FLUKE 5700A/5720A ARTIFACT CALIBRATION

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FLUKE 5700A/5720AARTIFACT CALIBRATION

• MAC Study Group
• R.Kletke, D.Deaver, B.Sorrells, M.Duffin, S.
  Dizor

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PURPOSE OF STUDY

• A2LA presently accepts Flukes claim for
  specifications based on the calibration cycle of
  its artifact calibration, provided the instrument
  is given a classical external calibration at
  least bi-annually. The task groups intent is to
  determine what should be done, if anything, to
  help verify those claims and to determine any
  contingencies that may be involved.

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Artifact Calibration

• The Fluke 5700A/5720A makes use of internal check
  standards and measurement systems so it can be
  completely calibrated in place to full
  specifications using a small number of convenient
  portable standards
• (Operations Manual, Paragraph 1-15, p 1-8)

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5700A/5720A with ARTIFACT CAL.
10 V DC Standard
6.5 V DC Reference.
26 Bit DAC
Calibrator Circuitry
13 V DC Reference
Switching Matrix
1 Ohm Standard
1 Ohm Reference
Multi-Range TVC Standard 1kHz -1MHz
10 kOhm Standard
1.9 Ohm Reference
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IMPORTANT OBSERVATIONS

• Works well for DCV, DCI and R with unbroken
  traceability chain
• No traceability for AC parameters with Artifact
  Cal
• Does adjust calibrator within the 24 hour
  specification for all parameters provided TVC
  standard remains stable
• Cal Shift Report accurately reflects adjustment
  changes

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PROBLEMS

• IF AC traceability is established by initial
  overall calibration, then artifact calibration
  during the cal period breaks traceability
• Measurement values and uncertainties are not
  given on the Cal Shift Report

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SOLUTIONS

• AC traceability and measurement values can be
  established from the artifact calibration Cal
  Shift report.
• Measurement uncertainties are bounded by the
  calibrator 24 hour specification

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RECOMMENDATIONS BY EU NATIONAL LAB STUDY

• The Artifact Cal report, complete with shift data
  for all parameters, should be examined and stored
  by the user
• The user of an instrument should be able to
  justify the calibration interval he has chosen
• Full calibrations should be made at least every
  two years

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CALIBRATION RECIPE GUIDELINE
EA 1 year CAC CAC CAC CAC CAC CAC
Fluke 1 year AC A AC A AC A
Study 1 year AC AC A AC A AC
Study 90 Day AC AC A AC A A A AC A A A A A A A AC A A A A A
0 3m 6m 9m 1yr 3m 6m 9m 2yr 3m 6m 9m 3yr 3m 6m 9m 4yr 3m 6m 9m 5yr
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MAC WORKGROUP RECOMMENDATIONS

• Accept EU National Lab study with recommendations
• Schedule Complete Cal and Artifact Cal so that
  performance at the desired cal interval is
  confirmed by the As Found data collected during
  Complete Cal. This should be repeated at every
  Complete Cal.

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WORKGROUP CAL GUIDELINE
CAL PERIOD
12 Mo AC AC A AC
6 Mo AC A AC A A A AC
3 Mo AC A A A AC A A A A A A A AC
Mo 0 3 6 9 12 15 18 21 24 27 30 33 36
Yr 0 1 2 36
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ARTIFACT CAL SHIFT REPORTSample Page
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Concluding Remarks

• Collect, review and store Cal Shift report after
  every Art Cal. Verify cal shifts do not exceed
  claims
• Take care during Art Cal to set 5700A/5720A to
  proper specifications
• If User claims Fluke 99 CL specs, cal shift
  limit on report is 100
• If User claims Fluke 95 CL specs, cal shift
  limit on report is 77
• Take care that As Found data collected during
  full calibration is checked against the
  performance claimed by Art Cal period.