Yang Minqiang, Li Xuyuan, Zhou Qingguo, Nicholas Mc Guire
Lanzhou University, Lanzhou, P. R. China

In despite of various attempts to put field-bus on Ethernet, and Ethernet field-buses attracted more and more attention, the industrial deciders are still hesitating about the choice between the Ethernet variant. For the good features and performance of RT-PREEMPT, a soft PLC which consists of openPOWERLINK and RT-PREEMPT might be a cheap and easy solution for many deployed cases. In this paper, we would evaluate synchronism, jitter, cycle time and other most relevant indicators of openPOWERLINK over RT-PREEMPT. Distributed systems are used commonly to implement tightly coordinated controllers, data acquisition or synchronization. To allow evaluating such typical scenarios with inexpensive hardware we use the paraport to simulate the input/output of a PLC. This simple setup allows us to evaluate the capabilities of the overall setup including the hardware, OS and protocol stack - thus allowing to judge the capabilities of the setup for practical purposes and provide reference to the industrial people.