直流电压表测量结果的不确定度评定

本文阐述了依据：JJF1059-1999《测量不确定度评定与表示》,在采直流标准电压源对直流数字电压表进行校准时的测量结果的不确定度评定的方法。     

一种校准直流低电阻表的方法

介绍了利用直流标准电压源和电流表来模拟微小电阻值,从而实现直流低电阻表校准的方法,并进行了测量不确定度评定和验证测试.     

直流毫伏级小电压校准方法

从直流毫伏级小电压校准方法研究的目的出发,对如何利用现有设备开展直流小电压测量仪器的校准作了详细描述。经过大量的试验、长期稳定性考核及测量不确定度的分析,证明用此方法校准直流小电压是可行的,解决了直流小电压测量仪器无法溯源的问题,并已用于实际工作中。     

基于改进型两次平衡对检法的感应分压器自校准方法

介绍了参考电势变压器和指零仪变压器设计原理,分析了屏蔽间泄漏对测量结果的影响;对常规两次平衡参考电势对检法进行了改进,使零平衡和段平衡测量过程中,参考电势和测差电路均可实现等电位保护;对自校准方法进行了推导,校准结果仅与段平衡和零平衡时锁相放大器测量的电压差值相关,与参考电势变压器、指零仪变压器、辅助变压器等的误差无关,屏蔽间泄漏的影响也得到消除。对1kV感应分压器进行了校准实验,并对校准结果进行了测量不确定度分析,其相对扩展不确定度的评估结果为5.4×10^-8(k=2)。     

直流标准功率源校准方法的研究

本文介绍了直流标准功率源的组成,讨论了直流标准功率源的校准方法并给出了不确定度的评定.     

基于Python语言的数字万用表自动校准系统的研究

本文开发了一种基于Python的数字万用表自动校准系统,由FLUKE5500作为标准器校准带有通讯接口的数字万用表,实现了直流电压、交流电压、直流电流、交流电流、直流电阻、交流频率的自动测量及测量不确定度计算,被校准数字万用表以安捷伦34410A为例.     

恒流脉冲点火电源校准方法研究

文章对恒流脉冲点火电源的工作原理进行了简单介绍,对其输出脉冲电流校准存在的问题进行了分析.提出了一种采用标准电压源比对的校准方法,并对使用直接法和标准电压源法时的不确定度分别进行了评定.使用标准电压源法校准时的不确定度比直接法缩小3倍,极大地提高了对恒流脉冲点火电源的校准能力,满足量值传递要求.     

高精度多功能校准源5720A交流电压的校准及分析

本文介绍了对高精度多功能校准源5720A交流电压功能进行检定、校准所需要的标准设备和校准方法,并给出采用上述校准方法对校准结果产生影响的不确定度分析及不确定度分量的合成。     

1000V多盘感应分压器标准建立

中国计量科学研究院研制了一台1000V多盘感应分压器标准装置,用作工频1000V电压比例标准。该装置使用了一种基于互感器注入的误差补偿技术,可准确提供从1×10^-8到1的宽范围比例出。感应分压器的误差校验使用了包含三同轴屏蔽技术的改进型参考电势增量法,并设计了多比例参考互感器以便对感应分压器进行整体校验。所研制的感应分压器准确度优于1×10^-7,校准结果不确定度小于2×10^-8。     

对直流电阻分压箱校准方法的探讨

本文用电压比法对0.005级直流电阻分压箱进行测量不确定度分析,并认为可以用此方法开展直流电阻分压箱校准。     

A low-voltage and high-frequency ac-dc transfer system usinginductive dividers

A setup for the calibration of high-input-resistance ac-measuring instruments for low voltages (mV) and high frequencies (1 MHz) is presented. The low voltages generated down to one hundredth of an ac standard voltage (0.5 V to 2 V) are traced by means of a one-decade inductive voltage divider (IVD) cascaded by a sub-IVD with a fixed ratio of 10-to-1. Construction details of the main IVD which are necessary to meet the requirements are given. The error characteristics are mainly determined by capacitive currents acting on stray and mutual inductances. The internally built-in resistive dc voltage divider and a special switch allow calibrations to be performed via effective ac-dc transfer at the standard voltage level. The first results for the calibration of a transfer standard, Fluke 792A, at 100 mV and 200 mV were in good agreement with results obtained with very sensitive multijunction thermal converters. Using such converters as standards in the new system will enable ac calibrations down to voltages below 1 mV     

An intercomparison of AC voltage using a digitally synthesizedsource

An AC voltage intercomparison was conducted by the National Institute of Standards and Technology (NIST) to determine the consistency of AC voltage measurements made at various standards laboratories. The transport standard used for this purpose was an NIST-developed, digitally synthesized sinusoidal voltage source whose RMS (root mean square) value was calculated by measuring the DC level of each of the steps used to synthesize the sine wave. The uncertainty of the calculated voltage at approximately 7 V RMS is typically within ±10 parts per million (p.p.m.) from 15 Hz to 7.8 kHz. This approach incorporates a technique of determining AC voltage with reference to a measured standard DC voltage, which is independent of the traditional thermal voltage converter approach. Preliminary measurements made at each of the participating laboratories agree with the calculated value to within ±20 p.p.m. These results indicate that at 7 V, in the low audio-frequency range, the AC voltage measurement techniques implemented at these laboratories are near the state of the art     

