Calibration, verification, calibration and verification
Improve the operation of instrument or system accuracy (precision) by compensating for instrument system error by measuring the deviation of the standard. Calibration is generally used for instruments with higher precision.
According to the national metrological verification regulations, through the experiment to determine whether the error of the measurement instruments meet the requirements of the activity. The verification range is the compulsory verification of measuring instruments stipulated in the metrology law of our country.
According to the relevant calibration specification, the activity of indicating the value of the measuring instrument is determined by experiment. Usually, the error of the measured instrument relative to the standard is obtained by comparing with the standard with higher precision, so as to obtain the correction of the indicated value of the measured instrument. Calibration is mainly used for non-compulsory verification of measuring instruments.
In the absence of relevant verification regulations or calibration specifications, a way to implement quantity-value transmission traceability in accordance with the methods developed by the organization itself. It is mainly used for special measuring instruments or measuring instruments with relatively low accuracy.
The meaning and difference of calibration, verification, calibration and verification
I. Calibration meaning:
The use of standard measuring instruments to test whether the accuracy (accuracy) of the instrument used meets the standard, which is generally mostly used for instruments with higher precision.
1. Determine the input-output relationship of the instrument or measuring system, and assign the index value to the instrument or measuring system;
2. Determine the static characteristics of the instrument or measuring system;
3. Eliminate system errors and improve the accuracy of the instrument or system;
4. In scientific measurement, calibration is an important step that cannot be ignored;
Ii. Verification meaning:
In the absence of relevant verification regulations or calibration specifications, a way to implement quantity-value transmission traceability in accordance with the methods developed by the organization itself. Mainly used for special measuring instruments or measuring instruments with relatively low accuracy and testing hardware or software.
Iii. Verification meaning:
The activity in which the legal metrology department or the legally authorized organization, in accordance with the verification regulations, provides proof through experiments to determine that the indicating error of the measuring instrument meets the specified requirements.
Iv. Calibration meaning:
Under the specified conditions, in order to determine the indicator value of the measuring instrument or measuring system or the indicator value represented by the physical measuring tool or standard material, the same measured object is tested by the verified and qualified standard equipment and the measured equipment with higher accuracy, and a set of operations are obtained to obtain the error of the measured equipment relative to the standard equipment, so as to obtain the correction value of the indicated value data of the measured equipment.
5. The main differences between calibration and verification, calibration and verification
1. Calibration is a dynamic process in which the accuracy of the test equipment is reviewed and the error is eliminated in time.
2. Verification, calibration and verification are static measurement processes carried out periodically.
Vi. Main differences between verification and calibration
(1) Different purposes
The purpose of calibration is to evaluate the indicating error of the measuring device against the measurement standard and ensure the accuracy of the quantity value, which belongs to a group of operations from the bottom up.
The evaluation of such indication error shall be made according to the calibration procedure of the organization, and shall be carried out according to the calibration cycle with calibration records and calibration labels.
In addition to evaluating the indication error of the measuring device and determining the relevant measurement characteristics, the calibration result can also be expressed as a correction value or calibration factor, which specifically guides the operation of the measurement process. For example, the caliper used by a machining organization is found to be 0.2mm larger than the measurement standard through calibration, and this data can be used as a correction value. Indicate in the calibration identification and records that the calibrated value is 0.2mm larger than that of the standard. In the process of using this measuring instrument (caliper) for physical measurement, subtract the correction of 0.2mm, the actual value of the physical measurement. As long as the purpose of the measurement value traceability can be achieved and the error of the indication value of the measuring instrument is clearly understood, the purpose of calibration is achieved.
Purpose of verification: mandatory comprehensive assessment of measuring devices. This kind of comprehensive evaluation belongs to the scope of the unity of quantity and value, and is the process of the transfer of quantity and value from top to bottom. Verification shall assess whether the measuring instrument complies with the specified requirements. This requirement is the error range specified in the verification regulations of measuring devices. Through verification, evaluate whether the error range of the measuring device is within the specified error range.
(2) Different objects
The object of calibration is a measurement device that is not subject to mandatory verification. China's non-mandatory verification of measuring devices, mainly refers to a large number of measuring instruments used in the process of production and service provision, including incoming inspection, process inspection and final product inspection of the measuring instruments used.
The object of verification is the compulsory verification measuring device stipulated in the metrology law of our country. Article 9 of the Metrology Law of the People's Republic of China clearly stipulates: "The metrological administrative department of the people's government at or above the county level shall carry out compulsory verification of the public standard measuring instruments, the highest standard measuring instruments used by departments, enterprises and institutions, and the working measuring instruments listed in the list of people's strong inspection in the fields of trade settlement, safety protection, medical and health care anenvironmentalmonitoring." Those that fail to apply for verification in accordance with regulations or fail to pass verification shall not be used."
Therefore, the object of verification is mainly three categories of measuring instruments, which are:
1. Measurement basis
(including: international [metrological] benchmarks and national [metrological] benchmarks)ISO10012-1< Quality Assurance Requirements for metrological testing Equipment "is defined as: international [metrological] benchmarks:" recognized by international agreements as the basis for setting values for all other metrological benchmarks of the quantity concerned." National [metrological] benchmark: "A metrological benchmark recognized by an official national decision as the basis for setting values for all other metrological standards of the quantities concerned in the country.
The ISO10012-1 standard defines a "metrology" standard as "a physical measuring instrument, measuring instrument, reference material or system used to define, achieve, maintain or reproduce units or one or more known values of quantities and to transfer them by comparison to other measuring instruments (e.g., A. 1kg quality standard; b. Standard measuring block; c.100Ω standard resistance; d. Weiss... Ton standard battery)."
