REPORT ON AFRIMETS SUPPLEMENTARY COMPARISON: … · IPRT comparison (-50 °C to 450 °C)...

REPORT ON AFRIMETS SUPPLEMENTARY COMPARISON: PLATINUM RESISTANCE THERMOMETER AND DIGITAL THERMOMETER

CALIBRATIONS AGAINST ITS-90 OVER THE RANGE -50 °C TO 450 °C AFRIMETS.T-S1

Final report (16 August 2017) National Metrology Institute of South Africa

Private Bag X34, 0040 Lynnwood Ridge, South Africa

IPRT comparison (-50 °C to 450 °C)

AFRIMETS.T-S1 Final report (16 August 2017)

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CONTENTS LIST

1. INTRODUCTION .................................................................................................................................. 3

2. PARTICIPANTS .................................................................................................................................... 3

3. ARTEFACTS ........................................................................................................................................ 4

4. MEASUREMENT PROCEDURE .......................................................................................................... 4

5. MEASUREMENT DATA ....................................................................................................................... 4

6. CONCLUSIONS ................................................................................................................................. 31

7. REFERENCES ................................................................................................................................... 31

APPENDIX 1: PROTOCOL FOR AFRIMETS.T-S1 ........................................................................................ 32

APPENDIX 2: INSTRUMENTATION ............................................................................................................... 51

APPENDIX 3: UNCERTAINTY BUDGETS ..................................................................................................... 56



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1. INTRODUCTION

The Comité Consulatif de Thermometrie (CCT) has organised several key comparisons to compare

realisations of the ITS-90 in different national metrology institutes. To keep the organisation, time scale and

data processing of such a comparison manageable, the number of participants in a CCT Key Comparison

(CCT KC) is limited to a few laboratories in each major economic region. Subsequent regional key

comparisons are linked to the applicable CCT Key Comparisons by link laboratories.

For the temperature range from -189.3442 °C (triple point of Ar) to 660.323 °C (freezing point of Al), a key

comparison, CCT-K3, was carried out from 1997 to 2001 by representative laboratories in North America,

Europe and Asia. Following CCT-K3, the Asia-Pacific Metrology Program Key Comparison 3 (APMP.T-K3)

was organised for national metrology institutes in the Asia/Pacific region. NMIA (Australia) and KRISS (South

Korea) provided the link between CCT-K3 and APMP.T-K3. APMP.T-K3, which took place from February

2000 to June 2003, covered the temperature range from –38.8344 °C (triple point of Hg) to 419.527 °C

(freezing point of Zn), using a standard platinum resistance thermometer (SPRT) as the artefact [1]. NMISA

participated in APMP.T-K3 in July 2000, achieving differences from the CCT-K3 Average Reference Values

(ARVs) of ≤ 0.5 mK, with U (k = 2) of 0.5 mK to 1.2 mK. This allows NMISA to link other comparisons of PRT

calibrations to CCT-K3, the relevant global comparison.

The first AFRIMETS Supplementary Comparison of industrial PRT (IPRT) calibration capabilities,

AFRIMETS.T-S1, was proposed in the April 2002 report of pilot comparison SADC.T-P1 (liquid-in-glass

thermometers from 0 °C to 50 °C) and was carried out from March 2008 to October 2010. NMISA was the

pilot. Although not part of the AFRIMETS region, NIMT (Thailand) was invited to participate, as a second

institute having participated in APMP.T-K3, to provide confidence in the Comparison Reference Values.

NIMT achieved differences from the CCT-K3 Average Reference Values (ARVs) of ≤ 1.3 mK, with U (k = 2)

of 0.5 mK to 2.7 mK, in APMP.T-K3.

2. PARTICIPANTS

Laboratory Contact person Measurement period

National Metrology Institute of South Africa (NMISA) Mr Hans Liedberg 6 – 10 March 2008

National Institute for Standards, Egypt (NIS) Dr Yasser

Abdelaziz 13 April – 2 May 2009

Metrology Directorate, Quality and Standards

Authority of Ethiopia (QSAE)

(now National Metrology Institute of Ethiopia, NMIE)

Ms Fitsum

Tesfaye 25 June – 1 July 2009

Kenya Bureau of Standards (KEBS) Mr Wilson

Egadwa 9 – 16 September 2009



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National Institute of Metrology, Thailand (NIMT) Mr Uthai Norranim 20 October – 6 November 2009

Uganda National Bureau of Standards (UNBS) Mr Simon

Rwashana 10 – 14 March 2010

Tanzania Bureau of Standards (TBS)

Mr Alphonce

Kagoma, Mr

Adam Ziagi

18 – 20 May 2010

Seychelles Bureau of Standards (SBS) Mr Gilbert

Madeleine 9 June 2010

Mauritius Standards Bureau (MSB) Mr Christian Ng

Ha Kwong 3 August – 3 September 2010

National Metrology Institute of South Africa (NMISA) Mr Hans Liedberg 29 – 31 October 2010

3. ARTEFACTS

High-temperature PRT (0 °C to 450 °C):

Manufacturer: Atexis

Model: TLH600

Serial number: 612

Dimensions: 500 mm long, 5 mm diameter

Low-temperature PRT (-50 °C to 200 °C):

Manufacturer: Burns Engineering

Model: 12001

Serial number: 794332

Dimensions: 356 mm long, 6.35 mm diameter

Digital readout:

Manufacturer: ASL

Model: F250

Serial number: 1228 019 081

4. MEASUREMENT PROCEDURE

The PRTs were annealed by each participant before calibration (one hour at 450 °C for the high-temperature

PRT, two hours at 200 °C for the low-temperature PRT), to place them in a reproducible hysteresis state.

They were measured on local resistance measuring instruments (where available) and on the travelling

readout.

5. MEASUREMENT DATA



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Figures 1 and 2 show the variation in the resistances at the water triple point, as measured by NMISA. They

have been converted to temperature units, to facilitate visual interpretation. Table 1 shows the plotted

values, expressed in resistance units. For determination of Comparison Reference Values (RV), the value of

Rlocal (0.01 °C) on the date of measurement is determined by linear interpolation between the values

measured by NMISA. The difference between Rlocal, NMISA (0.01 °C) values before and after the date of

measurement is included as a component (with coverage factor k = 2√3) in U(RV).

The measurements of R (0.01 °C) on the travelling readout are approximately 4.8 mΩ lower than those on

the local resistance measuring instrument (see Table 1), i.e., Rtravelling(0.01 °C) / Rlocal(0.01 °C) = 0.999 952.

This factor is used to determine Rtravelling (0.01 °C) on the date of measurement, from the value of Rlocal

(0.01 °C), determined as described above.

Values of R (t) reported by participants are converted to resistance ratios W (t) using the above-mentioned

values of R (0.01 °C).

Drift of R(0.01°C)

-0.005

0

0.005

0.01

0.015

0.02

0.025

0.03

0.035

1-Jan-09 2-Apr-09 2-Jul-09 1-Oct-09 1-Jan-10 2-Apr-10 2-Jul-10 2-Oct-10

Date

dR

(°C

)

612 (local readout) 612 (travelling readout)

Figure 1. Variation of R (0.01 °C) during the comparison: high-temperature PRT.



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Drift of R(0.01°C)

0

0.005

0.01

0.015

1-Jan-09 2-Apr-09 2-Jul-09 1-Oct-09 1-Jan-10 2-Apr-10 2-Jul-10 2-Oct-10

Date

dR

(°C

)

794332 (local readout) 794332 (travelling readout)

Figure 2. Variation of R (0.01 °C) during the comparison: low-temperature PRT.

Table 1. Variation of R (0.01 °C) during the comparison.

High-T PRT 612 (local) (travelling) Low-T PRT 794332 (local) (travelling)

Date R(0.01°C) Date R(0.01°C) Date R(0.01°C) Date R(0.01°C)

(ohm) (ohm) (ohm) (ohm)

6-Mar-08 100.00241 13-Oct-08 99.998 6-Mar-08 100.05066 13-Oct-08 100.045

10-Mar-08 100.00229 19-Oct-08 99.997 10-Mar-08 100.05046 19-Oct-08 100.045

22-Jan-09 100.00233 10-Mar-08 100.05032 20-Oct-08 100.045

26-Jan-09 100.00221 3-Oct-09 100.05172 3-Oct-09 100.046

3-Oct-09 100.00520 3-Oct-09 100.000 8-Feb-10 100.05211 8-Feb-10 100.048

8-Feb-10 100.00909 8-Feb-10 100.005 28-May-10 100.05334

28-May-10 100.01321 29-Oct-10 100.05478

29-Oct-10 100.01526 29-Oct-10 100.05442

29-Oct-10 100.01474 30-Oct-10 100.05450

30-Oct-10 100.01378 31-Oct-10 100.05441

Figures 3 and 4 show the differences between the calibrations of the PRTs performed by NMISA. The

means of the deviation functions fitted to the March 2008 and October 2010 data (pink lines in Figures 3 and

4) are used to determine the Reference Value (RV) temperatures from values of resistance ratio W (t). The

difference between the mean deviation function and that fitted to the March 2008 data is included as a

component (with coverage factor k = 2√3) in U (RV).

The mean deviation function coefficients are shown in Table 2.



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Table 2. ITS-90 deviation function coefficients used to determine RV from W (t).

High-T PRT 612 Low-T PRT 794332

Temp range (°C): -50 0.01

a4= -3.7880E-04

b4= 4.6541E-05

Temp range (°C): 0.01 450 Temp range (°C): 0.01 200

a8= -1.7609E-02 a8= -4.0936E-04

b8= -1.3782E-04 b8= -5.9463E-05

Drift of W(t)

-0.01

-0.005

0

0.005

0.01

0 50 100 150 200 250 300 350 400 450

Temperature (°C)

dW

(°C

)

10-Mar-08 (on F18) 19-Oct-08 (on F250 ch A) 31-Oct-10 (on F18) Mean of Mar-08 & Oct-10

Figure 3. Variation of W (t), as measured by NMISA: high-temperature PRT.



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Drift of W(t)

-0.01

-0.005

0

0.005

-50 0 50 100 150 200

Temperature (°C)

dW

(°C

)

10-Mar-08 (on F18) 20-Oct-08 (on F250 ch A) 31-Oct-10 (on F18) Mean of Mar-08 & Oct-10

Figure 4. Variation of W (t), as measured by NMISA: low-temperature PRT.

Channel A of the travelling readout was calibrated for linearity at NMISA, using an RBC100 resistor network,

on 21 April 2008, 8 February 2010 and 27 January 2011. U (k = 2) = 1.4 mΩ was obtained in all three

calibrations. This uncertainty was added to U (RVlocal) to obtain U (RVtravelling). A typical set of results is shown

in Figure 5.

