How do you get multiple plots on a graph? LV 6.1

[Vr6Fidelity]

Ok I have this working now, thank you all very much.

I do have two questions remaining.

1. How do I make the graph scroll? So I can keep a constant number of points on the screen and have the old points scroll off the screen to the left?

2. There is a delay between when things actually happen in real life vs when they are displayed on the screen, its about 1 second. How do I fix that?

Also I changed the index numbers to make the right data go to the right indicators.

[smercurio_fc]

If you want a scrolling "graph" then you need to use a chart instead of a graph, as I mentioned before.

The delay you're seeing is probably due to the time it takes to simply draw the data on the screen. Depending on how much you have to draw, that delay will vary. Also, one technique that is used is to defer panel updates. However, I honestly don't remember if this is even available in 6.1. You should check the LabVIEW documentation.

[GerdW]

Hi Vr6,

1) keep only the last 512 (or any other number you want) samples in the shift register to have a "scroll left" effect for the graphs.

2) You have a 500ms wait in your loop and your DAQ surely needs some time too. This should be the reason for your 1s delay. Either lower the wait time or make the DAQ aquire less values at a time (decrease loop iteration time...).

[Vr6Fidelity]

How do I control the size of the shift register?

[GerdW]

Hi Vr6,

when array size exceeds your limit you simply use "array subset" to get only the latest samples...

[Vr6Fidelity]

Could you explain how I would use array subset? I tried using a array size to feed the inndex array, but it didnt take the 2 dimensional interger.

[GerdW]

Hi Vr6,

here you go:

The other, non-shown case is set to "0...255" and has just a wire connecting in- and output tunnel. Replace "255" by any number you like...
Or do the comparison before the case to allow for changing the "history size" at runtime.


Sorry, can't save to LV6.1 at home - you have to recreate the vi on your own

Message Edited by GerdW on 04-24-2008 10:12 PM

[Vr6Fidelity]

I see what you are trying to do there, but I just cant get it to work on my VI, I dont know how to deal with the 2 dimensional array going to the graph.

Can somebody please just help me out there, Ive been holding up testing for 2 days now trying to make this graph work, and im really starting to look like an idiot.

Please help.

[GerdW]

Hi Vr6,

here's my part of code included in your vi

Edited: some more cleanups and comments in the vi...


Message Edited by GerdW on 04-25-2008 03:51 PM

[Vr6Fidelity]

Ahh thank you Gerd. Its amazing how simple it looks.

It works great, thank you so much.

I still dont understand why the index inputs are not filled in. I am surprised that the correct way for it to work is blank. All this time I was trying to wire the size of the array into the index input.

Message Edited by Vr6Fidelity on 04-25-2008 09:18 AM