I have an application (measureing the chimney draft)
where I have to measure really low pressure-differencies
-20 to + 20 Pa = 0.0002 bar = 0,2 mbar
right now 'm using this differential-pressure sensor
has a function
//Auto correct pressure drift lwlp.autoCorDrift();
But this autocorrection of drift seems not to work reliably
I discovered that this pressure-sensor has a drift over a longer time. (10 days)
After power off/on with no differential pressure applied I was able to re-calibrate it.
For automating this process I would need an extra valve that switches between measuring and calibrating
So if somebody knows of a sensor with a smaller differential-pressure range -50 Pa / + 50 Pa
that also has longterm-stability of the measured differential-pressure this would be a really good solution.
Second best solution is a small elektromagnetic gas-valve that switches between measuring pressure inside the chimney and outside the chimney for calibration.
As the pressure is so small I have doubts if a standard pressured air valve will work.
Maybe a small ball-valve moved by a RC-servo would be better suited.
best regards Stefan