Efficient implementation of IEC 61499 function blocks

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.

19th Int. Conf. on Software and Systems …, 2006

Abstract: The IEC 61499 standard of the International Electro-technical Commission constitutes the first step towards an open market in the control and automation domain. The standard provides the infrastructure required for the development of the next generation agile manufacturing ...

International Journal of Modelling, …, 2008

The IEC61499 standard proposes the Function Block (FB) model for the next generation of distributed control applications. This model defines the FB type to be the basic construct in this paradigm. A control application is considered as a network of interconnected instances of FB types. These applications can be executed on one device such as a multitasking Programmable Logic Controller (PLC), but they are usually executed on a network of interconnected devices. In this paper 1 , a methodology for the development and deployment of IEC61499-based control applications on a network of interconnected devices is proposed. The methodology is based on a hybrid approach that integrates the Unified Modeling Language (UML) with the FB model, to semi automatically generate the design diagram in the form of a network of interconnected FB instances. A heuristic-based approach is described to allocate these instances to the execution environment, so as to satisfy constraints imposed by this kind of applications. A formal description of FB design models is proposed and a formal approach is described to assign FB instances to feasible OS tasks of devices while considering temporal constraints. A running example from industry is used to demonstrate the feasibility of the proposed approach.

2015 IEEE 20th Conference on Emerging Technologies & Factory Automation (ETFA), 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 subsystems , 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.

IEEE Transactions on Industrial Informatics

Automation system engineering becomes more complex, due to the trend towards more flexible, reconfigurable, and modular design approaches, like Industry 4.0. For the modeling and design of the according software, two standards are present: IEC 61131-3 and IEC 61499. In order to satisfy the requirements for modern, large scale, highly-distributed applications while also supporting still existing legacy systems, the demand for a combined development framework arises, where the best of breed tool can be chosen for a given automation task. Considering that, the IEC 61499 model is extended to allow the dual development and execution of IEC 61131-3 programs, and enabling easy and correct interaction between the two paradigms. In order to verify the validity of the chosen approach, an IEC 61499 development tool and a runtime environment is modified to support IEC 61131-3. A sample application is implemented, which comprises a pure IEC 61131-3 part with a 1 ms cycle time, a pure IEC 61499 part, and a part with interaction between both subparts, in order to evaluate possible interference between the runtime parts. Experimental results show that no interference is occurring, and the chosen development approach allows the seamless integration of IEC 61131-3 and IEC 61499 in one combined development framework. Index Terms-IEC 61499, IEC 61131, interoperability I. INTRODUCTION I N CURRENT automation systems, control software is the main driver for functionality and innovation, and therefore is a significant component. Hence, its development makes a large share of the overall costs. Considering nowadays trend towards Industry 4.0, the requirements regarding interoperability, flexibility, and reconfigurability gain importance [1]. Currently, when developing such systems, engineers have to choose between two prominent standards: the IEC 61131-3-Programmable controllers: Programming languages [2] and the IEC 61499-Function blocks [3]. The IEC 61131-3 standard's main focus was on easy-to-use programming languages, and single Programmable Logic Controller (PLC) systems, each controlling a defined section of the production process. With the move to modern large scale applications, the control software development had to deal with features like adaptability, reusability, and distributability. IEC 61131-3 evolved (e.g., object-oriented extensions, IEC 61131-5 for communication) to meet these new needs, though it was never Manuscript

Developing an embedded software solu-tion can be time consuming and challenging. Tradi-tionally, embedded software is programmed manually in proprietary computer languages such as C, C++, Java and assembly languages. In addition, most of the embedded software design environments do not cater for both microprocessors-based and Field Program-mable Gate Array (FPGA) based embedded platforms. This paper proposes s a conceptual design of a new embedded system code generator framework which is based on the IEC61499 Function Block to address the code generation issues. This involves the design and testing of the framework through the development of a prototype. An embedded system is a special-purpose, small size hardware device and software system commonly used in standalone products or added on to other equipment to enhance their functionalities. Examples include consumer products and industrial control equipment often found in manufacturing or aerospace sectors. By using embedded systems...

2019 IEEE 17th International Conference on Industrial Informatics (INDIN), 2019

IEEE International Conference on Emerging Technologies and Factory Automation, ETFA, 2012

Reusability of control code is crucial for future industrial automation in order to allow the development of high quality control systems in less time and with less cost. A key stopper for automation software reuse is the current intertwining of control logic with hardware specific code. Existing approaches that tackled such a problem could lead to improvements but will not sufficiently solve this issue. In this work we investigate a concept based on a logical grouping of I/Os to so called Instrumentation-and Control-Points and decoupling them from the control application by applying IEC 61499's adapter concept. In two industrial motivated application examples we show that this concept fulfills the requirements for increasing the reusability of control code by separating control logic from hardware specific code. Moreover, it leads to a better application software structure which is easier to maintain and to understand.

… Informatics (INDIN), 2010

The IEC 61499 is an international standard for describing industrial process-control systems. Such systems typically consist of embedded computers that interact closely with physical processes within a feedback loop. In order to correctly control these physical processes, computations in response to inputs need to be done in a timely manner. A program's worstcase reaction time (WCRT) to inputs is usually used to ensure that timing constraints are met. Unfortunately, the standard has no provisions for specifying real-time constraints. Moreover, typical implementations of IEC 61499 are tightly coupled to their runtime environments-each with possibly different semantics and temporal properties-which makes it difficult to automate the estimation of their WCRTs. We propose to adopt a synchronous model for IEC 61499 programs. This allows the programs to be executed without the need of a run-time environment. Consequently, we are able to use a novel model-checking technique to estimate the WCRT of IEC 61499 programs. Experimental results on a suite of programs show that this approach provides conservative estimates that are, on average, less than 10 percent off from the actual WCRT.

Journal of Mathematical Sciences: Advances and Applications, 2019

The applications for IEC 61499 that is standard architecture for developing the applications of distributed control and measurement in factory automation, have the connected structure of the graphical elements called BFB(basic function block), SIFB(service interface function block) and CFB(composite function block). The research on the composite function block has been regarded as important issues in implementing hierarchy, multi-functionality and simplicity of software. Nowadays many researchers have been investigated IEC61499 in the fields of the software modeling composed of basic function block and service interface function block, the transformation from IEC61131 to IEC61499 and syntactic extension of ECC of basic function block. However, work related to the mathematical modeling for IEC61499 composite function block using in designing software with hierarchical structure is still lacking. This paper presents the mathematical model for the structure and execution analysis of IEC 61499 composite function blocks by using notation of the set theory. Also a subaplication configuration algorithm is suggested for the subapplication corresponding to the composite function block. Then its effectiveness through the computation experiment of several distributed control applications is shown. The proposed model can be used effectively as a basis for analyzing a runtime environment of a software tool for designing and developing the applications.

IEEE Open Journal of the Industrial Electronics Society

This paper proposes a formal model for industrial cyber-physical systems (CPS) with distributed control based on IEC 61499 standard and supporting time-aware computations for better adaptation to the ever changing environment conditions. Main features of the model include usage of timestamps, flattening, unified and independent behaviour of function block interfaces. This allows to make correct implementation of time-aware systems and significantly simplify the construction of models for verification and simulation, as well as ensure fairness of the model and determinism of the function block system execution at a resource level. The model formalism is based on a well-known abstract state machines (ASM) notion, which can be used as an intermediate formal representation to generate a variety of models for different purposes, e.g. formal verification, and executable code. This paper exemplifies this approach by the generation of models in the SMV language. The paper discusses the time-aware computation concept and its application in a few related case studies.