Abstract: To suppress the generation of bubbles of gas dissolved in a fluid, a flow evaluating portion compares a measured flow rate value with a preset reference flow rate value and determines whether a fluid is flowing through a measurement tube. When the flow evaluating portion determines that the fluid is not flowing through the measurement tube, a magnetic excitation controlling portion imposes a limitation so that a magnetic excitation current reduces to an electric current value less than a magnetic excitation current obtained in normal measurement. When the flow evaluating portion determines that the fluid is flowing through the measurement tube, the magnetic excitation controlling portion releases the limitation on the magnetic excitation current.

Abstract: To suppress the generation of bubbles of gas dissolved in a fluid, a flow evaluating portion compares a measured flow rate value with a preset reference flow rate value and determines whether a fluid is flowing through a measurement tube. When the flow evaluating portion determines that the fluid is not flowing through the measurement tube, a magnetic excitation controlling portion imposes a limitation so that a magnetic excitation current reduces to an electric current value less than a magnetic excitation current obtained in normal measurement. When the flow evaluating portion determines that the fluid is flowing through the measurement tube, the magnetic excitation controlling portion releases the limitation on the magnetic excitation current.

Abstract: In an electromagnetic flow meter, a signal amplifying circuit has an FET-input type differential amplifier wherein one input terminal is connected to a flow rate signal input terminal and the other input terminal is connected to a flow rate signal input terminal. An amplified output signal, which is obtained through performing differential amplification on the flow rate signals, is outputted from an output terminal. A fault detecting circuit detects a fault in the flow rate signal through comparing the electropotential of the amplified output signal to an upper limit reference electropotential and a lower limit reference electropotential.

Abstract: In an electromagnetic flow meter, a signal amplifying circuit has an FET-input type differential amplifier wherein one input terminal is connected to a flow rate signal input terminal and the other input terminal is connected to a flow rate signal input terminal. An amplified output signal, which is obtained through performing differential amplification on the flow rate signals, is outputted from an output terminal. A fault detecting circuit detects a fault in the flow rate signal through comparing the electropotential of the amplified output signal to an upper limit reference electropotential and a lower limit reference electropotential.

Abstract: Three-dimensional shape measuring instrument (white interferometer) for measuring the three-dimensional shape of an object to be measured by using white interference fringes, which detects the position where the amplitude of the white interference fringes takes on a maximum value with high accuracy in a short calculation processing time. An envelope distribution of the amplitude of the white interference fringes produced by the interference between the returning light from a reference mirror (6) and the returning light from an object (7) to be measured is determined, and an approximate position where the contrast of the white interference fringes is the highest is determined using this envelope distribution.

Abstract: Three-dimensional shape measuring instrument (white interferometer) for measuring the three-dimensional shape of an object to be measured by using white interference fringes, which detects the position where the amplitude of the white interference fringes takes on a maximum value with high accuracy in a short calculation processing time. An envelope distribution of the amplitude of the white interference fringes produced by the interference between the returning light from a reference mirror (6) and the returning light from an object (7) to be measured is determined, and an approximate position where the contrast of the white interference fringes is the highest is determined using this envelope distribution.