"alarm and event display" crashes my application

[Witek]

Dear All,

I use the "alarm and event disply.vi" in my DSC application. It works fine: I can acknowledge alarms, events etc. BUT...

When I double click the alarm item (or press Alt-Enter) and watch the alarm properties in the Alarm Properties dialog, I can usually watch the properties for some time, selecting the next or previous alarm item, but most often than not, my application just crashes. I don't get any LabVIEW error dialogs. Only Windows is telling me that the application stopped working and it just closes giving me no explanation. Sometimes I don't even see the Windows message. 

I've tried this on two different computers... same boat!

I'm using:

- LV2011

- Windows 7

In my application I create the shared variables programmatically, set alarm thresholds programmatically etc.

Anybody had the same problem?

regards

Witold Nocon

[Norbert_B.]

Hi Witek,

I'd like to ask you to check the following example project: Help / Find Examples... / Toolkits and Modules / Datalogging and Supervisory Control / Applications / Boiler.lvproj

Just to see if this does the same when you are trying to see the alarm properties.

Thanks for the cooperation,

norbi

[Witek]

Well.. The Boiler example works fine.

What I do, is that I create everything programmatically:

-          I create the databases programmatically

-          I create the process with it’s shared variables programmatically (according to a configuration information)

-          I return the references (and names) for those shared variables

-          I use a couple of loops for different communication protocols to gather data and each loop sends this data to the “data processing loop”

-          This “data processing loop” receives those values and writes those values to the appropriate shared variables.

-          To update numerical indicators on the panel I just read the shared variables programmatically (using reference) and also read the alarm information to change the colors of the indicators for alarms.

It all works fine. Data is stored in databases. I can see and ACK the alarms. I write user alarms, I write events. See everything in this display.

Just this alarm and event display that crashes when I look at the properties (it takes using the “Next” and “Previous” buttons a couple of times). See the picture with the error...

Any quick ideas?

My option now is not to use this Alarm and Event Display control and write my own "control" that wil display the alarm and I will programmatically ACK them...

I will also try to pinpoin the error, but currently run out of ideas.

[Witek]

Anyway....my current guess now is that I should not use the "Alarm and Event Display" and read the alarm information at the same time.

I thought that maybe reading alarm thresholds using the SV property node and using this display at the same time might create problems, but disabling the SV property node, I have the same problem all the time...

😞

[Witek]

Well…I think I have isolated the problem, and I have recreated it in the Boiler example. Here’s what’s happening:

If you watch the properties of the alarm in the Alarm and Event Display, and if this alarm “disappears” at this time, the application will crash. This will happen for example when this variable is set to AUTO ACK.

You can try setting the R02 pump to zero. This will cause the L01 level  to increase reporting an alarm. Now if you set the flows so that the level start decreasing (I set the outflow to max, and the inflow tozero), and immediately click the HI HI alarm and watch it’s properties, the application will crash at the time when this alarm is cleared due to the decreasing level  (AUTO ACK).

It also seems a “little non-deterministic” but this may be my own impression.

Anybody had a similar problem or is able to recreate it?

[Norbert_B.]

Hi Witek,

Thank You for the detailed explanation of your problem and for reporting this issue.

It seems that you might have found a bug. I have reported this to the LabVIEW developers, and hopefully the issue will be fixed in a future release.

I apologize for any inconvenience this caused for you.

In the meantime, you mentioned that you have found a workaround for this problem. Can you use that solution for now? Can I help you with working out something else?

Best Regards,

Norbert

[Roy_F]

For future reference, the CAR Norbert filed for this problem is 370238.

Roy