Trying to use two framegrabbers at once

[JKLambert]

I am trying to capture images from two different framegrabbers simultaneously and I have been partially successful. There is just one odd behavior that I don't understand. If I start acquisition on camera 1, then on camera 2, they both work and I can see both images in WindView windows just fine. The problem is, if I stop acquisition and exit the VI for camera 1, the camera 2 VI dies saying that the interface or session is invalid. It appears that stopping acquisition on my first camera somehow intereferes with the IMAQ session for the second camera. How can I avoid this problem?

[s_a_s]

Hello,

I'm not really sure what could be causing this behavior - there could be a number of things causing the problem.  A few questions for you and then we can see what we can do to get this problem fixed for you:


1. Which frame grabbers are you using and which version of the driver?
2. What cameras are you using?
3. Are you using any external connections between the cameras for synchronization? (Genlocking)
4. Are you able to run camera 2 without running camera 1 and if so, if you start camera 2 first does the same behavior occur? (ie error on camera 1 when you stop camera 2.)
5. Could you post a simplified version of your code that reproduces the error.

Looking forward to hearing back from you so we can get this solved.

[JKLambert]

The framegrabbers in question are the 1422 and the 1428. The cameras are custom designed and built for us. The two cameras are not syched together in the lab. I can start either camera's acquisition first -- if I stop whichever one I started first while the other is still acquiring, the error occurs. I have attached the two VIs that I'm using. They both used to have an IMAQ close at the end, but I removed them to see if that was the problem.

[s_a_s]

I just ran both of the examples with LabVIEW 8 and NI-IMAQ 3.5.1 and had no problems.  What versions of LabVIEW and IMAQ do you have?

[JKLambert]

We are running LabView 7.1; I'm not sure what version of IMAQ we currently have.

[s_a_s]

I just tried it out with LabVIEW 7.1 also, and it is working on my system.  Let's try upgrading you to the newest version of the drivers to see if that will fix the problem.  The current version of NI-IMAQ (3.5.1)  is now a part of the Vision Acquisition Software.  Here is a link to the driver.  Let me know if this helps:

http://digital.ni.com/softlib.nsf/websearch/34e35376a052690e862570f9005349a3

[JKLambert]

I am very reluctant to do that. The last time I upgraded my IMAQ software, our entire lab went down. There were many problems caused by that new version and I got in some trouble for upgrading it when there was really no reason to do so. Some of the bugs introduced were never able to be fixed by your technical support and we finally had to change the way we did certain things. We are currently using version 3.0.0. I just don't want to upgrade and have things break on us again.

[JKLambert]

Ok, I just installed IMAQ 3.5.0 from my February update CDs. I figured that would be easier than trying to download them -- we have to stand on our heads to FTP things here, it won't work from ftp:// hyperlinks. The new IMAQ drivers installed successfully. The installer, as always, erased all my .iid files from the NI-IMAQ/data directory (you should really think about fixing that particular foible) but I keep them backed up elsewhere. Once I put those back, all our applications seem to be working so far and the error condition no longer occurs.

[s_a_s]

I'm glad to hear that everything is working!  I also appreciate your feedback on improving our current upgrade process with our drivers.  We are always looking to improve our products and greatly appreciate any feedback we get when it comes to product suggestions.  The best means to get this (or any other feedback) to the proper people here is to go to www.ni.com and click on the gray "Contact NI" button at the top left of the page and then on the "Feedback" link on the bottom left of the next page.

Contact NI
http://sine.ni.com/apps/utf8/nicc.call_me