State system for ensuring the uniformity of measurements. Ensuring the effectiveness of measurements in the management of technological processes. Metrological examination of technical documentation. The main tasks of the metrological examination of technical documentation

06.02.2022

Document's name:	MI 2267-2000 GSI. Ensuring the efficiency of measurements in process control. Metrological examination of technical documentation
Document Number:	2267-2000
Document type:	MI
Host body:	FSUE "VNIIMS"
Status:	Inactive
Published:	official publication M., 2000
Acceptance date:	January 01, 2000
Expiration date:	January 01, 2005

State system for ensuring the uniformity of measurements

Ensuring the effectiveness of measurements in the management of technological
processes. Metrological examination of technical documentation

INFORMATION DATA

1. DEVELOPED by the All-Russian Research Institute of Metrological Service (VNIIMS)

PERFORMERS: N.P.Mif, Ph.D. (theme leader)

2. APPROVED: VNIIMS

3. REGISTERED: VNIIMS


Document Number






RD 50-160-89

4. REPLACE MI 2267-93

This recommendation establishes the definition, goals, objectives, organization of work, main types of technical documentation subject to metrological examination, execution and implementation of the results of metrological examination of technical documentation.

1. GENERAL PROVISIONS

1.1. Metrological examination of technical documentation is the analysis and evaluation of technical solutions in terms of metrological support (technical solutions for the choice of measured parameters, the establishment of requirements for measurement accuracy, the choice of methods and measuring instruments, their metrological maintenance).

1.2. Metrological expertise is part of the complex of works on metrological support and may be part of the technical expertise of design, technological and project documentation.

1.3. During the metrological examination, erroneous or insufficiently substantiated decisions are revealed, recommendations are developed on specific issues of metrological support.

Metrological expertise contributes to the solution of technical and economic problems in the development of technical documentation.

1.4. Metrological examination can be omitted if, in the process of developing technical documentation, metrological study was carried out by the involved specialists of the metrological service.

1.5. Metrological expertise includes metrological control of technical documentation.

Metrological control is a check of technical documentation for compliance with specific metrological requirements regulated in standards and other regulatory documents.

For example, checking for compliance with the requirements of GOST 8.417 of the names and designations of the units of physical quantities specified in the technical documentation or checking for compliance with GOST 16263, RMG 29-99 of the metrological terms used.

1.5.1. Metrological control can be carried out within the framework of standard control by the forces of standard controllers specially trained in the field of metrology.

1.5.2. Decisions of experts during metrological control are binding.

1.6. The general goal of metrological expertise is to ensure the effectiveness of metrological support, the fulfillment of general and specific requirements for metrological support by the most rational methods and means.

The specific goals of the metrological examination are determined by the purpose and content of the technical documentation.

For example, a specific goal of metrological examination of drawings of the simplest parts may be to ensure the reliability of measurement control with optimal values for the probabilities of rejection of control of the 1st and 2nd kind.

2. ORGANIZATION OF WORKS TO CARRY OUT THE METROLOGICAL EXAMINATION

2.1. When organizing metrological expertise, the following activities are carried out at the enterprise:

- determination of the subdivision whose specialists should carry out the metrological examination;

- development of a regulatory document that establishes a specific procedure for conducting metrological examination at the enterprise;

- appointment of experts;

- training and advanced training of experts;

- formation of a set of regulatory and methodological documents, reference materials necessary for the metrological examination.

2.2. Typical forms of organization of metrological expertise:

- by experts-metrologists in the metrological service of the enterprise (this form of organization of metrological examination is preferable with relatively small volumes of technical documentation being developed);

- by the forces of specially trained experts from among the developers of documentation in the design, technological, design and other divisions of the enterprise (this form is preferable for large volumes of technical documentation being developed);

- by the forces of a specially created commission or a group of specialists when accepting technical (sketch, working) projects of complex products or technological objects, control systems, as well as at other stages of the development of technical documentation;

- by the forces of a group or individual specialists involved in the metrological examination under the contract.

The organization of metrological examination of draft state standards is assigned to interstate technical committees (ITC) or technical committees (TC) and their subcommittees (IPC or PC) in accordance with GOST R 1.11-99 "State standardization system of the Russian Federation. Metrological examination of draft state standards", entered into force on 01.01.2000.

