Multi-channel Pneumatic Flow Pressure Test System Pc Software Design And Calibration

Along with the computer technology, network, the virtual instrument technology development, multipoint pressure testing become the research focus, the paper mainly describe the design of the multi-channel pressure test system, which mainly realizes in the absolute pressure environment, real-time monitoring the gas pressure of the multiple channel, This paper firstly expounds the pressure test technology and virtual instrument technology development, and then introduced the whole framework of the system, the design and function of the PC software, finally introduces the system calibration.The system mainly consists of two parts, the pressure scanning module and the host computer. The entire system consists of two32-points pressure scanning modules which have the same function, so the system can collect the pressures of64channels at the same time.The development of PC software base on the software platform of virtual instrument,it is the Lab Windows of CVI in the WINDOWS operating system. The PC software complete the main functions are:first, with the network protocol of TCP/IP,establish a connection for communication between the host computer and the pressure scanning module; second, the pressure scanning module receives the instructions from host computer to configure the parameters of the pressure sensors, and the host computer complete the task of saving and reading these parameters; the PC software also real-time display the trends of different channels’pressure; and then save and process the collected data; besides that, the system can achieve the purpose of automatic pressure calibration and range migration, and the calibration coefficients are updated. To achieve the function of the entire software, the functional partitioning, sub-module and the overall debugging were used, these make overall structure clear and improve the efficiency of system development.It is necessary to calibrate the test system unregularly, but the manual calibration method is insufficient because of the many channels in the system, this paper describe using the principle of least squares fit, through the software to realizes semi-automatic calibration, and making the system measurement accuracy meet the requirement.