ISO1OO12-1 "Quality Assurance Requirements for Measuring and Testing Equipment" standard defines "calibration" as: "A set of operations performed under specified conditions to determine the relationship between the indicated value of a measuring instrument or measuring system or the value represented by a physical gauge or standard and the known value of the corresponding measured substance. A set of operations to determine the relationship between the indicated value of a measuring instrument or measuring system or the value represented by a physical gage or standard substance and the corresponding known value of the measured.
Note:
1. The results of calibration can be used to assess the error in the value of a measuring instrument, measuring system or physical gauge, or to assign a value to the markings on any scale;
2. Calibration can also be used to determine other metrological characteristics;
3. The results of calibration can be recorded in a document sometimes referred to as the certificate of calibration or calibration report;
4. Sometimes the approved results are expressed as corrected values, calibration factors or calibration curves.
Based on the above definitions, it can be seen that there is a fundamental difference between calibration and verification. The two can not be confused, not to mention equivalent. The purpose of calibration is against the measurement standard, evaluation of the measurement device value error, to ensure that the value is accurate, belongs to the bottom-up traceability of a group of operations. The evaluation of this error should be based on the organization's calibration procedures to make the appropriate provisions, according to the calibration cycle, and make a good calibration records and calibration mark. Calibration in addition to assessing the error in the display value of the measuring device and determine the relevant measurement characteristics, calibration results can also be expressed as a correction value or calibration factor, specific guidance for the operation of the measurement process. For example, a machining organization to use calipers, calibration found with the measurement standard has been compared with O.2mm, this data can be used as a correction value, in the calibration logo and records marked in the calibration of the value of the standard compared to the larger out of the O.2mm value. In the use of this measuring instrument (calipers) for the physical measurement process, minus O.2mm out of the corrected value of the measured value of the physical measurement. As long as the purpose of traceability can be achieved, a clear understanding of the measuring instruments of the value of the error, that is, to achieve the purpose of calibration.
The purpose of the verification is a mandatory comprehensive assessment of the measuring device. This comprehensive evaluation belongs to the scope of the unity of value, is the top-down value transfer process. Verification should be assessed whether the measuring instrument meets the specified requirements. This requirement is the measurement of the measurement device calibration specification of the error range. Through the calibration, assessment of the measuring device error range is within the specified error range. The object of calibration is to belong to the mandatory calibration outside the measuring device. China's non-mandatory calibration of measuring devices, mainly in the production and service delivery process of measuring instruments used in large quantities, including incoming inspection, process inspection and final product inspection of measuring instruments used.
The object of verification is the measurement of China's measurement law clearly stipulates the mandatory verification of measuring devices. People's Republic of China *** and State Measurement Law "Article IX clearly states:" the people's government at or above the county level measurement of the administrative departments of the social public measurement standard instruments, departments and enterprises, institutions using the highest measurement standard instruments, and for trade settlement, safety and security, medical and health, environmental monitoring included in the mandatory inspection of directory of measuring instruments, the implementation of mandatory verification. Not in accordance with the provisions of the application for verification or unqualified verification, shall not be used."
Therefore, the object of verification is mainly three major categories of measuring instruments. These are:
1. Measurement benchmarks (including international [measurement] benchmarks and national [measurement] benchmarks) ISO 1OO12-1< measurement and testing equipment for quality assurance requirements" is defined as: International [measurement] benchmarks: "Recognized by international agreement, in the international as the amount of all other measurement benchmarks based on the value of the measurement benchmarks. International [metrological] datum: "A metrological datum recognized by international agreement as the basis for the international fixing of all other metrological datums for the quantity in question."' National [Measurement] Benchmark: "A measurement reference recognized by an official decision of the State as the basis for the domestic fixing of all other measurement standards for the quantity in question."''
2. [Measurement] standards The ISO 1OO12-1 standard defines a [measurement] standard as; 'a physical gauge, measuring instrument, standard substance or system for defining, realizing, maintaining, or reproducing a unit or one or more known quantities and for transferring them by comparison to other measuring instruments (e.g.: a.1 kg in a mass standard; b. a standard block; c. a 1O0Ω standard resistor; d. a Weston standard cell)."
