量值传递中绝对测量与相对测量转化实例的数理分析(二)

Mathematical analysis for conversion between absolute measurement and relative measurement in quantity transmission(Ⅱ)

在测量系统存在不同水平非线性误差使用不同名义Rtp值的标准铂电阻温度计时,以假设的较理想条件下的参数代入测量模型,同样得到物理概念清晰、简单直观的数理表达式。从分析过程和结果可以看出:在测量系统存在不同水平非线性误差下,方法一的检定结果误差依然比方法二的检定结果误差大得多,尤其是检定Pt100型热电阻,使用Rtp名义值为100Ω的标准铂电阻温度计,采用方法二时仪器测量误差对检定结果的影响仍然保持比方法一时小两个量级的水平。最后讨论该例中用绝对测量法实现高准确的量值复现或传递必须具备的设备条件及相对测量法在量值传递中的优势。

When using standard platinum resistance thermometer of R, value with different names due to different horizontal non-linear errors in measurements system, simple and intuitive mathematical expression with clear physical conception can be obtained the same way by substituting the parameters under hypothetical ideal conditions into measurement model. The analysis process and results show that： the determination error in the results of method I is still much larger than that of method II under the condition that different horizontal non-linear errors are in measurements system, especially the determination of PtlO0 thermal resistance. When using standard platinum resistance thermometer with Rtp nominal value being 100Ω under method Ⅱ, the influence of instrument measurement error on determination results is still about two levels lower than that of method I. Finally, equipment that must be provided to achieve highly-accurate quantity repetition or transmission via absolute measurement method and the advantages of relative measurement method in quantity transmission in the case were discussed.