How Do I perform a Live Update using property node for a IMAQ front panel indicator?

[Alias user name here]

Where are the examples for using the new property nodes? How does one instigate an update of the display - especially after ROI functions?

[BruceAmmons]

To do an update of a displayed image on the new front panel image display, you can use an Invoke Node and select Refresh Image.

Bruce

[Alias user name here]

Bruce,
I've heard that not all the property nodes work in vision 7.0 -such as the "Value" Property.

[BruceAmmons]

I'm not sure about any details regarding that, but I am pretty sure this Invoke Node works pretty well. I have used it several times.

Bruce

[Julie S]

It is true that the Value property will give an error if you try updating it in Vision 7.0 - this will be fixed in the next version of the software.
In the meantime, the workaround is to use a global variable to pass images from one VI to another instead of the property node. Using a global variable works, but not in the same way as a reference or property node would. With a reference or property node, you can pass a reference of the control to a subVI and have the subVI update the control's image. Using global variables, the subVI will update the global variable with the new images, but you need a loop monitoring the global variable in your top level VI.

Hope this helps-
Julie S
Applications Engineer
National Instruments

[Alias user name here]

Does the "Method Property - Update" Work? Could I not pass the IMAQ Image reference to the modifying vi - like draw ROI rectangle - then call the "refresh" method?

[Julie S]

Yes - that should work. The situation I was referring to was if you were trying to update an image from a subVI.