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The electromagnetic flowmeter is a new type of flow measurement instrument that developed rapidly in the 1950s and 1960s along with the advancement of electronic technology. It is made based on Faraday’s law of electromagnetic induction and is an instrument used to measure the volumetric flow rate of conductive liquids. Due to its unique advantages, it is now widely used in the measurement of flow rates of various conductive liquids in industrial processes, such as corrosive media like acids, bases, and salts ； Various slurry flow measurements have given rise to unique fields of application. Structurally, it consists of an electromagnetic flow meter and a converter. The sensor is installed on industrial process pipelines; its function is to linearly convert the volumetric flow rate of the liquid flowing into the pipeline into an induced potential signal, which is then sent to the converter via a transmission line. The converter is installed not too far away from the sensor; it amplifies the flow signal sent by the sensor and converts it into a standard electrical signal that is proportional to the flow rate, so that it can be displayed, accumulated, and used for control purposes. If the flow rate displayed as a negative value during the installation or operation of an electromagnetic flowmeter, there could be several reasons for this: 1. The sensor was not installed in accordance with the indicated flow direction, resulting in the measurement being taken in the opposite direction. Solution: Reinstall. 2. The sensor signal wires are connected in reverse; since the electromagnetic flowmeter has the capability to measure flow in both directions, it displays the reverse flow rate. Solution: Swap the signal wires. 3. The pipeline is empty or not fully filled, with gas present. At this time, the flow meter will display a negative value or the flow rate will fluctuate greatly. Treatment method: Fill the pipeline with the medium to be measured to enable the flow meter to function for measurement. Over half a cycle, the magnetic field is a steady DC magnetic field, which possesses the characteristics of DC excitation and is less affected by electromagnetic interference. Over the entire time period, the square wave signal is an alternating signal; therefore, it can overcome the polarization phenomenon that often occurs with DC excitation. Thus, low-frequency square wave excitation is a good method of excitation, and it is currently widely used. In summary, electromagnetic flowmeters have the following advantages: 1) They can avoid the orthogonal electromagnetic interference caused by AC magnetic fields ； 2) Eliminate power-frequency interference caused by distributed capacitance ； 3) Suppressing the eddy currents induced by the alternating magnetic field in the tube wall and within the fluid ； 4) Eliminate the polarization phenomenon caused by direct current excitation. For more information, please visit the company’s official website at http://www.yb1518.com/. Please retain this link when reproducing the content! http://www.yb1518.com/UploadFiles/2012717174126829.jpg