LIS2DH12: Measures higher accelerations than maximum range of 16 g

[Philipp D]

Posted on April 05, 2018 at 02:02

I'm currently testing the LIS2DH12 for a project concerning shock detection and measurement.

My first question is:

Which scaling factor do I have to use at the threshold registers and which one at the readout values for +- 16 g, Low Power mode (LP). Do I get this right that they are different?

Readout values: 192 mg / LSB

Threshold registers (INT1_THS, INT2_THS): 186 mg / LSB

My next question is about the maximum valid range

I tested the maximum readout values at +-16 g in low power mode at 5376 Hz.

Inside the OUT register I do have 8 bit-values of +127 or -128 at one or two out of the 3 axis.

That would mean: 127 x 0.192 g = 24.384 g

Is this value still correct because it's a bit more than 10 % above the maximum range of +- 16g?

Many thanks in advance for your help!

Posted on April 05, 2018 at 15:48

Hello,

Have a look at this answer to one of my previous question (it is related to a magnetometer, but the principle is the same).

https://community.st.com/0D50X00009XkXwiSAF

Long story short: boundaries are guaranteed as stated in the datasheet, the values outside the boundaries are not guaranteed to be meaningful.

David

[Philipp D]

Posted on April 05, 2018 at 16:12

Hi David, 

Many thanks for your reply!

Are you directly from the ST Support Team? I just wanted to know if this Info is officially valid because I want to use the solution in production Code.

Best regards 

Philipp 

Posted on April 05, 2018 at 16:16

Hello Phillipp,

I am notanST employee, however, the reply I linked you to was written by

Batek.Miroslav

‌, who is an ST employee, so I would consider this official.

Best Regards,

David

[Miroslav BATEK]

Posted on April 05, 2018 at 16:55

The functionality above the 16g is not guaranteed.

The output can be not linear and can vary piece by piece