Error Description and Modification of Virtual Measuring Instrument

When measuring, virtual instruments are inevitable to cause error damaging the precision of measuring resuits. It presents error constitution, methods of error transfer and synthesis of virtual measuring instrument. Based on the analysis of error transfer and synthesis of virtual measuring tual measuring instrument and gets the method of dealing instrument, it generalizes the error constitution formula of virwith errors. Then, errors can be modifyed.     

Digit Weight and Development of a Virtual Noise Analyzer

Traditional noise octave analyzers consist of filter network and weight network based on hardware. In order to realize a noise octave analysis by software, a digit weight method based on FFT is proposed. Using the method, digit weight and digit system error modification for virtual noise octave analyzer can be realized. Because of digit weight and digit system error modification, precision and stability of the instrument can be improved greatly. As an application, which combines the method of digit weight with the technique of digit system error modification, a low cost and high precision virtual real time noise octave analyzer is developed.     

基于LabVIEW的潜油电泵数据采集系统

应用LabVIEW虚拟仪器现场可编程门阵列(FPGA)对潜油电泵的电压、电流参量进行实时数据采集,通过上位机对采样数据进行分析处理,得到潜油电泵的视在功率、有功功率、无功功率和功率因数,并与电能质量检测仪检测数据进行对照。系统硬件采用NI sbRIO-9606和NI9683夹层板配合使用,突破了传统的依靠DAQ助手的硬件采集,基于现场可编程门阵列(FPGA)的数据采集系统,由软件构成采集功能芯片,可控性强,准确性高,应用性好。实验表明,该系统在误差允许范围内能够对数据进行准确采集。     

The Development of Dynamic Measuring Instrument for Checking Lead Errors of Ball Screws of Steering Mechanism

A new type of measuring instrument which is used to measure lead errors of ballscrews has been developed. The principle of the inStrument,the system strucrure,the computer inter-face. The analyses of the instrument error and the experimental results are presented, The principleof comparing synchronous displacement is used to achieve absolute measurement. The errors correc-tion technique is adopted to correct the errors of the instrument so that the high measuring accuracycan be botained.     

Design of Virtual Instrument for Automobile Based on PC/104

The design of virtual instrument for automobile based on PC/104 has been presented by comparing with the traditional auto meter. The paper focuses on the development environment, system construction and operation principle. The data of the virtual instrument is transported by CAN bus, and this system can monitor in real-time, display in digit and fire the alarm to the super-speed, save the record.     

Design and Implement of Site for Virtual Instrument Stream

With the abundance and development ,the transmission of virtual instrument on Internet become the exigent need in the field of instrument .The paper summarizes the building method of running flat to the stream of virtual instrument .The authors can complete remote test,exchange the testing data,so much as establish a dynamic league for test mission through the flat . For this flat ,they bring forward own opinion of systemic framework and running environment as well as local area network building . Furthermore, the anthors set forth the realization of function of accessing to database of virtual instrument.,the layout of site homepage. Finally,they introduce how to configure the site server ,what operating system to be selected for the site server and how to deploy the whole site .     

Design of Data Acquisition System for Vehicle Based on CAN Bus

To the question that a meter is correspond with a set of lead and a sensor,this paper presents a design of data acquisition system for vehicle based on CAN bus.In this way,the combinatorial instrument is only connected by a bus unit.Author introduces the data acquisition structure chart and the CAN interface,analyzes the software by program flow chart,and shows it's application for vehicle virtual instrument.A method of calculating vehicle speed,engine rotate speed and the course of development mileage are also given.     

Research and Development of the Network Virtual Instrument

This paper introduces a basic concept of network virtual instrument and presents a solving scheme based on the .net framework for web network virtual instrument in which the component technology are used to construct UI component, data-service component, signal-processing component, DB-component, controlling component and data-acquiring component, in accordance to demand these component above can be flexibly put on the right place to realize remote test and control. In the light of the scheme, a set of network oscilloscope based on web is designed to remotely sampling data, and the technology of data base is successfully used to administer the saving and taking of signals in network virtual instrument .     

ECG Information Management System of Virtual ECG Instrument

ECG is an important method in clinical heart disease diagnosis. The storing of lots of ECG and other corresponding materials in information management system has great value to medical researcher for their reference and research. Embedding the ECG information management system to virtual ECG instrument is not only enhanced the operating value but also increased the functions to virtual ECG instrument. The model of relation database and ActiveX Data Object (ADO) of VC++6.0 is used in the system. The key functions of Storing,Query,Deleting and core modules are introduced.     

Parameter Design for Machining Quenched Internal Helical Gears by EDM

Aiming at the problem of machining quenched internal helical gears, a method and its equipment are discussed and designed, which is used for machining quenched internal helical gears by EDM. Its characteristic and principle are proposed. The modifying design of the electrode gear and the calculating method of its modification coefficients is presented. Analyzing for the error of the machining equipment is done. The results show that this problem can be solved by EDM, the electrode gear is the modification gear of machined gear and the machining accuracy can be improved by controlling errors.     

