| 摘要 |
The multicircuit type instrument of the invention is designed to measure the electric power, electric energy, power factor, reactive power, and reactive energy of one or more voltage lines of alternating-current three-phase electric circuit or alternating-current single-phase electric circuit, and circuits branched off from these voltage lines. The multicircuit type watt meter of the invention includes at least one line or more of voltage input means of alternating-current three-phase electric circuit or alternating-current single-phase electric circuit, current input means in the same number of voltage input means or more, input switching means for switching over the current input means, an A/D converter converting an analog output of the voltage input means and an analog output of the current input means into digital signals, and a CPU for controlling switching of the input switching means and controlling time shared multiplex sampling of the A/D converter, in which the current input means connected to the input switching means are switched over sequentially by the input switching means between a sampling point and a next sampling point in the basic time shared sampling of time shared multiplex performed by the CPU, and by performing time shared sampling same as the basic time shared sampling in cooperation with each switching, different circuits are sequentially sampled by time sharing, so that the plural electric power values are computed by the CPU from the simultaneous time shared sampling data. The CPU computes, instead of the electric power, the electric energy, power factor, reactive power and reactive energy, so that the multicircuit type instrument of the invention may be used also as the watthour meter, power factor meter, reactive power meter, or var-hour meter. <IMAGE> |