ASL F250 S/N 1228 019 081 ch. A: 2011-01-27

-0.001,6

0.000,0

0.001,6

0 20 40 60 80 100 120 140

Bridge reading

Fit

ted

va

lue

- r

ea

din

g

Ch. A (fitted) Linear (Ch. A (fitted))

Figure 5. Calibration of travelling readout for linearity.



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In Tables 3 - 12 and Figures 6 - 25, the participants’ results are compared to the Reference Values,

determined as described above. NMISA’s results are also compared to RV, to control against errors in

calculation. Values of U (RSS) = √ [ULV2 + URV

2] shown in the figures are those calculated for the local

readout (usually smaller than those for the travelling readout). The normalised error En = (LV – RV) / √ [ULV2

+ URV2] is used to evaluate equivalence: -1 < En <1 is considered a non-discrepant result.

Table 3. NMISA initial results.

Participant: NMISA Date: 10-Mar-08 10-Mar-08 100.0023 dRtp/√3 (°C)

612 (local readout) Rtp (Ω): 100.0023 22-Jan-09 100.0023 0.0001

Actual Resistance U(k=2) RV U(RV) LV-RV En

temperature (°C) (Ω) (°C) (°C) (°C) (°C)

0.010 100.0024 0.0002 0.010 0.002 0.000 -0.15

50.109 119.4899 0.004 50.111 0.004 -0.002 -0.45

125.033 148.0780 0.004 125.036 0.005 -0.003 -0.53

200.004 176.0263 0.004 200.007 0.006 -0.003 -0.46

249.774 194.2215 0.005 249.778 0.006 -0.004 -0.44

351.727 230.6087 0.007 351.729 0.007 -0.002 -0.16

447.924 263.8536 0.008 447.922 0.008 0.002 0.15

0.010 100.0023 0.0002 0.010 0.002 0.000 0.00

612 (trav. readout) Rtp (Ω): 99.9976



0.010 99.9980 0.0002 0.011 0.004 -0.001 -0.22

70.038 127.1510 0.004 70.036 0.006 0.002 0.34

140.077 153.7298 0.004 140.075 0.006 0.001 0.19

200.178 176.0815 0.004 200.179 0.007 0.000 -0.05

251.389 194.7955 0.005 251.386 0.007 0.003 0.35

333.035 224.0165 0.007 333.040 0.008 -0.004 -0.40

448.129 263.9127 0.008 448.132 0.009 -0.003 -0.24

0.010 99.9970 0.0002 0.008 0.004 0.002 0.41

Participant: NMISA Date: 10-Mar-2008 10-Mar-08 100.0503 dRtp/√3 (°C)

794332 (local readout) Rtp (Ω): 100.0503 3-Oct-09 100.0517 0.0021



0.000 0.0000 0.0002

50.111 119.8830 0.004 50.112 0.004 -0.001 -0.17

125.027 148.9752 0.004 125.029 0.005 -0.002 -0.34

200.005 177.4241 0.004 200.010 0.006 -0.005 -0.75

0.010 100.0506 0.0002 0.011 0.003 -0.001 -0.20

-48.024 80.7469 0.001 -48.024 0.003 0.000 0.06

-19.476 92.2540 0.001 -19.477 0.004 0.000 0.02

-9.774 96.1417 0.001 -9.774 0.004 0.000 0.00



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0.010 100.0504 0.0002 0.010 0.003 0.000 -0.06




0.010 100.0450 0.0002 0.009 0.005 0.001 0.22

70.047 127.6820 0.004 70.043 0.006 0.004 0.59

140.076 154.7303 0.004 140.077 0.006 -0.001 -0.11

200.165 177.4720 0.004 200.161 0.007 0.004 0.55

0.010 100.0450 0.0002 0.009 0.005 0.001 0.22

-50.566 79.7135 0.001 -50.566 0.005 0.000 -0.05

-20.195 91.9595 0.001 -20.199 0.005 0.004 0.79

-10.591 95.8085 0.001 -10.595 0.005 0.004 0.82

0.010 100.0450 0.0002 0.009 0.005 0.001 0.22

AFRIMETS.T-S1: high-temperature PRT

-0.04

0

0.04

0 50 100 150 200 250 300 350 400 450

Temperature (°C)

LV

- R

V (

°C)

U(RSS) U(RSS) NMISA 612 (local readout) NMISA 612 (trav. readout)

Figure 6. NMISA initial: high-temperature PRT.



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AFRIMETS.T-S1: low-temperature PRT

-0.04

0

0.04

-50 0 50 100 150 200 250

Temperature (°C)

LV

- R

V (

°C)


Figure 7. NMISA initial: low-temperature PRT.

Table 4. NIS results.

Participant: NIS Date: 23-Apr-2009 26-Jan-09 100.0022 dRtp/√3 (°C)




-0.006 99.9998 0.005 0.001 0.005 -0.007 -0.93

69.974 127.1408 0.017 69.991 0.007 -0.017 -0.94

140.236 153.8074 0.024 140.259 0.009 -0.024 -0.93

200.243 176.2353 0.055 200.569 0.010 -0.326 -5.86

249.905 194.3040 0.026 250.000 0.011 -0.095 -3.43

329.795 222.9131 0.056 329.882 0.012 -0.087 -1.51

419.614 254.1914 0.042 419.639 0.014 -0.025 -0.57

449.545 264.4713 0.258 449.732 0.014 -0.186 -0.72

-0.010 99.9937 0.005 -0.014 0.005 0.004 0.59




-0.007 99.9840 0.005 -0.027 0.006 0.020 2.54

69.896 127.1010 0.017 69.903 0.008 -0.007 -0.38

140.238 153.8230 0.024 140.320 0.009 -0.082 -3.22

200.246 176.1800 0.055 200.442 0.010 -0.195 -3.50



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249.905 194.2800 0.026 249.959 0.011 -0.054 -1.91

329.797 223.0500 0.056 330.298 0.013 -0.501 -8.73

419.607 254.3600 0.042 420.165 0.014 -0.558 -12.63

449.547 264.6600 0.258 450.323 0.015 -0.776 -3.00

-0.008 99.9940 0.005 -0.002 0.006 -0.007 -0.83

Participant: NIS Date: 23-Apr-2009 10-Mar-08 100.0503 dRtp/√3 (°C)




-0.006 100.0354 0.010 -0.030 0.003 0.024 2.26

69.974 127.6325 0.033 69.897 0.005 0.077 2.30

140.236 154.7901 0.009 140.210 0.005 0.026 2.53

200.243 177.5052 0.020 200.221 0.006 0.022 1.03

-0.010 100.0399 0.010 -0.019 0.003 0.009 0.79

-49.898 79.9851 0.010 -49.907 0.003 0.009 0.88

-19.923 92.0717 0.010 -19.933 0.004 0.010 0.99

-9.927 96.0774 0.009 -9.937 0.004 0.010 1.03

-0.010 100.0409 0.010 -0.016 0.003 0.006 0.59




-0.007 100.0340 0.010 -0.021 0.005 0.014 1.26

69.896 127.5640 0.033 69.737 0.006 0.158 4.69

140.238 154.7840 0.009 140.214 0.006 0.024 2.22

200.246 177.4950 0.020 200.218 0.007 0.029 1.34

-0.008 100.0410 0.010 -0.004 0.005 -0.005 -0.43

-49.898 79.9860 0.010 -49.895 0.005 -0.003 -0.26

-19.920 92.0730 0.010 -19.919 0.005 -0.001 -0.13

-9.938 96.0740 0.009 -9.934 0.005 -0.005 -0.43

-0.002 100.0410 0.010 -0.004 0.005 0.002 0.18



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-0.8

-0.6

-0.4

-0.2

0

0.2

0 50 100 150 200 250 300 350 400 450

Temperature (°C)

LV

- R

V (

°C)

U(RSS) U(RSS) NIS 612 (local readout) NIS 612 (trav. readout)

Figure 8. NIS: high-temperature PRT.


-0.04

0

0.04

0.08

0.12

0.16

-50 0 50 100 150 200 250

Temperature (°C)

LV

- R

V (

°C)

U(RSS) U(RSS) NIS 794332 (local readout) NIS 794332 (trav. readout)

Figure 9. NIS: low-temperature PRT.



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Table 5. QSAE (NMIE) results.

Participant: QSAE Date: 28-Jun-2009 26-Jan-09 100.0022 dRtp/√3 (°C)




0.000 100.0004 0.026 0.001 0.005 0.000 -0.01

70.182 127.2163 0.038 70.185 0.007 -0.003 -0.08

140.103 153.7495 0.232 140.102 0.009 0.002 0.01

199.819 175.9782 0.232 199.868 0.010 -0.049 -0.21

248.656 193.8523 0.693 248.751 0.011 -0.095 -0.14

328.943 222.5927 0.693 328.971 0.012 -0.028 -0.04

419.258 254.0763 0.694 419.298 0.014 -0.040 -0.06

448.986 264.2323 0.702 449.022 0.014 -0.037 -0.05

-0.001 100.0006 0.026 0.001 0.005 -0.002 -0.08




0.000 100.0000 0.026 0.012 0.006 -0.011 -0.41

70.185 127.2100 0.038 70.184 0.008 0.001 0.03

140.103 153.7500 0.232 140.122 0.009 -0.019 -0.08

199.824 175.9740 0.232 199.879 0.010 -0.055 -0.24

248.595 193.7980 0.693 248.626 0.011 -0.031 -0.05

329.038 222.6070 0.693 329.041 0.013 -0.002 0.00

419.264 254.0660 0.694 419.302 0.014 -0.038 -0.05

449.271 264.3080 0.702 449.281 0.015 -0.010 -0.01

0.000 100.0000 0.026 0.012 0.006 -0.012 -0.44

Participant: QSAE Date: 28-Jun-2009 10-Mar-08 100.0503 dRtp/√3 (°C)




0.000 100.0473 0.026 0.000 0.003 0.001 0.03

70.183 127.7432 0.033 70.180 0.005 0.003 0.11

140.105 154.7523 0.232 140.110 0.005 -0.005 -0.02

199.834 177.3682 0.232 199.855 0.006 -0.022 -0.09

0.001 100.0475 0.026 0.000 0.003 0.001 0.03

-50.059 79.9240 0.037 -50.058 0.003 -0.001 -0.03

-19.931 92.0727 0.037 -19.931 0.004 0.001 0.01

-10.030 96.0398 0.028 -10.031 0.004 0.002 0.06

0.000 100.0478 0.026 0.001 0.003 0.000 -0.01






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0.000 100.0460 0.026 0.009 0.005 -0.008 -0.31

70.181 127.7400 0.033 70.188 0.006 -0.007 -0.20

140.100 154.7410 0.232 140.100 0.006 0.000 0.00

199.830 177.3600 0.232 199.857 0.007 -0.027 -0.12

0.001 100.0460 0.026 0.009 0.005 -0.008 -0.29

-50.065 79.9200 0.037 -50.058 0.005 -0.006 -0.17

-19.948 92.0600 0.037 -19.951 0.005 0.003 0.09

-10.027 96.0400 0.028 -10.019 0.005 -0.008 -0.27

0.000 100.0430 0.026 0.001 0.005 -0.001 -0.02


-0.12

-0.08

-0.04

0

0.04

0.08

0 50 100 150 200 250 300 350 400 450

Temperature (°C)

LV

- R

V (

°C)

U(RSS) U(RSS) QSAE 612 (local readout) QSAE 612 (trav. readout)

Figure 10. QSAE (NMIE): high-temperature PRT.



