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Count Squares with 500Hz

Hi!
 
I've generated with the ExpressVI "Simulate Signal" a Square with the maximum frequency of 500Hz (it varies). Now I want to count the falling flanks.
I tried this with the "Trigger Counter.vi"-Example which I slightly changed for my purposes. (see attached file) But it seems as if the Counter is not fast enough for my Signal (- it counts too slow).
 
Does anybody have an idea how I can solve the problem and count the correct value of squares?
 
Shorty to my system: I tried it with a 2GHz Sempron with LabView8 
                                      and with a 1,3GHz Centrino with LabView7.1
 
Thank you in advance
  Hendrik

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Message 1 of 8
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Puplicate Dost, see here:

http://forums.ni.com/ni/board/message?board.id=40&message.id=3422

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"It’s the questions that drive us.”
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I know! I already asked the Admin to delete the post in the HardwareBoard.
I accidently posted it there first because it maches to the topic "Counter/Timer". But I'm looking for a software solution. So I posted it again in this board!
 
Sorry for unintentional spamming... 😞
 
I hope nevertheless that anybody has a solution for me...
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Hendrick
 
No problem, welcome to the forums happy smiley.
It's common to flag duplicate posts to prevent duplicate efforts at solving a problem. Thanks for asking the Admins to delete one.
I am sure some will be able to assit.
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"It’s the questions that drive us.”
~~~~~~~~~~~~~~~~~~~~~~~~~~
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If you have a simulated square wave waveform, you can count falling edges by simple emulating what a counter does, essentially for each poind threshold it.  If it is above some threshold it is a high value, and if it is below th it is low, use a shift register to compare sequential hi/low booleans.  Check for a high to low transition (if n-1 is high and n is low there is a falling edge) use another shift reg to count these events.  Do this for every point in the waveform.  If you have simulated a noisy signal, you can get more advanced usint techniques such as a schmitt trigger (hysterisis).

 

Paul

Paul Falkenstein
Coleman Technologies Inc.
CLA, CPI, AIA-Vision
Labview 4.0- 2013, RT, Vision, FPGA
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Thank you very much Paul, your solution is working fine and it is so easy that I'm a little bit ashamed that I posted that question!
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No problem, the answer always seems much easier once you have seen it.
 
Paul
Paul Falkenstein
Coleman Technologies Inc.
CLA, CPI, AIA-Vision
Labview 4.0- 2013, RT, Vision, FPGA
Message 7 of 8
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Do you have the trigger counter.vi? I don't have it in my examples.

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