LSM6DSL - values not correct

[Montanaro]

Hi :)

i m using LSM6DSL accelometer . i My sensivity is -2g/+2g. I have 16 bit (65535 values ) . Well, when i take values, i have values as:

65,423- 64,912 - 16,076

325 - 61,613 - 58448

I dont undestand this value. I think 16,076 is 1 g. And It's ok. But 65535 is 2 g ?

i m supponing 65 635 is 2 g, 32 500 is 0 g , 0 is -2 g.

It ' s correct ?

My real values are not correct ? or correct ?

How is the progession of values ?

[Petr S]

The data is in 16 bit two's complement which means that for example your reading is not 65423 but actually -113, which multiplied by sensitivity for FS 2g 0.061 equals -6.893 mg which is very close to zero. Another example of your data 16076 * 0.061 = 980.636 mg which is almost 1 g.

[Legacy member]

Hello,

Have a look at the AN5040: LSM6DSL: always-on 3D accelerometer and 3D gyroscope, section 4.5 Understanding output data.

https://www.st.com/content/ccc/resource/technical/document/application_note/group0/26/07/3f/bf/12/55/47/62/DM00402563/files/DM00402563.pdf/jcr:content/translations/en.DM00402563.pdf

It mentions the basic principle and show some examples.

In order to interpret the data, you also need to know the range you selected, which affects sensitivity. See section 4.1 Mechanical characteristics in the datasheet. https://www.st.com/resource/en/datasheet/lsm6dsl.pdf

David