Hardware Level
In TwinCAT 3, the common I/O system is used to administrate both purely functional and safety hardware. This means, that there is no differentiation between purely functional components and safety components. The safety terminals are handled like any other field bus participant. All field bus information on this level can be accessed here (for example CoE-Online data). All safety-relevant data (including the safety parameters of the safety hardware) is stored in the upper two levels of the basic structure). The placement of the I/O level and example CoE-Online data is shown in the following Figure.
The advantage of the already introduced 3-level design is the fact, that no safety-relevant properties have to be configured or stored on the hardware level.