he method of determining the accuracy level of the multimeter
If the meter measures multiple parameters, how is the accuracy level of the meter determined?
The absolute value of the maximum relative percent error of the meter is used as the accuracy class, where:
The accuracy of the primary standard instrument is: 0.005, 0.02, 0.05.
The accuracy of the secondary standard instrument is: 0.1, 0.2, 0.35, 0.5.
The accuracy of general industrial instruments is: 0.1, 0.2, 0.5, 1.0, 1.5, 2.5, 5.0
Relative percent error = (measured value of the measured parameter - standard value of the measured parameter) ÷ (the upper limit of the scale - the lower limit of the scale) × 100%.
The accuracy grade is divided by its allowable error as a percentage of the dial scale value. The larger the range, the greater the allowable error of the absolute value of the measured pressure value for the same accuracy level. The commonly used precision is 2.5 and 1.5. If it is 1.0 and 0.5, it belongs to high precision. Now some numbers have reached 0.25.
The representation method of error is divided into: reference error, relative error, absolute error.
Reference error = (maximum absolute error/meter range) × 100%
Example: 2% F.S.
Relative error = (maximum absolute error / instrument measurement value) × 100%
For example: ≤2%, the absolute error refers to how much the error deviates from the true value.
For example: ≤±0.01m3/s
Under normal conditions of use, the accuracy of the measurement results of the instrument is called the accuracy of the instrument. In industrial measurement, in order to express the quality of the instrument, the accuracy level is usually used to indicate the accuracy of the instrument. The accuracy level is the maximum reference error minus the positive, negative and percent signs.
The accuracy grade is one of the important indicators to measure the quality of the instrument. The industrial instrument grades in my country are divided into seven grades: 0.1, 0.2, 0.5, 1.0, 1.5, 2.5, and 5.0, and are marked on the scale or nameplate of the instrument. The accuracy of the instrument is habitually called the precision, and the accuracy level is habitually called the precision level.
Meter accuracy = (maximum absolute error/meter range) * 100%.
Taking the absolute value of the above calculation formula and removing % is the accuracy level we see.
The instrument accuracy is divided into several grades according to the allowable error size stipulated by the state. The allowable error of a certain type of instrument refers to the maximum allowable percentage error under specified normal conditions.
The accuracy levels of process detection and control instruments in my country are 0.005, 0.02, 0.1, 0.35, 0.5, 1.0, 1.5, 2.5, and 4. General industrial meters are 0.5 to 4 grades. The smaller the precision number, the higher the accuracy of the meter.
