Search Results (9)

Current fuzzing techniques for industrial control protocols (ICPs) encounter notable challenges, including model training instability, limited sample diversity, and the inability to manage complex state dependencies in protocol interactions. To address these issues, this paper presents SD-Fuzz, a state-aware fuzzing framework that integrates a discrete denoising diffusion probabilistic model (DDPM) with an online Hidden Markov Model (HMM). The discrete DDPM is designed to generate syntactically valid and diverse protocol messages using cosine noise scheduling and Denoising Diffusion Implicit Model (DDIM) sampling, while the HMM performs unsupervised learning of state transitions from real traffic to guide the creation of logically consistent multi-step interaction sequences. The framework is evaluated on three representative Modbus/TCP slave implementations. Evaluations based on 5 h benchmark campaigns across multiple independent runs indicate that SD-Fuzz achieves a mean test case recognition rate (TCRR) of 91.3% and an HMM-inferred state transition coverage of 50.1%, exhibiting statistically significant improvements over the evaluated baselines. Furthermore, an extended 8 h vulnerability mining campaign demonstrates its capability to trigger deep-seated exceptions, including buffer overflows and protocol state violations, which are typically challenging to access using traditional stateless approaches. This work illustrates the feasibility of combining diffusion-based generation with lightweight state inference for automated vulnerability discovery in industrial control systems. Directions for future work include validation on physical programmable logic controller (PLC) hardware to acquire internal code coverage feedback. Full article

Industrial PLC programming faces persistent difficulties: lengthy development cycles, low fault tolerance, and cross-platform incompatibility among vendors. While LLMs show promise for automated code generation, their direct application is hindered by the gap between ambiguous natural language and the strict determinism required by control logic. This paper proposes MPC-Coder, a dual-knowledge enhanced multi-agent system that addresses this gap. The system combines a structured knowledge graph that imposes hard constraints on process parameters and equipment specifications with a vector database that offers implementation references such as code templates and function blocks. These two knowledge sources form a symmetric complementary architecture. A closed-loop “generation–verification–repair” mechanism leverages formal verification tools to iteratively refine the generated code. Experiments demonstrate that MPC-Coder achieves 100% syntactic correctness and 78% functional consistency, significantly outperforming general-purpose LLMs. The results indicate that the complementary fusion of domain knowledge and closed-loop verification effectively enhances the reliability of code generation, offering a viable technical pathway for the reliable application of LLMs in industrial control systems. Full article

Faulty programming of control functions in Building Automation and Control Systems (BACS) might result in inefficient building operations. To reduce programming errors, an automated implementation process of control functions might be a promising solution. Recently, Building Information Modeling (BIM) contributes to digitizing building construction projects but is rarely used in the planning and implementation of control functions in BACS. The control description in BIM also remains unclear. Regarding these problems, a control documentation method for BIM and an automated control implementation approach can simplify control implementation in BACS and hence improve the building operation. In the previous work, we developed the MODI method for a structured planning process of mode-based control algorithms for building energy systems. This method showed the potential to support digitized control planning and implementation in BACS. Based on this, in this paper, we introduce a documentation method to report mode-based control algorithms in the industrial foundation class (IFC), enabling data sharing among BIM, and a software-assisted approach to automatically generate PLC codes for implementing these algorithms. The case study demonstrates the documentation of a desired mode-based control strategy for an energy supply network in IFC and the implementation of this strategy in a PLC program. In the simulation phase, we test the implemented control strategy to verify the functionalities of the PLC program. The results prove that mode-based control strategies can be fully automatically implemented in a PLC program based on IFC data. Full article

Validation is a critical stage of the equipment design process as it provides documentary evidence that the equipment is performing as per specification and ensures consistent product quality is maintained at all times. The advent of Industry 4.0 has led to a requirement for reconfigurable manufacturing systems as manufacturers adapt to an increased customer demand for personalised products. As equipment control software becomes increasingly complex to accommodate these requirements, a new approach to equipment validation is required. This paper presents a methodology for the design and validation of equipment in regulated manufacturing environments, using a model-based design platform (MathWorks^® Simulink^®) to model and digitally validate the Programmable Logic Controller (PLC) code required to control manufacturing equipment. A workflow is presented detailing the steps required to implement this approach and a demonstration model was developed as a proof of concept. Validation documentation and PLC code are automatically generated based on the system model and the functionality of the generated PLC code was successfully verified on a physical demonstrator, proving the feasibility of the proposed approach. Adoption of the approach outlined in this work would enable manufacturers in regulated industries, such as medical devices and pharmaceutical products, to rapidly design, build, reconfigure and revalidate manufacturing equipment as required to accommodate an increased demand for customised products. Full article

