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How do I synchronize two PXI 5922 using TClk while using a Software Reference Trigger?

Hi all,

I am trying to synchronize two PXI 5922s (in the same PXI chassis) using TClk.

I have set up the Master Session to receive a Software Reference Trigger, and I want the Fetch vis to fetch data relative to the Software Reference Trigger. I did not configure a trigger for the slave session, so that the trigger from the master session will be exported to the slave session.


However, when I run my program (see attached screenshot 1), the Fetch vis will time out.


If I remove the Software Trigger (both configuration and the actual sending of the trigger, see screenshot 2), the Fetch vis will fetch data, and the program exits without an error. I suppose that is because Immediate Triggering kicks in? Are the boards really synchronized in this case?


What am I doing wrong?


Thanks for your help!

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Message 1 of 5

Hi tbartsch,


One of the advantages of using NI-TClk is that it automatically configures the slave sessions to receive start triggers from the master. That means that there is no need to add the VI for the configuration of your software trigger.

Efrain G.
National Instruments
Visit for step-by-step help in setting up your system.
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Message 2 of 5

Hi Efrain,


thanks for the reply!

I'm not configuring the slave session to receive a trigger. If you look at the screenshots, only the Master session is set up that way.

I'm still very confused as to what I am doing wrong. Any help would be much appreciated!



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Message 3 of 5

Hi tobias,


If you compare your code with the example that I have attached here, you will see that you are missing the Configure Trigger Window VI to configure the trigger for your Master device. Therefore, your acquisition uses "immediate triggering" by default.

Efrain G.
National Instruments
Visit for step-by-step help in setting up your system.
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Message 4 of 5

Hi Efrain!


The "Software Ref Trigger" vi that I used is another instance of the vi you mentioned ("Configure Trigger Window vi"). Therefore, I believe that the acquisition should not be defaulting to immediate triggering. 

Do I have to call both instances of this vi? Isn't "Configure Trigger Window vi" only meant for triggering by analog signals, and NOT for triggering by a Software Trigger?





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Message 5 of 5