Front Panel Hangs when Image is Requested From WebServer

[xkenneth]

All,

I've got a big LabVIEW project, and I made a couple extra VIs in order to be able to access some of my data visually over http. The extra VIs are setup behind the LabVIEW webserver, and whenever a request is made, all of my front panels hang. Is this normal behaviour? Can I correct this somehow? Are my programming patterns correct for what I'm trying to accomplish? Thanks for your time.

- Ken 

[Bakk_Diagram]

Hey Ken,

I would need more information about what you are doing before I could answer your questions.  Are you using remote panels to view the data.  If so are you using "Embedded" remote panels.  When the remote panel is able to control the VI, then only one computer can have control at a time.  This would appear to "hang" your front panel on the computer that doesn;t have control. You can right click the front panel andclick "request control", or you can make the remote pane l"Monitor" type instead of "Embedded" type.

[xkenneth]

Chris,

    No, as the control mechanism isn't cross browser. I'm simply serving out a static image. In fact, I'm not even hitting a document being server out of the WWW root. I'm simply hitting the .snap url for my VI.

Regards,

Ken 

[NathanK]

Ken,

Your panels hanging when you request a snapshot is not normal behavior. What version of LV are you using? Do you see this behavior with any VI or just with your application?

On a side note- you said "as the control mechanism isn't cross browser" Are you referring to the remote panel control mechanism? Remote panels are supported on IE, Netscape derivatives including firefox, and safari. They also work in Google Chrome although that is not officially supported. Only if you use opera are you out of luck.

Nathan

[xkenneth]

Nathan,

That's neat, it's been a while since I used that functionality. I'll try using another VI, but this is the second time I've tried to use NIs webserver and it always hangs. I'm using LabVIEW8.5 at the moment.

- Ken 

[Bakk_Diagram]

Hi Ken,

Are you using any other webservers on that computer. You might want to try a different port.  You can configure this in the WebServer configuration in Tools->Options.

[LUX_]

Anyone has solution for this problem yet?

I have the same issue that when I open the browser to view my application's remote panel, my original front panel hangs.

The browser is view only that do not take over any control.

I found out that when I run the browser to view the front panel, in the windows task manager, it actually runs two copies of my application.

The application is built with Labview 8.0.

[The_Chancenator]

Hi Lux,

Which setting on remote front panels are you using (monitor, embedded, or snapshot)?  And when you say hang, are you seeing the remote front panel updating in the browser and not on the host computer?  Or are you just unable to interact with the user interface on the host computer?  When a remote user requests control of the remote front panel, the host computer won't allow any one else to use it.  Also, is this an executable?

Cheers, 

[LUX_]

Thanks Marti for your reply.

The application is a real simple temperature monitor. It is a snapshot of the screen and the user from remote site can only view the front panel.

It is a exe. when the remote front panel displays in the browser, the front panel on the server hang and became white screen. The browser can still see the front panel but not respone to the signal change (Or respones to the signal with a long delay.)

In the windows task manager, you can see there are two temperature monitor application exist. 

Thanks!

[The_Chancenator]

Hi LUX,

If you would like the user to see updates of the front panel, you should use the "Monitor" option, rather than the Snapshot.  Snapshot will just display one static image of the VI; Monitor will update the front panel.  Users cannot gain control with the monitor option.  

Also, the fact that two instances are running is expected behavior with remote front panels. 

Regards,