This paper is concerned with the design procedures of an automated testing tool, developed in Matlab ® /Simulink ® environment, that performs software verification during runtime on a PLC (Programmable Logi...
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This paper is concerned with the design procedures of an automated testing tool, developed in Matlab ® /Simulink ® environment, that performs software verification during runtime on a PLC (Programmable Logic Controller) or so called HiL test (Hardware-in-the-Loop) for model-based development of control applications. In addition to checking the “semantic” or “functional” correctness of the automatically generated C++ - Code with RTW (Real Time Workshop ® ) for algorithms designed and developed in Simulink ® on hardware targets, the tool compares results obtained from the HiL test with the results of the MiL test (Model-in-the-Loop) performed in early stage of development for the same developed application. The main purpose behind this work is to develop reliable software that fulfil system requirements and to test its behaviour during realtime hardware simulation, in order to achieve the validation step which represents the terminating - step of almost all projects.
Data flow processing is a common task of embedded systems which is usually modeled as a pipeline. Errors in a block of this pipeline can be propagated through it thus leading to unexpected and erroneous behaviors. For...
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Data flow processing is a common task of embedded systems which is usually modeled as a pipeline. Errors in a block of this pipeline can be propagated through it thus leading to unexpected and erroneous behaviors. For safety related applications, this pipeline has to be able to identify and react to failures. The DMOSES model-driven development method uses deterministic UML activities to describe and implement data flow processing. This method ensures deterministic behavior of concurrent processing. Design by Contract defines formal, precise and verifiable interfaces for software components. We propose a development method for safe data flow processing based on the integration of this concept in deterministic UML activities. This integration allows the identification of errors by detection of contracts violation. This paper presents an extension of the DMOSES tool for contracts verification at the model level and their monitoring at runtime.
In chapter 2 the authors firstly give a short outline of Bayesian inference, Bayesian prior and posterior distributions and Bayesian estimators. In chapter 3 they investigate random variables following a Poisson distr...
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ISBN:
(纸本)9784883254194
In chapter 2 the authors firstly give a short outline of Bayesian inference, Bayesian prior and posterior distributions and Bayesian estimators. In chapter 3 they investigate random variables following a Poisson distribution. They then handle the rate parameter as a random variable, and show that the associated posterior distribution is an Erlang distribution. They then calculate the density functions of two ratios related to rate parameters. In chapter 4 the authors are dealing with partial stroke tests, proof tests, failure rates, and diagnostic coverage factors, determine the respective probability density functions and calculate confidence intervals. Finally they discuss the question whether or not to take account of the last failure of a test interval.
The development of embedded sensing applications based on integrated circuits leads to ever-growing complexity of VHDL-code and requires sophisticated testability to achieve high diagnostic coverage. The norm IEC 6150...
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Several standards and guidelines give advice on the development of qualitative and quantitative criteria to evaluate safety related systems, in order to apply these in safety critical applications. These standards don...
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ISBN:
(纸本)9784883254194
Several standards and guidelines give advice on the development of qualitative and quantitative criteria to evaluate safety related systems, in order to apply these in safety critical applications. These standards don't take into account the possibility of an external attack on the safety related system. In this paper, we will describe the current situation and explore methods and models for security and safety related systems with the help of Markov-models.
The standard IEC/EN 61508 defines the requirements for safety systems to be applied to industrial plant safety independently of the application. It is not only intended as a basis for the development of future applica...
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ISBN:
(纸本)9784883254194
The standard IEC/EN 61508 defines the requirements for safety systems to be applied to industrial plant safety independently of the application. It is not only intended as a basis for the development of future application orientated standards, but also as a basis of all safety related electrical, electronic and programmable electronic systems, in order to apply it to safety critical applications. The purpose of this paper is to describe the SILCas tool which enables the user to determine the Safety Integrity Level (SIL) and the probability of failure on demand (PFD) for entire SIFs (consisting of sensor, signal processing, actuator) and for different systemarchitectures.
This paper presents a new tuning method based on model parameters identified in closed-loop. For classical controllers such as PI(D) controllers a large number of simple tuning methods for various application areas ex...
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ISBN:
(纸本)9781849192521
This paper presents a new tuning method based on model parameters identified in closed-loop. For classical controllers such as PI(D) controllers a large number of simple tuning methods for various application areas exist. However, when it comes to designing a generalised predictive controller (GPC) four parameters have to be specified. To choose those parameters is not a trivial task since they are not directly related to control or regulation performance. The presented tuning method exploits model-parameters to select suitable controller parameters. Additionally, a Rhinehart filter is incorporated in the design to decrease the impact of noise, therefore, a fifth parameter has to be optimised. The proposed method has been tested in simulation and on a real system.
This paper presents the recent design and development aspects considered within a current project running at the department of computerarchitecture and systemprogramming. The project "Safety WLAN architectures ...
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ISBN:
(纸本)9784883254194
This paper presents the recent design and development aspects considered within a current project running at the department of computerarchitecture and systemprogramming. The project "Safety WLAN architectures for safety critical applications related to diagnostic and predictive maintenance possibilities" includes the aspects of diagnostic and predictive maintenance strategies as well as safety related hardware, reliable software design and reliable wireless communication. This paper considers design strategies for the development of reliable, safe sensor systems for process control.
This paper presents a new tuning method based on model parameters identified in closed-loop. For classical controllers such as PI(D) controllers a large number of simple tuning methods for various application areas ex...
This paper presents a new tuning method based on model parameters identified in closed-loop. For classical controllers such as PI(D) controllers a large number of simple tuning methods for various application areas exist. However, when it comes to designing a generalised predictive controller (GPC) four parameters have to be specified. To choose those parameters is not a trivial task since they are not directly related to control or regulation performance. The presented tuning method exploits model-parameters to select suitable controller parameters. Additionally, a Rhinehart filter is incorporated in the design to decrease the impact of noise, therefore, a fifth parameter has to be optimised. The proposed method has been tested in simulation and on a real system.
The calculation of "Probability of Failure on Demand" (PFH) according to IEC 61508 shows for a 1oo1 and a 1oo2 system using the same initial values that - as expected - a 1oo2 system is a better safety integ...
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The calculation of "Probability of Failure on Demand" (PFH) according to IEC 61508 shows for a 1oo1 and a 1oo2 system using the same initial values that - as expected - a 1oo2 system is a better safety integrity system than a 1oo1 system. This means, that a 1oo2 system has a lower probability of failure than a 1oo1 system. Comparing the same systems operating in a high demand or continuous mode of operation, there will be some cases, especially for systems with high diagnostics, where a 1oo1 system has a lower ¿Probability of Failure per Hour¿ (PFH) value than a 1oo2 system, using the PFH formulas according to IEC 61508. Using the equation according to IEC 61508, it is also possible that the PFH value is apparently better the longer the system runs either in the high mode or continuous mode of operation. Both results are irreproducible in industrial reality. Therefore, this paper will analyze first what conditions are necessary to get a hazard event when using a PFH system. Only those cases are considered in the modified PFH calculation, in which indeed a hazard event occurs. In a second step, it presents a new approach with the help of plausible arguments in order to calculate the PFH value of a PFH system considering a high diagnostic and a very low failure rate. The presented approach can also be correctly verified with mathematics using the advanced Markov model also described in this paper.
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