To improve the accuracy of the instrument, error analysis is necessary. Errors can generally be divided into inadvertent errors, slowly varying errors, systematic errors, and random errors. Negligent errors refer to man-made errors in the measurement process, which can be overcome and have nothing to do with the instrument itself. Slow change error is caused by the aging process of internal components of the instrument, which can be overcome and eliminated by replacing components, parts, or continuous correction.

However, for instrument users, such as instrument workers in chemical enterprises, instrument accuracy is certainly an important indicator, but in practical use, more emphasis is often placed on the stability and reliability of the instrument, because chemical enterprises' detection and process control instruments are rarely used for measurement, while a large number are used for detection. In addition, the stability and reliability of instrumentation used in process control systems are more important than accuracy.