Efficient implementation of IEC 61499 function blocks

2009 IEEE Conference on Emerging Technologies & Factory Automation, 2009

The IEC 61499 function block standard proposes a new specification language for describing distributed industrial control systems. The standard specifies the use of an execution control chart (ECC) for state control, with algorithm calls for data handling. The design of complex industrial systems such as baggage handling systems can be difficult because of large state-spaces or complicated component interactions. Additionally, the flat state machines used in the standard do not provide a simple method for specifying error handling within the process's execution. State machines from synchronous languages, however, have hierarchy and concurrent constructs to aid the developer. This paper presents a Hierarchical and Concurrent extension to ECCs, which we call HCECCs, which presents new design constructs adapted from synchronous languages in order to improve system specification with function blocks. The semantics of HCECCs, which are backward compatible with the standard, are described and design using HCECCs is compared with other specification approaches.

IEEE Transactions on Computers, 2000

IEC 61499 has been endorsed as the standard for modelling and implementing distributed industrial-process measurement and control systems. The standard prescribes the use of function blocks for designing systems in a componentoriented approach. The execution model of a basic function block and the manner for event/data connections between blocks are described therein. Unfortunately, the standard does not provide exhaustive specifications for function block execution. Consequently, multiple standard-compliant implementations exhibiting different behaviours are possible. This not only defeats the purpose of having a standard, but makes verification of function block systems difficult. To overcome this, we propose synchronous semantics for function blocks, and show its feasibility by translating function blocks into a subset of Esterel, a wellknown synchronous language. The proposed semantics avoids causal cycles common in Esterel, and is proven to be reactive and deterministic under any composition. Moreover, verification techniques developed for synchronous systems can now be applied to function blocks.

2010 8th IEEE International Conference on Industrial Informatics, 2010

In order for industrial automation manufacturers to remain competitive, they must utilise modern design approaches. Existing approaches using IEC 61131 langauges are not object oriented and are difficult to reconfigure for other applications. IEC 61499 is an open standard aimed at replacing IEC 61131, adding modern design features and hardware abstraction. Therefore there is a need to migrate existing code bases using IEC 61131 technologies into the newer IEC 61499 language for future development.

WSEAS Transactions on Computers, 2009

The Function Block (FB) model was first standardized by the 1131 standard of the International Electrotechnical Commission (IEC) for programmable controllers. This standard was successfully adopted by the industry but it seems to have several constraints for the development of today's complex embedded control and automation systems. These constraints are mainly imposed by the procedural programming paradigm and the device centric approach that are adopted by the standard. The IEC to address these constraints proposed the 61499 standard that is an attempt to exploit object-orientation and the application-centric paradigm in the control and automation domain. In this paper, the FB models of 1131 and 61499 are briefly described and several unclear issues related to the programming paradigms adopted, interoperability, composability and execution semantics of these FB models are clarified. The paper focuses on the execution semantics of the 61499 standard since this is one of the most important reasons that the industry has not yet accepted this standard.

2018

Despite several architectural advantages for the challenges of future manufacturing systems, the IEC 61499 standard is currently not widely accepted by industry. One advantage of the IEC 61499 is the concept of downtimeless system evolution. An extension of this, dynamic software updating, which allows switching out running processes and deal with unplanned changes, is readily available in the programming language Erlang. This paper investigates the real-time performance of an asynchronous, parallel IEC 61499 basic function block implementation in Erlang, a functional programming language with a soft real-time, concurrent runtime environment. As a result, although hard real-time performance is not guaranteed and the runtime environment is executed on top of a regular operating system, the performance is consistent and promising for future implementations and extensions.

IEC 61499 is a standard for designing industrial control systems using function blocks. Since its publication in 2005, several run-time environments have been developed as plausible implementations. Most of them, however, are poorly suited for use in safety-critical systems, as they are unable to guarantee deterministic behaviour and predictable timing. The use of different run-time environments results in subtle behavioural differences and complicates the effort of static timing analysis. We offer an alternative solution by leveraging the model-based approach to automatically synthesize multirate synchronous programs for a multitasking environment. Our approach preserves the well-known deterministic property of synchronous programs, while facilitating static timing analysis of IEC 61499 specifications. We achieve this without the need to introduce any foreign artefact to the standard. The schedulability criterion for tasks derived using our technique is given for the rate-monotonic scheduling policy. The viability of our approach is demonstrated through a code generator, which synthesizes multirate synchronous code for multi-task execution on the µC/OS-II real-time operating system.

Industrial Informatics, 2008. …, 2008

The Function Block (FB) is proposed by IEC 61499 as the basic construct for the development of reusable, interoperable, distributed control applications. The FB designlevel construct is clearly described by the standard so various prototype development environments have been developed during last years. However, implementation model issues are not explicitly addressed and this is one of the main reasons for the fact that the FB model has not been yet adopted by industry. In this paper, we describe implementation model alternatives with main focus on the mapping of the FB network constructs to the target execution environment RTOS tasks. Schedulability analysis techniques are also considered to provide a framework for the automatic synthesis of the implementation model. The objective is to guarantee the same standard set of execution semantics independent of the execution environment.

Computer Aided Systems Theory – EUROCAST 2019, 2020

… and Factory Automation, 2006. ETFA'06. …, 2006

The International Electro-technical Commission through the 61499 standard establishes the basic infrastructure towards an open market in the control and automation domain.

Innovative Algorithms and Techniques in …, 2007

The International Electro-technical Commission (IEC) has adopted the function block (FB) concept to define the IEC 61499 standard for the development of the next generation distributed control applications. However, even though many researchers are working last years to exploit this standard in factory automation a lot of issues are still open. Except from the open issues in the design phase a lot of execution semantics are still undefined making the development of execution environments a difficult task. In this paper the semantics of the execution of the IEC 61499 Function Block model are examined, possible alternatives are investigated and existing implementations are discussed.