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How to debug the electromagnetic flowmeter

Electromagnetic flowmeter debugging faults mainly have the following reasons:
First, the environmental aspects
Mainly due to pipeline stray current interference, space electromagnetic wave interference, large motor magnetic field interference. Pipe stray current interference usually takes good grounding protection to obtain satisfactory measurement. However, if there is strong stray current in the pipeline (such as electrolysis workshop piping), it may not be able to overcome the flow sensor and pipeline insulation measures. Space electromagnetic wave interference is generally introduced through a signal cable, usually protected by a single layer of shielding, but it has also been encountered that shielding protection can not be overcome.
Second, the piping system and installation aspects
Usually the fault is caused by the incorrect installation position of the electromagnetic flowmeter sensor. The common one is to install the flow sensor at the high point of the pipe network which is easy to accumulate the retained gas; the back pressure of the flow sensor, the liquid is discharged straight into the atmosphere, forming the measuring tube is not full. Tube; installed on the vertical pipe from top to bottom, may cause emptying and other reasons.
Third, the fluid aspect
The liquid containing uniformly distributed fine bubbles usually does not affect the normal measurement. However, when the measured volume flow is the sum of the liquid and the gas, the output signal fluctuates due to the increase of the bubble, and if the bubble is large enough to flow through the electrode to cover the entire electrode surface, The electrode signal loop is momentarily disconnected and the output signal will produce more fluctuations.
When two or more liquids are used in the pipeline mixing process, if the conductivity of the two liquids (or each of them is different from the electrode chapter potential), the flow sensor is measured before the mixing is not uniform, and the output signal also fluctuates. Low-frequency (50/16～50/6Hz) rectangular excitation electromagnetic flowmeter will produce slurry noise when the liquid contains more than a certain amount of solids, and the output signal will also fluctuate to some extent. The electrode material and the measured medium are poorly matched, and chemical effects such as passivation or oxidation, formation of an insulating film on the surface of the electrode, and electrochemical and polarization phenomena may hinder normal measurement.

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