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-0.08

-0.04

0

0.04

0.08

-50 0 50 100 150 200 250

Temperature (°C)

LV

- R

V (

°C)

U(RSS) U(RSS) QSAE 794332 (local readout) QSAE 794332 (trav. readout)

Figure 11. QSAE (NMIE): low-temperature PRT.

Table 6. KEBS results.

Participant: KEBS Date: 13-Sep-2009 26-Jan-09 100.0022 dRtp/√3 (°C)




-0.013 99.9871 0.053 -0.036 0.005 0.022 0.42

70.001 127.1405 0.064 69.985 0.007 0.016 0.25

139.603 153.5485 0.071 139.563 0.009 0.040 0.56

200.023 176.0294 0.065 200.003 0.010 0.020 0.31

250.114 194.4985 0.082 250.527 0.011 -0.413 -4.98

329.155 222.8777 0.130 329.771 0.012 -0.617 -4.72

419.755 254.4800 0.133 420.467 0.014 -0.713 -5.32

449.509 264.6647 0.155 450.287 0.014 -0.778 -4.99

0.002 99.9955 0.053 -0.014 0.005 0.017 0.31




-0.013 99.9870 0.053 -0.024 0.006 0.011 0.20

69.997 127.1346 0.064 69.985 0.008 0.013 0.20

139.601 153.5427 0.071 139.566 0.009 0.035 0.49

200.022 176.0254 0.065 200.014 0.010 0.008 0.12



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250.160 194.5111 0.082 250.587 0.011 -0.427 -5.15

329.167 222.8792 0.130 329.805 0.013 -0.637 -4.88

419.734 254.4733 0.133 420.482 0.014 -0.748 -5.59

449.420 264.6382 0.155 450.246 0.015 -0.825 -5.29

0.002 99.9940 0.053 -0.006 0.006 0.008 0.16

Participant: KEBS Date: 13-Sep-2009 10-Mar-08 100.0503 dRtp/√3 (°C)




-0.009 100.0391 0.055 -0.022 0.003 0.012 0.22

70.002 127.6686 0.063 69.988 0.005 0.014 0.22

139.580 154.5312 0.069 139.531 0.005 0.050 0.72

199.929 177.3933 0.075 199.921 0.006 0.007 0.10

-0.011 100.0392 0.055 -0.021 0.003 0.010 0.19

-10.623 95.7954 0.054 -10.643 0.004 0.019 0.35

-0.017 100.0390 0.055 -0.022 0.003 0.005 0.09




-0.009 100.0360 0.055 -0.017 0.005 0.008 0.14

70.001 127.6623 0.063 69.988 0.006 0.013 0.21

139.580 154.5259 0.069 139.537 0.006 0.044 0.63

199.949 177.3956 0.075 199.951 0.007 -0.002 -0.02

-0.011 100.0360 0.055 -0.017 0.005 0.006 0.11

-10.659 95.7811 0.054 -10.667 0.005 0.008 0.14

-0.017 100.0360 0.055 -0.017 0.005 0.000 0.00



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-1

-0.8

-0.6

-0.4

-0.2

0

0.2

0 50 100 150 200 250 300 350 400 450

Temperature (°C)

LV

- R

V (

°C)

U(RSS) U(RSS) KEBS 612 (local readout) KEBS 612 (trav. readout)

Figure 12. KEBS: high-temperature PRT.


-0.08

-0.04

0

0.04

0.08

-50 0 50 100 150 200 250

Temperature (°C)

LV

- R

V (

°C)

U(RSS) U(RSS) KEBS 794332 (local readout) KEBS 794332 (trav. readout)

Figure 13. KEBS: low-temperature PRT.



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Table 7. NIMT results.

Participant: NIMT Date: 28-Oct-2009 3-Oct-09 100.0052 dRtp/√3 (°C)

612 (local readout) Rtp (Ω): 100.0060 8-Feb-10 100.0091 0.0058



-0.003 99.9982 0.014 -0.010 0.006 0.007 0.43

70.002 127.1458 0.022 69.995 0.009 0.007 0.30

140.004 153.7124 0.018 139.995 0.010 0.009 0.42

200.001 176.0268 0.008 199.991 0.012 0.010 0.69

250.003 194.3081 0.016 249.997 0.013 0.006 0.29

330.001 222.9599 0.022 329.997 0.015 0.003 0.13

419.995 254.3103 0.032 419.965 0.017 0.030 0.82

450.012 264.5657 0.032 449.988 0.017 0.023 0.63

0.005 100.0031 0.014 0.003 0.006 0.002 0.12




-0.003 99.9940 0.014 -0.009 0.007 0.006 0.37

70.004 127.1390 0.022 69.993 0.009 0.011 0.47

140.004 153.7050 0.018 139.994 0.011 0.010 0.47

200.001 176.0180 0.008 199.989 0.012 0.012 0.84

250.005 194.2980 0.016 249.994 0.013 0.011 0.52

329.998 222.9450 0.022 329.984 0.015 0.013 0.50

419.995 254.3010 0.032 419.973 0.017 0.023 0.62

450.016 264.5590 0.032 450.005 0.018 0.011 0.30

0.004 99.9990 0.014 0.004 0.007 -0.001 -0.04

Participant: NIMT Date: 28-Oct-2009 3-Oct-09 100.0517 dRtp/√3 (°C)

794332 (local readout) Rtp (Ω): 100.0518 8-Feb-10 100.0521 0.0006



-0.003 100.0445 0.010 -0.008 0.002 0.005 0.47

70.003 127.6723 0.008 69.997 0.004 0.006 0.61

140.003 154.7104 0.008 139.999 0.004 0.004 0.49

200.001 177.4212 0.008 199.995 0.005 0.006 0.59

0.001 100.0433 0.010 -0.011 0.002 0.012 1.20

-50.000 79.9460 0.008 -50.005 0.003 0.005 0.56

-20.000 92.0436 0.008 -20.004 0.003 0.005 0.53

-10.002 96.0498 0.008 -10.007 0.003 0.005 0.55

-0.007 100.0429 0.010 -0.012 0.002 0.005 0.53






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-0.003 100.0410 0.010 -0.005 0.004 0.002 0.18

70.003 127.6670 0.008 70.000 0.005 0.004 0.39

140.004 154.7050 0.008 140.005 0.005 -0.001 -0.07

200.002 177.4130 0.008 199.997 0.006 0.005 0.50

-0.005 100.0400 0.010 -0.007 0.004 0.002 0.19

-49.998 79.9420 0.008 -50.005 0.005 0.007 0.71

-19.998 92.0380 0.008 -20.007 0.005 0.009 1.00

-10.003 96.0450 0.008 -10.007 0.005 0.005 0.52

0.000 100.0430 0.010 0.000 0.004 0.000 -0.03


-0.04

0

0.04

0 50 100 150 200 250 300 350 400 450

Temperature (°C)

LV

- R

V (

°C)

U(RSS) U(RSS) NIMT 612 (local readout) NIMT 612 (trav. readout)

Figure 14. NIMT: high-temperature PRT.



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-0.04

0

0.04

-50 0 50 100 150 200 250

Temperature (°C)

LV

- R

V (

°C)

U(RSS) U(RSS) NIMT 794332 (local readout) NIMT 794332 (trav. readout)

Figure 15. NIMT: low-temperature PRT.

Table 8. UNBS results.

Participant: UNBS Date: 12-Mar-2010 8-Feb-10 100.0091 dRtp/√3 (°C)

612 (local readout) Rtp (Ω): 100.0103 28-May-10 100.0132 0.0061



0.130 100.0505 0.662 0.113 0.006 0.017 0.03

70.060 127.0520 1.142 69.736 0.009 0.324 0.28

140.180 153.9000 0.786 140.477 0.011 -0.297 -0.38

200.560 176.2990 0.680 200.709 0.012 -0.149 -0.22

250.120 194.5540 0.558 250.652 0.013 -0.532 -0.95

0.140 100.0542 0.662 0.122 0.006 0.018 0.03




0.130 100.0460 0.662 0.113 0.007 0.017 0.03

70.060 127.1540 1.142 70.017 0.010 0.043 0.04

140.180 153.9710 0.786 140.685 0.011 -0.505 -0.64

200.580 176.3920 0.680 200.983 0.013 -0.403 -0.59

250.120 195.6690 0.558 253.753 0.014 -3.633 -6.51

0.140 100.0510 0.662 0.126 0.007 0.014 0.02

Participant: UNBS Date: 12-Mar-2010 8-Feb-10 100.0521 dRtp/√3 (°C)



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0.130 101.6290 0.785 3.965 0.003 -3.835 -4.88

70.060 127.5210 1.221 69.607 0.005 0.453 0.37

140.320 154.9170 0.901 140.537 0.005 -0.217 -0.24

200.610 177.7080 0.815 200.757 0.006 -0.147 -0.18

0.090 99.9540 0.785 -0.237 0.003 0.327 0.42

-19.950 91.8720 0.786 -20.433 0.003 0.483 0.61

-9.890 96.0812 0.793 -9.930 0.003 0.040 0.05

0.130 100.0730 0.785 0.061 0.003 0.069 0.09




0.130 100.0900 0.785 0.116 0.004 0.014 0.02

70.060 127.6790 1.221 70.028 0.006 0.032 0.03

140.180 154.8530 0.901 140.390 0.006 -0.210 -0.23

200.670 177.7360 0.815 200.855 0.007 -0.185 -0.23

0.090 99.9480 0.785 -0.240 0.004 0.330 0.42

-19.950 92.0820 0.786 -19.899 0.005 -0.051 -0.07

-9.890 96.0880 0.793 -9.901 0.005 0.011 0.01

0.130 100.0660 0.785 0.056 0.004 0.074 0.09


-1.2

-0.8

-0.4

0

0.4

0 50 100 150 200 250 300 350 400 450

Temperature (°C)

LV

- R

V (

°C)

U(RSS) U(RSS) UNBS 612 (local readout) UNBS 612 (trav. readout)



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Figure 16. UNBS: high-temperature PRT.


