Slave display with different screen..

[MogaRaghu]

In many instances of machine applications where LV is used the PC monitor is the primary ( and only) display.

But there are also many sensor DPMs ( digital panel meters ) which are provided for user convenience. And there is a problem here - never do the values displayed by LV match with that of the DPMs! Both are within 0.05 or so but still not the same.

Also is the fact that I need to find a place to fix these DPMs . All in all there needs to be a more elegant solution.

I was thinking of another 15" LCD monitor that can be made to show only the DPM values in a tabular format and the input for this monitor SHOULD come from LV and must the same as shown on the primary monitor. Maybe a shared variable can be used for this ?? If I use the same variable to update the value in primary as well as the slave montior, then the issue of variance is eliminated.

Question is : Can LV be made to drive two different monitors with different screen images at the same time ? Is there any plug in hardware that can help do this ?

Any ideas are most welcome.

Thanks

Raghunathan

[johnsold]

You do not need a shared variable, wires will work fine. Create a subVI containing the DPM displays and position it to show on the second monitor. Details may vary with OS and video drivers. Feed the same data to both displays. The only time you will see any differences are when the data is changing and one screen may update at a slightly different time from the other. Using the Defer Panel updates property might help reduce that if it was objectionable.

You could even expand the main GUI VI to cover both screens, but that might be difficult to manage if monitors change.

Lynn

[chrisger]

hi there

i think the DPMs use some kind of filtering and/or hysteresis to avoid flickering effects, thats why the values differ from the actual value. i'd try to find out how these filters work and then redraw them in LV or enable filtering in the DPMs.

the second monitor: well, that's not a  question about LV, it's about the OS. WinXP is able to support two monitors. then you can place a single frontpanel on each monitor (i.e. you have a single app with two FPs: one of them shows the filtered "DPM" - data). you can place the FPs on the two monitors using property nodes for the origins pixel coordinates.

[MogaRaghu]

Thanks.

I think I should have searched with the term " using two monitors" and I never would have started this thread !

Anyway thanks for your patient and helpful replies.

I got the point on stars. And you got them ;-))

Raghunathan

[MogaRaghu]

Hello Johnsold,

I think I need some more help.

I have managed to configure two monitors on my laptop with the other monitor as a clone. My laptop LCD panel is the primary display.

I am enclsoing a small sample VI in which I want to display the Guage only on the secondary monitor. I quite don't get how to do that ??

thanks for the assistance. ( I am using LV8.0)

Raghunathan.

Message Edited by Raghunathan on 08-02-2007 02:45 AM

[TCPlomp]

You shouldn't clone your display.
Have a look at this code

Ton

[johnsold]

Raghunathan,

Create a subVI which contains a copy of the Gauge. Set the VI properties to Show Front Panel When Loaded. You can manually position the VI onto the second monitor or use property nodes to position and size it.

I have enclosed a simple example. The Guage on the subVI is a Control, but it has been disabled so the user cannot change it by clicking on it. Open the Master file first. The Gauge file should open automatically.

Lynn

[MogaRaghu]

Dear Johnsold,

Yeah I have made some progress. But not got to the end still.

- Put the secondary monitor in DualView  ( independent configuration )
- Edit the VI properties of the MaxValGauge. vi  to run in the secondary monitor

With all of the above I ran the MaxValMaster.VI. Immediatley the MaxValGauge also was launched and I could move it with my mouse "into the second monitor " So far so good.

I stopped the main VI and then was surprised to see that the MaxValGauge.vi vanish from the second monitor and worse still the needle shrinked and the markings vanished ( I do not know how that happens ).See the attached image.

I thought once manually positioned and stopped, LV will remember the position. But it is not so I think. Maybe I need to programmatically set the bounds as given in an example in this thread. In the meanwhile I would like to know why the needle got disfigured so badly ...?

Thanks

Raghunathan

Message Edited by Raghunathan on 08-03-2007 06:58 AM

[johnsold]

Raghunathan,

I think I have seen other people report something similar to your shrinking gauge problem. Try searching the Forum archives for Gauge or Knob Resizing.

Lynn

[MogaRaghu]

Dear John,

I am not clear as to why one should create a gauge as a control to make it as a sub-vi ? For the intended function we need it as an indicator only.

Of course I tried to create a sub-vi with the gauge  as an indicator. But could not. Why ??

Thanks

Raghunathan