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ADXL1002 Accuracy Limitation

Hi engineer team,

 

I was looking on the ADXL1002 datasheet and I was wondering about something : is that significant and accurate to measure a voltage difference which is less than 2mV or 1mV with the ADXL1002 ? We know that the sensitivity is 40mV/g, and the ADXL1002 is made for a huge range +/-50g, so basically the main purpose is not to measure low variation.

I saw as well that the sensitivity due to the temperature is 5% of 40mV/g. So I assume than measuring an acceleration which is lower than 5% of 1g (which means 2mV) is not really accurate.

I am currently asking this cause we are reflecting about which ADC we are gonna use, and I am wondering if a 12bit ADC with a 4V VREF is enough (which allow us to have a resolution of 0.97mV).


Thanks for your help,

Florent

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  • Mark has it correct.  The ADC is typically recommended so that it will not limit the performance of the sensor.  The Sensitivity change over temperature will slightly change the output response over the temperature range, it does not suggest that vibration at low signal level cannot be observed. 

    Mark has done an excellent job at explaining the resolution impact on the combined performance.

    The noise floor and bandwidth of the ADXL1002 allows it produce response for low magnitude vibrations typically found in machine health monitoring.

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  • Mark has it correct.  The ADC is typically recommended so that it will not limit the performance of the sensor.  The Sensitivity change over temperature will slightly change the output response over the temperature range, it does not suggest that vibration at low signal level cannot be observed. 

    Mark has done an excellent job at explaining the resolution impact on the combined performance.

    The noise floor and bandwidth of the ADXL1002 allows it produce response for low magnitude vibrations typically found in machine health monitoring.

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