Sampling Rate Control With Ni 9234 DAQ

[Vaelith]

I am trying to use the 9234 DAQ for a fourth year university design class to acquire accelerations in a wind turbine tower.
We are interested in trying to map the first few mode shapes, and as such need to measure at a low frequency range. As such,  we were planning a sampling frequency of around 200Hz, this would allow us to analyze frequencies as high as 100Hz, but we found out the 9234 daq will only go as low as 1652Hz. Due to wanting to map the entire length of the tower, we are using 24 accelerometers. However, sampling 24 channels at 1652 Hz for any long period of time (want to track vibrations for about 10 minutes) results in an extremely large amount of data. When transferring the data from labview to excel, the program would encounter a "Not enough memory" error and crash out. We wish to analyze the data using matlab and need to get the data from excel or a word file for analysis.

Is there any way to either override the sampling rate of the module, or create a labview program that uses an array to only send every xth data point to the excel file? I had never used labview before this year and don't really have any experience with programming in a labview environment.

Thanks for any help.

Vaelith

[Andrew.M]

Hi Vaelith,

Great questions. There is a LabVIEW function called Decimate 1D Array that can do exactly what you are looking for. Here is a help document that can give you some information on how it works:

NI LabVIEW Help: Decimate 1D Array Function

Also, if you are interested in learning more about LabVIEW, I strongly recommend checking out some of our tutorials. You can find those at NI Developer Zone: Tutorials 

Regards,

[Vaelith]

Thank you for your help. It worked perfectly, I  had to use a decimator for each channel, but at least now we can sample data for more than a couple of minutes.

Cheers,

Vaelith