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simultaneous image aquisition using identical usb cameras
Solved!
TH81
08-23-2011 10:10 AM - edited 08-23-2011 10:13 AM
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Hello LV Users,
I have put together a vi (probably not the best programming skills, its only my second vi) to simultaneously aquire images from two usb cameras using LV2010 32bit + VAS 2010. As long as the two cameras are different there is absolutely no trouble. This changes once I use identical devices. Then it works well on my win7 64bit machine, but does not work once I create an application. Also when transferring to a different machine with winXP 32bit it does not work at all. Does anyone have an idea why?
My thoughts are that maybe there are different version of direct show installed (I will check) or the drivers for the cams (DNT DigiMicro 2.0 Scale) work different on the two Systems.
Two more thing are to mention: first: LV resolves the cameras on two different IDs (cam0 and cam2, as it happens), but when using xp one cannot be configured (IMAQdx configure grab VI)
second: The cam-sessions are not always closed correctly, usb channel remains open, which lead to trouble with the IMAQdx configure grad.VI in the next run.
attched is my VI. If there are some thoughts for improvement I'm happy for comments.
Thanks a lot,
Tobias
Solved! Go to Solution.
Meadow
08-24-2011 02:01 AM
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Hi Tobias,
I think you are forgot to attached your VI in your previous post.
Regards
LabVIEW 7.0 - 2011, Vision, RT, FPGA
TestStand 3.0 - 4.5
08-24-2011 02:32 AM
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You are quite right, thanks for mentioning
here it is.
regards
08-24-2011 03:07 AM
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Update,
it seems to me that it is a issue of operating system. I have now tried the VI on Win7 32bit and there is no problem at all.
Tobias
jtagg
08-25-2011 04:09 AM
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Hi,
I agree that the problem seems to be OS related. It seems that XP has a harder time differentiating between the cameras when working with Measurement and Automation Explorer than Windows 7.
Some USB camera drivers simply don't allow doing that and it could be that the xp driver is not as advanced as the Windows 7 driver.
Here is a link about the issue:
http://digital.ni.com/public.nsf/allkb/D13527D8471D5FC5862576A4006BD081?OpenDocument
Hope this helps.
Regards,
joseph Tagg
