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peak detector

hello,
i hope u will got the idea what type of signal i want to display in the peak detector tab.
the signal of lvdt i have included in the txt file.
i do not know why the peak detector cannot read and display my result.
please help me to settle this problem and i am really really thankful.



regards,
mohd fauzul azim zin
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Message 11 of 15
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I still don't see any data on your front panel.  After you run it, you should see your data in the graphs.  Then do the menu Edit then Make Current Values default.  Then save the VI, this will allow everyone on the forums to see the data in the graphs as well.

Looking at your data file, there are 2 columns.  An X column going from 60 to 112.49 in increments of .01.  And a column for Dev2/AI5 which is nothing but zeroes the whole way down.  That is why you're not seeing any peaks.  Since the Write to Measurement file is working on the same data as the Peak Detector VI, it seems to me that the problem is in the data coming out of the DAQmx read.  And that data should show the problem in the Measurement Waveform chart.

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Message 12 of 15
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Hello,

I believe what is happening is a data type incompatability.  You are feeding the waveform directly into the peak detection vi, and I think that the vi is taking the wrong data out of the array.  Because the vi is looking for an array or numerics, I took the y values directly out of the waveform like this:



and fed those into the vi and it worked correctly.  I also modified the array I fed into the chart as well. I fed a sine wave into my input and got the following output:



I hope this is what you are looking for.  Please let me know if my description is not clear.


Message Edited by Neal M on 01-31-2008 03:19 PM
Neal M.
Applications Engineering       National Instruments        www.ni.com/support
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Message 13 of 15
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hello,
thanks for the lesson.
i have done the program, then i would like to try other peak detector which i can manage to scroll the plot legend for
the treshold. The input i get from the waveform but it seems like showing only a line and not a peak voltage.
why is that happen?
thanks


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Message 14 of 15
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Hi,

I assume you are referring to the "moveable" tab in your project, correct?  Does it seem from the array that the program is detecting the peaks, just not showing them on the graph? 

Jennifer R.
National Instruments
Applications Engineer
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Message 15 of 15
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