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Trying to trigger a digital pulse from an analog edge

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I am trying to modify the simple "Generate Dig Pulse -Dig Start" example so that it triggers off an analog rising edge input. I have changed the trigger to analog edge and changed the trigger source and levels appropriately. However, I get a message wehn I try to run this that the only valid triggers are digital or none. I am trying to run this on a usb-6251.  Is this not possible? Is there a simple workaround? I cannot seem to find a simlar example. Thanks for your help.

analogtrigger.jpg

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Accepted by topic author MSF

Hi MSF,

 

It is possible for you to trigger a digital edge on an analog edge. However, you will have to do it a little bit differently than you current example does. I'd like for you to take a look at the Single Counter Pulse on Analog Edge Trigger with Continuous Acquisition example. You should be able to alter it to meet your digital generation and analog trigger needs. 

 

Regards,

Travis Ann

Customer Education Product Marketing Manager
National Instruments
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Thank you. By altering the timing on the digital pulse, I can indeed get this to work. I am curious. Is this a hardware limitation of the M series? Is it possible to directly trigger the pulse from an analog trigger on other devices?

 

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Hi MSF,

 

This is definitely a hardware limitation, but it isn't specific to just M-Series. You have to program this way for X and E-Series as well. 

 

Regards,

Travis Ann

Customer Education Product Marketing Manager
National Instruments
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Dear Sir

I have a question about this program, I want to generate a pulse at the falling edge of a sinewave signal. But in this program, these are two tasks. One is to acquire the sinewave signal, the other one is to generate a pulse. The question : the trigger of the second task is a digital edge start, and it need a Counter Trigger Source. Is there any relationship between this counter trigger source and the first task? How can I choose this trigger source if my device is PXIe-6356?

Thank you for your kind assistance!

Mr. Wu

HIT,China

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Hi Mr. Wu,

 

Generally it is better to create new forum posts when you have a question. This will give your post more visibility in the community. If you want to refer to a previous post, you can attach a link to the old post.

 

 

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