RT Remote panel indicator refresh stalls

[viSci]

I understand that an RT application is headless (i.e. does not have a front panel) for that reason it makes sense to check when a client connection is made and then enable writing to any front panel indicators. What is mysterious to me is that if you do update a some indicator values before any remote connection is made, then that indicator may 'stall'. In other words subsequent updates, even if forced via property value nodes or local variables does not visually update on the remote panel. Could anyone offer a theory to explain this? I have observed this in LV 8.2.1

Thanks,

Mike Sachs

Intelligent Systems

[Neville D]

QUOTE(sachsm @ Nov 5 2007, 12:57 PM)

In other words subsequent updates, even if forced via property value nodes or local variables does not visually update on the remote panel. Could anyone offer a theory to explain this? I have observed this in LV 8.2.1

Thanks,

Mike Sachs

Intelligent Systems

I don't think value property or local variables (as relating to updating the front panel) works with RT. In general I try to avoid property nodes when working with RT.

I usually just keep updating the indicators even if there is no client connection; when there is one, everything updates normally.

Are you using any exotic indicators (IMAQ image display)?

Neville.

[Ashish Uttarwar]

QUOTE(sachsm @ Nov 5 2007, 12:57 PM)

.....subsequent updates, even if forced via property value nodes or local variables does not visually update on the remote panel...

I experienced problem with Property Node on RT system. But, Local Variables worked for me!

I wonder if you are running any kind of "Timed" loop. Did you try running the loop slower (~500 milli sec) interval?

--- Ashish

[viSci]

QUOTE(Neville D @ Nov 5 2007, 04:21 PM)

I don't think value property (as relating to updating the front panel) works with RT. Even if it works, it will be slow. In general I try to avoid property nodes when working with RT.

I usually just keep updating the indicators even if there is no client connection; when there is one, everything updates normally.

Are you using any exotic indicators (IMAQ image display)?

Neville.

Yes I am using an exotic IMAQ image display and those seem to be the most problematic. In regards to value property nodes, there is an NI app note that specifically suggests doing this. http://digital.ni.com/public.nsf/allkb/FC5...6256C8C0054689B

[Neville D]

QUOTE(sachsm @ Nov 5 2007, 02:37 PM)

Yes I am using an exotic IMAQ image display and those seem to be the most problematic. In regards to value property nodes, there is an NI app note that specifically suggests doing this. http://digital.ni.com/public.nsf/allkb/FC5...6256C8C0054689B

Viewing the IMAQ image display has always been immensely problematic.. it seems with every upgrade of Vision, the remote display either works or if it had been working previously, stops working.

What version of IMAQ/Vision are you using?

I think with 8.2.1 and Vision 8.5 the display didn't seem to work, but with Vision 8.5 and LV 8.5 it works fine. I use it without bothering to check the value changed stuff. It seems to work without causing any serious performance issues. I did notice that if the images update rapidly, the remote display might miss updating (since this might be handled by the lower priority Web Server task on the remote machine).

Prior to that, with older versions of Vision the bug re-appeared.

LV 8.2.1 + Vision 8.2.1 ->bug

As far as I can remember, with Vision 7.1. and LV 7.1.1 it worked.. but I could be wrong.

If you really want bullet proof image display, you will have to compress the image using JPEG Encode and Decode VI's (found on NI's website), transmit it using either your own TCP IP routines or shared variable, and display on the Host (Client) side using additional code.

Note that the JPEG Decode VI has a memory leak bug, but that is a story for another day.

Neville.