ADXL103/ADXL203 0 g Offset Long Term Drift

Hello Ivan,

I have a secondary reference, which might be helpful for you.  The ADIS16362 uses the ADXL203.  While this parameter naming convention has changed, the "Initial Bias" parameter for the Accelerometer, in the ADIS16362 datasheet incorporates a wide range of accelerated aging test observations.  We don't typically share the individual test data, but can offer that HTOL, temperature hysteresis, temperature cycling observations all contribute to this estimate.  In the ADIS16362, this parameter is +/-6mg, 1-sigma. 

http://www.analog.com/media/en/technical-documentation/data-sheets/ADIS16362.pdf

Hope that helps!

NevadaMark

Hi NevadaMark,

Thank you for pointing out to the ADIS16362 which is helpful.

ADIS16362 accelerometer typical In-Run Bias Stability is equal to 41 ug (1 sigma). 3 sigma gives 123 ug. But I observed 41-84 mV (or 41-84 mg) 0 g offset on ADXL103 after 1-2 months. Could it be true? Would you observed such difference in accelerometer's In-Run Bias Stability before? How frequently should I compensate 0 g offset for getting 41 ug In-Run Bias Stability?

Regards,

Ivan

Thank you for offering this observation but I have never seen an ADXL203 approach that level of drift.  Could you offer a more detailed explanation of your test approach and in particular, the method you are using to validate the repeatability of your observation method? 

Also, in my initial response to your question, I offered that the Initial Bias error was the parameter that includes the long-term drift expectations. Why are you using the In-run bias stability as your expectation for long-term drift?

Hi NevadaMark,

Thank you for the reply.

I thought that Initial Bias Error would be used for part to part initial offset variations and In-Run Bias Stability would be used for single part long-term drift.

Is it correct that Initial Bias Error includes not only 0 g initial offset part-to-part variations but also single part long-term drift?

How did you calculated In-Run Bias Stability for ADIS16362?

Thank you in advance.

Regards,

Ivan

Hi NevadaMark,

Thank you a lot for the detailed explanation. It is very helpful.

Regards,

Ivan

Hi Ivan,

I can see how this might be a little confusing but the key piece of information is that Initial Bias Error on the ADIS16362 is the same as Bias Repeatability on the ADIS16485, which provides a bit more information on what this parameter really means through a key footnote:

In-run bias stability comes from the minimum point on the Allan Variance curve.

This link might be useful for Allan Variance characterization at a specific integration time:

FAQ: Gyroscope In-Run Bias Stability