NI 9233 Impact hammer software trigger

[StuMtu]

I am collecting data of a Cantilever beam. I have setup the labview impact test module to acquire data with fmax 1200Hz, sampling frequency - 3000Hz, to acquire a data for about 0.9 secs with frequency resolution = 1.2Hz.
It shows me the impact when i run the software but does not collect or store data. Eventually an error is displayed saying software trigger has timed out. Also I have set the number of samples to 2500 but i am getting a message that the samples need to be more than 0 which I cannot understand.
   How am I suppose to collect data for one impact at a time and average it? I tried the N samples and run once options.

If you could help me out with this it would be great. Thanks a lot.

[tnek]

Hi StuMtu,

I noticed that this question is pretty much the same one as you posted on this thread. Let's continue on this thread since you are probably using the Sound and Vibration Assistant. I have copied my post from before.

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I was wondering if you could provide a little more information about the program that you are using. I am not quite sure what you are refering towhen you mention the "labview impact test module". Do you mean the impact test examples for LabVIEW or the Sound and Vibration Assistant? If you could clarify what you are using by posting the example or file that you are using, it would be a great help.

Normally, the way to prevent the timeout error for a trigger is to set the timeout to a longer period or ensure that you will receive a trigger within the given timeout. The should be a control for this property in the software trigger function you are using. You many also want to check that the level of your trigger is set correctly.

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Regards,

Kent

Applications Engineer 

[StuMtu]

I was wondering if you could provide a little more information about the program that you are using. I am not quite sure what you are refering towhen you mention the "labview impact test module". Do you mean the impact test examples for LabVIEW or the Sound and Vibration Assistant? If you could clarify what you are using by posting the example or file that you are using, it would be a great help.

Normally, the way to prevent the timeout error for a trigger is to set the timeout to a longer period or ensure that you will receive a trigger within the given timeout. The should be a control for this property in the software trigger function you are using. You many also want to check that the level of your trigger is set correctly.

Hello,

  I am using the Sound and Vibration Assistant. The impact hammer example that I am using was located in the Sound and Vibration Examples. I will try and post the example and the changes made to it as per my needs. I have set the trigger to 10 seconds. the impact hammer event and vibration data that I need to collect is only about a second long.

  The trigger level has been set to 0.001 ie 1m in the trigger level field. I am using RMS averaging mode with 10 averages. An error suggesting that the number of samples should be greater than zero too pops up.

Thank you very much for your help.

[StuMtu]

Hello Kent,

Attached is the sound and vibration assistant file which I am using to carry out the testing. I am usign Sound and Vibration Assistant along with NI 9233 cRIO USB module.

[StuMtu]

I have a new version so please ignore the previous attachment and consider the one attached to this post

[tnek · Accepted solution]

Hi StuMtu,

The two properties to set to clear the errors will be to increase the timeout in the configuration tab of the Trigger step. You must also ensure that you will be exciting the hammer above the set level within that timeout or else you will get the timeout error. 

The other error that you are receiving should just occur when you try to set the number of samples to averageto zero. If you set a number higher than that, the error should go away. If this still does not work, you can try placing a new step with the proper settings to see if the error still appears.

Regards,

Kent

Applications Engineer

[StuMtu]

Hello,

      I have got the trigger and sampling problems resolved with your help. Now, I am seeing a lot of noise in my measurements. I am using RMS averaging wtih 20 averages. The sampling rate is 2900 Hz and 5000 samples. The coherence shows value of almost one. How do I get rid of the noise? The impact hammer spectrum looks good to about 900Hz which is the range of interest. I will attach the Sound and Vibration assistant example I am using as soon as possible.

Thank you very much.

[Corby_B]

Hello StuMtu,

Thanks for your post back!

I see you are only doing 20 averages. You could perform more averages which could reduce the coherence of the signal you are measuring. If you can post a screen shot of your code this would be most helpful. Thanks and we hope to hear back from you soon!

Cheers!

Corby_B

http://www.ni.com/support 

[Adrian_rr83]

Hello

I'm using the Impact test to perform a modal analysis of a shaft with several discs. I would like to extract the data from this VI into a UFF file. I need this format file to be used in a third-party modal analysis software. Does anyone have any suggestion?

Cheers.

[enderWiggin10]

Hi Adrian,

In order to save in the UFF58 File Format, you will need to use the tools within the Sound and Vibration Measurement Suite.  This package will allow you to directly acquire data from a National Instruments device and save the data to the UFF File Format.

Best,