[ADXL313] How to estimate the total error

Hi team,

I think the total error can basically be calculated as follows:

 Total error = offset + offset_temp_drift x ΔT + Sensitivity error + sensitivity_temp_drift x ΔT

So I have some questions.

Q1.

 I can't find the offset in datasheet and but instead find the "Initial 0 g Output".

Does "Initial 0 g Output" mean the same as offset?

Q2.

 What is the difference between "0 g Output Drift over Temperature" and "0 g Offset Tempco" in the table above?

Q3.

 How does the Initial alignment error affect sensitivity and offset?

 Please tell me the calculation formula if possible.

Please let me know if there is a calculation formula or reference document for the total error of the accelerometer.

Best regards,

T-yoshi

  • 0
    •  Analog Employees 
    on Sep 10, 2021 3:14 PM

    Hi T-yoshi, 

    Q1: Does "Initial 0 g Output" mean the same as offset? Yes

    Q2. What is the difference between "0 g Output Drift over Temperature" and "0 g Offset Tempco" in the table above?  the 0 g Offset Tempco parameter provides a typical value only. if you add offset + offset_tempco x ΔT we guarantee that value will not exceed the 0 g Output Drift over Temperature min and max limits. 

    Q3.How does the Initial alignment error affect sensitivity and offset? Can you clarify what do you mean with initial alignment error? Do you mean alignment of your calibration set up? 

    I hope this helps, 

    Pablo.  

  • Hi Pablo-san,

    Thank you for your support.

    Q3.How does the Initial alignment error affect sensitivity and offset? 

    Can you clarify what do you mean with initial alignment error? Do you mean alignment of your calibration set up? 

    Sorry, I made a mistake.

    What I wanted to say is Interaxis Alignment Error.

    I don't understand how this affects offset and sensitivity.

    Is this effect included in the offset above?

    I would like to know if it is necessary to consider this effect separately from the offset and sensitivity error.

    Best regards,

    T-yoshi

  • Hi Pablo-san,

    Any update on this issue?

    I would like to estimate total error in measurement.

    Please let me know if there are other items to consider.

    Best regards,

    T-yoshi

  • 0
    •  Analog Employees 
    on Sep 15, 2021 4:09 PM in reply to T_yoshi

    Hi yoshi-san, 

    sorry for the delay on my response. 

    If am not mistaken, the Interaxis Alignment Error parameter describes mechanical misalignment of the sensor die to the package, which is the main source of cross-axis sensitivity error. So by compensating for cross axis sensitivity you are already accounting for the interaxis alignment error. 

    Let me know if this helps, 

    Pablo.