This standard adopts ISO 9110-1-1990. This standard specifies the general criteria for measuring the performance parameters of hydraulic components under static or steady-state conditions. This standard is a guiding document for analyzing the expected error sources and error magnitudes in the measurement of hydraulic components and the calibration of the measurement system. This standard is applicable to the measurement of hydraulic component performance parameters and the calibration of its measurement system. JB/T 7033-1993 General Rules for Hydraulic Measurement Technology JB/T7033-1993 Standard download decompression password: www.bzxz.net

Mechanical Industry Standard of the People's Republic of China
JB/T7033-93
Published on September 23, 1993
General Rules for Measurement Technology
Implemented on July 1, 1994
Ministry of Machinery Industry of the People's Republic of China
Mechanical Industry Standard of the People's Republic of China
General Rules for Hydraulic and Measurement Technology
JB/T 703393
This standard adopts the international standard ISO9110-1-1990 "Hydraulic transmission - Measurement technology - Part 1 General measurement standards Subject content and scope of applicationbzxZ.net
This standard specifies the general criteria for measuring the performance of hydraulic components under static or normal working conditions. This standard is a guiding document for analyzing the expected error sources and error sizes during the calibration process of the measurement base and measurement system of hydraulic components.
This standard is applicable to the measurement of performance parameters of hydraulic components and the calibration of their measurement systems. 2 Reference standards
JJG1001
Common metrological terms and definitions
3 Terms and definitions
This standard adopts the following term definitions.
3.1 Measurement measurement
All operations for the purpose of determining the value of the object being measured. 3.2 Measuring instrument measuring instrument An instrument or device that can be used alone or with auxiliary equipment to determine the value of the object being measured. 3.3 Measuring system measuring system
A complete set of measuring instruments and other equipment combined to perform a specific measurement task. 3.4 Reference standard referense standard The measuring instrument with the highest metrological quality available in a given area, which is used to calibrate measuring instruments for routine work in the same general category.
3.5 Measurement error error of measurement The difference between the measurement result and the true value of the measured object.
3.6Systematic errorsystematicerror
Under the same conditions, in the process of multiple measurements of the same quantity, the absolute value and sign remain constant, or when the conditions change according to a certain law when the measurement error component.
3.7Random errorrandomerror
Under the same conditions, in the multiple measurements of a quantity, the absolute value and sign of the measurement error component change in an unpredictable way.
:repeatability of measurements3.8
Repeatability of measurements
The consistency of the measurement results when the same quantity is measured successively in a short time by the same observer using the same measuring instrument at the same place. 3.9Static conditionsstaticconditions
Approved by the Ministry of Machinery Industry on September 23, 1993
Implemented on July 1, 1994
The state in which the parameters do not change with time.
3.10 Steady-state conditions JB/T7033-93
The average value of the variable does not change with time, and the change of the instantaneous value of the variable is periodic and can be described by a simple mathematical formula.
3.11 Calibration calibration
A set of operations to determine the relationship between the indication of a measuring instrument or measuring system and the corresponding indication of a reference standard under specified conditions. 3.12 Accuracy level accuracycyclasses The level of measurement that keeps the error within the specified range and meets certain metrological requirements. 3.13 Accuracy of measurement The degree of consistency between the measurement result and the true value of the measured (agreed). 4 Accuracy level
4.1 According to the different needs of the test, three measurement accuracy levels of A, BC are specified in various hydraulic component test method standards. Level A: Applicable to scientific identification tests.
Class B: Applicable to type tests of hydraulic components, or quality assurance tests of component manufacturers and selection and evaluation tests of users; Class C: Applicable to factory tests of hydraulic components, or acceptance tests of users. 4.2 The error range of each measurement accuracy level is obtained by adding the systematic error of the measurement system to the total random error, which is equal to the root mean square of the individual random errors in the measurement system. 5 Error classification
5.1 The error of the measurement system may be related to a single component in the measurement system or to the entire measurement system. Generally speaking, calibration and evaluation of the entire system can obtain a smaller error. 5.2 Fixed errors, such as known deviations from the true value observed during calibration, should be eliminated by adjusting the instrument or correcting the results. If it cannot be eliminated, the error should be taken as the maximum value of the systematic error. For example, when a pressure gauge is compared with a reference standard, it shows a 4% deviation in the indication in the middle of the range and a 2% deviation in the indication at both ends of the range. If the pressure gauge is not corrected when used, it should be considered that the pressure gauge has a 4% systematic error. 5.3 Certain errors are physically related to another variable (second variable) other than the measured variable and can be represented by a known mathematical function of the variable, such as the effect of temperature on the output of a pressure sensor. Errors caused by changes in the second variable can cause both systematic errors and random errors. If the error is negligible, such as the effect of temperature within a small temperature range, then only the maximum error that may exist within the allowable range of the second variable needs to be treated as a systematic error. If the effect of the second variable is corrected, it should be treated as a random error, the size of which is equal to the measurement error of the second variable.
5.4 All known errors in the upper calibration benchmark should be treated as systematic errors of the measured measurement. 5.5 Repeated measurement errors caused by repeatability should be treated as random errors. When determining the error of a single measurement, the full value of the repeated error of the measuring system determined in accordance with the provisions of Article 6.1.2 shall be taken. If the average value of \ readings is taken to determine the measured value, the error caused by repeatability is calculated as follows:
Where:, Random error
t--- Repeated error determined in accordance with the provisions of Article 6.1.2; 1--Number of measurements.
6 Assessment of accuracy
6.1 Calibration
6.1.1 Calibration shall be performed according to the prescribed method for each type of measuring system. Usually, the calibration method involves using the measuring system to measure an input excitation signal of a known value, or to reapply the same excitation signal at least 5 times at a certain measuring point and take the average value for comparison with a reference standard with a known calibration error. Calibration should be performed at a pre-specified point within the measuring system range. 6.1.2 At the jth calibration point, calculate the standard deviation S, using the following formula: S,
wherein, X,-the i-th measurement value,
-the average of several measurement values.
E(xx)
The maximum standard deviation obtained in this way is the repeatability error e of the measurement system. 6.2 Partial calibration
6.2.1 When it is not possible to calibrate at the number of points required by Article 6.1 due to economic considerations or limited conditions, the same calibration method can be used to perform partial calibration at fewer points. 6.2.2 The distribution of calibration points should be selected based on the characteristics of the measurement system and past calibration results, but should include the first and last two points of the actual range in use.
6.3 Calibration cycle
6.3.1 The calibration cycle should be determined based on the accuracy level and stability of the measurement system. Between two calibrations, the error related to the calibration error shall be the larger of the errors calculated in the two calibrations. If the error obtained in this way exceeds the application range, the cycle of the next calibration shall be halved and continued to be halved until the calibration result falls within the application range. If this still does not reach the Class C accuracy range, the measurement system shall be eliminated.
6.3.2 For Class A measurements, calibration shall be performed before each test or after 48 hours of continuous use, or when overflow, damage or calibration drift is suspected.
For Class B measurements, the calibration cycle shall not exceed 1 year, and the partial calibration cycle shall not exceed 1 month. For Class C measurements, partial calibration is required at least once a year. If the measurement system has not been used for an effective period of time that exceeds the prescribed calibration cycle, partial calibration shall be performed before it is used again. Additional notes:
This standard was proposed by the National Hydraulic and Pneumatic Standardization Technical Committee. This standard was drafted by the Beijing Institute of Automation of the Machinery Industry, Ministry of Machinery Industry. The main drafters of this standard are Wu Zhiming, Ba Jian, Yin Guohui, and Zhu Peihua 3
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