How to link Beckhoff TwinCAT 3 to a Visual Studio HMI created in C#?

Question

I am quite new in TwinCAT 3 and .NET framework. I am trying just to create an HMI with a button and link it to a variable in TwinCAT 3. I am controlling by TwinCAT 3 a Beckhoff output card (EL2014) so I have created the following variable named "Out_1" and linked it to one card output:

Variable properties:

The code of the button is:

private void button1_Click(object sender, EventArgs e)
{
    TwinCAT.Ads.TcAdsClient tcAds = new TwinCAT.Ads.TcAdsClient();
    tcAds.Connect(301);

    tcAds.WriteSymbol("TIRT.Task 2.Outputs.Out1", true, 
        reloadSymbolInfo: true);
}

The following message is appearing:

Additional information: Ads-Error 0x710 : Symbol could not be found.

The symbol name used to access de variable is not correct and I don't really know how may I write it.

Does anyone know how can I access this variable?

Thank you very much.

Answer 1

If you leave out the "TIRT" it will work, eg "Task 2.Outputs.Out1".

Be sure that "Create Symbols" is checked when you double click on the task: