Discussion of Web Servers for Remote Front Panels

[brent99]

I've been working over the web server with remote front panel feature quite a bit this week and have experienced some interesting issues. I'm using 8.0.1 for the record. I have licensing issues but since I'm actively working with NI on resolving these, I'll refrain from commenting. Rest assured, if I did comment, the &%^&*%& keys on my keyboard would be getting quite a workout.

The biggest problem I've experienced (aside from the one I'm not commenting on) is that Remote Panel:Lock Control/Unlock Control property of the VI doesn't seem to work at all programmatically. I've tried to exercise this proprety a 1000 ways and it seems to do absolutely nothing. I'm wondering if this could be an 8.0 bug given that they renamed this property recently, but don't have the desire to explore this theory with version 7. The other two properties Client Connections and Close Client Connection seem to work fine.

I don't see a way to dictate which client has control when dealing with multiple clients. This is unfortunate because it would be a nice feature. I suppose if you were to edit the html a little to get client VIs to always request connections repeatedly and then have the server unlock connections with the Unlock property (assuming it worked) until the "right" client connected, that would accomplish that task but its a little bit roundabout. There's a "Client has control" message that appears and gets a bit annoying. I'd rather prefer there was just something in the bottom left corner signifying control. (Well, actually there is...haha)

I notice when you deploy a web server application, there doesn't seem to be a way to get the ini file to generate with the "WebServer.Enabled=True" property set and i end up manually editting that ini file a lot. I'm sure there is someway to get it to stick but haven't achieved that yet. It wouldn't surprise me if a lot of people had trouble getting this feature to work for this very reason.

I have found it possible to "launch" your VI out of the web browser container. For a large VI that takes up most of the screen, this may be desirable. A benefit I see of this approach vs. other remote deployment is that the code is still "server centric", meaning that you can update your code on the server to be accessed through the browser without having to update the clients individually. In fact, that's probably the best argument I see for remote front panels vs. other internet data sharing communication methods that are available through Labview.

Anyway, pretty cool feature overall. Doesn't seem like many people have used it too extensively but, although not without its limitations and certainly a pretty bandwidth heavy distributed approach, its certainly a fun and powerful feature of labview. And once you get past the licensing issues and get the general idea of it, its a pretty easy feature to leverage from existing applications. Java eat your heart out? Hmmm....