交流电压源毫伏级量值准确测量的技术研究

基于电压比例和交直流转换技术,提出了一种对交流电压源的毫伏级量值进行准确测量的方法。采用自行研制的二进制级联结构电压比例装置和792A交直流转换标准,将被测交流电压源的毫伏级量值溯源至交流电压国家基准。实验采用替代测量法,通过选用不同电压比例和不同792A量程的组合,在55Hz~5kHz频率范围内,对1台5720A多功能校准源10~200mV范围的交流电压进行准确测量。结果表明,各毫伏级交流电压示值相对误差的绝对值均不超过±40μV/V,测量结果扩展不确定度优于80μV/V,满足交流电压源毫伏级量值溯源需求。     

A learning algorithm for self-calibration of a voltage calibrator

An algorithm either to extend the calibration period or to reduce the measurement uncertainty of a DC voltage reference module is presented. This module is used either as a transfer, independent, or working standard, or as a reference module incorporated into a larger measuring system. The basic idea is that the deviation history of measured voltage differences of reference elements of a group reference module during the calibration period can be used as a learning period for a neural network. This neural network, when created, can numerically correct particular reference elements later in the working period. Results were obtained by simulation and evaluated on the basis of empirical data and simulated input functions. Hardware solutions to model this algorithm are discussed     

Automation and Evaluation of Two Different Techniques to Calibrate Precision Calibrators for Low Frequency Voltage Using Thermal Devices

Low frequency (LF) voltage and current are important parameters in electrical metrology. The standards for LF voltage and current are established by assigning AC–DC transfer difference to thermal devices, i.e. thermal converters or thermal transfer standard along with current shunts. Automated calibration systems have been developed based on Null method and measurement technique developed by Budovsky for calibration of precision calibrator in LF voltage and current against thermal devices. The technique based on the Algorithm developed by Dr. Ilya Budovsky (National Metrology Institute (NMI), Australia) has been compared with the conventional null technique. Indigenously developed software has been used to calibrate the precision calibrator in the entire LF voltage and current range using Holt thermal converters and current shunts. Calibration results at 1 V, 10 V in the frequency range from 10 Hz to 1 MHz as well as calibration results of 1 A in the frequency range from 40 Hz to 10 kHz are presented in this paper. These result shows that the measurement technique developed by Budovsky has reduced the complexity of AC–DC transfer measurements, measurement time and the uncertainty in measurement.     

NBS Provides Voltage Calibration Service in 0.1-10-Hz Range Using AC Voltmeter/Calibrator

Prompted by the need to support vibration and pressure measurements at frequencies down to 0.5 Hz (with expected future needs to 0.1 Hz), NBS now offers a calibration service for voltage standards and rms voltmeters in the range of 0.1-10 Hz. The means for the service is an "ac Voltmeter/Calibrator," an NBS-developed instrument containing an rms digital voltmeter and ac and dc voltage calibrators. The methods used to calibrate the ac voltage calibrator are discussed; also, application of the ac Voltmeter/Calibrator to the calibration of customers' voltage and voltmeter standards is described. Finally, a multifrequency voltage reference source with frequency-independent amplitude is proposed as a more suitable transfer standard than thermal voltage converters (TVC's) for the 0.1-10-Hz range.     

A new automatic system for calibrating the solid state DC voltage reference standards at NIS,Egypt

A new automatic system for calibrating the solid state DC voltage reference standards (Zener Diode reference standards) has been established at National Institute for Standards (NIS), Egypt to disseminate the unit of volt in the country. Besides, this system has been implemented as a coherent structure that, from the national DC voltage reference standards, can disseminate the traceability of all the instruments under calibration. The system consists of a set of programmable instruments and proper software. The software of the system has been built using the Laboratory Virtual Instrument Engineering Workbench (LabVIEW) graphical language. The system hardware is configurable by the operator on the basis of the specific calibration to be performed and it allows large number and different models of Zener diodes to be act either as reference units or as units under calibration. The design and the implementation of the system software have been discussed in details. Furthermore, the system validation has been carried out for the measurement repeatability and the results compatibility in both automatic and manual modes.     

Optimized Reproduction,Collection, Transmission,Processing, and Display of Measurement Data Obtained Using the National Standard of Voltage Unit – Volt

Measurement Techniques - Issues associated with automating the calibration of standard DC voltage measuring instruments are considered. An automatic calibration system is developed, studied, and...     

红外辐射温度计专用数字表的研制及评价

日本CHINO公司生产的IR-RST系列标准辐射温度计由于没有设计温度显示装置,无法实时显示温度,针对此类型温度计设计了一款专用的电压测量和温度显示,同时可提供24V直流电压的电测显示仪表。利用高等级的电压源和数字电压表,修正了本专用数字表的误差系数,并考核了稳定性,得到其最大相对误差不超过0.03%。与一款名义波长为0.65 μm的IR-RST辐射温度计配合使用,通过TG HT-9500型高温炉对其组合进行内插分度,实验结果证实分度后校准准确度优于0.03%,1 300 ℃时系统测量结果的扩展不确定度为0.62 ℃。