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What is the minimum output sample rate required for more accuracy data acquisition of  ADXL001-500BEZ ?

Question asked by ranga403 on Jul 1, 2018
Latest reply on Jul 3, 2018 by ranga403


         I have recently purchased ADXL001-500BEZ accelerometer for my device testing and i have observed some problems when I was trying to acquire the data from the accelerometer during the impact and  I was using mbed lpc1768 for ADC conversation and then store the values on my PC.


Case 1: When I try to read the output data with 1sample/ms, what I have observed is that I'm getting different values when I apply the same impact on the device. After few tests, I realized that I might be missing some data points between each sample which usually has shock value and then I switch the sample rate from 1sample/ms to 45samples/ms now I almost got the same results but I'm still not sure whether I'm missing some data points here also.


Please see the attached file of the response accelerometer in two cases where we can observe we might be missing some data points.

My ADC has limitation to exceed beyond that sample rate and now I want to know what will be minimum sample rate is required in order to retrieve all data points from accelerometer during impact without losing any peak value.


Case 2: Another problem is sometimes my output exceeds the output range i.e I'm getting value more than 500G. I have operated the device with 3.3v and connected as per the data sheet. [obtained output is 3.024 and the offset value of accelerometer at 0G is 1.625v with 3.3 voltage supply and its sensitivity is 2.2mv/G which result output shock=(3.024-1.625)/0.002=699.5G].  So can you please let me know what is the reason for this or it is the random value where impact value exceeds the accelerometer range.