-1.2

-0.8

-0.4

0

0.4

0.8

-50 0 50 100 150 200 250

Temperature (°C)

LV

- R

V (

°C)

U(RSS) U(RSS) UNBS 794332 (local readout) UNBS 794332 (trav. readout)

Figure 17. UNBS: low-temperature PRT.

Table 9. TBS results.

Participant: TBS Date: 19-May-2010 8-Feb-10 100.0091 dRtp/√3 (°C)





0.000 100.0400 0.040 0.091 0.007 -0.091 -2.23

70.000 127.1700 0.046 70.051 0.010 -0.051 -1.08

140.000 153.7400 0.043 140.059 0.011 -0.059 -1.33

200.000 176.0600 0.046 200.070 0.013 -0.070 -1.48

251.821 195.0400 0.050 252.003 0.014 -0.182 -3.52

335.868 225.0600 0.056 335.928 0.016 -0.060 -1.02

427.911 257.0100 0.063 427.822 0.018 0.089 1.35

457.055 266.9400 0.079 456.965 0.019 0.090 1.11

0.000 100.0300 0.040 0.066 0.007 -0.066 -1.61

Participant: TBS Date: 19-May-2010 8-Feb-10 100.0521 dRtp/√3 (°C)




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0.000 100.0600 0.040 0.039 0.004 -0.039 -0.97

70.000 127.6900 0.046 70.054 0.006 -0.054 -1.17

140.000 154.7200 0.043 140.038 0.006 -0.038 -0.88

200.000 177.4300 0.046 200.035 0.007 -0.035 -0.76

0.000 100.0600 0.040 0.039 0.004 -0.039 -0.97

-40.000 83.9800 0.056 -40.026 0.005 0.026 0.45

-20.000 92.0300 0.046 -20.030 0.005 0.030 0.66

-10.000 96.0400 0.041 -10.023 0.005 0.023 0.57

0.000 100.0600 0.040 0.039 0.004 -0.039 -0.97


-0.2

-0.16

-0.12

-0.08

-0.04

0

0.04

0.08

0.12

0 50 100 150 200 250 300 350 400 450

Temperature (°C)

LV

- R

V (

°C)

U(RSS) U(RSS) TBS 612 (local readout) TBS 612 (trav. readout)

Figure 18. TBS: high-temperature PRT.



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-0.08

-0.04

0

0.04

0.08

-50 0 50 100 150 200 250

Temperature (°C)

LV

- R

V (

°C)

U(RSS) U(RSS) TBS 794332 (local readout) TBS 794332 (trav. readout)

Figure 19. TBS: low-temperature PRT.

Table 10. SBS results.

Participant: SBS Date: 9-Jun-2010 28-May-10 100.0132 dRtp/√3 (°C)





100.003 138.5689 0.000 99.898 0.007 0.105 14.46

Participant: SBS Date: 9-Jun-2010 28-May-10 100.0533 dRtp/√3 (°C)





-20.020 92.2078 0.000 -19.588 0.005 -0.432 -86.20



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0

0.04

0.08

0.12

0 50 100 150 200 250 300 350 400 450

Temperature (°C)

LV

- R

V (

°C)

U(RSS) U(RSS) SBS 612 (local readout) SBS 612 (trav. readout)

Figure 20. SBS: high-temperature PRT.


-0.6

-0.4

-0.2

0

-50 0 50 100 150 200 250

Temperature (°C)

LV

- R

V (

°C)

U(RSS) U(RSS) SBS 794332 (local readout) SBS 794332 (trav. readout)

Figure 21. SBS: low-temperature PRT.



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Table 11. MSB results.

Participant: MSB Date: 18-Aug-2010 28-May-10 100.0132 dRtp/√3 (°C)





0.020 100.0050 0.042 -0.002 0.005 0.022 0.52

70.044 127.1610 0.051 70.022 0.007 0.022 0.42

139.999 153.4020 0.056 139.153 0.008 0.846 14.91

200.025 176.1040 0.067 200.183 0.009 -0.158 -2.33

250.003 194.3980 0.072 250.225 0.009 -0.222 -3.04

329.935 223.0560 0.083 330.246 0.010 -0.311 -3.72

420.064 254.4990 0.094 420.488 0.012 -0.424 -4.48

449.843 264.6850 0.101 450.311 0.012 -0.468 -4.58

0.004 100.0000 0.042 -0.015 0.005 0.019 0.44

Participant: MSB Date: 18-Aug-2010 28-May-10 100.0533 dRtp/√3 (°C)





0.020 100.0430 0.042 -0.006 0.005 0.026 0.61

70.032 127.6770 0.051 70.018 0.006 0.014 0.28

140.006 154.6890 0.056 139.954 0.006 0.052 0.93

200.005 177.5110 0.067 200.247 0.007 -0.242 -3.59

0.004 100.0380 0.042 -0.018 0.005 0.022 0.53

-20.009 91.9420 0.052 -20.251 0.005 0.242 4.63

-10.018 95.9520 0.053 -10.245 0.005 0.227 4.28

0.013 100.0420 0.042 -0.008 0.005 0.021 0.50



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-0.6

-0.4

-0.2

0

0.2

0.4

0.6

0.8

1

0 50 100 150 200 250 300 350 400 450

Temperature (°C)

LV

- R

V (

°C)

U(RSS) U(RSS) MSB 612 (local readout) MSB 612 (trav. readout)

Figure 22. MSB: high-temperature PRT.


-0.4

-0.2

0

0.2

0.4

-50 0 50 100 150 200 250

Temperature (°C)

LV

- R

V (

°C)

U(RSS) U(RSS) MSB 794332 (local readout) MSB 794332 (trav. readout)

Figure 23. MSB: low-temperature PRT.



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Table 12. NMISA final results.

Participant: NMISA Date: 29-Oct-10 29-Oct-10 100.0147 dRtp/√3 (°C)

612 (local readout) Rtp (Ω): 100.0146 30-Oct-10 100.0138 -0.0014



0.000 100.0108 0.0023 0.000 0.002 0.000 -0.12

100.160 138.6765 0.007 100.160 0.005 0.000 -0.01

205.482 178.0611 0.008 205.475 0.006 0.007 0.75

328.525 222.4563 0.013 328.519 0.008 0.006 0.43

449.618 264.4641 0.017 449.622 0.009 -0.004 -0.20

0.000 100.0099 0.0023 -0.002 0.002 0.002 0.60

Participant: NMISA Date: 29-Oct-2010 29-Oct-10 100.0544 dRtp/√3 (°C)




0.000 100.0504 0.0023

50.105 119.8847 0.005 50.104 0.003 0.002 0.30

150.003 158.5310 0.004 150.003 0.004 0.000 0.07

205.383 179.4429 0.004 205.378 0.005 0.005 0.79

0.000 100.0505 0.0023 0.000 0.002 0.000 -0.03

-49.198 80.2749 0.002 -49.198 0.003 0.000 -0.09

-34.694 86.1369 0.002 -34.694 0.003 0.000 -0.11

-19.826 92.1178 0.002 -19.825 0.003 0.000 -0.03

0.000 100.0504 0.0023 0.000 0.002 0.000 0.04



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-0.04

0

0.04

0 50 100 150 200 250 300 350 400 450

Temperature (°C)

LV

- R

V (

°C)


Figure 24. NMISA final: high-temperature PRT.


-0.04

0

0.04

-50 0 50 100 150 200 250

Temperature (°C)

LV

- R

V (

°C)


Figure 25. NMISA final: low-temperature PRT.



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6. CONCLUSIONS

This comparison allowed evaluation of the IPRT calibration capabilities of the participants at the 0.02 °C

level. Circulation of a digital readout with the PRTs allowed the participation of laboratories that did not have

a resistance measuring instrument suitable for measuring the travelling PRTs.

There were several discrepant results (difference from the Reference Value larger than the uncertainty of the

difference). Participants are encouraged to apply several techniques for assuring the quality of results, to

gain confidence in the results of their calibrations. Some techniques that can be applied to a PRT calibration

are:

(i) ITS-90 deviation functions can be fitted to the measured data, using the least squares technique [2]. The

number of fitted coefficients should be less than the number of data points. (For example, fit a linear or

quadratic deviation function to three or more data points.) Fit residuals which are larger than the estimated

uncertainties may indicate unidentified errors in measurement.

(ii) If two readouts are used, the consistency of the two data sets can be examined.

7. REFERENCES

[1] APMP-KC3: Key comparison of realization of the ITS-90 over the range -38.8344 °C to 419.527 °C

(final report, prepared by M. K. Nguyen and M. J. Ballico, NMIA, Lindfield, Australia. 7 Oct. 2005).

[2] H. Liedberg, “Fitting curves to thermocouple and platinum resistance thermometer calibration data,"

in Proc. of NLA/MIG Test & Measurement Conference 2005.



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APPENDIX 1: PROTOCOL FOR AFRIMETS.T-S1

PROCEDURES FOR THE AFRIMETS REGIONAL COMPARISON OF

PLATINUM RESISTANCE THERMOMETER AND DIGITAL THERMOMETER CALIBRATIONS AGAINST

ITS-90 OVER THE RANGE -50 °C TO 450 °C (AFRIMETS.T-S1)

30 March 2009

H. Liedberg

National Metrology Institute of South Africa (NMISA)

Private Bag X34, 0040 Lynnwood Ridge, South Africa

Tel: +27-12-841 2753, Fax: +27-12-841 2131

E-mail: [email protected]

INTRODUCTION

This AFRIMETS regional supplementary comparison is being coordinated by the National Metrology Institute

of South Africa (NMISA), and extends from -50 °C to 450 °C. The comparison was proposed in the April

2002 report of pilot comparison SADC.T-P1 (liquid-in-glass thermometers from 0 °C to 50 °C). Invitations to

participate were sent to all SADC countries. The countries that indicated their readiness to participate are

listed in the attached Circulation Schedule.

Each participant will calibrate two platinum resistance thermometers (PRTs) and arrange for their transport

to the next participating laboratory. The Circulation Schedule for AFRIMETS.T-S1, as at March 2009, is

included as an Appendix. The comparison results will be analysed by the pilot laboratory (NMISA).

The instructions which are given below should be followed by all participants in this comparison.

