What’s the Deal with TDMS Files? A guide for the uninitiated

Have you ever come across a TDMS file and wondered what it is? Well so have I. Here is what I’ve learned (so far):

TDMS (Technical Data Management Streaming) files are special containers created by National Instruments to store measurement data. Think of them as specialized filing cabinets for technical information that work better than basic formats like Excel or CSVs when dealing with lots of measurements. This is because they can be read little by little, if you don’t want to work with the whole file at once, and a feature I personally like: The ability to store metadata along with the data in a nice and simple way. But before diving too deep with that, let’s start with the basics:

How They’re Organized

TDMS files are built on a three-level system:

• The file itself (the main container)
• Groups inside the file (Group similar things in here)
• Channels within each group (where the actual data lives)

Why we Love Them

These files are popular in many technical fields because they:

• Store data efficiently (they’re compact and quick to read/write)
• Can handle continuous data recording (great for sensors that keep measuring)
• Allow you to attach important notes/metadata to your data
• Support different types of information in one file (numbers, text, timestamps)

The Cool Part: Metadata

Before I mentioned the metadata and it’s really one of the best features of this file format and a good reason to consider it - essentially you can keep notes about your data, in the actual data file. This means you can include units, timestamps, or any contextual information right alongside your measurements. No more wondering “what was this measurement about again?” months later!

Working with TDMS Files

There are some simple libraries to work with these files:

• If you’re using Python, the npTDMS library makes it straightforward:

import nptdms
from nptdms import TdmsFile

# Open the (whole) file and read it into memory
my_file = TdmsFile.read("sensor_data.tdms")

# Get a specific group and channel
temperature_group = my_file["Temperature_Data"]
sensor_1 = temperature_group["Kitchen_Sensor"]

# Get the actual readings
readings = sensor_1[:]

# Check the metadata
units = sensor_1.properties.get("units")
print(f"Temperature is measured in {units}")

See https://nptdms.readthedocs.io/en/stable/index.html for more detailed examples and documentation

When You Might Encounter Them

You’ll typically run into TDMS files when working with:

• Lab equipment and test systems
• Data loggers and sensors
• Industrial monitoring setups
• Engineering test benches
• Embedded data collection systems

The Tradeoffs

While TDMS files are great for technical work, they’re not perfect for everything:

• They’re specialized (not as universal as CSV files or Excel, so don’t expect everyone to know what to do with them)
• You need specific tools to open them
• They’re mostly just used in engineering/physics

The Bottom Line

TDMS files shine when you need to capture lots of measurements efficiently while keeping track of what all that data means. They’re especially valuable when working with sensors, data acquisition systems, or any situation where you’re collecting data at high speeds or for long periods.

If you’re working with electronic systems, embedded software, or any kind of technical measurements, knowing how to use TDMS files can make your life a whole lot easier!