Validation of Calculations in a Digital Thermometer Firmware

State-of-the-art digital thermometers are arguably remarkable measurement instruments, measuring outputs from resistance thermometers and/or thermocouples. Not only that they can readily achieve measuring accuracies in the parts-per-million range, but they also incorporate sophisticated algorithms for the transformation calculation of the measured resistance or voltage to temperature. These algorithms often include high-order polynomials, exponentials and logarithms, and must be performed using both standard coefficients and particular calibration coefficients. The numerical accuracy of these calculations and the associated uncertainty component must be much better than the accuracy of the raw measurement in order to be negligible in the total measurement uncertainty. In order for the end-user to gain confidence in these calculations as well as to conform to formal requirements of ISO/IEC 17025 and other standards, a way of validation of these numerical procedures performed in the firmware of the instrument is required. A software architecture which allows a simple validation of internal measuring instrument calculations is suggested. The digital thermometer should be able to expose all its internal calculation functions to the communication interface, so the end-user can compare the results of the internal measuring instrument calculation with reference results. The method can be regarded as a variation of the black-box software validation. Validation results on a thermometer prototype with implemented validation ability show that the calculation error of basic arithmetic operations is within the expected rounding error. For conversion functions, the calculation error is at least ten times smaller than the thermometer effective resolution for the particular probe type.     

A digital signal-processing instrument for impedance measurement

A digital signal processing (DSP)-based instrument for impedance measurement is proposed. It implements two measurement techniques: the first technique allows the tracking of a time varying impedance to be carried out, and the second assures that good accuracy is obtained in reasonable measurement times. Both the software and the hardware of a prototype model are described in detail. The measurement rates and accuracy are evaluated and compared with those obtained using a reference Digibridge for a wide range of impedance values     

自动标准压力发生器控制原理及检定方法研究

自动标准压力发生器以其准确度等级高、操作简单、可自动检定等优点被计量检定部门作为计量标准器使用,与数字压力计的主要区别是其具有控制功能.本文通过介绍自动标准压力发生器控制功能的工作原理提出了能够提高控制功能的方法,结合检定软件和检定数据进一步诠释检定规程的要求,对更好地开展检定工作具有一定的参考价值.     

一种新型智能真空测量仪的研制

本文叙述的是以 DL- 5电离真空规为传感器 ,用单片机作控制和测量的一种新型智能真空测量仪。文中简述其工作原理 ,详叙实现它的方法。该仪与别的智能真空测量仪不同的方法是 ,采用单片机控制发射电流 ,这样不仅提高了测量精度 ,而且将发射电流参入计算 ,扩展了量程范围。该仪采用了软件抗干扰措施 ,有自诊和自保护功能     

基于普通PC机和智能仪表的远程数据采集系统

介绍了以普通PC机和智能仪表为基础研制开发的一种低成本计量数据采集系统，详细阐述了数据采集的过程、系统的构成、功能和特点。     

A Methodology to Test Instrument Software: An Automotive Diagnostic System Application

This paper aims to describe a new methodology specifically designed for testing measurement and diagnostic software. A black-box procedure allows the user to verify whether the functional requirements of a software module under test are fulfilled. The robust experimental design techniques and statistical theories implemented to generate the software input test sets are described in detail. The reliability of the testing methodology is estimated by applying it to diagnostic software in wide use throughout the automotive industry. The results of validation tests carried out on data from a car engine measurement system are reported and analyzed.      

虚拟仪器技术在1∶1摩擦试验平台中的应用

将虚拟仪器技术应用于现代测控系统，利用计算机的软、硬件资源代替传统测控仪器中大量的硬件，已经成为测控系统发展的一个重要方向。提出一种基于虚拟仪器技术的智能测控系统。该系统有效的运用于1：1摩擦试验平台，实现实时多通道数据采集、实时数据处理及显示、试验数据的后期分析处理、以及生成及打印试验报告等功能。     

高精度智能磁场测量仪的设计

设计了一种由微处理器控制的具有通信接口的高精度智能磁场测量仪,通过双只配对的集成霍尔传感器来获取磁感应强度的信号,采用压频变换器完成数据的采集,并对仪器进行了校准和实验．实验结果表明,所设计的磁场测量仪在整个量程范围内的测量精度达到了0.1mT．该仪器不但可进行磁场的精密测量,还可用于对无线通讯基站电磁辐射的网络化远程监测．     

海洋工程装备建造设备发展浅探

海洋工程装备向大型化、深水化发展,性能要求不断提高。海洋装备的建造面临着制造难度提升、环境更为复杂、关键设备精度要求高等难题,对创新加工装备、加工模式等提出了更高要求。制造设备需要在精细化、柔性化、加工与测量相结合等方面提升加工能力,同时在加工设备成套组织、加工控制软件等领域取得突破,从而为海洋工程装备产业的发展提供建造能力的支持,实现制造过程的精细化、智能化和绿色化发展。     

Application of a New Measuring Method to Large Size Measurement in an Automobile Panel

In view of the automobile panel's features of complex shapes,the higher requirements of appearance surface quality,and the more accurate mechanical model for CAE simulation etc,a kind of measurement method for large size measurement was presented.The method was composed of digital close-range industrial photogrammetry technology and computer binocular vision technology,it could measure workpieces quickly and precisely.First,XJTUDP software,which was a kind of photogrammetry software,figured out un-coded poi...     

