Research And Design Of Compositive System For Ultrasonic Gas Flow Meter Detection And Calibration

In recent years,ultrasonic gas flow meter has been widely used in industrial field because of its wide range,small drift and high stability.However,its performance was limited by the device dispersions and gas environmental factors.It is necessary to build a calibration and management system for ultrasonic gas flow meter to ensure its stability and accuracy,through the method of calibration and verification.Aiming at these problems,such as the complicated operation and low integration degree,exist in the calibration system,which is widely used in current enterprise.This thesis describes a integrated system of ultrasonic gas flowmeter's detection and calibration.For the purpose of mass integration calibration,intelligent automatic measurement,high stability and expansibility,we take modular design ideas to design the calibration system,which includes multi-channel analog switch selector,program downloading and protecting system,environmental parameters control system,gas flow control system based on OPENCV,operate-control system,data management system.According to the command from host computer,multi-channel analog switch selector chooses the corresponding communication channel to collect the flow meter's calibration data.Program downloading and protect system will protect the compiler while bulk downloading the program.The environmental parameters control system realizes the automatic control of the calibration system's environmental parameters such as temperature,concentration,pressure and flow.gas flow control system based on OPENCV realizes the automation of the flowmeter's sampling test.operate-control system based on VB realizes the coordination of calibration links,the monitoring of environmental parameters and product data.At the end of calibration,it outputs the calibration report according to the calibration requirements.The data management system realizes the storage,query,statistics,modify of calibration data.With effective data management,it is convenient to analyze from the data level to discover design problems,Processing problems,quality problems,which exist in the flowmeter and calibration system.All of this will provide the basis for the product optimization and system maintenance,optimization and improvement.The communication network take time-out mechanism,fault-tolerant mechanism and blacklist mechanism to ensure its safety and reliability.Through sampling the compiler's output current,the program downloading and protect system realizes the function of automatically programing and protecting the compiler.The application of optimized PI control algorithm in pressure flow control system realized the integrated control of gas pressure and gas flow.In the gas flow control system based on OPENCV,we using the self-designed moving target detection method to detect gas flow.In the operate-control system,we set up the link sequence table and the status table,to mark the system running state and system errors,guarantee the calibration process in an orderly manner.In the data management system,we take VB call SQL language way to achieve the function of data query,data statistics and data modify.We analyzed the subsystem's debugging data and the whole calibration system's debugging data.The data shows that the performance of calibration system meets the design requirements.In the long run and application process,we continue to optimize and improve system performance.Operating results show that the system is safe and reliable meets the production requirements and the purpose of the design.