The Design Of Software And Interface Circuits Which Exist In Automated Transformation Of The Gas Flow Meter Certification Of Device

In this thesis, the gas flow meter certification of device that has automated certification is studied, this device is based on the original gas flow meter certification of device which belongs to the First Aircraft Institute of AVIC-1. Operational processes include: Operator inputs parameters, the computer automated regulates membrane valves, automatic-manual opens corresponding spray nozzle, regularly collects the temperature and the pressure which exists in front of spray nozzle of sound velocity and pressure which exists behind spray. If the gas flow is stable, the computer will collect gas flow temperature and pressure of the checked apparatus entrance, collects current of the checked apparatus exit, in order to calculate standard flow and measurable flow of the checked apparatus. Through making a comparison between the standard flow and the measurable flow, the flow coefficient of the checked apparatus are decided. The device can achieve automatic-manual opening spray nozzle of sound velocity, visualized operational interface ,printing certification of proof and alarming etc. The main jobs are following:First, we determine the import and output signals of the computer through analyzing the working principle of the gas flow meter certification of device. We design the collected circuits on inputting signals and output signals are connected, which adopt Yanhua IPC-610 desk-top, 2700 data collection system and SR91PID regulator.Second, we prepare the driving procedures of interface circuits by Labview. We finish collecting signals such as temperature, pressure, differential pressures etc. We also achieve output of digital signal and analog signal.Third, software is designed. The first step the flowchart is determined. The second step we achieve automatic-manual selecting check points by programming, and automatic-manual opening spray nozzle of sound velocity, then calculate standard flow and measurable flow. The last step the flow coefficient of the checked apparatus is determined, and we print the certification of proof.Forth, procedures are debugged and operated.