LAVA 1.0 Content

QUOTE (Yen @ May 30 2008, 08:30 AM)

I believe the terms "context" and "instance" are interchangable in this case. I personally prefer "application instance". An app instance determines all kinds of things.

Here are some examples of things that have to be unique within an instance:

• Queues, notifiers, etc.
  
• VI names (CTLs, standard VIs, global VIs...)
  

To open a reference to an instance, you use the Open App Ref primitive and give it the machine address and port number. The port number is what determines which application instance you connect to. Another key point is that if you want to connect to another instance in the local machine you HAVE to connect something (e.g. "localhost") to the machine name input, or it will open a reference to the current instance. This is most likely the source of your problem.

Once you have the application reference, you can operate on the VIs within that application (at least the ones you have permission for).

As for using the VI name - as I mentioned, the VI has to be already loaded in the application instance you're using. In this case, because you didn't actually connect to the other instance, you got the 1004 error because the VI was not loaded in your instance.

Here is a quick image of what I had in mind.

http://lavag.org/old_files/monthly_05_2008/post-29-1212150784.png' target="_blank">

See the name mangling

Ben

I love Tags !

Cool ! :thumbup:

QUOTE (Yen @ May 30 2008, 01:37 PM)

As far as I can tell, the issue here is with the programmatic setting of the VI server properties. It looks like the settings are only applied after the VIs in project A go idle. I'm not sure, but I think this is a bug.

In any case, if you run the VI from project A, stop it and then run it again, the FGV should work in project B. For me it worked earlier because I set the settings manually (by right clicking the My Computer icon).

Hmmm... this has to be investigated, indeed.

Other point is that I can't find how to open a ref to a VI in a specific project/context.

If someone can clarify the difference between a context and a project, that would help me to understand.

QUOTE (Yen @ May 30 2008, 01:37 PM)

If I only give the VI name I get error 1004 :

LabVIEW:  The VI is not in memory.

To load a VI into memory with the Open VI Reference function, a path must be wired for the VI Path input.

QUOTE (Yen @ May 30 2008, 12:34 PM)

[...](make sure your firewall allows that traffic and that you use a unique port for that project) and pointed the "PC" VI to that port.

I have.. .

Using the the "get ctrl value" method works (*only* if the FGV's front panel is opened) but it make me think that the VIserver settings (port, VI access list, etc.) are correct, so the reference to the FGV is fine.

The "call by ref" method give no error at all, but I think that I am getting a reference to "another instance" of the FGV because if I add a "write" case using the "call by ref" method, project B write to the FGV and reads what it wrote, the same for project A.

How to do to have only one instance of the FGV and each project refering to it?

See attach code

corrections to do before running :

- in B project, in the VI B_reader_loop.vi change the "shared FGV's parent dir path")

- on both project adapt the port number to your setting (mine is 3385)

http://lavag.org/old_files/post-7452-1212145549.zip'>Download File:post-7452-1212145549.zip

EDIT :

Ok Neb,Yen,

I am just seing your posts now, I will try that.

In the end opening a reference to the project (which is a labview "context" if I understand well) sounds the correct way to do. Referring to LabVIEW turns out to open another instance of the pointed VI in the separate LabVIEW "context" that is the second project.

It's cool to learn, thank you guys !

Yen, I set 3385, because my labview 8.5 is set with 3385

* : I am not sure that "context" is the appropriate technical word for what I mean... I am not a proper software engineer (I use to be thermal engineer )

QUOTE (Antoine @ May 30 2008, 06:08 AM)

Hi Yen,

Thanks for the link .

I implemented the "call by reference" like in the example you pointed, but it just doesn't work and returns no error.. is the there any particular settings to set on the shared FGV to make it work ?

Side remark : When the 2 apps are on the same PC it seems to me more difficult than doing it with between a host PC and a RT target. I say this because I did it 2 years ago quite easily with LV 7.1 and I was expecting it to be straightforward..

Is there a significant change on this between LV 7.1 and LV 8 or is it just that I missed a detail of some kind ?

I have not done this LV 8.+ but I thought about it when the proj was introduced.

I believe Opening a ref to the proj that has the VI and then find a ref to the FGV running in that proj. Watch for name mangling if in a library.

And yes use call by reference.

Ben

QUOTE (Yen @ May 30 2008, 11:27 AM)

I'm guessing that the front panel needs to be at least loaded for the set control value method to work. You can test this by adding a property node for one of the controls to the code.