Effect of Tooth Modification on Double Enveloping Worm Gearing

A method of modifying the double enveloping worm gearing with developable tooth surface has been proposed to reduce the sensibility of the worm gearing to the manufacturing errors. The tooth contact and kinematic precision of the modified worm gearing with manufacturing errors has been investigated by the TCA method. The results show that by the modification, the edge contact resulting from the manufacturing errors is avoided or effectively relieved,and the kinematic error of the worm gearing is obviously reduced.     

Virtual Sound Intensity Analyzer

The Virtual Sound Intensity Analyzer is a new instrument which has more advantages than the traditional Sound Analyzer. This Analyzer is based on fast Fourie transformation and virtual instrument technique.As an application, combining software and hardware, all kinds of weight noise sound level measurement and real-time noise octave analyzes realized synchronously. The design method has been introduced from three ways, which includes hardware, software and panel. An applied example and error analyze of Virtual Sound Intensity Analyzer are given.This Analyzer is low cost, small volume. and it is also easy to operate. It can be widely used in actual applications.     

Great Capacity of Data Logger Based on Virtual Instrument Technology

The Data Logger is an important secondary-instrument,which can be applied to automatic monitor and control system,and high speed local data acquisition for later analysis.The Virtual Great Capacity of Data Logger based on virtual instrument technology is a new instrument which has more advantages than the traditional Data Logger.The design method has been introduced from three ways,which includes system principle, hardware configuration and programming design, and an application example is given.This Data Logger is low cost,easy to take,also easy to operate.It can be widely used in many of actual applications.     

Modular Developing of Intelligent Controls-oriented Virtual Instrumentt

The concepts and principles of intelligent virtual controls(IVC) and virtual instruments based on them are introduced.The quintuple systematic model based on computer is discussed.By deep researching into the intelligent controls-oriented virtual instrument(ICVI) and its development system,the quintuple systematic model based on computer is introduced into ICVI systems,the uniform model of ICVI is built up and dissertated it in detail.The model builds uniform rules and methods for developing and using ICVI,and normalizes the development of ICVI.     

Analysis on the Effect of Harmonic on the Instruments with Average Value Principle

The application of non-linear load produces a mass of harmonics. The AC voltage meter and the AC current meter used in power system are usually rectifying instruments, which adopt principle of responding to the average value of voltage and current and get the virtual value by using of the proportion between the average value and it. Because they are designed based on the 50 Hz standard sinuous wave, the principle error will occur when the voltageof power system and the current of loads include harmonic. Based on their working principle, this kind of error is analyzed quantificationally. And the result shows that it can not be neglected. The voltage and current meters with real virtual value are proposed.     

Applying of the DSP Technology in the Virtual Instrument System

The hardware architecture and instruction set of the digital signal processor leads to its high speed and precision in processing data. Aiming at the virtual instrument's deficiency in speed and precision resulting from the limit of the computers' development, the author brings forward a method to promote the performance of the virtual instruments using the DSP technology. Implementing the complex algorithms in DSP and using the principal and subordinate DSP structure or DMA technology in the data acquisition card of the virtual instrument can promote the virtual instrument's real-time characteristic greatly. Several key technologies are introduced in realizing the data acquisition and processing card. The experiment shows that the digital signal processors have higher speed and precision than the computers when implementing complex algorithms, and that using the DSP to implement the algorithms is an effective method to promote the virtual instrument's performance.     

Development of Virtual Sweep Signal Source

A new kind of virtual sweep signal source which can be used to output specific sweep signal according to(users') configuration and can be widely applied to frequency characteristics measurement in the field of mechanics,electrics and electronics,is developed by using Dot Net software engineering technique,C/S architecture and general data acquisition platform.The virtual instruments not only make up the intrinsic defect of traditional instruments based on hardware components in high performance,remote control and data processing,but also indicate the powerful life and nice future of virtual instrument technologies.     

The application of grey residual error GM(11)model based on Markvo to aging behavior prediction of plastic

To solve the problem of poor prediction accuracy of GM(11)model when the data are discretebased on the sign of residual error modification value of prediction value being determined by Markvo chaina residual error modification is presented.The grey residual error GM(11)model based on Markvo is constructed through the modification of simulation value and prediction value obtained from GM(11)model.The prediction of tensile strength of LDPE greenhouse film under natural aging condition is taken as an exampleand the applicability of constructed model in the prediction of plastic aging behavior is researched.The results show that the relative error between prediction value and the actual value of tensile strength of LDPE greenhouse film after aging 18 and 21 months obtained from constructed model are 1.49% and 4.96% respectively.Prediction accuracy are higher than that(relative error are 3.40% and 6.75% respectively)obtained from GM(11)model obviously.Grey residual error GM(11)model based on Markvo needs less original data and has high prediction accuracythus it is a simple and reliable method for plastic aging behavior prediction.     

Application on Extracting Feature in State Monitoring and Fault Diagnosis

With the development and application of information and internet and virtual instrument technology ,the virtual globular company based on internet arises .To study remote state monitoring, remote fault detection and diagnosis about large scale, complicated and integrative equipment become very important. In the whole fault diagnosis system , the detecting ,data acquisition is original ,processing; transform and extracting features with the signal detected is a key factor. The theories and methods used in mechanical fault diagnosis is stated. The application of signal process and its feature extracting methods is introduced which are time domain, frequency domain and time frequency domain analysis, in state monitoring and fault diagnosis with its signal analysis. The processing method of random time variant special signal is given also.