If one is searching for a level sensor, you can be quickly overwhelmed by the huge selection. A level 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 decide on a level sensor, the most important selection criterion may be 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 a level switch. However, if it’s important to monitor the contents of a tank at length (e.g. 0 ? 100 % fill level), the other needs continuous measurement (= level sensor).
The distinction between level sensor and level switch automatically results in the exclusion of many technologies, if one wants 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 form 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 for example 4 ? 20 mA or 0 ? 10 V, which permit the accurate measurement of level and its variation. The sensors could be based on many different 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 the field of switches, additionally, there are many different measurement technologies such as for example reed contact technology, optoelectronics, conductivity, vibronic and more.
Each of these technologies has benefits and drawbacks, as well as complex, application-specific limiting factors such as conductivity, dielectricity, density, contamination, colour, pressure strength, etc. เครื่องมือที่ใช้ในการวัดความดัน as to which technology is most suitable or may be used in a particular application environment can only just be produced after thorough assessment and often also your final test in the plant itself under real application parameters.
Note
WIKA offers you a very 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 could find videos on the functionality of the average person measuring principles on our YouTube channel. Your contact person will be pleased to help you on selecting the most likely product solution.