The better solution is to use the call by reference node. You're already opening the reference with the VI refnum type, so this should make it much cleaner and easier. A simple modification and testing of http://forums.ni.com/ni/board/message?board.id=170&view=by_date_ascending&message.id=254951#M254951' target="_blank">this example on two projects seems to work fine when the FP of the FGV is closed.

Hi Yen,

Thanks for the link .

I implemented the "call by reference" like in the example you pointed, but it just doesn't work and returns no error.. is the there any particular settings to set on the shared FGV to make it work ?

Side remark : When the 2 apps are on the same PC it seems to me more difficult than doing it with between a host PC and a RT target. I say this because I did it 2 years ago quite easily with LV 7.1 and I was expecting it to be straightforward..

Is there a significant change on this between LV 7.1 and LV 8 or is it just that I missed a detail of some kind ?

Hi all,

As mentioned in this thread, since LV 8.2 it is not possible to share a queue between 2 LV instance.

I have to LabVIEW projects (A.lvproj and B.lvproj) running on the same machine and I'de like to make them communicate by "sharing" a FGV.

Basically :

- the shared FGV VI is in project A

- at start, the FGV is set to be accessible using VIserver

- on certain event a value is put into the shared FGV

- project B opens an application reference using IP and port number (the same set by project A)

- project B opens a VI reference on the shared FGV to read a control value

I must be missing the point because it only works if the FGV's front panel is opened... see my code below

Can anybody help me on this ?

QUOTE (PaulG. @ May 29 2008, 01:24 PM)

Thanks anyways, guys, :thumbup: but none of these solutions appear to work. Looks like it is LV-specific. I have yet to duplicate a right-click from ANY keyboard combination in the LV environment in any case. I'm using GoToMeeting. I few years ago I used GoToMyPC for similar work and don't remember the right-click not working. Have you ever tried to change a tunnel to a shift register without the right-click?

I've used WebExMeetMeNow to code in LV with no issues.

Wild guess:

Could this be an auto-tool selectin issue?

Done guessing.

Ben

QUOTE (jpdrolet @ May 29 2008, 02:36 AM)

The joy of scripting.

Nice example....

and only with scripting, we can watch what you have done

QUOTE (Yen @ May 28 2008, 02:15 PM)

...

As for different wires crossing each other, that was my initial guess, but it doesn't fly - when wires cross in newer versions they always have a boundary.

Well I have to admit you taught me something I never noticed!

So it looks like an older version of LV is the best guess yet.

Ben

Nah it can't be an older version since there is a project drop-down. Don't worry Yair, you are trapped in LV 7.1 land so we'll let that one slide.

My only guess is that those are over-lapping wires not the same wire looping over itself.

Ben

QUOTE (Michael_Aivaliotis @ May 28 2008, 04:09 AM)

No Photoshop required. Written, Drawn in pure G.

Just put the whole VI diagram on the back of the T-shirt.

Hmmm....

How did you get what looks like loops in the wires?

Ben

QUOTE (TobyD @ May 28 2008, 11:44 AM)

Etch-a-sketch frustrated me as a kid because I could not render a circle. I really think that Trigonometry is a pre-req for etch-a-sketch use. Then all the kid has to master is producing a sine wave with one hand and a cosine with the other.

Ben

QUOTE (Michael_Aivaliotis @ May 28 2008, 04:09 AM)

No Photoshop required. Written, Drawn in pure G.

Just put the whole VI diagram on the back of the T-shirt.

And this message on the front of the T-shirt: Don't click on Clean up wire!

QUOTE (Michael_Aivaliotis @ Dec 2 2006, 05:24 AM)

CRELF

Hey guys and gals. This thread is the beginning of a potentially long thread. Here, whenever the need arises, I will select a LAVA member who I feel has been a significant contributor and or helper.

I think it's fitting to start this thread by spotlighting a member who has helped me quite a bit over the last few months: crelf. Chris has helped a lot in supporting the code repository by reviewing code submissions. He has also posted an astounding number of posts. I think he will surpass me as the number one poster pretty soon. Keep up the good work!!

...

CRELF is first again!

If you check out the most recent NI Instrumentation Newsletter (Q2 2008) you will find that CRELF has written up a nice article on Fuzzy Wires.

Does this make him the first LAVA member to get an artilce published in the Newsletter?

I believe he is the first LabVIEW Champion to do so.

Congratulations Chris!

Nice article.

Ben

Where does he find the time?

QUOTE (JDave @ May 27 2008, 12:43 PM)

I think you misunderstood me a little. I think most religions accept that there are things we do not know, and things we don't or can't comprehend, which are 'mysteries'.

