- Defined by the ‘International Organization for Standardization’ as:
The set of operations that establish, under specified conditions, the relationship between values indicated by a measuring instrument, a measuring system or values represented by a material measure, and the corresponding known values of a measurand
- Calibration checks for accuracy and linearity by comparing measurements with known values (standards) at set points
- Thus, it ensures that the measured value equates to the input value at these points
- Used to ensure reliability in a measurement system:
- Confirm accuracy and precision of measurement
- Remove the effects of drift (offset and gradient)
- These variations in measurement systems may occur due to:
- Manufacturing variations
- Differing system designs
- Change in response to environmental parameters (heat, cold, humidity)
- Ageing of systems over time