| 摘要 |
A force measuring instrument for determining the strength of an applied force by measuring the strength of an electromagnetic force developed so as to counterbalance the applied force, the instrument including a force coil, a displacement sensor for detecting any displacement occurring on a scale balance, an analog arithmetic unit for performing PD operation of analog detecting signals sent by the displacement sensor, a pulse converter for converting the analog signal into a signal having a frequency depending upon the magnitude of the analog signal, an up/down counter for counting up or down pulse signals from the pulse converter depending upon the polarity of the analog signal, a D/A (digital-to-analog) converter for converting the number of counts by the up/down counter into an analog signal, and wherein the sum of the output of the D/A converter and the output of the analog arithmetic unit is fed back to the force coil, thereby ensuring that the counts by the counter alone are used to determine the measurements.
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