Remote panels - Client Crashes Situation

[Raul.Ionel]

Hello,

I would like to ask if someone can help me with the following situation.

I have an application which contains a top level VI and several other dialog VIs. This application can be accessed by a remote client via Remote Panels. From the top level VI (contains the menu - while loop and event structure) the client selects what he want to run. Then the front panel of his choice opens on his computer. It all runs ok.

However, if the client computer suddenly loses internet connectivity, then the Run Time Engine reports a plugin crash in the browser.

On the server side, all opened apps seem to freeze. I can turn them off one by one and then restart everything again.

Could anyone let me know how to approach this issue? I would like the client, in case a crash happens, to be able to reconnect to the application.

Thank you and have a nice day.

[Tarek]

Hi,

I would be glad to help you with this.

I will need to know what version of LabVIEW you're using? Which web browser? and OS?

You're not supposed to get a crash when you lose internet connection, only a "Remote panel connection is closed" notification on your web browser, and a page refresh usually re-establishes connection with the server. Can you please post the exact crash message here?

The Server side VIs freeze because they are still under the control of the remote client. In order to unfreeze them you need to gain back control by right clicking the main VI front panel and select Regain Control.

Hope this helps.

[Raul.Ionel]

Hello and thank you for the reply,

On the server side I am using Labview2011 with SP1, under WinXP.

On the client computer, Run Time Engine 2011, Chrome under WinXP.

The server is situated in a laboratory and it should work on its own, 24/7, without my intervention for taking control of the app.

So now, I have considered the scenario when a client connects to the application, starts running it and after a while he will use the Windows Task Manager to end the application, without considering the normal options which are available in the menu. In this case, in the browser I would get Image1. Basically the client will have to connect again to the server. On the server side, I have inserted a state where I check to see if there are any remote clients connected to my application. If no client are connected, then it closes. So as the client kills the task, imediatelly my server stops the application. So this is solved and works fine.

The second scenario is when a client does not close the application even when his time allocation has reached 0 minutes. Again, the server checks this time limit and it closes the client connection. For this, I have used in a case, the code presented as Image2. If this situation occurs, the client is disconnected and he
gets the Image 3 message on the browser. This error appears twice and each time the client presses Continue. In the end the server takes control and it is all ok.

However, what might cause this error? Is there a chance to fix it? I couldn't find any reference to it and the Remote Panels.

Thank you and have a nice day.

[Tarek · Accepted solution]

Hi,

Thank you for attaching the screenshots.

The reason why you're getting this error is because you're trying to close a connection that is already closed by the server. You can add a simple error handler after your Close Connection to Client block, that should take care of the pop-up. There is a way to ignore this error (or any other). This knowledge base article does a great job explaining how.

Please let me know if this answers your question.

[Raul.Ionel]

Hello and thank you,

I managed to solve the situation as you indicated.

Have a nice day.