Evaluating XMPP Communication in IEC 61499-based Distributed Energy Applications

The IEC 61499 reference model provides an international standard developed specifically for supporting the creation of distributed event-based automation systems. Functionality is abstracted into function blocks which can be coded graphically as well as via a text-based method. As one of the design goals was the ability to support distributed control applications, communication plays a central role in the IEC 61499 specification. In order to enable the deployment of functionality to distributed platforms, these platforms need to exchange data in a variety of protocols. IEC 61499 realizes the support of these protocols via "Service Interface Function Blocks" (SIFBs). In the context of smart grids and energy applications, IEC 61499 could play an important role, as these applications require coordinating several distributed control logics. Yet, the support of grid-related protocols is a pre-condition for a wide-spread utilization of IEC 61499. The eXtensible Messaging and Presence Protocol (XMPP) on the other hand is a well-established protocol for messaging, which has recently been adopted for smart grid communication. Thus, SIFBs for XMPP facilitate distributed control applications, which use XMPP for exchanging all control relevant data, being realized with the help of IEC 61499. This paper introduces the idea of integrating XMPP into SIFBs, demonstrates the prototypical implementation in an open source IEC 61499 platform and provides an evaluation of the feasibility of the result.Comment: 2016 IEEE 21st International Conference on Emerging Technologies and Factory Automation (ETFA

On Ladder Logic Bombs in Industrial Control Systems

In industrial control systems, devices such as Programmable Logic Controllers (PLCs) are commonly used to directly interact with sensors and actuators, and perform local automatic control. PLCs run software on two different layers: a) firmware (i.e. the OS) and b) control logic (processing sensor readings to determine control actions). In this work, we discuss ladder logic bombs, i.e. malware written in ladder logic (or one of the other IEC 61131-3-compatible languages). Such malware would be inserted by an attacker into existing control logic on a PLC, and either persistently change the behavior, or wait for specific trigger signals to activate malicious behaviour. For example, the LLB could replace legitimate sensor readings with manipulated values. We see the concept of LLBs as a generalization of attacks such as the Stuxnet attack. We introduce LLBs on an abstract level, and then demonstrate several designs based on real PLC devices in our lab. In particular, we also focus on stealthy LLBs, i.e. LLBs that are hard to detect by human operators manually validating the program running in PLCs. In addition to introducing vulnerabilities on the logic layer, we also discuss countermeasures and we propose two detection techniques.Comment: 11 pages, 14 figures, 2 tables, 1 algorith

Control de la Temperatura Mediante Simulink PLC Coder y el Estándar IEC 61131

Programmable Logic Controllers (PLC) are an essential part of automated industrial production processes since their first implementation, so understanding the IEC 61131 standard and, above all, section three defines the programming languages allowed by PLCs take relevance over time. This work describes each of the programming languages described in IEC 61131-3. Additionally, it implements an automation system based on Structured Text with a Human Machine Interface (HMI). The plant is a temperature process with a classic control system developed using Matlab tools, such as System Identification, PID Tuner, and Simulink. For the HMI, was implemented the Codesys Group industrial automation process platform. The Simulink PLC Coder toolbox allows the strengthening of the connection between the control system and the HMI.  This program generates the Structured Text of a control system developed in Simulink. For the analysis of results, the control behavior compared between Simulink and the system produced in Codesys Group obtained an error of less than 0.34 %.Los Controladores Lógicos Programables (PLC) son una parte esencial de los procesos de producción industrial automatizada desde su primera implementación, por lo que la comprensión del estándar IEC 61131 y, sobre todo, la sección tres que define los lenguajes de programación que permiten que los PLC toman relevancia con el tiempo. Este trabajo describe cada uno de los lenguajes de programación descritos en el estándar IEC 61131-3. Además, implementa un sistema de automatización basado en texto estructurado con una interfaz hombre-máquina (HMI). La planta es un proceso de temperatura con un sistema de control clásico desarrollado con herramientas de Matlab, como System Identification, PID Tuner y Simulink. Para la HMI, se implementó la plataforma de procesos de automatización industrial del Grupo Codesys. El toolbox Simulink PLC Coder permite reforzar la conexión entre el sistema de control y el HMI. Este programa genera el Texto Estructurado de un sistema de control desarrollado en Simulink. Para el análisis de resultados, el comportamiento del control comparado entre Simulink y el sistema producido en Codesys obtuvo un error inferior al 0,34 %

A game-based approach to the teaching of object-oriented programming languages

Students often have difficulties when trying to understand the concepts of object-oriented programming (OOP). This paper presents a contribution to the teaching of OOP languages through a game-oriented approach based on the interaction with tangible user interfaces (TUIs). The use of a specific type of commercial distributed TUI (Sifteo cubes), in which several small physical devices have sensing, wireless communication and user-directed output capabilities, is applied to the teaching of the C# programming language, since the operation of these devices can be controlled by user programs written in C#. For our experiment, we selected a sample of students with a sufficient knowledge about procedural programming, which was divided into two groups: The first one had a standard introductory C# course, whereas the second one had an experimental C# course that included, in addition to the contents of the previous one, two demonstration programs that illustrated some OOP basic concepts using the TUI features. Finally, both groups completed two tests: a multiple-choice exam for evaluating the acquisition of basic OOP concepts and a C# programming exercise. The analysis of the results from the tests indicates that the group of students that attended the course including the TUI demos showed a higher interest level (i.e. they felt more motivated) during the course exposition than the one that attended the standard introductory C# course. Furthermore, the students from the experimental group achieved an overall better mark. Therefore, we can conclude that the technological contribution of Sifteo cubes – used as a distributed TUI by which OOP basic concepts are represented in a tangible and a visible way – to the teaching of the C# language has a positive influence on the learning of this language and such basic concepts

