Problem with MMA8452Q when rotating above 600 RPM

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Problem with MMA8452Q when rotating above 600 RPM

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anthonys
Contributor I

Hey there,

I'm trying to measure the frequency of a blade rotating with an MMA8452Q, and am having a strange issue where it is filtering out my data once the speed reaches 10 RPS (600 RPM). Here is a graph of the data in question:

acc1.png

Sorry it's such a horrendous graph, my graphing tools aren't very good. The x axis is tangential to the centre of rotation and is blue, the y axis is normal to the centre of rotation and is pink, and the z axis is pointing out of the plane of the blades and is yellow.

My primary concern is the patch where the y axis suddenly jumps up to 0.5g and the x axis attenuates. This is when the blades are rotating at >10 RPS. Is there some kind of low-pass filter that could be causing this? I just can't understand why the x axis is attenuating so much.

Thank you for any help you can provide. It might also be worth noting that when the speed is >10 RPS, the acceleration in the y direction is about 50g. I am expecting that to clip, and am happy for it to, I just want to read the x axis data.

Cheers,

Anthony

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reyes
NXP TechSupport
NXP TechSupport

Hi Anthony Stancombe,

Unfortunately we cannot warranty the correct behavior of the accelerometer at forces beyond the measurement range. There are not specs characterized for forces beyond these forces, so we cannot know how will the the behavior of the device.


Have a great day,
Jose Reyes

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