Programmatically bind shared variable

Hi,
I'm trying to bind a control to a shared variable, if I clic on properties=>Data Binding, everything is set up correctly, but I get a red flag. Then if I add a white space after the variable path then clic OK. everything is fine and working properly.
My problem is I have to bind hundreds of shared variables so I don't want to modify every single control properties...
Anyone has any clue on what's happening?
Rodéric L
Certified LabVIEW Architect
Attachments:
properties.JPG ‏34 KB
method.JPG ‏18 KB

Looking at some similar code that I had developed to set FP bindings, I included single quotes in the url, for example:
\\My Computer\IO\'PU.Heater_Power'
Maybe the space is satisfying the need for a delimiter of some sort?

Similar Messages

Data Logging a programmatically created shared variable of cluster or array datatype into citadel DB

Hi,
Is there a way to log a programmatically created shared variable of cluster or array datatype into citadel DB?
I have attempted to programmatically create a shared variable of type 'double' and was able to successfully log the same into Citadel DB. In the attachment, Please refer to the attached project SV_TC.lvproj and specifically to SV_W.vi for the code that i have used (W.png file shows the dB in MAX and shared variable in NI Distributed System Manager)
However when i tried the same approach to create a shared variable 'array of double', i noticed that traces are not getting created and hence data logging isn't happening into the Citadel DB. I was however able to write and read the shared variable array without issues. The same is true with cluster datatype also. Please refer to SN_NW.vi for the code that i have used - only difference from SV_W.vi is that i have tried to create a shared variable of type 'array of double'
One observation is that if i create an 'array of double' or cluster in a shared variable library using the project explorer and deploy, i could see that these being logged into Citadel DB.
Hence i want to understand what could be done to achieve the same programmatically? Could you please advice?
Regards,
Sridhar
Attachments:
SV_TC.zip ‏3925 KB

Why is the transaction happening over remote?
Because we need the information to be on our database immediately when they submit it.
I don't know anything about streams or replication.....
The web database is run by the company that hosts our web site. We use PL/SQL to show the pages and output the html. It fetches the data the customer is requesting from our database, but I'm struggling to get the best way to insert into our database from there.

Binding shared variable in executable across network

I can't seem to get a shared variable to bind from an executable on another computer back to a source variable on the main machine.
I can get the remote variable to change with programmatic access. Is it possible to have shared variables in an executable bind to a PSP URL on another computer? This is labview 2011.
I can see everything with NI Distributed System Manager, and the programmatic access changes the remote variable, so it's not a network issue.
Thanks for any insights. This just doesn't seem to work the way NI's online white papers say it shoud.

What I don't understand is why after binding to a specific URL, the "Shared Variable Deployment" screen of the application builder makes the target "my computer".
I probably could get this to work if I changed the network address of "my computer" in the ini file created in Application Builder?
This seem a strange way for this binding process to work. If the absolute target (for shared variable bound to another variable and referencing "absolute") was retained when the VI goes through the application builder, it would make for sense.
I can't get this to work any way with using bound variables. The only way this works is using programmatic access to shared variables in the built app, and I don't consider this the same thing.
My conclusion is that shared variable binding and appropriate absolute references to deployed variable libraries do not survive passing through the application builder with their absolute references intact.

Binding Shared Variable to Source

Dear all,
I'm currently working on a project that requires the use of shared variables. The shared variables will be network published and programmatically created using properties nodes. However I encounter one error and one problem in the process of doing so.
1) I programmatically bind the shared variable directly to the fieldpoint channel (data item) by writing the URL \\10.0.0.1\FP\1AIO\00 when i create the shared variable. The shared variable can be created successfully but when i deploy it, it generates an error which seems to tell me "it is out of range". Can anyone help me to rectify this problem?
2) The 2nd question will be, as my fieldpoint is connected to a DHCP server. At the start when i create the shared variable programmatically, i could bind the shared variable directly to the data item by writing the URL to its property. However, during the process of deployment, the dynamic IP address assigned to my fieldpoint may change . How can I ensure that the shared variable continue to bind to the right fieldpoint channels respectively? even though the IP address changes?
- Or is there any method that I could view all the network data items in a table? a list? or an array? so that I can link them to the URL.
I tried using the data socket URL.vi, I can only select the data item one by one.. this will be tedious for 100 or 200 I/O points..
Will greatly appreciate for any advice and help. Thanks in advance.

