Evaluation of timing characteristics of a prototype system based on PROFINET IO RT_Class 3

The PROFINET architecture can provide real-time, high-performance, isochronous communication regardless the presence of other real-time data exchange and TCP/IP traffic for a considerable portion of network bandwidth. In this work some experimental tests have been executed in order to evaluate timing performance of a PROFINET ASIC (ERTEC 400 chip) and its related development kits. Results shows that communication isochrony has been ensured with a jitter of about 100 ns despite TCP traffic (70% of bandwidth) and presence of PROFINET IO RTjClass 1 nodes. On the contrary, some improvements are still needed as regard features of the software stack and of the interface with the application layerl. The highlighted problems will be probably fixed in the next firmware releases planned by manufacturer.