Master-slave Concept Research Articles

Reliability and Profit Evaluation of a PLC Hot Standby System Based on a Master-Slave Concept and Two Types of Repair Facilities

Programmable Logic Controllers (PLC) are frequently used by a good number of companies like steel plants, biscuit manufacturing companies, etc. Various plants/companies use two PLC at a time: one operative, and the other as a hot standby to avoid big losses. Analysis of the reliability, and profit of a hot standby PLC system is of great importance; and hence the present paper examines such a system wherein two PLC are working in master-slave fashion. Initially, the master unit is operative, and the slave unit is in hot standby. The slave unit can also fail, but with a lower failure rate than the master unit. The master unit has the priority of operation ∓mp;mp;mp;mp;mp;mp;mp;mp;mp;mp;mp;mp;mp;mp;mp;mp;mp;mp;mp;mp;mp;mp;mp;mp;mp;mp;mp;mp;mp;mp;mp;mp;mp;mp;mp;mp;mp;mp;mp;mp;mp;mp;mp;mp;mp;mp;mp;mp; repair over the slave unit. While operating, the latest information from the master unit keeps on transferring to the slave unit. There are three types of failure: minor, major-repairable, and major-irreparable. The ordinary repairman who stays with the system repairs the minor failures. The expert repairman who is available upon demand repairs the major failures. Various measures of the system effectiveness, such as the mean time to system failure, steady-state availability, busy period of the ordinary as well as expert repairmen, expected number of replacements, etc. are obtained by using semi-Markov processes, and regenerative point Techniques. Profit incurred to the system is evaluated, and a graphical study is also made. Real data from an industrial application is used in this study.

Advanced Power Supplies designed for Plasma Deposition and Etching

AbstractPlasma deposition and etching processes are used for a wide range of applications as for example the production of semiconductor circuits, flat panel displays, solar cells, architectural glass and data storage media. To fulfill the special needs of each single process stable DC, MF and RF process power ranging from 50W to 200kW is needed.All generators need a high precision process control and a supreme arc management with adaptable parameters to provide minimal disturbances in the plasma process and to obtain optimized results in terms of film quality, homogeneity and uniformity over the whole substrate. The fast and flexible arc handling leads to an improvement in the film quality by minimizing flaws and defects and enables the use of very high sputter rates.To fit DC process demands a new concept for a modular DC system has been realized where up to four 30kW modules can be combined using master slave concept. The arc management and control of the DC module has an intelligent control enabling arc detection times of less than 1μs and a residual energy delivered to the process of only 6 mJ per kW.For MF processes a fast and effective arc management is an even more important tool for keeping reactive processes stable. The new generation of MF power supplies enables arc detection and shut off times of 5μs with a residual energy delivered to the process of only 5 mJ per kilowatt. This yields the additional advantage that even when the cathode material is almost used up and consequently the arc probability increases, the low residual energy values contribute to an extended service life of the cathode and to better utilization of the target material.Essentially, the outstanding feature of effective arc management is an undisturbed plasma during the whole operation time. The fast arc suppression minimizes the interruption in the sputtering process to negligibly small values. However, because arcs also serve to remove unwanted materials on the cathode, power supplies must be able to control and regulate the arc energy precisely. MF power supplies are available for process power up to 200kW.RF systems are based on two different concepts to fit the broad power range between 50W and 50kW. For the low energy range a fully transistorized and μC‐controlled RF generator was developed. This generator has been designed for a max. power of 3kW. Important features are the compact size, robustness, reliability and easy maintenanceTo have a cost effective design for a high power RF generator in this power range an oscillator ‐ amplifier concept has been chosen with a solid state driver in combination with a tube type end stage amplifier.To fit todays demands for advanced etching a dual frequency system consisting of a 13.6 MHz and a 3.4 MHz unit was developed. This enables the possibility to separately control plasma density and ion energy of the discharge.

