TestStand Event 13 - UIMsg_StartInteractiveExecution is not captured by LV Operator Interface

[SAS]

Hi All,

We have developed a customized OI in LV 7.0. We have registered few callback events to get the UI message from TestStand 3.0 and display it in the OI.

We are facing one issue- that is, Randomly the LV 7.0 OI doesnt capture the TestStand UI message, "UIMsg_StartInteractiveExecution- Event 13". Most of the time, the OI runs fine. But randomly it couldnt€™t get the event 13. After that, all the following events (like DisplaySequenceFile, EndExecution) are not captured. Because of this, the OI is hanging and we have to kill the process.

We came to know about the event 13 not getting captured by logging the UI message events for both proper and improper running conditions.

We are sure that the TestStand is sending the message, but then LV only could not capture it. When we run the source code of the OI, we can terminate the hanging OI by Pressing "Abort execution". Now, if we re-run the OI again, we can see the test reports getting displayed without starting the test. Those test reports were from the tests which were initiated during the previous run of the OI). We suppose, due to some reason the OI could not get any of the messages from TestStand, but then TestStand is running the test sequence in a separate thread and keeps on sending the messages.

Let me give the flow of execution:
1. Scan for the module
2. Find appropriate Test Sequence and display the test steps
3. Select the necessary steps for execution
4. Run the Selected Steps

The OI hangs after pressing Run Selected Steps Button. The OI hanging is occurring mostly the first time after the application is started. If the first time the OI runs fine, then all the consecutive execution also runs fine (most of the time).

I could not send the code as it is quite. Any help is really appreciated as this is one of the crucial bugs, which the customer is very particular about.Sorry for the big message

Thank you,
Sasi

[Aaron B.]

Hello Sasi,

I imagine that you are capturing the events by handling the UIMessage Event. We (myself and two other Engineers) were not able to replicate the problem that you are seeing. When you say that LabVIEW does not capture an event, do you mean that you do not ever see it in the log you make or that you do see it in the log but it does not get handled by your code the way it should be? I would recommend setting a conditional probe in the event handler that pauses whenever an event 13 is generated to see if what exactly happens in the code. Other than this debugging advice, there is little we are able to determine without being able to replicate the error. I would also try to figure out what conditions are different between executions that demonstrate this behavior and ones that do not. There must be something different between the two for them to behave differently.

Regards,

Aaron B.
National Instruments

[SAS]

Hi Aaron,

Thank you for your reply.

One of my colleagues has given me the following link," Message link" which i feel is related to our OI hanging issue. Can you please inform me whether you have any solutions for the issue highlighted in that link?

I can send you our application code itself, but it is around 18 MB. Is there anyway, we can send you the code and get your inputs on our issue?

Thank you,
Sasi

[Aaron B.]

Hello Sasi,

I spoke with the author of that discussion forum (luckily she is still in our AE department). She suggested that I point you to a KnowledgeBase concerning ActiveX callbacks in LabVIEW; however, this KB is internal only. So here is the copied text of the article:

"Title:
Why Doesn't LabVIEW See the ActiveX Events for Some of My ActiveX Objects?


Problem:
I am trying to use an ActiveX object in LabVIEW. I can successfully create an Automation Refnum for my object class. But if I try to create an ActiveX event queue, I get an error 95. The explanation is "Event Queue could not be created. Make sure the event exists and the name is spelled correctly." I know the event exists, and I'm sure that I am spelling it correctly. I used the "List Event Descriptions" VI, but it came up empty. What am I doing wrong?


Solution :
LabVIEW currently gets its event information from the IProvideClassInfo interface. The interface must be correctly implemented by the object for events to be seen by LabVIEW."

I personally did not find this terribly enlightening, but maybe it will help. Have you experimented with the suggestions that I gave you in my first posting? Do you get the same errors when you run our shipped OI examples? Please let us know what your debugging has revealed and feel free to email your code if you are at a dead end. Just make sure if you do that we will be able to open and run it without having to make any modifications at all (or if we will have to, please give step-by-step instructions concerning what needs to be done). Please list what steps we need to take to replicate the error, identifying what you believe the incorrect behavior is and how we can determine that it is happening by running the code with your instructions.

Regards,

Aaron B.
National Instruments

[SAS]

Hi Aaron,

Thanks again for your detailed inputs. I tried to simplify the code to send to NI for support. But then, surprisingly the simplified code didnt give me the issue. so now i am in the process of identifying which section is causing the bug.

If i identify that, then i think that we can able to solve it easily.

Regards,
Sasi