Which Boolean is giving error when loading Labview Real-time

[Shreesha]

HI,
I had previosly writen a comunication program with Labview 7.0, which worked properly. Now I am updating to Realtime 7.0. When I try loading the VI, I get error saying latched/snap boolean cannot be used. I have corrected for these booleans, but the error still pops up when I try loading the VI into my PXI Realtime controller.
Is there any way to find out which boolean is causing the trouble? My program is huge and I think I have changed the mechanical switching action of all of the boolean switches. Why does not the Real-time show the cause of the error, when the normal labview debugger shows what is causing the error.
Reply asap.
Thanks.

[jdigiova]

Hello,

You are correct that the error does not cause a broken run arrow and take you to the cause. I have taken this as a product suggestion and passed it on to the developers. Currently there is no easy way to determine the mechanical action of the switches aside from right-clicking on them. You need to make sure none of your switches are set to "switch until released" or "latch until released". The error that appears does not explain that clearly so you may still have some switches with invalid actions.

Also if you build the VI into an executable it will function. I will pass this inconsistancy on to the developers as well.

Regards,
Joe D.
National Instruments

[Shreesha]

Hi,
Does it mean that my original program with the original action of the boolean switches (contains switch untill released), if converted into an exe file and then loaded into the PXI RT system would work??
Please let me know asap.
Thanks.

[CoastalMaineBird]

Usually the boolean controls with special mechanical actions are only for VIs that are on-screen (the highest-level ones). That's where I would look first.

However, it's possible a control got copied to a lower-level VI where the Mech. Action was not needed, but not harmful, either.

Just a thought - you could try downloading your low-level VIs one at a time into the RT board, and seeing which one(s) complain.

[jdigiova]

Yes that is correct when you build your VI into an executable the mechanical action of "switch until released" is supported.

[Shreesha]

Hi Joe,
My program has user interface, and needs the user to control the working of the VI. Now, how can I create an exe file of this VI, and then embed it into PXI RT system, and still the user being able to see the frontpanel and work on the VI's from the normal computer.
I am pretty new to labview. Please let me know the step by step procedure.
Thanking you.

[jdigiova]

The best reference for you on how to build an application would be the RT Module User guide. Below is a link to the manual. Chapter 7 deals with deploying the application.
http://digital.ni.com/manuals.nsf/websearch/264850C05114C9DB86256D2C00674D50?OpenDocument&node=132100_US

You have many options when it comes to controlling an application running on a remote system. It seems you may not need the application to start automatically on boot-up therefore you can follow the instructions below:
1)Make sure LabVIEW is targetted for Windows
2)Launch Application Builder from the Tools menu
3)Select the directory and name for the executable to be saved (for example c:\my_app.exe)
4)Add your VI as a top-level VI and any suppor
t files you may need
5)Build the executable
6)Create a shortcut to this executable by right-clicking on its icon and selecting "create shortcut"
7)Right-click on the newly created shortcut and go to the "properties" page.
8)In the Target field you should see the location of the executable you built (for example "c:\my_app.exe").
9)Add -target ip_address to the end of this field. It should look something like:

"c:\my_app.exe" -target 127.0.34.78

Now whenever you click on the shortcut it should launch, download, and run on your remote machine.

[Shreesha]

Hi Joe,
I shall try the steps as given by you, and shall let you know of the proceedings. Also, when I load the program by targetting the RT system, it gives a warning saying Frontpanel events not supported.
Now, if i create an exe file like you said, will this be taken care off?? Are frontpanel events supported in RT, if loaded as an exe?
Please let me know.
Thanking you.

[Shreesha]

HI Joe,
I built the application and targetted the RT system. That part worked. But, I still get the error saying "VI's using Latched/Snap Boolean cannot be used".
So, I wrote a small VI with just one switch with mechanical action as 'Switch untill released'. I built an application with it, and targetted the RT system, like you described. I get the error as 'VI's using Latched snap Boolean cannot be used'.
Please let me know what I am doing wrong. I have an PXI-8186 RT system.
Also, can I have your telephone number, so that we can correspond more easily.
Thanks.

[CoastalMaineBird]

I get the error as 'VI's using Latched snap Boolean cannot be used'.

The mechanical actions are useful ONLY for VIs having a front panel - since you are loading them into an RT system, that is not the case.
I think you should treat that as the problem, as I suggested previously.