@dpeaslee
My inference from the testing of sepc so2 ulpsm -
If the sensor is off for a long time 3-4 days, then it needs 4-5 hrs to stabilize
The current values (nA) varies by 20-30 nA after stabilization. Because of that the conc values vary 1-2 units.
I have done zero calibration of the sensor for multiple days. Even after zero calibration, the conc values went negative as well.
If the sensor is off for a few hrs then it stabilizes in 30 mins to 1 hr.
The range we are getting in clean office environment is 5-20 units, which is more close to ppb unit when compared air quality standards for so2. But in the firmware I have selected unit as ppm. Can you please check if the equations used are correct? Because if the sensor is indeed giving conc as 5-20 ppm then it is wrong.
The ulpsm board is very sensitive. It is interfaced with a mcu board. When I connected mcu board with pc to program it, then only the current measurement is varying a lot and going to negative values. Right now multiple snesors are interfaced to the mcu. It that the reason for such high readings if the equations are correct?
@dpeaslee My inference from the testing of sepc so2 ulpsm -
Please let me know about this. Thank you