In the process of instrument calibration with instruments and equipment, due to the influence of various factors, the true value of the measured value is often not obtained. When the measurement accuracy is high, the measured value must be corrected. There are two modification methods: modification value and modification method.

1 Concept of correction value and correction factor

1) Add the correction value to the uncorrected measurement result by algebraic method to compensate for the systematic error value. The correction value is equal to the systematic error, but the sign is opposite.

2) The correction factor is a digital factor that compensates for the systematic error and multiplies the uncorrected measurement result.

2 Obtaining correction value and correction factor

1) Directly obtain the verification or calibration certificate.

2) Calculate or analyze the correction value and correction factor based on the results in the verification/calibration certificate.

3 Applicable occasions for correction value and correction factor All instruments and equipment have correction values or correction factors after verification/calibration. In actual measurement, some occasions require corresponding correction of the measurement results, but in some cases, as long as the correction value or correction factor has no obvious effect on the accuracy of the test results, it can be ignored.

The details are as follows: The following situations require correction with correction value or correction factor

When the measurement results of the instrument and equipment are not related to the operation of the test results, but the corresponding test method has clear requirements for its accuracy, not only the verification or calibration results need to meet the requirements of the relevant measurement regulations, but also the corresponding correction value or correction factor needs to be applied.

When the measurement results of the instrument and equipment are involved in the calculation of the test results or the direct reading of the test results, not only the verification or calibration results must meet the requirements of the relevant measurement procedures, but also the corresponding correction value or correction factor must be applied.

When the accuracy level of the instrument and equipment is equal to or slightly higher than the accuracy level required by the test method, not only the verification or calibration results must meet the requirements of the relevant measurement procedures, but also the corresponding correction value or correction factor must be applied.

The following situations do not require correction with correction factor

When the measurement results of the instrument and equipment are not related to the operation of the test results, and the corresponding test method has no clear requirements for its accuracy, as long as its verification or calibration results meet the requirements of the relevant measurement regulations, there is no need to apply correction value or correction factor.

When the test results of the instrument are reported in non-numerical form (such as negative, positive, detected, not detected, etc.), as long as the verification or calibration results of the instrument used for the test meet the requirements of the relevant measurement regulations, there is no need to apply the correction value or correction factor.

When the accuracy level of the instrument is much higher than the test method requirements, as long as its verification or calibration results meet the requirements of the relevant measurement regulations, there is no need to apply the correction value or correction factor.