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NI6289

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Hi everyone:

 

I want to use 2 USB 6289 to collect 30 chanel differential AI signal.

but due to one USB 6289 only has 16 AI channel. so that I must use 2 USB 6289 to acheive this application.

 

how do I know these 2 USB 6289 device delay time??

 

do you have this kind of experience before

 

br

 

vincent

 

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What do you mean by "device delay time?"

 

In general, I'd try to approach sync between different devices by sharing a sample clock.  Let device A be the master that exports its sample clock out to a PFI pin.  Device B will be the slave that imports its sample clock from a PFI pin.

 

You'll need to physically wire this sample clock signal between the two devices' respective PFI pins.  It'll probably be a good idea to run a physical wire beween their DGND pins too.

 

Then in your programming be sure to start the master task *last*.   That ought to do it.

 

 

-Kevin P

CAUTION! New LabVIEW adopters -- it's too late for me, but you *can* save yourself. The new subscription policy for LabVIEW puts NI's hand in your wallet for the rest of your working life. Are you sure you're *that* dedicated to LabVIEW? (Summary of my reasons in this post, part of a voluminous thread of mostly complaints starting here).
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Hi Kevin_P:

 

thanks for your response.

 

In my case, we have 2 USB 6289 then you suggest to use wire to connect device A PFI 0 and device B PFI 0.

 

Is it correct??

 

br

 

vincent

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Accepted by topic author vincent2615

Yes.  Then you'll also need to do the appropriate configuration in the tasks to export the signal from the "master" device/task to its PFI0 pin and then configure the "slave" device/task to get its sample clock signal from its own PFI0 pin.

 

Here's an idea of what some of that config might look like:

sync AI across USB devices.png

 

 

- Kevin P

CAUTION! New LabVIEW adopters -- it's too late for me, but you *can* save yourself. The new subscription policy for LabVIEW puts NI's hand in your wallet for the rest of your working life. Are you sure you're *that* dedicated to LabVIEW? (Summary of my reasons in this post, part of a voluminous thread of mostly complaints starting here).
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thx Kevin

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