Technical Data Management Streaming (TDMS) is a binary file format that allows for high-speed data logging. When you enable TDMS data logging, NI-DAQmx can stream data directly from the device buffer to the hard disk. NI-DAQmx improves performance and reduces the disk footprint by writing raw data to the TDMS file, including the scaling information separately for use when reading back the TDMS file. You can also read data while logging to disk.

For optimal performance, follow these tips:

  • Use a PCI Express or PXI Express device with a RAID array.
  • Log data only. For very high-speed acquisitions, logging and reading data can slow performance.
  • If logging and reading data, ensure the number of samples per channel to read is evenly divisible by the sector size of the hard disk.
  • If manually configuring the buffer size, choose a multiple of eight times the sector size of the hard disk. For instance, if your sector size is 512 bytes, your buffer size might be 4,096 samples.

NI provides a number of mechanisms for reading TDMS files, including software support in LabVIEW, LabWindows/CVI, ANSI C, DIAdem, and Measurement Studio. In addition, NI provides a Microsoft Excel plug in. Refer to ni.com/tdms for additional information. For information about high-speed data streaming, refer to ni.com/streaming.