reading from graph to text file in labview 7.0

[PWard]

Hi Guys!
I am doing a project which reads analog values from a microprocessor board and I am using the Labview example Cont Acq&Graph Voltage-Int Clk.vi. I am getting an analogue graph using this VI. is there any way I can convert the values on the graph and save them to a text file?

Any help would be much appreciated!

Thanks
Pauline

[becktho]

Hi Pauline

There are several solutions, depending on the information you want to store in your txt-file.
An easy way is to use the "Export Waveform to Spreadsheet File.vi" (located in the palette int Waveform >> Waveform File I/O.

Hope this helps.

Thomas

[PWard]

Thanks for your response!
How can I use the Export Waveform to Spreadsheet File.vi if I am already using the Cont Acq&Graph Voltage-Int Clk.vi to generate the waveforms. Is there a way of connecting the two VI's?

Thanks,
Pauline

[becktho]

Hi Pauline

There are two ways. Either you place the Export vi in the vi you're already using or you assign the waveform indicator to a terminal (search the LV help for terminal). This makes the waveform-data available for other vi's if you use the Cont...vi as a sub-vi. This means you can create a new vi, place the cont acq&graph valtage-int clk.vi and the export waveform to spreadsheet file.vi in it and wire these together (similar to all the vi's in con acq&graph...vi).

Thomas

[PWard]

How exactly do I connect the two VI's. I have never used labview before so i dont know where to start.
Can I just copy and paste the waveform vi? How do i then connect up the two vi's?

[becktho]

Hi Pauline

If you don't know how to connect vis, search in the LV help for this phrase: Wiring Block Diagram Objects Manually

Hope this helps.

Thomas

[Lilly N]

Hi Pauline,

The "Export Waveform to Spreadsheet File.vi" is probably the best way to write the data to a text file. I have made a simple example of this to show what to wire to the "Export Waveform to Spreadsheet File.vi" to get you started. I have done this by generating a sine wave, and writing the values to a text file.

Hope this helps,

Lilly
National Instruments

[Lilly N]

Hi Pauline,

I forgot to save the example back to version 7.0, so here is the version 7.0 one.

Regards

Lilly
National Instruments UK