export waveform graph data

[jade.swordy]

Hi all,

What I have is a LabView program that retrieves the following data from a Keithley (for characterising electronic devices): IV Characteristic, Voltage vs. Time, and Current vs. Time. The IV Characteristic data is exported to a data file directly using the Write to GPIB Function with the data coming directly from the Keithley, however the latter two I had to parse from the IV data and plot separately against a clock. The problem is the only way I could plot it was using a Waveform Graph with the data, time and t0 and now I am not sure how or if I can export this data to a simple text file like I did with the IV characteristic.

I have tried to convert to dynamic data and use the function that exports to Excel but that is also proving to be problematic. I would prefer to export to a text file as this is the easiest format for me to further plot the data in IGOR. If needed I can attach the necessary VI's and thanks for any help.

-J

[GerdW]

Hi jade,

when dealing with waveform you should use functions from the waveform functions palette - rather then looking into ExpressVIs!

Use WriteToSpreadsheetFile with the Y component of your waveform. Or don't use waveforms at all, the graph also plots arrays of values (as shown in its context help).

And please post your VI so we can comment on the problems you tried to describe!

[jade.swordy]

Thanks for the reply!

But I would really rather have the data written to a text file.

I've attached my VI, and the subVI necessary to run it. On the 8th page of the above structure is how I am graphing and exporting data. I am having trouble using the Write to Measurement File operation (plus, I really do not like to use this utility as it is).  In the bottom right hand corner of this page is where the IV data is being exported and I'd really love to be able to do the same with my V vs. Time and I vs. Time data.

Any help you can give would be so appreciated! This VI is an edit I am doing on someone else's and I am just not well-versed enough in LabView to emulate their programming style.

Thanks!

[K_Joy]

Hi jade.swordy, 

You can use Write to Spreadsheet File to write to a text file, just wire a .txt file path into the file path input. I am not able to see the VIs you said you attached, but I hope this information is helpful to you.

Regards,

Kelsey Johnson

National Instruments 

[jade.swordy]

Here are the VI's, hopefully they attach this time. If there is any way to save the voltage and current data the same as the IV characteristic that would be great, it's just that once it goes throughthe data parsing utility it doesn't seem like there is any function that accepts the new type of data.

[K_Joy]

Hi jade.swordy,

In the two VIs that you attached, I can’t find where you are trying to write data to a file or what that data is! The Data Parsing Utility does write a 2-d array (which is not labeled) to a text file and outputs 1d and 2d arrays which could also be written to a file in the same way. I don’t see anything labeled IV, voltage, or current or anything being plotted to a graph. Where is the voltage vs time and current vs time data that you are trying to write to a file? If I can see it, then I might be able to help you with how to write it to a file. 🙂

There really shouldn’t be anything complicated about writing data to a text file...Are you able to get a text file, but it’s not in the format that you want? Or are you not able to print to a text file at all? You said there isn’t a function that accepts the new data type—what data type is it?

Kelsey Johnson

Applications Engineering

National Instruments