Response time for IEC 61499 over Ethernet

Abstract

Abstract-The IEC 61499 standard provides means to specify distributed control systems in terms of function blocks. The execution model is event driven (asynchronous), where triggering events may be associated with data (and seen as a message). In this paper we propose a low complexity implementation technique allowing to assess end-to-end response time of event chains spanning over a set of networked devices. In this paper we develop a method to provide safe end-to-end response time taking both intra-and inter-device delivery delays into account. As a use case we study the implementation onto (single-core) ARMcortex based devices communicating over a switched Ethernet network. For the analysis we define a generic switch model and an experimental setup allowing us to study the impact of network topology as well as 802.1Q quality of service in a mixed critical setting. Our results indicate that safe sub millisecond end-to-end response times can be obtained using the proposed approach.

Study on real-time industrial control networks

“…As suggested by Seno et al in [68], IEC 61784-2 [69] defines performance indicators (i.e., QoS parameters), such as throughput, bandwidth, synchronization accuracy, and delivery time, for industrial Ethernet specifications. Research attention has been paid to the performance analysis of cycle time [15,16,40,41,[70][71][72][73][74] and end-to-end delay [14,17,33,34,[75][76][77][78], mathematically or experimentally. Cycle time refers to the communication time required by the controller to collect and update data memories of all controlled devices and it reflects the real-time capability of the network to refresh data among the devices [72].…”