SEN0472 Issues and Questions
AndrewPennell 2022-05-17 04:08:43 3996 Views6 Replies 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
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 ...The DFRobot SEN0472 is an electrochemical ozone (O3) gas sensor with I2C and UART interfaces that uses the Gravity interface. Common issues include inaccurate readings, with one user reporting values double that of their reference sensor, and data corruption, specifically for the O3 value after prolonged use. Other concerns involve offset values at zero PPM and questions about the usability of the temperature
https://spacebarcounter.org/
charlotte.emma Temperature compensation is meant to correct for temperature-related drift:
Your observation (~0.98 ppm at zero <a href="https://geometry-lite.io">geometry dash lite</a>) suggests compensation may be incorrect, overcompensating your baseline.
It may not be reliable under your conditions.
Try calibrating: record baseline over varied temperatures, then adjust or disable compensation.
tbas.casea If, under zero ozone conditions, the sensor outputs ~0.1 ppm and ~1.89 V:
This is normal behavior, reflecting a non-zero baseline offset.
The analog voltage at 0 ppm (V₀) for SEN0472 is around 0.7 V (following spec tables) geometry dash lite DFRobot Wiki.
The I2C/UART outputs are factory-calibrated, but they may still reflect a small offset.
Recommendation: Apply an offset correction in your logic—e.g., subtract ~0.1 ppm when reading is below a small threshold (say <0.2 ppm). No hardware modification needed.
tbas.casea Did you ever resolve the data corruption problem? I see the same issue with several different sensors all using I2C and the carrier board. Every instance of the sensors I've tried corrupts data after a few hours of use. My best guess at this point is a problem in the carrier board's firmware. I'm hoping you found a solution you can share before I start with tech support.
Thanks in advance :)
JohnRomkey 1. Because the sensor resolution is 0.1ppm, when the gas concentration is very low will display 0.1 instead of 0, and at the same time to pay attention to the impact of other interfering gases on the output value; the sensor is only calibrated for I2C and UART output data, if you use the analog voltage to calculate the gas concentration value, you need to add the offset to calculate, the specific calculation method in the product wiki has a relevant description https://wiki.dfrobot.com/SKU_SEN0465toSEN0476_Gravity_Gas_Sensor_Calibrated_I2C_UART#target_3
2.3. These two points need to consult technical support: [email protected]
4. Turn off the temperature compensation to try, and pay attention to the influence of other interfering gases, you can get information about interfering gases by consulting this document: https://dfimg.dfrobot.com/nobody/wiki/5953b463b8712f03d0791e98dd592e78.pdf
5. The default detection range of O3 sensor is 0-10ppm.
6. There are no separate probes for sale now, but you can tell [email protected]或[email protected] the quantity you need, and they will tell you the result.
7. The stability of O3 is <2%/month
Xiao 1. Because the sensor resolution is 0.1ppm, when the gas concentration is very low will display 0.1 instead of 0, and at the same time to pay attention to the impact of other interfering gases on the output value; the sensor is only calibrated for I2C and UART output data, if you use the analog voltage to calculate the gas concentration value, you need to add the offset to calculate, the specific calculation method in the product wiki has a relevant description https://wiki.dfrobot.com/SKU_SEN0465toSEN0476_Gravity_Gas_Sensor_Calibrated_I2C_UART#target_32.3. These two points need to consult technical support: [email protected]. Turn off the temperature compensation to try, and pay attention to the influence of other interfering gases, you can get information about interfering gases by consulting this document: https://dfimg.dfrobot.com/nobody/wiki/5953b463b8712f03d0791e98dd592e78.pdf5. The default detection range of the O3 sensor is 0-10ppm.6. There are no separate probes for sale now, but you can tell [email protected]或[email protected] the quantity you need, and they will tell you the result.7. The stability of O3 is <2%/month
Xiao 
