A Real-Time Semantics for the IEC 61499 standard
Ref: CISTER-TR-150903 Publication Date: 8 to 11, Sep, 2015
A Real-Time Semantics for the IEC 61499 standardRef: CISTER-TR-150903 Publication Date: 8 to 11, Sep, 2015
The IEC 61499 standard provides an executable model for distributed control systems in terms of interacting function blocks. However, the current IEC 61499 standard lacks appropriate timing semantics for the speciﬁcation of timing requirements, reasoning on timing properties at the model level, and for the timing veriﬁcation of a speciﬁc deployment. In this paper we address this fundamental shortcoming by proposing Real-Time-4-FUN, a real-time semantics for IEC 61499. The key property is the preservation of non-determinism, allowing us to reason on (and verify) timing properties at the model level without assuming any speciﬁc scheduling policy or stipulating speciﬁc order of execution for the deployment. This provides for a clear separation of concerns, where the designer can focus on properties of the application prior to, and separately from, deployment veriﬁcation. The proposed timing semantics is backwards compatible to the current standard, thus allow for reuse of existing designs. The transitional property allows timing requirements to propagate to downstream sub-systems, and can be utilized for scheduling both at device and network level. Based on a translation to RTFM-tasks and resources, IEC 61499 the models can be analyzed, compiled and executed. As a proof of concept the timing semantics has been experimentally implemented in the RTFM-core language and the accompanying (thread based) RTFM-RT run-time system.
20th IEEE International Conference on Emerging Technologies & Factory Automation (ETFA 2015).