What confidence can we have in a microprocessor based control or monitoring device when the safety of people or the reliability of an industrial process is a stake ? In order to provide some objective elements in answ...
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What confidence can we have in a microprocessor based control or monitoring device when the safety of people or the reliability of an industrial process is a stake ? In order to provide some objective elements in answer to this delicate question, INRS carried out a series of tests on a dozen electronic microprocessor based devices which are widely used in industry. The tests were carried out using the *** device which allows the operating safety of the equipment to be measured. The results show that certain devices designed for specific applications have a high level of safety while others including the programmable controllers do not guarantee a sufficient safety level in applications where risks are involved.
The paper enhancement actual control trends in hydropower stations. The latest concepts in modern control such as predictive maintenance and software-oriented functions are presented. Refurbishment of hydropower plant...
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The paper enhancement actual control trends in hydropower stations. The latest concepts in modern control such as predictive maintenance and software-oriented functions are presented. Refurbishment of hydropower plants is exposed as alternative to achieve updating and modernization. A list of activities to evaluate the technical state is given in order to determine modernization priorities. An application in a hydropower plant is presented, mentioning the innovations that are in operation nowadays. The control program structure is submitted, which is being applied currently in this hydropower plant. The obtained achieves with the application of these trends are furnished.
The industrial world lacks common models for the design and realization of distributed industrial-process measurement and control systems. The different models and approaches originate from private solutions of differ...
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The industrial world lacks common models for the design and realization of distributed industrial-process measurement and control systems. The different models and approaches originate from private solutions of different vendors of control equipment aimed at different customers. An approach for distributed control blocks is introduced and refined, which describes distributed control systems, hierarchical control systems, and agent systems. Since this model is currently under standardization in the International Electrotechnical Commission, widespread use can be expected and further contributions from research institutes will be helpful.
A fault-tolerant resource allocation procedure aimed at automatic modification of Petri net-based control models is presented. The recovery scheme is based on the assumption that some of the system shared resources ma...
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A fault-tolerant resource allocation procedure aimed at automatic modification of Petri net-based control models is presented. The recovery scheme is based on the assumption that some of the system shared resources may be replaced by others, e.g. in case of their malfunctioning. The method encompasses a new deadlock avoidance algorithm which guarantees deadlock freedom of the control models. Its application for development of controls for computer integrated assembly cells is shown in an example.
The Petri net graph is a powerful tool for the specification, control and analysis of discrete event systems. A well structured Petri net will provide a clear description of how a system functions. This paper describe...
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The Petri net graph is a powerful tool for the specification, control and analysis of discrete event systems. A well structured Petri net will provide a clear description of how a system functions. This paper describes the development of structured Petri nets for specification and design of control code for manufacturing systems, and discusses the implementation of such Petri nets on various controllers present in modern manufacturing systems. The usefulness of structured Petri nets for system modelling and analysis is also discussed with two practical examples where they have been used to design and implement control code on real systems.
This paper presents at first a method how to design programmes for controller systems with various net types: Grafcet, control interpreted Placer/Transition Net and Coloured Net. In the following there is a descriptio...
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This paper presents at first a method how to design programmes for controller systems with various net types: Grafcet, control interpreted Placer/Transition Net and Coloured Net. In the following there is a description of implementation methods: unfolding of the Coloured Nets, distribution, C-code or Statement List generation or a rule based method. The last method is used for realisation in hardware structures. A description of the tool system completes the paper.
This paper describes an experimental high level language-based digital drive controller for use in numerical control and robot control systems as well as in general single and multiple drive systems. The controller is...
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This paper describes an experimental high level language-based digital drive controller for use in numerical control and robot control systems as well as in general single and multiple drive systems. The controller is designed to replace conventional modular analog control systems. The controller directly executes a high level application-oriented graphic language ideal for real-time control in industrial automation. The high level language makes it possible for the user to configure the controller to his control application without difficulty, so reducing software costs significantly. A new architecture designed for high execution speed and a microprogrammed operating system allow the controller to be used for all control loops and also logic tasks in high performance multi-drive systems. Typical configurations for a d.c. motor controller are shown and experimental results are described.
This article presents a rigorous system development process promoting formal specifications of functional requirements of process control software. These specifications provide the grounds for specification-based test...
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This article presents a rigorous system development process promoting formal specifications of functional requirements of process control software. These specifications provide the grounds for specification-based testing of abstract designs and computer-assisted proofs of the conformance of program code to its requirements. Specifications are formulated in the algebraic specification language OBJ. The pertinent OBJ3 environment is used as a proof checker performing all clerical work related to correctness proofs. To illustrate the design and validation method, the specification and control program for a simple function block is provided and a few properties and assumptions about its functional behavior are proved.
The demand for stereo garages has been an urgent issue as the number of vehicles in China has been soaring these years. An intelligent control system for networked stereo garages is introduced here. Based on authors&#...
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The demand for stereo garages has been an urgent issue as the number of vehicles in China has been soaring these years. An intelligent control system for networked stereo garages is introduced here. Based on authors' design, the movement of the parking plate is controlled by a programmable logic controller (PLC). PLC sends the parking space status, the limit switch state, and the motor running parameters to the acorn RSIC machine (ARM) control system. The ARM control system then uploads the license plate recognition result and the garage operation data to the cloud platform instantly through internal network. The cloud platform would develop corresponding control strategies based on data received from the cloud portal (website and application (APP)) and the ARM controller. The test result of the system indicates that it meets the requirements of relevant technical indicators and the actual needs of users.
This elaboration presents a new device based on dynamically programmable Analog Signal Processors (dpASP) developed for hard real-time control applications. The developed programmable Analog Computer/Controller (PAC) ...
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This elaboration presents a new device based on dynamically programmable Analog Signal Processors (dpASP) developed for hard real-time control applications. The developed programmable Analog Computer/Controller (PAC) is an open hardware for a wide range of signal processing tasks. In this report the analog signal routing and filter based signal processing realized by the dpASP is presented. This research was focused on the signals form as they are processed and transferred between analog processors. The investigation is exampled by the low-pass filter(s) embedded into every analog processor. For complex signal processing tasks a few dpASP must be routed together. The dpASP chain is created for signal diagnosis and due to the limited resources of a single device. Final conclusions related to chaining analog processors are given.
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