Expert’s answer: Capacitive level transmitter working principle

Mmm, a slightly more complicated question here. No problem, though, we’ll take a look at the capacitive level transmitter working principle! A capacitive level transmitter is an example of indirect level measurement. Most sensors read the level of the product. This one reads an electrical charge, which changes according to the level of the product. For accurate results, you need to know the dielectric constant of your product and the empty and full level values of your tank.

You can use this solution in a wide range of solids, liquids, and slurries. It works with a radio frequency signal (RF) applied in a capacitance circuit. Also, you can use it in products with either low or high dielectric constants, so it gives you lots of flexibility.

Capacitive level transmitter working principle
Courtesy of VEGA

Now for how it works. To complete the circuit, the capacitor needs two plates. The insulated electrode works as one plate, and the tank wall the other. If you have a nonmetallic tank, then you can use a reference electrode.

The transmitter sends an RF signal between the conductive probe and the tank wall, so it creates a low current through the dielectric product. When the level drops, the dielectric constant will decrease, causing a drop in current flow. This, in turn, creates a low reading.

The transmitter will detect such changes and translate the data into level values, converting to an analog output, for example. So this is the capacitive level transmitter working principle!

Want more information? If so, these companies offer capacitive level transmitters:

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