
https://profinetuniversity.com/wp-content/uploads/2018/04/PROFINET-OSI-Layer-Stack.png
https://profinetuniversity.com/wp-content/uploads/2018/04/PROFINET-NRT-Packet-Payload-1024x126.png
https://profinetuniversity.com/wp-content/uploads/2018/04/PROFINET-RT-Packet-Payload-1-1024x126.png
https://profinetuniversity.com/wp-content/uploads/2018/04/PROFINET-OSI-Layer-Stack-1.png
PROFINET uses the NRT channel for less time-sensitive communications, like setting up a connection between a device and controller or accessing diagnostic data from an external network. But that added flexibility comes with increased data overhead – 108 extra bytes on each packet.