Discussion on fault detection methods for electromagnetic flowmeters

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　　Electromagnetic flowmeters are used in industry primarily for flow control, and the fluids they measure are often corrosive and abrasive. In practical applications, failures in electromagnetic flowmeters are often caused by corrosion and leakage, reduced insulation, electrode contamination, or the accumulation of foreign substances. Next, I would like to discuss with you the methods for fault detection of electromagnetic flowmeters; I hope everyone can participate and share their insights. 　　I. One of the specific methods of operation: Enterprises can conduct a comprehensive inspection of electromagnetic flowmeters once a year. The inspection items include: visual inspection, converter performance testing, calibration of measurement values, measurement of voltages at various points, measurement of insulation resistance, and verification of the circuit. During the inspection and adjustment of instruments, zero drift makes it very important to adjust the zero point (\"on-line zeroing\" requires the flow of the medium being measured to stop, which is difficult to achieve in practice). Therefore, online inspections often omit the checks related to the operation of sensors, and only perform calibration of the converter in order to compare the results of the online inspection with historical data and determine whether the instrument should continue to be used, repaired, or replaced. As for the sensors, whether to replace them is decided based on the degree of degradation in the insulation resistance of the measured excitation coils. 　　II. The second specific method of operation: Verify whether there are any abnormalities in the electromagnetic flowmeter through online inspection. For pipelines where the medium flow cannot be stopped, the flow sensor and the converter are inspected separately; the converter is tested using analog signal generators and other standard instruments to ensure high calibration accuracy (which depends on the accuracy of the analog signal generators). The sensor is checked by testing the electrode’s contact resistance, as well as the insulation resistance and copper resistance of the excitation coil including its connection cables. Additionally, the excitation current output by the converter is examined, and indirect methods such as checking the magnetic field strength are used. For pipelines where the medium flow can be stopped, access can be obtained through a pre-installed access hole near the sensor to inspect and clean the electrode and lining for contamination/deposition. 　　The above are the specific methods for fault detection of electromagnetic flowmeters. If you have any other questions regarding flowmeters, feel free to leave a comment; I look forward to exploring the ocean of knowledge together with you.