Event Storms in IEC 61499 Applications

The event-based IEC 61499 standard was established to complement the cycle-based IEC 61131 standard for PLC applications. It focuses on the design of an application employing a function block based approach, whereas the implementation targeting either standalone or networked embedded systems is kept transparent. The individual blocks within such a system interact with each other via event and data signals. Their execution influences the logical and temporal correctness of the respective applications. This paper investigates event storms situations where multiple events are emitted almost simultaneously with regard to the systems correctness by using an experimental setup. Furthermore, a monitoring approach is proposed that when combined with other means provides a potential solution to mitigate problematic or erroneous behavior caused by such event storms.