Method for data communication between subscribers in an automation network, master subscriber for an automation network, and automation network

A method for real-time capable data communication between subscribers in an automation network, wherein the automation network comprises:

• an active subscriber, a plurality of passive subscribers and at least one connecting unit, which are connected to one another via a data line network,
• the data line network being configured as a field-bus system,
• the active subscriber being configured to send out data packets to the passive subscribers for the purpose of data communication in circulation in which the data packets are transmitted from the active subscriber to the passive subscribers and data packets are transmitted from the passive subscribers to the active subscriber, and
• the connecting unit being configured to forward data packets addressed to the passive subscribers and to return the data packets to the active subscriber;
• the method comprising the method steps:
• the active subscriber arranging n data packets to be transmitted in a transmission order with a total occupancy time duration of the transmission order in a first arranging step, wherein the total occupancy time duration comprises a period from transmission by the active subscriber of a first bit of a first transmitted data packet to receipt by the active subscriber of a last bit of a last received data packet,
• the active subscriber performing an optimizing procedure for determining an optimized transmission order with minimum total occupancy time duration in an optimizing step, the optimizing procedure comprising a finite number of at most n*(n−1)/2 pairwise permutations of orders of n data packets consecutive in the transmission order and determining of the total occupancy time durations of the transmission orders generated by the permutations, and
• the active subscriber transmitting the n data packets in the optimized transmission order to the passive subscribers in a transmitting step.