Classification standard of instrument accuracy grade

1. The country uses the absolute value of the maximum relative percentage error of the instrument as the accuracy level, where: The accuracy of the first-level standard instrument is: 0.0050.020.05 The accuracy of the second-level standard instrument is: 0.10.20.350.5 General industry The accuracy of the instrument used is: 1. 1.5 2.5 4.0 Relative percentage error u003d (measured value of the north test parameter-standard value of the north side parameter)/(1. The country uses the absolute value of the maximum relative percentage error of the instrument as Accuracy grade, among which: the accuracy of the first-level standard instrument is: 0.0050.020.05 The accuracy of the second-level standard instrument is: 0.10.20.350.5 The accuracy of the general industrial instrument is: 1. 1.5 2.5 4.0 relative percentage error u003d (Measurement value of north survey parameter-standard value of north side parameter) / (scale upper limit value-scale lower limit value) * 100% 2. How are the accuracy grades of our country's instruments divided? Basic error: basic error is also called reference Error or relative error is a simplified relative error. The basic error of the instrument is defined as: basic error u003d (maximum absolute error / instrument range) * 100 u003d u003d (indicated value of the detection instrument-measured true value) MAX / ( Measurement upper limit-measurement lower limit) * 100% accuracy (accuracy for short) In order to facilitate the transmission of the measurement value, the state uniformly stipulates the accuracy (precision) grade series of the instrument. The basic error of the instrument is removed from the '±' sign and '%' sign , It can be set into the national unified instrument accuracy grade series. 　　 At present, the commonly used accuracy grades of meters produced in China are 0.005, 0.02, 0.05, 0.1, 0.2, 0.4, 0.5, 1.0, 1.5, 2.5, 4.0, etc. If If the basic error of a temperature measuring instrument is ±1.0%, it is considered that the accuracy level of the instrument meets the level of 1.0. If the basic error of a temperature measuring instrument is ±1.3%, it is considered that the accuracy level of the instrument meets the level of 1.5 。The smaller the number of stages, the higher the accuracy (accuracy). The accuracy grades of instruments used in scientific experiments are above 0.05; most of the instruments used in industrial testing are at 0.1 to 4.0, and most of the standard meters used for calibration are 0.1 or 0.2. Mostly used in the field are 0.5 to 4.0. The industrial detection instruments are mostly 0.1 to 4.0. I have seen the following 3 different statements in different places: 1. The industrial instrument grades in China are divided into 0.1, 0.2, 0.5, There are seven grades of 1.0, 1.5, 2.5, and 5.0, and they are marked on the scale or nameplate of the meter. 2. There are seven grades of 0.1, 0.2, 0.5, 1.0, 1.5, 2.5, and 5.0 for electrical instruments in China. 3. Unified by country The accuracy grades of the instrument are divided into: 0.005, 0.02, 0.05, 0.1, 0.2, 0.35, 0.4, 0.5, 1.0, 1.5, 2.5, 4.0, etc.