Electromagnetic flowmeter
Thread Content
The electromagnetic flowmeter gives unstable readings during measurement (it reaches full scale at times, shows no reading at other times, and remains at one value at yet other times). After taking it apart and checking it in water, the instrument functions normally. What could be the reasons for such issues? ? ?
:(Check the grounding and the electromagnetic interference in the surroundings... I think electromagnetic interference is the most likely cause)
If the installation is fine, it could be caused by air in the system; check whether the fluid medium fills the pipeline completely. It could also be the grounding issue mentioned by someone upstairs
LZ should explain the situation on site more clearly; this is very important for diagnosing faults using instruments!
It is suspected that one of the electrodes of the electromagnetic flowmeter is contaminated; in one case, the grounding is not proper, and a magnetic field cannot be involved – if such a field were present, it would have an impact after installation. At one point, it might be the instability of the process medium flow rate.
Dear Haiyou, if the electromagnetic flowmeter experiences the above problems, the causes are as follows: 1. The electromagnetic flowmeter is not installed correctly; for example, if it is placed at the highest point of the pipeline, there may be an issue of empty pipe conditions； 2. The substance being measured vaporizes very easily; the pipes and flow meters lack proper insulation, which causes the material to vaporize at this point and form bubbles ； 3. The conductivity constant of the substance being measured varies greatly, preventing the instrument from carrying out accurate measurements. I have experienced this; I encountered this issue when measuring chlorosilanes. Testing with water showed no problems (similar to the previous case), and the problem was resolved by changing the type of flow meter. 4. The phenomena caused by interference do not match what you said; the effects of interference are instability, with few periods of stability. 5. Issues with the instrument itself, such as improper adjustment of the damping coefficient or the conductivity threshold coefficient.
What was said upstairs covers everything; it includes pretty much all of it! First, check whether the installation was done properly, and whether it meets all the requirements
It could be caused by air traffic control issues, or it might be a grounding problem, interference, or air in the pipes
Is your flow meter in front of or behind the pump? Personally, it feels like bubbles; our factory sometimes behaves like that
Is your flow meter in front of or behind the pump? Personally, it feels like bubbles; our factory sometimes behaves like that
If the original poster finds the answer, please let me know.