Patent ID: 7669455

Claim:
An automatic zero point correction device, comprising: a pressure sensor operable to measure fluid pressure, wherein output voltage from the pressure sensor is outputted to an outside and the sensor output voltage is inputted to a time-varying zero point drift correction means of the pressure sensor; a sensor output judgment means of the time-varying zero point drift correction means, wherein the sensor output judgment means operates to make a judgment to determine whether the sensor output voltage is larger than a set value; and operating condition judgment means of the time-varying zero point drift correction means, wherein the operating condition judgment means judges operating conditions of the pressure sensor, wherein the time-varying zero point drift correction means operates to cancel time-varying zero point drift of the pressure sensor when the sensor output judgment means determines that the sensor output voltage is larger than the set value and the operating condition judgment means determines that the operating conditions of the pressure sensor are within previously set operating conditions.