Precision of the Write to Measurement File Express VI

Updated Nov 29, 2023

Reported In

Software

  • LabVIEW Full
  • LabVIEW Report Generation Toolkit

Issue Details

I'm saving my data using the Write to Measurement File Express VI. When saving data with high precision, the data gets truncated and some of the precision is lost. Why is this, and can I recover the lost precision?

Solution

While express VIs are convenient for many applications, they lack the robust features that LabVIEW primitives offer. LabVIEW Measurement Files are purposely designed to store data with a maximum precision of six digits. Any data that is truncated will be irrecoverable. 
 

Additional Information

This standard was decided upon for multiple reasons. Some of the reasons include:
  • The limited digits of precision reduces disk space usage for large data files.
  • The prefixed length of data reduces complexity and eliminates the Express User from having to worry about formatting.
  • It is actually a text file and is designed to be easily parsed and read when imported into a spreadsheet program (i.e., Microsoft Excel) or a text editor (i.e., Notepad).

Within the LabVIEW shipping examples, there are many functional VIs already created that you can work off of using LabVIEW File I/O primitives. This is the recommended way to develop these kind of applications and will allow for more robust programs. You can examples at:

LabVIEW >> Help >> Find Examples >> Fundamentals >> File input and Output >> Spreadsheet >> Tab-Delimited Data.lvproj OR Write to Spreadsheet (both are in the same directory)
 

Related Links

File I/O VIs and Functions

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