Multiple IMAQdx USB camera acquisitions simultaneously

[fblerg]

Hi Abhijit,

Just to close the loop, I believe that you are not able to acquire from both cameras simultaneously because of driver issues with the ELP USB cameras. Per the below KB, since the IMAQdx driver goes through the camera driver, if the camera driver is unable to acquire from multiple cameras simultaneously, then IMAQdx will not be able to acquire from these cameras simultaneously.  You will have to Open -> Acquire -> Close from each camera in a loop to acquire from each separately. I would recommend upgrading to USB3 if you need a higher frame rate. 

Can I Acquire From Multiple USB Cameras Simultaneously Using IMAQdx?

http://digital.ni.com/public.nsf/allkb/D13527D8471D5FC5862576A4006BD081

[Bob_Schor]

Finally!  I found a bug (for which NI has filed a CAR) that causes LabVIEW 2014 SP1 and LabVIEW 2015 to install the Vision software, but not to activate it (or tell you to activate it), leaving you without the IMAQdx functions.  Fixed it, and wrote the attached routine that acquires images from two Web Cams simultaneously.  One is a Logitech HD Pro WebCam 920, the other is a Microsoft LifeCam.  I believe both are USB 2.0.

So the answer is, Yes, it is possible.  There may be some camera/USB Port restrictions, but here on this machine, it works ...

Bob Schor

[abhi_vt]

Hi Bob,

That's great news! However, unfortunately, I have LabVIEW 2010 and NI-IMAQdx 3.7 so I was not able to open the code you attached. Is there any chance that you could take a screen shot of the back panel of the VI so that I can try to replicate your code?

Thanks

[Bob_Schor · Accepted solution]

My apologies!  Here is a Snippet ...  I'll point out that this didn't work until I had all four loops running in parallel ...  I also tried this at work, where I plugged another Logitech camera (several years older than the 920) in and my USB driver was only able to handle one of them (but I gather this is not your problem).

Bob Schor

[wekro]

Hello,

 I acquire with 3 Firewire cameras in grab mode with IMAQdx.

The main problem was the start of the initiallisation of the cameras.

When using this structur no error occurs.

[Trythis]

Can you share your vi code pls?