3. China's metrology law and the People's Republic of China compulsory verification of the working measuring equipment detail provisions, "where used for trade settlement, safety protection, medical health, environmental monitoring, compulsory verification."
In this detailed catalogue, it has been clearly stipulated that 59 kinds of measuring instruments are listed in the mandatory verification range. It is worth noting that the second paragraph of this "detailed catalogue" clearly emphasizes that "the items in this catalogue, where used for trade settlement, security protection, medical and health, environmental monitoring, are subject to compulsory verification." This is the requirement to list 59 kinds of measuring instruments in the strong inspection catalogue, only the measuring instruments used in four categories of fields, such as trade settlement, belong to the scope of compulsory verification. Although listed in the list of 59 measuring instruments, but the actual use of measuring instruments is not used for trade settlement and other four categories of fields, do not belong to the scope of compulsory verification. Measuring devices other than the above three categories belong to the non-mandatory verification, that is, the scope of calibration.
(3) Different nature
Calibration is not mandatory and belongs to the voluntary traceability behavior of the organization. This is a technical activity, according to the actual needs of the organization, to assess the measurement instrument indicating error, for the measuring instrument or the standard material value of the process. The organization may specify calibration specifications or calibration methods according to actual needs. Define calibration cycle, calibration mark and record...
Verification is a mandatory law enforcement act and belongs to the category of legal measurement management. Among them, the verification regulation agreement cycle and so on are all carried out in accordance with legal requirements.
(4) Different basis
The main basis for calibration is the Calibration Specification formulated by the organization according to the actual needs or the requirements of the National Metrology Technical Specification (JJF). In the "Calibration Specification", the organization shall specify the requirements of calibration procedures, methods, calibration cycles, calibration records and marks, etc. Therefore, the Calibration Specification is a guiding document for the organization to implement calibration.
The main basis of the verification is the National Metrological Verification Regulation (JJG), which is the legal technical document that must be followed for the verification of metrological equipment. Among them, the verification cycle, measurement characteristics, verification items, verification conditions, verification methods and verification results of measurement testing equipment are usually stipulated. Metrological verification regulations can be divided into three kinds: national metrological verification regulations, departmental metrological verification regulations and local metrological verification regulations. These procedures are metrological legal documents, the organization has no right to develop, must be approved by the authorized metrological department.
(5) Different methods
The way of calibration can be carried out by organizing self-calibration, external calibration, or a combination of self-calibration and external calibration.
If the organization has the conditions, it can use the self-calibration method to calibrate the measuring instruments, thus saving a large cost.
The organization of self-calibration should pay attention to the necessary conditions, rather than relaxing the requirements of the management of measuring instruments, for example, must prepare calibration specifications or procedures, specify the calibration cycle, have the necessary calibration environment and have a certain quality of metrology personnel, at least have a higher level of standard measuring instruments, so that the calibration error is as small as possible (in most measurement fields, The measurement error of the standard should not exceed 1/3 to 1/10 of the error of the confirmed equipment in use).
In addition, calibration records and marking should be provided for. Through the above regulations, ensure the accuracy of the quantity value.
Verification must be carried out at a qualified metrological department or legally authorized unit. According to the current situation of our country, most production and service organizations do not have the qualification, only a few large organizations or professional metrological verification departments have this qualification.
(6) Different cycles
The calibration period is determined by the organization itself according to the needs of the use of measuring instruments. Calibration can be performed periodically, irregularly, or before use. The principle of determining the calibration period should be to maintain the minimum calibration costs while minimizing the risk of the measuring equipment in use. The calibration period can be determined according to the frequency of use of the measuring instrument or the degree of risk.
The cycle of verification must be carried out in accordance with the provisions of the Verification Regulations, and the organization cannot determine it by itself. Verification cycle is a mandatory constraint.
(7) Different contents
The content and items of calibration are only to assess the indication error of the measuring device to ensure the accuracy of the quantity value.
The content of verification is a comprehensive assessment of the measuring device, requiring more comprehensive, in addition to including the whole content of calibration, but also need to verify the relevant items.
For example, the verification content of a certain measuring instrument should include the technical conditions of the measuring instrument, verification conditions, verification items and verification methods, verification cycle and the disposal of verification results. The content of calibration can be determined by the organization as needed. Therefore, according to the actual situation, verification can replace approval, and calibration cannot replace verification.
(8) Different conclusions
The conclusion of calibration is only to evaluate the measurement error of the measuring device and ensure the accuracy of the measurement value, and does not require the judgment of passing or failing. The result of calibration can be given the Calibration Certificate or Calibration Report.
According to the error range of the measurement value stipulated in the verification regulations, the qualified and unqualified judgment of the measuring device must be given. It is unqualified if it exceeds the error range of the quantity value stipulated in the Verification Regulations, and qualified if it is within the error range of the quantity value stipulated. The result of the verification is to give the verification Certificate
(9) Different legal effects
The conclusion of calibration does not have legal effect, and the calibration certificate given only indicates the error of the quantity value, which belongs to a technical document.
The verification conclusion has legal effect and can be used as the legal basis for the verification of measuring instruments or measuring devices. The Verification Certificate is a technical document with legal effect.
Vii. General use of calibration, verification, calibration selection:
1. Belong to the national compulsory verification list, submit for inspection;
(2) Outside the national compulsory verification list, but there is JJG or JJF, submit/calibrate, or the enterprise has standard equipment, appliances and calibration methods, can be self-calibrated;
3. If there is no JJG or JJF, verify it by yourself.