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How I can trigger on falling and on rising slope?

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Hi,

 

I have this attacked VI and want to trigger on rising and falling slope. How I can add both? Right now I am only able to choose between rising and falling, but I want to have both so that it triggers whenever the slope rises and also trigger when the slope falls.

 

I am also getting the Error 2000777 about Start.TrigType. What does this error mean ?

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Most DAQ cards can only trigger on one edge, not both.  It is a hardware limitation.  I have recently heard of some new DAQ card that has the ability to trigger on both edges.  However, I'm not sure what the model number is.  Perhaps you can check with your local NI rep.

- tbob

Inventor of the WORM Global
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Well, I just found this link that shows how to trigger on both edges.  One method involves using two counters.  The other requires the DAQ card I mentioned but didn't know the model number of, the NI 653x.

- tbob

Inventor of the WORM Global
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Ok, thanks I have the NI 6221 (37 pin) PCI card. Can you tell me something about the Error 200077 I am getting?

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I don't have that card.  You can always see what the error means by using the error out function wired to the error wire.  In the error out box, the string indicator tells you what the error is.  You can also right click on the error code box and select Explain Error.

 

- tbob

Inventor of the WORM Global
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The written VI is not working with my device NI 6221 (37 pin). Anybody knows why is it not working with my device. I think the device supports HW triggering but I still get the 200077 error

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Solution
Accepted by topic author blade2008

Please replace the Error Handler function at the end of your code with an Error Out function.  That way you can read the error for yourself.  I didn't memorize all the error codes.

 

You can put probes on all of the error wires to see where the error is occuring.  The error probably has something to do with some setup not being available for your particular card.

- tbob

Inventor of the WORM Global
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Thanks tbob 🙂

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