Working Principle of Remote Panel

[Alan Cheuk]

Hello,

I am using LabVIEW Remote Panel and want to know more about it. Does anyone know what is the working principle of it? How can it embeds a VI interface into a Web page? What technique and protocol are used in it?

Thanks

[tst]

I don't really work with the remote FP feature, but as far as I know, the monitor option probably just takes the image and passes it along and the embedded option requires that you install the RTE and (in windows, anyway) uses ActiveX to allow you to see LV native controls.

[Philip_Courtois]

Hi Alan,

It would take a couple of pages to describe how the Remote Front Panels work in LabVIEW, so here are a couple of links that describe how Remote Front Panels work:

Developing Remote Front Panel LabVIEW Applications

Remote Front Panels (presentation) 

Take a look at these links and let me know if you have any further questions, thanks.

[Alan Cheuk]

Hi Philip,

Thanks for you help. I have some questions after reading the information.

Firstly, do you know what is the technology used in Remote Panel to send the interface of a VI to a Web browser? Is it the Web Server continue to send the snapshot of a VI to the Web Browser?

Besides, what is the technology used to transfer the control (remote user's actions under remote control) back to the VI running in the server?

Moreover, what protocol is used for communication?

Regards,
Alan

[Philip_Courtois]

Hi Alan,

You have three options when creating a Web page with the "Web Publishing Tool"; Snapshot, Monitor and Embedded. Snapshot and Monitor are simply including an image of the front panel in the HTML document, whereas Embedded actually embeds a VI front panel (not block diagram/code) with all its functionality in the HTML document to remote control the actual VI on the server. The technology used for the remote control communication is provided by the LabVIEW Runtime Engine. That is why the Runtime Engine has to be installed on the client machines to be able to see the Remote Panel.

When accessing the HTML document the first time, the front panel will be downloaded. After that point, only data that goes to and from the controls and indicators will be transferred. Since the image of the front panel is not repeatedly being transferred, you will get a much better result. One thing you have to take into account though, is that ALL data to and from the controls and indicators is being transferred through the TCP/IP connection, so if you are transferring a lot of data (for example one million points every second on a graph), your network connection can get flooded. Therefore, don't update the indicators with an amount of data that exceeds what can be shown on the indicator.

Does this make sense?