Try this.
Give your fieldpoint controller a computer name through MAX. Then instead of referencing it by 10.0.0.1 in the URL's of the shared variables reference it by computer name. So \\MyFPmachine\FP\1AIO\00 instead of \\10.0.0.1\FP\1AIO\00.
Dynamic IP's can definitely cause headaches, and it would be best to use static IP's if possible, but doing this method should help. It seemed to work for me. I found when you browse for the channel in LV, it wants to give it the IP address by default, but it was possible to edit the string and paste in the computer name.
Message Edited by Ravens Fan on 01-10-2007 11:01 AM

Error programmatically deploying shared variable lvlib from an installed app

I'm using shared variables in my app. According to what I've read, I need to deploy the lib programmatically using the app invoke node deploy library. I do this and it works fine for the app exe on my machine. But then I created an installer and tried it on a "virgin" machine and I get a "error 1 at invoke node" saying "an input parameter is invalid." I added an indicator that shows the lib file path I'm using and it's fine. I had left the target IP addr unwired but I also tried 127.0.0.1 just in case. Any ideas what's going wrong here?

Hi:
If including the SVE installer didn't resolve the issue then it looks like there are some other possibilities that are discussed in the following forum threads. Not sure if you've seen these yet, but hopefully they will help.
http://forums.ni.com/ni/board/message?board.id=170&message.id=240865
http://forums.ni.com/ni/board/message?board.id=170&message.id=230033
http://forums.ni.com/ni/board/message?board.id=170&message.id=249345
Message Edited by A Person on 03-23-2009 02:40 PM
Message Edited by A Person on 03-23-2009 02:40 PM
Alex Person
NI-RIO Product Support Engineer
National Instruments

Bind shared variable to multi-channel item

How do i bind a shared variable (array) to a Fieldpoint multi-channel item?
When i configure the shared variable, and click browse to select the network item to bind to, i can select individual channels but there's no "All" tag.

Actually I suspect that the problem is in the National Instruments OPC Server.
DataSocket can read array data types from an OPC Server, but National Instruments' OPC Servers do not publish data in an array format.
Probably the easiest solution is to publish your shared variable in your network but don’t bind it trough the opc server, instead you have to use it like a standard global variable (bind to source method).
Give a look to this document may lead you to a better solution.
http://digital.ni.com/public.nsf/websearch/FA610367EC62574186257118005089F2?OpenDocument
Hope these two tips can help you
FiloP
It doesn't matter how beautiful your theory is, it doesn't matter how smart you are. If it doesn't agree with experiment, it's wrong.
Richard P. Feynman

Do I have to Bind Shared Variables in Executables?

I want to have shared variables work between two executables that will be installed on seperate machines. I've managed to get the code working, but am not satisfied with the approach.
Attached is a .zip file with my project files that contain what I've been able to get to work.
What I don't like, is how I need to have double the amount of network variables. Right now I have a program that is a publisher and another is a subscriber (based on an example provided on this forum at some point). The Publisher has its own shared variables inside a library, and the subscriber has its own shared variables inside a different library. The Subscriber's shared variables are "bound" to the Publisher's shared variables in the project file and is a concrete physical network path that cannot be changed.
Once the executable is made and installed, this works. I've tried getting it to work w/o one of the executables using a shared variable library that contain bound shared variables through a concrete physical network path but I obviously do not know what I am doing. Ultimatly, I would like to have a single shared variable library that both the publisher and subscriber use. I want the publisher executable to post the variables to the variable manager running on the publishers machine, and then have the subscriber program running on the subscriber's machine to consume the shared variables from the variable manager on the publisher's machine.
Please help me!
-Nic

