Working principle: the measuring principle of electromagnetic flowmeter is based on Faraday's law of electromagnetic induction. the sensor is mainly composed of a measuring tube with isolation lining, a pair of electrodes installed by penetrating the wall of the measuring tube, a pair of coils and an iron core to generate a working magnetic field. As the conductive fluid flows through the measuring tube of the sensor, a voltage signal proportional to the average flow rate of the fluid will be induced to the electrodes. the signal is amplified and processed by the transmitter for various display functions.