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How to use a pretrigger to obtain data on three channels before triggering an event

I've got a USB 6009 DAQ and I'm collecting three channels of data on the analog inputs. Also, I'm using both analog outputs to control two external devices. I'm trying to figure out how to program a "pre-trigger" into the program so I can collect data but not start the trigger until I say it's time. I've made a simple diagram of the way I'm trying to make it. See the attached picture. I've tried to make it as clear as possible but I know that doesn't always happen. Let me know if it's not clear to you. Thanks

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Hi aparker,

 

The following documents should be able to help you out. Thanks!

 

Analog Acquisition with Software Analog Reference Trigger: https://decibel.ni.com/content/docs/DOC-5583

Software Analog Trigger with Pre-Trigger Samples: https://decibel.ni.com/content/docs/DOC-6565

Synchronized Analog Input/Ouput with an Analog Trigger and Pre-Triggered Samples: https://decibel.ni.com/content/docs/DOC-8264

 

-Carisa

Applications Engineer
National Instruments
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Thanks for the links. Is there some way that I can manually control the trigger rather than using a predefined input to control it?

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Hi aparker,

 

Let's assume that you're looking at Synchronized Analog Input/Ouput with an Analog Trigger and Pre-Triggered Samples: https://decibel.ni.com/content/docs/DOC-8264

 

You can see that the source of the Start Digital Edge Trigger is ai/ReferenceTrigger, which is a constant. This can be changed to be a control instead if you delete the current input source wire and then right-click on the source input and create a control. I've included a screenshot. Hope this helps!

 

Best,

Carisa

 

Applications Engineer
National Instruments
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