The authors present their latest research results and developments of a code generator for Matlab/Simulink block diagrams and to download the generated code onto safety related systems such as a safety PLC (programmab...
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The authors present their latest research results and developments of a code generator for Matlab/Simulink block diagrams and to download the generated code onto safety related systems such as a safety PLC (programmable logic controller). An example demonstrates the different stages for code generation, evaluation and conversion before such code can be used in process industries. systematic approaches are necessary when such source code is embedded in process units. To the best knowledge of the authors, Matlab/Simulink source code has not been transferred on safety PLC before. Matlab/Simulink is an advanced and matured programming environment, especially for simulations of engineering processes and systems. Hardly no hardware exists, when it comes to download the developed algorithms and to use it in real world applications and so far this approach is the only one for using developed and tested Matlab/Simulink software on an safety related system.
This paper presents dynamic behaviors of autonomous solid oxide fuel cells (SOFC) with AC bus control. Both voltage and frequency control are utilized to achieve load-sharing of the studied SOFC feeding isolated loads...
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This paper presents dynamic behaviors of autonomous solid oxide fuel cells (SOFC) with AC bus control. Both voltage and frequency control are utilized to achieve load-sharing of the studied SOFC feeding isolated loads. A DC-to-DC converter is connected to the output terminals of the studied SOFC for stabilizing output voltage and current fluctuations under different loading conditions. The PWM inverter connected to the output terminals of the DC-to-DC converter is operated under voltage-controlled mode to regulate the voltage profile across the connected loads. It can be concluded from the simulation results that the proposed voltage and frequency droop controllers of the PWM inverter may operate satisfactory under stand-alone mode.
This paper is dealing with redundant optoelectronic data transmission with special respect to laser channels. The concept of the generalized erasure channel (GEC) is used to determine the probability of undetected err...
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This paper is dealing with redundant optoelectronic data transmission with special respect to laser channels. The concept of the generalized erasure channel (GEC) is used to determine the probability of undetected error for some binary symmetric and non-symmetric channels protected by appropriate codes. In detail, communication via different binary symmetric channels (BSCs), generalized erasure channels and symmetrized binary non symmetric channels (BNSCs) is investigated. Simple upper bounds are given, relating the new formulas to that one of the BSC Finally the results in connection with an inequality for proper codes are applied to multi wavelength optical transmission through channels generated by semiconductor lasers.
Safety-related systems mostly comprise hardware and software solutions. Due to the increasing application of complex hardware and software systems, the software systems have to be considered regarding safety as well a...
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The standard IEC/EN61508 provides the developer with guidelines to develop and implement safety related systems according to the international standard. The standard supplies qualitative and quantitative criteria to e...
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The Monte Carlo Simulation is one mean to calculate safety parameters like MTTF for safety related systems. This procedure helps simulating real failure on demand for safety functions using random numbers. The MTTF-va...
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The Monte Carlo Simulation is one mean to calculate safety parameters like MTTF for safety related systems. This procedure helps simulating real failure on demand for safety functions using random numbers. The MTTF-value can be calculated either directly, via Monte Carlo Simulation, using χ2 - or Student-distributions. Relevant is the fact, that a high number of simulation cycles and/or a large simulation time can be used.
Success of many modern applications is highly dependent on the correct functioning of complex computer based systems. In some cases, failures in these systems may cause serious consequences in terms of loss of human l...
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Success of many modern applications is highly dependent on the correct functioning of complex computer based systems. In some cases, failures in these systems may cause serious consequences in terms of loss of human life. systems in which failure could endanger human life are termed safety-critical. The SIS (safety instrumented system) should be designed to meet the required safety integrity level as defined in the safety requirement specification (safety requirement allocation). Moreover, the SIS design should be performed in a way that minimizes the potential for common mode or common cause failures (CCF). A CCF occurs when a single fault result in the corresponding failure of multiple components. Thus, CCFs can result in the SIS failing to function when there is a process demand. Consequently, CCFs have to be identified during the design process and the potential impact on the SIS functionality have to be understood. This paper gives details about the estimation and evaluation of common failures and assesses a loo2 system. It is a survey paper that presents the newest developments in common cause failure analysis.
Safety-related systems mostly comprise hardware and software solutions. Due to the increasing application of complex hardware and software systems, the software systems have to be considered regarding safety as well a...
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Safety-related systems mostly comprise hardware and software solutions. Due to the increasing application of complex hardware and software systems, the software systems have to be considered regarding safety as well as hardware systems. The development of a safety-related software system is similar to the development of a safety-related hardware systems. But there are still no generally accepted methods for developing safety-critical software. One has to use the methods, which fit best to the actual requirements. However, the calculation of reliability and availability for safety-related software systems is far more complex.
The probability of failure rate and error rate are important indicators for the assessment of applications for high-speed communication systems. The paper presents causes of faults and theoretical and practical method...
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The international standard IEC/61508 provides the developer with guidelines for the design and implementation of safety related systems according to this standard. This standard states qualitative and quantitative cri...
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ISBN:
(纸本)9781424435890
The international standard IEC/61508 provides the developer with guidelines for the design and implementation of safety related systems according to this standard. This standard states qualitative and quantitative criteria in order to judge a safety related system in such a way that safety critical applications can be implemented. This paper details a quantitative criterion which is the probability of failure on low demand, known as PFD. After an introduction into this topic, the principle steps to calculate the probability of failure with the help of reliability block diagrams for different hardware architecture will be detailed and presented. The PFD-equations will be derived for a 1oo1 architecture with the help of MacLaurin series.
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