Experiment And Research Of Tea Tempering Baking Effect Based On PLC Control Device

After the tea is dried quickly,it needs to go through the process of slowing and cooling,so that the heat and moisture exchange and homogenization between the inside and the surface of the tea,and then slowly drying again,this process is called tea tempering.Tempering tea,also known as tea fragrance,can facilitate long-term storage of tea and improve the quality of tea.However,there are not many researches related to tea tempering,and the mechanism of tea tempering and aroma enhancement is still unclear.In order to solve the questions of difficulty to control temperature in tea tempering process and poor tea quality after tea tempering,designed the tea tempering roasting experiment based on PLC control system,and made relevant experimental research.By consulting a large number of relevant documents on automatic control technology in the field of agriculture and tea,developed a specific research plan and technical route.The main content and conclusions of the article are as follows:(1)In order to verify the rationality of the test bench design,a thermodynamic simulation is performed after operations such as meshing and setting boundary conditions.The simulation results show that the tea tempering test bench can provide a relatively stable wind field for tea tempering and a relatively uniform temperature field.The simulation results verify the rationality of the test bench design.Combined with the tea production process,the construction of the tea tempering test bench was completed.(2)Designed the overall control plan of the tea tempering control system,completed the hardware configuration of the control system and the selection of electrical components according to the requirements of the control system,the I/O address of the control system was allocated reasonably,the electrical wiring diagram was drawn,and the construction of the control system was completed.(3)The communication method of the control system is designed,the communication problem is solved,the PLC program and the touch screen program are written,and the software design in the tea tempering control system is realized.The Lab VIEW software platform is used to establish a data acquisition and storage system,which is convenient for data analysis after the test.(4)According to the actual and empirical parameters of green tea production,several experiments have been carried out to verify,the initial parameters of temperature PID control are set,and the effect of temperature PID is verified,which solves the problem of difficult temperature control during the tempering process of tea.(5)A test on the effects of tempering and baking of tea has been carried out,and the test results show that: The reasonable temperature range of tea tempering is 60℃-70℃,and the reasonable wind speed range is 2.21m/s-3.78m/s.The PID control tempering temperature is relatively stable,and the error between the preset temperature and the actual temperature is within ±5℃.Through the evaluation of the appearance,aroma,taste,leaf bottom,and color of the tempered tea,the comprehensive score reached 95.0 points.It can provide data reference for the design of tea tempering and roasting equipment.