USB3 Vision on cRIO 9035 USB2 ports

[krishnaLafayette]

I am considering using a Basler Ace ac640-750um camera for a machine vision application run by a cRIO 9035 operating on Linux RT. According to NI information, the cRIO-9035 is capable of operating any USB3 Vision camera as long as it is backwards compatible with the USB2 standard. However, I am concerned about a bottleneck being imposed upon data transfer speeds by the limits of the cRIO's USB2 bus. 

This application requires continuous rapid acquisition and processing, making the ac640-750um an ideal camera (~750 fps) that could potentially outperform its GigE counterparts. However, if the data throughput is severely limited, the high frame rate will be useless.

Does anyone have any experience operating a USB3 camera over a USB2 cRIO bus, particularly for high fps acquisition? How significant is the effect on throughput and effective frame rate? Finally, is there a cRIO module with USB3 input buses available? I have looked but not seen any. 

Thanks

[BruceAmmons]

When plugged in to the cRIO USB2 port, the camera will run at USB2 speeds.  I think the max speed ends up right around 60 fps, but I could be off a little.  You won't be anywhere close to 750 fps.  For speeds like that on a cRIO you will have to use GigE.

Remember the processor on a cRIO is quite a bit slower than a PC processor.  You can max it out very quickly with intensive vision analysis.

I have used a USB3 camera on a PC to achieve high frame rates with success.  Just remember you have to keep the analysis very simple to be able to analyze every image.  You would only have about 1 msec to analyze each image, and you can't do much in that time.

Bruce

[kensign]

I agree with Bruce that your throughput will be dramatically limited by what is allowable at USB 2.0. Regarding your question about whether other cRIO models have USB3 ports, the newest ones do such as https://www.ni.com/en-us/shop/model/crio-9045.html.

Edit: found a more helpful link that lists out all supported real-time targets with USB 3.0/3.1 ports -- https://www.ni.com/en/support/documentation/supplemental/16/usb3-vision-cameras-and-ni-real-time-tar...

Hope this helps,

Katie