Hey Nic,
I am going to try and answer those questions for you.
If you use the DataSocket API to connect to a variable that resides on another machine, is your local machine's variable engine involved at all?
No, it should not be involved at all.
If the Variable Engine is not used locally, does it need to be included with your application installer?
Yes, it is going to need to included with the installer.
If I'm correct, whats better? To use the variable engine locally, or to connect directly to a remote variable engine?
Can you please give a little more information here? I'm not quite sure if I understand your question.
The default time-out on the DataSocket Read vi is 10 seconds. If you are doing multiple DataSocket reads in the same polling loop, one variable may update but the other datasocket read is waiting for its timeout before allowing the loop to itterate. This creates a really laggy scenario (see progmatic subscriber.vi in the attached .zip). Setting the timeout to something low, say 10msecs, reduce the "lag" but...
Having the ability to set a decent time-out is a really nice performance feature that isn't availabe to you when you Bind to a shared variable (I don't think). It may make performance since to not do any loop iterations until the data from the host has changed.... how to manage this w/o seperating each read into its own loop however is my question.... ???
Can you please explain this a little more as well? If I understand you correctly, it sounds like you have many datasockets open in one while loop. Are you using one datasocket per variable?
Is there any unseen advantages with using the National Instrument's Shared Variable API over the DataSockets API?
Shared variables are in general more easier to use, and provide a simple way to implement the idea of passing data between machines. Obviously, using TCP, you can create more control using your own protocol to exchange information, but in general, Shared Variables are normally just easier to use.
Feel free to post any questions or dicussion issues here.
Regards,
Kevin H
National Instruments
WSN/Wireless DAQ Product Support Engineer

Problems with communication across a network using shared variables

I have two programs(projects) running on two different computers connected with a LAN. I am using LabVIEW 8.0, and the DSC-module. The program on one of the computers have measurements that I want to collect and show on the program running on the other computer on the network. I choose the indicator where I want to show the data, select ''Properties'', ''Data binding'', ''Shared Variable Engine (NI-PSP)'', ''Network Items'' and then browse for a Network...but the problem is that in my ''Network Neighborhood'' There is only one computer...and that is the one I am one...not the computer on my Network that I want to communicate with....
Have anyone any suggestions on how to solve this?
Kind regards Mari

Mari,
Check this link regarding trouble shooting network-published shared variables:
http://digital.ni.com/public.nsf/websearch/6E37AC5435E44F9F862570D2005FEF25?OpenDocument
This might be a firewall issue, so I would check that first.
Frode

CFP-1808 shared variables timestamp

Hi,
I need to control and acquire data from a cFP Ethernet module (cFP-1808) to a PXI RT system. I have tested two ways of doing it:
1. Bind shared variables to the Fieldpoint channels. Works great except for the fact that I have to record the timestamp of every single channel in all Fieldpoint modules. I have to avoid this. The reason I have to record all timestamps is that sometimes two consecutive reads are the same in value and in timestamp; so even if I make sure I get a value every 100ms in my real time application I cannot trust that the shared variable engine will give a real new value every 100ms, because sometimes one read is the same as the previous one. My
understanding of the technology is that the cFP network interface checks for an
updated value of the channels of each module at the Advise Rate. If there’s a
new value the cFP transmits it to the Shared Variable Engine running in the PXI
controller, but if the value has not changed it doesn’t transmit anything, so
more efficiency is achieved in the network communication. This would explain the
timestamp behavior of the shared variables bound directly to Fieldpoint
channels; since there is no new value the shared variable is not updated so the
timestamp of two consecutive reads is the same.
2. Create a Modbus server and then create shared variables bound to the Modbus server channels. With this method any time my RT application asks for a new value the shared variable engine provides a real new value with an updated timestamp, and all timestamps in the same module are equivalent (in 1usec range). Therefore, it looks like using the Modbus solution I only have to record one timestamp per module.
So option 2 probably fixes my problem, but I'd like to understand why. Both methods use the shared variable engine, shouldn't they behave the same way? There's one downside in option 2, which is having to deal with Modbus addresses and not having the ease of use of option 1 that just browses to find the Fieldpoint channel.
Any comments?
A final note, it'd be great to be able to use the Fieldpoint VIs in LV Real-Time! Can this be achieved?
Raimon

Hi Raimon,
How are you binding to your shared variables? This KB reviews three methods:
http://digital.ni.com/public.nsf/allkb/FA610367EC62574186257118005089F2?OpenDocument
I don't believe using FieldPoint VIs on a PXI RT target is possible because FieldPoint is not a driver that you are able to install on the PXI RT target. We do have the cFP-2xxx line of RT controllers for FieldPoint, which can communicate directly to the FieldPoint modules, ensuring determinism.
Trey B
Applications Engineering
National Instruments

