Metrological Lineage
The uninterrupted chain of comparisons connecting a measurement result to an international reference standard guarantees the reliability of industrial calibrations. Establishing traceability ensures that measurements made on the factory floor can be directly related to the base units of the international system of units. This connection is maintained through a documented series of calibrations, each with an associated uncertainty, which allows for the global comparison of measurement data across different industries.
Calibration Chain
Each link in the chain represents a comparison between an instrument and a higher-level reference standard of greater accuracy. The factory sensor is calibrated against a working standard, which is in turn calibrated against a reference standard at an accredited laboratory. This sequence continues up to the national reference standards maintained by national metrology institutes.
Uncertainty Accumulation
Every step in the measurement chain adds to the total measurement uncertainty of the final calibration. The uncertainty of the national standard is the smallest, and each subsequent comparison introduces additional variance from environmental factors, operator technique, and instrument drift. Calculating this accumulated error is necessary to define the accuracy of the final measurement.
Compliance Requirement
Quality standards require documented proof of this continuous measurement chain for all critical testing instruments. Auditors inspect calibration certificates to verify that each instrument has a current and valid link to a recognized national standard. This verification ensures the international acceptance of the manufacturer’s products.
