BNO055 does not stay calibrated in Suspend Mode

[joshaltabet]

I use 2 BNO055's in my project and they are working as expected. The only issue I am facing is, everytime I put the sensors into suspend mode and then back into Normal power mode, the calibration for all sensors seems to be lost. If I fully calibrate the sensors, put them into suspend mode and do not move them at all, and then back into Normal power mode, they will stay calibrated. Otherwise, they do not. So I have the following questions. My goal is to have the sensors stay calibrated while putting them into suspend mode.

The sensors can be in suspend mode for a variable amount of time, anywhere from 5 minutes to 1 week.

1. Are calibration offsets valid (still usable) if set in Location A and Position A, completely turned off, and turned back on in Location A but Position B?
2. Are calibration offsets valid if set in Location A and Position A, completely turned off, and turned back on in Location B and Position A?
3. Are calibration offsets valid if set in Location A and Position A, completely turned off, and turned back on in Location B and Position B?
4. Should the accel, gyro, and mag stay calibrated if calibrated in Location A and Position A, put into suspend mode, and then put back into normal power mode in Location A and Position B?
5. Should the accel, gyro, and mag stay calibrated if calibrated in Location A and Position A, put into suspend mode, and then put back into normal power mode in Location B and Position A?
   
6. Should the accel, gyro, and mag stay calibrated if calibrated in Location A and Position A, put into suspend mode, and then put back into normal power mode in Location B and Position B?
7. Is amount of time in suspend mode a factor for sensors becoming uncalibrated in suspend mode?

[Vincent]

When sensor is fully calibrated,  you can read out the calibration parameters then stored in system memory.  

Then put sensor into suspend mode or power off.  

Before reenter the normal power mode,  write back the calibration parameters.  Then sensor will start with calibration level 3.  

But the calibration is always running in background,  if detect any offset value change or compensated value changed over threshold,  the calibration level will drop from 3 to 2 or even 0.  Then sensor will recalibrated itself until 3.  

Remember,  even just change the position,  the magnetic environment might be different.  this means sensor will drop the calibration level and recalibrated again.  

It is expected behavior. 

Sensor will keep calibration level only when it calibrated in location A, position A,  put into suspend mode,  then back to normal at location A, position A.  and there is no additional distortion nearby.