Fictitious instrument is fictitious the occurrence of the instrument is a revolution that measures instrument phylogeny to go up. The development of the new theory that develop as the height of microelectronics technology, computer technology, software technology, network technology and surveying the application that goes up with the instrument and test, new method, new field brought about a kind of new-style instrument -- fictitious instrument (the birth of Virtual Instrument) . It makes full use of newest computer technology will realize the function with patulous instrument; It is OK to use computer screen figure, conveniently imitate the adjusting control face plate of all sorts of instruments, with the form of all sorts of need expressive output detects result; Realize the analysis of major signal and processing with computer software, fulfil all sorts of adjusting control and test function. "Software is an instrument namely " , in fictitious instrument system, software is producing core effect, already had a kind of such fictitious instrument and its system, amid, hardware is to solve the input of signal to output only, and core function is finished with software, be based on fictitious instrument, the user can define the function of the instrument according to his need, adopt the method that software revises, very conveniently the function of system of instrument of change, increase and decrease and dimensions. Compare with traditional instrument photograph, if the advantage of fictitious instrument expresses 1 to show. But fictitious instrument also is not perfect, get easily when joining with other equipment the limitation of external environment and condition, undertake as a result of need much software is calculated additionally, the likelihood is caused bigger when delay, the need below this kind of circumstance uses traditional hardware instrument to replace. Fictitious instrument can be used at national defence, aerospace, nuclear physics, petro-chemical etc get region of <DIV Id=AdvertisemantBar1><DIV>cript>cript> </DIV></DIV> , at present development environment basically has two kinds: One kind is text language, if C, C++ , LabWindows /CVI is waited a moment; Another kind is graphical language, if the LabVIEW of NI company is mixed,the VEE of HP company is waited a moment. As a result of the convenient sex that graphical language develops, got the welcome of broad engineer, an engineer that does not have a lot of experience in computer language respect also can be inside shorter time the skill that masters fictitious instrument development, can use a project among practice. The fictitious instrument application in university lab construction has above as a result of fictitious instrument all sorts of advantages, of the fall that and handle case as computer hardware and signal waits for auxiliary equipment price and computational ability rise, fictitious instrument can have replaced equipment of test of major circuit electronics, the development that is fictitious lab thereby offerred a possibility. As campus net gain ground, fictitious lab can provide the network online experiment, saved the defray such as many lab, hardware, personnel on one hand, also can run experimental course effectively on the other hand. Fictitious instrument also can be used in all sorts of physics to mix other the domain related to signal observation and processing. The mechanical department of Stanford university of the United States asks 3, the data that 4 grade student uses fictitious instrument to have a test when the experiment is collected and the experiment is controlled. A few universities of domestic if university of university of Tsinghua university, Xi'an traffic university, China north electric power, southeast university, Fudan University, Shanghai traffic, and south the university of university, Hua Zhongke ability, Sichuan university successful relevant course that offerred fictitious instrument. Notable is, a few dimensions are lesser, conditional difficulty, the school of funds insecurity, also begin to introduce the lab that is based on fictitious instrument, solved the problem that experimental funds is in short supply greatly. Devise example: Circuit overshoots because come true to monitor and be answered in development process,Cheng monitors appearance too those who put a function is main accuse different, and the parameter of both need set also is different, so on whole face plate accuse more, to make instrument face plate clearer, more control easily, at the same time also to avoid a few needless operate by accident, mix the face plate that monitor so time put face plate to be placed apart. The face plate that monitor is shown 1 times like the graph, from the window that monitor can the data that observation goes to to be handled every time (acquiescent value is nodded for 500 data) undee, can conclude from observed amplitude size had gone out to overshoot whether Cheng happens, more intuitionistic of course method is to observe this window calls the police leftly indicator light. "Stop to monitor " switch is used at control to install unreasonable circumstance to fall in parameter, the hand is moved quit this instrument job, raw data shows amount of sampling of data of unsettled of the data presentation in casing, if this is occupied,basically be 0 very small perhaps number (quantitative class does not exceed 101) , state the job is regular, if this is worth,increase gradually and quantitative class exceeds 102, explain parameter setting is unreasonable, stop to monitor with respect to need. Can pass click " working status " pushbutton, undertake " monitor / time put " the switch of condition. Overshoot Cheng weaveform shows equipment stops to run moment to output a weaveform automatically in the instrument too, its data gross is equal to speed of the processing in parameter setting to multiply count in order to save data set. Can make can be controlled in cursor shift pull the condition that changes control to be opened to fall with cursor, procrastinate on cursor directly with the mouse use the position that changes cursor thereby. Pursue the window of setting of parameter of the face plate that monitor that 1 circuit overshoots Cheng monitors appearance too can be installed include passageway date, sampling size of rate, amortize, save data set of data set number, amortize number, call the police standard, transfer process. The