Converting data file from TDMS to TXT - time format and headers.

[sts123]

I have this .vi that converts the .TDMS to ASCII. However at the moment the time format is "00:00.000001    5.2041    0.2388    -0.0004    0.9106" for each line.

How can I make it in seconds in scientific format so the data will show as "1e-6    5.2041    0.2388    -0.0004    0.9106"?

Also how can the headers be added into the ASCII file?

to_Asci_2.viFetching info...

[Francois Normandin]

@sts123 You can explore the String palette where you will find an array of string formatting nodes. 

The simplest for you is to replace the date/time string with Format into string, and configure for scientific number.

[sts123]

  On 6/18/2025 at 2:55 PM, Francois Normandin said:

@sts123 You can explore the String palette where you will find an array of string formatting nodes. 

The simplest for you is to replace the date/time string with Format into string, and configure for scientific number.

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I tired using Format into string, but then the result text file includes time stamp 4 times for each line of data, instead of doing just once.  

[cordm]

If the time appears for each channel, then you didn't set the loop tunnel mode to last value.

[sts123]

Not sure what that is. Can you please guide me?

[cordm]

First search result for "labview loop tunnel mode":

Auto-Indexing Tunnels with For Loops and While Loops in LabVIEW

In your case:

[sts123]

  On 6/25/2025 at 6:24 AM, cordm said:

First search result for "labview loop tunnel mode":

Auto-Indexing Tunnels with For Loops and While Loops in LabVIEW

In your case:

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This worked as intended.

Many thanks.

 

[sts123]

Any thoughts how can I add header to the file, that are the same name as channels names in the Task?

[cordm]

Use Get Waveform Attribute (Waveform>>Get Attribute) to read the NI_ChannelName string attribute from each waveform. Add another loop before the first one where you get it from each waveform and then write it to the file.

DAQmx creates that attribute automatically. This is what Waveform Graphs use for plot names.

[sts123]

  On 6/27/2025 at 6:31 AM, cordm said:

Use Get Waveform Attribute (Waveform>>Get Attribute) to read the NI_ChannelName string attribute from each waveform. Add another loop before the first one where you get it from each waveform and then write it to the file.

DAQmx creates that attribute automatically. This is what Waveform Graphs use for plot names.

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It does not throw the names as expected.

to_Asci_3_range_2.viFetching info...

[cordm]

right-click the node, select "help" and read the manual, please

why use a while loop? use an auto-indexing for loop!

Edited June 27 by cordm