Hot:21152013-10-15 23:29:06 From: FTD Automation Instruments
Electromagnetic flow meter problem
In the application process ,Electromagnetic flowmeters usually will appear small problems, and these problems usually appear in the commissioning and dubugging period, if we can promptly eliminate the problem, these problems will not appear in the future.
Common debugging problem is usually caused by improper installation, environmental interference and fluid characteristics influence.
Installation: normally is caused by not correct installation location of electromagnetic flow meter sensors, for example, install the sensors to the highest point where is there is gas easily gathered.
Or installed in a top-down vertical tube, may appear emptying;
Or there is no back pressure on the sensors, and the measuring tube is not full.
Environment: there is stray current interference, strong electromagnetic interference, large motor magnetic interference, etc.
To fix the problem of Pipeline stray current interference, we can take good separate grounding protection; but for the powerful stray current (such as electrolytic workshop pipeline, sometimes in two electrode induced ac potential peak Vpp can be as high as 1 v),other methods need to be taken, for example, electromagnetic flow meter sensor is insulating from the pipeline, etc.
For Space electromagnetic interference, single or multi-layer shield can be used.
when measured liquid containing uniform distribution of the tiny air bubbles, it does not affect the normal work of the electromagnetic flowmeter, but if the bubble increase, then the flowmeter output signal will appear fluctuation, and if bubble big enough to cover the whole electrode surface, so bubble through electrode, can make the electrode loop instantly break which will makes the output signal appear larger fluctuation.
Edit by FTD Automation Instruments (www.ftdinstruments.com)