Method for Operating an Industrial Automation System Communication Network Comprising a Plurality of Communication Devices, and Control Unit

A method for operating an industrial automation system communication network comprising a plurality of communication devices, a plurality of control units each controlling functions of a plurality of associated communication devices, and a predefinable share of system resources of an associated communication device being made available for each control unit for a predefinable resource usage duration, the method comprising:

• determining, by each of the plurality of control units, during the resource usage duration, communication network paths between selected communication devices via associated communication devices based on a quality measure taking into account respective available system resources and control routing or switching functions of associated communication devices in accordance with the determined communication network paths;
• capturing synchronously, by the plurality of control units, state variables of the communication devices when predefinable synchronization events occur and comparing said state variables with one another, the synchronization events comprising predefinable synchronization intervals and the resource usage duration is limited by successive synchronization events;
• determining, by the plurality of control units, for at least one past resource usage duration, which quality measure changes result for communication network paths to be determined based on a determination time available for path determination and determining a first correction value for the synchronization events based on the quality measure changes;
• determining, by the plurality of control units, inconsistent state variables when comparing the state variables with one another and determining a second correction value for the synchronization events based on inconsistent state variables;
• and
• specifying changed synchronization events for the control units based on the first and second correction values.

A control unit comprising:

• a processor;
• and
• memory;
• wherein the control unit is configured to:
• control functions of a plurality of associated communication devices, a predefinable share of system resources of an associated communication device being available for the control unit for a predefinable resource usage duration,
• determine, during the resource usage duration, communication network paths between selected communication devices via associated communication devices based on a quality measure taking into account respective available system resources and control at least one of (i) routing and (ii) switching functions of the associated communication devices in accordance with the determined communication network paths,
• capture state variables of the communication devices in sync with other control units when predefinable synchronization events occur and compare said state variables with one another, the synchronization events comprising predefinable synchronization intervals and the resource usage duration being limited by successive synchronization events,
• determine, for at least one past resource usage duration, which quality measure changes result for communication network paths to be determined based on a determination time available for path determination and determine a first correction value for the synchronization events based on the quality measure changes,
• determine inconsistent state variables when comparing the state variables and determine a second correction value for the synchronization events based on inconsistent state variables, and
• specify changed synchronization events based on the first and second correction values.