Patent ID: 7420985

Claim:
A method for operating an isochronous cyclical communication system, comprising: operating the communication system according to first project planning data for controlling isochronous realtime communication, wherein isochronous communications occurs during an isochronous realtime part of the communications cycle as set forth in the first project planning data and non-realtime communications occurs during a non-realtime part of the communications cycle; transmitting second project planning data during the non-realtime part of the communication cycle wherein isochronous communications occur during an isochronous realtime part of the communications cycle as set forth in the second project planning data and non-realtime communications occurs during a non-realtime part of the communications cycle; storing the second project planning data in a memory of a subscriber; transmitting a switchover point to the subscribers, the switchover point specifying a time at which a switchover from the first project planning data to the second project planning data is to occur; switching all subscribers at a same time from the first project planning data to the second project planning data when the switchover point occurs; assigning send and receive lists to a port for each of the subscribers, the first and the second project planning data containing the assignments; specifying data telegrams to be sent at a specific time in the send list; specifying data telegrams to be received at a specific time in the receive list; and storing in the memory of each of the subscribers a portion of the first and the second project planning data that contains the send and receive lists for the subscriber.