How to handle the malfunction of electromagnetic flowmeter signal output without display

The electromagnetic flowmeter shows small or no display, but in reality, there is no flow signal output. The causes of the malfunction include power supply failure and connection cable failure; Damaged sensor or converter components; The process reason is that the liquid flow state has changed, and there are problems with the adhesion layer on the inner wall of the process pipeline. The following methods can be used for inspection and handling.

1. Observe if there is a fault alarm display on the electromagnetic flowmeter, and perform corresponding checks and handling according to the meaning of the alarm code. There is no alarm display. Check if the power supply of the electromagnetic flowmeter is normal, if the switch is closed, and if the fuse is blown. Measure the voltage at all levels with a multimeter to determine the fault.

2. Power supply is normal, then check the connecting cables to see if the wiring of the excitation and signal cables is loose, and if there is any oxidation or corrosion at the terminals. If necessary, tighten the screws.

3. Check whether the resistance value of the excitation coil is normal, whether the coil is open circuit, whether there is a short circuit between turns, and whether the insulation resistance of the terminal or coil has decreased.

4. Newly installed or replaced sensors should be checked to ensure that the sensor arrow matches the direction of the fluid. Process coordination is required to determine whether the sensor is filled with liquid. Whether the sensor can be filled with liquid is related to its installation position and should be installed according to regulations.

5. The adhesion of dirt on the lining layer of the electromagnetic flowmeter sensor can cause a decrease in the insulation resistance of the flowmeter. The sensor can be removed for observation. When there is no condition to remove the sensor, the contact resistance and polarization voltage of the electrode can be measured, indirectly checking and judging the condition of the adhesion layer.