COM

COM - Microsoft Interface stands for Component Object Model, a specification for developing modular software components which can be used by each COM compatible application. COM components can be easily integrated in such applications and can even be removed from an application at run time. COM components can be programmed in various different programming languages although C++ is used mostly. The specifications OLE, ActiveX and DirectX are based on the COM technology.

Via COM, the objects of applications are open for development programs, macro languages, and other applications that support automation. Via a spreadsheet program, for example, a table, a chart, a cell, or a cell space may be open, whereas all objects have a different object type. A word processor may open its objects such as an application, a document, a paragraph, a bookmark, or a choice.

If an application supports COM, you can access the open objects and change them by calling methods for this object or by calling the properties of the object and defining them.

See also https://en.wikipedia.org/wiki/Component_Object_Model for more information.

COM in WinCC OA

In WinCC OA, COM can be used in CTRL and as a COM Manager.

COM in Control (createComObject, releaseComObject)

Control uses the COM interface and the COM functions createComObject() and releaseComObject() can be used in Control.

COM Manager

The COM manager (wincc_oa_path/bin/WCCOAcom.dll) is used as a means of communication between COM clients, e.g. Excel and WinCC OA . The COM Manager is used for Excel and VBA in ExcelReport.

The COM Manager contains four COM objects, which are responsible for different tasks.
  • The ComManager object encapsulates a complete WinCC OA manager and enables access to the data points of WinCC OA whereas the functions are similar to the CTRL functions.
  • The ReportExt object is an extension of the ComManager object that was implemented specifically for the Excel report. The Excel report and the ReportExt object are not described in detail here.
  • The ProjAdmin and ProjAdminAuto objects can be used to access information about installed WinCC OA projects. The ProjAdminAuto object can also be used in script languages like vbScript.

For the description of the COM objects, see the chapters ComManager Object, ProjAdmin-Object and ProjAdminAuto Object.