how to use 2 digital cameras by one serial port

[andisheye20]

hello every one

I have 2 digital camera model microsoft lifecam , I connect these 2 cameras by one serial port(usb serial hub), but when I want to use simeltansely these 2 camrea .it shows erors .

when i use them seprately they works and no problem accure.

I use these cameras for 3D positioning

[Bob_Schor]

Without seeing the code (meaning the VIs, not a picture of part of the block diagram), it is difficult to pinpoint your problem.  We've had 24 video cameras running simultaneously, recording behavioral experiments (but they were using TCP/IP, not USB).  Other than the problem of overloading the USB port (which you might be able to solve by not using a hub, but rather plugging into two USB inputs on your PC), I don't know why you'd have a problem ...

Bob ("If it's not Software, it's probably Hardware") Schor

[ijustlovemath]

Bob,

The USB standard is rated to daisy-chain up to 127 serial devices to a single port, and provided your hubs are of decent make and your devices are properly powered, you should see all of them. I have an application that uses VISA over 24 distinct devices, where the main hub uses just one port on the host computer. It sees everything just fine.

To the OP, it's possible your devices aren't powered enough. You should try a powered hub and report back. Code is also nice.

[Bob_Schor]

I agree that you should be able to put multiple USB cameras on a hub.  I also know (from my own experience) that it is possible to have 24 cameras running simultaneously.  Assuming that the unseen software is reasonable (a big assumption), I raised the possibility that his hardware setup might be checked ...

There is more we don't know about the Original Poster's setup and problem, so we are all guessing, at this point ...

Bob Schor

P.S. -- at one point, we tried our multi-camera setup with inexpensive USB cameras (I don't remember how we got the cameras to "talk to" the PC -- I think there was another interface in between).  This was several years ago, before USB 3 cameras were widely available, but I recall we had trouble with 6 cameras ...

[billko]

What errors?  My car doesn't run right either.  Can you fix it for me?

I remember something about some camera models all have the same serial number and appear to be the same device to USB.