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Evaluation of measurement results in testing laboratories Gaber Begeš Laboratory of Metrology and Quality Faculty of Electrical Engineering University of Ljubljana INCOLAB, Prague 2003. INTRODUCTION. 1. Introduction to testing 2. Anal ysis and calculation of measurement
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Evaluation of measurement results • in testing laboratories • Gaber Begeš • Laboratory of Metrology and Quality • Faculty of Electrical Engineering • University of Ljubljana • INCOLAB, Prague 2003
INTRODUCTION 1. Introduction to testing 2. Analysisandcalculation of measurement uncertainty in testing 3. Traceabilty of measurements in testing
What is testing? Action of carrying out one or more technical operation that consists of the determination of one or more characteristics of a given product, proces or service according to a specified procedure. (General vocabulary SIST EN 45020)
PROTECTION OF CONSUMERS WHY ? testing traceability measurement uncertainty
Producer bankrupts Producer SOLUTION IS QUALITY SYSTEM Non- conformable Double damage for producer complaints Buy, use the appliance Appliance burns and damage the surroundings WHYtesting, measurement uncertainty
why • measurement • uncertainty is not • taken into account WHYtesting andmesurement uncertainty - ignorance of user manual - faulty appliance - …...
Measurement Equipment ISO 10012-1 TESTING ISO 9001 Quality Systems SIST EN ISO/IEC 17025 General requirements for the competence of testing and calibration laboratories • ESTIMATION OF MEASUREMENT UNCERTAINTY • TRACEABILITY OF MEASUREMENT Testing and standards
Verification Testing Calibration Metrology Measurement uncertainty Traceability
2. MEASUREMENT UNCERTAINTY IN TESTING
1 Calculation of measurement uncertainty (Non-correlated quantities) - measuring of quantities, with no functional correlation f(x1) g(x2) h(xN), u1= f(x1), u2= g(x2), ..., uN= h(xN), - indirect measured quantities y = f(x1, x2, …, xN) - direct measured quantities
2 Calculation of measurement uncertainty u2a= f(l) u2b= f(l) u3= f(m) u(m) ust(m) u(l) ust(l) u4= f(I) u(I) ust(I) u1= f(T) u(T) ust(T) Measured quantities do not have functional correlation Glow-wire test
3 Calculation of measurement uncertainty Power u1=f(I) measurement. u2=f(U) j cos u3=f(cos) 3 A U Test sample V 0
3 Calculation of measurement uncertainty - calibration method and used calibration equipment - calibration method and used calibration equipment - module for data acquisition - module for data acquisition - type of thetmocouples - type of thetmocouple - uncertainty of thermocouples - uncertainty of thermocouples - cold junction of thermocouples - cold junction of thermocouple - color of the black test corner - distance between thermocouples - environmental temperature Testing of heating of appliance - contribution of the tested appliance - influence of personnel Measurement uncertainty of a measurement system depends on:
T U D T = f(standard) ’ D T = f(U) M A X M A X T =f(room temperature) 0 t How to take into consideration the measurement uncertainty
How to take into consideration the measurement uncertainty 2 1 Upper limit Lower limit X 1 example A 2 2 1 1 example B X X' 2 2 2 2 1 1 example C X X' 3 3 2 2 1 1 example D X' X 4 Range of conformity 4
costs Production costs Measurement costs Total costs Minimum total costs measurement uncertainty How to take into consideration the measurement uncertainty
3. TRACEABILITY OF MEASUREMENT
reference calibration of reference standard standard LMK calibrated in fixed points Laboratory of Metrology and Quality (SI unit) calibration of LMK thermocouples Laboratory of Metrology and Quality traceability to SI unit . . . Testing of heating Traceability of measurement
SI units LMK PTB NMi, PTB PTB calibration of reference instrument SIQ LMK LTM Laboratorijski center Slovenski inštitut Laboratorij za Laboratorij za Ljubljana, za kakovost in metrologijo in tehnološke meritve Laboratorij za maso meroslovje kakovost calibration of thermocouple Calibration of ampermeter Calibration of measuring tool Calibration of mass glow wire test Traceability of measurement
SI units NMi PTB NMi, PTB calibration of reference standards SIQ SIQ SIQ Calibration of ampermeter Calibration of voltmeter Calibration of cos- meter j power ufI =() measurement 1 ufU =() j j cos 2 uf =(cos) 3 A Test appliance U V 0 Traceability of measurement
Traceability of measurement + implemented QUALITY SYSTEM proved qualification, capability of measuring, consideration of measurement uncertainty
Why testing? • Testing and Metrology verification testing calibration Metrology Measurement uncertainty Traceability • Calculation of the Measurement uncertainty • Consideration of the measurement result • Traceability of the measurement result Conclusion
Happiness Safety Customer Effectiveness of producers Conclusion