DSC VI won't connect to shared variable outside of project

My main VI will start up and connect to shared variable if I first have my project open. It will not connect to them if I try to run it by itself. I am deploying the library programmatically, but that doesn't seem to help.
Also, I can't get the main VI to run on startup.
Thanks

Hi Brian,
Thank you for the additional information. Let's put aside the run when opened issue and try to work on having your variables deploy and connect successfully.
When you run the VI within the project, are the variables successfully deployed as well?
Where are you seeing that the path to the library is blank? Where do you see that the data binding path for the variable in the working VI gets changed?
It would be quite useful for you to post a small example project, with one library, and we can tackle these questions individually, as with so many configurations (in project, not in project, running when opened, deploying successfully), I am having a little trouble keeping them straight.
Trying my best to help,
-Sam F, DAQ Marketing Manager
Learn about measuring temperature
Learn how to take voltage measurements
Learn how to measure current

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Migrating large project from DSC 7.1 to LabView 2009 Shared Variables ... What's the next step after recreating my variables?

I am in the process of migrating a large distributed (multi-workstation) automation system from the LabVIEW 7.11 DSCEngine on Windows XP to the LabVIEW 2009 Shared Variable Engine on Windows 7.
I have about 600 tags which represent data or IO states in a series of Opto22 instruments, accessible via their OptoOPCServer. There are another 150 memory tags which are used so the multiple workstations can trade requests and status information to coordinate motion and process sequencing. Only one workstation may be allowed to run the Opto22 server, because otherwise the Opto22 instruments are overwhelmed by the multiple communications requests; for simplicity, I'll refer to that workstation as the Opto22 gateway.
The LabVIEW 2009 migration tool was unable to properly migrate the Opto22 tags, but with some help from NI support (thank you, Jared!) and many days of pointing and clicking, I have successfully created a bound shared-variable library connecting to all the necessary data and IO. I've also created shared variables corresponding to the memory tags. All the variables have been deployed.
So far, so good. After much fighting with Windows 7 network location settings, I can open the Distributed System Manager on a second W7/LV2009 machine (I'll refer to it as the "remote" machine henceforth) and see the processes and all those variables on the Opto22 gateway workstation. I've also created a few variables on the remote workstation and confirmed that I can see them from the gateway workstation.
Now I need to be able to use (both read and write) the variables in VIs running on the remote workstation machine. (And by extension, on more remote workstations as I do the upgrade/migration).
I have succeeded in reading and writing them by creating a tag reader pointed at the URL for the process on the Opto22 gateway. I can see a way I could replace the old DSC tag reads and writes in my applications using this technique, but is this the right way to do this? Is this actually using the Shared Variable Engine, or is it actually using the DataSocket? I know for a fact that attempting to manipulate ~800 items via Datasocket will bog down the systems.
I had the impression that I should be able to create shared variables in my project on the remote workstation that link to those on the Opto22 gateway workstation. When, however, I try to browse to find the processes on that workstation, I get an error saying that isn't possible.
Am I on the right track with the tag reader? If not, is there some basic step I'm missing in trying to access the shared variables I created on the gateway workstation?
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Kevin Roche
Advisory Engineer/Scientist
Spintronics and Magnetoelectronics group
IBM Research Almaden

