TDMS 2.0 File Support for F# and C#

FSharp.Data.Tdms provides support for TDMS 2.0 files^[1] from F# and C# on .NET 6.0. From F# it allows you to access these in a type-safe manner through a generative https://docs.microsoft.com/en-us/dotnet/fsharp/tutorials/type-providers/[type provider], while plain old functions and methods are available to both F# and C#. FSharp.Data.Tdms reads raw channel data from TDMS 2.0 files as arrays.

Missing features

• Reading DAQmx raw data
• Defragmenting TDMS files
• Writing TDMS files

License

FSharp.Data.Tdms is licensed under an MIT License. Please refer to LICENSE for its full text.

Usage

From F#

Using the generative type provider, given a TDMS file Experiment.tdms with a channel containing floating-point values named Channel1 within a group named Group1:

#r "nuget: FSharp.Data.Tdms"

open FSharp.Data

[<Literal>]
let Path = "Experiment.tdms"

type Experiment = TdmsProvider<Path, WriteIndex = true>

let experiment = Experiment(Path)

experiment.Group1.Channel1.Data |> Array.iter (printfn "%f")

Alternatively, use the functions in the FSharp.Data.Tdms namespace, mainly those in the File module:

#r "nuget: FSharp.Data.Tdms"

open FSharp.Data.Tdms

File.read "Experiment.tdms" true
|> File.tryRawData<float> "Group1" "Channel1"
|> Option.defaultValue [||]
|> Array.iter (printfn "%f")

These functions have asynchronous equivalents:

#r "nuget: FSharp.Data.Tdms"

open FSharp.Control.Tasks.NonAffine
open FSharp.Data.Tdms

task {
let! file = File.readAsync "Experiment.tdms" true
let! data = File.tryRawDataAsync<float> "Group1" "Channel1"

    Option.defaultValue data
    |> Array.iter (printfn "%f")
}
|> Async.AwaitTask
|> Async.RunSynchronously

From C#

When using FSharp.Data.Tdms from C#, prefer the API for idiomatic C#:

using System;
using FSharp.Data.Tdms;

class Program
{
    static void Main(string[] args)
    {
        File.Read("Experiment.tdms", true).TryGetRawData("Group1", "Channel1", out double[] data);

        foreach (double sample in data)
        {
            Console.WriteLine(sample);
        }
    }
}

Or asynchronously:

using System;
using FSharp.Data.Tdms;

class Program
{
    static async Task Main(string[] args)
    {
        var file = await File.ReadAsync("Experiment.tdms", true);
        var data = await file.TryGetRawDataAsync("Group1", "Channel1");

        foreach (double sample in data)
        {
            Console.WriteLine(sample);
        }
    }
}

Property and raw data types

Most TDMS 2.0 data types directly map to .NET 5.0 data types. The first exception is tdsTypeTimeStamp, which you can read as either link:FSharp.Data.Tdms/Timestamp.fs[FSharp.Data.Tdms.Timestamp] (this data type corresponds to https://www.ni.com/nl-be/support/documentation/supplemental/08/labview-timestamp-overview.html[the NI LabVIEW timestamp]), System.DateTime, System.DateTimeOffset, or System.TimeSpan. In case of System.TimeSpan, FSharp.Data.Tdms returns the time elapsed since 01/01/1904 00:00:00.00 UTC, as per https://www.ni.com/nl-be/support/documentation/supplemental/08/labview-timestamp-overview.html[this support document from NI].

The second exception is tdsTypeExtendedFloat. Since .NET 5.0 does not support 80-bit extended precision floating point numbers, FSharp.Data.Tdms reads these as FSharp.Data.Tdms.Extended values.

Mapping from TDMS 2.0 to .NET 5.0 data types in FSharp.Data.Tdms

How to contribute

Imposter syndrome disclaimer: I want your help. No really, I do.

There might be a little voice inside that tells you you're not ready; that you need to do one more tutorial, or learn another framework, or write a few more blog posts before you can help me with this project.

I assure you, that's not the case.

And you don't just have to write code. You can help out by writing documentation, tests, or even by giving feedback about this work. (And yes, that includes giving feedback about the contribution guidelines.)

Thank you for contributing!

References