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

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Message Edited by Ben S on 10-01-2009 06:05 PM
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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.
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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?
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Kind regards,
Prashant M
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Attachments:
properties.JPG ‏34 KB
method.JPG ‏18 KB

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Attachments:
Screenshot-5.png ‏108 KB

Found the buffering... disabling it solved the problem... thanks.
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Attachments:
Screenshot-6.png ‏110 KB

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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
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National Instruments

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Wendy,
I am afraid Semaphores are not network-shared objects (to my knowledge), they are system-level objects that use operating-system synchronization mechanisms. If I were synchronizing on a single machine, a semaphore might be a valid mechanism; as an aside, most user-mode semaphores are designed to synchronize within a single process - to synchronize between processes you need to store the semaphore in the Kernel, and to synchronize over a network you would need a network node to handle serialization of requests. My Shared Variable is published over a network, and to my knowledge there are no network-published synchronization mechanisms available - mostly because there is no way to currently perform an atomic test-and-set on the Shared Variable (am I correct?) and there isn't a mechanism for blocking access to a Shared Variable from another network device/machine (or is there?). I've been looking for some way to implement an atomic test-and-set but I am running into a wall; I know that if I select the "single writer" attribute of the Shared Variable I can get LabVIEW to force a single writer allowing me to have an atomic "set", but I need more than that.
If only there was a network-shared Semaphore or some way to block other network accesses to the Shared Variable I would be in business - something like what I want doesn't exist, does it?
Thanks!
-Danny
Message Edited by texasdiaz on 02-23-2006 02:52 AM

Problem while binding variable progmatically shared variable in RT

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