Method for failsafe operation of a network-enabled control system, wherein use is made of a control system which comprises - at least one controller, - at least one input assembly which is connected to the controller via a communication network and has at least one signal input, - at least one sensor (S, S1) which is connected to the input assembly and is connected to a first signal input of the input assembly, - at least one output assembly which is connected to the controller via the communication network and has at least one signal output, - wherein the input assembly is used to condition and/or convert the sensor signals for transmitting data to the controller via the communication network, - wherein the controller transmits diagnostic signals to the output assembly via the communication network, - wherein the diagnostic signals received by the output assembly via the communication network are transmitted back to the controller via the input assembly, characterized in that - use is made of an input assembly having two or more signal inputs, - the at least one signal output of the output assembly is connected to a second signal input of the input assembly, - the output assembly outputs the diagnostic signals received via the communication network in conditioned and/or converted form, as signals which correspond to sensor signals or are at least similar or identical to the latter, to the second signal input of the input assembly via the signal output, - the signals generated by the output assembly on the basis of the diagnostic signals and output to the input assembly are transmitted back from the input assembly to the controller again in conditioned and/or converted form via the communication network, - the controller detects errors inside the input assembly, the output assembly and/or the communication network by evaluating the transmitted diagnostic signals and the signals then transmitted back from the input assembly. - at least one controller, - at least one input assembly which is connected to the controller via a communication network and has at least one signal input, - at least one sensor (S, S1) which is connected to the input assembly and is connected to a first signal input of the input assembly, - at least one output assembly which is connected to the controller via the communication network and has at least one signal output, - wherein the input assembly is used to condition and/or convert the sensor signals for transmitting data to the controller via the communication network, - wherein the controller transmits diagnostic signals to the output assembly via the communication network, - wherein the diagnostic signals received by the output assembly via the communication network are transmitted back to the controller via the input assembly, characterized in that - use is made of an input assembly having two or more signal inputs, - the at least one signal output of the output assembly is connected to a second signal input of the input assembly, - the output assembly outputs the diagnostic signals received via the communication network in conditioned and/or converted form, as signals which correspond to sensor signals or are at least similar or identical to the latter, to the second signal input of the input assembly via the signal output, - the signals generated by the output assembly on the basis of the diagnostic signals and output to the input assembly are transmitted back from the input assembly to the controller again in conditioned and/or converted form via the communication network, - the controller detects errors inside the input assembly, the output assembly and/or the communication network by evaluating the transmitted diagnostic signals and the signals then transmitted back from the input assembly.