Regulation control for Petri nets is a control framework that allows the design of sequence controllers for automation systems in a systematic and efficient way. In order to implement this control framework, the MATLAB^® app RCPetri has been developed. In this work, the RCPetri tool functionalities are described, including model generation, automatic specification generation, automatic control design, model and control simulation, automatic translation to PLC code, and communication by Modbus TCP/IP and OPC UA. Furthermore, three examples are presented to illustrate the application of the tool and the regulation framework: an electro-pneumatic device, a process control system, and a robotic manufacturing cell under a decentralized control scheme. Full article

Within the Industry 4.0 revolution, manufacturing enterprises are transforming to intelligent enterprises constituted by Smart Manufacturing Systems (SMSs). A key capability of SMSs is the ability to connect and communicate with each other through Industrial Internet of Things technologies, and protocols with standard syntax and semantics. In this context, the GEMMA-GRAFCET Methodology (GG-Methodology) provides a standard approach and vocabulary for the management of the Operational Modes (OMs) of SMSs through the automation software, bringing a common understanding of the exchanged data. Considering the lack of tools to implement the methodology, this work introduces an online tool based on Model-Driven Engineering–GEMMA-GRAFCET Generator (GG-Generator)–to specify and generate PLCopen XML code compliant with the GG-Methodology. The proposed GG-Generator is applied to a case study and validated using Virtual Commissioning and Dynamic Software Testing. Due to the consistency obtained between the GG-Methodology and the generated PLC code, the GG-Generator is expected to support the adoption of the methodology, thus contributing to the interoperability of SMSs through the standardization of the automation software for the management of their OMs. Full article

The continuous changes of the market and customer demands have forced modern automation systems to provide stricter Quality of service (QoS) requirements. This work is centered in automation production system flexibility, understood as the ability to shift from one controller configuration to a different one, in the most quick and cost-effective way, without disrupting its normal operation. In the manufacturing field, this allows to deal with non-functional requirements such as assuring control system availability or workload balancing, even in the case of failure of a machine, components, network or controllers. Concretely, this work focuses on flexible applications at production level, using Programmable Logic Controllers (PLCs) as primary controllers. The reconfiguration of the control system is not always possible as it depends on the process state. Thus, an analysis of the system state is necessary to make a decision. In this sense, architectures based on industrial Multi Agent Systems (MAS) have been used to provide this support at runtime. Additionally, the introduction of these mechanisms makes the design and the implementation of the control system more complex. This work aims at supporting the design and development of such flexible automation production systems, through the proposed model-based framework. The framework consists of a set of tools that, based on models, automate the generation of control code extensions that add flexibility to the automation production system, according to industry 4.0 paradigm. Full article

The paper aims at describing a model-based approach to design automation logics for fault location and supply restoration in medium voltage distribution networks. The application of automation functions along medium voltage feeders and, in particular, the installation of protection devices in secondary substations mandates the design and the implementation of complex logics to coordinate the operations of this hardware in case of fault occurrences. This synchronization is realized with the exchange of IEC 61850 GOOSE messages, but the correct usage of this information must be implemented in each protection device through dedicated logics, which are not in the common out-of-the-box system configurations. To support the introduction and the design of these logics, an automata-based approach has been proposed and successfully demonstrated in a real environment in the European research project IDE4L. This formal methodology has been introduced to simplify the design phase and to standardize the logics implemented in the protection prototypes realized in the project. The same models have also been used in the implementation phase with a semi-automatic code generation procedure, considering as a target system the software programmable logic controllers (soft-PLCs), available on the protection devices. Based on the test results and the short time to set up the test bench, this approach proved to be a reliable and effective way to implement complex medium voltage (MV) automation logics such those needed in modern smart grids. Full article

Narrowband (NB) powerline communication (PLC) is extensively adopted by utilities for the communication in advanced metering infrastructure (AMI) systems. PLC technology needs to overcome channel disturbances present in certain grid segments. This study analyzes improvement proposals of the physical layer of the main narrowband PLC technologies approved by international communication organizations that are currently deployed in Europe: Powerline Intelligent Metering Evolution (PRIME) 1.3.6, PRIME 1.4, and G3-PLC, in order to improve PLC performance under channel disturbances. This thorough study is based on simulations carried out by an innovative ad hoc Virtual PLC Lab, developed by the authors, applied in replicable, fully-automated, and cost reduced test scenarios. The analysis is performed by applying standardized test methods and metrics, and by evaluating the influence of a set of representative channel disturbances defined by the European Telecommunications Standards Institute (ETSI) and selected noises generated by distributed energy resources (DER) in normal operation. PLC performance improvements in terms of equalizer curve fitting, error correction codes, and noisy subcarrier suppression mechanisms are presented. The performance gain due to each physical improvement proposal is accurately measured and compared under the same conditions in a replicable and automated test environment in order to evaluate the use of the proposals in the evolution of future PLC technologies. Full article