Calibration of a moisture meter

[amon mazhara]

How can i calibrate the moisture meter, that is matching the moisture content percentage to the output voltage

 

[BradtheRad]

I guess you mean how do you make the meter read 80 V when the humidity is 80 percent?

That sounds too high.
So maybe not 80V, but 8.0 V?
Or 0.8 V?

You must select which volt level will represent 100 percent humidity.

You will need to adjust gain somewhere. Maybe the DC offset as well.

And you will need to check for linear performance. That is, whether your meter reading matches the humidity level. This can take a long time to collect a sufficient number of tests.

 

[chuckey]

use a set of wet and dry thermometers and some tables!
Frank

 

[jiripolivka]

To calibrate a sand-moisture meter, I requested the customer to make several plastic bags with wet sand. Each sealed bag was filled with sand of a known moisture (per cent water weight). In the calibration I obtained several sets of readings, then plotted a curve (X/Y plot) of calibration points, plus error bars.

If you calibrate an air-moisture meter, take a calibrated one and generate a column of air passing through both sensors. Record integer readings of the calibrated meter, along with readings of your meter. You might run the process several times and adjust the maximum reading of your meter for the maximum desired moisture.