Since the measurement result of the electromagnetic flowmeter does not have much relationship with physical parameters such as water pressure, temperature, and electrical conductivity, it has strong reliability and high precision. There is no obstruction to the flow piece in the measuring tube, so there is no additional pressure loss in the flow meter. In the measurement process, only the pipe and the electrode are in contact with the liquid to be tested, so it is only necessary to select a suitable electrode material to have an anti-corrosion effect. In addition, the electromagnetic flowmeter has a long service life and low maintenance requirements. The three electromagnetic flowmeters are capable of measuring the flow of positive water. Moreover, compared with other flow meters, the way of outputting signals is more flexible.