Software development for programmablelogical controllers is usually based on low-level languages such as the instruction list or the ladder diagram. At the same time, the programmer looks at a machine or an assembly ...
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ISBN:
(纸本)0818676140
Software development for programmablelogical controllers is usually based on low-level languages such as the instruction list or the ladder diagram. At the same time, the programmer looks at a machine or an assembly system in a bit-oriented way;he translates the operational sequences into logical and/or time based combinations of binary signals described by the means of Boolean algebra. This classical method causes a lot of problems in reality so it should be improved. It is the aim of the report to show a way developing PLC-software graphically and interactively within a Virtual Reality (VR) based system (VPLC).
The paper presents the design process of a control system for a line which manufactures metallic parts for the automotive industry. The manufacturing line is designed so that it can produce several product models. The...
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The paper presents the design process of a control system for a line which manufactures metallic parts for the automotive industry. The manufacturing line is designed so that it can produce several product models. The control system, based on a programmablelogic controller (PLC), is designed to allow on-the-fly reconfiguration of the line based on the recipe selected by the operator. Equally, the hardware configuration and the PLC program allow the further development of the manufacturing line by adding new stations (and obviously new recipes). By incorporating into the control system modular programming techniques, a large amount of safety measures, tools necessary to ensure product traceability and a modern human-machine interface (HMI), the design ensures high efficiency of the manufacturing line, a high level of safety of the operators and of the plant, compliance with current quality requirements and the possibility to expand the line for extending the product range without considerable effort.
programmable logic controllers (PLC) are key components in modern packaging automation systems. But their success has led to the presence of a broad range of brands and models, each one with its own and unique feature...
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ISBN:
(纸本)9781479977277
programmable logic controllers (PLC) are key components in modern packaging automation systems. But their success has led to the presence of a broad range of brands and models, each one with its own and unique features, but also with its own environment for software development. This situation has some major drawbacks: it is very difficult to upgrade an installation by changing the PLC, maintenance costs rise with the multiplicity of PLC brands in a given factory, and production parameters must be changed when the production is changed to a machine with a different PLC. In this paper, a first step is presented to address such a situation: instead of developing the same program from scratch for each different PLC brand, a unique program is stored using the PLCopen XML standard. When the program must be ported to a given PLC, an automatic tool, the postprocessor, generates the final code that has to be downloaded to the target PLC. In this paper the PLC tool adapter is presented and an example is shown for three of the major PLC brands present in the packaging industry such as Siemens, Schneider Electric and ABB.
Current supervisory control and data acquisition (SCADA) systems do not have adequately tailored security solutions. programmable logic controllers (PLCs) in SCADA systems are particularly vulnerable due to a lack of ...
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ISBN:
(纸本)9783642357640
Current supervisory control and data acquisition (SCADA) systems do not have adequately tailored security solutions. programmable logic controllers (PLCs) in SCADA systems are particularly vulnerable due to a lack of firmware auditing capabilities. Since a PLC is a field device that directly connects to a physical system for monitoring and control, a compromise of its firmware could have devastating consequences. This paper describes a tool developed specifically for verifying PLC firmware in SCADA systems. The tool captures serial data during firmware uploads and verifies it against a known good firmware executable. It can also replay captured data and analyze firmware without the presence of a PLC. The tool does not require any modifications to a SCADA system and can be implemented on a variety of platforms. These features, along with the ability to isolate the tool from production systems and adapt it to various architectures, make the tool attractive for use in diverse SCADA environments.
Virtual environments for educational and training purposes have become a trend in the last decade as an alternative to traditional pedagogic methods. In this work, a framework for the design of a virtual training syst...
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ISBN:
(数字)9798350331493
ISBN:
(纸本)9798350331493
Virtual environments for educational and training purposes have become a trend in the last decade as an alternative to traditional pedagogic methods. In this work, a framework for the design of a virtual training system from a programmablelogic Controller (PLC) and its integration in a virtual environment based on Unity and Computer Aided Design (CAD) modeling is presented. The system presents a 3D environment of an Automation and Control Lab and virtualization of a PLC interface with interactive digital and analog inputs and outputs. A Ladder Diagram (LD) interface for the user to address the mentioned PLC elements is also presented. A System Usability Scale (SUS) test was carried out to determine system functionality and usability, the system and the test were applied to a group of 65 participants. 15 participants evaluated the 3D environment while the other 50 evaluated the PLC and the LD interface. The obtained results show an average of 73.19 and 75.8 points respectively in the SUS tests, making it possible to determine that the usability and functionality of the systems are in a good position.
programmable logic controllers (PLCs) play critical roles in industrial control systems (ICS). Providing hardware peripherals and firmware support for control programs (i.e., a PLC's "payload") written i...
