Traceability

Measuring instruments for pressure and temperature are used in almost all regions of industrial manufacturing. As a result of continuous mechanical, chemical and thermal loading, these instruments age and will 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 another measuring device that is known to function correctly and accurately and which itself has been made to coincide directly or indirectly with a national (or international) reference instrument. In short, in order to compare measuring results, they must be ?traceable? to Unheard Of or international standard with a chain of comparative measurements. The calibration hierarchy shown in the picture (using the example of Germany) depicts the traceability of an inspection equipment in an organization up to national standard at the PTB (German national metrology institute).
In order to ensure traceability used, the following points must be observed, among others:
The chain of comparison must not be interrupted.
The measurement uncertainty must be known in each stage of the calibration chain in order that the total measurement uncertainty could be calculated. Generally, a superordinate measuring instrument should have a measurement accuracy 3 to 4 times higher.
Each step in the calibration chain must be documented, including the measurement results.
All bodies carrying out a stage in the chain must prove their competence through accreditation.
Calibrations must be repeated at appropriate intervals. The periods be determined by 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. For anyone who is thinking about our services, please feel absolve to e mail us via e-mail.
Know more about the differences between factory calibration and traceable calibration in the following video:

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