If one is looking for a level sensor, you can be quickly overwhelmed by the huge selection. An even sensor for limit level detection or continuous measurement could be ordered in a number of technologies and design variants. But how do you find the appropriate level sensor for my application?
If one wants to select a level sensor, the main selection criterion may be the electrical output function. If Divulge 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’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 an even 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 ? 20 mA or 0 ? 10 V, which permit the accurate measurement of level and its variation. The sensors can be based on a number of measurement technologies such as magnetostriction, reed-chain technology, hydrostatic, ultrasound, radar and more ? Collapse 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 a variety of measurement technologies such as for example reed contact technology, optoelectronics, conductivity, vibronic and much more.
Each one of these technologies has advantages and disadvantages, and also complex, application-specific limiting factors such as 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 specific application environment can only be produced after thorough assessment and frequently also a final test in the plant itself under real application parameters.
Note
WIKA offers you an extremely 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 get videos on the functionality of the individual measuring principles on our YouTube channel. Your contact person will undoubtedly be pleased to advise you on selecting the most likely product solution.