Tc2_DALI and Tc3_DALI in the same project

The Tc2_DALI library can be used for porting existing TwinCAT 2 projects to TwinCAT 3. At source code level, the TwinCAT 2 DALI library is compatible with the TwinCAT 3 Tc2_DALI library, which significantly simplifies the transfer of TwinCAT 2 projects to TwinCAT 3.

In contrast, the TwinCAT 3 library Tc3_DALI is a completely new development, which has been optimized for TwinCAT 3 and adapted to DALI-2. In this way it was possible to improve the performance and to simplify handling of the function blocks further.

	For new projects the Tc3_DALI library should therefore be used if possible.

This can lead to a situation where the Tc2_DALI library is used in a TwinCAT 3 project, this project is subsequently extended and the Tc3_DALI library is to be used for this purpose.

The following section illustrates how a KL6821 with the Tc2_DALI library and a further KL6821 with the Tc3_DALI library are operated in a TwinCAT 3 project.

The function blocks of the Tc2_DALI and Tc3_DALI libraries cannot be mixed on the same Bus Terminal. Each library must have exclusive access to a KL6821 or KL6811.

Add both libraries to the TwinCAT 3 project:

Tc2_DALI and Tc3_DALI in the same project 2:

The necessary variables must be created for each terminal and linked with the KL6821. In this example, the global variable list has the name GVL.

VAR_GLOBAL
    // Tc2_DALI
    stKL6821InDataTc2 AT %I* : Tc2_DALI.ST_KL6821InData;
    stKL6821OutDataTc2 AT %Q* : Tc2_DALI.ST_KL6821OutData;
    stCommandBufferKL6821 : Tc2_DALI.ST_DALIV2CommandBuffer;

    // Tc3_DALI
    stKL6821InDataTc3 AT %I* : Tc3_DALI.ST_KL6821InData;
    stKL6821OutDataTc3 AT %Q* : Tc3_DALI.ST_KL6821OutData;
END_VAR

Since the structures for linking the Bus Terminal have the same name in both libraries, the namespace must be prefixed. Although the structures have the same name in both libraries, they have different data types within the TwinCAT 3 type system. The namespace ensures that the appropriate data type from the respective library is used. For better readability, the namespace was also specified for the structure for the command buffer (ST_DALIV2CommandBuffer) from the Tc2_DALI library. Strictly speaking this would not be necessary at this point, because the identifier ST_DALIV2CommandBuffer only occurs in the Tc2_DALI library.

The namespace of a library is displayed in the Properties window.

Tc2_DALI and Tc3_DALI in the same project 3:

By convention, the namespace of the Beckhoff library is the same as the name of the library.

Next, the function block that is called by the communication task is created. In this function block, an instance of FB_KL6821Communication is called for each terminal, among other things. The namespace must also be specified here, since each library contains a function block with the name FB_KL6821Communication.

PROGRAM Communication
VAR
    // Tc2_DALI
    fbKL6821CommunicationTc2 : Tc2_DALI.FB_KL6821Communication;

    // Tc3_DALI
    fbKL6821CommunicationTc3 : Tc3_DALI.FB_KL6821Communication;
END_VAR

// Tc2_DALI
fbKL6821CommunicationTc2(stInData := GVL.stKL6821InDataTc2,
stOutData := GVL.stKL6821OutDataTc2,
stCommandBuffer := GVL.stCommandBufferKL6821);

// Tc3_DALI             
fbKL6821CommunicationTc3(stInData := GVL.stKL6821InDataTc3,
stOutData := GVL.stKL6821OutDataTc3);

When calling the respective function blocks for sending the DALI commands or for receiving the events, in most cases it is not necessary to specify the namespace. In the Tc2_DALI library all elements have the prefix DALIV2 while in the Tc3_DALI the prefix DALI is used.

Here you can download the sample project:Tc2_Tc3_DALI.zip