Design And Deployment Of Ultrasonic Flowmeter Based On TDC-GP22

At present,the household meter on the market generally uses mechanical metering methods.The conventional mechanical metering method has an inherent defect problem that the pressure loss is gradually increased as the use time increases.The intelligent electronic flowmeter based on ultrasonic detection technology has the advantages of high precision,high sensitivity and wide range ratio,and can realize remote information management and meet the development trend of metering instruments with current market intelligence requirements.The main work of this paper includes:(1)Firstly,the research status of ultrasonic flowmeters at home and abroad has been fully investigated.Common ultrasonic measurement methods and filtering algorithms have been theoretically analyzed.The structure,working principle and different channel mounting methods of the ultrasonic transducer are described in detail.This paper designs the hardware system of the ultrasonic metering module and realizes an ultrasonic flow metering module based on the TDC-GP22 high-precision timing chip.The metering module adopts a direct time difference method to obtain a forward flow time difference of the ultrasonic signal in the pipe section,and obtains the fluid flow rate by formula conversion.The module hardware system includes an MCU module,a metering module,an LDO power module,an LCD display module,an NB-IoT communication module,and a data storage module.(2)Secondly,experimental research was conducted on the performance optimization of the ultrasonic timing chip register configuration.The GP22-EVA-KIT evaluation system was used to build a laboratory test environment.In the still water state(zero flow rate),the received echo number experiment and the comparator offset experiment were performed by changing the parameter configuration in the register 3 and the register 6.The 1000 experimental data read were analyzed by the evaluation indicators such as variance,mean square error and average absolute error.The results show that the parameters DELREL1,DELREL2,and DELREL3 in register 3 are set to receive the experimental data of the seventh,eighth,and ninth echoes,which show lower standard deviation,lower mean square error,and lower average absolute.Errors,the values are: 0.181,0.036,0.102.In the offset configuration experiment,similar variance,average absolute error,and mean square error were obtained for different offset values in the range of-8 mV to 7 mV.The main difference of the data is reflected in the average value of the time difference of flight.According to the experimental results,the optimum offset value in the range of-8 mV to 7 mV is-4 mV.At the same time,in order to avoid the experimental error caused by the amount of data,this paper also carried out three sets of different data volume comparison experiments.1042,5150 and 14335 data were read separately.The experimental results show that the three sets of data have better index consistency.Finally,the experimentally obtained raw data is processed by the Kalman filter algorithm.The experimental results show that the variance of the data is reduced from 0.131 to 0.019,and the burr phenomenon is obviously optimized,and the numerical stability is greatly improved.The experiment proves that the Kalman filter algorithm can effectively reduce the zero drift of the ultrasonic flow metering module.