Daily maintenance and maintenance of electromagnetic flowmeters - Solutions - Huaqiang Electronic Network

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1. Routine Maintenance

It is important to periodically inspect the electromagnetic flowmeter to ensure it operates correctly. Check the surrounding environment of the instrument for any dirt, moisture, or foreign substances that could interfere with its performance. Make sure the piping is not leaking and is fully filled with fluid. Inspect the wiring connections for any damage or loose contacts. Also, check if there are any new sources of strong electromagnetic interference or wires running close to the device.

If the measured medium is prone to depositing on the electrodes or building up on the inner walls of the measuring tube, regular cleaning is necessary to maintain accuracy and prevent malfunctions.

2. Fault Diagnosis

If the flowmeter starts to show abnormal behavior after installation or during operation, first perform a visual inspection of the external components. Verify that the power supply is stable, the pipeline is intact, and no air bubbles are present in the system. Check the signal cables for any damage and ensure the converter output loop is properly connected. Avoid disassembling the flowmeter without proper guidance, as this may cause further issues.

3. Sensor Inspection

Testing Equipment Required: A 500MΩ insulation resistance tester and a multimeter.

Testing Procedures:

(1) When the pipe is completely filled with the medium, use the multimeter to measure the resistance between terminals A, B, and C. The resistance between AC and BC should be equal. If the difference exceeds 100%, it might indicate electrode leakage, condensation on the outer wall of the measuring tube, or issues in the junction box.

(2) In dry lining conditions, measure the insulation resistance between AC and BC using the MΩ meter (should be greater than 200MΩ). Then, use the multimeter to check the resistance between the two electrodes in terminals A and B and the measuring tube. It should be in a short-circuit state. If the insulation resistance is low, it suggests electrode leakage, and the entire flowmeter should be returned to the factory for repair. If the insulation is reduced but still above 50MΩ and step (1) shows normal results, the outer wall of the measuring tube may be damp. Dry it using a hot air blower.

(3) Measure the resistance between X and Y using the multimeter. If it exceeds 200Ω, the excitation coil or its wiring may be open or poorly connected. Remove the terminal block for further inspection.

(4) Check the insulation resistance between X, Y, and C. It should be above 200MΩ. If it drops, dry the inside of the casing with hot air. In practice, a decrease in coil insulation can lead to measurement errors and unstable output signals.

(5) If the sensor is found to be faulty, contact the manufacturer for assistance. Most issues cannot be resolved on-site and require professional repair.

4. Converter Inspection

If the converter is determined to be faulty and all external causes have been ruled out, contact the manufacturer of the electromagnetic flowmeter. Typically, the problem can be resolved by replacing the circuit board at the factory.