Design Of Automatic Weighing And Batching System Based On Fieldbus DeviceNet

Ingredient was the key link to determine the quality of products in industries of food, feed, rubber, building materials, metallurgy, chemical etc. Most of the traditional weighing and batching ways were manual ways and they had many disadvantages such as low proportioning accuracy, could not be monitored in real time and the historical data could not be realized tracing. In view of the above problems, this paper designed automatic weighing and batching control system which based on DeviceNet Fieldbus and it was equipped with DeviceNet unit of PLC as the master station and two remote weighing instruments as slave station. PLC accessed real-time data of remote weighing instrument through DeviceNet communication, controlled the feed weight and completed automatic batching. In the system, the host computer and the lower computer(master station PLC) were connected by Ethernet to realize the function of real-time monitoring, formula management, data collection, historical data query and so on.Research work of this topic mainly focused on:(1)The production process of leather auxiliaries was deep analyzed in in this paper. The overall design scheme of automatic weighing and batching system was formulated.(2)The control system was designed based on the overall design scheme. PLC, DeviceNet unit, weighing instrument, transducer, HMI and other main hardware of the control system were selected and designed. Hardware configuration was made for PLC and I/O distribution was made for control system. The connection circuit between PLC and transducer was completed and parameters of transducer was set.(3)The PLC control program, HMI and host computer monitoring software of automatic weighing and batching system was designed according to the production process of leather auxiliaries. PLC control program included the main program, analog processing, temperature PID automatic adjustment, pressure monitoring, feeding speed control and other functional modules. HMI program included the monitoring interface, the parameter setting interface and the alarm interface. The host computer monitoring software adopted Kingview 6.55 and it included recipe management interface, main monitor interface and historical data query interface.The system has been successfully applied in a leather auxiliaries production shop of Qingdao a leather company and it has been stably worked for more than one year. It improves the accuracy of the ingredients, efficiency of production and management level effectively.