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Unable to View LabVIEW SignalExpress TDMS Files in LabVIEW



Primary Software:
Primary Software Version: 1.0
Primary Software Fixed Version: N/A
Secondary Software: LabVIEW Development Systems>>LabVIEW Full Development System, LabVIEW Development Systems>>LabVIEW Base Package, LabVIEW Development Systems>>LabVIEW Professional Development System

Problem:
When I create a log file in LabVIEW SignalExpress the data is stored in a Technical Data Management Streaming (TDMS) file.  



If I try to view the SignalExpress TDMS file in LabVIEW with the Read From Measurement File.vi it looks nothing like the signal that was recorded in SignalExpress.


Why is this occurring and how can I view the data in LabVIEW?


Solution:
The data stored in a LabVIEW SignalExpress TDMS log file includes decimated data used for efficient LabVIEW SignalExpress internal viewing of the data. As such you can discard this decimated data when using the TDMS data in LabVIEW.

You can either use the Read From Measurement File Express VI or the TDMS VIs available in the Programming»File I/O»TDM Streaming palette.

Using the Read From Measurement File
Complete the following steps to use the Read From Measurement File VI to correctly open a TDMS file generated by LabVIEW SignalExpress:
  1. Drop the Read From Measurement File VI on to the block diagram
  2. Select the Binary (TDMS) File Format in the Configure Read From Measurement File dialog box


  3. Convert the dynamic data output of the Read From Measurement File VI to an array of waveforms using a Convert From Dynamic Data Type VI


  4. In the Convert From Dynamic Data Type configuration dialog box select 1D array of waveform as the Resulting data type


  5. The outputted array of waveforms are now only the full data from the TDMS file
Using the TDMS API VIs
If you need more control over how the TDMS file is opened and parsed you can use the TDMS VIs available in LabVIEW. However, when the LabVIEW SignalExpress TDMS file is read into LabVIEW the decimated and total data groups will be returned. Therefore, as shown in the screenshot below the only group that is valid data is the one ending in  - All Data.



Note: When you create your log file in LabVIEW SignalExpress, if you intend for it only to be viewed in LabVIEW, you can disable LabVIEW SignalExpress's option to calculate all of the decimated data reducing the size of your file. To disable the decimation feature select Never in the Prepare log data for viewing field. Refer to LabVIEW SignalExpress Help: Logging Page (Options Dialog Box) for more details.

Related Links:
KnowledgeBase 4FIBL6SK: Unable to Import TDMS Files Created in LabVIEW into LabVIEW SignalExpress
LabVIEW SignalExpress Help: Logging Page (Options Dialog Box)
Developer Zone Tutorial: Introduction to LabVIEW TDM Streaming VIs

Attachments:

 






Report Date: 06/07/2007
Last Updated: 08/28/2013
Document ID: 4A68RJ9S

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