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Master's
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Fast growth of computing potential of PC's allows using them for simulation processes succesfully, that exist in electrical circuits. It makes possible to do great part of diagnosting while developing radioelectrical device, and dont making real model. There are some programs, that allow to do that: ELECTRONIC WORKBENCH, MULTISIM, MICROCAP, OrCad, PCAD. They succesfully complete many of practical tasks by computing electrical circuits for high frequences. Today all of them complex programs of through projecting, that allow develop analog-digital circuits from the idea till making it on a plate. Their subsystem based on using input language of program Pspice. It was developed by corporation MicroSim in the early 70th. Hystorically it was the first and because of simplisity input language and reliability of using algorythm became standart for all such programs. Today versions of programs have developed graphical interface, that allows to write the task for modelling on language of electrical circuits. In the most cases it is more convinient, than using text input language of programm Pspice [1].
At the given stage of development of a science there is a set of programs for testing of digital devices, but all is differently with diagnostics of analog devices. Programs tests in which are written manually, don't possess sufficient flexibility and the universality necessary for diagnostics of malfunctions of devices. Functionality of the program depends on the expert-diagnostician making the test for this or that model of the device. An overall objective given магистерской works is working out of a method of modeling of malfunctions with which help will probably diagnose a wide range of analog devices, for the subsequent elimination of the found out defects. This direction is actual in connection with its novelty and insufficient experience of diagnosing in the given branch.
Scientific importance of workВIn given masters work I will develope a new method and structures of modeling of analog malfunctions, on the basis of Pspice-model of object of diagnostics.
Practical value of results of workOn the basis of the offered methods and structure will software of modeling of analog malfunctions which are developed can be used in system of diagnostics of analog devices.
Diagnostics of analog devices are devoted following masters works:
Similar researches across Ukraine aren't present.
In the world the following was engaged in similar researches:
In mine masters work the elementary analog devices, as the resistor, inductance, the condenser will be investigated. The problem is very labor-consuming as even to hold full testing of the scheme from one resistors will demand detailed study of set of details. It is necessary to set critical parameters for each element (rupture, short circuit), and also to check up on small deviations. For each of resistors ideally it is necessary to execute search of possible parameters, which in each separate case to transfer in system of modeling OrCad then to carry out the analysis of a target file with results. In a file it will be specified, on how many has occurred or there was no deviation in the scheme to the set parameters.
The System should carry out check of any analog device, thus on an input it would be possible to choose any of the offered signals (a sinusoid, a saw, noise), and on a scheme exit to connect the analyzer. But as the problem turns out very volume will enough realize simple analog elements for taken away for masters works term.
The program cover for management of internal language OrCad – PSpice on which modeling of all studied devices will be made should be as a result received.
The Structure of work of a program complex is presented on fig. 1.
ДFor each of scheme elements the structure of a following format will be described:
<имя элемента> <узлы подключения> <параметры элемента>
Примеры описания пассивных элементов[4]:
* Сопротивление Rmain номиналом 60 Ом
* подключено между узлами 2 и A1:
Rmain 2 A1 60
The Developed program module should carry out search of probably admissible parameters of elements then to transfer this data to processing in OrCad. The modeling system compares the set scheme with reference and results of work of schemes submits on the comparator. The comparator gives out 0 (in case of identity of work), or 1 (in case of failure detection). As at modeling the constant target signal, and changing in time can turn out not, it is necessary to transmit a target signal of the reference scheme for comparison of results after the comparator. Thus to define in a percentage parity a deviation of a signal of the comparator and the reference scheme, and at a deviation preset value to reveal malfunction.
The Investigated scheme should comprise deviations of values of parameters in the ranges set by the user, for revealing of malfunctions. In a case if the target data differs within admissible a deviation the scheme doesn't contain malfunctions in itself. We will result 1 more more a bright example entrance (fig. 2) and the day off (fig. 3) files.
Three sizes are of interest in a target file: potential of knot 2, the power supply current, disseminated capacity [4]. The program module planned for working out will analyze received results and to compare them with reference then schedules of changes of the diagnosed scheme concerning the reference will be constructed. From resulted before structure of a developed method of modeling 3 components will enter into the program module: modeling initial characteristics and schemes a part, the generator of malfunctions within admissible a range for the investigated scheme and the comparator. The part моделирущая characteristics will contain base reference parameters of elements and structure of the reference scheme. The generator of malfunctions will be to change on already created structure of the reference scheme values of parameters of elements in admissible ranges. Also it is planned to model critical malfunctions of the scheme, such as rupture and short circuit. The analog comparator should reveal all deviations in work of the investigated scheme and to reflect it in the target characteristic then the data it will be transferred in the basic program module for the further processing.
The new method of modeling of malfunctions of the analog devices, based on language Pspice should be as a result developed. The given method will allow to model except malfunctions of elements, critical malfunctions. Diagnostics will be spent by comparison of the investigated scheme with reference and upon termination of diagnosing to be deduced the graphic information on a correctness or an incorrectness of work of the analog device.
The important remark
At a writing of the given abstract магистерская work isn't finished yet. Definitive end: November, 2011 the Full text of work and materials on a theme can be received at the author or its supervisor of studies after the named date.