Measurement System Based On Virtual Instrument Technology Mpt

Over the past two years there has been an MPT (microwave plasma thruster) expreiment system in EPRC (Electric Propulsion Reaserch Section). In order to make further experimental study on MPT, EPRC update the old MPT measurement system. Taking account of the uncertainty of the experiments, the flexibility and expansibility are required. The virtual instrument technology is applied to construct the new MPT measurement system.The contents of this paper include:1. A new measurement system was developed, which was based on a PC and equiped with an AT-MIO-16E-10 multifunction I/O borad and other peripheral instruments.2. The limitation of the traditional measuring software was analyzed, and the intergrating idea and method of measuring function and the function of experiment projects management, as well as experiment data management were proposed, on the base of which the new MPT experiment system was developed with Labwindows/CVI, Powerbuilder, Excell 2000 and Access 2000.3. Then with the new system, eight group working data of MPT in atmosphere and vacuum environment were acquired. The data show that there is a minimum of reflected microwave power for helium when the flowrate increases, but for argon the reflective microwave power decreases while the gas flow increases in the special flowrate range. At the same time, at the approximate microwave power the reflected power under atmosphere enviroment and that under vacuum enviroment are diferent, 'which maybe result from the enviroment pressure disturbing the plume shape and electron density in it to change the electromagnetic characteristics of the resonance chamber.The experiments proved that the MPT measurement system is feasible and prepared for the future research.