3. China's Measurement Law and the Chinese people *** and the State mandatory verification of the work of measuring instruments detailed catalog movement Provides that "where used for trade settlement, safety and protection, medical and health, environmental monitoring, are subject to mandatory verification." In this detailed catalog, it has been clearly stipulated that 59 kinds of measuring instruments listed in the scope of mandatory verification. It is worth noting that this "detailed directory" of the second paragraph clearly emphasizes that "the catalog items, where used in trade settlement, safety and security, medical and health care, environmental monitoring, are the implementation of mandatory verification." This is the requirement listed in the 59 kinds of compulsory inspection catalog of measuring instruments, only for trade settlement and other four types of measuring instruments in the field, belong to the scope of compulsory verification. Although included in the 59 kinds of measuring instruments directory, but the actual use is not for trade settlement and other four categories of measuring instruments, may not belong to the scope of mandatory verification. Measuring devices outside the above three categories belong to the non-compulsory verification, that is, the scope of calibration. Calibration is not mandatory, belongs to the organization's voluntary traceability behavior. This is a technical activity, according to the actual needs of the organization, the evaluation of measuring instruments, measuring instruments or standard substances for the value of the process. The organization can specify the calibration specification or calibration method according to the actual needs. Self-regulation of calibration cycle, calibration marks and records.
Checking belongs to the mandatory law enforcement behavior, belongs to the scope of legal measurement management. Which the calibration protocol agreement cycle and so on all in accordance with the statutory requirements. Calibration of the main basis for the organization in accordance with the actual needs of their own "calibration specification", or with reference to the "verification procedures" requirements. In the Calibration Specification, the organization stipulates its own calibration procedures, methods, calibration cycles, calibration records and marking requirements. Therefore, the Calibration Specification is a guiding document for the organization to implement calibration.
The main basis for verification is the "Measurement and Certification Regulations", which is the measurement of equipment verification must comply with the statutory technical documents. Which, usually on the measurement of testing equipment verification cycle, measurement characteristics, test items, test conditions, test methods and test results and other provisions. Measurement verification regulations can be divided into national measurement verification regulations, departmental measurement verification regulations and local measurement verification regulations. These regulations belong to the measurement of regulatory documents, organizations do not have the right to develop, must be approved by the authorized measurement department. Calibration of the organization can be used to self-calibration, external school, or self-calibration and external school combined. Organization in the case of conditions, you can use self-calibration of measuring instruments for calibration, thus saving greater costs. Organizations to carry out self-calibration should pay attention to the necessary conditions, rather than relaxing the requirements of the management of measuring instruments. For example, it is necessary to prepare calibration specifications or procedures, calibration cycle, with the necessary calibration environment and have a certain quality of measurement personnel, at least one level higher standard measuring instruments, so that the calibration error as small as possible. In most areas of measurement, the measurement error of the standard should be no more than 1/3 to 1/10 of the error of the equipment being recognized in use. In addition, provisions should be made for calibration records and marking. Through the above provisions, the accuracy of the measurement value is ensured.
The calibration must be carried out to the qualified measurement department or legally authorized unit. According to the status quo in China, most production and service organizations are not qualified for calibration, only a few large organizations or professional metrological verification departments have such qualifications. The calibration cycle is determined by the organization itself according to the needs of the use of measuring instruments. Can carry out regular calibration, can not be calibrated regularly, or calibrated before use. The principle for determining the calibration cycle should be to maintain minimal calibration costs while minimizing the risk of the measurement device in use. Can be based on the frequency of use of measuring instruments or the degree of risk to determine the period of calibration.
The cycle of calibration must be carried out in accordance with the provisions of the "calibration regulations", the organization can not determine their own. Calibration cycle is a mandatory binding content. Calibration of the content and the project, only to assess the measurement device value error, to ensure that the value is accurate.
The content of the verification is a comprehensive evaluation of the measuring device, the requirements of a more comprehensive, in addition to including all the contents of the calibration, but also need to verify the project.
For example, a measuring instrument verification content should include the technical conditions of measuring instruments, verification conditions, verification items and verification methods, verification cycle and the disposition of verification results and other content. The content of calibration can be determined by the organization itself according to the needs. Therefore, according to the actual situation, the test can replace the approval, while the calibration can not replace the test. The conclusion of calibration is only to assess the measurement error of the measuring device to ensure the accuracy of the measurement value, and it is not required to give the judgment of pass or fail. The results of calibration can be given "calibration certificate" or "calibration report".
The test must be based on the "test procedures" specified in the range of error in the value of the measuring device to give a qualified or unqualified judgment. Out of the "test procedures" specified range of error in the measurement value for failure, within the specified range of error in the measurement value is qualified. The result of the calibration is to give the Certificate of Conformity. The conclusion of the calibration does not have the legal effect, given the "calibration certificate" is only marked with the measurement value error, belongs to a technical document.
The conclusion of the verification has legal effect, can be used as a measuring instrument or measuring device verification of the legal basis for the verification certificate belongs to a technical document with legal effect.