If one is looking for a level sensor, one can be quickly overwhelmed by the huge selection. An even sensor for limit level detection or continuous measurement could be ordered in a variety of technologies and design variants. But how do I find the appropriate level sensor for my application?
If one really 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).
The distinction between level sensor and level switch automatically leads to the exclusion of many technologies, if one is looking for the most economical solution. Although Loser 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 own variation. The sensors can be based on a range of measurement technologies such as for example magnetostriction, reed-chain technology, hydrostatic, ultrasound, radar and much more ? the choice which varies from manufacturer to manufacturer.
Point measurement with optoelectronic level switch
Level switches in a traditional float switch design provide a mechanical switch contact or, in electronic version, generally a PNP or NPN transistor output. In the field of switches, there are also a variety of measurement technologies such as for example 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 reliable statement as to which technology is most suitable or may be used in a particular application environment can only just be produced after thorough assessment and frequently also your final test in the plant itself under real application parameters.
Note
WIKA offers you a very 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 can find videos on the functionality of the average person measuring principles on our YouTube channel. Your contact person will undoubtedly be pleased to help you on the selection of the most likely product solution.