acquiescent parameter that this instrument offers transfers with what measure level at observation Ms process, can revise according to effective demand. The primary technological process of the program is shown 2 times like the graph. Graph the working flow weaveform that 2 circuit overshoot Cheng monitors appearance too is collected and collect need to use more computer resource continuously, also need to use buffer, and while general in be collected continuously need is collecting data, logarithm is handled according to undertaking an analysis, in this appearance that monitor, the imitate that use LabVIEW offers inputs intermediate module AI Config, AI Start, AI Read, AI Clear will come true, if the graph is shown 3 times,collect the model of the program. Graph 3 circuit overshoot Cheng monitors appearance to collect sketch map continuously too the weaveform that actual and fictitious instrument gets is not ideal, the reason is very much, be not ideal like experimental power source, and experimental derivation is ideal, so both have not the place of be identical, accordingly we need to undertake follow-up data processing, basically have filter wave at present, plan to close and add a window 3 kinds of methods. Digital filter is used at change and eliminating the weaveform that does not need, main component is answered for FIR(finite pulse) with IIR(infinite pulse is answered) two kinds. Every kinds have again low, connect high, belt, take the kind such as block, every kinds of type has Batewoci, car to wait than Xue Fu again inferior model. Below good case, digital filter is to the belt of unit gain is connected, the area that cannot pass completely block, and from belt to the transition that takes block bandwidth is 0, below actual condition, cannot satisfy afore-mentioned requirements, especially from belt connect take block to always one transfers process. We try to use filter, of the circuit that use RC rank jump answer regard a test as the object, use offset is better except undee distortion effect instead the car is smaller than Xue Fu connect filter. Although use filter to conduce to the interference that removes harmonic, but because square wave is contained originally very tall odd second harmonic, so filter wave makes energy of this one part is lost necessarily, accordingly its are affected also with respect to deviate rank jump answer. With R=1KW, the RC circuit of C=1mF compares 0-1t, the time of 1t-2t undertakes comparative, namely from 0 to 0.
The time that 6321 stability are worth and 0.
6321 stability are worth 0.
The stability of 8647 is worth time, if express,2 are shown. <DIV Id=Content> can be begged by above data piece, the T average of the wave that do not have filter is 0.
0011s, the T average of wave having filter is 0.
0021s, both differ very big, after visible filter wave as a result of harmonic loss, so deviate accurate result, reason filter wave is unworkable in the development of law of this one party in this instrument. The purpose that the curve drafts to close is to find out a series of parameter, pass the imitate test result with these best parameter, main and wired sex plans to close in LabVIEW, the index plans to close, polynomial <DIV Id=AdvertisemantBar1><DIV>cript>cript> </DIV></DIV> plans to close, general multinomial plans to close, general linear plans to close, general Levenberg-Marquardt plans to close etc. Below actual condition, to rank jump answer, can plan to close with the index, but the index plans to add up to those who ask all data are same symbol, to 2 rank circuit is not applicable, to first-order circuit, because power supply is not good,wait for a reason, unwarrantable also, answer to square wave more unworkable. Adding a window is the mainest technique in digital signal processing, its main effect is the finite short alignment in alignment of intercept long signal. But handling first-order and 2 rank of circuit rank jump answer time, as a result of rank jump weaveform not ideal, the initial phase that brings about alone weaveform is very poor, because this defines the scope of intercept very hard also. Think to be being paid no attention to undeely, pass software to be solved very hard, ultimate test we improved weaveform effectively through hardware method. Use circuit overshoots Cheng monitors appearance to have a test too, major parameter can use acquiescent setting, namely passageway date: 0; Sampling frequency: 20000; Amortize size: 5000000; Treat rate: 500; Call the police standard: 0.
10; Overshoot Cheng produces a standard too: 0.
10; Save data set number: 6; Amortize data set counts: 1. Transfer in circuit if the other set parameter in process observation expresses 3 to show. Epilogue overshoots through passing to circuit Cheng monitors appearance to develop the introduction of example, the hard, software that we can discover fictitious instrument has development gender, modular, can repeat use reach the characteristic such as interchangeability. And fictitious instrument can join a general instrument conveniently module or change an instrument module, and need not buy a completely new system, those who be helpful for testing a system is patulous, the fare that such operation wants is very low. And in fictitious instrument on this efficient development platform, the student is OK him design and experiment, the creativity thinking that is helpful for training a student and project carry out ability. Handle case through general purpose computer and simple signal, complementary with a few hardware equipment, can build the fictitious instrument lab that can complete all sorts of circuit electron tests, can form a network through campus net then fictitious lab. In developing a process, the teacher that needs to have experience and classmate solve the problem in fictitious experiment. Of course, in the process that uses fictitious instrument test, bring about a student to lose contact with reality likely, understand inadequacy to true experimental establishment, to the job medium true instrument understands insufficient problem, accordingly we advocate the production that increases a student knows practice, and be in process of our fictitious instrument development, mix as far as possible actual instrument is corresponding, and take measurable fictitious instrument experiment and the kind that conventional test ties come to those who achieve student learning result optimize. </DIV> CNC Milling