Comparison
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Results

CCEM-K2, SIM.EM-K2, EUROMET.EM-K2 and EURAMET.EM-K2.1

MEASURAND : Resistance
NOMINAL VALUE : 1 gigaohm

Degrees of equivalence, Di and expanded uncertainty Ui (k = 2), relative to the CCEM-K2 key comparison reference value, expressed in 10-6

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Comparison
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Results

CCEM-K2, SIM.EM-K2, EUROMET.EM-K2 and EURAMET.EM-K2.1

MEASURAND : Resistance
NOMINAL VALUE : 1 gigaohm

Degrees of equivalence, Di and expanded uncertainty Ui (k = 2), relative to the CCEM-K2 key comparison reference value, expressed in 10-6

Black: participants in CCEM-K2
Green: participants in SIM.EM-K2 only
Blue: participants in EUROMET.EM-K2 only
Orange: participants in EURAMET.EM-K2.1 only

The Matrix of equivalence reproduced below is limited to the degrees of equivalence of the CCEM-K2 and SIM.EM-K2 participants.

   
Lab iDiUi
/ 10-6/ 10-6
NIST-0.18.6
NRC-0.219.8
LNE-1.318.0
NPL-7.211.0
PTB3.313.0
NMIA2.166.8
MSL4.66.6
NMISA-53581
SP-1.610.0
METAS2.922.8
INRIM2.519.3
VSL-32.336.3
KRISS-1.512.4
NIM-0.68.3
VNIIM0.07.3
INTI-7.512.6
INMETRO-4.211.8
UTE-4.335.5
CENAM3.716.0

Results are presented under A4 printable format in Summary Results (PDF file). This includes the full Matrix of equivalence for CCEM-K2, SIM.EM-K2 and EUROMET.EM-K2.

Comparison
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RMO comparison
Linked comparison
SIM.EM-K2
Metrology area, Sub-field Electricity and Magnetism, Resistance
Description Comparison of resistance standards
Time of measurements 2006 - 2007
Status Approved for equivalence
Final Reports of the comparisons
Measurand Resistance: 1 gigaohm
Transfer device Wirewound and film-type resistors
Comparison type Key Comparison
Consultative Committee CCEM (Consultative Committee for Electricity and Magnetism)
Conducted by SIM (Inter-American Metrology System)
Comments

 

 

Results published on 14 January 2009

SIM.EM-K2, EUROMET.EM-K2 and EURAMET.EM-K2.1 results are linked to those of CCEM-K2

Resistance

 

 

Pilot institute NIST
National Institute of Standards and Technology
United States
Contact person R. Elmquist

+1 301 975 6591
Additional
First Name Last Name
wwww@ww.www +356719836 Institute 1 Institute 1 Khmelnitskiy
Pilot laboratory
NIST

National Institute of Standards and Technology, United States, SIM

CENAM

Centro Nacional de Metrologia, Mexico, SIM

INMETRO

Instituto Nacional de Metrologia, Qualidade e Tecnologia, Brazil, SIM

INTI

Instituto Nacional de Tecnologia Industrial, Argentina, SIM

NRC

National Research Council, Canada, SIM

UTE

Administración Nacional de Usinas y Transmisiones Eléctricas, Uruguay, SIM

Comparison
Comparison close
Results

CCEM-K2, SIM.EM-K2, EUROMET.EM-K2 and EURAMET.EM-K2.1

MEASURAND : Resistance
NOMINAL VALUE : 1 gigaohm

  • Key comparison CCEM-K2

The key comparison reference value is obtained from the weighted average of the DiCOMB's and is xR = 0.10x10-6.
The expanded uncertainty (k = 2) of xR is UR = 3.19x10-6.

The degree of equivalence of each laboratory with respect to the reference value is given by a pair of terms:
Di = DiCOMB - xR and its expanded uncertainty (k = 2), Ui = (UiCOMB2 - UR2)1/2.

The degree of equivalence between two laboratories i and j is given by a pair of terms:
Dij = Di - Dj and its expanded uncertainty (k = 2), Uij which calculation is described in detail in the CCEM-K2 Final Report.
  • Key comparison SIM.EM-K2

The procedure for analysing the results of SIM.EM-K2 is explained in the Appendix A of the SIM.EM-K2 Final Report.
A SIM.EM-K2 reference value and its uncertainty are first computed using results obtained in this key comparison. Degrees of equivalence of each participating laboratory with respect to the SIM.EM-K2 reference value, as well as pair-wise degrees of equivalence, are then computed.

