Traceability

Measuring instruments for pressure and temperature are employed in almost all regions of industrial manufacturing. Due to continuous mechanical, chemical and thermal loading, these instruments age and can therefore not guarantee the correctness of the measured values during the period of time. Through timely calibration, however, the alteration of the measured value could be determined.
In the process of calibration, the displayed value of the measuring instrument is compared with the measuring consequence of a different measuring device that is known to function correctly and accurately and which itself has been designed to coincide directly or indirectly with a national (or international) reference instrument. In a nutshell, to compare measuring results, they must be ?traceable? to Strange or international standard with a chain of comparative measurements. Nest Egg shown in the picture (using the exemplory case of Germany) depicts the traceability of an inspection equipment in a company up to national standard at the PTB (German national metrology institute).
In order to ensure traceability used, the following points should be observed, amongst others:
The chain of comparison must not be interrupted.
The measurement uncertainty must be known in each stage of the calibration chain so the total measurement uncertainty can be calculated. As a rule, a superordinate measuring instrument must have a measurement accuracy three to four times higher.
Each part of the calibration chain must be documented, including the measurement results.
All bodies following a stage in the chain must prove their competence through accreditation.
Calibrations must be repeated at appropriate intervals. The periods depend on the demanded measurement accuracy and the technical requirements
Note
The WIKA calibration laboratory is accredited by the German Accreditation Body (Deutsche Akkreditierungsstelle ? DAkkS) in accordance with DIN EN ISO / IEC 17025 for the measurands temperature, pressure, DC current, DC voltage and DC resistance. Further information on our calibration laboratory or an on-site calibration with the WIKA calibration van can be found on the WIKA website. If you are thinking about our services, please feel absolve to contact us via e-mail.
Find out more about the differences between factory calibration and traceable calibration in the next video:

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