BME680 - accuracy of measurements when calibration level is 1

[piotr_s]

We are using BME680 sensor in our data loggers. I noticed, that it has to recalibrate quite often. The device lays in one place, in a typical room and there are no extreme VOC changes. The chart below shows IAQ index measured by the sensor. Parts of the chart mared with red are the moments when the sensor was re-calibrating. Questions:

• Is the data during the calibration process reliable - can we show this data to the end users as valid measurements?
• Is this behaviour of the sensor normal? As you can see on the chart below, it had to re-calibrate twice during few days

[Fredrik_T]

@BSTRobin 

HI Robin (or whoever can answer this question), 

We need your support to sort out this and other questions that we have regarding the BSEC/BME680 logic to be able to continue the global projects on building climate control. Piotr and his team are delivering the HW, that uses your sensors, to us. 

Thank you. 

Kind Regards 

Fredrik 

[BSTRobin]

Hello piotr_s, Fredrik_T,

Sorry for the delay reply.
You could trust the data when IAQ accuracy was 3.

[piotr_s]

Hi Robin,

in some cases it takes more than 30 minutes to calibrate. Please check the attached chart (periods in red - calibration level 1, gray - 2, blue - 3). The data make sense, even if the calibration level is 1 or 2.

How should we reat calibration levels 1 and 2? Are these compleatly unreliable or is the accuracy level different, but the datra can still be used?

[BSTRobin]

Hello piotr_s, Fredrik_T,

Automatic background calibration ensures that users experience consistent IAQ performance.
IAQ values with status 1 or 2 are not as accurate as those with status 3, IAQ values with calibration status 3 are recommended.