Why TDMS File Size Stays Same for Different Input Data Types

Updated May 6, 2026

Reported In

Software

  • LabVIEW

Issue Details

I want to minimize the TDMS file size generated by Write To Measurement File function. However I notice no matter I input single-precision floating point or double-precision floating point to it, the file size of the TDMS generated will still be the same as double numeric, why?

Solution

This is because the input data type for Write To Measurement File function is dynamic data type. Dynamic data for single scalar floating point input will always using double-precision.

If you input the data to this function without conversion, the data will still convert to dynamic data and you will see a coercion dot as shown below:

Additional Information

If you are using TDM Streaming functions to save your data to TDMS file, it is possible to follow the data type of your input and minimize the file size.

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