Basic principles
The TwinCAT 3 Interface for Inventor® connects TwinCAT with Autodesk® Inventor®. The goal of this coupling is "software-in-the-loop simulation" (SiL simulation, abbreviated as SiL in the following). In virtual commissioning or in an SiL, a closed loop is essential. I.e. values are written from the controller to the CAD model (axis positions) and at the same time values are fed back from the model to the controller/PLC (sensor values). In this context, the visualization or simulation helps the programmer to better understand the behavior of the controller and to detect possible problems in this loop.
The TwinCAT 3 Interface for Inventor® uses the design data from Autodesk® Inventor® and the position values and other values from a TwinCAT project for the SiL. The axes to be moved, which must be configured in Autodesk® Inventor®, are imported into this TwinCAT project. The CAD software parameters are linked to the TwinCAT symbols for the simulation of motion.
The 3D simulation is not real-time capable because Autodesk® Inventor® runs on standard Windows systems or does not have a real-time simulation environment.
Operating principle
To create a simulation with the TwinCAT 3 Interface for Inventor®, a 3D model and a PLC project are basically required. During the design of a 3D model in Autodesk® Inventor®, the assemblies and axes that should be mobile later on must be configured accordingly. In addition, a PLC project is required in TwinCAT to control the machine's movement. In the TwinCAT 3 Interface for Inventor®, the mobile simulation axes of the 3D model are connected to the PLC. When running the simulation, the values are copied from the controller to the model as axis positions and values are simultaneously fed back from the model to the controller as sensor values. The movement that occurs due to the commands from the controller is displayed in the 3D model.
To use the TwinCAT 3 Interface for Inventor®, TwinCAT is triggered by an external CAD program, i.e. Autodesk® Inventor®. The TwinCAT 3 Usermode Runtime enables synchronous integration of the execution. TwinCAT 3 offers an interface for this, whereby the ticks for the runtime are specified externally. The CAD-specific add-in is used to initialize and start the TwinCAT Usermode Runtime in Autodesk® Inventor®. After initializing the Usermode Runtime, the target can be selected in TwinCAT. After starting the runtime, values can be exchanged between Autodesk® Inventor® and TwinCAT. The Usermode Runtime used for coupling the TwinCAT project and Autodesk® Inventor® has the task of ensuring synchronous execution of the non-real-time capable Autodesk® Inventor® and the real-time capable PLC code.