Charging and control system of a high-energy capacitor bank storage is described. The capacitor bank is used to supply power to magnetic coils in experiments on magnetic controlled fusion and in similar applications. ...
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Charging and control system of a high-energy capacitor bank storage is described. The capacitor bank is used to supply power to magnetic coils in experiments on magnetic controlled fusion and in similar applications. The capacitor bank is composed of ten sections of 100 IK-6-150 capacitors (6 kV, 150 mu F) each, connected in parallel with a total stored energy of as high as 2.7 MJ. Charging occurs using inverters and stepup transformers developed by the Budker Institute of Nuclear Physics. The general description and functional diagrams of the energy storage are presented and the control electronics of the inverters is described in detail. The general control system of the capacitor bank is based on a programmable controller that performs the basic charging algorithm, off-line control of the operating parameters, and handling of various extraordinary situations. The capacitor bank is used in experiments on microwave plasma heating and maintains the magnetic field stability of similar to 2% during the whole plasma discharge (5 ms) with a current amplitude of up to 32 kA in the coils.
In most industrial plants, there is a strong drive to provide business applications with some access to real-time data generated from process control systems. Often, this has been in the form of a process historian da...
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In most industrial plants, there is a strong drive to provide business applications with some access to real-time data generated from process control systems. Often, this has been in the form of a process historian database server connected to both the distributed control systems/programmablelogic controller (DCS/PLC) systems and the business users. It can also take many other forms such as remote X-Windows sessions from the DCS, or direct file transfers from PLCs to users spreadsheets. Regardless of the method, it involves a network connection to both the process and the business side. These network connections are increasingly Ethernet based on both sides, rather than proprietary industrial protocols. At the same time, most control systems now use Ethernet networking as a critical component of their system architecture. This can be for controller-to-controller communications, controller-to-operator console communications or even I/O-to-controller communications. Losing any of these links will directly impact production.
THE USE OF INTERCONNECTED microprocessors in industrial systems has grown exponentially over the past decade. Deployed for process control in programmable logic controllers (PLCs) and distributed control systems (DCSs...
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THE USE OF INTERCONNECTED microprocessors in industrial systems has grown exponentially over the past decade. Deployed for process control in programmable logic controllers (PLCs) and distributed control systems (DCSs) for many years, they have now moved into intelligent electronic devices (IEDs) in applications such as substations, motor control centers (MCCs), and heat trace systems. The concern is that their connecting networks have grown as well, usually without much attention to the scurity ramifications. Intrusions - intentional and unintentional - can cause safety, environmental, production, and quality problems. This article looks at the process of assessing the current security situation, dealing with existing problems, and planning for future network growth.
programmablelogic controller (PLC) input/output (I/O) devices offer users new ways to improve control of machines in a cost-effective manner. One of the key trends in I/O subsystems is a wider availability of unbundl...
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programmablelogic controller (PLC) input/output (I/O) devices offer users new ways to improve control of machines in a cost-effective manner. One of the key trends in I/O subsystems is a wider availability of unbundled products, like distributed `rack,' `block,' `direct' I/O devices that are mated to alternative `brains,' such as a personal computer. `Open' standards promote inter-vendor product compatibility. This allows customers to keep the advantages of compact, rugged PLC I/O modules where appropriate and to access more open, flexible, or advanced programming and integration environments.
The critical infrastructure, which includes the electric power grid, railroads and water treatment facilities, is dependent on the proper operation of industrial control systems. However, malware such as Stuxnet has d...
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The critical infrastructure, which includes the electric power grid, railroads and water treatment facilities, is dependent on the proper operation of industrial control systems. However, malware such as Stuxnet has demonstrated the ability to alter industrial control system parameters to create physical effects. Of particular concern is malware that targets embedded devices that monitor and control system functionality, while masking the actions from plant operators and security analysts. Indeed, system security relies on guarantees that the assurance of these devices can be maintained throughout their lifetimes. This paper presents a novel approach that uses timing-based side channel analysis to establish a unique device fingerprint that helps detect unauthorized modifications of the device. The approach is applied to an Allen Bradley ControlLogix programmablelogic controller where execution time measurements are collected and analyzed by a custom anomaly detection system to detect abnormal behavior. The anomaly detection system achieves true positive rates of 0.978-1.000 with false positive rates of 0.033-0.044. The test results demonstrate the feasibility of using timing-based side channel analysis to detect anomalous behavior in programmable logic controllers. Published'by Elsevier B.V.
