Instrument calibration is the process of comparing various parameters in the output of a measuring instrument or device, against a reference instrument with known performance, which is also known as a standard. This lets a technician calculate the performance limitations, accuracy and precision of the instrument, so it can be suitably adjusted and brought within acceptable levels of accuracy or error.
Now, if the reference instrument or standard used is inaccurate, the resulting calibration will also be erroneous. To avoid this, various organizations, agencies and regulatory bodies, like the International System of Units (SI) maintain industry standards for calibration service providers to follow. The reference instrument used for calibration must have a known value which can, through a series of calibrations, be traced back to an accepted standard.
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