If one is looking for a level sensor, one can be quickly overwhelmed by the large choice. An even sensor for limit level detection or continuous measurement could be ordered in a variety of technologies and design variants. But how do you find the right level sensor for my application?
If one wants to select a level sensor, the most crucial 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 your level sensor should actually be considered a level switch. However, if it’s vital that you monitor the contents of a tank in detail (e.g. 0 ? 100 % fill level), the other needs continuous measurement (= level sensor).
Dangerous between level sensor and level switch automatically results in the exclusion of many technologies, if one wants probably 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 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 4 ? 20 mA or 0 ? 10 V, which permit the accurate measurement of level and its variation. Amp can be based on various measurement technologies such as for example 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 traditional float switch design offer a mechanical switch contact or, in electronic version, generally a PNP or NPN transistor output. In the field of switches, additionally, there are various measurement technologies such as reed contact technology, optoelectronics, conductivity, vibronic and more.
Each one of these technologies has benefits and drawbacks, together with complex, application-specific limiting factors such as for example conductivity, dielectricity, density, contamination, colour, pressure strength, etc. A trusted statement as to which technology is most suitable or may be used in a specific application environment can only just be made 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. Further information on optoelectronic level switches, hydrostatic level sensors, float switches and additional instruments can be found on the WIKA website. You can get 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.