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98% duty cycle on NI myDAQ using LabVIEW?

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I'm trying to output a square wave with frequency 100Hz and a duty cycle of 98% but when I do this with labview I just read a flat 5v's and don't see any edges. I can output the square wave using NI ELVIS(and having it work) so I figure it should be doable with labview. Any sudjestions on how to make this work would be great thanks. I will atach my vi file.

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Message 1 of 11
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Your attached VI shows a DAQ Assistant with no input device wired.  Are you not using the NI ELVISmx library for your myDAQ device?

 

Bob Schor

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Message 2 of 11
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Uhmmmmm...Smiley Embarassed

you have a 1000 sample per second task with 100 samples being written.

 

Lets just check this box and make it a bit simpler:

Capture.PNG


"Should be" isn't "Is" -Jay
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Message 3 of 11
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Alright I have the box checked now.

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Message 4 of 11
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I'm using an external oscilloscope to measure the output and I belive I'm using the NI ELVIS mx libary.

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Message 5 of 11
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When you enter the duty cycle, be sure and enter it as 0.98, not 98.  You can add a Waveform Graph indicator and you can see what the signal out should look like.

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Message 6 of 11
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Alright I tried the .98 and put it on the graph this is what I get.

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Message 7 of 11
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If this would be easyier to do using a digital output I would be open to that method aswell.

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Message 8 of 11
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Something is clearly wrong.  What happens if you use 0.5 and 50?  Do either of them look like 50%?  If so, that tells you where the decimal point goes.  Then you can try 75%, 85%, 90% to see where it breaks down.  When you have the answers, post them, along with your current code (please post the VI, not a picture).

 

Bob Schor

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Message 9 of 11
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Okay so I have something that appears to work but I feel as theres probably a more elegent way of preforming it 

2ms edge.png

here is the output.

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Message 10 of 11
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