I have found the answer to part of my question -- an relatively easy way to create a "remote" library of shared variables that connect to the master library on my gateway workstation.
Export the variables from the master library as a csv file and copy that to the remote machine.
Open the file on the remote machine (in excel or the spreadsheet app of your choice) and (for safety's sake) immediately save it with a name marking it as the remote version.
Find the network path column (it was "U" in my file).
replace the path for each variable (which will be either a long file path or a blank, depending on the kind of variable) with \\machine\'process name'\variable name
where machine is the name or ip address of the master (gateway) workstation (I used the ip address to make sure it uses my dedicated automation ethernet network rather than our building-wide network)
and process name is the name of the process with the deployed variables visible in the Distributed System Manager on the gateway machine.
NOTE the single quotes around the process name; they are required.
The variable name is in the first ("A") column, so in Excel, I could do this for line 2 with the formula =CONCATENATE("\\machine\'process name'\",A2)
Once the formula worked on line 2, I could copy it into all the other lines.
Save the CSV file.
Import the CSV into the remote library to create the variables.
Note: at this point, if you attempt to deploy the variables, it will fail. The aliases are not quite set properly yet.
Open the properties for the first imported variable.
There is probably an error message at the bottom saying the alias is invalid.
In the alias section, you'll see it is set to "Project Variable" with the network path from step 4.
Change the setting to "PSP URL" with the same path and the error message should disappear.
Close the properties box, save the library, and then export the variables to a new CSV file.
Open the new CSV file in Excel, and scroll sideways to the NetworkrojectBound field.
You'll notice it is False for the first variable, and true for the rest. Set the field FALSE for all lines in the spreadsheet.
Scroll sideways... you'll notice there are two new columns between NetworkrojectPath and Network:UseBinding
The first one is NetworkingleWriter; it should already be FALSE for all lines.
The second one is Network:URL. That needs to be set equal to the value for each line of NetworkrojectPath.
You can accomplish this with a formula like in step 4. In Excel it was =U2 for line 2, and then cut and paste into all lines below it.
There is a third new field, Path, which should already be set to the location of the variable library. You don't need to do anything with it.
Save the edited CSV file.
Go back to the remote library, and import variables from the just-edited remote library CSV file.
Once you have imported them and the Multiple Variable Editor opens, click on done.
You should now be able to deploy the remote variable library without error. (Make sure to open the Distributed System Manager and start the local variable engine. It took me a few failures before I realized I had to do that before attempting a deployment).
Voila! You now have a "remote" library of shared variables that references all the shared variables on the master machine, and which should be deployable on other machines with very little difficulty.
It actually took longer to write out the process here than to perform these steps once I figured it out.
Kevin Roche
Advisory Engineer/Scientist
Spintronics and Magnetoelectronics group
IBM Research Almaden

On my windows 7 machine, itunes won't connect home sharing with apple tv

On my windows 7 machine, itunes won't connect home sharing with my apple tv. This problem started about two itunes updates ago. Any thoughts?

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Executable won't re-connect to shared variable engine when it breifly goes offline

Hi,
I have shared variables that are hosted on a field-point controller. I read these variables from executables that run on a PC. When the shared variable engine on the field point controller goes offline and then comes back online (for instance, if I cycle the power to the controller), the executables on the PC don't automatically reconnect. I need to restart the executables in order for them to re-connect and read the shared variables.
Any ideas on how to have the executables automatically re-connect? I don't want to have to restart the execuables when the power cycles on the controller,
Thanks, Derek.

Hi Derek,
It is my understanding that the variables should reconnect, even after your FieldPoint has been power cycled. I found a few articles that could be helpful; read through these and let me know if you are still having issues.
http://digital.ni.com/public.nsf/allkb/7BA64956A475405F862570ED007B2A88?OpenDocument
http://digital.ni.com/public.nsf/allkb/04D9A85B6967EE87862571140065EEC6?OpenDocument
http://digital.ni.com/public.nsf/allkb/AA97FF29D0B3C748862572F600055B22?OpenDocument
Cheers,
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NI Medical

Error connecting to shared variable OPC item

I have a DSC application that has a bunch of shared variables. Some of those variables are bound to an OPC server(Eurotherm). When I place controls or indicators in a VI and bind them to the shared variable, some of them get the "green light" and some of them get the "red light". If I hover over the red light, there is a message about an error connecting to the shared variable. However, all the values update and appear to be working correctly. Why would I get this error?

Hi Brian,
Which version of the DSC Module is this? Is the OPC Server that you are trying to connect to on your local machine or on a remote machine?
Have you tried deleting the front panel object and redragging it from the project explorer? What type of value is this (boolean, double, etc?)
What are you referring to when you mean an "identical instrument" - are you connection to two different OPC I/O servers in your projects?
Would you be able to post a screenshot of this error please?
Best regards,
-Sam F, DAQ Marketing Manager
Learn about measuring temperature
Learn how to take voltage measurements
Learn how to measure current

I am trying to connect Dashboard shared variables to a server on a different subnet. Any ideas?

