Max. OUT Value for LIS2DS12 not as high as expected

Forum|Forum|5 years ago
November 12, 2020
1 reply
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We are using the LIS2DS12 in an environment where we sometimes exceed the configured range (i.e +- 8g).

We would expect to be the positive maximum OUT Value to be 0x7FFC and the negative maximum to be 0x8000. Instead the + max value is 0x7FE0 and negative max value is 0x8020.

Is this expected behavior?

Here is one example for one reading of all 3 axis and reaching the negative max. value:

OUT_X 0x8020

OUT_Y 0x811C

OUT_Z 0x2EC8

Example of positive max. value

OUT_X 0x5F08

OUT_Y 0x7FE0

OUT_Z 0x1360

Accelerometers

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Best answer by Eleon BORLINI

Hi @glalex ,

the vale you are measuring as maximum values are . In particular, 0x7FE0 is for example 7.988g, while 0x811C is -32484*0.244 = -7.926g.

So you have basically measured values that are a little below the +-8g full scale.

This is due to a couple of causes: first, at the edge of the g-scale of the LIS2DS12, there could be a little non-linearity that determines a "distortion" effect, causing the reduced full scale effect you are experiencing; second, the sensitivity calibrated during the production test could be little different from the declared 0.244g (for a MEMS effect).

These effects should be negligible if you can work for example 0.5g away from the Full Scale.

-Eleon

Eleon BORLINIBest answer

ST Employee