I, according to the structural characteristics of classification, measuring instruments can be divided into the following three categories:
(1) gauge. That is, with a fixed form of reproducing the value of measuring instruments, such as measuring blocks, weights, standard batteries, standard resistors, bamboo and wooden ruler. Line ruler, etc.;
(2) measuring instruments. To be measured quantity is converted into directly observable indicator value equivalent information measuring instruments, such as pressure gauges, flow meters, thermometers, ammeters. Electrocardiograph, etc.;
(3) measurement device. That is, in order to determine the measured value must be the overall combination of measuring instruments and auxiliary equipment, such as mileage meter calibration device, high-frequency microwave power meter calibration device.
Two, according to the classification of metrological purposes, measuring instruments can also be divided into the following three categories:
Measurement reference instruments, measurement standards, work measurement instruments. Measuring instruments is a basic content of metrological research, is the material basis for measurement. In the international arena, measuring instruments and measuring instruments is a synonymous term, it is defined as "individually or together with auxiliary equipment used to carry out the measurement of the apparatus", in our country measuring instruments are measuring instruments, also known as active; measuring instruments and gauges, also known as passive. Measuring instruments and measuring devices, according to the technical performance and use of measuring instruments can be divided into benchmarks, standards and general measuring instruments.
(1) benchmark measuring instruments measurement benchmark is in a particular field, with the highest contemporary measurement characteristics of its value does not have to refer to the same amount of other standards, and is designated or commonly recognized measurement standards. Recognized by international agreements, in the international community as the amount of all other standards based on the standard known as the international benchmark, officially recognized by the state, in the country as the amount of all other standards based on the standard known as the national benchmarks, benchmarks measuring instruments usually have the main benchmarks to testify to the benchmarks of the benchmarks of the secondary benchmarks of the reference reference benchmarks and the work of the benchmarks of the points. Benchmark measuring instruments of the main features:
1 in line with or close to the definition of the unit of measurement based on the basic principles.
2 good reproducibility and the definition of the realization of maintaining or reproducing the unit of measurement or its multiples or fractions of the highest contemporary or national accuracy.
3 Stability of the measurement characteristics over time.
4 The ability to transmit, by some method or means, the unit of measure, or its multiples or fractions, defined to be maintained or reproduced.
(2) measurement standard apparatus measurement standard is defined in order to achieve the realization of the preservation or reproduction of the amount of units or one or more values used as a reference to the physical gauge. Measuring instruments standard material or measurement system in our country customary for the benchmark is higher than the standard, which is measured from the characteristics of the consideration of measuring instruments at all levels of measurement standards must be directly or indirectly accept the national benchmarks for the transfer of quantitative value and can not be set on their own.
(3) ordinary measuring instruments ordinary measuring instruments refers to the general day-to-day work of the measuring instruments it can obtain a given quantitative measurement results.
Three, according to the level of classification, measuring instruments can be divided into the following three categories
(1) the scope of Class A measuring instruments:
1. The company's highest standard of measurement and measurement of standardized instruments;
2. Used in trade settlements, safety and security, health care and environmental monitoring, and included in the scope of mandatory testing of measuring instruments;
3. Production process and quality testing of key parameters with measuring instruments;
4. In and out of the plant material accounting with measuring instruments;
5. Precision testing of high accuracy or frequent use and poor reliability of measuring instruments.
Category A measuring instruments, including: a flat crystal, zero-level ruler, level gauge, right-angle ruler gauge, measuring tape gauge, percent gauge, micrometer gauge, self-collimator, vertical optical meter.
(2) the scope of Class B measuring instruments:
1. safety, health care and environmental monitoring, but is not included in the mandatory verification of the scope of measuring instruments;
2. production process is not a key parameter of the measuring instruments;
3. product quality of the general parameters of the detection of measuring instruments;
4. Second and third energy measurement with measuring instruments;
5. Internal material management with measuring instruments.
B class measuring instruments include: calipers, micrometers, measuring tape, micrometers, levels, right angles, plug rule, levels, latitude and longitude, welding inspection tape, ultrasonic thickness gauge, more than 5M tape measure, and thermometers, pressure gauges, force gauges, tachometers, scales, hardness testers, scales, voltmeters, ammeters, megohmmeters, power meters, bridges, resistance boxes, current detectors, multimeter, standard resistance boxes, calibration signals Standard resistance box, calibration signal generator, ultrasonic flaw detector, spectrophotometer and so on.
(3) the scope of C measuring instruments:
1. low value consumable, non-compulsory calibration of measuring instruments;
2. the company's living area of the internal energy distribution of measuring instruments, auxiliary production measuring instruments;
3. in the process of using the measurement of the data does not have the precise requirements of the measurement of the instruments;
4. the national measurement of the administrative department State measurement of administrative departments to allow a one-time verification of measuring instruments.
Category C includes steel ruler, curved ruler, 5M a steel tape measure.