My goal is to control a device that is connected to our wired network using an Android tablet via Dashboard. I have created a vi with shared variables that controls the device as expected when it runs on a computer that is connected to the same wired network. The problem is that my Android tablet running the Dashboard app cannot connect to the shared variables on the PC running the vi on the wired network.
Our wireless network is on a separate subnet from our wired network. I am able to ping my Android tablet from the PC on the wired network but when I try to connect a variable in Dashboard, the PC running the SVE cannot be found. I tried listing it in the alternative server settings window and it still did not work. The only way I have been able to get around this is to run the vi which launches the server on a laptop that is connected to the wireless network and the wired network at the same time. My tablet can then find the server and my VI can connect to the instrument that is connected to the wired network. The laptop is somehow acting as a bridge between the subnets. I need to find a way for the Dashboard app to connect directly to the PC on the wired network. My PC IP address is 192.168.0.105. My Android IP address is 192.168.10.93.

Data Dashboard doesn't care about subnets, but it has to be able to access the server using the right ports. There is probably a firewall blocking the shared variable ports. This document explains how to configure a firewall to allow shared variables to be accessed. Your challenge will probably be to figure out where the firewall is and how to configure it.
It is also possible that the router that your Android device is connected to doesn't know how to route to the other network. Again, that is an issue with your router that you need to resolve.

CRIO and ni 9234 modules not working or communicating through fpga with accelerometers, fpga connected to real time application which is also connected to shared variables linked to modbus slave

Hi,
I have a compact rio which has a 4 way chassis attached to that chassis is three ni9234 modules they are linked using fpga to a real time application then using shared variables in the low speed loop that are linked to a modbus slave to communicate with dcs, the ni 9234's have accelerometers connected to them with iepe ac coupled option on the c modules, my problem is the real time application seems to be running okay even when power loss occurs it restarts with no problem and the fpga writes to the portable hard drive bin files fine but without a accelerometer connected I get low noise readings as soon as I connect a accelerometer to any one of the 10 outputs it just goes to a fixed number (0.03125) as soon as disconnect it again it reverts back to reading noise, I have run a scan on the modules and only get a spike when I connect or disconnect the accelerometer, I have tested the voltage at the pins of the module and I get 22 volts dc which makes it more likely that the hardware is not the problem but a software is maybe causing this to hang-up, I attach project and files for your perusal. I also carried out a new project which in scan mode directly linked the module input to shared variable and the same scenerio again. Help would be much appretiated.
Many thanks
Jason
Solved!
Go to Solution.
Attachments:
logger 2plusmodbus2.zip ‏679 KB

Whren using waveform acquisition with the 9234s we recommend the following FPGA and RT template.
http://sine.ni.com/nips/cds/view/p/lang/en/nid/209114
it can be extended as a data logger with:
http://zone.ni.com/devzone/cda/epd/p/id/6388
or using shared variables combined with scan engine
http://zone.ni.com/devzone/cda/tut/p/id/9851
The FPGA in all of these, as well as the RT framework have been used successfully by 1000s of users. I would recommend giving these a try.
Preston Johnson
Principal Sales Engineer
Condition Monitoring Systems
Vibration Analyst III - www.vibinst.org, www.mobiusinstitute.com
National Instruments
[email protected]
www.ni.com/mcm
www.ni.com/soundandvibration
www.ni.com/biganalogdata
512-683-5444

How you connect a shared variable between internet?

Hello;
I have a aplicarían which use the shared variables, and other one which is the slave. both work rightly, in a local lan, but now I need connect the slave aplication between Internet.
what is the procedure?????
thanks in advance

Hola Joju,
La tecnología de variables compartidas sólo es válida dentro de una red local. Si necesitas acceder a una variable desde Internet, tendrías que hacer uso de DataSocket y de servidores DNS.
Servidores DNS para que tu PC tenga asociado un dominio en Internet y, de esta forma, se pueda acceder a él a través de su nombre. El problema es que tendrías que dar de alta dicho dominio. Después, seguir las instrucciones de este link, cambiando direcciones IP por nombres de equipo:
How to Use Shared Variables and DataSockets to Pass Data Between Two Networked PCs
Esto no es trivial y dependiendo de la configuración de la red del operador, es posible que haya problemas. Para comunicación a través de la red, siempre es más recomendable utilizar funciones básicas de TCP/IP o servicios web.
Un saludo,

DSC - Event triggering for Single Process Shared Variables

Hello,
I understand how to set up a Value Change Notification for Network Published Shared Variables so that an event will trigger when that particular Shared Variable changes. However, I can't figure out how to do the same for Single Process Shared Variables. Is this even possible? Can someone shine a light on this, please?
Thanks in advance.
- James Pham
Solved!
Go to Solution.

