If one is looking for a level sensor, you 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 wants to decide on 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 the level sensor should actually be a level switch. However, if it is 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 results in the exclusion of many technologies, if one wants 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 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 ? Blacklisted or 0 ? 10 V, which let the accurate measurement of level and its variation. The sensors could be based on a range of 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 the field of switches, additionally, there are a range of measurement technologies such as reed contact technology, optoelectronics, conductivity, vibronic and much more.
Each one of these technologies has benefits and drawbacks, along with complex, application-specific limiting factors such as conductivity, dielectricity, density, contamination, colour, pressure strength, etc. A reliable statement concerning which technology is most suitable or can be utilized in a particular application environment can only just be produced after thorough assessment and frequently also a final test in the plant itself under real application parameters.
Note
WIKA offers you an extremely wide selection of level measuring instruments. Further information on optoelectronic level switches, hydrostatic level sensors, float switches and additional instruments are available on the WIKA website. You can get videos on the functionality of the average person measuring principles on our YouTube channel. Your contact person will be pleased to help you on selecting the most appropriate product solution.