A control and data transmission installation and a process for transmission of safely-related data in a control and data transmission installation. In accordance with the invention, safety procedures of existing field bus systems, particularly the interbus, are improved in such a way that there is no need either for additional lines for the transmission of control signals or redundant, safety-related units. In the inventive control and data installation, a master control device and a number of bus subscribers each include respective safety-related devices for carrying out predetermined safety functions. The safety-related devices can communicate with each other by way of a field bus.