Control de la Temperatura Mediante Simulink PLC Coder y el Estándar IEC 61131

Programmable Logic Controllers (PLC) are an essential part of automated industrial production processes since their first implementation, so understanding the IEC 61131 standard and, above all, section three defines the programming languages allowed by PLCs take relevance over time. This work describes each of the programming languages described in IEC 61131-3. Additionally, it implements an automation system based on Structured Text with a Human Machine Interface (HMI). The plant is a temperature process with a classic control system developed using Matlab tools, such as System Identification, PID Tuner, and Simulink. For the HMI, was implemented the Codesys Group industrial automation process platform. The Simulink PLC Coder toolbox allows the strengthening of the connection between the control system and the HMI.  This program generates the Structured Text of a control system developed in Simulink. For the analysis of results, the control behavior compared between Simulink and the system produced in Codesys Group obtained an error of less than 0.34 %.Los Controladores Lógicos Programables (PLC) son una parte esencial de los procesos de producción industrial automatizada desde su primera implementación, por lo que la comprensión del estándar IEC 61131 y, sobre todo, la sección tres que define los lenguajes de programación que permiten que los PLC toman relevancia con el tiempo. Este trabajo describe cada uno de los lenguajes de programación descritos en el estándar IEC 61131-3. Además, implementa un sistema de automatización basado en texto estructurado con una interfaz hombre-máquina (HMI). La planta es un proceso de temperatura con un sistema de control clásico desarrollado con herramientas de Matlab, como System Identification, PID Tuner y Simulink. Para la HMI, se implementó la plataforma de procesos de automatización industrial del Grupo Codesys. El toolbox Simulink PLC Coder permite reforzar la conexión entre el sistema de control y el HMI. Este programa genera el Texto Estructurado de un sistema de control desarrollado en Simulink. Para el análisis de resultados, el comportamiento del control comparado entre Simulink y el sistema producido en Codesys obtuvo un error inferior al 0,34 %

Low-cost Industrial controller based on the Raspberry Pi platform

Mestrado de dupla diplomação com o Centro Federal de Educação Tecnológica Celso Suckow da Fonseca - CEFET/RJThe low-cost automation field exhibits the need of innovation both in terms of hardware and software. There is a lack of devices that allow the development of control logic that is free from restrictions of domain-specific communication platforms and at the same time able to provide the capabilities aligned to the Industry 4.0 requirements. The objective of this work is to develop an inexpensive, small Industrial Controller that supports the execution of programs in different industrial programming languages. So, it is intended to develop, manufacture and control a low-cost but powerful Industrial Controller based on the use of the single-board computer Raspberry Pi. The study described in this document was carried out on the creation of a hardware platform that is capable of integrating with software frameworks compatible with standards updated and widely used in the industrial automation field. IEC 61131-3 is employed displaying the ease of use and implementation alongside multiple well established programming languages for automation through the OpenPLC platform while IEC 61449 is employed through the 4DIAC framework that has a clear and objective environment capable of providing the appropriate tools for implementation of a distributed control. It is employed the single-board computer Raspberry Pi, a robust device with adequate processing power and communication capability for the elaboration of a platform in the low-cost automation scope. The elaboration of the Industrial Shields, responsible for providing the controller I/O interface took into consideration maintenance concerns of controller integrity through the application of galvanic isolation in the automaton input and output sections. The proposed platform was successfully tested in an automation system prototype comprising Fischertechnik’s Punching Machine being possible to develop the control logic using IEC 61131-3 and IEC 61499.O campo de automação de baixo custo demonstra a necessidade de inovação em termos de hardware e software. Há uma falta de dispositivos que permitem o desenvolvimento de lógica de controle livre de restrições de plataformas de comunicação específicas de domínio e, ao mesmo tempo, capazes de fornecer os recursos alinhados aos requisitos da Indústria 4.0. O objetivo deste trabalho é desenvolver um pequeno Controlador Industrial de baixo custo que suporte a execução de programas em diferentes linguagens de programação industrial. Assim, pretende-se desenvolver, fabricar e controlar um Controlador Industrial de baixo custo, mas poderoso, baseado no uso do computador de placa única Raspberry Pi. O estudo descrito neste documento foi realizado na criação de uma plataforma de hardware que é capaz de se integrar com frameworks de software compatíveis com padrões atualizados e amplamente utilizados na área de automação industrial. A IEC 61131-3 é empregada exibindo a facilidade de uso e implementação juntamente com várias linguagens de programação bem estabelecidas para automação através da plataforma OpenPLC enquanto a IEC 61449 é empregada através da estrutura 4DIAC que possui um ambiente claro e objetivo capaz de fornecer as ferramentas apropriadas para implementação de um controle distribuído. É empregado o computador de placa única Raspberry Pi, um dispositivo robusto com capacidade de processamento e capacidade de comunicação adequados para a elaboração de uma plataforma no escopo de automação de baixo custo. A elaboração dos industrial shields, responsáveis por fornecer a interface de I/O do controlador levou em consideração as preocupações de manutenção da integridade do controlador através da aplicação de isolação galvânica nas seções de entrada e saída do autômato. A plataforma proposta foi testada com sucesso em um protótipo de sistema de automação compreendendo a Punching Machine da Fischertechnik sendo possível desenvolver a lógica de controle usando IEC 61131-3 e IEC 61499