Showing results for 
Search instead for 
Did you mean: 

Global Image Display Control Reference not happy

I'm trying to use a separate VI in parallel to the main Vi to display live video in an image display. I'd like to pass ROI and data information back to the main VI and I figure the control reference would be the easiest way. However, when I create a reference and change it to a control, then cut and paste it into a global variable VI, it gives an error saying that the control requires an external library that is not installed, is not installed to the correct location, or is not loadable, or the library's version is not high enough.

Any ideas what's going on or have other advice on how to accomplish my goal?
0 Kudos
Message 1 of 4
Maybe I should clarify the subject to elicit more response. Again, I'm trying to pass info from an Image Display in one VI to another and thought a global Image Display control reference would work great. Unfortunately, Image Display isn't one of the classes you can choose for a control reference type, and when you create a reference on the back panel of the vi and change it to a control, then cut and paste it into the global variable VI, it gives an error like above.

Hope someone can try it out and verify if they get the same behavior or if I have something installed incorrectly (no errors or anything amiss in the original software install process).
0 Kudos
Message 2 of 4
I'm not terribly familiar with the IMAQ product line, but is there any reason you can't just pass a copy of the image data itself in a global variable or single-element queue instead of trying to pass a reference to the image display indicator?
Jarrod S.
National Instruments
0 Kudos
Message 3 of 4
Other than the fact I don't like passing large amounts of data through a global variable (I think global variables should be used lightly if at all), I also need to get ROI information from the control as well. The only "method" of producing an ROI descriptor (for any VI that requires such) that I've seen in any example has been through a property node for a control. If this is the only way to get an ROI descriptor, then you have to pass a reference to the control if another VI is going to retrieve the ROI information and process it.

As a side note, the only other way of getting an ROI is with the IMAQ window VI "get ROI" but I want the user to be able to constantly change the ROI and not the dialogue behavior that the IMAQ window exhibits.
0 Kudos
Message 4 of 4