VI High 3 - How to Use Property Nodes in SubVIs through Use of LabVIEW Control References & Refnums

[@thelemur]

That Control - Explicit - Parental advisory joke, that got me going for like half an hour. I dont think i know anyone who can realy appreciate that.

[@Sixclear]

+Anders Pedersen We're happy when you're happy. Thanks for dropping us a line :)

[@Sixclear]

Great question on the error tunnels! The short answer for this case is no. There are several reasons for putting shift registers on tunnels, but the most typical is in the instance where code in the loop is checking the error cluster for an error and then implementing some logic as a result, like stopping a loop, or transitioning to another state in a state machine. In the VI in this video we aren't implementing any logic as a result of the error condition, so the shift registers aren't needed.

[@jonathananderson371]

You have the best LabView videos on KZbin. But this practice exam question confused me in light of this video. Can you clarify? 4. You have a control on the front panel of a VI and you need to modify one of its properties at run time. Which of the following is the best approach you would take? a. Create an implicit property node and select the property to modify b. Create a control reference, pass the reference to a property node and select the property to modify c. Create a linked shared variable and select the property to modify the property d. Create a local variable and select the property to modify 4. Correct Answer: A Topic: VI Server Justification: Property Nodes are designed for modifying front panel objects programmatically. Answers C and D do not make sense because modifying front panel objects is not what variables do. Because we are not using subVIs, answer A is a better choice than answer B because an implicit Property Node will work and does not require the extra inputs that the explicit Property Node requires. References: Controlling Front Panel Objects Programmatically from a SubVI, VI Server Reference

[@Sixclear]

@tsitsibe, no problem. Glad you're enjoying the episodes. Keep posted!

[@liwei9136]

when create the subvi, the control refnums must correspond exactly to the calling vi? or just the type need to be matched? intuitive video, thanks a lot!

[@Sixclear]

Li Wei The data types and the VI Server class must be compatible. In other words, the reference being wired in must the same class or a sub class of the refnum in the subVI. Hope this helps!

[@ivanperezs]

Still very relevant and useful. Thank you

[@ericgoto2459]

What does the error cluster do?

[@porsgaard1985]

Shouldn't the error tunnels have been replaced by shift registers

[@arkaedra]

Just what I was looking for, Thanks

[@matiknik]

Perfect explanation. Tnx for sharing. Cheers! mate :D

[@tsitsibe]

nice!thanks!