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 number of technologies and design variants. But how do Off-the Record find the appropriate 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 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’s vital that you monitor the contents of a tank in detail (e.g. 0 ? 100 % fill level), the other needs continuous measurement (= level sensor).
The distinction between level sensor and level switch automatically leads to the exclusion of many technologies, if one is looking for 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 definitely 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 4 ? 20 mA or 0 ? 10 V, which let the accurate measurement of level and its own variation. The sensors can be based on many different measurement technologies such as 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 neuro-scientific switches, additionally, there are a number of measurement technologies such as reed contact technology, optoelectronics, conductivity, vibronic and more.
Each one 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 can be used in a specific 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 additional 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.