The travelling thermometers are to pass through the following sequence:

High-temperature PRT (0 to 450 °C):

1) a measurement at the water triple point (0.01 °C) or ice point (0.00 °C)

2) a stabilisation procedure (annealing for one hour at 450 °C)

3) a second measurement at the water triple point or ice point

4) comparison with reference thermometer(s) at 70, 140, 200, 250, 330, 420 and 450 °C

5) a third measurement at the water triple point or ice point

Low-temperature PRT (-50 to 200 °C):

1) a measurement at the water triple point (0.01 °C) or ice point (0.00 °C)

2) a stabilisation procedure (annealing for two hours at 200 °C)

3) a second measurement at the water triple point or ice point



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2) comparison with reference thermometer(s) at 70, 140 and 200 °C

3) a third measurement at the water triple point or ice point

2) comparison with reference thermometer(s) at -50, -20, and -10 °C

5) a fourth measurement at the water triple point or ice point

The travelling thermometer details are as follows:

High-temperature PRT:


Model: TLH600

Serial number: 612


Low-temperature PRT:


Model: 12001



Back-up thermometers of the same types are also circulated. If one of the above thermometers is damaged

during transit, the measurements may be performed on the back-up thermometer instead.

The details of the back-up thermometers are as follows:

High-temperature PRT:


Model: TLH600

Serial number: 616


Low-temperature PRT:


Model: 12001



A digital readout is circulated with the PRTs. Its details are as follows:

Description: Digital readout

Manufacturer: ASL

Model: F250




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Dimensions: 250 x 290 x 90 mm

The thermometer artefacts and digital readout are sensitive to mechanical shock, so they must be handled

with care. For transport, the PRTs and readout should be packed in the accompanying protective case.

DETAILED INSTRUCTIONS

1. Upon receipt of the PRTs and digital readout, the host laboratory should inspect them for damage. If any

of the travelling artefacts is damaged, contact the pilot laboratory for instructions on how to proceed.

If no damage has been sustained, the host should measure the resistances of the two travelling PRTs in a

water triple point cell (0.01 °C) or ice point (0.00 °C).

If a suitable instrument for measuring electrical resistance is available in the participating lab, the two PRTs

should be measured on this instrument, as well as on channel A of the digital readout circulated with the

PRTs. (The resistance reading of the travelling digital readout should be recorded, not the temperature

reading.) If the host does not have a suitable instrument for measuring electrical resistance, the PRTs need

only be measured on the travelling digital readout (on channel A).

If the host uses his own resistance measuring instrument, an excitation current of 1 mA or 0.5 mA should be

used. If the host's resistance measuring instrument has the facility to change the excitation current, the self-

heating of the travelling PRTs should be measured by increasing or decreasing the current by a factor of √2.

The host should complete and forward (by e-mail or fax) the attached Artefact Received form to the pilot

laboratory, reporting the condition of the artefacts and the initial values of R (0.01°C) or R (0 °C).

2. Anneal the high-temperature PRT for one hour at 450 °C and the low-temperature PRT for two hours at

200 °C, in order to remove strains induced during transport and to place the resistance elements in a

reproducible state of hysteresis and oxidation. (If the host does not have a bath or furnace capable of

reaching the required annealing temperature, the low-temperature PRT may be annealed at the maximum

temperature achievable by the host, if this is lower than 200 °C. However, the high-temperature PRT should

not be annealed at a temperature below 450 °C, to avoid the formation of platinum oxide on the surface of

the resistance element.) After the annealing period, remove the PRT from the bath or furnace directly to

room temperature. After the PRTs have cooled to room temperature, re-determine R (0.01°C) or R (0 °C) as

per instruction 1.

3. If the change in R (0.01°C) or R (0 °C) of either of the PRTs is greater than 0.002 Ω, re-anneal that PRT

as per instruction 2, then re-measure R (0.01°C) or R (0 °C). If the change in R (0.01°C) or R (0 °C) after the

second anneal is greater than 0.002 Ω, contact the pilot laboratory for instructions on how to proceed.

4. Perform the measurements described below in the specified order, so that the PRTs' hysteresis is

reproducible. Record the approximate immersion depth of the tip of the PRT in the water triple point cell or

ice point, and in each bath or furnace.



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Compare the high-temperature PRT to local reference thermometer(s) at 70, 140, 200, 250, 330, 420 and

450 °C. Remove the PRT from the bath or furnace directly to room temperature. After the PRT has cooled to

room temperature, measure R (0.01°C) or R (0 °C).

Compare the low-temperature PRT to local reference thermometer(s) at 70, 140 and 200 °C. Measure R

(0.01°C) or R (0 °C). Compare the low-temperature PRT to local reference thermometer(s) at -50, -20 and

-10 °C. Measure R (0.01°C) or R (0 °C).

5. Report the results to the pilot laboratory using the attached Measurement Data form. Complete the

Instrumentation form and one Uncertainty Analysis form for each calibration temperature, and forward these

to the pilot laboratory.

Uncertainty analysis

Methods of estimating some of the uncertainty contributions listed on the Uncertainty Analysis form are given

below:

The drift of the reference thermometer since its last calibration may be estimated from its history: difference

between last and second last calibrations (at relevant temperature) / (months between last and second last

calibrations) x (months since last calibration)

Stability of R(0.01°C) or R(0°C) of the reference thermometer (if it is a PRT) or travelling PRT: The

uncertainty in the estimated value of R(0.01°C) or R(0°C) during measurement depends on the way in which

this value is estimated: if [R(0.01°C, before measurement) + R(0.01°C, after measurement)] / 2 is used, then

the uncertainty (half-width of a rectangular distribution) is

[R (0.01°C, before measurement) - R (0.01°C, after measurement)] / 2.

If R (0.01°C, before measurement) is used, then the uncertainty is

[R (0.01°C, before measurement) - R (0.01°C, after measurement)].

If R (0.01°C, during last calibration) is used for the reference PRT, then the uncertainty is

[R (0.01°C, during last calibration) - R (0.01°C, after measurement)].

This uncertainty should be propagated to the calibration temperature by multiplying by the resistance ratio at

the calibration temperature, W (t) = R (t) / R (0.01°C).

Example: Uncertainty contribution at 450 °C due to instability in R (0.01°C) of 25 Ω reference standard PRT:

R (0.01°C) of the reference PRT is measured before and after use:

R (0.01°C, before) = 24.812 5 Ω and R (0.01°C, after) = 24.812 4 Ω

[R (0.01°C, before measurement) + R (0.01°C, after measurement)] / 2 is used to calculate W

The actual temperature is calculated using this value of W

u (k=1) = [R (0.01°C, before) - R (0.01°C, after)] / 2 / √3 x W (450°C) x dt/dR

= (24.812 5 Ω – 24.812 4 Ω) / 2 / √3 x 2.67 x 11.6°C/Ω

= 0.000 9 °C

Example: Uncertainty contribution at 450 °C due to instability in R (0°C) of 100 Ω reference industrial PRT:



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the resistance-temperature table in the PRT's calibration certificate is used to calculate the actual

temperature, i.e. R (0.01°C, during last calibration) is used:

R (0.01°C, during last calibration) = 100.014 5 Ω

R (0°C) of the reference PRT is measured after use: R (0°C, after) = 100.011 4 Ω. R (0.01°C, after)

is calculated: R (0.01°C, after) = R (0°C, after) / W (0°C) = 100.011 4 Ω / 0.999 960 9 = 100.015 3 Ω

u (k=1) = [R (0.01°C, during last cal) - R (0.01°C, after)] / √3 x W (450°C) x dt/dR

= (100.014 5 Ω – 100.015 3 Ω) / √3 x 2.64 x 2.95°C/Ω

= 0.003 6 °C

Uncertainty of reference temperature (water triple point or ice point): The uncertainty in the temperature of

the water triple point or ice point should be propagated to the calibration temperature by multiplying by the

resistance ratio at the calibration temperature, W(t) = R(t) / R(0.01°C).

Uncertainty of electrical measuring instrument:

Example: A resistance bridge with an accuracy specification of ± 1 ppm of the full-scale reading is used to

measure a 25 Ω reference PRT (at 450 °C) vs a 100 Ω standard resistor:

bridge ratio = R (t) / R (std), i.e. R (t) = bridge ratio x R (std)

u (k=1) = u (bridge ratio) / √3 x R (std) x dt/dR

= 0.000 001 / √3 x 100 Ω x 11.6°C/Ω

= 0.000 7 °C

Example: The 1 kΩ range of a digital multimeter is used to measure a 100 Ω PRT (at 450 °C):

Uncertainty of calibration of DMM: Uc (k=2) = 3mΩ + 2∙10-5

∙R

As DMMs are prone to drift (more so than resistance bridges) and it has been 3 months since the

DMM's last calibration, the 90-day drift specification of the DMM is also taken into account:

± (0.008% of reading + 0.001% of range)

dRdtku /]3

100010264108[]

2

264102003.0[)1( 2

552

5

= √ [0.004 1 Ω] 2 + [0.018 0 Ω]

2 ∙ 2.95°C/Ω

= 0.054 °C

Temperature gradient in bath / furnace (including stem conduction error): The results of the most recent

evaluation of the heat source should preferably be used, where available. Otherwise, the temperature

gradients in the heat source may be estimated by using more than one reference thermometer, or the

uniformity specification published by the manufacturer of the bath or furnace may be used. The largest

expected temperature difference between the reference thermometer and travelling PRT should be used as

the half-width of a rectangular distribution.

Repeatability: The standard deviation of the mean of several readings of the reference thermometer and

travelling PRT should be used. By taking readings over several minutes (more than one control cycle of the



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bath/furnace), the effect of instability in the bath/furnace temperature (and different response times of the

thermometers) will be included in the standard deviation of the mean.

Example: It is preferable to use a "sandwich" measurement technique (ref1, ref2, travelling PRT, ref2, ref1),

to calculate a correction for the travelling PRT for every "sandwich" set of measurements, and to use the

standard deviation of the mean of the corrections, rather than to consider the variations in the temperatures

of the reference and travelling thermometers separately. (In the example below, the ITS-90 reference

functions are used to calculate temperatures from the measured resistance values of the travelling PRT.)

Reference PRT Travelling PRT Rtp (Ω): 100.01450

Time t(actual) (°C) Mean R (Ω) W t (°C) Correction (°C)

15:51:48 29.9227

15:52:18 29.9210 111.65649 1.1164031 29.3254 0.5955

15:52:48 29.9193

15:56:03 29.9185

15:56:33 29.9174 111.65490 1.1163872 29.3214 0.5960

15:57:03 29.9163

15:59:56 29.9143

16:00:26 29.9131 111.65327 1.1163708 29.3173 0.5958

16:00:56 29.9119

16:06:44 29.9077

16:07:14 29.9073 111.65093 1.1163474 29.3114 0.5960

16:07:44 29.9069

16:08:19 29.9055

16:08:49 29.9055 111.65059 1.1163441 29.3105 0.5950

16:09:19 29.9056

Mean: 29.9129 111.65324 1.1163705 29.3172 0.5957

Std dev: 0.0065 0.00254 0.0000253 0.0064 0.0004

No of readings: 5 5 5 5 5

Std dev of mean 0.0029 0.00113 0.0000113 0.0029 0.0002

In this example, the standard deviation of the mean of the reference PRT readings is 0.002 9 °C, that of the

travelling PRT readings is 0.002 9 °C, but that of the corrections (reference PRT – travelling PRT) is only

0.000 2 °C.

