How to take a reading from MiCS 4514

[bhavika]

I am confused with MiCS 4514 sensor. What I had done is :

1. using MiCS quick start evaluation board, measured ADC value
2. calculated Vout and from that calculated R0.
3. Rs/R0 concentration gives me high value, which is not possible, My data is as follows
   clean air file is used for the purpose of R0 value
   https://drive.google.com/file/d/0B8sF8a6FHoseWjhWOHRoYzIxakk/view?usp=sharing

and Polluted file is used to calculate the actual pollution
https://drive.google.com/file/d/0B8sF8a6FHoseR1BnclhCUHdibEU/view?usp=sharing

I am confused. Please help me

[epierre]

is your R0 in Ohm or KOhm in your formula ?

[bhavika]

Its in ohm

[bhavika]

In clean air, I calculated the value of R0 by using MiCS quick evaluation board.

Formula applied :(ADC/(RESOLUTION - ADC)) * 51820---for NO2
and (ADC/(ADC-RESOLUTION))*100820 -- for CO

and in polluted air I applied same formula and gave it a name Rs

Then took ratio of Rs/R0 which is less than one.

So I had a slope and its constant meand y = m*x + c
But i do not know how to derive equation to find out the value of ppm from Rs/0