If one is searching for a level sensor, one can be quickly overwhelmed by the huge selection. A level 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 right level sensor for my application?
If one wants to decide on a level sensor, the most crucial 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 the 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 an even 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 for example 4 ? 20 mA or 0 ? 10 V, which permit the accurate measurement of level and its variation. The sensors can be based on a variety of measurement technologies such as for example magnetostriction, reed-chain technology, hydrostatic, ultrasound, radar and many 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 many 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 can be utilized in a specific application environment can only be produced after thorough assessment and often also a final test in the plant itself under real application parameters.
Note
Hurry offers you a very wide selection of level measuring instruments. More info 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 be pleased to advise you on selecting the most appropriate product solution.