteristics of Siemens PLC,the ladder program of control system is completed by step 7-micro/win v4.0 software.The control system is coordinated with acquisition module,driver module and human-computer interaction module,which improves the control accuracy of seed metering device significantly.After the completion of the electronic control system for plant spacing of the seed platter,the Chinese cabbage seeds of "Qingza-3" were selected as the experimental object and the machine was moved to the JPS-12 test bed and the field for practical inspection.In the single factor test of the bench,when the rotation speed is between 25 and 30r/min and the vacuum degree is between 2.5 and 3k Pa,the performance indexes of the seed planting are all excellent.In the multi-factor combination experiment,when the rotation speed is 20r/min and the vacuum degree is 2.2k Pa,the seed arrangement performance reaches the best,and the qualified index is 93.02%,the replay index is 3.41%,and the omission index is only 2.79%.However,due to resistance and environmental factors,the performance indexes of field experiments are mostly lower than the laboratory level,but the results are close to the national crop single-grain precision sowing quality index requirements.