Read Time Channel from TDMS file and error -2525

[Joe_Gerhardstein]

Have a TDMS file (attached) and am trying to read a Time channel from it in LV 8.2 (see attached VI, based upon the example VI "TDMS - Read data (event).vi").  I can open the TDMS in DIAdem and see the Time channel, and DIAdem recognizes it as a Time channel.  However, when I try to read it as an array of TimeStamps in LabVIEW, I get the -2525 (data could not be converted into the specified data type).

Oddly, I can read the Time channel as an array of DBL, and the numbers that are returned are increasing in size, but will not convert to TimeStamp, either.


Any ideas?

[MikeS81]

Hi Joe,

i think it is not possible in this way, bacause LabView and Diadem work with different timestamps. LabView work with the 1 January 1904 12.00 am and Diadem work with 01.01.0000. I think you can read it as double and convert it.

Mike

[Joe_Gerhardstein]

Thanks.  I tried opening the TDMS file with the LabVIEW TDMS File Viewer VI, and it won't read the time stamps correctly, either.

[Herbert Engels]

The data type of the timestamp values in your file is floating point, not time stamp. If you store the values as time stamps, as shown in the "TDMS Write Data (Events)" example, they will show up properly in LabVIEW and DIAdem.
Herbert

[Joe_Gerhardstein]

Well, that's what I thought, too, but it doesn't always work.  See attached image (tdmswrite.gif) of how I am writing the time stamps.  I'm using the "t0" from a waveform (generated via DAQmx) as my time stamp source instead of Get Date/Time in Seconds as done in the example VI, but a time stamp is a time stamp so it shouldn't matter.

The odd thing about this is that DIAdem correctly recognizes the channel as Time (diadem.gif), but LabVIEW thinks it is DBL.

I've looked through all the properties for this channel and for the channel created with the "TDMS Write Data (events)" example VI in DIAdem, but cannot see any differences.

[Eli_S]

Hi,

I have been looking at your code and I cannot determine what is the problem. Can you post the TDMS writing VI as well?

[Joe_Gerhardstein]

I can't get the TDMS writing VI to reproduce the problem any longer.  The TDMS file I attached earlier in this thread is the only one I have that has this problem.

I'll keep a look out and see if I can figure out what I did to make that file special.