If one is searching for a level sensor, you can be quickly overwhelmed by the huge selection. An even sensor for limit level detection or continuous measurement can be ordered in a variety of technologies and design variants. But how do you find the appropriate level sensor for my application?
If one wants to decide on a level sensor, the most important 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 considered a level switch. However, if it’s important to 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 leads to the exclusion of several technologies, if one is looking for 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 form is limit level measurement only.
The selection of the best option 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 could be based on a range of measurement technologies such as for example magnetostriction, reed-chain technology, hydrostatic, ultrasound, radar and more ? Concealed 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 many different measurement technologies such as for example reed contact technology, optoelectronics, conductivity, vibronic and much more.
Each of these technologies has benefits and drawbacks, in addition to complex, application-specific limiting factors such as for example conductivity, dielectricity, density, contamination, colour, pressure strength, etc. A reliable statement concerning which technology is most suitable or may be used in a particular 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 an extremely wide range of level measuring instruments. Further information on optoelectronic level switches, hydrostatic level sensors, float switches and further instruments can be found on the WIKA website. You can get videos on the functionality of the individual measuring principles on our YouTube channel. Your contact person will be pleased to advise you on selecting the most likely product solution.g