Magnetic Flow Meter Troubleshooting| Manufacturer’s Guide

Magnetic Flow Meter Troubleshooting|

Where should Magnetic Flow Meter Troubleshooting start?

As a kind of industrial electronic sensor equipment, electromagnetic flowmeter will inevitably have some equipment failure problems in the process of use. So when the electromagnetic flowmeter fails, we usually analyze which component has the problem. Then find a solution to the problem corresponding to the problem. Below, Sino-Inst will explain to you the common faults of electromagnetic flowmeters in daily life, and then how to deal with the faults.

Magnetic Flow Meter Troubleshooting Checklist

Phenomenon 1: Large flow fluctuations

Influencing factorsApproach
1. The medium contains excessive air bubbles or particlesChanged to vertical installation
2. The conductivity of the medium is uneven or close to the middle valueChange the installation location or reselect the model
3. Split line failureCheck the split cable and choose a cable with good shielding
4. Sensor insulation dropsReturn to factory for repair
5. Inverter interferenceChange the installation location or return to the factory for repair
6. The electrode is covered with dirt or corrodedClean and inspect electrodes
7. With pulsating flowIncrease damping time or fake pipe damper

Phenomenon 2: The flow rate display is too small

Influencing factorsApproach
8. The motor has foulingDescaling
9. The excitation part of the converter is faultyreplace converter
10. The inside of the watch body is dampDry out or return to factory for repair
11. Pipeline blockageCheck and clean the pipes to keep them clear

Phenomenon 3: The flow display is too large

Influencing factorsApproach
12. There is a small amount of air bubbles in the pipelineAdd exhaust
13. Scaling in the pipeline has conductive substancescheck pipes

Phenomenon 4: No flow display (instantaneous flow is zero)

Influencing factorsApproach
14. Meter setting reverseCheck gauge settings and correct
15. The flow rate is not enough to the tube, the measured medium is not filled to the electrode, and the empty tube alarmChange the installation location
16. The electrode is covered by an insulating mediumClean and inspect electrodes

Phenomenon 5: The zero point is unstable

Influencing factorsApproach
17. The medium is not full of pipeSet the air traffic control alarm and set the air traffic control threshold reasonably
18. The valve is not closedCheck the valve and close it
19. The pipeline vibrates greatlyfixed pipe
20. External magnetic field interferenceGround the flowmeter well
21. Severe fouling of electrodescleaning electrode
22. After cleaning the electrode, the electrode oxide film is destroyedIt needs to be filled with medium to soak the electrode for 24~48 hours

Phenomenon 6: Converter black screen, no display

Influencing factorsApproach
23. Power problem or lightning strikeInstall power protection or lightning arrester
24. Problems with the converter itselfreplace converter
25. High temperature or direct sunlight LCDImprove the installation environment
26. The fuse of the converter is burned outreplacement insurance
27. Liquid crystal damageReplace the LCD panel

Phenomenon 7: No flow output

Influencing factorsApproach
28. Power failureCheck whether there is a fault in the power supply part, test whether the power supply voltage is normal; test whether the fuse is on or off;
29. Check whether the sensor arrow is consistent with the fluid flow directionIf inconsistent, change the installation direction of the sensor;
30. No current output:Is there DC current at the IOUT and COMM terminals of the meter head after removing the load?
31. No pulse output:After removing the load, whether there is a direct voltage between the POUT and COMM terminals of the meter head;
32. 485 no output:(1) Check whether the parameter “communication address” in the header is correct;
(2) Check whether the data address in the communication protocol is correct;
(3) Use the 485 test software provided by the manufacturer to test whether it is normal;

Featured Magnetic Flow Meters

Learn More About Magnetic Flow Meters

Electromagnetic Flowmeters (EMF for short) is a new type of flow measuring instrument developed rapidly with the development of electronic technology in the 1950s and 1960s. Electromagnetic flowmeter is an instrument that uses the principle of electromagnetic induction to measure the flow of conductive fluid based on the electromotive force induced when the conductive fluid passes through an external magnetic field.

Magnetic flow meters use the principle of Faraday’s Law of Electromagnetic Induction to measure the flow rate of liquid in a pipe. In the magnetic flowmeter pipe parts, a magnetic field is generated, and channeled into the liquid flowing through the pipe. 

