If one 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 could be ordered in a variety of technologies and design variants. But how do you find the appropriate 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 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 is vital that you 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 results in the exclusion of several 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 definitely 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 4 ? Revealing or 0 ? 10 V, which permit the accurate measurement of level and its variation. The sensors could be based on various 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 offer 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 much 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 concerning which technology is the 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 an extremely wide selection 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 find videos on the functionality of the average person measuring principles on our YouTube channel. Your contact person will undoubtedly be pleased to advise you on the selection of the most appropriate product solution.