I recently purchased some of these SEN0472 gas sensors to do some testing. I have the following issues / questions:

( In all testing the the sensors have been powered for at least 24hrs and zero PPM is confirmed with a known calibrated O3 sensor )

1. @ Zero PPM and temperature compensation OFF the sensors register a constant 0.1PPM concentration and 1.89V. Do I need to add an additional offset in my logic to account for this or should the calibrated sensor be returning 0PPM?

2. When temperature compensation is ON the readings @ zero PPM are .98PPM and 1.89V. Can the temperature compensation be used or not?

3. After 12hrs of constant polling via I2C the value for O3 get corrupted. See below @ zero PPM:

getSensorVoltage(): 1.89

readGasConcentrationPPM(): 256.00 (normally seen as 0.1)

readTempC(): 28.22

As you can see its not an I2C bus issue since temperature and voltage are returned correctly. Only a power cycle of the sensor will fix the data for O3.

4. Compared to our known calibrated O3 sensor the SEN0472 appears to give results that are double the correct value. For example if i read 3.5PPM on my handheld device the SEN0472 returns 7PPM.

5. Possibly related to the above….the sensor itself indicates 0-20ppm range. Is there any way with the existing carrier board to read that full range even if it sacrifices resolution?

6. Can the sensor itself be sourced without the carrier board? For example if we wanted to replace a worn out or damaged sensor?

7. Do you have specs on the sensor itself like PPM hours rating etc?

Thanks -AP