A novel mathematical analysis for predicting master–slave synchronization for the simplest quadratic chaotic flow and Ueda chaotic system with application to communications

A master–slave concept of chaotic system synchronization is examined and applied in secure data transmission. In most situations when examining this type of synchronization one considers the asymptotic stability of the particular system via Lyapunov’s direct method, or conditional Lyapunov exponents are considered. In this paper Lyapunov’s direct method is employed to show the asymptotic stability within the simplest piecewise linear master–slave chaotic flow. Also, however, in this paper, primarily the master–slave synchronization properties of the simplest quadratic chaotic flow and Ueda chaotic system are examined directly by means of mathematical manipulation of their dynamics equations, where possible, as well as via numerical simulations. In order to achieve this, in conjunction, numerical simulations and theoretical analysis are made use of. In this way it is shown that the synchronization error of the two aforementioned chaotic master–slave systems can indeed be predicted for certain driving signals, without the need for either analytical or numerical evaluation of the conditional Lyapunov exponents or employment of Lyapunov’s direct method. Finally, a digital communication system based on the initial condition modulation of the chaotic carrier by the binary message to be transmitted, in the presence of noise, is proposed and evaluated for the three chaotic systems investigated.

Analysis of flexible structures with occasionally rigid parts under transient loading

In the computation of solid structures under long duration transient loading it is often advisable to treat parts of the structure at least for some time of the analysis as rigid bodies. Such a procedure increases first the efficiency of the analysis considerably and second the numerical condition of the system of equations benefits substantially within the numerical solution process. In particular structural modeling capabilities concerning boundary conditions and load transfer are considerably extended compared to a straightforward modeling with rigid bodies. The parts assumed rigid with small strains and sharing almost only a rigid body motion can be found in systems with high difference in stiffness as well as in systems with modestly loaded parts. A methodology based on the Energy Momentum Method is developed for creating occasionally rigid bodies within the computation. A criterion based on strain rates is used to decide for the modification from flexible to rigid. For optimal reduction of the number of degrees of freedom the rigid bodies are formulated using a transformation to minimal coordinates, also called master slave concept. The numerical examples involving long duration motion and large rotations demonstrate the possibilities of the developed procedure.

A robust load-sharing control scheme for parallel-connected multisystems

Parallel connection of inverters or converters is one useful method for solving the high power requirements. However, a load-sharing problem among parallel-connected systems is not an easy task, since crosstalk may take place among the subsystems. We develop a general methodology for solving the load sharing problem using the master-slave concept. In synthesizing the input to the slave system, we utilize system-dynamics-dependent filters. With the proposed method, we can equally distribute the load, or can give a certain offset (in load) to a specific subsystem. To show the usefulness of the proposed control scheme, we perform a simulation study with two practical systems: a current-balancing control in parallel-connected pulsewidth modulation converters and a speed and tension control for a bridle roll system in a steel mill.

Coordinative Control of Different Kind of Manipulators Using an Incremental Fuzzy Compensator

A coordinative motion control is described for two different kind of manipulators by using a master-slave concept. Here, the master part consists of a pantagraph-type two link manipulator driven by a torque command, whereas the slave part is an industrial manipulator driven by a position command with a force torque sensor. To achieve a desired contact force between the slave manipulator and an object, a compensative position command is generated by using an incremental fuzzy reasoning with the force sensor information. The effectiveness is verified by experiments.

Design of a data logger and instrument-mounting platform for seabed sediment-transport research

A microprocessor-based data logger and an instrument-mounting platform used in shelf sediment-transport and boundary-layer research are described. The data logger is based on a master-slave concept and can support, in principle, any number of sensors, which all operate on the same real-time base. Considerable flexibility in experimental design results, which enables the optimum use of data-storage capacity and power supplies, as well as the implementation of complex sampling schemes. The instrument-mounting platform provides the physical support for current meters and optical and acoustic devices for measuring suspended-sediment concentration. The guiding design principle has been that the structure should disturb the flow only in ways that do not compromise the application of typical methods of data analysis.

A universal power supply integrated circuit for TV and monitor applications

A switching mode power supply circuit which operates according to the master-slave concept and is located in the primary side of a TV set or monitor offline flyback power supply is described. The circuit ensures the starting function, the standby function according to the primary regulation principle, and the normal operating mode in association with a switching regulator located in the secondary side of the power supply. The circuit provides the base drive of the power switch without external boosters. It ensures various safety functions, such as power transistor current limitation and under- or overvoltage detection. Although mainly designed for the master-slave concept, the circuit can also be used alone, according to the primary regulation concept, or in association with an optocoupler. The circuit layout is presented. >