  • Linking SIM.EM-K2 to CCEM-K2

The linkage of SIM.EM-K2 results to those of CCEM-K2 is ensured by the common participation of NIST and NRC in both comparisons. The detailed calculation of the linkage is explained in Appendix G of the SIM.EM-K2 Final Report.

  • Key comparison EUROMET.EM-K2

The procedure for analysing the results of EUROMET.EM-K2 is explained in Section 6.4 on page 17 of the EUROMET.EM-K2 Final Report.
An EUROMET.EM-K2 reference value and its uncertainty are first computed using results obtained in this key comparison. Degrees of equivalence of each participating laboratory with respect to the EUROMET.EM-K2 reference value, as well as pair-wise degrees of equivalence, are then computed.

  • Linking EUROMET.EM-K2 to CCEM-K2

The linkage of EUROMET.EM-K2 results to those of CCEM-K2 is ensured by the common participation of METAS, PTB, VSL, NPL, LNE and VNIIM in both comparisons. The detailed calculation of the linkage is explained in Section 6.6 on page 31 of the Final Report.

  • Linking EURAMET.EM-K2.1 to CCEM-K2

The results of EURAMET.EM-K2.1 are first linked to the EUROMET.EM-K2 reference value through the results of METAS, and then linked to the CCEM-K2 key comparison reference value as done for the EUROMET.EM-K2 results (see Sections 6.3 and 6.4 of the EURAMET.EM-K2.1 Final Report).

This makes it possible to extend the CCEM-K2 degrees of equivalence to those laboratories which participated in key comparisons SIM.EM-K2, EUROMET.EM-K2 and EURAMET.EM-K2.1 only.

No pair-wise degrees of equivalence involving EURAMET.EM-K2.1 participants have been computed.

Comparison
Comparison close
Results

CCEM-K2, SIM.EM-K2, EUROMET.EM-K2 and EURAMET.EM-K2.1

  • Key comparison CCEM-K2

MEASURAND : Resistance
NOMINAL VALUE : 1 gigaohm

xi : result of measurement carried out by laboratory i, expressed as the relative deviation from the nominal value R0 = 1 gigaohm, namely Ri = R0(1 + xi) where Ri is the resistance measured by laboratory i.
The xi's are corrected to a nominal temperature of 23 °C
Ui : expanded uncertainty (k = 2) of xi
S/N : serial number of the travelling standard
DiCOMB : combined mean of the three travelling standards relative differences from a least-squares linear regression of the NIST values for each travelling standard
UiCOMB : expanded uncertainty (k = 2) of DiCOMB

The calculation of the DiCOMB's and UiCOMB's is described in detail in the Final Report.

* Measurements at 91 V
** Measurements at 50 V
All other measurements at 100 V

  • Key comparison SIM.EM-K2

MEASURAND : Resistance
NOMINAL VALUE : 1 gigaohm

Individual measurements reported by laboratories participant in SIM.EM-K2 are given in Tables 6.5 and 6.6 for both of the transfer instruments: see on pages 17 and 18 of the SIM.EM-K2 Final Report. These are relative difference between the result of measurement of laboratory i and the nominal value 1 gigaohm.
Measurements were carried out between January 2006 and August 2007.

  • Key comparison EUROMET.EM-K2

MEASURAND : Resistance
NOMINAL VALUE : 1 gigaohm

Individual measurements and uncertainties reported by laboratories participant in EUROMET.EM-K2 are given in the Annexes of the EUROMET.EM-K2 Final Report.
LATMB (Latvia) did not measure at nominal value 1 gigaohm.
Measurements were carried out between August 2005 and April 2007.

  • Key comparison EURAMET.EM-K2.1

MEASURAND : Resistance
NOMINAL VALUE : 1 gigaohm

Individual measurements and uncertainties reported by laboratories participant in EURAMET.EM-K2.1 are given in the Annexes of the EURAMET.EM-K2.1 Final Report.
Measurements were carried out between March 2010 and February 2011.