A TDM file is a file format developed by NI (National Instruments) specifically designed for storing measurement data.
Understanding the TDM File Format
At its core, the TDM file format is the NI file format for saving measurement data. It serves as a standardized way to store information acquired during tests, experiments, or monitoring processes using NI hardware and software.
One of the key features highlighted in the reference is how the TDM format manages different types of data:
- Bulk Data: This includes the raw signals and measurements acquired by the hardware. Think of this as the actual numbers representing voltage, temperature, pressure, etc., over time.
- Descriptive Data (Metadata): This data describes what the bulk data represents and how it was acquired. This includes crucial context that makes the raw numbers meaningful.
Importantly, the TDM file format saves the signals acquired by the measurement hardware, the bulk data, and the descriptive data, the metadata, in separate files. This separation helps in managing and organizing large sets of measurement data effectively.
Components of TDM
The TDM format typically involves at least two files:
- The TDM File (.tdm): This file contains the metadata, providing structure and context for the raw data.
- The TDM Data File (.tdx): This file contains the actual bulk measurement data (the signals).
Examples of Metadata
As per the reference, the metadata saved in the TDM file can include details such as:
- The name and unit of a measurement channel (e.g., "Voltage", "Volts" or "Temperature", "°C").
- The name of the test engineer.
- Information about the test setup.
- Timestamp of the measurement.
- Acquisition settings.
This metadata is vital for understanding, analyzing, and searching through large volumes of acquired data. It provides the "story" behind the numbers.
Why Use TDM?
Using a dedicated format like TDM offers several advantages for measurement data:
- Organization: Separating data and metadata provides a clear structure.
- Searchability: Rich metadata makes it easier to search and filter data based on specific criteria.
- Scalability: Designed to handle large datasets efficiently.
- Integration: Works seamlessly with NI software like DIAdem for analysis and reporting.
In summary, a TDM file isn't just a single file; it's part of a pair (TDM and TDX) that together provide a structured, organized, and well-documented way to save measurement data, keeping the raw signals separate from their descriptive context.