TRANSPORTATION

Packaging

Before shipping, the PRTs and readout should be carefully packed in the accompanying protective case.

Transport

The host laboratory is responsible for transport of the thermometers to the next laboratory on the Circulation

Schedule. The thermometers may be transported unaccompanied or accompanied. In either case, they

should be packed as described above before transport.

Circulation schedule



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Please forward the Artefact Shipped form to NMISA and to the next laboratory on the Circulation Schedule.

The circulation schedule allows 3 weeks for measurements and 2 weeks for transport between laboratories.

Please try to complete measurements and send the completed Measurement Data form to NMISA within the

first 2 weeks, so that any additional measurements requested by NMISA may be completed by the end of the

3rd week.

APPENDIX A: CUSTOMS DECLARATION

TO WHOM IT MAY CONCERN

The SADC Cooperation in Measurement Traceability (SADCMET) is an agency representing the National

Measurement / Standards Laboratories of Angola, Botswana, Democratic Republic of Congo (DRC),

Lesotho, Malawi, Mauritius, Mozambique, Namibia, Seychelles, South Africa, Swaziland, Tanzania, Zambia

and Zimbabwe. Its broad objective is to coordinate measurement activities and services in the SADC region,

in order to provide regional calibration and testing services with readily available traceability to the SI units of

measurement.

As part of an intercomparison program, SADCMET is conducting an intercomparison of realisations of the

International Temperature Scale of 1990 (ITS-90) in the temperature range -50°C to 450°C involving the

participants as given in the Circulation Schedule.

This intercomparison is coordinated by:

National Metrology Institute of South Africa (NMISA)

Private Bag X34

ZA-0040 Lynnwood Ridge

South Africa

The following artefacts are circulated among the participants for measurement:

Description: Platinum resistance thermometers

Manufacturer: Atexis & Burns Engineering

Serial numbers: 612, 794332, 616 and 794333

Description: Digital readout

Manufacturer: ASL

Model: F250


The purchase cost of the platinum resistance thermometers was ZAR 5000 each, and that of the digital

readout was ZAR 33000. However, they have no commercial value (they are not for sale). They are meant



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solely for the comparison of national standards and will be re-exported immediately after the measurements

are completed (see enclosed Circulation Schedule).

We request that the devices are not handled or removed from the container/package. If a Customs

inspection is required, please contact the relevant person listed in the attached schedule, so that he/she can

be present and help you unpack it.

....................................................

Comparison coordinator

Hans Liedberg, NMISA

International phone number: +27-12-841 2753

International fax number: +27-12-841 4458

E-mail: [email protected]



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APPENDIX B: CIRCULATION SCHEDULE FOR REGIONAL COMPARISON AFRIMETS.T-S1

Laboratory Contact person Time allocated

NMISA, South Africa Mr Hans Liedberg

National Institute for Standards, Egypt Dr. Khalid Ali 13 April – 3 May 2009

Quality and Standards Authority of Ethiopia Mr Wondwosen Fisseha / Ms Fitsum Tesfaye 18 May – 7 June 2009

Kenya Bureau of Standards Mr Joel Kioko / Mr Wilson Egadwa 15 June – 5 July 2009

Ugandan National Bureau of Standards Mr Yasin Lemeriga / Mr Simon Rwashana 13 July – 2 August 2009

Tanzania Bureau of Standards Ms Edna Ndumbaro / Mr Alphonce Kagoma / Mr

Adam Ziagi

10 – 30 August 2009

NMISA 14 – 20 September 2009

National Institute of Metrology (Thailand) Mr Uthai Norranim 5 – 25 October 2009

NMISA 9 – 15 November 2009

Mauritius Standards Bureau Mr Christian Ng Ha Kwong 30 November – 20 December 2009

Seychelles Bureau of Standards - NML Mr Mamy Razanajatovo / Mr Charles Celestin 11 – 31 January 2010

NMISA 15 – 21 February 2010

SIRDC – NMI Mr Victor Mundembe 1 – 21 March 2010

Botswana Bureau of Standards Mr Keeper Morgan / Mr Tebogo Kajane 5 – 25 April 2010

INNOQ, Mozambique Mr Geraldo Albasini / Mr David Armando 10 – 30 May 2010

NMISA 14 – 20 June 2010

Malawi Bureau of Standards Mr Davlin Chokazinga 5 – 25 July 2010

Zambia Bureau of Standards Mr Fredrick Hamutunda / Mr Victor Mwazi 9 – 29 August 2010

NMISA 13 – 19 September 2010

Organisation Contact person Street address Country Telephone Fax Email

NMISA Mr Hans Liedberg Blg 6 - CSIR campus, Meiring

Naudé Road, Brummeria,

South Africa +27-12-841 2753 +27-12-841 4458 / 2131 [email protected]



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Pretoria

National Institute for

Standards

Dr. Khalid Ali Tersa St., Al Ahram, El Giza Egypt + 20-2-704 4310 +20-2-338 67451, +20-

10-579 0620

[email protected]

Quality and

Standards Authority

of Ethiopia

Mr Wondwosen

Fisseha / Ms Fitsum

Tesfaye

Bole sub city, Kebele 12/13,

near AMCE, PO Box 2310,

Addis Ababa

Ethiopia +251-11-6460 542 +251-11-6460 880 / 881 [email protected],

[email protected] /

[email protected],

[email protected]

Kenya Bureau of

Standards

Mr Joel Kioko / Mr

Wilson Egadwa

KEBS Centre, Kapiti Rd, off

Mombasa Rd, behind Bellevue

Cinema, Nairobi

Kenya +254-20-605 490 +254-20-609 660 [email protected] /

[email protected],

[email protected]

Uganda National

Bureau of Standards

Mr Yasin Lemeriga /

Mr Simon Rwashana

Plot M217, Nakawa Industrial

Area (next to Pepsi-Cola),

Kampala

Uganda +256-41-222 367 +256-41-286 123 [email protected],

[email protected] /

[email protected]

Tanzania Bureau of

Standards

Ms Edna Ndumbaro /

Mr Alphonce Kagoma

/ Mr Adam Ziagi

Morogoro / Sam Nujoma Road

– Ubungo, P.O.Box 9524, Dar-

Es-Salaam

Tanzania +255-22-245 0298 +255-22-245 0959 [email protected] /

[email protected] /

[email protected]

National Institute of

Metrology (Thailand)

Mr Uthai Norranim 3/5 Moo 3 Technopolis, Klong

V, Klong Luang, Pathumthani

12120

Thailand +662 577 5100 +662 577 5092 [email protected]

Mauritius Standards

Bureau

Mr Christian Ng Ha

Kwong

Villa Road, Moka Mauritius +230-433 3648 +230-433 5051 [email protected]

Seychelles Bureau of

Standards - NML

Mr Mamy

Razanajatovo / Mr

Charles Celestin

PO Box 953, Victoria, Mahé Seychelles +248-375 333/174

+248-380 400

+248-375 151

+248-373 826

[email protected]

SIRDC – NMI Mr Victor Mundembe

/ Mr Mathew

1574 Alpes Road, Hatcliffe,

Harare

Zimbabwe +263-4-86 0321/33,

+263-23-86 0321

+263-4-86 0350/1 [email protected] /

[email protected] /



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Ranganai [email protected] /

[email protected]

Botswana Bureau of

Standards

Mr Keeper Morgan /

Mr Tebogo Kajane

Plot 55745, Main Airport Road,

Block 8, Gaborone

Botswana +267-3903200

+267 - 3645405

+267-3903120 [email protected] /

[email protected]

INNOQ Mr Geraldo Albasini /

Mr David Armando

Av. 25 de Setembro, 1179 2

andar, Maputo

Moçambique +258-1-303 822/3 +258-1-304 206 [email protected] /

[email protected] /

[email protected]

Malawi Bureau of

Standards

Mr Davlin

Chokazinga

Moirs Road, Christwick,

Blantyre

Malawi +265 147 0488 /

+265 1 670 488

+265 167 0759 /

+265 1 670 756

[email protected]

Zambia Bureau of

Standards

Mr Fredrick

Hamutunda / Mr

Victor Mwazi

Lechwe House, Plot Number

4526, Freedom Way – South

End, Lusaka

Zambia +260-21-1-231385, cell:

+260-977 579 191,

+260-977 776 062

+260-21-1-238483 [email protected],

[email protected] /

[email protected] /

[email protected]

APPENDIX C: ARTEFACT RECEIVED

TO: NMISA

ATTN: Hans Liedberg DATE:

FAX NO: +27-12-841 2131/4458 TEL NO: +27-12-841 2753

FROM: NO OF PAGES: 1

AFRIMETS Regional Supplementary Comparison AFRIMETS.T-S1

The platinum resistance thermometers serial numbers 612, 794332, 616 and 794333

were received at ............................................................... on (date) ............................................

The condition when they were received was

mailto:[email protected]

mailto:[email protected]



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612: * in good physical and working order

* damaged (explain)


* damaged (explain)


* damaged (explain)


* damaged (explain)

Reference temperature: water triple point (0.01°C) or ice point (0.00°C) (delete whichever is not applicable)

Serial number: 612 Serial number: 794332

on local measuring instrument on travelling on local measuring instrument on travelling

Current (mA) Resistance (Ω) readout (channel A) Current (mA) Resistance (Ω) readout (channel A)

R(0.01°C) or

R(0 °C) (Ω):

R(0.01°C) or

R(0 °C) (Ω):

APPENDIX C (cntd): ARTEFACT SHIPPED

TO: NMISA


FAX NO: +27-12-841 2131/4458 TEL NO: +27-12-841 2753



The platinum resistance thermometers serial numbers 612, 794332, 616 and 794333



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were shipped to ............................................................... on (date) ............................................

The flight number / tracking number is .............................................................

..........................................................................

(name of participant)

APPENDIX D: MEASUREMENT DATA

TO: NMISA


FAX NO: +27-12-841 2131/4458 TEL NO: +27-12-841 2753



Laboratory name: ................................................................................ Metrologist: ................................................................................

Dates of measurement: .......................................... to .............................................

