One important requirement of the quality assurance system is the traceability of a measuring instrument to national standards. This demand is generally based on ISO 9000 requirements. The traceability is given, if a measuring instrument or measuring system was calibrated in an uninterrupted chain using a reference, which in turn is traceable to national standard.
Determining, if a demand is fulfilled. Example: an air-operated shut-off screwdriver is torque tested against a torque transducer. If a deviation is detected, then the screwdriver must be readjusted.
Change made to the measuring instrument to eliminate a systematic measuring deviation.
Testing of a measuring system to agree with the calibration laws as required by the consumer protection agency. This includes checking whether the number of the measuring deviations of each instrument does not exceed the allowable error limits. Thereafter the measuring instrument will be certified by the testing agency or its representative. The calibration law clearly states which measuring instrument needs to be calibrated!
Measuring means comparing. A measuring instrument compares something unknown with something known. A measuring instrument needs to be checked, using a calibration process that measures an object with known standard. Any shown deviation for this measurement is called a measurement uncertainty. The smaller the deviation, the more accurate the measuring instrument is measuring.
A measuring instrument needs to be regularly checked, using a calibration process. Such a calibration process measures an object with known proportions. An object with known proportions is called a "Standard". There are standards in different hierarchy steps. These are compared in accordance with a concrete schematic. If the measuring instrument indicates the same value or is within the allowable tolerance range, then the measuring instrument fulfills the specified requirements.