Draft state standards, which set out the methods for performing measurements intended for use in the areas of distribution of state metrological control and supervision, must be subject to metrological examination in state scientific metrological centers (metrological research institutes). This examination is not carried out if the state scientific metrological center has previously certified a standardized measurement technique.

Draft state standards of the GSI, developed by state scientific metrological centers (metrological research institutes of Gosstandart), are not sent for metrological examination.

2.3. A regulatory document that defines a specific procedure for conducting metrological examination at an enterprise should establish:

- nomenclature of products (types of objects), the documentation for which must be subjected to metrological examination;

- specific types of technical documentation and stages of its development, at which the documentation must be subjected to metrological examination, and the procedure for submitting documentation for metrological examination;

- subdivisions or persons conducting metrological examination;

- the procedure for considering disagreements arising during the metrological examination;

- registration of the results of metrological examination;

- rights and obligations of experts;

- planning of metrological examination;

- the procedure for conducting an unscheduled metrological examination.

2.3.1. The list of documentation subject to metrological examination primarily includes documentation for products (types of objects) that fall within the scope of state metrological control and supervision.

2.3.2. The normative document establishing the procedure and methodology for conducting metrological examination should not indicate the requirements for metrological support and metrological requirements for technical documentation. Such requirements should be set out in other documents.

2.4. Training, advanced training of experts.

First of all, the expert must clearly understand his functions. The expert should not replace the designer, technologist, designer in the development of technical documentation, the responsibility for the quality of which lies solely with the developer. The expert is responsible for the correctness and objectivity of the conclusions based on the results of the metrological examination.

The expert must have a good understanding of the tasks of metrological examination, have the skills to solve them, and be able to highlight priority issues when considering specific documentation.

Metrological experts should have a good understanding of the content of various types of design and technological documents for specific products, the composition and content of project documentation (especially in terms of requirements for measurement accuracy, methods for monitoring and testing products and its components, and measuring instruments used).

Experts from among the developers of the documentation should have a good knowledge of the basic metrological rules, navigate in the metrological normative and methodological documents related to the objects being developed.

The metrological service of the enterprise should take care of the systematic professional development of experts.

2.5. The set of scientific and technical documentation, methodological documents and reference materials necessary for the metrological examination should include the fundamental standards of the State System for Ensuring the Uniformity of Measurements (GSI), standards of the GSI and other systems related to the documentation being developed, standards for methods of control and testing, as well as reference materials related to the developed products (objects), catalogs and other information materials on measuring instruments that can be used in the development, production and application of products (objects of development).

2.5.1. Initial information on metrological normative and methodological documents is contained in the following sources:

Index of regulatory and technical documents in the field of metrology.

Index of state standards. Publishing house of standards.

Index of the composition of sets of verification tools. VNIIMS.

Departmental reference materials.

2.6. The use of computer technology in the conduct of metrological examination.

The use of computer technology significantly increases the efficiency of metrological examination.

At present, software tools for PCs in the field of metrological support have been developed and have been used, which can be used in metrological examination. Among them are the following.

2.6.1. Automated databases (developed by VNIIMS):

- on the technical characteristics of measuring instruments that have passed state tests and are approved for circulation;

- on verification and repair work carried out by state and departmental metrological services;

- on normative-technical and reference documentation in the field of metrology;

- about standards and installations of the highest accuracy;

- about exemplary measuring instruments and verification devices;

- electronic catalogs of produced devices.

2.6.2. Automated measurement error calculation systems, including databases of all metrological characteristics of widely used types of measuring instruments (developed by VNIIMS). In such systems, in addition to the results of calculating the total measurement error, the values of the error components can be given, which will make it possible to make rational decisions when choosing measuring instruments and their operating conditions, and to make objective assessments on these issues.

2.6.3. Automated systems for assessing the technical level of measuring instruments (developed by VNIIMS). These systems contribute to the rational solution of issues in the development of measuring instruments, the need for such developments.

2.7. Planning metrological examination of technical documentation.

An important organizational issue in the conduct of metrological examination is the planning of this work.

Two expedient forms of metrological examination planning:

- indication of metrological examination (as a stage) in the development plans, production launch, technological preparation, etc. plans

- an independent plan of metrological examination or the corresponding section in the work plan for metrological support.

2.7.1. It is advisable to indicate in the plan:

- designation and name of the document (set of documentation), its type (original, original, copy, etc.);

- stage of document development;

- subdivision - the developer of the document and the deadlines for submitting it for metrological examination (if the documentation is developed by a third-party organization, then the subdivision responsible for submitting the documentation for examination is indicated);

- the subdivision conducting the metrological examination, and the period of its implementation.

