The Development Of Computer-testing System For Current Measurement Of Current-source In Synthetic Circuit

In this paper, the oscillatory circuit and synthetic circuit are analyzed theoretically at first and the main parameters of sythetic circuit under the conditions of the different current grades are gotten, that is not only the parameters' basis of synthetic circuit test, but also the important references of studying computer-testing system for current measurement of current-source in synthetic circuit.The most important and difficult contents of this paper are the research and development of the computer-testing system for current signal measurement of current-source in synthetic circuit. In the computer-testing system of current signal measurement of current-source in synthetic circuit, the following contents are included, such as Voltage-Frequency Converting Technique, Optical Fibre Isolating and Transmitting Technique, Singlechip testing and controlling, Plotting and Printing of sampled data on PC(Personal Computer). According to the test conditions, the double polarity inputting mode is adopted in the circuit of Voltage-Frequency Converting part; Storage batteries are used in the optical emission part of Optical Fibre Isolating and Transmitting device, that can guarantee isolation between the main circuit and the testing system; The 89C51 Singlechip is used in the Singlechip testing-controlling unit, the peripheral circuits are extended, data are transmitted through the serial port in this part; The popular software Delphi5.0 is used in the PC part, The communication between Singlechip and PC by serial port, plotting of current wave, regulation of data; the optical-electrical isolating and triggering are used in the controlling part, this can guarantee the veracity and reliability of breakers triggered, this triggering mode is also used in the triggering of the main closing breaker, the tested breaker and the assistant breaker, the triggering signals are sent out by a Singlechip. The design of software is mainly concentrated on data sampling, data processing, data transmitting of current signal, conversation between person and computer, plotting of wave and regulation of data, the software part can be divided into two main contents, which are programme in singlechip and programme in PC (Personal Computer).The whole large current testing system based on Voltage-Frequency Converting technique has been finished in this paper, and the DC voltage signals, PowerFrequency AC voltage signals are tested by this computer-testing system, the results are good, then the current of current-source in the synthetic circuit are tested by this computer-testing system. The results show that this testing system is fit for the test of DC signals, lower frequency signals and Power Frequency signals. The other merit of it is that it is fit for the test under the intense electromagnetism interference So, this computer-testing system would have the more popular applications in the high-voltage and large-current laboratories and the power system.The computer-testing system for current measurement of current-source in synthetic circuit has very important significance for the development of the computer-testing system of the whole synthetic circuit.