CO Gas Concentration Reading with the board P-Nucleo-IKA02A1.

[SLee.9]

Hello, 

​I'm trying to tuning CO​ Gas reading value with the board P-Nucleo-IKA02A1.

By the P-Nucleo-IKA02A1 BSP, Get_Gas_concentration function is belows..

​float Get_Gas_concentration(float gain, float sens){

return ((float)Get_ADC_value(ANALOG_GAS_VALUE_PIN)-Get_ADC_value(ANALOG_REF_VOLT_VALUE_PIN))*805664/gain/sens; }

What's the meaning of the constant, 805664, of above source code?

[Jiri HLADIK]

Hello,

This constant represents conversion from ADC value to voltage. One LSB of 12bit ADC powered from 3,3V represents 805,664uV

The value is multiplied by 1000 to have correct gas concentration reading in ppm

Best regards

ST support

[SLee.9]

Thanks for your quick answer.

[Dsaka.686]

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