I am working on MP7217 Methane Sensor module. I have made its circuit to use it as bridge as given in the datasheet, as shown in image. The output i am getting across the terminals is around 0.112V, while working in laboratory conditions which has quite clean air.
As per datasheet , the module gives 12mV/% of methane with offset of 20mV.
Now I am unable to intrepret this data since 112mV/(12mV+20mV) comes out to be 3.5% of methane approx. 3.5% of methane means 35000 PPM of methane, which seems to be a quite higher value for lab conditions.
Kindly suggest me how should i understand this data to get my output in PPM of methane.
The potentiometer that you see in the image is to buck the 5V from power supply to 3V using LM317.
I have attatched the pin configuration that is given in the application note of MP7217.
It says that the bridge output is the sensor output, but I could not trace the exact making of bridge, since I could see the only two resistors R1 and R2 as given in the image.
Plus the readings were observed in the laboratory environment where such an high reading of methane is not expected. This stuff is confusing me.
