Measuring instruments for pressure and temperature are used 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 over the course of time. Through timely calibration, however, the alteration of the measured value can be determined.
In the process of calibration, the displayed value of the measuring instrument is compared with the measuring consequence of another measuring device which is recognized to function correctly and accurately and which itself has been made to coincide directly or indirectly with a national (or international) reference instrument. In a nutshell, to compare measuring results, they must be ?traceable? to a national or international standard with a chain of comparative measurements. The calibration hierarchy shown in the picture (utilizing the example 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 in practice, the following points should be observed, among others:
The chain of comparison should not be interrupted.
เกจวัดแรงดัน should be known in each stage of the calibration chain so the total measurement uncertainty could be calculated. As a rule, a superordinate measuring instrument should have a measurement accuracy three to four times higher.
ไดอะแฟรม in the calibration chain must be documented, including the measurement results.
All bodies following a stage in the chain must prove their competence by way of 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. More info on our calibration laboratory or an on-site calibration with the WIKA calibration van are available on the WIKA website. Should you be thinking about our services, please feel absolve to e mail us via e-mail.
Find out about the differences between factory calibration and traceable calibration in the next video: