Interfaces

Several interfaces are available for the interaction of the modules developed by the user with the TwinCAT 3 system. These are described (at API level) in detail on these pages.

Name	Description
ITcUnknown	ITcUnknown defines the reference count as well as the querying of a reference to a more specific interface.
ITComObject	The ITComObject interface is implemented by every TwinCAT module.
ITcCyclic	The interface is implemented by TwinCAT modules that are called once per task cycle.
ITcCyclicCaller	Interface for logging the ItcCyclic interface of a module onto and off from a TwinCAT task.
ITcFileAccess	Interface for accessing the file system
ITcFileAccessAsync	Asynchronous access to file operations.
ITcPostCyclic	The interface is implemented by TwinCAT modules that are called once per task cycle following the output update.
ITcPostCyclicCaller	Interface for logging the ITcPostCyclic interface of a module onto and off from a TwinCAT task.
ITcIoCyclic	This interface is implemented by TwinCAT modules that are called during the input update and output update within a task cycle.
ITcIoCyclicCaller	Interface for logging the ITcIoCyclic interface of a module onto and off from a TwinCAT task.
ITcRTimeTask	Query of extended TwinCAT task information.
ITcTask	Query of the timestamp and task-specific information of a TwinCAT task.
ITcTaskNotification	Executes a callback if the cycle time was exceeded during the previous cycle.

TwinCAT SDK

TwinCAT SDK contains a number of functions, which can be found in C:\TwinCAT\3.1\sdk\Include.

The TcCOM framework is provided here (in particular TcInterfaces.h and TcServices.h).
Tasks and data area access is provided via TcIoInterfaces.h.
SDK functions are the mathematical functions.
Subset of STL.
TwinCAT runtime RtlR0.h
Methods for ADS communication
Classes / functions with names beginning with "Os" must not be used in a real-time context.

Further Information