The Design Of Multi-fuctional Meter For AC&DC Parameters Based On Labview

With the construction of intelligent electric grid, the equipment and instrumentis developing rapidly. A large number of instruments made show a great improveme-nt in quality and quantity. Their results are important for people to guarantee safetyin production, decide quality of power and examine accurancy of apparatus. Theseparate detection can not satisfy the requirements of automatic and intelligentdetection, on the compicated power-parameter. There are shortcomings that moreequipments, complex operation, low efficiency. This created market demands fordeveloping an AC&DC multi-fuctional device. And the development of VirtualInstrument lays the technical foundation for the exploitation of the multimeter.The device is consisting of two parts: one is the Data Acquisition system basedon embedded technique of DSP and VI software based on LabVIEW. The DataAcquisition Card is used to collecting and sending data. The software is devided intofive big modules, AC analysis, DC analysis, DC component analysis, comprehensiveanalysis of parameters, timing module, based on idea of modularization. Amongthem, the main body of software contains the hardware driver and applicationprogram. The drive program which developed by LabVIEW VISA are used to driveand control DSP. In application program, the calculation, analysis, display andstorage of measurement results are achieved, using diverse Labview interface andparameter measurement algorithm, windowed FFT, power compensation, anti-pulsemoving average algorithm. Ultimately it can measure and display the parameterssuch as amplitude, frequency, phase, power, PF, harmonic, the unbalance factor ofthree-phase AC and amplitude, the ripple factor of one-phase DC. In addition to that,it can be used as timer.The paper depicts firstly the status of instruments and the lacking of traditionaldevice, which lead to the need for AC&DC multi-functional meter. Comparing theperformances of kinds of parameter measurement algorithms, a suitable one arechose, depending on the requirements of design. Then, the general structure of thesystem is expatiated. Specially, the realization scheme of VI software is introduced.The analysis of the actual testing results finally shows the method of VI can meet the demands of function and precesion.