VRspace4,
Hello! It is not possible to enable alarming for Single Process Shared Variables. A workaround to setup a Value Change Notification would be to create a network shared variable that reads from your Single Process Variable, but at that point in time it might be worth just replacing your variable with a networked shared variable.
Ben Sisney
FlexRIO V&V Engineer
National Instruments

My iPad Videos App Won't Connect to Shared Library

When I launch the iPad Videos app, then tap on "Shared" and then tap on my library, all I get is a spinning circle.
Admittedly, I do have a large iTunes library, but it shouldn't take this long to load. (Actually, I dont know how long it takes to load, because it has never loaded. I've waited as long as 20 minutes thus far).
The strange thing is that my 3rd-party Air Video app works every time, all the time. Why doesn't the Apple Videos app?
Update: Waited a little longer this time, only to get this error message: "Unable to turn on Home Sharing"

I find that closing iTunes and the Videos App on my iPad Air does not solve the problem.
Even this solution, if it worked would drive me bonkers. If I wanted to go to my computer I could just watch the video there. If I wanted to watch the video on my Apple TV I would go watch it there.
Why is it that my Apple TV always flawlessly connects to my shared iTunes library, but my iPad Air never will? The fact that it works on Apple TV suggests the problem in not my network, my router, my firewall, etc. It suggests there is a bug with the apps on the iPad.
I too have resigned myself to the fact that AirVideo is the answer. Sadly though, this doesn't solve my problem with trying to listen to my music library.
I have the exact same experience with my iPhone 5c. I'm a huge fan of Apple products for several years now after being a detractor. I am simply left with the feeling that this issue, reported by many users, with many different devices, is not getting the attention it deserves.
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ITunes won't connect to shared library

Hi,
I have OS Lion and updated iTunes.
I shared an iTunes library on a NAS - Thecus N3200.
In iTunes I see the library under SHARED (as I should, I guess).
When I click on it, it starts loading, but eject by itself after some time.
I did hear years ago that NAS iTunes server is not working anymore.
Anybody knows anything about that?
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Tadej

You should contact the company the makes the NAS you are using. The problem, if there is one, is with the NAS. Have you checked their web site for software updates that might address the problem?

How to deploy Shared Variables with aliases (Project Variable), when some machines are offline?

Hi all,
I have a distributed application (PC + a few CompactRIOs). My PC contains variables that have aliasing enabled -- they are bound to variables on the cRIOs.
One of the cRIOs is currently offline. I'm trying to deploy some changes I've made on the PC side. Unfortunately, LabVIEW refuses to deploy my PC libraries, because it can't connect to the cRIO that the variables are bound to.
How can I bypass that check, and force my PC to update? (I don't see why it's compulsory for the cRIO to be online for this :-/)
Thanks in advance!
Solved!
Go to Solution.

Thanks for responding, Esteban!
To answer your questions:
No error codes. The deployment dialog just says, "Failed to connect to Real-Time target". That's expected, because the cRIO is not connected to the network.
I'm binding simple numeric types only.
The cRIO has been taken offline for maintenance. I'd like to update my PC .lvlib files, and test some modified PC code, but I can't because LabVIEW won't let me deploy my PC libraries or run the VIs if it can't find the cRIO. (Here's another common use case: I'm developing software before I've received my hardware, and would like to test my VIs without a cRIO connected)
I've attached a minimal example (LV 2012 SP1). I have a VI on the PC that plots data from the cRIO, and processes local data. I'm trying to run the PC VI when the cRIO is offline.
Expected outcome: The VI should run, and "PC Output" should change according to "PC Input". "cRIO Output" should have a default value, and the PSP LED should be red -- mousing over the LED should say "Bad Quality".
Actual outcome: LabVIEW refuses to run the VI completely, saying "Failed to connect to Real-Time target".
Attachments:
Project Vars.zip ‏10 KB

I want to Host my Shared Variables on a cRIO, but use DSC for Logging/Alarming/SCADA

Hi everyone,
What I'm trying to do is this:
-Host shared variables on my RT targets (cRIO-9022) for reliability
-Use the DSC module to log to database, track Alarms, develop distributed HMI
The problem I'm running into is that the DSC engine (it seems) needs the shared variables it is monitoring to be hosted on that computer. The DSC engine can not run on a real-time target.
My end goal is to create a plant-wide network of cRIO's that are all linked back to a central server/PC that runs DSC to collect and stores data in a database. The plant HMI would also connect to the central server and get their information from there (not directly connected to the cRIO process). Is this possible/does any one have ideas on how to do this efficiently?
Thanks for the help.
--CLD--
LV 6.1, 8.6.1, 2011 SP1, 2012 SP1
Solved!
Go to Solution.

