Method for operating an isochronous cyclic communication system

The invention relates to a method for operating an isochronous, cyclic communication system, wherein one communication cycle can be subdivided into a first part for real-time communication and a second part for non-real-time communication. The communication system comprises subscribers and a memory is provided to store configuration data in each subscriber. The inventive method comprises the following steps: the communication system is operated with first configuration data for real-time communication; second configuration data is transmitted for real-time communication in a second part of one or several communication cycles; the second configuration data is stored in the memories of the subscribers; a transfer time indicating the moment in time when transfer occurs from the first configuration data to the second configuration data.