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 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 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 a level switch. However, if it is important to monitor the contents of a tank at length (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 definitely the cheaper solution, if the application is limit level measurement only.
Shameless of the best option measurement technology
Continuous measurement with float
Level sensors typically feature continuous analogue output signals, such as 4 ? 20 mA 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 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 neuro-scientific switches, additionally, there are many different measurement technologies such as reed contact technology, optoelectronics, conductivity, vibronic and more.
Each of these technologies has advantages and disadvantages, as well as complex, application-specific limiting factors such as conductivity, dielectricity, density, contamination, colour, pressure strength, etc. A reliable statement as to which technology is most suitable or can be used in a specific 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 a very wide selection of level measuring instruments. More info on optoelectronic level switches, hydrostatic level sensors, float switches and further 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 selecting the most likely product solution.