Shared Variable Deployment not accessible in Build Specification

Hi everyone,
I have a large project developed in LV 8.6.1 from which I executed numerous applications. I converted the project in LV 11 sp1f1, everything works well in code, everything is saved.
I wanted to build executable without cod change for LV 11 here is what I found:
Build the executable with Build Specifications inherited from LV 8.6 for which I checked on Use Labview 8.x file layout in Advanced. My application programmatically deploys all internal shared variables and when I wanted to access the Shared Variable Deployment in project in Build Specification then labview locked and I have to kill LV. Other time I did not access the Shared Variable Deployment and I start building executable when it looks the build progressing similar as in LV8.6 and last step before popping the attached error all the saved files in the build location were deleted.
I set up a build specification just for this LV 11. Again I wanted to access the Shared Variable Deployment and again labview is looping something from which I had to kill labview. I opened it again, I skipped the shared variable deployment line and I build the application. Because my application programmatically deploys shared variables I included in builder the lvlib where shared variables belong. The build files does not includes this time as output the file *.lvlib for which my inherited LV8.6 code programmatic deploys shared variables.
My question is should I change the code (very large code) taking out the programmatic variables deployment and to relay on the build executable to do deploy them then what should I do with Shared Variable Deployment line in Build Specification which for my large application is not accessible or is any way to still use the shared variable as in LV8.6 but for which I need *.lvlib in build location.
Another important issue: when I launched my application built as I showed in previous second case, first thing that I see is that my application is not able to save errors (I have a log file where I save different drivers or communication errors). Any idea why application even without shared variable deployed is not able to write a text file? I am administrator of my computer with all rights.
Thank you,
Virginia

No, I am not able to close Labview because of the windows error with only one button to close application. The application is correct executed. Next time when I start this project it is asking me if I want o recover even if I accept to recover it looks what I had last time it does not save.
For my application also I am building a VI without diagram built as source distribution for which I set in my builder this top vi and I excluded everything from the project because my application copies instances at the run time of this vi as many times as hardware modules I have in the system and also I have this vi included in my application (for the content of this vi). My vi contains interfaces for hardware configuration as well as drivers functions call for each hardware module I have to control in my application. Everything is good building this vi, but in less then one minute after the build is executed and build interface closes again I have the windows error which force me to close project. Next time when I open project I did not see the option to recover the project.
In the mean time I received second message and I wonder if you refer to files names or to folder names or all together. I checked and the maximum size is 122 characters in the vi paths.
Thank you,
Virginia

How can I change my Shared Variable from "I/O Variable" to "Network Published"

Hello,
I have an application that is using a series of NI wireless sensor nodes. I am trying to programmatically access shared variables. Right now the only method I have found to access the data from the shared variables is datasocket read. I am on labview 8.6.1 so I don't have as many shared variable options as newer versions of labview. I do think there is a way to access properties for the shared variables, but I'm not sure about how to change the nodes channel properties to "Network-Published". Do i need to remove the node from the project and bring it back in with the new settings? When i have done this in the past i have run into naming conflicts. I would appreciate any ligtht that can be shed on this issue that will help me create a vi that operates quicker.

Any Shared Variable that has “I/O Variable” for its Variable Type (see screenshot of the Shared Variable Properties below) refers to any channel of data (such as Analog Input or Output or Digital Input or Output) directly from a module channel. In other words, this is how you directly get the raw reading straight from (or to!) a specific module channel.
You cannot edit the Variable Type to Network Published. You can check “Enable Network Publishing” as above, which allows this Variable to be accessed from a VI on a Host VI. You could also create a separate Network-Published Shared Variable which you can wire directly to the I/O Variable on the Target VI if you wish.
Best,
Ryan C.
Applications Engineer
National Instruments

Shared Variable Initialization

For whatever reason if I use shared network variables over the network they take 20 seconds each to initialize... after all of them initialize they are very fast. Does anyone know why it would take exactly 20 seconds for this to occur? If i look at the variables in variable manager i can see the update values and they are exactly 20 seconds apart. This occurs weather i'm using a library with 20 variables or one with only 1 variable.

