Q
How long does the ADXL345 take to recover from a high-shock overload before
it starts to operate normally?
A
If accelerometers are exposed to stimulus above the rated range they simply
saturate. The output goes as close to the appropriate rail as possible and
stays there as long as the over-range is present. Of course if you exceed the
absolute maximum shock rating (10,000g) then it may be possible to induce
physical damage, which would alter the performance of the device permanently.
The recovery time depends heavily on the shock profile, as well as on what
resonances exist in the mechanical system that may be excited by the shock.
The other thing is it’s impossible to tell, if an output isn’t looking like it
“should”, whether the accelerometer is somehow saturated, or whether it’s
faithfully reporting some motion that’s going on in the system. So not only is
it basically impossible to define any useful set of conditions, but it’s also
hard to make any meaningful measurement.
In summary, we are not able to provide waveforms describing shock recovery.
There is an infinite number of shock profiles and mechanical system resonances…
the best thing to do is address the behavior seen in the particular system.