Thermometers measured: 612 794332 616 794333 (delete whichever are not applicable)

Reference temperature: water triple point (0.01°C) or ice point (0.00°C) (delete whichever is not applicable)


on local measuring instrument on travelling on local measuring instrument on travelling

Current (mA) Resistance (Ω) readout (channel A) Current (mA) Resistance (Ω) readout (channel A)

R(0.01°C) or

R(0 °C) (Ω):

R(0.01°C) or

R(0 °C) (Ω):

Annealing Annealing



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temperature (°C): temperature (°C):

Annealing period

(hours):

Annealing period

(hours):

R(0.01°C) or

R(0 °C) (Ω):

R(0.01°C) or

R(0 °C) (Ω):

Annealing

temperature (°C):

Annealing

temperature (°C):

Annealing period

(hours):

Annealing period

(hours):

R(0.01°C) or

R(0 °C) (Ω):

R(0.01°C) or

R(0 °C) (Ω):



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APPENDIX D (cntd): MEASUREMENT DATA

On local resistance measuring instrument: Current (mA): .............................................


Nominal

temperature (°C)

Actual

temperature (°C)

PRT

resistance (Ω)

Immersion

depth (mm)

Nominal

temperature (°C)

Actual

temperature (°C)

PRT

resistance (Ω)

Immersion

depth (mm)

0 0

70 70

140 140

200 200

250 0

330 -50

420 -20

450 -10

0 0

On channel A of travelling digital readout:


Nominal

temperature (°C)

Actual

temperature (°C)

PRT

resistance (Ω)

Immersion

depth (mm)

Nominal

temperature (°C)

Actual

temperature (°C)

PRT

resistance (Ω)

Immersion

depth (mm)

0 0

70 70

140 140



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200 200

250 0

330 -50

420 -20

450 -10

0 0



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APPENDIX E: UNCERTAINTY ANALYSIS

TO: NMISA


FAX NO: +27-12-841 2131/4458 TEL NO: +27-12-841 2753



Laboratory name: ............................................................................................

Temperature (°C): ............................................................................................

Source of uncertainty Value Unit Probability

distribution Divisor

Sensitivity

(°C / unit)

Uncertainty

contribution (k=1) (°C)

Degrees of

freedom

Calibration of reference thermometer Normal 2

Drift of reference thermometer since last

calibration

Rectangular 1.732

Stability of R(0.01°C) or R(0°C): ref thermometer

(if it is a PRT)

Rectangular 1.732

Uncertainty of reference temperature (water

triple point or ice point): ref thermometer


ref thermometer

Temperature gradient in bath / furnace (including

stem conduction error)

Rectangular 1.732



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Stability of R(0.01°C) or R(0°C): UUT

Uncertainty of reference temperature (water

triple point or ice point): UUT


UUT

Repeatability Normal 1

Other (please specify)

Combined uncertainty (k=1): X X X X

APPENDIX F: DETAILS OF INSTRUMENTATION USED IN THE COMPARISON

TO: NMISA


FAX NO: +27-12-841 2131/4458 TEL NO: +27-12-841 2753



Laboratory name: ............................................................................................

Local resistance measuring instrument: Type: ........................................ Manufacturer: ........................................ Model: ........................................

Note: Instrument type = AC resistance bridge (specify frequency, if known), DC resistance bridge, digital multimeter, etc

Nominal Reference thermometer Heat source

temperature (°C) Type Manufacturer Model S/N Type Manufacturer Model



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-50

-20

-10

0

70

140

200

250

330

420

450

Note: Reference thermometer type = standard PRT (SPRT), industrial PRT (IPRT), type R thermocouple, etc (or none, if ice point is used as temperature reference).

Heat source type = stirred liquid bath, fluidised bath, ice point, horizontal tube furnace, etc. If tube furnace is used, please specify if it is used with or without a

thermal equalising block.



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APPENDIX 2: INSTRUMENTATION

NMISA:

Local resistance measuring instrument: Type: AC resistance bridge (25 Hz) Manufacturer: ASL Model: F18



-50 SPRT Leeds & Northrup 8167-25 1827488 stirred liquid bath Heto CB217



0 WTP cell Jarrett or Hart A11 or 5901A 2035, 2048 or 1181

70 SPRT Leeds & Northrup 8167-25 1827488 stirred liquid bath Isotech 915



250 SPRT Tinsley 5187SA 269581 stirred liquid bath Heto JH02




NIS:

Local resistance measuring instrument: Type: AC resistance bridge (75 Hz) Manufacturer: Tinsley Model: Senator



-50 SPRT Fluke 5628 1748 stirred liquid bath Fluke Hart Scientific 7381



0 SPRT Fluke 5628 1748 Ice bath Home made --



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70 SPRT Fluke 5628 1748 stirred liquid bath ISOTECH NIXON 815M

140 SPRT Fluke 5628 1748 stirred liquid bath Fluke Hart Scientific 6054








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QSAE (NMIE):

Local resistance measuring instrument: Type: Resistance bridge Manufacturer: Hart Scientific Model: Super thermometer



-50 SPRT H. TINSLEY 5187 S.A. 250236 Stirred Alcohol bath LAUDA, Germany RLS6



0 SPRT H. TINSLEY 5187 S.A. 250236 Ice point - 4000ml

70 SPRT H. TINSLEY 5187 S.A. 250236 Stirred Water bath LAUDA, Germany CSD30

140 SPRT H. TINSLEY 5187 S.A. 250236 Stirred Oil bath LAUDA, Germany R 400

200 SPRT H. TINSLEY 5187 S.A. 250236 Stirred Oil bath LAUDA, Germany R 400

250 SPRT H. TINSLEY 5187 S.A. 250236 Fluidised bath Techne, England FB-08




KEBS:

Local res meas

instrum: Type: DIGITAL MULTIMETER Manufacturer: ANTON PAAR Model: UUT: MKT100, ref std: MKT25



-10 SPRT Isotech 909L/909Q 1415/1561 Alcohol Bath with equalising

block

Mgw Lauda UK 80

DK

0 SPRT Isotech 909L/909Q 1415/1561 Ice Bath Isotherm -



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70 SPRT Isotech 909L/909Q 1415/1561 Water Bath Tamson TV 7000

140 SPRT Isotech 909L/909Q 1415/1561 Oil Bath with equalising

block

Tamson TV 5000

200 SPRT Isotech 909L/909Q 1415/1561 Oil Bath with equalising

block

Tamson TV 5000

250 SPRT Isotech 909L/909Q 1415/1561 Sand Bath with equalising

block

Isotech Ayries


block

Isotech Ayries


block

Isotech Ayries


block

Isotech Ayries

NIMT:

Local resistance measuring instrument: Type: Resistance bridge Manufacturer: Hart Scientific Model: Super thermometer



-50 SPRT H. Tinsley 5187SA 280419 stirred liquid bath FLUKE 7381



0 SPRT H. Tinsley 5187SA 280419 stirred liquid bath FLUKE 7381

70 SPRT Hart Scientific 5681 1522 stirred liquid bath FLUKE 6331




330 SPRT ISOTECH 935-14-77 43 stirred liquid bath Hart Scientific 6055



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MSB:

Local resistance measuring instrument: Type: DC resistance meter Manufacturer: Isotech Model: TTI22



-50

-20 SPRT Isotech 670SH 029 metal block bath Isotech Oceanus 580

-10 SPRT Isotech 670SH 029 metal block bath Isotech Oceanus 580

0 SPRT Isotech 670SH 029 ice point

70 SPRT Isotech 670SH 029 stirred liquid bath Heto KB22-1

140 SPRT Isotech 670SH 029 stirred liquid bath Heto KB12-1

200 SPRT Isotech 670SH 029 metal block bath Isotech Medusa 510







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APPENDIX 3: UNCERTAINTY BUDGETS

NMISA:

Temperature (°C): 0 °C, UUT (612)

Source of uncertainty Value Unit Probability Divisor Sensitivity Uncertainty Degrees of

distribution (°C / unit) contribution (k=1) (°C) freedom

Calibration of reference thermometer 0.00005 °C Normal 1 1 0.0001 500

Drift of reference thermometer since last cal

Stability of R(0.01°C) or R(0°C): ref thermometer (if it is a PRT)

Uncert of ref temperature (WTP or ice point): ref thermometer

Uncert of electrical measuring instrument: ref thermometer

Temp gradient in bath/furnace (incl stem conduction error) 0.00008 °C Rectangular 1.732050808 1 0.0000 500


Uncert of ref temperature (WTP or ice point): UUT

Uncert of electrical measuring instrument: UUT 2.E-07 Ω/Ω Normal 2 250.712356 0.0000 41

Repeatability

Temp coeff of ref resistor 0.2 °C Rectangular 1.732050808 -0.0001254 0.0000 500

Combined uncertainty (k=1): X X X X 0.0001

Expanded uncertainty (k=2) (°C): 0.0002





Drift of reference thermometer since last cal 0.00120 °C Rectangular 1.732050808 1 0.0007 500

Stability of R(0.01°C) or R(0°C): ref thermometer (if it is a PRT) 0.00002 °C Rectangular 1.732050808 1.19830661 0.0000 500



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Uncert of ref temperature (WTP or ice point): ref thermometer 0.00030 °C Normal 2 1.19830661 0.0002 500

Uncert of electrical measuring instrument: ref thermometer 2.E-07 Ω/Ω Normal 2 996.301017 0.0001 41


Stability of R(0.01°C) or R(0°C): UUT 0.00045 °C Rectangular 1.732050808 1.19830661 0.0003 500

Uncert of ref temperature (WTP or ice point): UUT 0.00015 °C Normal 2 1.19830661 0.0001 500


Repeatability 0.00030 °C Normal 1 1 0.0003 2






















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Drift of reference thermometer since last cal

Stability of R(0.01°C) or R(0°C): ref thermometer (if it is a PRT)

Uncert of ref temperature (WTP or ice point): ref thermometer

Uncert of electrical measuring instrument: ref thermometer



Uncert of ref temperature (WTP or ice point): UUT


Repeatability

Temp coeff of ref resistor 0.2 °C Rectangular 1.732050808 -0.0001254 0.0000 500



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Temperature (°C): -50 °C, UUT (794332)




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NIS:




Calibration of reference thermometer 0.0025 °C Normal 2 1 0.0013 ∞



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Drift of reference thermometer since last cal 0.0002 °C Rectangular 1.732 1 0.0001 ∞

Stability of R(0.01°C) or R(0°C): ref thermometer (if it is a PRT) -0.00003 ohm Rectangular 1.732 11.6 -0.0001 ∞

Uncert of ref temperature (WTP or ice point): ref thermometer 0.0002 °C Rectangular 1.732 1 0.0001 ∞

Uncert of electrical measuring instrument: ref thermometer 1 ppm ohm Rectangular 1.732 11.6 0.0007 ∞

Temp gradient in bath/furnace (incl stem conduction error) 0.003 °C Rectangular 1.732 1 0.0009 ∞

