Calibration in measurement technology and metrology is the comparison of measurement values delivered by a device under test with those of a calibration standard or reference of known accuracy.
Such a standard or reference could be:
- Another measurement device of known accuracy such as a reference thermometer, pressure meter, temperature mapping device, balance, etc.
- A device generating the quantity to be measured such as a reference temperature dry block, temperature water bath, temperature & humidity climatic chamber, vital sign simulator, pressure generator, etc.
- A physical artefact, such as a reference weight set, ocular micrometer, meter ruler, etc.
The outcome of the comparison can result in no significant error being noted on the device under test, a significant error being noted but no adjustment made, or an adjustment made to correct the error to an acceptable level. Strictly, the term calibration means just and only just the act of comparison of an unknown to a known and recording the results in a well referenced certificate, and does not include any subsequent adjustment.
The calibration references or standards are normally traceable to international / national standards held by International / National Metrological Institutes such as NPL, NIST, PTB, ILAC, ISO, DAkkS, UKAS, FINAS, DANAK, etc.
Calibration may be required to be called for the following reasons:
- A new instrument
- After an instrument has been repaired or modified
- When a specified time period has elapsed
- When a specified usage (operating hours) has elapsed
- After an event such as the exposure to a shock, vibration, sudden change in weather or physical damage, which might potentially have compromised the integrity of its calibration.
- Whenever observations appear questionable or instrument indications do not match the output of surrogate instruments.
- As specified by a requirement such as customer specification or instrument manufacturer recommendation.
After calibration is done, a process called adjustment (if possible) digs in which is often regarded as the process of amending the output or indication on a measurement instrument to agree with the value of the applied standard, within a specified accuracy of course. However, very few instruments can be adjusted to exactly match the standards they are compared to.
At SmartCal, all of the calibration services provided are traceable weather it is included in our accreditation scope or not. If the service is included in our accreditation scope, the certificate issued will be an ISO 17025 accredited certificate, if not, an authentic acceptable traceable certificate will be provided.