2.7.2. An independent metrological examination plan is drawn up by the metrological service, agreed with the documentation developer and approved by the chief engineer (technical manager) of the enterprise.

3. MAIN TASKS OF METROLOGICAL EXAMINATION OF TECHNICAL DOCUMENTATION

3.1. An expert should keep in mind two initial questions of the metrological support of any object: what to measure and with what accuracy. The effectiveness of metrological support largely depends on the correct, rational solution of these issues. Metrological expertise should contribute to the maximum extent to the rational solution of these issues. To these two priority issues, we can add 2 more important components of metrological support: means and methods for performing measurements.

3.2. Estimation of the rationality of the range of measured parameters.

3.2.1. The measured (controlled) parameters are often determined by the original regulatory or other documents for products, technology, control systems or other objects under development.

For example, in a product-specific standard, product characteristics are specified, and in the control methods section, controlled parameters are indicated. If there are no such initial requirements, then the expert, when analyzing the range of controlled parameters, is guided by the following general provisions:

- for parts, assemblies and components of products, their control should ensure dimensional and functional interchangeability;

- for finished products (in the absence of requirements for control in the relevant regulatory or other source documents), it is necessary to ensure control of the main characteristics that determine the quality of the product, and in continuous production also the quantity of products;

- for technological equipment, systems of control and management of technological processes, it is necessary to measure the parameters that determine safety, optimal mode in terms of productivity and economy, and environmental protection from harmful emissions.

3.2.2. When analyzing the parameters to be measured and measured, the following considerations must also be taken into account.
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Status:	current
Designation:	MI 2267-2000
Russian name:	Recommendation. GSI. Ensuring the efficiency of measurements in the management of technological processes. Metrological examination of technical documentation
Text update date:	01.10.2008
Date added to database:	01.02.2009
Introduction date:	2000-07-01
Developed in:	VNIIMS Gosstandart of Russia 119361, Moscow, st. Ozernaya, 46
Approved in:	VNIIMS Gosstandart of Russia (01.01.2000)
Published in:	Gosstandart of Russia No. 2000
Scope and conditions of application:	The Recommendation establishes the definition, goals, objectives, organization of work, main types of technical documentation subject to metrological examination, execution and implementation of the results of metrological examination of technical documentation.
Replaces:	MI 2267-93
Table of contents:	1. General Provisions 2 Organization of work on the metrological examination 3 Main tasks of metrological examination of technical documentation 4 Main types of technical documentation subject to metrological examination
Is located in:

GSI. Ensuring the effectiveness of measurements in management
technological processes. Metrological expertise
technical documentation.

Instead of MI 2267-93

This recommendation establishes the definition, goals, objectives, organization of work, main types of technical documentation subject to metrological examination, execution and implementation of the results of metrological examination of technical documentation.

1. GENERAL PROVISIONS

1.2. Metrological expertise is part of the complex of works on metrological support and may be part of the technical expertise of design, technological and project documentation.

1.3. During the metrological examination, erroneous or insufficiently substantiated decisions are revealed, recommendations are developed on specific issues of metrological support.

Metrological expertise contributes to the solution of technical and economic problems in the development of technical documentation.

1.4. Metrological examination can be omitted if, in the process of developing technical documentation, metrological study was carried out by the involved specialists of the metrological service.

1.5. Metrological expertise includes metrological control of technical documentation.

Metrological control is a check of technical documentation for compliance with specific metrological requirements regulated in standards and other regulatory documents.

For example, checking for compliance with the requirements of GOST 8.417 of the names and designations of the units of physical quantities specified in the technical documentation or checking for compliance with GOST 16263, RMG 29-99 of the metrological terms used.

1.5.1. Metrological control can be carried out within the framework of standard control by the forces of standard controllers specially trained in the field of metrology.

1.5.2. Decisions of experts during metrological control are binding.

The specific goals of the metrological examination are determined by the purpose and content of the technical documentation.

For example, a specific goal of metrological examination of drawings of the simplest parts may be to ensure the reliability of measurement control with optimal values for the probabilities of rejection of control of the 1st and 2nd kind.

