Development Of Virtual Instrument For Electrical Parameter Measurement

Virtual Instrument is the measuring instrument based on computers. It has more advantages than traditional measuring instrument and has made great improvement in recent years. We develop the Virtual Instrument system of electrical experiments to satisfy the needs of experimental teaching development, and to realize the demands of intelligent and network experiment. The system can measure most useful parameters in electrical experiments, such as AC voltage, AC current, DC voltage, DC current, resistance, capacitance, inductance, and as well as having contained the function modules of digital oscilloscope and signal generating device.The hardware of system is composed of signal adjustment circuit, data acquisition card and computer. This paper expatiates the designing scheme of AC signal adjustment circuit, DC signal adjustment circuit and RLC signal adjustment circuit. In hardware design, we export the signals which control electrical relays to change measuring ranges of measuring instrument through the DO port of data acquisition card. We select AC6111 data collection card made in W&W LAB to collect measuring data of signal.We design the applicator program in VB6.0. The Virtual Instrument uses virtual panel as the interface of human-computer, and performs the tasks of signal measurement, waveform display and data store. The idea of modularized design is emphasized in this paper, including the data acquisition, range switching & control, digital filter, parameters measuring, linear revision and so on.In this paper, the auther lists the texted data in all the circuits of the instrument. The result shows the instrument adapts the design requirement.At the end of the paper, it proposes the main problems need to improve and the aspects need to reseach deeper.