Acceleration in the Frequency Domain

[wisjaf12]

Hello

I am attaching a vi that I have already modified from an existing example. I will use this vi to measure pressure (from a pressure transducer) and acceleration (from an IEPE accelerometer). Each of the two sensors is connected into a C Series module housed in a 4 slot CompactDAQ Chassis. The pressure transducer will measure the pressure of water flowing in a pipeline while the accelerometer will simultaneously measure the vibration of that pipeline caused by the water pressure fluctuation. In this vi, I am logging both pressure and acceleration signal into a TDMS file and then reading both signals on separate waveform charts. The acceleration signal is written and read in the time domain. I need your help to perform more modification on this vi to take the acceleration signal and read it on a seperate chart in the Frequency domain and also write the frequency domain values into a TDMS file. After performing this modification, the vi is supposed to have three wave form charts (pressure, acceleration in time domain, and acceleration in frequency domain, and opens two tdms files, one for pressure and acceleration in time domain, and one for acceleration in frequency domain. 

I tried many ways all failed since I am not very familiar with vibration measurements.

Thank in advance.

[Trevor-B · Accepted solution]

Hi,

One important thing you need to decide is if the frequency data you are interested in is constant with respect to time, or if you need to know how the frequency data changes over time. 

For constant frequencies with respect to time, take a look at the Fast Fourier Transform: https://www.ni.com/en/shop/labview/using-fast-fourier-transforms-and-power-spectra-in-labview.html

If you need to know how the frequency chage, take a look at Joint Time Frequency Analysis: https://www.ni.com/en/shop/labview/joint-time-frequency-analysis--jtfa--overview.html

[wisjaf12]

Thank you