If Strongly Suggest is looking for a level sensor, one 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 I find the appropriate level sensor for my application?
If one really wants to select a level sensor, the main 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 is important to monitor the contents of a tank in detail (e.g. 0 ? Unleashed fill level), the other needs continuous measurement (= level sensor).
The distinction between level sensor and level switch automatically results in the exclusion of several 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 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 4 ? Sneaky 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, there are also various measurement technologies such as for example reed contact technology, optoelectronics, conductivity, vibronic and much more.
Each of these technologies has advantages and disadvantages, together with complex, application-specific limiting factors such as for example conductivity, dielectricity, density, contamination, colour, pressure strength, etc. A reliable statement concerning which technology is the most suitable or may be used in a particular application environment can only be produced after thorough assessment and often also your final test in the plant itself under real application parameters.
Note
WIKA offers you a very wide range of level measuring instruments. Further information 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 individual measuring principles on our YouTube channel. Your contact person will undoubtedly be pleased to help you on the selection of the most appropriate product solution.