Modified Worst Case Response Time Analysis of CAN Bus Consisting of Nodes with Buffers
Wen Jin, Xi Chen, Hui Qun Zhang · Applied Mechanics and Materials · 2014
Worst case response time analysis of CAN Bus is the de facto method for evaluating the real-time performance which is a key feature of industrial bus. Compared with WCRT which aimed at nodes without buffer, a modified algorithm was presented to calculate the response time of CAN Bus consisting of nodes with both hardware and software buffers. The modified algorithm introduced local blocking time to describe the effect of buffers on response time. Based on the analysis of the different structures between hardware and software buffers, modified WCRT calculation methods of messages in hardware or software buffers were presented. Then the WCRT analysis of the whole system was obtained by consolidating the response time of node and bus. Results show that the response time calculated by the modified method is much longer than that calculated by the traditional WCRT. The modified method makes the WCRT analysis more coincident with the application of engineering, which helps the design and optimization of CAN based industrial bus.