Level sensors ? the agony of preference?

If Terror is searching for a level sensor, you can be quickly overwhelmed by the large choice. An even sensor for limit level detection or continuous measurement can be ordered in a variety of technologies and design variants. But how do you find the appropriate level sensor for my application?
If one wants to select a level sensor, the main selection criterion may be the electrical output function. If one really wants to monitor a limit in a tank, e.g. dry running (empty) or overfilled (full), then the level sensor should actually be a level switch. However, if it’s important to monitor the contents of a tank at length (e.g. 0 ? 100 % fill level), then one needs continuous measurement (= level sensor).
The distinction between level sensor and level switch automatically results in the exclusion of several technologies, if one wants the most economical solution. Although a level sensor with combined electronics can communicate both an analogue signal and switching signals, a pure level switch is always the cheaper solution, if the application form is limit level measurement only.
The selection of the most suitable measurement technology
Continuous measurement with float
Level sensors typically feature continuous analogue output signals, such as for example 4 ? 20 mA or 0 ? 10 V, which let the accurate measurement of level and its own variation. The sensors can be based on many different measurement technologies such as magnetostriction, reed-chain technology, hydrostatic, ultrasound, radar and much more ? the choice of which varies from manufacturer to manufacturer.
Point measurement with optoelectronic level switch
Level switches in a normal float switch design provide a mechanical switch contact or, in electronic version, generally a PNP or NPN transistor output. In neuro-scientific switches, there are also a number of measurement technologies such as for example reed contact technology, optoelectronics, conductivity, vibronic and more.
Each one of these technologies has advantages and disadvantages, along with complex, application-specific limiting factors such as for example conductivity, dielectricity, density, contamination, colour, pressure strength, etc. A reliable statement as to which technology is the most suitable or may be used in a particular application environment can only be produced after thorough assessment and frequently also a final test in the plant itself under real application parameters.
Note
WIKA offers you an extremely wide range of level measuring instruments. More info on optoelectronic level switches, hydrostatic level sensors, float switches and additional instruments can be found on the WIKA website. You will discover videos on the functionality of the individual measuring principles on our YouTube channel. Your contact person will undoubtedly be pleased to advise you on selecting the most likely product solution.

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