Creating Express VI's -- A Starting Tutorial

[m3nth]

Background information for this post:

I wanted to learn how to make an Express VI and was able to do so thanks to PJM labview ( :arrow: Creating Express VI's) and Jim Kring ( :arrow: Recursive LabVIEW Calls, Using scripting/OpenG/VIServer to create recursion). Many thanks to them for their information and source code which I have compiled and used here. :thumbup:

In order to help me understand how Express VI's work I made a Word document that essentially turned into a tutorial on the way NI has set up Express VI's, to the best of my understanding. Not only are they fairly simple once you take the time to try and understand them, but you can make your own with a little bit of effort and a starting set of template files.

Attached is the Word document Download File:post-360-1095356483.doc, the set of template files Download File:post-360-1095354541.zip, and my own Msg+ Express VI Download File:post-360-1095354635.zip which I was in dire need of as it greatly expands upon the flexibility of the Display Message to User dialog box that is included with LabVIEW. In order to be able to use the Express VI that I've included however you will need to run the Tagger.vi to link it correctly since it is linked using an absolute path (which I haven't found a workaround for). It works fine on my system but won't be able to find "Msg+ Express Config.vi" until it is tagged with the absolute path on the machine you're using.

My understanding of the Express VI's is probably limited so I'd be interested in anyone else filling in any other information I may have missed, or any other comments/questions on getting the code to work. Everything works right for me so post problems if you have any.

[Michael Aivaliotis]

That's great! I'll move it over to the LabVIEW FAQ in a few days...

[geeth]

Thanks for the very useful tutorial. Have you tried using some of the support vi's such as the "ex_Wire Con Pane.vi"? I was examining the Configuration VI of the Simulate Signal Express VI that ships with LabVIEW. There is a vi included called "ex_Wire Con Pane.vi" which seems to determine the terminals that will be displayed on the connector pane of the Express vi when dropped on the block diagram. I am unable to find any documentation to wire the inputs correctly to this vi. Specifically, there is a terminal called "all Controls" which is a string control array of control names - the order in which the control names need to be specified seems to be important, but I cant figure out how to determine that order.

I would like to know if you have ever had to use this vi and figured out how the inputs need to be wired.

[m3nth]

Thanks for the very useful tutorial. Have you tried using some of the support vi's such as the "ex_Wire Con Pane.vi"? I was examining the Configuration VI of the Simulate Signal Express VI that ships with LabVIEW. There is a vi included called "ex_Wire Con Pane.vi" which seems to determine the terminals that will be displayed on the connector pane of the Express vi when dropped on the block diagram. I am unable to find any documentation to wire the inputs correctly to this vi. Specifically, there is a terminal called "all Controls" which is a string control array of control names - the order in which the control names need to be specified seems to be important, but I cant figure out how to determine that order.

I would like to know if you have ever had to use this vi and figured out how the inputs need to be wired.

2659[/snapback]

After getting what I needed working, I didn't look into the mystery of express VI's. After examining differently configured instances of NI-Scope Express, I realized that the express VI's that NI makes are probably heavily scripted and rely on VI's such as the one you discovered. I have no idea on it's functionality however--good luck.

[Mike Ashe]

Excellent tutorial and example. Perhaps a bit of an Open Source toolkit can be slowly built up around this as time goes by. Not sure what NI's reaction to this might be though. Keep up the good work!

Hmm, along these lines, it might be useful to have a list of express VIs that people really need or a place in the LAVA site (and/or OpenG) that will start a library of express VIs and VI requests....

[didierj]

Not sure what NI's reaction to this might be though.  Keep up the good work!

2682[/snapback]

The answer from NI can be found in this post:

NI censoring the devzone..., FYI

[JackHamilton]

I think NI forum hosts should consult their attorneys before making such statements.

I don't understand the application of the word 'illegal' in the censor statement. Unless Express VI's are patented and they are referring to patent infrigement. If that's the case - you can't use the world 'illegal' because it's not illegal to disclose a patented technique - all anyone would have to do is look up the patent - To get a patent you have to dislose the details of your technology/technique which is then published in the public record.

Perhaps they are confused with proprietary and patented...

If the information is proprietary - then publishing such information would be 'illegal' only if the party disclosing the information had entered in and violated a disclosure agreement with NI. As the forum itself is hosted by NI - it can't violate it's own proprietary agreements.

I don't think either is the case. I think there is a kinder/gentler wording NI can use to say that certain information is outside of the Developer topic and leave it a that.