| 摘要 |
PURPOSE:To detect an accurate ship speed by sampling the output of a semiconductor pressure sensor and the output of an atmospheric pressure sensor properly and subtracting the output value of the atmospheric pressure sensor from the output value of the semiconductor pressure sensor. CONSTITUTION:When a channel CH 1 is selected first for an ACE 3, the ACD 3 converts the voltage of the semiconductor pressure sensor 1 which is inputted to the CH 1 from analog to digital and outputs its digital signal, which is read in a speed arithmetic means 5. This obtained digital voltage signal represents pressure applied to an opening. Then a channel CH 2 is selected for the ADC 3 and the digital signal of the atmospheric pressure sensor is read in the means 5 similarly. This obtained digital voltage signal indicates atmospheric pressure. Then the difference between the pressure applied to the opening and the atmospheric pressure is calculated and the means 5 calculates the ship speed (v) from said value by utilizing an arithmetic data map 6. The calculated ship speed V is outputted as a ship speed signal, and the speed is displayed on a speed display means 7. Thus, the accurate speed is detected.
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