Property Nodes

[resrchengee]

I have created a vi which has an indicator that contains two property nodes. I am calling that vi from another vi.  I want the property nodes to be retained. For example, in the attached file I have an indicator from the sub vi. If you open the sub vi the string blinks when the code is run. However, the indicator on the main vi does not blink. Any help would be greatly appreciated.

[altenbach]

The property node points to the indicator of the subVI and has no relation at all to the indicator on the main VI. Property nodes don't go by label!

You need to create a reference the the indicator on the main VI and feed it to the subVI. Still, I don't know why you would need to set this property millions of times per second in a loop. Typically you shoud set properties only if the property changes.

See if this helps. 🙂

Message Edited by altenbach on 08-12-2007 02:14 PM

[resrchengee]

Thank you for the Reply. The idea here is to have a flashing string indicating that a certain action is happening. When that action has completed I will change the property node to false. I am going to have a case structure which activates that sub vi so it won't be happening all the time. Also, I have seen threads on here saying never to use references if you don't have to since it tends to slow things down? Is there no other way around that? Thanks for your help!

[mikeporter]

Given that the only purpose for this indicator is user feedback, performance shouldn't be an issue. Can you say a bit more about what you mean by a "flashing string"? Are you wanting to blink the text on and off, flash the background color, or something else? Also in this flashing display is there a sense that this display is a warning of some sort that needs to draw the operator's attention?

Mike...

[BillMe]

I think the spirit of those threads you mentioned is to use the data on the wires to drive your application where possible. There is nothing wrong with using references to do what you intend in your sub-VI.

[resrchengee]

Yes, exactly. The string will be a warning indicating to the user that something is happening. One, thing I am noticing however, is that once the  node property has been set and the vi. called once the string will blink the next time the vi runs even though I do not have true wired to the input of the case structure. See attached vi.

[mikeporter]

Yes, that is because property changes are persistent across stopping and restarting a VI. If you want it to be nonblinking until you press the button to make it start, you need to be sure to initialize the blinking property to FALSE when the top level VI starts.

Mike...

[resrchengee]

Yea, I figured that. I was hoping to make it invisable until it was called. Within the sub-vi I reset the property node to invisable after the sequence is complete. That lets the user know that its not happening anymore.  Problem is it would still be visable if user stops program before that sequence ended. I guess I could initialize it to invisable when program starts but you still see it for 100 ms or so :). Not very aesthetically appealing..

[mikeporter]

"Problem is it would still be visable if user stops program before that sequence ended."

So don't let them stop the program before the software has a chance to reinitialize everything.

Mike...

[resrchengee]

ahhh.. great idea! Thanks!