Bus system for a process system, having a first bus subscriber which transmits bus messages and having at least one first bus subscriber which receives bus messages, wherein the transmitting first bus subscriber and the receiving first bus subscriber are connected to one another via a first data bus, wherein the transmitting first bus subscriber is designed such that it transmits control commands to the receiving first bus subscriber, wherein the receiving first bus subscriber is designed such that it executes the control commands of the transmitting first bus subscriber, wherein the bus system also has the features that a transmitting second bus subscriber and at least one receiving second bus subscriber are provided, that the transmitting second bus subscriber and the receiving second bus subscriber are connected to one another via a second data bus, that the transmitting second bus subscriber is designed such that it transmits control commands to the receiving second bus subscriber, that the receiving second bus subscriber is designed such that it executes the control commands of the transmitting second bus subscriber, that the transmitting first bus subscriber and the transmitting second bus subscriber are connected to one another via a monitoring communication channel and are designed such that they functionally monitor one another, that the first data bus and the second data bus can be connected to one another and disconnected from one another via a switching device which can be controlled by at least one circuit unit, wherein the first data bus and the second data bus are disconnected from one another in the simultaneous go state of the transmitting first bus subscriber and of the transmitting second bus subscriber, that the circuit unit is designed such that, in the fault state of the transmitting first bus subscriber or in the fault state of the transmitting second bus subscriber, it connects the first data bus and the second data bus to each other via the switching device so that the functional transmitting first bus subscriber is connected to the receiving first bus subscriber and the receiving second bus subscriber, or the functional transmitting second bus subscriber is connected to the receiving first bus subscriber and the receiving second bus subscriber, and that the functional transmitting first bus subscriber and the functional transmitting second bus subscriber are designed such that, in the fault state of the respective other transmitting bus subscriber (5, 2), they transmit control commands both to the receiving first bus subscriber and to the receiving second bus subscriber. wherein the bus system also has the features that a transmitting second bus subscriber and at least one receiving second bus subscriber are provided, that the transmitting second bus subscriber and the receiving second bus subscriber are connected to one another via a second data bus, that the transmitting second bus subscriber is designed such that it transmits control commands to the receiving second bus subscriber, that the receiving second bus subscriber is designed such that it executes the control commands of the transmitting second bus subscriber, that the transmitting first bus subscriber and the transmitting second bus subscriber are connected to one another via a monitoring communication channel and are designed such that they functionally monitor one another, that the first data bus and the second data bus can be connected to one another and disconnected from one another via a switching device which can be controlled by at least one circuit unit, wherein the first data bus and the second data bus are disconnected from one another in the simultaneous go state of the transmitting first bus subscriber and of the transmitting second bus subscriber, that the circuit unit is designed such that, in the fault state of the transmitting first bus subscriber or in the fault state of the transmitting second bus subscriber, it connects the first data bus and the second data bus to each other via the switching device so that the functional transmitting first bus subscriber is connected to the receiving first bus subscriber and the receiving second bus subscriber, or the functional transmitting second bus subscriber is connected to the receiving first bus subscriber and the receiving second bus subscriber, and that the functional transmitting first bus subscriber and the functional transmitting second bus subscriber are designed such that, in the fault state of the respective other transmitting bus subscriber (5, 2), they transmit control commands both to the receiving first bus subscriber and to the receiving second bus subscriber.