This paper presents a method and a tool for converting sequential function charts into function Block Diagrams in a manner that models states with the use of flip-flops. Order of evaluation is enforced through the use...
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ISBN:
(纸本)9783030306045;9783030306038
This paper presents a method and a tool for converting sequential function charts into function Block Diagrams in a manner that models states with the use of flip-flops. Order of evaluation is enforced through the use of explicit delays. Presented approach can be used when SFC programming is not directly available but the developer wants to use advantages of SFC modeling.
In recent years, sequential control systems have become complex with increasing requirement specifications. Therefore, it is important to find bugs which might be contained in a sequential control system at each devel...
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ISBN:
(纸本)9784907764432
In recent years, sequential control systems have become complex with increasing requirement specifications. Therefore, it is important to find bugs which might be contained in a sequential control system at each development phase. Currently, a main method for analyzing the system is behavior analysis. Though, we consider that it is necessary to analyze control structures of the system before behavior of that is analyzed. The control structures consist of loop, alternative and parallel structures. These structures are corresponding repeat, selection and parallel controls which are typical in control systems. We call structural analysis to detect and to distinguish these controls. By comparing both the results of the structural analysis and requirement specifications, the system can be verified. The purpose of this research is to shake out the bugs. This paper shows a method for analyzing control structures about sequential function chart elements which are defined by IEC 61131-3. Using the method, we can find the bugs, and we can fix the bugs before behavior of the system is analyzed. Therefore, we consider that structural analysis contributes improvement of productivity.
It is undeniable the benefits that the implementation of digital twins provides to industries. However, the greatest advances in this regard have been made in the definition and implementation of digital twins in disc...
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It is undeniable the benefits that the implementation of digital twins provides to industries. However, the greatest advances in this regard have been made in the definition and implementation of digital twins in discrete manufacturing industries. The development of these twins is still in its early stages in process industries. An important issue in creating digital twins to support decision-making in the process industry is to be able to describe the production procedures. This paper aims to present an Asset Administration Shell submodel that allows the representation of procedural recipes in the batch process industry based on the ISA-88 standard. This paper proposes a conceptual model to represent the sequential function chart language, which is one of the languages proposed by the mentioned standard to represent manufacturing procedure. In addition, the proposal includes a set of rules to map sequential function chart concepts into concepts belonging to the Asset Administration Shell metamodel introduced by Platform Industrie 4.0. These mapping rules would allow the implementation of tools that automatically translate existing sequential function chart models into Asset Administration Shell submodels to reuse existing knowledge for the implementation of digital twins in batch process industries. Link to graphical and video abstracts, and to code: https://***/***/transactions/article/view/9224
This paper presents an approach to realize a universal robot programming language. Currently, numerous programming languages for industrial robots exit, depending on the manufacturer of the robot. Attempts to create a...
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ISBN:
(纸本)9781728173818;9781728173801
This paper presents an approach to realize a universal robot programming language. Currently, numerous programming languages for industrial robots exit, depending on the manufacturer of the robot. Attempts to create a standardized language have failed in the past. The presence of several new providers of robots on the market increases the number of different programming languages and concepts. For this reason, it would be desirable to have a unified procedure as can be found in the field of programmable logic controllers. Here, a specification is valid, which defines certain types of programming languages. In this contribution, a lightweight robot was connected to a programmable logic controller, where the programming of the robot should be performed. For this purpose, the communication between these two partner devices was achieved using precast data structures. Concerning the programmable logic controller, function blocks were developed to operate the robot and its periphery. They include robot-based functionality, known from common robot programming languages. With regard to the robot, a client program, which interprets and executes the commands from the programmable logic controller, was implemented. Some small robot tasks were performed to show the simplicity of our approach to robot programming based on the languages of programmable logic controllers.
sequential function chart (SFC) is currently one of the design diagrams for automated control systems to capture the sequence of operations executed by the system's control software. This method grows so complex t...
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ISBN:
(纸本)0780379527
sequential function chart (SFC) is currently one of the design diagrams for automated control systems to capture the sequence of operations executed by the system's control software. This method grows so complex that locating the cause when a problem is detected becomes extremely difficult. Researchers are constantly pursuing to develop tools that eliminate the limitations and increase the design performance using SFCs. etri nets are among the most widely used tools to model and evaluate the behavior of automated control systems. Petri net control of real-world systems is achieved by mapping sensor signals and actuator commands to Petri net transitions. Being a well-defined and well-developed tool based on a mathematical formulation, PN models are used to analyze and implement real-time control for discrete industrial systems. This paper discusses a methodology to convert the SFC of an automated control system for design and analysis using the sensor-based stage Petri nets (SBSPN). Appropriate rules are suggested to convert all the I/O sensors of SFC into stages Petri net picture. A pneumatic control system is illustrated as an example to demonstrate the practical use of this technique.
