reference of property node

[phyyu]

Hello guys,

In using the property node, I confused with the reference terminal there. Should I create some special reference for the control ( a button, for example),but obviouly I could not connect the button directly to the reference terminal. I find out an example about this which attached in attachment. How could I creat a stuff like that? So appreciate!

[P@Anand]

If you are using the property node in the same vi where the control (button) is available you can create an implicit property node (Right click the control and go to the property and select one) else if you want to use the reference property node you can create a reference for the control and use it else create an indicator out of the reference and change it to a control (which looks similar to the one you showed) also you have lot other way to do it.

good luck

[phyyu]

Thank you for your reply.  I known about the implicit property node, I actually confused about the dynamically linked property nodes. Should I create a VI server reference and link it to the reference terminal of this dynamically linked property node? If so, another problem poped out, I would like to use this property node in a subVI, which should have a general control reference (this subVI should be used for difference button controls), the subVI itself should not have any specific control. What should I do with this property node in the subVI? Thanks a  LOT!

[phyyu]

I found out a Ctrl Refnum in the block diagram menu, should I use it to link with the property node in subVI?

[apok]

this might help....

the stop button is used as a control(read from top level), while the rest are indicators(write to top level)

[phyyu]

Thanks. May I consider in this way... The VI server reference on the block diagram could be use when you have certain controls or indicators to reference. The ctrl refnum on the front panel could be used as a general reference when you do not have certain controls or indicators to link, or say an open object? In addition, any difference between reference and refnum?

[Alex+ra · Accepted solution]

Phyyu,

VI server references follow the object-oriented class structure. A VI Server reference can refer to a wide range of objects, like a control, indicator, VI, variable, etc. VI Server references can be as strictly or not strictly typed as you would like. A control/indicator reference specifically references a control that you pass to it. You can require the reference to be more strict by right-clicking the reference and using the menus to select which class you would like to reference. One possible class tree may look like this: VI Server>Generic>G Object>Control>Array. Now this reference requires a pointer to an array control, and will not accept any other type of control. If you use this reference control to create a property node, the properties will be specific to the array class.

A refnum is simply a numeric value that refers to a place in memory. Reference and refnum are used somewhat interchangeably in LabVIEW. 

Hope this answers your questions! Check out the LabVIEW Help files for VI Server references to learn more about them.

Regards,

Alexandra Valiton

Applications Engineer

National Instruments

[phyyu]

Thank you so much for your reply. It is really useful. I am so appreicate if you could kindly show me the answer to two additional questions I found in an example.

The attachment CtrlRef is a notifier in the event structure, I could not find out how to get this.

The attachment button reference, there is a red star in it, I right-clicked the reference, found out the "include data type" has been checked, what is it mean?

Thanks for your concern.

Sincerely,

Yue

[Alex+ra]

Hi Yue,

The CtrlRef notifier is determined by the type of event case selected. There are different notifiers for Mouse Click, Value Change, and Timeout. You can resize the notifier box to see more options, because some event cases have many different notifiers.

The red star indicates a strict reference. "Include Data Type" means that this reference is not just any control, but a Boolean control. You cannot pass a reference to a Numeric control to this input of the VI. 

I hope this answers your questions!

Regards,

Alexandra

[phyyu]

Thanks a lot!