I was referring to when religion does explain something, or there are scriptures that state something, and it is convoluted or contradictory. To state that we can't comprehend it seems to be an easy way to explain away seeming contradictions or confusing language. Perhaps we can't understand the concept completely, but to immediately retreat to a position of "We CAN'T understand it" seems hasty and overly simplistic.

P.S. Science is one of those areas where you are discouraged from breaking the law, but if you actually succeed in doing it you may end up with a Nobel Prize.

I believe it was Goedel (sp?) that showed that a system could not be proved from within itself. Being an element within the system "universe" we should not be suprised to find that we can not prove this system.

I think it was in a book "Five Scientist and Their Gods" that I read that one of them thought the universe was a giant quantum computer that was executing God's program.

Just my 2 cents,

Ben

QUOTE (Justin Goeres @ May 27 2008, 11:20 AM)

So then you can confirm that the Spooky Graveyard and Secret Old Mine are real?

They did not exist (to the best of my knowledge) when I lived there, but I am not going to take it personally that something called "Old" only came into existence after I left. Concidering mines are mostly dirt that would make me "older than dirt".

Ben

Say I wanted to deploy Tomi's example as an exe that would allow other shapes to be added latter (example:customer wants an octogon added)...

from what I understand I would have to re-compile the library that houses the class.

Are there any other things I'd have to adjust to allow for the addtion of other shapes (aside from the menu that allows which shape to drop)?

Ben

"sneaking up on OO one concept at a time"

QUOTE (Phillip Brooks @ May 27 2008, 06:13 AM)

Will your next block diagram http://yvettesbridalformal.com/vettemap1.html' rel='nofollow' target="_blank">look anything like the map to her shop?

And imagine my suprise when I actually understood that map!

As an "Air-Force Brat" (34 years ago) I lived on Tyndall air force base and attended JR high school in Panama City were we had the oppertunity to pass the paper mill (NOT a treat) going both ways.

Ben

QUOTE (Michael_Aivaliotis @ May 22 2008, 07:01 AM)

Here's a challenge for ya. Figure out how to control your home (or anything else for that matter) via Twitter and LabVIEW.

Se here for some inspiration.

Here's another shot, with video.

Control your home using LabVIEW...

http://www.iconag.de/downloads/B-CON_engl.pdf

B-CON is a real LabVIEW for "Home-Automation..."

Recently I had similar problem. My application W/ NI-VISA had conflict with Agilent application w/ VISA. I had to uninstall Agilent application and re-install NI-VISA to make my application works. I didn't try to make both lived together. Then I would also be interested to hear those which succeeded with Agilent VISA and NI-VISA.

Thank you AQ!

Your posts are required reading for me. THe following may sound like a back-handed compliment but please take it with my most sincere thanks.

You are the BEST thing (LV mentor) since sliced bread (Greg McKaskle) !

And (while I am at it) Thank you for all of the work you put into (clarify if wrong)

1) Polymorphic queues (their performance blew me away)

2) Config files (Forced me use OO before I learned how to spell "OO")

3) Resize objects dialog (save sme time and wrist-wear on every project)

4) LVOOP ( the beauty of which is just starting to bloom in my minds eye )

Ben

QUOTE (Michael_Aivaliotis @ May 21 2008, 01:55 PM)

Ok, so NI is always trying to be hip and cool (but of course we all know only LAVA members can claim that)....

Looking closely I have to say that is rather sad.

1) They have not even spelled LabVIEW correctly.

2) I have heard of Certified LabVIEW Architects but what is a Labview Certified Architect (hoping I do not have to take another test)?

Ben

PS: Most of the time I have absolutely no idea how a word should be spelled but LabVIEW (and my last name) are are examples where I care.

QUOTE (martin@aerodynamics @ May 15 2008, 09:25 AM)

even then a plus needs two inputs...

(ok you could make a vi with a custom (plus) icon... however)

Yes I know the dead-line has passed but it worth sharing anyway.

Christian posted this strip in this thread.

Ben

QUOTE (rolfk @ May 21 2008, 01:19 AM)

...

Put it on my age and the fact that my eyes aren't as sharp anymore .

...

Rolf Kalbermatter

Same here!

I prefer the 17" Laptops, and for office work, dual 24" flat-panels work nicely.

http://lavag.org/old_files/monthly_05_2008/post-29-1211385011.png' target="_blank">

Ben

I still have an operational nixie tube meter in my shop. i bring it into the office to show the younguns what life used to be like.

Ben