Sachsm,
Thanks for the input. I tried to create a test project for this type of architecture (bound NSV's) but am running into some errors.
I have attached a screenshot of the project and front panel showing the binding status of each variable **see attached picture**
Hosted on PC:
-Clone (Variable1) ---- This is bound to Variable1 on cRIo using the "Create Bound Variables" option in the Library
-Variable3
Hosted on cRIO
-Variable1
As you can see, when I drag variable 1 directly onto the PC front panel, the variable connects (indicator is green). Likewise, when I host Variable3 on the PC and drag it to the front panel, it connects. However, when I drag the Clone (variable bound to Variable1 on cRIO) onto the front panel, it cannot connect. Any thoughts?
--CLD--
LV 6.1, 8.6.1, 2011 SP1, 2012 SP1
Attachments:
Binding Error.jpg ‏127 KB

Shared Variables Won't Update

Hello All -
I'm having a problem interacting with my OPC server, and I'm hoping some suggestions will help me out here.
I have an OPC server running on a XP SP2 machine, and it is interacting properly with my equipment (a bioreactor). When I use the NI OPC Quick Client, I can browse to the tags I want to see, and those tags update as expected. I can put my hands on the temperature sensor and watch the output change on the QuickClient screen. The only odd thing that I have to do with the Quick Client is that I have to manually set the data type (Float, Single, Double, etc.) and request an asynchronous read before it will begin updating.
When I try to connect via Shared Variables, it's a different story. I create the shared variable using the instructions at the bottom of this page:
http://digital.ni.com/public.nsf/allkb/EA15F53DB6FECCA5862567240064DF09
Next, I drag the variable to my front panel and start the VI. A summary of the behavior is this:
* As long as the variable type is read/write, the LED is green on the VI.
* I can write values to the OPC server
* The VI never shows data arriving from the OPC server, I can only write.
* No error messages are received.
This behavior doesn't change for any permutation of "read/write" status in the variable definition, switching the node from read to write, changing the control from read to write, etc.
I'm using Labview Developer Suite 8.6 with the DCS option. Fresh install of Windows and LV. No other software on the machine.
Any ideas how to troubleshoot this? I'm running out of ideas...
One other update, which may or may not be related: Whenever I try to connect using a DataSocket method via one of the example VIs such as "Monitor Multiple OPC items.vi", LabView crashes immediately.
Message Edited by wdmarner on 10-06-2008 10:56 AM
Message Edited by wdmarner on 10-06-2008 10:57 AM

Hi Wdmarner,
When you configure OPC CLient I/O Server, what server are you using? The NIOPCServers or the Varable Engine or something else? With respect to datasockets, does the system hang or does it crash and totally exit labview?
Regards,
National Instruments
RIO Embedded Hardware PSE
CompactRIO Developers Guide

Front Panel binding of shared variables very slow initialization / start

Hello @ all,
I am using a server running Windows2000 and LV 8 DSC RTS for datalogging. All shared variables are deployed on that server.
I am now facing the problem, that all front panels running on the clients using the network shared variables on the server take very long to sync on startup. First the flags on the controls bind to the shared variables turn red, after up to ten minutes they start to turn green. The panels use up to 40 controls bind to the shared variables.
All firewalls are turned off. I tried to connect the client to the same switch the server is connected to. Same problem. Does anybody have a clue?
Thx for your quick answers.
Carsten

While I can't offer any solution to your problem, I am having a similar issue running LV8.0 and shared variables on my block diagram (no DSC installed).
When using network published shared variables, it takes anywhere from 30 sec to 4 min from the vi start for any updates to be seen. Given enough time, they will all update normally, however this 4 minute time lag is somewhat troublesome.
I have confirmed the issue to be present when running the shared variable engine on windows and RT platforms, with exactly the same results.
In my case, the worst offenders are a couple of double precision arrays (4 elements each). They will normally exhibit similar "spurty" behavior on startup, and eventually work their way up to continuous and normal update rates. Interestingly enough there are no errors generated by the shared variables on the block diagram.

DSC VI won't connect to shared variable outside of project

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