電阻溫度計的檢定-基礎附錄3

1、電阻溫度計的檢定電阻溫度計的檢定2一般的檢定步驟一般的檢定步驟Start New Record開始新的記錄Visual Inspection視覺檢查uClean?, bent?干凈？彎曲？Generic Checks普通檢查uInsulation resistance, Self-heating & Immersion assessmentsu絕緣電阻，自熱和浸入深度的估計Conditioning and Adjustment處理和調整uAnnealing & Stability tests退火和穩(wěn)定性測試Comparison比較uSPRTs and very best partially s

2、upported PRTs Fixed PointsuSPRT和非常好的部分支撐的PRT固定點uPrecision PRTs Comparison in bathsu精密PRT在恒溫槽中使用比較法uIndustrial PRTs Comparison in Dry-Wellsu工業(yè)PRT在干井爐中使用比較法Analysis分析uCalculation of coefficients or R vs. T table系數的計算或生成分度表Uncertainties不確定度uReference thermometer, heat source stability & uniformity, pro

3、be specific errorsu參考溫度計，熱源穩(wěn)定性和均勻性，探頭特有誤差Complete Records完整的記錄3Calibrating PRTs檢定檢定PRT Characterization標定uThermometer resistance is measured at several temperature points and the data is fitted to a mathematical formula (mathematical model).u在幾個點測量溫度計的電阻，通過這些數據得到數學公式（數學模型） Tolerance Testing誤差測試uTher

4、mometer resistance is measured at several temperature points and the data is compared to defined values at those temperatures. No fitting is performed.u在幾個點測量溫度計的電阻，數據與相應的溫度點的定義值比較。4Characterization or Tolerance Testing?標定或誤差測量標定或誤差測量 Characterization標定uMost common for precision PRTs, provides best

5、uncertaintyu對精密PRT是最常用的方法，具有最好的不確定度uResult is unique to probe, requires unique compensation or linearization in readout to take full advantage of calibration datau結果只對單獨的探頭，需要在測溫儀進行單獨的補償或線性化以充分利用檢定數據uRequire at least 5 data points and substantial mathematics for reasonable resultsu需要至少5個點的數據和數學計算以獲得

6、合理的結果 Tolerance Testing誤差測量uMost common for industrial grades of PRTs, only provides for standardized uncertaintyu對工業(yè)級PRT最常用的方法。只提供已經標準化的不確定度uResult classifies probe into an accuracy grade, allowing non-probe specific compensation to be usedu結果按準確度等級分類，允許使用補償uCan be completed with a few as 1 or 2 da

7、ta pointsu使用1或2個數據即可完成。5Example Configuration配置配置舉例舉例Precision Thermometer Readout / DMM Method精密測溫儀萬用表方法ReferenceProbeDigital MultimeterProbes Under Test6Example Data Set測試數據測試數據舉例舉例4個點水三相點個點水三相點溫度溫度測量值測量值7Calculate Coefficients using ITS-90 Deviation Functions使用使用ITS90溫標偏差函數計算系數溫標偏差函數計算系數Set of eq

8、uations 等式Solving for a and b using example data:求解方程a = -5.3581671E-04b = 2.0307049E-05 Wa Wb WTTT111211()() Wa Wb WTTT222211()() Wa Wb WTTT333211()() Wa Wb WTTT444211()()8Check Curve Fit Using ITS-90 Inverse Functions使用使用ITS90逆函數驗證逆函數驗證Calculate residuals usingITS-90 inverse functionsCalculatedTem

9、p (K)Actual Temp(K)Residuals(K)429.7494429.7490 0.0004595.0770595.0780-0.0010573.1509573.1500 0.0009692.6768692.6770-0.0002使用使用ITS90逆函數計算殘差逆函數計算殘差9Procedures - Tolerance Testing步驟誤差測量步驟誤差測量 Typical approach for medium to low accuracy and industrial applications 主要應用于中等或低準確度的工業(yè)應用 Resistance at temper

10、ature T is compared to defined (table) values 在溫度T時的電阻與分度表的值比較 Internationally DIN 43760, IEC-751, or ASTM 1137 standards and defined limits of error are common 國際上常用的DIN43760, IEC-751,或 ASTM 1137 標準10PRT分類誤差分類誤差11Example of Limits of error using IEC Tolerances使用使用IEC允差的例子允差的例子IEC 751 class AIEC 751

11、 A類= 0.13 + 0.0017|t|C 100 C = 0.13 + 0.0017|100| = 0.30 CIEC 751 class B IEC751 B類= 0.25 + 0.0042|t|C 100 C = 0.25 + 0.0042|100| = 0.67 C12工業(yè)允差測試的例子工業(yè)允差測試的例子 Basic system基本系統(tǒng)uFluke-744 Documenting Process Calibrator福祿克744校準器uHart Field Dry-Well哈特現場干井爐9103 for -25 to 140 (9103干井爐）9141 for 50 to 650

12、（9141干井爐）uHart 5614 Secondary Reference PRTu哈特5614二等標準溫度計 Approximate system uncertainty 0.34C (rss method)近似的系統(tǒng)不確定度0.34u744 PRT measurement accuracy 0.3Cu744測量PRT準確度為0.3Cu9141 combined stability and uniformity u9141的穩(wěn)定性及均勻性綜合指標u0.16 420Cu5614 PRT 0.023C13精密精密PRT的系統(tǒng)舉例的系統(tǒng)舉例 Basic System基本系統(tǒng)u1529 CHUB

13、-E4 Readout1529測溫儀u5626 Secondary SPRT5626二等標準uDeep Immersion Compact Bath深井臺式槽u9938 MET/TEMP II Software9938軟件 Approximate uncertainty 0.03C 近似不確定度0.03Cu1529 CHUB 0.012C 200Cu5626 SPRT 0.009C 420Cu6331 combined stability and uniformity u6331穩(wěn)定性和均勻性綜合指標u0.03C 300C14標準溫度計系統(tǒng)舉例標準溫度計系統(tǒng)舉例 Basic equipment

14、基本系統(tǒng)u1590 SuperThermometer超級電阻測溫儀u5681 Quartz SPRT石英護管一等標準溫度計u9114 Freeze-Point Furnace固定點爐u590X Fixed Point Cells固定點容器u9938 MET/TEMP II Software軟件 Approximate uncertainty 3mK to 5mK 近似不確定度3mK to 5mKu1590 1.5mKu5681 SPRT 1mKu5906 Zinc Point 1mK15Conclusion/結論結論 PRTs are truly remarkable instruments PRT是非常實用的儀器 With proper care and attention to detail the