作者：
J.P. KellerAutomation
University of Applied Sciences FHNW Riggenbachstr. 16 4600 Olten Switzerland
sequential function charts (SFC) according to IEC61131-3 are often not very popular in industrial automation. This is mainly due to the fact that it was not learned systematically or its capabilities were never experi...
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sequential function charts (SFC) according to IEC61131-3 are often not very popular in industrial automation. This is mainly due to the fact that it was not learned systematically or its capabilities were never experienced. The high-level interactive e-learning tool described in this contribution offers a didactically well structured step by step e-learning course, disclosing all the necessary details. A graphical SFC-editor allows the user to freely program his own SFC. The user is only restricted to predefined actions and transitions, but with the benefit that he or she can test acquired SFC with real-life plant simulations. Analysis of SFC based on Petri-Net theory and recipe control of batch plants complete the course.
This paper covers the possibility of retraining for those electrical engineering undergraduate students already having some basic digital knowledge. It gives a solution to lead the students to the microcontroller-base...
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This paper covers the possibility of retraining for those electrical engineering undergraduate students already having some basic digital knowledge. It gives a solution to lead the students to the microcontroller-based program control of complex industrial tasks with a uniform approach. It presumes that the students are familiar with combinational and sequential logic, know the hardware and software basics of microcontroller systems, and have experience in the use of C program language. Building upon these, it presents a lookup table-based control description system for simple combinational solutions to complicated sequential controls. It separately details this kind of implementation of sequential controls according to the sequential function chart (SFC) program language corresponding with the standard IEC 61131-3. For the processing of the tabular data describing the controls, it provides interpreter programs independent from the current tasks. Teaching outcomes are discussed in the final part of the paper.
Hardware failures are inevitable random events that occur in the operation life of a batch chemical plant. Based on the piping and instrumentation diagram (P&ID) of the given process and the sequentialfunction ch...
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Hardware failures are inevitable random events that occur in the operation life of a batch chemical plant. Based on the piping and instrumentation diagram (P&ID) of the given process and the sequential function chart(SFC) of its normal operating procedure, a system automaton and the corresponding "diagnoser" can be built to identify all observable fault propagation traces and, also, their root cause(s). Since the fault origin(s) of a trace may not be unique, there is a need to develop a nonconventional means to further enhance diagnostic performance. For this purpose, a novel approach is proposed in this study to synthesize the test plan of every undiagnosable trace on the basis of discrete-event system (DES) theory. In particular, all components at the failure-induced initial states and the required control specifications are first modeled systematically with automata and, then, an optimal supervisor(test plan) can be assembled accordingly so as to achieve the operation goal of differentiating the fault origins as much as possible. This proposed strategy has been tested successfully in a series of examples and the results of selected case studies are reported in this paper. (C) 2014 Elsevier Ltd. All rights reserved.
This paper describes a visual tool for developing real-time control software for distributed industrial systems. The aim of this project currently in progress, is to obtain a visual programming environment which integ...
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This paper describes a visual tool for developing real-time control software for distributed industrial systems. The aim of this project currently in progress, is to obtain a visual programming environment which integrates both the advantages of object-oriented modelling for the design and simulation of systems and the power of modern distributed control systems (i.e. computers with real-time operating systems interconnected by means of industrial real-time networks). To bridge the gap between the object-oriented system model and the implementation level, at which we have multiple parallel tasks running on a network, sequential function charts (SFCs) are used as a standard formalism [12,16] for the description of system dynamics and control software programming. (C) 1999 Elsevier Science B.V. All rights reserved.
Simulation software is used to PLC program development,Engineering and technical personnel can get rid of the shackles of PLC hardware conditions,They can be flexible and independent to design and debug program. Seque...
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ISBN:
(纸本)9783037852828
Simulation software is used to PLC program development,Engineering and technical personnel can get rid of the shackles of PLC hardware conditions,They can be flexible and independent to design and debug program. sequential function chart (SFC) is a programming method of efficient and simple in PLC program development,For complex procedures,The efficiency is very high,This paper introduces PLC program development and simulation with sequential function chart and simulation software,This method can greatly improve efficiency.
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