how to express vibration in time domain

[irfan789]

hi

i am acquiring accelrometer values from the sound and vibration signal simulator box 

the values are some what like this 

x=2.54656.. y=2.23456....

i want to plot the values in the time domain and later i want to find the magnitude and the frequency ie., in frequency domain

how can i do that.. 

[Lennard.C]

Hi irfan789,

There is an example in NI Example Finder which you can look into. Go to LabVIEW >> Help >> Find Examples... >> Go to Search and type keyword "accelerometer". Presuming that you want to find the FFT value of your accelerometer readings, there is an example called: "Multifunction FFT (DAQmx).vi". You can refer to that code or other vis from the search. 

Or you can look into this link if you plan to use Express VIs: http://www.ni.com/white-paper/13042/en/

Hope that helps

Warmest regards,

Lennard.C

[preston_johnson]

Also consider the NI Sound and Vibration Measurement Suite, on-line HTML manual. It has concepts as well as function reference:

http://zone.ni.com/reference/en-XX/help/372416G-01/

[irfan789]

i have gone through few functions for performing FFT

i found two functions one is FFT point by point and other is FFT with signal 

i am getting a raw data from accelerometer which on shouldi use for determining harmonic analysis..

[Lennard.C]

Hi irfan789, 

Depends on how you want to analyze your data. Either you want to analyze the data point by point or you want to send in a batch of data (signal). Is your raw data in the form of 1D arrays or DBL?

Using Fast Fourier Transforms and Power Spectra in LabVIEW

http://www.ni.com/white-paper/4541/en/  

There are some additional examples in NI Example Finder like "Harmonic Analyzer Measurement.vi" and "FFT and Power Spectrum Units.vi" which you can refer to and see if that can assist you in your applications. 

Warmest regards,

Lennard.C

[Mashfique]

hello sir,

your question:-

Is your raw data in the form of 1D arrays or DBL?

  answer:- my data is DBL ..

So how should i proceed?

[Mashfique]

hello sir,

your question:-

Is your raw data in the form of 1D arrays or DBL?

  answer:- my data is DBL ..

So how should i proceed?

[Lennard.C]

Hi Mashfique,

Like I have mentioned to irfan789 that it depends on how you want to analyze the data. If you want to take a batch of data then analyze it to FFT, build array of a fix size and pass it to the FFT that takes signal as input. You can refer to the examples I have mentioned in my past post on how to pass an array of values to the FFT.

If you want to know the FFT of data point by point, then pass the DBL straight to that FFT but specify the length (default is 100 so you cannot pass the number of data less than 100). 

Warmest regards,

Lennard.C