Calibration: establishing a measurement relationship
Calibration considers the relationship between reference values and instrument indications under specified conditions, including measurement uncertainties. It does not mean the instrument has been adjusted or found suitable for every use.
Verification: does it meet the specified requirement?
Verification provides objective evidence that an item meets specified requirements. The requirement and assessment method must be defined first.
Adjustment: changing the instrument's behaviour
Adjustment covers operations intended to make the instrument indication correspond to desired values. As measurement behaviour may change afterwards, the need for calibration should be assessed.
Specify the operation clearly in your request
Distinguish between calibration, adjustment and conformity assessment in your service request. Agree in advance whether results before and after adjustment are required.
Further reading
For metrology concepts, consult JCGM publications, and for calibration intervals, consult ILAC guidelines . This article provides general information; assessments specific to your equipment and process must consider the applicable requirements.