References being lost when passed to Actors

[maynej1]

So in an attempt to scale my application the same error started to occur with the TestStand actor (no modification to the TestStand actor was made).  I looked at the LabVIEW OI examples with TestStand and the top level vi's preferred execution system is "user interface".   All the subvi's in these examples I looked at were set to "same as caller". 

Unfortunately, I don't think the top level actor core.vi can be set to "user interface" and have it only apply to the TestStand actor (please correct me if I'm wrong).  So, I have two TestStand actor VI's set to a preferred execution system of "user interface".  One vi calls TestStand's "loginonstart" and the "Start" method.  The other calls the "Shutdown" method.

When doing this TestStand appears to start up correctly every time.  Ok, everything looks good so far...

The TestStand Shutdown method doesn't appear to be doing anything.   I monitor the existance of a process in task manager called TSAutoMgr.  Not too sure if this is a good way to determine if TS is running or not.  For the fun of it I registered a callback VI to ExitApplication event (like the example OI's do) just to see if the event is generated.  Nothing...

I'm stumped...  😞

I will leave this error alone for a while in hope someone comes along with a suggestion.  Perhaps I can ask for help in a TestStand/LabVIEW community...  For now I have to get the rest of my app running.

[Al.B]

Hi Maynej,

In your shutdown code, be sure that you are closing any open references to the TestStand engine in addition to calling the shutdown method.  I checked to verify with the simple OI example, and the TSautomgr process does remain loaded until the engine reference is closed.  However, I'm not sure why you arent seeing the shutdown event.  In what VI did you register for the event?

I also noticed that in your implementation attached previously, you are calling the shuddown method repeatedly until it returns true.  I would not recommend this as this will often lead to calling the method many times, and we expect for it to be called once.

If this is not the issue, a couple things to try:

1. as in your testing before, does the shutdown method work properly when you call the TestStand VIs directly rather than with the setup you are using now?

2. Please send the newest TestStand code you are using so I can take a look.

[maynej1]

Sorry for taking long to reply. My hard drive went bye-bye (no data could be recovered) and it took me a few days to get my computer back...

Attached is my distribution.

Background:

• Every lvlib is an actor grouped with its messages.
• Main.vi starts everything.

I stopped calling shutdown multiple times and changed it to how I typically do it. 

This version DOES start and stop teststand correctly BUT there is a 500ms delay in between the UI controller launch and the teststand actor launch.  If this delay is taken away I start to get errors saying the app mgr reference is invalid. 

This version has all executions systems set to "same as caller".  I tried changing the execution systems to mimic the example UI's, but it would only make things worse (i.e. LabVIEW would lockup and would not respond immediately after teststand was started).  I tried many scenarios with the execution systems with the startup and shutdown VI's.  Nothing really worked.

The only way I could get it to become stable was to put a delay between the launching of the UI controller and teststand controller (look in the actor core.vi of the MainController_Actor.lvclass).  I do not want to keep this delay in here...

Picture of how my actors are launched...

 

[Al.B]

Hi maynej,

Thanks for your patience as I look into this.  Let me summarize what I have found so far.  It appears that the error occurs in the case that the TestStand actor is called before the General and Batch Views are initialized.  When I added synchronization to ensure that the following code executed before the TestStand UI actor was called, I did not see the error (bad practice I know, but helpful in debugging).

I'm not sure why this is occurring, but it does clarify the cause of the issue. I'll keep looking into this and let you know if I find anything.

LVB/AristosQueue, any thoughts on why this might be occurring?

[maynej1]

Thanks AI.B for looking at the code.  I am seeing the same dependency. 

I have implemented messages to let me know when the TestStand front end callback has completed executing.  I used these messages to trigger my main controller to launch the UI controller.  So in effect my UI actors did not get launched until teststand was up and running.  Teststand starts, login is displayed, the close execution event is generated from front end callback, and my UI actors are launched. BUT... This caused the LV UI  to not act correctly.  LV buttons were not disabled/enabled properly (even though I traced the code and saw them execute without error) and some of the activeX callback VI's (From teststand events) I had implemented were never ran.

I simply switched it back to ensure the UI was launched BEFORE teststand....and everything works as expected. 

Weird...