Vision Builder 7.0(IMAQ) : Using fxs in subVIs with references to image control

[DonRoth]

When using IMAQ fxs (such as 'Write File') in subVIs, if one wanted to use references to an image control, what property or method would be used to feed into the image terminal in the imaq fx on the subVI? Is this possible?

What did work: I was able to directly use the image control on the main feeding an image control on the subvi panel (which is then fed directly to imaq fx)

What did not work: From a refnum control for the image on the main, I used (within the subVI) the value property fed to a 'Variant to Data' with type as image control, then feeding the output of this into imaq fx.

[dmp]

Typically you would update an Image Display control from a subVI using the Value property nodes. However, this method does not currently work with LabVIEW 7 and Vision 7, but the issue will be resolved in the next release of LabVIEW and Vision.

In the meantime, in addition to the solution you found you could also use a global variable to pass images from one VI to another. 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.

I hope this
helps! Best wishes.

Regards,
Dawna P.
Applications Engineer
National Instruments

[DonRoth]

Hello Dawna:

In fact, I had already implemented your 'global' alternative solution using a LabVIEW 2 style global and it worked fine. Thanks for the information that NI is addressing this.

Sincerely,

Don