If one is searching for a level sensor, you can be quickly overwhelmed by the large choice. A level 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 right level sensor for my application?
If one wants to select a level sensor, the most crucial selection criterion may be 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 considered 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 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 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 more ? เพรสเชอร์เกจ 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 for example reed contact technology, optoelectronics, conductivity, vibronic and more.
Each of these technologies has advantages and disadvantages, 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 may be used in a specific application environment can only be produced after thorough assessment and frequently also your 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 additional instruments can be found 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 undoubtedly be pleased to advise you on the selection of the most likely product solution.