Variable Manager + All values are X

[Taylor_647]

Hi,

I am running an application on a computer using LabVIEW Run-Time built on a different computer using LabVIEW Development 8.5.1. The computer with LV 8.5.1 Development uses an OPC server to read tags from a PLC and store them in a database. On the computer with Run-Time I have a PCI-6033E device. The analog signals from this device are also read into the database on the computer with 8.5.1 Development using DAQ-mx Global virtual channels. The application on the Run-Time machine reads values from the database and displays them on the screen.

In the variable manager on the Development machine I can view the values both from the PLC and from the PCI device. The PLC variables are bound to tags from the OPC server and the PCI variables are bound to the Global Channels from the Run-Time machine. In the variable manager on the Run-Time machine I read the same variables bound to the same sources.

Problem:

After running the application for approximately 5 minutes (it varies every time) the variable manager on the development machine stops working. The quality of the variables still read as "good" but the values do not change. If I then clear the watchlist add the same variables back to the watch list every attribute (value, type, timestamp, quality, error code) is represented with an X instead of a number or word. On the Run-Time machine, the values of the PCI variables still update and work as expected, and the PLC variables (from development computer) become: value - not known, quality - bad, etc. To me, this indicates the problem is with the variable engine/manager on the development machine, since the manager on the Run-Time machine works as expected.

I'm wondering if there is a quick fix to this problem such as installing/uninstalling/re-installing some products or a setting that I should change. If not I guess the problem is in my application.

Any suggestions would be great.

Thanks,

Taylor

[Sappster]

Hi Taylor,

How are you hosting the Shared Variables, are they hosted on the development computer? Here is a common troubleshooting article for shared variables:

http://digital.ni.com/public.nsf/websearch/6E37AC5435E44F9F862570D2005FEF25?OpenDocument

Have you tried any other setups or different computers? Or tried hosting the variable in a different location?

[Taylor_647]

Hi Mark,

The variables bound to the tags from the PLC are hosted on the development computer. I will look through the article you sent.

Thanks for the help,

Taylor

[Juan G]

Hello Taylor,

Have you experienced the same problem with the variable managers getting the the SV values as X? I would like to know if you have been able to reproduce this issue.

Regards,

Juan Galindo
Applications Engineering
National Instruments

[Taylor_647]

Hi Juan

Yes, I am still having the same problem. It seems to happen whenever the program is repeatedly obtaining data from the Citadel database for an extended period of time. For example, if I leave the program un-updated with old database data displayed on the chart, the variables manager continues to update values and appears to be working fine. However, if I read data from the database (once per second) and display an updating XY-graph on the front panel, then after a while (5-10 minutes, usually) all shared variable attributes in the watch list become "X."

Also, I am not sure if this is a related problem, but when I have this problem with the shared variable manager my application also freezes. To unfreeze the program it must be stopped and then restarted, unlike the variable manager which only begins working again when the computer is restarted.

Thanks for your help,

Taylor Dean

[Sappster]

Hi Taylor,

I would like to try and reproduce the issue and find a way to fix it. Can you provide everything I would need to repeat this issue, like the database and programs calling the shared variables.

Thanks,

[Taylor_647]

Hi Mark,

I'm sorry I don't exactly understand what you need. Would you like me to send you the database (folder?, text file?), or do you just need the information about it (i.e. which computer it is on, name, lifespan, etc.)? I am logging the data to the Citadel 5 Database on the machine with LabVIEW development 8.5.1 and reading the data from a different computer running the application. I can send the VI/application as well if that is what you are looking for. Sorry again for not quite grasping your question.

Thanks,

Taylor

[Sappster]

Hi Taylor,

I'd like to get everything I would need to be able to see the issue on my computer. So if I get your VI can I run it from my computer and connect to the same database you are connecting to? If not, can you provide a database file that I could host on a computer here and reproduce the error you are receiving?

It might help if you eliminate as much of your program that doesn't effect the error and then send me the most simplified version.

Can you eliminate the database connection and just use basic shared variables hosted on the computer or target and get the same result?

[Taylor_647]

Hi Mark,

Sorry for taking so long to get back to you. The problem has actually be resolved. I think what happened was I did not have the correct server selected in the SQL server services manager window. For some reason specifically stating the computer name along with the database "\CITADEL" has fixed the problem (not really sure why, but it has been running for a few days now problem free).

Thanks again for all your help,

Taylor

[mbtoday]

I'm having a similar issue - Variable Manager shows all "X" and a blank Error Code for some shared variables, and good values for others.  Front panel controls bound to the shared variables show green and red statuses but they all work, even the red ones.  Unfortunately hovering the mouse over the red status LEDs doesn't work since the error message flashes on and off too fast to read.

I haven't touched any Citadel/SQL Server settings.  Could you please elaborate just a bit more about how you "add the computer name to the SQL Service Manager" - which menu, which field?

Thanks,

Mike