The objective of this paper is to reduce the development time of a PLC (programmable logic controller) by automating the task of code generation. For this Purpose, we applied t-MPSG (Timed-Message Based Part State Gra...
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The objective of this paper is to reduce the development time of a PLC (programmable logic controller) by automating the task of code generation. For this Purpose, we applied t-MPSG (Timed-Message Based Part State Graph). The t-MPSG is an extended finite state automata used to model and generate an execution module for a real-time shop floor controller system. In Our proposed method, t-MPSG is used to model the formal specification of the controller system that can be translated into textual structure. After the verification of the t-MPSG model, it can be used as an input to the plc-builder tool. The plc-builder tool is an extended version of a conventional MPSG Simulator. It can be used to translate the textual structure of the t-MPSG into an IEC standard PLC code. Finally, the generated code can be downloaded to a PLC emulator or a PLC device for the purpose of simulation and execution. The similarity in the hierarchical structure of the t-MPSG and the IEC standard PLC program has made it convenient to transform from one form to another. Furthermore, an illustration of the methodology to auto-generate IEC standard PLC code using t-MPSG is explained with a suitable example.
Growing environmental concern and increasing responsibility towards product stewardship lead companies to institute new concepts to improve the environmental performance of their products and processes. Particularly, ...
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Growing environmental concern and increasing responsibility towards product stewardship lead companies to institute new concepts to improve the environmental performance of their products and processes. Particularly, end-of-life treatment of waste electrical and electronic (WEEE) is a challenge due to rapidly changing technologies and strongly growing volumes. Disassembly has great importance as a preliminary stage for a high-quality recycling. A partly automated disassembly system could adapt to a large variety of products and different degrees of devaluation. But developing control systems still require customization for each different product and process. Testing of them is a difficult and time-consuming process, and often impossible until all the equipment has been installed. Modern simulation technology allows one to connect simulation models with real controller systems. This paper will introduce advantages of an emulation approach for the control logic development and validation. The approach will be applied on a hybrid disassembly system for LCD monitors.
This paper presents a novel application of recurrent neural network (RRN) to fault-tolerant control (FTC) of automated sequential manufacturing systems (ASMS) subject to sensor faults. Two RRNs are employed: the first...
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This paper presents a novel application of recurrent neural network (RRN) to fault-tolerant control (FTC) of automated sequential manufacturing systems (ASMS) subject to sensor faults. Two RRNs are employed: the first one acts as an I/O relations recognizer and is able to detect faulty sensors and the latter is used as an inverse model of the AMSM to compute the desired control action in a faulty case according to nominal specifications. The learning process of these networks is carried out based on training data generated from the healthy manufacturing system controlled by a programmable logic controller (PLC). Design of the proposed fault-tolerant control system (FTCS) scheme is based on utilizing the two RNNs, a reconfigurable controller and a fault decision subsystem. The design procedure of the proposed FTCS is introduced. The proposed FTCS has been implemented and tested experimentally for a benchmark industrial ASMS subject to single or multiple faulty sensors. Experimental results show the effectiveness of the procedure for a real simple plant. In addition, the results prove these features of the proposed FTCS: (a) effectively improving the faulty control system behaviors, (b) accomplishing its proper functionality in handling single and multiple sensor faults, (c) identifying the sensor faults, and (d) being advantageous in reducing the complexity of the hardware redundancy. (C) 2009 Elsevier Ltd. All rights reserved.
This paper presents a SCADA (supervisory control and data acquisition) control via PLC (programmable logic controller) for a fluid level control system with fuzzy controller. For this purpose, a liquid level control s...
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This paper presents a SCADA (supervisory control and data acquisition) control via PLC (programmable logic controller) for a fluid level control system with fuzzy controller. For this purpose, a liquid level control set and PLC have been assembled together. The PLC used in this work has no fuzzy module or software. The required fuzzy program algorithms are written by the author. Sugeno type fuzzy algorithm has been used in this study. To achieve the parameters of the membership functions, MATLAB/Simulink program has been used. PLC has been programmed using achieved fuzzy algorithm. A SCADA system has been composed for monitoring of water level in tank and position of the actuator valve. The main objective of this work is to present an implementation setup has been realized with no fuzzy logiccontroller module/software in this study. The system described in this paper is a low cost solution that is intended for control purposes. Simulation and implementation results have been compared and similar results obtained with a good degree of accuracy. (C) 2008 Elsevier Ltd. All rights reserved.