One of the technological innovations recently released by several PLC manufacturers is single-board PLC processors with an industry-compatible (nonproprietary) bus interface. These single-board PLCs (SBPLCs) have typi...
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One of the technological innovations recently released by several PLC manufacturers is single-board PLC processors with an industry-compatible (nonproprietary) bus interface. These single-board PLCs (SBPLCs) have typically been produced with a VMEbus form factor and bus interface, plus an onboard proprietary interface to the particular manufacturer's distributed I/O family. Using these processors, it is possible to create DCS systems that incorporate all of the advantages of both technologies.
Power Line Carrier (PLC) is a well-known technique for communicating RF signals over power lines. With present technology, it is difficult to control mutual interference of PLC signals because of the expense associate...
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Power Line Carrier (PLC) is a well-known technique for communicating RF signals over power lines. With present technology, it is difficult to control mutual interference of PLC signals because of the expense associated with RF filter components which have to withstand the high current and high voltage of the 60 Hz power. Accordingly, conventional practice limits interference by spectral allocation using propagation losses to control interference between similar frequency bands, thus being wasteful of finite spectral resources. This paper describes a new technique for adaptive interference cancellation that has the potential of providing cost-effective interference suppression, thereby freeing up the PLC frequency band for future expansion of services. A general theory of adaptive cancellation for this application is presented with particular attention paid to several problem areas: error sensing, cancellation bandwidth, and circuit design.
programmablelogic Controller (PLG) is extensively used in industries for controlling sequence of actions of the process since last two decades. Hence we have decided to develop PLC based sequential batch process cont...
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programmablelogic Controller (PLG) is extensively used in industries for controlling sequence of actions of the process since last two decades. Hence we have decided to develop PLC based sequential batch process control system of our laboratory. The sequence of process flow is decided for controlling the parameters like level and temperature. The brain of the system is PLC. Appropriate hardware for interfacing the process to the controller is developed for controlling the level and temperature of the process. For controlling sequence of actions ladder diagram is developed. The program minimizes shut down by providing recycle under certain condition to establish normal operation before checking out. Timer provides precise timings. Finally this system is factory programmable.
In this paper, a fault diagnosis system-programmablelogic controller (FDS-PLC) is developed and discussed, regarding the improvement of reliability of PLC systems. Traditional approaches to improve reliability of the...
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In this paper, a fault diagnosis system-programmablelogic controller (FDS-PLC) is developed and discussed, regarding the improvement of reliability of PLC systems. Traditional approaches to improve reliability of the fault diagnose functions of PLC are not conscious of the fact: system developers and programmers are not able to identify every fault that may occur during the system's lifetime. In order to conquer this problem, a FDS-PLC design that establishes and perfects a specification model of the PLC system is introduced. Firstly, FDS-PLC collects and transmits diagnosis data in surplus kernel time of the embedded processor;therefore, it does not decrease the responding speed of the system. Secondly, a finite state machine (FSM) built on PC is applied to construct the specification model and report faulty states to the system operator. Finally, the system is endowed with learning ability by perfecting the specification model. The application of FDS-PLC is further illustrated by an example on an elevator control system experimental platform.
To respond rapidly to the highly volatile market, the reconfigurable manufacturing systems (RMS) have brought forward challenging issues. First of all there is a need to build a formal model of a manufacturing configu...
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To respond rapidly to the highly volatile market, the reconfigurable manufacturing systems (RMS) have brought forward challenging issues. First of all there is a need to build a formal model of a manufacturing configuration. Second it has to be rather easy to derive the models associated to the manufacturing configuration changes (reconfiguration) from such an initial model. An off-line method of rapid design of an optimal logic control law (configuration) based on Petri net (PN) is presented in this paper. From a controlled system modeling point of view, the main characteristics of the level 1 of the CIM architecture are depicted. Subsequently, the formal tool used in the automated planning field is extended to provide a controlled system model. The concept of operation is structured in order to introduce the behavioral properties of the operations. A four-step method is then proposed to design a logic control law that satisfies several goals: reduction of the lead time, satisfaction of the work orders objectives, minimization of the time cycle. Finally, the proposed design method is illustrated on a manufacturing cell. (C) 2012 Elsevier Ltd. All rights reserved.
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