AnsweredAssumed Answered

LIS3DH 5kHz ODR not possible

Question asked by schulz.markus on May 9, 2016
Latest reply on Aug 15, 2017 by Miroslav B
Hello all,
I want to use the LIS3DH accelerometer and a Steval-MK1109v2 Motherboard with the ST Unico GUI for logging Acceleration data.
The datasheet of the LIS3DH shows the possibility to meassure a bandwidth up to 5000Hz, which i need for my shaker meassurements.

I used the Unico GUI to configure the Sensor at +-2g and the 5000Hz mode.
I tried a 160Hz sine signal at the shaker and made an online FFT at the Unico GUI, but there was shown a peak at about ~600Hz, so i took a look at the logged data in the .txt-file. I wanted to add a timepath but recognised that the number of the lines weren´t right at all.
I logged data at about 3 seconds but got only roundabout 4000 lines. With a ODR of 5000Hz i expected up to 16000 lines.

I tested the modes with 400Hz and 1250Hz and both online-FFT an logged data were right.
If I use the 0.0008s timesteps (1/1250Hz) for the logged 5000Hz-mode before, it looks right...  

So theres my question:
Does the Unico GUI only logg data with a rate up to 1250Hz(even in the 5000Hz mode) or could it be a bug in the Unico GUI software? 
If I take a look on the wrong online FFT of the GUI, where 600Hz are shown but surely only a 160Hz-signal is given, it looks like that.

Im a little confused.

Thanks for your help!

Greetings,
Markus Schulz

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