Faraday’s Law states that the voltage generated is proportional to the movement of the flowing liquid. A conductor moving through a magnetic field produces an electric signal within the conductor. And the singal is proportional to the velocity of the water moving through the field. 

As fluid flows through the magnetic field, conductive particles in the fluid create changes. This variation is used to measure and calculate the velocity of water flow through the pipe. When the fluid moves faster, more voltage is generated. The electronic transmitter processes the voltage signal to determine liquid flow.

What is the principle of magnetic flow meter? – Faraday’s Formula

Faraday’s Formula
E is proportional to V x B x D where:

E = The voltage generated in a conductor
V = The velocity of the conductor
B = The magnetic field strength
D = The length of the conductor

How does a magnetic flow meter work

To apply this principle to flow measurement with a magnetic flow meter. First is to state that the fluid being measured must be electrically conductive for the Faraday principle to apply.

As applied to the design of magnetic flow meters, Faraday’s Law indicates that:

the signal voltage (E) is dependent on V, B, D.

V is the average liquid velocity ;

B is the magnetic field strength ;

D is the length of the conductor ( which in this instance is the distance between the electrodes).

  1. The electromagnetic flowmeter has no mechanical inertia and is very sensitive to the reaction. It can measure instantaneous pulsating flow as well as flow in positive and negative directions.
  2. Industrial electromagnetic flowmeters have a wide range of diameters, ranging from a few millimeters to a few meters. There is an existing DC calibration device with a diameter of 3 meters. It laid the foundation for the application and development of electromagnetic flowmeter.
  3. The sensor of the electromagnetic flowmeter has a simple structure, and there are no moving parts in the measuring tube. There are no throttling components to block fluid flow. Therefore, when the fluid passes through the flow meter, it does not cause any additional pressure loss, and it is one of the flow meters with lower energy consumption among the flow meters.
  4. The output of the electromagnetic flowmeter is only proportional to the average flow velocity of the measured medium, and has nothing to do with the laminar or turbulent flow of the flow state under symmetrical distribution. Therefore, the electromagnetic flowmeter has a wide measurement range, and its ranging range can reach 20:1, and some even reach a range ratio of 100:1.
  5. Electromagnetic flowmeter is a volume flow measuring instrument. During the measurement process, it is not affected by the temperature, viscosity and density of the measured medium within a certain range. Therefore, the electromagnetic flowmeter can only measure the flow rate of other conductive liquids after being calibrated with water.
  6. It can measure dirty medium, corrosive medium and suspended liquid-solid two-phase flow. This is because there is no blocking flow component in the metering tube. Only the measuring tube lining and electrodes are in contact with the fluid to be measured, and materials can be selected according to the properties of the fluid to be measured.

For example, polytrifluoroethylene or polytetrafluoroethylene can be used as a lining to measure aggressive media such as various acids, alkalis and salts. The use of wear-resistant rubber as the lining is especially suitable for measuring the wear of solid particles.

Larger slurries, cement slurries and other liquid-solid two-phase flows and various suspended liquids such as fiber liquids and pulp.

If you cannot find an answer to your question in our Magnetic Flow Meter Troubleshooting, you can always contact us and we will be with you shortly.

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Electromagnetic flowmeters are suitable for measuring the volume flow of conductive liquids in closed pipelines, such as clean water, sewage, various acid-base salt solutions, etc.

The fluid that uses electromagnetic flowmeter to measure flow must be conductive. Therefore, non-conductive gases, steam, oil, acrylic copper and other substances cannot use electromagnetic flowmeter to measure flow.

Magnetic Flow Meter Troubleshooting always appears very headache! The causes of Magnetic Flow Meter Troubleshooting are various. Some are caused by the flowmeter itself, some are man-made, and some are caused by on-site reasons.

If you encounter the above faults in the process of using the electromagnetic flowmeter, you can gradually eliminate and solve them according to the methods given above. If you can’t solve it, it may be because the working conditions on site are too complicated. The electromagnetic field strength is too high. Pay attention to the grounding of the instrument, and you can also contact Sino-Inst to provide technical assistance.

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