If one is looking 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 is 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 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 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 ? Revealing , which let the accurate measurement of level and its own variation. The sensors could be based on various measurement technologies such as magnetostriction, reed-chain technology, hydrostatic, ultrasound, radar and more ? the choice 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 neuro-scientific switches, there are also various measurement technologies such as for example reed contact technology, optoelectronics, conductivity, vibronic and more.
Each one 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 as to which technology is the most suitable or can be used in a particular application environment can only just be made 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. 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 average person 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.