Research On Integrated On-line Detector For Temperature Humidity And Grain Moisture Content Of Granary Based On Differential Method

There is food in my hand,I don't panic in my heart.Safeguarding food security is an eternal issue for China.China's grain production is increasing year by year.How to effectively ensure food security is the research focus of grain storage workers.Grain storage in the granary storage process will be affected by many aspects,such as biological and non-living fields,and these factors will lead to food fever,mildew and pests and diseases in the granary,thus endangering food storage.Therefore,a set of RF granary temperature and humidity and grain moisture on-line detector is studied to timely observe and collect the grain moisture in the granary,the ambient temperature and humidity in the granary,which is very important for safe grain storage.In this paper,a real-time online detection of grain moisture,granary temperature and humidity in grain storage process was developed.A set of RF granary temperature and humidity and grain moisture on-line detector was developed to realize on-line detection of multi-parameters of tempering wet water in granary.The main research contents are as follows:?1?The original theory of the granary temperature,humidity and grain moisture on-line detector.The basic principle of the detector for detecting moisture is based on the linear correlation between the dielectric constant of corn and its water content.The dielectric constant of water at room temperature is80F?m^-1,the dielectric constant of air is1F?m^-1,and the dielectric constant of plant tissue is2⁴F?m^-1usually.The dielectric constant of corn is mainly affected by its water content.When the temperature and the test signal frequency are constant,the water content increases and the dielectric constant increases accordingly.?2?The hardware design of the granary temperature,humidity and grain moisture on-line detector.The granary temperature,humidity and grain moisture on-line detector with STM32F103RCT6 embedded MCU as the core is designed.It adopts modular design ideas,including signal source module,differential phase detection module,voltage amplification module and core CPU module.On the measuring unit,the differential principle is adopted,and the concealed double-probe detection method is used to minimize the influence factors such as temperature and interference moisture measurement,and the granary moisture measurement is effectively realized.At the same time,through the analysis of the probe of the probe unit,the optimal parameters are selected to ensure accurate measurement.?3?Temperature,humidity and grain moisture on-line detector software design.The software also adopts the modular idea.Through the KEIL MDK V5 development platform,the library function is used to write the lower computer software,and the clock subroutine,voltage collection subroutine,serial communication subroutine,temperature and humidity subroutine are integrated to realize the granary.Software features for multi-parameter acquisition.The upper computer adopts LabVIEW system software design to realize data visualization and control the function of the detector,which provides guarantee for multi-parameter acquisition of granary.?4?Calibration of the temperature,humidity and grain moisture on-line detector.The grain moisture is measured strictly according to the specific operation steps of the moisture measurement in GB/T5497-1985"Food and Oil Inspection Moisture Determination Method".Through a single detector calibration system,the corresponding voltage values measured by the actual moisture and temperature,humidity and grain moisture on-line detector of corn were calibrated by least squares method,and the optimal mathematical model was established to minimize the error.?5?Experimental verification of temperature,humidity and grain moisture on-line detector.A small granary experiment was designed,and the detector was tested online for 48days of on-line detection of granary temperature,humidity and grain moisture,and the multi-parameter online detection of granary was realized.Comparing the actual moisture with the measured moisture of the system,the results show that the absolute absolute error of corn moisture content is 0.8%,the average absolute error is within 0.3%,and the average error meets the detection accuracy of±0.5%specified by the national standard.In addition to ventilation,the indicators are stable and the system stability is good.It can effectively detect the temperature,humidity and grain moisture parameters of the granary online.