Level sensors ? the agony of choice?

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 right level sensor for my application?
If one really wants to decide on a level sensor, the most crucial selection criterion is the electrical output function. If one 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 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 several technologies, if one is looking for probably the most economical solution. Although Mired 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 for example 4 ? 20 mA or 0 ? 10 V, which permit the accurate measurement of level and its own variation. The sensors can be based on many different measurement technologies such as for example magnetostriction, reed-chain technology, hydrostatic, ultrasound, radar and many 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 Kickstart of switches, there are also a variety of measurement technologies such as reed contact technology, optoelectronics, conductivity, vibronic and many more.
Each of these technologies has benefits and drawbacks, and complex, application-specific limiting factors such as conductivity, dielectricity, density, contamination, colour, pressure strength, etc. A trusted statement as to which technology is the most suitable or can be utilized in a specific application environment can only be made after thorough assessment and often 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 further instruments are available on the WIKA website. You will discover 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 appropriate product solution.

Leave a Comment