Stability of R(0.01°C) or R(0°C): UUT 0.001 ohm Rectangular 1.732 2.5 0.0007 ∞

Uncert of ref temperature (WTP or ice point): UUT 0.0002 °C Rectangular 1.732 1 0.0001 ∞

Uncert of electrical measuring instrument: UUT 0.005 °C Rectangular 1.732 2.5 0.0020 ∞









Drift of reference thermometer since last cal -0.0002 °C Rectangular 1.732 1 -0.0001 ∞












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Uncert of ref temperature (WTP or ice point): ref thermometer 0.0002 °C Rectangular 1.732 0.0002 ∞




















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Uncert of ref temperature (WTP or ice point): UUT 0.0002 °C Rectangular 1.732 0.0003 ∞




















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Calibration of reference thermometer 0.003 Normal 2 0.0013 ∞





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Stability of R(0.01°C) or R(0°C): UUT 0 ohm Rectangular 1.732 2.5 0.0000 ∞









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Calibration of reference thermometer 0.0025 Normal 2 0.0013 ∞









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Drift of reference thermometer since last cal 0.0002 °C Rectangular 1.732 1 0.0001 ∞








Repeatability 0.0014 °C Normal 1 0.0014 5










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Repeatability 0.0014 °C Normal 1 0.0014 5




















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QSAE (NMIE):




Calibration of reference thermometer 8.5 mK Normal 2 0.001 0.0043 ∞

Drift of reference thermometer since last cal 0 mK Rectangular 1.732 0.001 0.0000

Stability of R(0.01°C) or R(0°C): ref thermometer (if it is a PRT) 0.00056227 oC Rectangular 1.732 1 0.0003

Uncert of ref temperature (WTP or ice point): ref thermometer 0.00249991 oC Rectangular 1.732 1 0.0014

Uncert of electrical measuring instrument: ref thermometer 1.0106E-05 oC Normal 2 1 0.0000 ∞

Temp gradient in bath/furnace (incl stem conduction error) 0.02 oC Rectangular 1.732 1 0.0115

Stability of R(0.01°C) or R(0°C): UUT -0.0003266 oC Rectangular 1.732 1 -0.0002

Uncert of ref temperature (WTP or ice point): UUT 0.0024999 oC Rectangular 1.732 1 0.0014

Uncert of electrical measuring instrument: UUT 2.5595E-06 oC Normal 2 1 0.0000 ∞

Repeatability 0.00020299 oC Normal 1 1 0.0002 9

Self-heating: UUT 0.00767856 oC Rectangular 1.732 1 0.0044

Combined uncertainty (k=1): oC Normal 1 0.0132






Drift of reference thermometer since last cal 0.1 mK Rectangular 1.732 0.001 0.0001




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Repeatability 8.6705E-05 oC Normal 1 1 0.0001 9


Combined uncertainty (k=1): X X Normal 1 0.0189






Drift of reference thermometer since last cal -0.1 mK Rectangular 1.732 0.001 -0.0001














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Calibration of reference thermometer 14 mK Normal 2 0.001 0.0070 ∞



















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Drift of reference thermometer since last cal 0 mK Rectangular 1.732 0.001 0.0000

Stability of R(0.01°C) or R(0°C): ref thermometer (if it is a PRT) -9.926E-05 oC Rectangular 1.732 1 -0.0001









Combined uncertainty (k=1): oC Normal 1 0.0132







Stability of R(0.01°C) or R(0°C): ref thermometer (if it is a PRT) -0.0001001 oC Rectangular 1.732 1 -0.0001





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Stability of R(0.01°C) or R(0°C): ref thermometer (if it is a PRT) -7.877E-05 oC Rectangular 1.732 1 0.0000
















Stability of R(0.01°C) or R(0°C): ref thermometer (if it is a PRT) -9.155E-05 oC Rectangular 1.732 1 -0.0001



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KEBS:




Calibration of reference thermometer 1.50E-02 ºC Normal 2 1 0.0075 20

Drift of reference thermometer since last cal 6.96E-04 Ω Rectangular 1.73205081 9.8 0.0039 ∞

Stability of R(0.01°C) or R(0°C): ref thermometer (if it is a PRT) 0.00173 Ω Rectangular 1.73205081 9.8 0.0098 50

Uncert of ref temperature (WTP or ice point): ref thermometer 0.02 ºC Rectangular 1.73205081 1 0.0115 100

Uncert of electrical measuring instrument: ref thermometer 0.00148157 Ω Normal 2 9.8 0.0073 20

Temp gradient in bath/furnace (incl stem conduction error) 0.00055 ºC Rectangular 1.73205081 1 0.0003 20

Stability of R(0.01°C) or R(0°C): UUT 0.00148 Ω Rectangular 1.73205081 2.5 0.0021 50

Uncert of ref temperature (WTP or ice point): UUT 0.02 ºC Rectangular 1.73205081 1 0.0115 50

Uncert of electrical measuring instrument: UUT 0.025 ºC Rectangular 1.73205081 1 0.0144 ∞

Repeatability 0.00E+00 Ω Normal 1 2.5 0.0000 20

Self-heating: UUT 0.00032 Ω Normal 1.73205081 2.5 0.0005 50



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Combined uncertainty (k=1): 0.0265








Uncert of ref temperature (WTP or ice point): ref thermometer 0.0017 ºC Rectangular 1.73205081 9.8 0.0123 100



Stability of R(0.01°C) or R(0°C): UUT -0.008 Ω Rectangular 1.73205081 2.5 -0.0147 50



Repeatability 2.34E-04 Ω Normal 1 2.5 0.0006 20














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Uncert of electrical measuring instrument: UUT 2.50E-02 ºC Normal 2 1 0.0125 ∞















Uncert of ref temperature (WTP or ice point): UUT -0.004185 ºC Rectangular 1.73205081 2.5 -0.0060 50

Uncert of electrical measuring instrument: UUT 0.025 ºC Normal 2 1 0.0125 ∞









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Temp gradient in bath/furnace (incl stem conduction error) -0.0352925 ºC Rectangular 1.73205081 1 -0.0204 20



Uncert of electrical measuring instrument: UUT 2.50E-02 ºC Normal 1.73205081 1 0.0144 ∞
















Uncert of electrical measuring instrument: UUT 5.50E-02 ºC Normal 1.73205081 1 0.0318 ∞



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Uncert of electrical measuring instrument: UUT 0.045 ºC Normal 1.73205081 1 0.0260 ∞













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Uncert of electrical measuring instrument: UUT 0.045 ºC Normal 2 2.5 0.0563 ∞























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Uncert of electrical measuring instrument: UUT 2.50E-02 ºC Normal 2 1 0.0125 ∞



























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Uncert of electrical measuring instrument: UUT 0.025 ºC Normal 1.73205081 1 0.0144 ∞





NIMT:




Curve fit residuals: UUT 0.00007 Ω normal 1 2.6 0.0002 26

Repeatability: UUT 0.0001 Ω normal 1 2.6 0.0003 26

Repeatability: ref thermometer 0.00024 °C normal 1 1 0.0002 26

Calibration of reference thermometer 0.001 °C normal 2 1 0.0005 ∞

Drift of reference thermometer since last cal 0.005 °C rectangular SQRT(3) 1 0.0029 ∞

Uncert of electrical measuring instrument 0.0003 Ω normal 2 2.6 0.0004 ∞

Drift of electrical measuring instrument 0.001 Ω rectangular SQRT(3) 2.6 0.0015 ∞

Stability of R(0.01°C) or R(0°C): UUT 0.00179 Ω rectangular 2SQRT(3) 2.6 0.0013 ∞

Temp gradient in bath/furnace (incl stem conduction error) 0.001 °C rectangular SQRT(3) 1 0.0006 ∞



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Instability of bath 0.003 °C rectangular SQRT(3) 1 0.0017 ∞

Interpolation function 0.00417 Ω rectangular SQRT(3) 2.6 0.0061 ∞

Combined uncertainty (k=1): normal 0.0070


























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UNBS:







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Uncert of ref temperature (WTP or ice point): ref thermometer 0.012473 Ω Rectangular 1.732050808 2.56 0.0184 100




Uncert of ref temperature (WTP or ice point): UUT 0.00095 Ω Rectangular 1.73205081 2.56 0.0014 50



Ambient conditions 0.01 Ω Normal 2 2.56 0.0128 50



















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Uncert of ref temperature (WTP or ice point): UUT 0.015 ºC Rectangular 1.73205081 2.548 0.0221 50








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Uncert of ref temperature (WTP or ice point): UUT 0.015 ºC Rectangular 1.73205081 2.548 0.0221 50






TBS:




Calibration of reference thermometer 0.005 ºC Normal 2 1 0.0025

Drift of reference thermometer since last cal 0.005 ºC Rectangular 1.732 1 0.0029 ∞

Stability of R(0.01°C) or R(0°C): ref thermometer (if it is a PRT) 0.0005 Ω Rectangular 1.732 0.1011 0.0000 ∞

Uncert of ref temperature (WTP or ice point): ref thermometer 0.01 ºC Normal 2 1 0.0050 ∞

Uncert of electrical measuring instrument: ref thermometer 0.002 Ω Normal 2 2.5641 0.0026 ∞



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Temp gradient in bath/furnace (incl stem conduction error) 0.029 ºC Rectangular 1.732 1 0.0167 ∞


Uncert of ref temperature (WTP or ice point): UUT 0.01 ºC Rectangular 1.732 1 0.0058

Uncert of electrical measuring instrument: UUT 0 0.0000

Repeatability 0.0065 ºC Normal 1 1 0.0065
























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MSB:



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Stability of R(0.01°C) or R(0°C): ref thermometer (if it is a PRT) 0.029 °C Rectangular 1.732050808 1 0.0167 200

Uncert of ref temperature (WTP or ice point): ref thermometer 0.006 °C Normal 2 1 0.0030 200

Uncert of electrical measuring instrument: ref thermometer 0.001 °C Rectangular 1.732050808 1 0.0006 200


Stability of R(0.01°C) or R(0°C): UUT 200

Uncert of ref temperature (WTP or ice point): UUT 200

Uncert of electrical measuring instrument: UUT 200

Repeatability 0.000289 °C Rectangular 1.732050808 1 0.0002 200
















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Source of uncertainty distribution (°C / unit) contribution (k=1) (°C) freedom

0.01 °C Normal 2 1 0.0050 200



















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Temp gradient in bath/furnace (incl stem conduction error) 0 °C Rectangular 1.732050808 1 0.0000 200






















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REPORT ON AFRIMETS SUPPLEMENTARY COMPARISON: … · IPRT comparison (-50 °C to 450 °C)...

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Transcript of REPORT ON AFRIMETS SUPPLEMENTARY COMPARISON: … · IPRT comparison (-50 °C to 450 °C)...