[SOLVED] interfacing figaro TGS2600

[bagusdj]

hi guys, i would like to ask about few basic things.

i want to interface tgs2600 in a at89s52 mcu.

i want to ask about the Load Resistor needed. here is the datasheet:View attachment figaro tgs 2600.pdf

it said the RL is variative, min of 450 Ohm. is it free to choose the RL as long the Ps not exceeding 15mW and bigger than 450 Ohm, while also not exceeding 90k Ohm (RS)?

just want to make sure,since this sensor is difficult to acquire in my place.

i use this url as my reference

**broken link removed**

from the demo it looks that in 8bits,8channels adc the output will ranged 0-255. since smoke sensor reading should be in ppm, what formula that i need?
i googled about conversion and i found this https://digital.ni.com/public.nsf/allkb/397223D9826E1B4E86256F9400735FE5 is it the right calculation that i need?

 

[FvM]

is it the right calculation that i need

No, it's about ppm linearity measurements rather than gas concentrations.

Actually I don't think that a ppm calibaration makes sense for an unspecific air pollution sensor because each substance is measured with a different sensitivity.

 

[bagusdj]

No, it's about ppm linearity measurements rather than gas concentrations.

Actually I don't think that a ppm calibaration makes sense for an unspecific air pollution sensor because each substance is measured with a different sensitivity.

alright then.. how about the technical requirement for the sensor? am i right about it?

 

[FvM]

how about the technical requirement for the sensor? am i right about it?

The requirements are correct Vh and load resistor >= 450 ohm. There's no upper limitation for the load resistor, but in practice, you'll select a value that gives best sensitivity for the sensor. With a 8-bit ADC, the selection may be a bit difficult. I would start with 5 or 10 kohm.