Hi Tak321,
You can change the gateway address in the network properties on Windows (if that is the operating system you are using), however, doing so could disrupt your communications to your building network. It does sound like it is possible that the shared variables are routing through the other network. You could try disabling that network adapter to be sure. It is also possible to bind shared variables to a specific network card: http://digital.ni.com/public.nsf/allkb/D358BABAE2F61F1A862571570056867D?OpenDocument
Regards,
Jeremy_B
Applications Engineer
National Instruments

Network shared variables lose binding

Hello,
I am developing an application in LabVIEW that uses network shared variables to transmit data between two PC's on the same subnet. The shared variables work fine when running the VI's in development mode, however, when i build the vi's into an executable I find that they no longer work. Here is what I have found so far:
I deploy the shared variable library on the publisher machine (also happens to be the development machine) through an invoke node in the executable. NI distributed system manager confirms that this does deploy and indeed updates as it should.
For the executable on the subscriber PC I created a second shared variable library (same project) with the same shared variables and bound them to the respective shared variables from the first library by selecting enable aliasing, then bind to PSP URL and browsing to the shared variable I wish to bind it to (e.g. \\hallnet-ellm2\shared variable library\serial Number). The machines listed under browse were listed by name so when I tried this initially and it did not work I manually changed the name of my machine in the URL box to the IP address of the publisher hoping that would fix it in case the subscriber could not resolve the publishers machine alias. So now my bind URL read \\192.168.0.1\shared variable library\serial Number.
As part of the executable on the subscriber I deploy this second shared variable library. NI distributed system manager confirms that this deploys but under quality for an individual variable it has a list of issues (see attached) and the bound variable is not updating. At this point the publisher shared variables are still functioning fine. By clicking on 'edit variable' I can see that the variable on the subscriber is still bound but the PSP URL is now \\localhost\shared variable library\serial number. Changing the PSP URL on the subscriber to \\192.168.0.1\shared variable library\serial number enables the variable to update as expected.However by this time my executable has already picked up the error and does not function.
I think that the issue lies with the bind URL used on the subscriber as for some reason it does not keep the binding configured in the project and instead changes to 'localhost'. Why is this? Should it not stay bound to the address specified in the project?
I have tried changing the IP addresses in the aliases file so that
[My Computer]
My Computer=localhost
becomes
[My Computer]
My Computer=ip of local machine
This did not help.
The shared variable libraries are included in the build spec to go into the support files directory and they are successfully deployed from there on both publisher and subscriber.
I am using LabVIEW 8.6 on Windows XP
Thanks for any help you may be able to offer,
Lee
Attachments:
distributed system manager.JPG ‏74 KB

Hi Lee,
I hope you are well. Thank you for your post. Your application sounds very interesting.
Looking at your issue I was wondering, have you tried lowering your firewalls, as this may be causing the problem.
Also, another option would be to setup a private network. Do you have access to any routers that you could use to link the two machines independent of your IT's infrastructure?
The other thing to try is two other computers entirely. Again, it would be ideal to take them off the network you are on, but it's something to try if my prior suggestion doesn't work. It should work on the original two machines though, and it's likely that different computers won't solve your problems because I suspect the network.
Remember that the client variables must know the location of the variables on the server, so you can't move the server exe around without changing this value.
Make sure to set the network location in the "Bind to Source" option for the client variables.
It is also possible to write a separate piece of code to install on every machine that is responsible for deploying the library and by doing so eliminate the need for programmatically deploying the variables in the original application. However, this won't really help you, because the variables you use in the application have to be the same as the ones deployed in the library, so if you change the library, they'll no longer be linked and they won't receive data. You'd have to create a separate exe for every binding source you wanted to link to, and then have a second, known library for the sake of communication locally on the computer between the ‘deployer’ and the actual application. The main application could then be assigned the responsibility of launching the correct ‘deployer’' if it sees it needs to switch to a different variable binding source. This method is not the most streamlined or effective, but it might work.
Just to let you know, you will need to use the DSC toolkit.
Please find below some knowledge base links that I think you will find helpful in your application.
Using Shared Variables in Executables
How do I Programmatically Change the Data Binding Source for Shared Variables?
I hope this information helps and if you can give these suggestions a go and let me know how you get on, that would be great.
Kind regards,
Prashant M
Applications Engineer
NI UK & Ireland

Programmatically redirect shared variables

I can programmatically change the data binding for a shared variable from (from on RT target to another) using method 1 as described here:
http://digital.ni.com/public.nsf/allkb/2E8BAD0EA218A7558625712E0003F044
However the change is only associated locally with the current VI, if I restart the VI or access the shared variable from a different VI it returns to the initial data binding as defined in the variable library. I have to change the binding each time a start a VI.
Is there a way to programmatically change the data binding in such a way that the change is persistent and shared between vi's?

