These expansion modules typically connect to the base unit via a dedicated interface, allowing for easy scaling of safety functions. http://www.pilz.com They are used to extend the number of safety contacts or inputs/outputs beyond what the base unit alone can accommodate. Safety solutions provider since 2011, We offer Pilz.
Each module will usually have its own specifications and configuration options, and they must be compatible with the base unit in terms of communication protocols and safety ratings. For exact details on compatibility and configuration, it would be best to refer to the specific documentation provided by Pilz for the PNOZ X series and the expansion modules you’re using.