Method calls

The TwinCAT OPC UA I/O Client supports the calling of server methods. You can add a method to the process image like any other variable. The "input arguments" of the method are then available as output variables in the process image, whereas the "output arguments" are added as input variables. Additional input and output variables, e.g. bExecute, bBusy, bError, are added to the process image so that the method can be called.

Example: Method on server

Example: Method after addition to the process image

You can then create a mapping between the input/output variables and the PLC variables.

Calling of a method

To call a method, set the output variable bExecute to TRUE. You can check whether the method call has been completed and whether it was successful via the input variables nErrorID, bDone, bBusy and bError.