To achieve an automatic adjustment of a monitoring time in an automation system with a first automation device and a second automation device, at least one of the two automation devices operates a measuring program. A desired ring interruption is carried out by the measuring program by blocking a ring port in order thus to provoke a ring reconfiguration that utilizes a reconfiguration time. The blockage of the ring port is canceled again after the reconfiguration time has elapsed. The ring port is blocked again if the ring port has been opened by the ring reconfiguration, and all routing tables are deleted. As a result of this, at least the peripheral units are triggered to learn new network routes. Runtimes of test telegrams are measured, and a maximum value of the measured runtimes is stored. The measured maximum value is used for a dynamic adjustment of the monitoring time.