Electromagnetic flow meter having a circuit that provides positive and negative magnetic excitation electric currents to a magnetic excitation coil

摘要

With the non-magnetic-excitation period until a specific amount of time elapses from the commencement of the transition from the positive magnetic excitation period to the non-magnetic-excitation period defined as a first period T1 and the non-magnetic-excitation period until a specific amount of time elapses from the commencement of the transition from the negative magnetic excitation period to the non-magnetic-excitation period defined as a second period T2, the sum of a voltage produced at a detecting electrode and a voltage produced at a detecting electrode, at the time of each first period T1 and second period T2, is calculated as a sum of voltages between electrodes, and a fault in an electromagnetic flow meter, such as detection of an empty state, adhesion of an electrically insulating object to an electrode, and so forth, is evaluated based on the sum of voltages between electrodes.