level sensors

[Alex1015]

Most sensors on the market measure intermediate parameters: resistance, conductivity, pressure, capacitance, time interval and others. Their calibration is carried out in the field. Filling and draining liquid from the reservoir. This is quite labor intensive.

To what extent can level sensors that do not require calibration procedures be in demand on the market?

I don't mean visual level sensors (glass windows or tubes).

Let me explain my question in more detail.

I mean continuous level meters: hydrostatic, capacitive, conductivity, ultrasonic and others.
During manufacturing, sensors are calibrated by measurements of the signal (parameter) used.
For example, hydrostatic level sensors are calibrated to specified pressure values.
These results can be converted either into percentages or into units based on the density of pure fresh water.
In this case, on-site calibration may not be necessary if you are dealing with clean fresh water.

If you work with salt solutions, then the parameters of the solutions will differ significantly from the parameters of pure water. Sweating, conductivity, dielectric constant and others. The temperature dependences of these parameters will also change.

As a result, the liquid level values ​​will change and the temperature compensation of the sensors will not work correctly.

 

[waross]

Any known values within reason may be set in the calibration shop.
If the tank is irregularly shaped or of unknown non-linear shape and you wish to measure volume it may be nescessary to fill the tank to populate a look-up table.

--------------------
Ohm's law
Not just a good idea;
It's the LAW!

 

[jraef]

One of the worst level sensing systems I ran across, during troubleshooting of something unrelated, was a strain gauge transducer that sat at the bottom of the tank and had an atmospheric equalizing tube run up from it to auto-adjust for barometric pressure. I can't speak to how well that aspect functioned, but I can attest to the fact that once a spider laid her eggs inside of that tube, everything went to hell in a handbasket... I wasted 2 days at that site trying to test my portion of the project, which I couldn't do because the level transmitter kept falsely saying that the level was too high. Then I finally saw the tiny little spider crawl out of the end of that tube. I cut off about 6 inches of it and everything went back to normal. Looked in that piece of tube with a little flashlight and saw her egg sack.


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