Programmatic creation of shared variables

[Doug M]

Khalid, thanks for noticing this, I'll get the example updated. The API for programmatic creation of libraries and shared variables has changed a bit from 8.0 in 8.2, but should hopefully be simpler.  If you have LabVIEW DSC 8.2, there is a good example called Library Generation that ships with the module that shows the new API as well as includes some good subVIs for setting all the DSC parameters of shared variables.  There are four VIs that can be used for programmatic library and shared variable creation that ship with LabVIEW regardless of the DSC module, but these VIs did not make it onto the VIs palette. They are located at C:\Program Files\National Instruments\LabVIEW 8.2\vi.lib\Utility\Variable.Attached is a simplified example that shows creation of a shared variable and library regardless of whether DSC is installed.


Programmatic SV Creation.lvproj:
http://forums.ni.com/attachments/ni/170/201084/1/Programmatic SV Creation.lvproj


Programmatic SV Creation.vi:
http://forums.ni.com/attachments/ni/170/201084/2/Programmatic SV Creation.vi

[Adnan Z]

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[dliechti]

Hi Adnan!
Thanks a lot for your detailed answer!
I would be very interested in the DSC Module. I really have to interchange data between a host-PC and a realtime target (PXI). Beside that I have to communicate between an executable and dynamically called VIs (which aren't part of the executable).So the queues, functional globals and so on won't work - I need Shared Variables, Data Socket or TCP/IP communication.
I was thinking about creating a sort of data module. It would be a functional global where I store my data in shared variables instead of shift registers. For example to manage double values I would have two Shared Variables: A 1D string array and a 1D double array. One holds all the variable names and the other holds all the values. With array-operations I could create and delete variables at runtime. The same would work for other data types and even for arrays. To manage 1D Arrays I just need a 2D array and so on.
I once implemented something similar but there with normal functional globals and not with Shared Variables.
 
Actually the only thing I would like to do is to add a library of Shared Variables to the running executable. When programming the dynamic VIs which communicate with the PXI-System I have to define the Shared Variables anyway. So they exist somewhere. It's just when I want to run the VI dynamically I get an error which says that the VI isn't executable (because the Shared Variables are not known...).
 
Cheers, Dave

[MScap]

hi i need some help with regard to creating shared libraries and variables programatically.i am making use of the vis 'create or add library to project' and 'create or add variable' vis to create libraries and variables programatically.i create around 10 libraries and around 5-6 variables under each library in a single run of the vi.the vi runs fine when all the library names and variable names are different.as is obvious, i get an error 1051 when i enter an existing library/variable name, in my second run.my libraries and variables will not be deployed as i write/run the code. so, if i try to use 'get process list' and 'get variable list' vis, i cannot get the details of the library names and variable names created in the previous iteration of the FOR loop.i hope you got my point.is there a method to find if the library name/variable name is already used?i wish to use this vi scalably. i mean, if i might required to create 100 libraries, i just need to change the FOR loop iteration count.ALSO, if i try to use 'get process list' or 'get variable list' vis, i will get lirbaries and variables present in other projects as well.using this list as a chekc will not allow me to create a library/variable in an other project with exisitng names.is there a solution to this?how do i find out if there is already a library/variable in the given project with the same name - as i run it?

[MScap]

hi compeltely unrelated to my earlier post in this thread, i have another question.i used property nodes to set the scaling properties of a shared variable.when i configured the values in the order:Scaling Enabled, Scaling Type, RUMax, RUMin,EUMax,EUMin i got the error '(-1950678978) at the output of the "Library" invoke node: "LabVIEW: (Hex 0x8BBB003E) A shared variable may only be added to a project library."'when i changed the order to:Scaling type, RUMax, RUMin,EUMax,EUMin,Scaling Enabledit ran perfectly.Qus: Why did that happen?Property nodes follow top-down procedure. How can i configure sclaing paramters before enabling Scaling?Should it not Enable scaling first and then configure the parameters?Thanks

[Eli_S]

MScap, You can get a list of the variables and libraries in a specific project using VI server and you can then use these names to check if a specific name already exists. Furthermore, using the VI server method, you do not need to deploy the libaries for them to be found. Please take a look at the attached example. I posted it in LabVIEW 8.5.1 if you need another version please let me know.As far as your second post, can you please show a screenshot of how you are setting the property nodes?


GetVariableList.vi:
http://forums.ni.com/attachments/ni/170/330087/1/GetVariableList.vi

[MScap]

hello! Thank you for the reply.I shall try the vi and update you.coming to my second post, i got to know that there is a specific order of configuring the Shared variable using a property node.I followed the order and solved my issue.thank you! :smileyhappy:

[MScap]

oh wow!!! that was working very very fine!!I wanted something just like that!thank you so much!!:smileyhappy:

[blackperl]

Hi all,I have an application where i am using a set of cFP controllers and a pair of Servers. I am using Shared Variables for transferring data between cFP and Server by binding the cFP variable to Server Variable.I am using these servers for redundancy purpose. I made some logic to intimate cFP whichever is active.But is it possible to programmatically bind the cFP variables to the Active Server. i need to change the binding address whenever a server switching is happened.Waiting for a reply.Thanks and Regards,Blackperl