System and method for transmitting real-time-critical and non-real-time-critical data in a distributed industrial automation system

A method of communicating in a distributed, industrial automation system, comprising:

• providing a plurality of user devices and a plurality of Ethernet switching units, wherein an Ethernet switching unit is integrated in each user device;
• operating the plurality of Ethernet switching units via a common synchronous time base,
• wherein a communication between the plurality of user devices and Ethernet switching units is effected in transmission cycles,
• wherein each transmission cycle is subdivided into a first section for transmitting real-time-critical data and a second section for transmitting non-real-time-critical data, and
• wherein, for each transmission cycle, a length of the second section for transmitting non-real-time-critical data is automatically established by a length of the first section for transmitting real-time-critical data;
• receiving at an Ethernet switching unit real-time-critical data for a user device of the distributed, industrial automation system;
• transmitting the real-time-critical data to the user device during the first section of the transmission cycle intended for transmission of real-time-critical data;
• receiving at the Ethernet switching unit non-real-time-critical data during the transmission of the real-time-critical data;
• storing the non-real-time critical data in a memory of the user device or the Ethernet switching unit;
• transmitting the non-real-time critical data to a receiver during the second section of the transmission cycle intended for transmission of non-real-time critical data.