TDM/TDMS Files

To reduce the need to design and maintain your own file format for measurement data, National Instruments defines the flexible technical data management (TDM) data model, which 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 supports the following two file formats:

• (Windows) TDM—The TDM file format saves the raw data that the measurement hardware acquires and the meta data in separate files. Meta data can be the name and unit of a measurement channel, the name of the test engineer, and other information. The meta data 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 meta data 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.

The TDM data model structures the meta data into groups and channels, and adds user-defined properties. You can identify whether an element in a file is a group, a channel, or a property.

Related Information

TDM Data Model

TDM versus TDMS

Integrating TDMS in Third-Party Products