Calling a TcCOM object from the PLC

Creating a TcCOM wrapper FB

Set in the export configuration:

TcCom.TcComWrapperFb = 'true';

TcCom.TcComWrapperFbProperties = 'true'; % optional

Create instance of the TcCOM Wrapper function block

1. Create a PLC project.

2. Add the desired library under References.

Under Pous/TcCOM Wrapper you get a function block that you can instantiate in the PLC. In addition, necessary data types are created in the Duts folder.

Version 1: referencing a static module instance

The function block can be used to access module instances previously created in the XAE, e.g. under System > TcCOM Objects. For this static case, the object ID of the corresponding module instance must be transferred during declaration of the function block instance.

	The instance of the TcCOM object and the calling PLC must run in the same task. On the instance of the TcCOM object, make sure that under Parameter (Init) the entry ModuleCaller is set to Module and not to CyclicTask. In this case, the required memory for the TcCOM is obtained from the non paged pool of the system.

Declaration

// link wrapper with a static instance 
InitStrStatic      : ST_FB_TempCtrl_TcCOM_InitStruct := (noid := 16#01010010);   // OID from object1 in System > TcCOM Objects
fbTempCtrStatic    : FB_TempCtrl_TcCOM_InitStruct(InitStrStatic);
Inputs             : ST_TempCtrl_U_T;      // data type defined in TempCtrl library
Outputs            : ST_TempCtrl_Y_T;

Execution code

fbTempCtrStatic(stTempCtrl_U := Inputs, stTempCtrl_Y => Outputs);

Version 2: dynamic instantiation and referencing from the PLC

The function block can also be used in such a way that a TcCOM object is generated from the PLC and linked to the wrapper.

	The TaskOid of the PLC task must be used to specify the real-time task in which the wrapper is called. The ModuleCaller must also be set to Module here (via the Init structure). In this case, the required memory for the TcCOM is obtained from the router memory.

Declaration

// dynamic instance: create TcCOM from PLC
InitStrDyn          : ST_FB_TempCtrl_TcCOM_InitStruct := (
                        nTaskOid      := 16#02010030,             // take TaskOID of PlcTask
                        eModuleCaller   := E_ModuleCaller.Module );      // set module caller to "call by module"
fbTempCtrDyn        : FB_TempCtrl_TcCOM_InitStruct(InitStrDyn);
OutputsDyn          : ST_TempCtrl_Y_T;

Execution code

fbTempCtrDyn(stTempCtrl_U := Inputs, stTempCtrl_Y => OutputsDyn);

	The source code for the graph shown above is available in MATLAB^® via the Command Window `TwinCAT.ModuleGenerator.Samples.Start("TcCOM Wrapper Function Blocks")`