I Need Help! Analyzing Frequency Components of Accelerometer Vibration

[Crispo]

---

Hummer1 wrote:

Here is a little background on sampling theory.

The faster you sample, the higher the resolution you get in the frequency domain when you do the FFT on the data.

http://en.wikipedia.org/wiki/Sampling_(signal_processing)

Hope this helps

Hummer1

---

I'm going through the link. Thanks for taking the time to post something which could help me.

Sincerely,

Jason

[jyang72211]

Hi Alterrock,

The write to spreadsheet takes either a 1D or 2D array.  If your extract tone function is givein you a cluster, you need to do a unbundle by name to extract the array inside the cluster.

Yik

[ssingh1]

Dear  Preston Johnson,

Can't we simply use "Basic DC/RMS" VI to find and remove DC value of the Accelerometer signal insted of using Median?

Is Finding Median a better option for removing DC from accelerometers?

Please clarify.

Message Edited by ssingh1 on 25-02-2010 12:58 PM

[411051]

Hello Preston,

I am using NI hardware : cDaq9174, module 9233 and an accelerometer (IRD make mil521)having sensitivity 100mv/g.

In the vi we are integrating the signal to get vel. & further disp.We calibrated the setup by taking the reading on motor pulley set up rotating at @1250 rpm

All three parameters Accln.,vel.,disp.were correct.When we increased the rpm the readings were wrong.

As operating freq. 0f 9233 module is @ 21kHz, can we select 20kHz sampling freq?

Pl. guide .

regards,

Sam

[KatieC]

Sam, 

Thank you for using NI forums! You can find the valid sampling rates for the 9233 here. As you can see, you can sample at 25 kS/s or 16.6667 kS/s, but not at exactly 20 kS/s. Hope that helps!

Katie

[411051]

Hello Katie,

Thank You very much for your suggestion. Now pl. guide about no. of samples to read using 9233. At present sampling rate is 25Ks/s and I am reading 10000 samples . Will it be O.K.