With increased use of programmable logic controllers (PLCs) in implementing critical systems, quality assurance became an important issue. Regulation requires structural testing be performed for safety-critical system...
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With increased use of programmable logic controllers (PLCs) in implementing critical systems, quality assurance became an important issue. Regulation requires structural testing be performed for safety-critical systems by identifying coverage criteria to be satisfied and accomplishment measured. Classical coverage criteria, based on control flow graphs, are inadequate when applied to a data flow language function block diagram (FBD) which is a PLC programming language widely used in industry. We propose three structural coverage criteria for FBD programs, analyze relationship among them, and demonstrate their effectiveness using a real-world reactor protection system. Using test cases that had been manually prepared by FBD testing professionals, our technique found many aspects of the FBD logic that were not tested sufficiently. Domain experts, having found the approach highly intuitive, found the technique effective. (C) 2009 Elsevier B.V. All rights reserved.
Component oriented software construction approaches have gained enormous attention in recent years. A developer has to consider functional and non-functional requirements of a customer or a market segment. For real-ti...
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Component oriented software construction approaches have gained enormous attention in recent years. A developer has to consider functional and non-functional requirements of a customer or a market segment. For real-time systems non-functional properties - such as reliability, memory consumption and performance - are at least as important as functional requirements. In our work, we focus on the prediction of worst case execution time. In this paper we deal with the problem of analyzing data flow - control flow dependencies between components with the goal of getting tight and safe WCET predictions. We use abstract interpretation for this purpose. In this paper we show how this approach can be applied to an example taken from the domain of programmable logic controllers.
Ladder logic Diagram (LLD) as the interfacing programming language of programmable logic controllers (PLCs) is utilized in modern discrete event control systems. However, LLD is hard to debug and maintain in practice....
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ISBN:
(纸本)0780394259
Ladder logic Diagram (LLD) as the interfacing programming language of programmable logic controllers (PLCs) is utilized in modern discrete event control systems. However, LLD is hard to debug and maintain in practice. This is due to many factors such as non-structured nature of LLD, the LLD programmers' background, and the huge sizes of real world LLD. In this paper, we introduce a Recurrent Neural Network (RNN) based technique for PLC program diagnosis. A manufacturing control system example has been presented to illustrate the applicability of the proposed algorithm. This method could be very advantageous in reducing the complexity in PLC control programs diagnosis because of the ease of use of the RNN compared to debugging the LLD code.
This paper presents the implementation of an automation laboratory with virtual, remote, real-time and simulated experiments for a workstation (body feed-positioning station, part of a Flexible Manufacturing System FM...
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ISBN:
(纸本)9781424447947
This paper presents the implementation of an automation laboratory with virtual, remote, real-time and simulated experiments for a workstation (body feed-positioning station, part of a Flexible Manufacturing System FMS-200) and the benefits of the application of Virtual Reality, Telematics and 3D simulation in Control Engineering education. Beyond the theoretical training based on the Internet, practical training based on the remote use of labs tends to hold an important place. The aims of all developed experiments are to improve the training of the students or engineers in the field of automation, but at the same time to offer technology for industrial developments.
This paper describes a method for model-based development of software for programmable logic controllers (PLC). The method includes modeling of a control algorithm, verifying the algorithm with respect to the requirem...
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ISBN:
(纸本)9789896740016
This paper describes a method for model-based development of software for programmable logic controllers (PLC). The method includes modeling of a control algorithm, verifying the algorithm with respect to the requirements, and automatically generating the code in one of the IEC 61131 languages. The modeling language is UML state machine diagram, and the verification tool is UPPAAL model-checking toolbox. The method has good scalability with respect to the number of the modeled objects and the ability to cope with integer values by means of variables and function blocks.
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