What causes the Shared Variable Engine to Crash?

[RGSchmidt]

All,

Some background info:

I am using the SVE and DSC so that I can log my data to Citadel using Data Sets. I converted a previous DSC 7.1 project that used the tag engine over. That app ran for over 18 months. Need to upgrade app and add features at my customer requests so we migrated to LV 8.0.1.

I have an app that crashes the Shared Variable Engine (SVE). I created a test app with a single SV and then created a control and bound it to the SV and it works every time until I launch the larger app. The main app only has 33 SV that are set when I receive TCP data from PXI RT system (not using SV on RT since the logged data is only a fraction of the total data streamed and I don't want to take apart the RT data and send the SV separately). I have bound front panels controls to the SV's. When I run, I get server connection has been closed. I verified that the SVE was running with the test app before launching the main app.

I deploy the shared variables in the application and have verified they are deployed by the Monitor Variables utility ... but it always shows "No Value" for the data fields. I have set logging to enabled for data only, set Value Deaband (%) to 0 and Value resolution to 0, Update Deadband is Disabled as is Alarming, Scaling, Initial Value and Description. Security is set to default. All of the variables are set to Double, Network-Published, Single Writer with Buffering and Bind to Source disabled.

I have verified that the SV deploy without error by clicking Deploy from the project. Autodeploy All is off but I get the same results with it On (checked).

I undeploy and kill the process when I close the application.

I have tried only using 1 or 2 of the SV in the main app but get the same results. Every once in a blue moon it will work after rebooting the PC (but not everytime). Once it dies I have tried running NI examples as well as the test app and they fail until I reboot.

The error code indicates that the SVE engine has crashed. I have changed the service settings on Windows to relaunch on 1st, 2nd and all times after but nothing restarts the SVE. After it crashes it is impossible to exit LabVIEW without it hanging or reboot the PC without pressing the hard On/Off switch.

Once it dies there is nothing that I can do to get it back alive without rebooting the PC (a real problem for a control and monitoring system).

Any ideas would be greatly appreciated

Thanks.

Randy

[Paul M.]

Randy,

These types of crashes are hard to track down.

Do you have access to LabVIEW 8.20?  There are a few issues with the shared variable engine that have been fixed in this release and it may solve this particular crash.

If not, let me know and we'll explore some other options (including trying to replicate it here at NI).

[RGSchmidt]

Hi Paul,

I have access to 8.20 but not for RT or DSC. My customer Wyle Labs will be contacting NI since they have SSP and should have received the new CDs but still haven't.

Another thing that happened is that the test app that has a control that writes to a SV and an indicator that is bound to the SV now only runs about 50% of the time without crashing the SVE.

I upgraded everything (LV, DSC and RT) from 7.1 to 8.0 to 8.0.1. Is there a possibility that I have an old DLL or library? I would hate to have to rebuild the machine from scratch (XP SP2 + LV) but will if there are any known problems in upgrading liking I have.

Thanks.

Randy

[Paul M.]

Randy

Sorry for the delay, I've been researching your issue and juggling a few other issues. 🙂  One thing we can check is the Windows Event Log which will give us some more details as to WHY the Shared Variable engine seems to be blowing up on us (Conttrol Panel -> Administrative Tools -> Event Viewer).  Any details in there along the lines of Variable Engine or Tagger crashing will help us narrow down what's going on.

There's always a possibility of files not getting upgraded correctly; however there aren't many shared components between LV 7.1 and LV 8.0. The Shared Variable engine is entirely new and the installations of LabVIEW themselves don't share many files outside of the example finder and a few other small common components (things located in the appropriately named Shared folder)  I keep both on my machine (in addition to 5.1, 6.1, 7.0, and 8.2) without any hiccups.

The SVE crashing I have seen in the past (and from internal bug reports) has been from buggered installs, so uninstalling and reinstalling DSC may be a good course of action. One good test to do in the middle is to see if the engine still crashes with DSC uninstalled. 

Hope this helps.

[RGSchmidt]

Hi,

I was able to get LV 8.2 including DSC and RT installed and it seems to have fixed the problem. I was able to successfully launch applications around 20 times with no failures.

I noticed when installing RT SW that the SVE went from 1.0 to 1.2, I don't know if there was a version 1.1.

Also, I did a clean install of LV 8.0.1 on another machine (w/o DSC) and had no problems with the SVE but since I wanted logging to Citadel plus historical and security I need DSC. Have not added DSC to this install but upgraded to 8.2. I should have put in DSC but didn't think about it until after I installed 8.2 (goofy me).

Thanks for your help.

[Paul M.]

RGSchmidt,

Glad that 8.2 solved your problem.  As a side note, you can have both 8.0 and 8.2 running concurrently on a machine and thus DSC 8.2 and 8.0 as well.

[RGSchmidt]

Hi Paul,

I have 7.1, 8.0 and 8.2 on all machines except the one where I was trying to see what it would take to fix the SVE. I also have 5.1 loaded on one of the machines.

Thanks.

Randy