Real-time Performance Analysis of Industrial Embedded Control Systems Using Switched Ethernet

The appearance of the switched Ethernet opens up the use of Ethernet as a reliable deterministic communication technology. Comparing with traditional Ethernet, the real-time characteristic of the switched Ethernet is more advanced because it provides a private collision domain to each port of a switch to avoid collisions. Based on the two embedded ARM controllers connected over the switched Ethernet, the real-time performance of four different protocols on ARM-Linux 2.4 and 2.6 platforms are assessed and discussed in this paper. The testing results show that the controllers connected over the switched Ethernet, with which using ARM-Linux and UDP or RTP protocol, to some extent has potential to be used in many real-time control applications, though some drawbacks still need to be improved. The other interesting point seen from the results is that there is a visible difference in real-time performance between ARM-Linux 2.4 and 2.6. This difference is ARM-Linux 2.6 has higher real-time performance than ARM-Linux 2.4. So ARM-Linux 2.6 in many networked control applications may be a better choice in many cases.