An automated microcomputer systems for analyzing shaped-charge jet radiographs

A microcomputer-based system that can optimally digitize and process radiographic test information has been developed. This system allows the user to analyze radiographic experiments in a cost-effective manner made available with the recent technological advances in microcomputer digital image processing capabilities. This paper will examine the related hardware and software features of such a system developed to analyze shaped-charge jet radiographic tests. The system provides a quick inexpensive method of obtaining detailed information of shaped-charge tests. With the capability to analyze our tests in a repeatable accurate manner, we can now readily evaluate the performance of analytical design tools. Our results to date have been encouraging, showing good agreement between experiment and calculation.     

一种调制度测量仪的数字化精确评价与溯源方法

提出一种调制度测量仪校准方法,对低频载波情况,直接使用数字示波器进行采集测量,用软件无线电方式解调分析,获得调制域参数。对高频载波情况,首先用下变频技术将其转换成低频载波情况,然后进行测量、解调分析,并给出了详细过程。以此方式,将调制度测量仪的量值溯源到数字示波器的采样速率和幅度上,从而达到校准调制度测量仪的目的。在一种具体型号的仪器上所做的校准验证实验,验证了所述方法的有效性与可行性。     

温度测控系统在全自动包装机中的应用

温度测量与控制系统是全自动包装机不可缺少的温度测控部件,研究要求较高的控制精度和成本较低的测控模块,采用单片机作为数字控制器,并将温度仪表的分散控制转换为集中管理,即双路温度测量和控制于一体,实现真正意义上温度测量及控制的综合管理.克服了传统温度测控系统体积大、测控精度低、电路较复杂及测试困难、价格较高等问题.     

新一代霍尔效应智能磁强计的研究

智能磁强计是在设计上采用单片机和数字电位器，替代传统的机械电位器的基础上，研发出的一种基于霍尔效应的新型智能化磁场强度测量仪器。从根本上解决机械电位器因接触不良而产生的噪声、漂移等问题。实践证明：该仪器具有测量范围宽，测量精度高，校准常数调节和零点调节实现智能化，换能器更换方便和使用简单等特点，且具有较好的线性度＇其测量误差均在0.5％以内。已取得了较好的经济效益，应用推广前景广阔。     

On-line digital measurement for the quality analysis of powersystems under nonsinusoidal conditions

This paper presents a digital instrument for the power quality analysis in systems where voltage or current waveforms are nonsinusoidal. It is based on a C40 DSP and on a special high-speed data acquisition system. The analysis is performed by a recursive algorithm which allows the mutable system properties to be tracked on-line. The paper also goes on to discuss the performance of an instrument prototype, both in terms of accuracy and speed of measurement     

感应同步器宽度测量方法的研究

通过对传统的感应同步器位移测量方法的分析．提出了一种将软件与硬件有机结合的位移／数字转换新方法．利用该方法所研制的大位移传感装置、位移／数字转换装置与工业控制计算机配合．成功实现了对钢板宽度的测量与控制．     

A Statistical Approach for Improving the Performance of a Testing Methodology for Measurement Software

This paper describes the significant enhancements brought to an original methodology designed for testing measurement software. In a previous paper, the authors proposed a black-box seven-step procedure that allows the functional verification of complex instrument software to be performed. The main features of the procedure are concerned with the following: (1) the ability of reproducing actual correlations among the software inputs and (2) the need for a limited number of test cases. Making use of innovative statistical techniques, the methodology performance and reliability have been enhanced. Two further steps have been added with the aim of improving the correlation coefficient assessments and providing the estimations with a confidence level. Finally, a new strategy has been studied to optimize the number of test cases. The effects of the new solutions on the performance of the methodology are evaluated by applying the procedure to a complex software module employed in an automotive system. A comparison with the previous methodology version is also reported.     

A new low-cost voltage-to-voltage transducer for distorted signals

During the last years, measuring equipment has evolved toward the massive use of digital techniques and devices. The performance of analog-to-digital converters (ADC) and computing devices has constantly improved, and very accurate and flexible instruments can now be realized with bandwidths up to several kilohertz. Unfortunately, the transducers used to adapt the input signals to a suitable ADC input levels have not improved to the same extent so that the metrological characteristics of a DSP-based measuring instrument are mainly determined by the input transducers. Improving the performance of such transducers is thus of the utmost importance. This paper proposes a new voltage-to-voltage transducer, based on a capacitive divider and the Σ-Δ modulation techniques, that features a bandwidth wider than that of the traditional magnetic and capacitive voltage transformers. Specifications are provided on the transducer design, and the results of experimental tests on a lab prototype with primary voltage up to 500 V are reported     

Java-based distributed measurement systems

This paper focuses on the development of distributed measurement systems using Java and web tools. An approach is proposed which is based on object-oriented programming and client/server communications and which allows remote configuration and monitoring of a measurement system. The approach proves useful both for educational and industrial measurement requirements     

Instrument for Automatic Measurement of the Parameters of Solar Elements

An automated instrument for measurement of the parameters of solar elements based on an IBM personal computer, a digital potentiometer, and V7-21A digital voltmeters is described. The instrument produces a programmed specification of the load impedance of the solar elements in the range 0.002–800 , measurement of short-circuit currents up to 4 A, no-load voltages and the dark and light voltage-current characteristics as well as a calculation of the basic parameters of the solar elements with display of the results on a monitor and printer. The error of the measurements and of the calculation of the parameters of the solar elements is at most 0.4%.