| 摘要 |
PURPOSE:To simplify circuit constitution by detecting an unbalance component as resistance, and generating a signal for adjustment by a microprocessor and also generating a calibration value signal from a calibration value and the adjustment signal by the microprocessor. CONSTITUTION:The output signal of a strain measuring bridge 2 is applied from the secondary winding 8 of an input transformer 3 to an AC amplifier 10, whose output signal is phase-detected by a detection filter 11 to extract the unbalance component as resistance. Then, it is amplified by a DC amplifier 12 and compared by a comparator 13 with a reference value, and the result is read in the microprocessor 14 through an input circuit 17. Then, a voltage inputted to the feedback winding 9 of the input transformer 3 from a D/A converter 15 is increased or decreased corresponding to ''1'' of a digital value to correct the unbalance component of the resistance. The digital value outputted from an input/ output device when the output voltage of a DC amplifier 12 becomes equal to a reference value is displayed on a display device 22. |
