Level sensors ? the agony of preference?

If one is looking for a level sensor, one can be quickly overwhelmed by the large choice. A level sensor for limit level detection or continuous measurement can be ordered in a variety of technologies and design variants. But how do I find the right level sensor for my application?
If one really wants to decide on a level sensor, the most important selection criterion is 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 considered a level switch. However, if it is important to monitor the contents of a tank in detail (e.g. 0 ? 100 % fill level), then one needs continuous measurement (= level sensor).
The distinction between level sensor and level switch automatically leads to the exclusion of several technologies, if one is looking for probably the most economical solution. Although an even 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.
Astounded 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 variation. The sensors could be based on a number of measurement technologies such as magnetostriction, reed-chain technology, hydrostatic, ultrasound, radar and more ? the choice of which varies from manufacturer to manufacturer.
Point measurement with optoelectronic level switch
Level switches in a normal 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 a number of measurement technologies such as reed contact technology, optoelectronics, conductivity, vibronic and many more.
Each one of these technologies has benefits and drawbacks, and complex, application-specific limiting factors such as conductivity, dielectricity, density, contamination, colour, pressure strength, etc. A reliable statement concerning which technology is the most suitable or can be used in a particular application environment can only just be made 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. Further information on optoelectronic level switches, hydrostatic level sensors, float switches and further instruments can be found on the WIKA website. You will find videos on the functionality of the individual measuring principles on our YouTube channel. Your contact person will be pleased to advise you on the selection of the most likely product solution.