Error in raw data IIS3DWB

[GThabet]

Hello,

 

I am encountering strange samples in the raw data using the IIS3DWB accelerometer. I can make several requests for raw data without issues, but at a certain point, I receive data with incorrect values at specific sample positions.

 

Whenever an error in the raw data is observed, strange behavior can also be seen in the RMS data. Even without vibration, the sensor maintains a DC level in the RMS values. This persists for a few minutes and sometimes a few hours before returning to normal.

 

This error has a well-defined behavior in the raw data, with a value of 2560 observed every 32 samples for the gravitational axis, and a value of 0 in the raw data of the other axes also every 32 samples. The frequency and duration of this behavior are exactly the same as the behavior described for the RMS data. Sometimes I go several days without observing this problem, but sometimes it happens more than once a day.

 

Is this behavior a known issue? Do you have any tips on where this problem might be?

 

Thank you.

[Federica Bossi]

Hi @GThabet ,

Welcome to ST Community!

It's not a normal behavior or a known issue. Can you please share a screenshot of this? Or your log just to plot the data?

Thanks

[GThabet]

Hi @Federica Bossi, thanks!

 

Here is the screenshot of the RMS data. You can see that after 18:00 yesterday, 07/03, there is a DC level in the acceleration of the Z-axis, and also an offset in the Z-axis velocity. This axis is being influenced by gravity.

Attached are the raw data collected just now from the Z and X axes. I wanted to send the Y-axis data as well, but it is not allowed by the forum. From 18:00 until now, the offset remains, but sometimes it lasts only a few hours or minutes and then returns to normal.

 

Through the raw data, it is possible to observe the described behavior, with the value 2560 among valid raw data for the Z-axis, and the value 0 among valid raw data for the X-axis.

 

Thank you.

 

[GThabet]

Hi @Federica Bossi,

It has been a month and no response! Do you have any updates?

I identified that these problematic values are already present in the accelerometer FIFO.

Thanks.