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problem with network variable using two instances of LV

I have a working pxi using a network shared variable. i have a windows PC running a LV exe reading the status of the PXI and test results all working fine.


the problem  came when entered a second PXI into the system with the same code. I knew the pc based program would need to differintiate between the two so i created a second varible in the PXI code and named it number 2.


My windows system only sees the firts PXI not the later added PXI...



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Message 1 of 6

Hello auerdoan,


You stated that your Windows system only sees the first PXI not the later added PXI, can you please clarify this statement? Did you mean you were having an issue with the variables? Or being unable to view the PXI hardware in Windows/Measurement & Automation Explorer?


Best regards,


Ali M

Applications Engineer

National Instruments

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Message 2 of 6

Im having a problem with the variables.

Part of my original problem might be each pxi was in a different project. and i had two projects each its own IP. Using this method i did not know how use two differnt variables from two differnet pxi' s with the same program.


if your still following.


i tried a simpler way


i modified my project to include both ip addresses. 


this way In my window environment my vi calls the variable. i made sure that i right clicked and chose the variables from the correct ip.


what i have is two status indicators and two update buttons.

the status tells me what stage the test is in

the update button is for the user at the end of the test he can update the screen with the results.

currently only my second pxi is updating status and also the update works


this is my windows vi alias file

[My Computer]
My Computer=localhost


do i need to bind to source or use the single writer. im going to try to undo the single writer seems like this would could onluy better it but doesnt seem like its for my application.


 i forgot to mention that the varibles i use  were there listed as dependancies for the windows evirment have a blue question mark  but show what is wrong.  


where i have the variables under the ip address there are no blue question marks

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Message 3 of 6

Ive discovered some interisting things on the PXI code.


Remember  that in my windows code i view  variables used in the pxi's. and the two pxi's share the same code different from my windows code.  These variables in the pxi are also viewable in my project the properties show  that they  are network shared. 


today i noticed when i open the pxi code for pxi 2 its shared varible had a property tag of ip two.( and actually this surprised me i didnt think it would have a referance here)


Ok and when i went to pxi 1 it also pointed to ip2

hmm this why the results and were working for pxi two on my windows app.


The problem if i go to view the pxi code in pxi one i change the variable to go to link to ip 1.

than i double back and look at my pxi code in  pxi 2 that same variable would also change to ip1.


Both pxi's share the same code. But shouldnt this be as simple as in making the viewing software pointing to which ip address for that variable.?

i need to look more at the variable used in the pxi  and make it not specific to a IP but just share it.......


Another Round... 


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Message 4 of 6



Are variables with the same names being hosted on the 2 uniques PXI platforms? Do they display as such in Distributed System Manager (Tools >> Distributed System Manager)? Are you binding variables between the two PXI targets?


What is the overall goal of the application? What architecture has be implemented to mitigate race conditions in the multi-system environment? What behavior are you expecting form the system? What behavior are you seeing? 


Please do not hesitate to post code, diagrams, or screenshots to further illustrate the application. It can be difficult to track asynchronous network communication in a text-based explanation.


Thank You, 

Patrick Corcoran
Application Engineering Specialist | Control
National Instruments

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Message 5 of 6

Are variables with the same names being hosted on the 2 uniques PXI platforms? Yes


Do they display as such in Distributed System Manager (Tools >> Distributed System Manager)?

 im using lv 8.5  i dont see that term in my project or LV


and trAre you binding variables between the two PXI targets?


What is the overall goal of the application? 


I have two pxis with the same code.

Now on a seperate computer running windows i have a program that reads the results and the status from the two.


i have one project with the two pxis and there IP address


Is it possible with my project as stated to have a windows LV program reading the two pxis  im using network variables

im a little confused with the target relative or absolute setting and what i would need to do on my window program to read.

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Message 6 of 6