Abstract: A circuit arrangement allows data, which are necessary for building up fault-tolerant structures, to be transmitted on standard ring-shaped bus systems. Its implementation requires a monitoring unit and input and output units which transmit or receive data for control. The circuit arrangement handles the task of detecting any faults which can become a danger for the process within a machine or plant. Due to its internal configuration, the circuit arrangement identifies any fault even before the detection of the fault and initiates a protected switch-off. In this arrangement, it is of no importance whether it is the external control unit or the bus system used which is responsible for the fault.