time with 'Write to measurement file'

[duf]

Hello,

I am making an acquisition waveform. The integration time is 1s divided in 128 samples. When I execute the software, the datas are stored in a text file with 'Write to measurement file'. This text file is a continuous list of 128 numbers-packs in rows.

I want to add the time column (date+hour+minutes+secondes+1/10sec+1/100sec) in front of each number acquired. (And not only in front of the first number of the 128 package)

I have don t know how to add this.

Can you help me?

Thanks a lot.

(See file attached)

[Dennis_Knutson]

You should try Export Waveform to Spreadsheet File instead of Write to LabVIEW Measurement File. The default behavior of Export Waveform is to record an absolute date/time string and not relative time. In my version (7.1), I had to modify the subVI Waveform Time to Date Time String in order to record fractions of a second.

[EdDickens]

Also, in the setup dialog for the Write Measurement File, there's an option to include an "X Column Value" that normally holds a timestamp.

Enable one of these options and any included timestamp in your waveform will go into this column. If you don't have a waveform, you can build an extra column in your array of data points with the needed timestamp and it will work the same.

Ed

Message Edited by Ed Dickens on 02-20-2007 03:37 PM

[duf]

Indeed, I noticed the option of adding a X column for the time. But I don t know in which input of the 'write and measurement file' icon to link my time stamp to. If it has to be linked to 'signal', it s not the right format.... I guess it s not a comment either...

[EdDickens]

Your main problem is that you are actually losing the timestamps when you do the FFT on the waveform. The FFT outputs frequency information instead of time information.

I've modified your test VI slightly to record both the FFT and original Waveform and included a frequency and timestamp column. Does this give you the info you need?

Ed

[duf]

I added a time stamp that I linked to my signal (supposed to appear as a first column in the text file). I put a string to scale converter in between, to adapt to the format.

Of course, this might be the wrong icon: in the text file, the first column is added but no time displayed.

Do you have something to suggest? I am a bit lost cause no experienced...

Thank you. 

[duf]

Thank you, sorry for my last answer, we were writing at the same time.

The problem is that I can t open the file you sent because I have the version 8.0, which is older than yours.

I am trying to work it out, I let you know.

[EdDickens]

Sorry about that.

Here's an 8.0 version.

[duf]

I changed the path name and created a new text.lvm in my folder.

When I open it, it loads a numerous amount of things, and at the end, the program can t be executed, because of a mistake in the 'write to measurement file' parameters.

Isn t there a simpliest way to add a time stamp as shown in the attached folder (instead of what  I ve put)?

[duf]

To precise what is happening when I want to open the VI: there is a window asking to 'Find the control named Ex_userDefProperty.ctl' and it continues loading only when I click 'Cancel'.

So then I assume that I probably forgot to create a folder or something... I don t have a clue about what it is.

Do you have an explanation?

Thanks a lot