If one is searching for a level sensor, one can be quickly overwhelmed by the large choice. 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 right level sensor for my application?
If one 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’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 probably 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 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 own variation. The sensors could be based on various measurement technologies such as magnetostriction, reed-chain technology, hydrostatic, ultrasound, radar and more ? Jail of which varies from manufacturer to manufacturer.
Point measurement with optoelectronic level switch
Level switches in a traditional float switch design offer a mechanical switch contact or, in electronic version, generally a PNP or NPN transistor output. In the field of switches, additionally, there are various measurement technologies such as for example reed contact technology, optoelectronics, conductivity, vibronic and more.
Each of these technologies has advantages and disadvantages, as well as complex, application-specific limiting factors such as for example conductivity, dielectricity, density, contamination, colour, pressure strength, etc. A trusted statement concerning which technology is the most suitable or can be utilized in a particular 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. More info on optoelectronic level switches, hydrostatic level sensors, float switches and further instruments can be found on the WIKA website. You will discover videos on the functionality of the average person measuring principles on our YouTube channel. Your contact person will be pleased to help you on the selection of the most appropriate product solution.