TC

Calibration can be briefly described as an activity where the instrument being tested is compared to a known reference value. At the simplest level, calibration is a comparison between measurements – one of known magnitude or correctness made or set with one device, and another measurement made in as similar a way as possible with a second device. The device with the known or assigned correctness is called the standard. The second device is the unit under test or test instrument.

Calibration is often required with a new instrument or when a specified time period or a specified number of operating hours has elapsed. In addition, calibration is usually carried out when an instrument has been subjected to an unexpected shock or vibration that may have put it out of its specified limits.