顶层界面如何与子VI的数据实现同步显示。

[StevenGerrard8]

我有一个子VI在while中连续采集并绘制出图形，但在顶层vi中需要同步显示出子VI中绘制的波形，该如何实现？谢谢！

[ThomasYoung]

子VI设置端子，连接到顶层的图形输入端不可以么？

[StevenGerrard8]

是这样的，子VI（SOUND DAQ.vi）中采集是在一个while循环中连续采集的，采用接线端的话，是采集的条件结束返回时，主VI才能显示出波形，但是我需要主VI中能实时显示出当前子VI中的波形以实现实时监控信号状况。

我现在使用全局变量和外部并行While循环不断的去更新波形（如图中声音频谱图），但这样感觉不太好，想问问看大家有没有更好的办法？

另有问题补充：在两个或多个并行WHILE循环中，如何使用一个while循环当中的按钮去结束这两个while循环？

 

Message Edited by StevenGerrard8 on 12-14-2009 05:16 AM

[ian_fung]

Create a Reference of the indicator (in caller VI), wire it to the sub VI (Sound DAQ.vi must have Reference input created too).

Now, in the sub VI, you may create Right-click the Reference and create property i.e. Value, and have this property updated with the Sound DAQ's data...

Try it out and see 😉

(Hope I did't remember that steps wrongly :p) 

[ian_fung]

Hi,

Attached is quickly done up example that uses Refnum (Reference) for updating caller's control/ indicator with sub-VI's data at runtime.

Attention!

Please beware of how sub-VI is terminated... In this example, sub-VI stops after 10 iterations. 

[StevenGerrard8]

A little busy this day, i appreciate your help very much, and i had notice your sample works excellent, but there are error in my program when i follow your instruction. Can you please tell me why?

Message Edited by StevenGerrard8 on 12-17-2009 10:08 AM

[ian_fung · Accepted solution]

Did you pass the Reference in from the caller VI?

You must call the sub-VI i.e. SoundDAQ.vi once from the main-VI (caller), before you can run and debug the sub-VI alone.

If you open the sub-VI immediately after launching LabVIEW,  you will get such error as the control/ indicator Reference is not passed in to the sub-VI, yet. 

Message Edited by ian fung on 12-18-2009 09:09 AM

[StevenGerrard8]

Not try yet because i had finished the program in the gloable variant method. maybe later^_^

But thank you anyway!