How it works
PROFINET employs different protocols and services for the various performance classes. The real-time type PROFINET RT sends payload and non-time-critical data within one cycle, following the producer/consumer principle. An RT channel is reserved for high-priority payload which is transmitted directly via the Ethernet protocol. In contrast, diagnosis and configuration data are sent via UDP/IP. Thus, cycle times of about 10 ms can be realized for I/O applications. Employing time-division multiplexing based on managed switches, PROFINET IRT provides clock-synchronized cycle times below one millisecond, which are required in applications such as motion control. Furthermore, PROFINET IRT uses a particular frame format, Profinet Real Time Telegram, which requires specific ASICs on the interface side.