1. NCSLI 2013 Conference 1 How to Achieve a 0.01 µV/V Deviation on Your 10 Vdc Proficiency Test Without using a Josephson Array Author:Gary Bennett – National Instruments Metrology Laboratory Manager Speaker: Jorge Martins – National Instruments Principal Metrology Engineer

2. NCSLI 2013 Conference 2 Learning Objectives Activities required to maintain a 10 Vdc reference standard Tools available to make precision 10 Vdc transfer measurements Overview of techniques to track measured values and project future values of precision standards

3. NCSLI 2013 Conference 3 Opportunity for Internal Support Need to perform artifact calibrations on Fluke 5720A to maintain the 90 day specifications Purchased: – 4x 10 Vdc Reference Standards –Data Proof VoltRef SW and 160B scanner –Nanovoltmeter

4. NCSLI 2013 Conference 4 Requirements 10 Vdc uncertainty for calibrator adjustment is: ±1.5 µV/V 10 Vdc Reference Stability Specification

5. NCSLI 2013 Conference 5 Options Expand the 90 day specification of the 57x0 as per mfg. manual Shorten interval of 10 Vdc Zener references Buy a 10 Vdc with history … that you can trust! Devise a process to expedite the characterization of our Zener References

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8. 8 Our Chosen Method Calibrate all 4 using MAP program after six months. –Measure the travelling standard Create procedure to measure the travelling standard Review the previous 6 months of VoltRef data Determine uncertainty –Measure all our 10 Vdc references against the travelling standard using the MAP provider’s procedure

9. NCSLI 2013 Conference 9 Measurements Prior to 2 nd Calibration

10. NCSLI 2013 Conference 10 Result of 1 st Proficiency Test

11. NCSLI 2013 Conference 11 What Happened?

12. NCSLI 2013 Conference 12 2 nd Calibration

13. NCSLI 2013 Conference 13 2 nd Calibration Results

14. NCSLI 2013 Conference 14 3 rd Calibration 2 nd Proficiency Test

15. NCSLI 2013 Conference 15 3 rd Calibration, 2 nd Proficiency Test

16. NCSLI 2013 Conference 16 Proficiency Test #2

17. NCSLI 2013 Conference 17 Projected Values and 3 rd Calibration

18. NCSLI 2013 Conference 18 3 rd Calibration

19. NCSLI 2013 Conference 19 Proficiency Test #3

20. NCSLI 2013 Conference 20 4 th Calibration

21. NCSLI 2013 Conference 21 Proficiency Test #4

22. NCSLI 2013 Conference 22 5 th Calibration

23. NCSLI 2013 Conference 23 5 th Calibration Cell #1

24. NCSLI 2013 Conference 24 Uncertainty Components Calibration Uncertainty (Travelling standard) Atmospheric Pressure Temperature Noise Type A Statistical Uncertainty of Projected Value Hysteresis Error

25. NCSLI 2013 Conference 25 Conclusion VoltRef works very well with the proper drift information for each cell Tools are available to make the data gathering less painful Understanding the normal differences in performance of individual references is important Gathering history on reference standards is expensive

26. NCSLI 2013 Conference 26 Questions