To determine and recover a failure in a differential pressure sensor including independent two pressure sensors.
A differential pressure sensor includes first and second pressure sensors disposed at first and second measuring points of a channel in which a fluid flows, respectively, differential pressure calculation means which obtains a differential pressure output from outputs of the first and second pressure sensors, correction means which is provided between the first and second pressure sensors and the differential pressure calculation means and performs level correction on the outputs of the sensors in accordance with a predetermined correction property, data storage means which holds beforehand discrimination data for discriminating the normality or the abnormality of the first and second pressure sensors, discrimination means which compares the corrected outputs of the first and second pressure sensors, the differential pressure output and the discrimination data to discriminate the normality or the abnormality of the pressure sensors, and correction property setting means in which an abnormality is discriminated, the correction property used for correcting the output of a pressure sensor corresponding to the abnormality is reset to the correction means.
Toshifumi Onuki
Akihiko Eguchi
Kazuhiko Naito