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ISBN:
(纸本)9781538645864
programmable logic controllers (PLCs) play critical roles in industrial control systems (ICS). Providing hardware peripherals and firmware support for control programs (i.e., a PLC's "payload") written in languages such as ladder logic, PLCs directly receive sensor readings and control ICS physical processes. An attacker with access to PLC development software (e.g., by compromising an engineering workstation) can modify the payload program and cause severe physical damages to the ICS. To protect critical ICS infrastructure, we propose to model runtime behaviors of legitimate PLC payload program and use runtime behavior monitoring in PLC firmware to detect payload attacks. By monitoring the I/O access patterns, network access patterns, as well as payload program timing characteristics, our proposed firmware-level detection mechanism can detect abnormal runtime behaviors of malicious PLC payload. Using our proof-of-concept implementation, we evaluate the memory and execution time overhead of implementing our proposed method and find that it is feasible to incorporate our method into existing PLC firmware. In addition, our evaluation results show that a wide variety of payload attacks can be effectively detected by our proposed approach. The proposed firmware-level payload attack detection scheme complements existing bump-in-the-wire solutions (e.g., external temporal-logic-based model checkers) in that it can detect payload attacks that violate realtime requirements of ICS operations and does not require any additional apparatus.
In this paper we develop an approach to interactive verification of programmable logic controllers which often serve as controllers in safety critical systems and hence need thorough verification. As a verification to...
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ISBN:
(纸本)9783319247045;9783319247038
In this paper we develop an approach to interactive verification of programmable logic controllers which often serve as controllers in safety critical systems and hence need thorough verification. As a verification tool we use the KIV system, whereas the formalization is done in modal Kleene algebra. We first prove a bunch of theorems from modal Kleene algebra in KIV, subsequently translate the desired properties of a program for a programmablelogic controller in modal Kleene algebra, and finally prove these encoded properties interactively with KIV.
programmable logic controllers (PLCs) are widely applied to control safety critical systems. Efficient formal and non formal methods to detect faulty behavior have been developed, but finding the cause of the buggy be...
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ISBN:
(纸本)9783642142604
programmable logic controllers (PLCs) are widely applied to control safety critical systems. Efficient formal and non formal methods to detect faulty behavior have been developed, but finding the cause of the buggy behavior is often still a manual process. Automatic fault localization for PLCs is studied in this paper. Methods for automated debugging are analyzed and compared with respect to accuracy and run time. The experimental results on industrial models show a high accuracy at low run time costs.
We give timed automaton models for a class of programmablelogic Controller (PLC) applications, that are programmed in a simple fragment of the language Instruction Lists as defined in the standard IEC 1131-3. Two dif...
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ISBN:
(纸本)0769502407
We give timed automaton models for a class of programmablelogic Controller (PLC) applications, that are programmed in a simple fragment of the language Instruction Lists as defined in the standard IEC 1131-3. Two different approaches for modelling timers are suggested, that lead to two different timed automaton models. The purpose of this work is to provide a basis for verification and testing of real-time properties of PLC applications. Our work can be seen in broader context: it is a contribution to methodical development of provably correct programs. Even if the present PLC hardware will be substituted by e.g. Personal Computers, with a similar operation mode, the development and verification method will remain useful.
Functional and nonfunctional validation is an important task in complex embedded system developments. This paper proposes a method of applying model checking techniques to validate programable logiccontrollers (PLCs)...
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ISBN:
(纸本)9781424419944
Functional and nonfunctional validation is an important task in complex embedded system developments. This paper proposes a method of applying model checking techniques to validate programable logiccontrollers (PLCs). Abstraction is used to ameliorate the state explosion problem. The experiment results of an industry application demonstrate the effectiveness of our approach.
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