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ADXRS646 Self Test

Hi

We are planning to use ADXRS646-EP in one of our products and I have the following questions about the Self-Test feature.

1) When ST1/ST2 is activated, what is the coverage of test performed? Does it test the mechanical bits of the MEMS gyro as well or does it only guarantee the integrity of the electrical interface?

2) How will the Rateout voltage be affected when ST1/ST2 is activated while the gyro is experiencing a yaw rate? For example, when the gyro is subjected to say 20°/s yaw rate and if I activate ST2, will the Rateout signal correspond to 50°/s yaw rate or (50+20=70)°/s yaw rate?

3) The parameters of this gyro (Null bias, stability) etc seem to vary significantly with temperature as well as between 1 unit to another. This is proving to be bit of challenge to get good accuracy without calibrating every unit that is manufactured. Can you suggest any other gyroscope with similar performance spec with better accuracy and less unit to unit variation?

Thanks

Nagendran

  • Hi Nagendran, 

    1) the ST feature performs a mechanical stimulus similar to the effect of the angular velocity. So it test the integrity of the mechanical structure of the MEMS sensor. 

    2) You are right, in the presence of a angular rate, the effect of ST will couple to the rateout signal. 

    3) I think the ADIS16135 gyro would work, based on your requirements.  

    I hope this helps, 

    Pablo