Hi PESobol,
when you want to store changes you actually need to store them!
You can access shared variables programmatically using functions like "Open Variable connection". So you could load a text file with descriptions of your shared variables and connect to such a variable based on information of the text file. For me that seems like a better way of configuration than having to change and save VIs all the time…
Best regards,
GerdW
CLAD, using 2009SP1 + LV2011SP1 + LV2014SP1 on WinXP+Win7+cRIO
Kudos are welcome

Problem while binding variable progmatically shared variable in RT

Hi All,
I have a problem while programaticaly binding the shared variable from RT controller.
The application scenario is as follows
I have three cFP controllers and two
server PCs in my application. Servers are implemented with Redundancy. If server
1 fails, server 2 will take care and vice versa. The cFP controller program is
intelligent enough to detect this switching and identify the active server.
I am using shared variable
communication for transferring the data between cFP and Active Server. This I am
achieving by binding the cFP variable to Server variables. I can bind server
variables to cFP variables also. But I have some advantage with first one rather
than second one.
Now, cFP Variable to Server Variable
binding I can do in two ways.
Right click the variable in Project
Explorer and select the network URL.
Other method is by programmatic
binding.
Now Programatic binding should be
done in cFP controller since cFP controller should bind to second server
whenever it detects switching.
For this, I tried with
SharedVariableIO property node like in the below attached diagram 1.
But I was getting a deployment error
shown in attached diagram 2.
The second method I tried is by
transferring a shared variable library cFP Library.lvlib to cFP through FTP and
opening the Library variable reference and by using the variable property node.
This way of binding was successful when I run from windows PC. But in RT
controller, it was giving me Error 1 while opening a
library.
I am attaching the code with this post
Summary of the problem is I am not able to progmatically bind variables from
RT Controllers
Kindly help me in solving this
problem.
Regards,
Blackperl
Message Edited by blackperl on 08-18-2008 08:29 AM
Message Edited by blackperl on 08-18-2008 08:31 AM
Attachments:
Code and Library.zip ‏27 KB
Diagram 1.jpg ‏15 KB
Diagram 2.jpg ‏25 KB

Hi All,
I have a problem while programaticaly binding the shared variable from RT controller.
The application scenario is as follows
I have three cFP controllers and two
server PCs in my application. Servers are implemented with Redundancy. If server
1 fails, server 2 will take care and vice versa. The cFP controller program is
intelligent enough to detect this switching and identify the active server.
I am using shared variable
communication for transferring the data between cFP and Active Server. This I am
achieving by binding the cFP variable to Server variables. I can bind server
variables to cFP variables also. But I have some advantage with first one rather
than second one.
Now, cFP Variable to Server Variable
binding I can do in two ways.
Right click the variable in Project
Explorer and select the network URL.
Other method is by programmatic
binding.
Now Programatic binding should be
done in cFP controller since cFP controller should bind to second server
whenever it detects switching.
For this, I tried with
SharedVariableIO property node like in the below attached diagram 1.
But I was getting a deployment error
shown in attached diagram 2.
The second method I tried is by
transferring a shared variable library cFP Library.lvlib to cFP through FTP and
opening the Library variable reference and by using the variable property node.
This way of binding was successful when I run from windows PC. But in RT
controller, it was giving me Error 1 while opening a
library.
I am attaching the code with this post
Summary of the problem is I am not able to progmatically bind variables from
RT Controllers
Kindly help me in solving this
problem.
Regards,
Blackperl
Message Edited by blackperl on 08-18-2008 08:29 AM
Message Edited by blackperl on 08-18-2008 08:31 AM
Attachments:
Code and Library.zip ‏27 KB
Diagram 1.jpg ‏15 KB
Diagram 2.jpg ‏25 KB

Programmatically bind shared variable

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