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About wiggie

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    LAVA groupie
  1. I'm having a problem with reading an input. The input is a 64 bit real 2-D array of double. I will refer to the attached screenshot. All other inputs, such as "all" (meaning all channels) and "trig" (trigger), I can read, no problem. The problem is I cannot read "chan", which is part of the array "all" (containing all channels), but referenced to a reference channel. If i dispaly the "chan" array in LV I can see it no problem, I can even read the size of it and display it. Why can't I use it in the MathScript node?
  2. Hi all, I created a list and I connected to some subvi, and the problem I have is that I cannot select any item on that list while not in edit mode. When I am in edit mode I can select any item without any problems. The way I created the list, is simply by adding it and editing the list items and connecting it to the subVi. I made sure that it is marked as "active" under properties. If I provided to little info on my problem, then please let me know. Here is a screenshot of the list. Cheers, Paul
  3. I have changed the multiplier on the Scale tab of the graph properties from 25 to 2. That made the difference. The data coming in to the graph has 256 samples, which is quite strange. I will play around with the program and see what else I find out. Right now I can see the 50 Hz peak at a value of 50, and that tells me that the frequency axis is correct. Thank you very much for your help, it's appreciated. Paul
  4. Thanks for answering Mike. Here are my answers to some of your questions; below you will find a screenshot of the graphs: The frequency graphs display on the x-axis the numbers from 0 to 6375 which does not correspond to the frequencies, because the sampling rate of the data is 1024 Hz, which would correspond to frequencies from 0 to 512 (if only half the data were plotted). Furthermore, since I am testing it using some EEG measurement apparatus, measuring nothing more than the 50 Hz buzz of the lamps, I should see the highest peak at 50 Hz and not at around 600. To make sure that my assumptions are correct, I wrote a short matlab script which plots an fft signal. I then loaded it into a mathscript node and let it run. You can see the result on the screenshot below. The 50 Hz are clearly present and also the 150 Hz and 250 Hz harmonics. I will have to check to see if the data is formatted correctly, but I am pretty sure that it is. Paul
  5. I've been using Labview for about 2.5 months. Right now I am working on an already available source code in order to change a few things for the measurements that we want to do. The problem I have is as follows: There is a signal in the time domain coming in, that is being transformed through an FFT to the frequency domain (in a for loop). When I plot the signal (in another for loop), the frequency axis is not being displayed properly. how can I make sure that the frequency axis is displayed properly? Here are screenshots of the block diagram with 1. the time domain plot and 2. the frequency domain plot.
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