NI TDM/TDMS is a structured, high-speed binary file format optimized for saving and exchanging measurement data. TDM supports fast searching without a custom database.

To reduce the need to design and maintain your own file format for measurement data, NI defines the flexible technical data management (TDM) data model. The TDM model is accessible through LabVIEW, LabWindows™/CVI™, Measurement Studio, SignalExpress, and DIAdem. The TDM data model also enables you to write well-organized data regardless of which third-party products you are using.

The TDM data model includes metadata support.

  • The TDM data model structures metadata into groups and channels.
  • You can add user-defined properties to files, groups, and channels.

You can identify whether an element in a file is a group, a channel, or a property.

The TDM data model supports the following two file formats:

  • TDM—(Windows only) The TDM file format saves the raw data that the measurement hardware acquires and the metadata in separate files. Metadata can be the name and unit of a measurement channel, the name of the test engineer, and other information. The metadata is in the XML format with the .tdm extension. The raw data is in a compact binary format with the .tdx extension.
  • TDM Streaming—TDMS—The TDMS file format saves both the raw data and the metadata in the binary format in one file with the .tdms extension.
    Note When creating or opening a .tdms file, LabVIEW might automatically create a .tdms_index file. LabVIEW uses the .tdms_index file to speed up random access to the .tdms file. The .tdms_index file is optional in TDMS applications. If you have disk space limitations, configure the TDMS Open function to stop generating this file.