LIS3DH Full Scale Data Output

[XSong.15]

Hi,

I am reading data out from two LIS3DHs. All works as expected until the full scale is set to +-16g.

According to the data sheet, when FS is 11 and low power mode is enabled, each LSb in the data output registers represent 192mg. Low-power mode gives a 8 bit output in the OUT_X/Y/Z_H registers. The maximum value of a 8 bit 2's complement number is 127, and thus the data output registers can in theory show 127*192mg = 24g. This exceeds the +-16g threshold. Does this mean that in low-power mode and +-16g full scale, the number in the data output registers can never exceed 16000mg / 192mg = 83? I am getting values such as 127 and -128 from the data output registers, which don't make sense to me.

I believe my register configurations are correct, as I was able to read (0, 0, 5) when the accelerometer is placed flat on the ground. 5*192mg = 960mg, which is close enough to 1g considering the limited resolution.

Regards,

Kevin S

[Miroslav BATEK · Accepted solution]

The functionality of the accelerometer is guaranteed up to +-16g.

In case the acceleration is higher you can read more than 16g but the accuracy, linearity and overall performance is not guaranteed.

[XSong.15]

Hi,

Thank you for the quick response. Just making sure I understand correctly, the accelerometer's data output does not cutoff at +-16g, but can go up higher. However any data outside of +-16g is not guaranteed to be accurate. Is my understanding correct?

Thank you,

Kevin S

[Miroslav BATEK]

Yes, your understanding is correct.