25 replies to this topic

[lordexod]

Does anyone have specific documents about "XNode" and "ExternalNode" for LabVIEW FPGA? (hdlnode.jpg, createxnode.jpg)

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[Aristos Queue]

Yes. I do.
No, I won't share.

[lordexod]

Why do not you want to share?

[Wouter]

Proberbly because its classified

[asbo]

You're such a tease, AQ.

[Aristos Queue]

Hey... at least you guys have gotten me to the point of admitting that XNodes even exist. Time was I would have accused you of hallucinations and swamp gas reflecting the light of Venus for believing in XNodes.

lordexod: The XNode tech is reserved to National Instruments for a long list of reasons, not the least of which is that it requires some significant contortions to avoid the traps and pitfalls of working with them. XNodes invoke G code to do their work. There are various operations that are not stable to do while LV is doing certain operations (loading a VI is not always safe, for example, depending on what else LV is doing at the time). As a matter of fact, XNodes have been mostly abandoned by NI for further development ourselves because of their issues. They work great for some things, but poorly (or crashily) for others, and it is very hard to tell in advance whether a given use case will turn out to be the former or the latter. We'd like to have a more complete "G written in G" solution, one that we could release to customers, but XNodes aren't it.

[Jon Kokott]

Check this out,

https://decibel.ni.c.../docs/DOC-13859

Then check out some more of darin's black magic. There is an Xnode tool in the code repo as well that will help you as well.

[Darin]

I usually buy the "it is too complicated for the masses" argument until I try using XControls. Compared to those XNodes are a walk in the park.

[daal]

Does anyone have specific documents about "XNode" and "ExternalNode" for LabVIEW FPGA? (hdlnode.jpg, createxnode.jpg)

Look at this

How did you enable the creation of a Xnode and selection of abilities in your Project ?

[Aristos Queue]

I usually buy the "it is too complicated for the masses" argument until I try using XControls. Compared to those XNodes are a walk in the park.

Ah, but XControls don't have the potential to corrupt your VI if you do them wrong. There's a big difference between "complex" -- which is a reason to put a good UI on something but not a reason to never release it -- and "flakey around the edges" -- which is a reason to keep it in house.

[gb119]

Ah, but XControls don't have the potential to corrupt your VI if you do them wrong. There's a big difference between "complex" -- which is a reason to put a good UI on something but not a reason to never release it -- and "flakey around the edges" -- which is a reason to keep it in house.

XControls can lock you out of classes in rather unfriendly ways (and yes this is documented I know but I still think it's not great that the IDE lets one create uneditable items without a bit more effort to stop you...). Still XNodes are fun to play with and a pain in the backside to work with. It's a shame that that is apparently an unsurmountable hurdle, but hey third (or more ? - External Nodes, XNodes, ...) time lucky

[lordexod]

Aristos Queue: "The XNode tech is reserved to National Instruments for a long list of reasons...." - Not anymore, but for one reason only. I enabled XNode on LabVIEW, as you can see the screenshots.
"Yes. I do. No, I won't share. " - If you do not want to share or exchange,you will not admit publicly that you have something.

Darin: With this "MathNode" a good job. A little bit I know already what is going on with this XNode.

[todd]

lordexod, when AQ says he won't share the information, that in itself is useful information. Since the implied intent was not clear (that XNodes can corrupt a VI), he was then more explicit.

[Darin]

One of these days (I have said this before) I will dust off my XNode Wizard. It automates a basic set of common tasks and makes it easy to create a certain class of XNodes: Growable nodes, dropping template code and mapping the terminals from the template to the XNode, and drawing the image. My own experience is that with the limited set of features I have managed to reverse engineer, they are stable, yet you can still write a broad spectrum of useful nodes, especially since a vast majority of the time you want a subVI with something resembling the type adaptation of primitives without writing hundreds of polymorphic instances. The fact that XNodes ship with LV (ie. Match Regular expression) means that stable objects can be created. Express VIs are using very similar if not the exact same framework.

I can corrupt a VI with scripting, with Write to File, or even setting the current values to default. And just because I can wreak havoc with my reciprocating saw does not change the fact it is my favorite tool in my garage. With great power comes great responsibility.

I do wish that someday I could package XNodes in Packed Project Libraries, they are made for each other. A single package containing one useful top-level object and a bunch of specialized subVIs that are best kept private.

In the meantime, besides the existing resources on LAVA I would check out the following:

http://forums.ni.com...ode/m-p/1293680
(a cool, simple XNode example. Shows handling clicks, type adaptation, and updating the image)

https://decibel.ni.c.../docs/DOC-15362
(a bit of a play, shows a few more abilities and techniques)

Attachment: This is a picture constant which allows drag and drop of common image types (JPEG, PNG). You can place this constant on the BD and then drag and drop an image file to get a constant picture. When you are finished, you can right-click and replace the XNode with a simple picture constant (this avoids the need to distribute the XNode with your VI). I like it as a quick way to get a picture constant without the usual method of read file, draw to picture indicator, create constant, copy, paste. Simply extract the folder and drag the .xnode file to your BD. XNodes can be added to your palettes, just remember to choose the 'All Files' filter when browsing for the .xnode file.

enjoy!

Attached Files

•  PictureConstant.zip   236.07K   48 downloads

[lordexod]

todd: "XNodes can corrupt a VI..." - In LabVIEW is a vi file recovery option. And as LabVIEW or computer the crashes, you can always reset.

Darin: This XNode's is a very interesting.

[lordexod]

Aristos Queue: If you want something for knowledge of the "xnode, externalnode",it write on priv.
Anyone know what is "LabVIEW_LabVIEWInternalTag_PKG"?

[Djed]

AQ's not trying to be mean in denying you internal information on xnodes. First, such documentation was written for internal purposes and as such contains "classified" information. Second, xnodes were not designed as a feature for customers but as an internal tool. As such, believe me!, they are buggy, under documented, flaky, dangerous and unfinished. They are nowhere near a feature we can support and we are not allowed to talk about them. This is not really a "protecting you from yourself" but rather not publishing an unfinished, buggy feature. Maybe someday we'll have the resources to finish and productize the feature. But for now, we are supposed to answer "No comment" according to the lawyers. =)

[lordexod]

Djed:
Second, xnodes were not designed as a feature for customers but as an internal tool. - I am not a customer.
As such, believe me!, they are buggy, under documented, flaky, dangerous and unfinished. - I did not bother me.
They are nowhere near a feature we can support and we are not allowed to talk about them. - This is the forum, you do not have to speak.
You know what it is "LabVIEW_LabVIEWInternalTag_PKG"?

[lordexod]

How bad works XNode's Interface in LabVIEW, you can write such an interface to the WebUIBuilder software.
From what I saw, there are several types of XNode (CXNode, GXNode, HybridXNode).

[lordexod]

I found out what I wanted.