Real-Time Measurement and Control

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Connect a USB-6251 M Series DAQ to cRIO-9040

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I have a USB-6251 that I want to incorporate into my measurement setup and I also have a cRIO 9040, which does most of my measurements. I see that cRIO computer has a USB-port. Is cRIO capable of talking to USB-6251 via USB? 

Thanks a lot in advance

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Message 1 of 8
Accepted by topic author brimkins

Hi Brimkins,


This is definitely an interesting question. Unfortunately, there's one simple answer of no, connecting a USB-DAQ isn't a supported configuration with a cRIO controller.

There's a quick list of what USB devices are supported on Real-Time targets at the end of this KB.


For the cRIO-9040, you're looking at having the ability to use some cDAQ, cRIO, CVS or industrial controllers as it's running Linux RT. Otherwise, the drivers for the USB-DAQ aren't developed for Linux RT.


Can I ask what the use-case of this is? The cRIO is deterministic and USB isn't a deterministic interface, so I expect you'd see a significant degradation in performance than just attaching another C-series module. Is there a reason we don't want to use a C-Series module with better performance?


Best wishes,


Message 2 of 8

Dear Nick, 


thanks for your reply,

it was just a temporary solution until I will get an NI 9361 module to do the counting. I have also found that I can do counting with DAQmx in cRIO with a clock up to 80MHz. I think that will be my solution for now. Unfortunately counting with 40MHz FPGA clock is too slow for the pulses that I am trying to count. 


Best regards,


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Message 3 of 8

Hi Sergii,


No worries.

Have you seen the FPGA Derived Clock Properties? You should be able to generate a suitable clock to use on the FPGA. 

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Message 4 of 8

Dear Nick, 

yes, I tried that, but the fastest clock it gives is the FPGA base clock which is 40MHz and perfectly allows my 12 ns pulses to slip out. Therefore I thought of using the DAQmx module for NI 9402 (then i can see a 80 MHz clock in the timing source). 



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Message 5 of 8

Hi Sergii,


Are you sure that 40MHz is the maximum? I added a cRIO-9040 to my project and I was able to derive an 80MHz clock:


Edit: Also able to derive other clocks, such as 85MHz. It seems you'd be able to fit your 12ns pulses.


Best wishes,


Message 6 of 8

Hi Nick, 

thanks a lot! Wow, I didn't know that I can use 80MHz clock to drive a single-cycle loop

I was considering this diagram from the manual 


but I was completely oblivious of this derived clocks. Thanks for pointing this out. I may get away without extra counting module!



PS SCTL would take 80 MHz as well as NI9402, but with 85MHz wouldn't compile

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Message 7 of 8

Actually I could get even 120MHz clock! Awesome! and NI9204 would take it.

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Message 8 of 8