| 摘要 |
PURPOSE:To obtain high accuracy and to reduce the load on a microcomputer by inputting the high-level period and low-level period of pulses regarding the output of a counting means to the microcomputer by a time counting means. CONSTITUTION:A charging comparing means selected by a selecting means compares a voltage regarding the capacity ratio of static capacity and fixed capacity with a voltage which is varied with a two-way current from a discharging means and inverts its output level when they coincide with each other. The number of times of the inversion is counted by a counting means and when the specific number of times is counted, another charging comparing means is switched and put in similar operation. A charging means, on the other hand, performs variable operation so as to apply a charge based upon a variable voltage to the 1st or the 2nd static capacity and also resets the duty cycle value of the output of the counting means to, for example, 0.5. Then, the charging means sends out pulses which have the high period and low level period regarding the output of the counting means and the pulses are digitized by the time counting means and a temperature signal from a temperature sensor is used to perform specific arithmetic operation by the microcomputer, thereby obtaining a differential pressure signal after static pressure is compensated.
|
