Continuous sampling issue

[nasko1]

I am having an issue when indicating my rate for samples while using Labview with an accelerometer (in acquistion mode: continuous). For example: I indicate a rate of 1000hz which should output 1000 samples in one second. However, when I export to excel, the number of samples per second is 2000. It seems like the data is being collected twice as fast. Also, my read rate is set to be the same as my rate. Any advice would be much appreciated. Thank you!

[NIquist]

Post your code...

[nasko1]

[nasko1]

To further clarify - th excel output always has a delta x of .0005, regardless of what I change my rate to for the time settings. How do I make Labview output the frequency I specify?

[Dennis_Knutson]

You are doing something wrong and that is why you were asked to attach your program. Since you did not, run one of the examples that come with LabVIEW and compare.

[nasko1]

Attached is the VI.

[Dennis_Knutson · Accepted solution]

Now I can see that you are using cDAQ. If it is the 9234, the minimum sampling rate as you can see in the specs is 1.652 kS/s.

[crossrulz]

What modules are you using?  I think Dennis might be on to something.

[nasko1]

You guys are exactly right. I am using the 9233 which has a minimum sampling rate of 2 kS/s.Thank you for the advice.

Follow up question: A sample every .0005 seconds is a bit much, can I limit recording of the data?- I am thining I could use an elapsed time VI.

[crossrulz]

If you have the Full Development System, there's the Resample Waveform VI.  It is found in the Signal Processing->Waveform Conditioning pallet.