Research On Control And Calibration System Of Piston Gas Flow Standard Device

Piston gas flow standard device has been widely used in recent years for itsadvatage, such as accurate value of the standard volume, good reproducibility, highpressure, flow stability, pressure stability and other characteristics.It can improve theaccuracy and effciency of calibration by using pistion gas flow standard device ascalibratiom device of diaphragm gas meters, float meter and soap film flow meterinstead of traditional gas standard device such as bell gas flow standard device.Thispaper designs a calibration and control system of piston gas flow standard device forcalibrating diaphragm gas meter, float meter and soap film flow meter.Fristly, the calibratiom models were proposed by analyzing working principleof piston gas flow standard device and calibration procedures of these meters and thesystem used a control scheme which was combined by DSP and LabVIEW. Secondly,the Motion controller base on TI’s TMS320F2812DSP was designed, the otherhardware of lower machine were bulit and the control program was completed. Thelower machine control system achieved motion control, valve control, analogacquisition and other functions. Then The upper machine calibration system adoptedthe graphical programming platform LabVIEW was designed, it realizedhuman-computer interaction, calibration control, data display and processing, and soon.The experimental results show that this piston gas standard device has goodrepeatability and can provide pressure, temperature stable flow. In comparison withbell gas flow standard device in ZheJiang Institute of Metrology and Sonic nozzle gasflow standard device in Haiyan Meijie Testing Instrument Co., Ltd, the results show agood agreement. The control and calibration system designed in this paper has a goodperformance and friendly interface, it can achieve high accuracy and high efficiencycalibration of diaphragm gas meter, float meter and soap film flow meter. At present,the control and caliration system has been put into operation and the system operatessteadily.