In modern industrial applications, the complexity of control software is increasing while its execution may be distributed to numerous small devices. The standard IEC 61499 fosters designing distributed control applications by defining a platform-independent application model that can be mapped to numerous hardware components. Applications though need to be designed for distribution, as comparing three implementation designs of a running example indicated. We propose the usage of a distributed architectural pattern for applications with parallel paths. Metrics confirm a reduced complexity compared to purely hierarchical designs.

Accurate flow measurement is a ubiquitous task in fields such as industry, medical technology, or chemistry; it remains however challenging due to small measurement ranges or erosive flows. Inspiration for possible measurement methods can come from nature, for example from the lateral line organ of fish, which is comprised of hair cells embedded in a gelatinous cupula. When the cupula is deflected by water movement, the hair cells generate neural signals from which the fish gains an accurate representation of its environment. We built a flow sensor mimicking a hair cell, but coupled it with an optical detection method. Light is coupled into a PDMS waveguide that consists of a core and a cladding with a low refractive index contrast to ensure high bending sensitivity. Fluid flow bends the waveguide; this leads to a measurable light loss. The design of our sensory system allows flow measurement in opaque and corrosive fluids while keeping production costs low. To prove the measurement concept, we evaluated the light loss while (a) reproducibly bending the fiber with masses, and (b) exposing the fiber to air flow. The results demonstrate the applicability of an optical fiber as a flow sensor.

The IEC 61131-3 standard was initially established to define a common software architecture and programming languages for PLCs produced by various manufacturers, leading to its widespread adoption since 1993. Since then, it has been a cornerstone in the industrial automation domain. Building upon this foundation, the IEC 61499 standard was developed to enhance the design and implementation of distributed control systems by incorporating advanced concepts from distributed systems and software engineering such as encapsulation, separation of control logic from communication infrastructure, and independent development of software components from their hardware deployment. While IEC 61499 introduces novel approaches, it also incorporates and extends key elements from IEC 61131-3, including function blocks, programming languages, and basic data types. Despite the advantages offered by the IEC 61499 standard, its adoption is still limited largely due to historical precedence, industry familiarity, better tool and vendor support, and the risk-averse nature of the industrial automation market. The migration or re-engineering effort from an existing IEC 61131-based automation system to IEC 61499 also faces challenges because it typically retains the underlying programming paradigms of IEC 61131-3. The contribution of this paper is to identify the pitfalls associated with migrating PLC control code from IEC 61131-3 based automation systems to IEC 61499. For this purpose, we conducted a systematic literature review that address these identified migration pitfalls. We then synthesized the findings from the literature and provided a summary and research directions for addressing these pitfalls.

Complex processes require the cooperation of a variety of subsystems, such as robots, autonomous vehicles, and human-operated devices. These so-called mixed-fleet systems are found in logistics and production use cases, which also demand a high flexibility. Hence, the choreography that orchestrates the involved systems must be adaptable and reconfigurable. Enabling to add or remove subsystems flexibly during runtime requires a strong decoupling, which is found in multi-agent systems. In this paper, we explore a model-driven engineering process for service choreographies of flexible, heterogeneous, and autonomous mixed-fleet systems. Each complex process is decomposed into services and tasks, which are flexibly assigned to resources. The resulting layered service-oriented architecture is realized as an event-based system. We define requirements for modeling services, tasks, and events and evaluate different modeling language based on their applicability for each layer, i.e., BPMN, SysML/UML, and IEC 61499. We demonstrate and evaluate our architecture using a logistics use case scenario. The results show that these languages are suitable candidates for modeling event-based process models and that the diagrams can be used to capture service choreography models for decentralized systems. Future work will investigate how these models can be validated comprehensively and used for system implementation.