Electronic – Does calibration involve fixing electronics or mechanical part

calibrationmeasurement

My question is not 100% related to electronics design but it might be because I don't know the answer.

I'm writing a simple research on anemometer calibration. The thing is all the resources I found are explaining the procedure as measurement setup and comparing with a reference but not fixing. For the sake of clarity I posed my question with the following scenario:

Let's say I followed the setup procedure, collected all the data and measured the anemometer's speed changes with respect to a reference and drew a regression line for the anemometer. But how will then actually fix this anemometer mechanically or electrically? The papers don't mention it. Is measurement and data acquisition enough for calibration? How will the anemometer function in a different (proper) way after these steps if there is no mechanical or electronic adjustment? Will the adjustment (fixing) be on software or electronics circuitry?

I mean: What will be the actual adjustment for an anemometer after collecting the data with respect to a reference?

I'm really confused. Any ideas?

Best Answer

One way to use the calibration is to make no physical adjustments to the device. Simply do a mathematical adjustment to all the measurements you take with the device.

For example, an anemometer measures windspeed. Say you have a 5 mph reference flow and a 10 mph reference flow. Say in the calibration measurement, the 5 mph flow measures as 6.5 mph and the 10 mph flow measures as 12 mph. You then determine that the measured speed (I'll call it vm) is related to the real speed (v) by

\$v_m = 1.1v + 1\$

For your "live" measurements you'll reverse this formula to get the real speed in terms of the raw measurement:

\$v = (v_m - 1) / 1.1\$

So if you get a raw measurement of 8 mph, you use your calibration to estimate that the real speed was about 6.4 mph.

Of course the correction I described is based on a very simple, linear model of the instrument errors. In the real world, you might need a more complex model to get a correction formula that gives really accurate measurements.