Design Of Remote Diagnosis System By Comparing The Speed Of Sound On Gas Ultrasonic Flowmeter

As a clean energy natural gas is more and more popular in the customers who focus on environment protection.There must be a rapidly development for natural gas flowmeters.Among them,the ultrasonic flowmeter quickly occupied the natural gas metering market because of its high precision and easy maintenance.However,according to national regulations,the ultrasonic flowmeter must be returned back to the factory to be retested every two years,resulting in the efficiency is not high.And the prevalence of ultrasonic flowmeter wave problem.In order to solve the problems,this paper designs a gas ultra-sonic flowmeter remote diagnosis system based on the sound velocity comparing method.This article mainly completed the following work:Design the remote diagnosis system data acquisition function hardware and software.Choose WeegGA DTU as the data collector.And the communication between flowmeter and the slaves has been improved.Design the protocols and code the programs between masters and the slaves.Write the sound velocity comparing code and the server program.Based on the AGA Report No.10 the gas theoretical velocity calculation program is designed,and the difference is less than 0.1%.Based on the transit-time technique,program the flowmeter sound speed calculation.Based on eclipse development platform,write the diagnosis system server program with the C/S and B/S hybrid architecture.Test the remote diagnosis system.Run the data acquisition system in the laboratory,high temperature and the real environment,all succeed to receive the data.Analyze the data,have two conclusions:first,when the difference ratio between the two speed of sound is more than 0.2%,the flowmeter has to be returned back to retest;second,if the ratio is more than 0.7%,the flowmeter is in error.Finally,the system succeed to test the flowmeter in gas company being in normal status.