Error 2525 with Read From Measurement File

[ni_curious]

Hi,

I'm getting this error using the LabVIEW "Read from Measurement File" Express VI on a TMDS file written with the LabVIEW "Write to Measurement File" Express VI.  The message dialog associated with the error reads as follows:

"Error -2525 occurred at Read From Measurement File -> ReadTMS_File.vi

Possible reason(s):

LabVIEW:  TDMS file data could not be converted into the specified data type."

I've attached the portion of my VI relevant to the TMDS file creation and writing and also I've attached the VI that I threw together to access the data.  The file was written from a continual waveform/data acquisition of NI_Scope (Immediate Trigger). 

I'm sort of amazed (actually, I'm not as I've come to expect this sort of thing with LabVIEW) that the complimentary VI to the one that created and wrote the file can't read it back. 

Anyone have any ideas why this error is occuring?

Roger

[Devin_K]

Hi Roger,

I believe the problem you are running into is due to a known issue with the TDMS Express VIs.

A workaround would be to use the TDMS file VIs located on the Functions palette at Programming >> File I/O >> TDM Streaming.  To write a file, drop down a TDMS Open, a TDMS Erite, and a TDMS Close.  Wire the waveform from your scope read to the data input of the TDMS Write VI.  If you want a pop-up dialog for the user, you can use the File Dialog Express VI located at Programming >> File I/O >> Adv File Functions.

To read from the file, use the TDMS Open, TDMS Read, and TDMS Close VIs.  By default the TDMS Read returns an array of waveforms, but in your program you are only writing a single waveform.  You can either use the default read and index the array at 0 to return your waveform, or you can wire in a waveform constant to the data type input of the TDMS Read.

[ni_curious]

Thank you Devin for the response/help. 

Yesterday, I purchased some NI support for the year (just like it is a good idea to have a mechanic in the trunk when driving a Jaguar, it is also almost required to have NI support when working with LabVIEW if one expect to make any progress in a reasonable amount of time!) and I talked to NI support yesterday about this problem and although the apps engineer didn't have an immediated answer as to why this error is occuring, he was able to reproduce the problem and is working on an answer (which you have already given me).  He did, however, point me to a couple of NI_Scope "Streaming to Disk" VI examples on the NI website that, in the end, are more flexible and faster than the TDMS file approach and although it is far more complicated to implement than the Express VI, the performance improvement is worth it.  So I'll go that route and forgo the TDMS scene.

Roger

[Devin_K]

I'd just like to post an update on this issue.  This was reported to R&D (# 48TDDKXE) for further investigation.  The Write to Measurement File Express VI works fine in most situations, but there is an issue when waveforms with certain timestamps are used.  As mentioned above, a possible workaround is to use the other TDMS VIs in place of the Express VI if this error is encountered.  Thanks for the feedback, and for helping make LabVIEW and even better product!