Design Of Measurement And Control Software For Gas Dilution Device

Gas dilution instrument is a device for preparing mixed gases with different concentrations,which provides standard gases for calibration for gas analysis,gas detection and other instruments.The gas dilution instrument drives the actuator to complete the gas dilution under the control of the hardware circuit of the instrument by the control software.High-quality measurement and control software can not only make the user easy to operate,but also improve the measurement and control accuracy of the instrument through effective algorithms.In this paper,the domestic and foreign gas dilution instruments are reviewed,and the design of the measurement and control software requirements for the gas dilution instrument project is completed.The two gas dilution processes of “gas standard material preparation method based on permeation tube” and “ gas dynamic dilution method based on mass flow controller” were deeply analyzed,and the functional requirements of measurement and control software were analyzed.The overall framework of the measurement and control software is analyzed by using the ’ layered idea ’,and the software development environment is built.Allwinner T507 is used as the hardware platform for software development,and the Linux operating system is mounted on it.The measurement and control software is designed by using the open source and portability Qt development environment.Through the modular design of software functions,the operation mechanism of event-driven corresponding modules improves the readability and maintainability of software.The measurement and control software adopts the design method of single process and multithreading,which realizes the concurrent operation of the program and improves the real-time performance of the software.Database technology is used to store and manage the information of gas type,gas characteristic parameters and gas distribution scheme,which improves the independence of program and data.The measurement and control software realizes the networking of gas dilution instrument and client through the Internet of Things cloud platform,so that the dilution instrument can be remotely monitored.Multiple threads in the measurement and control software run reliably,threads run safely and synchronously.Database form access information is normal,query,modify and delete the function of normal use;the stable transmission of data is realized through the Internet of Things cloud platform,and the delay is less than 200 ms under normal circumstances.The overall design of the software adopts the idea of modularization,and the black box test method is used to test each module and the control system of the gas dilution instrument.The results show that the keyboard module has fast response speed,stable serial bus communication,small delay of remote control module,reliable information transmission,and fast and stable Flash reading and writing.In short,the control software operation in line with user habits,smooth operation,stable and reliable work,control dilution standard gas concentration to meet user requirements.