Up to how many USB Cam could connect to a cRIO at once?

[EpicJean]

Hi, Everyone

I would like to know up to how many USB cameras I can connect to a cRIO at once.

(In other words, how many cameras can a cRIO recognize)

I understand that a power source and a USB hub are required. 

So far I have tried to connect 4 cameras to cRIO 9035 and they all work fine. 

I might have to connect 10+ cameras to the cRIO

The data flow should be far lesser than 480MB/s which is the speed of USB2 since we won't have high resolution image.

My concern is that does a cRIO limit the number of cameras?

Thanks, 

[BlueCheese]

What type of camera are you using? The answer could vary depending on whether you are using UVC webcams or USB3 Vision cameras.

[EpicJean]

Currently we are using UVC webcams, but we might use USB3 cameras in the future

How many cameras could a cRIO recognize in both of the circumstances??

Thank you,

[BlueCheese · Accepted solution]

I am not aware of any fundamental limits to recognizing cameras of either type. There may be limits by the OS, but I can't imagine you'd hit that unless you're talking about hundreds of cameras.

The USB bus and controller does have some limitations, such as a maximum of 127 devices per root port (due to a 7-bit address USB uses), as well as a controller-specific limit to the number of endpoints used by all devices on the bus. This could limit you to perhaps ~30 cameras with 3 endpoints each (what USB3 Vision uses).

UVC has some additional limitations in that bandwidth is reserved isochronously, so at some point you will run out of slots in the bus cycle for more image streams. USB3 Vision uses a bulk transfer mechanism instead, so you just share bandwidth among as many devices as are on the bus.

[EpicJean]

Thanks a lots for the reply!

It sounds like more than enough than what we need!