The work environment of the future will be characterized by networked cooperating objects. Properties of cyber-physical systems (CPS) cover collection, storage, intelligent processing and communication of data. As a result, new possibilities regarding interaction and collaboration arise. This paper focuses on the technical and organizational challenges of a robust safety and protection system, which is suitable for a human-robot-collaboration scenario. Known requirements for both an integrated safety concept of human-robot-collaboration and the functional safety of machines and electronic systems are identified and a reference architecture is developed for a semi-automatic assembly process.