2. ORGANIZATION OF WORKS TO CARRY OUT THE METROLOGICAL EXAMINATION

2.1. When organizing metrological expertise, the following activities are carried out at the enterprise:

Determination of the subdivision whose specialists should carry out the metrological examination;

Development of a regulatory document establishing a specific procedure for conducting metrological examination at the enterprise;

Appointment of experts;

Training and advanced training of experts;

Formation of a set of regulatory and methodological documents, reference materials necessary for the metrological examination.

2.2. Typical forms of organization of metrological expertise:

By the forces of expert metrologists in the metrological service of the enterprise (this form of organization of metrological examination is preferable with relatively small volumes of technical documentation being developed);

By the forces of specially trained experts from among the developers of documentation in the design, technological, design and other divisions of the enterprise (this form is preferable for large volumes of technical documentation being developed);

By the forces of a specially created commission or a group of specialists when accepting technical (sketch, working) projects of complex products or technological objects, control systems, as well as at other stages of the development of technical documentation;

By the forces of a group or individual specialists involved in the metrological examination under a contract.

The organization of metrological examination of draft state standards is assigned to interstate technical committees (ITC) or technical committees (TC) and their subcommittees (IPC or PC) in accordance with GOST R 1.11-99 “State standardization system of the Russian Federation. Metrological Expertise of Draft State Standards” entered into force on 01.01.2000.

Draft state standards, which set out the methods for performing measurements intended for use in the areas of distribution of state metrological control and supervision, must be subject to metrological examination in state scientific metrological centers (metrological research institutes). This examination is not carried out if the state scientific metrological center has previously certified a standardized measurement technique.

Draft state standards of the GSI, developed by state scientific metrological centers (metrological research institutes of Gosstandart), are not sent for metrological examination.

2.3. A regulatory document that defines a specific procedure for conducting metrological examination at an enterprise should establish:

The product range (types of objects), the documentation for which must be subjected to metrological examination;

Specific types of technical documentation and stages of its development, at which the documentation must be subjected to metrological examination, and the procedure for submitting documentation for metrological examination;

Subdivisions or persons conducting metrological examination;

The procedure for considering disagreements arising during the metrological examination;

Registration of results of metrological examination;

Rights and obligations of experts;

Planning of metrological examination;

The procedure for conducting an unscheduled metrological examination.

2.4. Training, advanced training of experts.

First of all, the expert must clearly understand his functions. The expert should not replace the designer, technologist, designer in the development of technical documentation, the responsibility for the quality of which lies solely with the developer. The expert is responsible for the correctness and objectivity of the conclusions based on the results of the metrological examination.

The expert must have a good understanding of the tasks of metrological examination, have the skills to solve them, and be able to highlight priority issues when considering specific documentation.

Metrological experts should have a good understanding of the content of various types of design and technological documents for specific products, the composition and content of project documentation (especially in terms of requirements for measurement accuracy, methods for monitoring and testing products and its components, and measuring instruments used).

Experts from among the developers of the documentation should have a good knowledge of the basic metrological rules, navigate in the metrological normative and methodological documents related to the objects being developed.

The metrological service of the enterprise should take care of the systematic professional development of experts.

2.5. The set of NTD, methodological documents and reference materials necessary for the metrological examination should include the fundamental standards of the State System for Ensuring the Uniformity of Measurements (SSI), standards of the SSI and other systems related to the documentation being developed, standards for methods of control and testing, as well as reference materials related to the developed products (objects), catalogs and other information materials on measuring instruments that can be used in the development, production and application of products (objects of development).

2.5.1. Initial information on metrological normative and methodological documents is contained in the following sources:

Index of regulatory and technical documents in the field of metrology.

Index of state standards. Publishing house of standards.

Index of the composition of sets of verification tools. VNIIMS.

Departmental reference materials.

2.6. The use of computer technology in the conduct of metrological examination.

The use of computer technology significantly increases the efficiency of metrological examination.

At present, software tools for PCs in the field of metrological support have been developed and have been used, which can be used in metrological examination. Among them are the following.

2.6.1. Automated databases (developed by VNIIMS):

On the technical characteristics of measuring instruments that have passed state tests and are approved for circulation;

On verification and repair work carried out by state and departmental metrological services;

On normative-technical and reference documentation in the field of metrology;

About standards and installations of the highest accuracy;

About exemplary measuring instruments and verification devices;

Electronic catalogs of produced devices.

2.7. Planning metrological examination of technical documentation.

An important organizational issue in the conduct of metrological examination is the planning of this work.

Two expedient forms of metrological examination planning:

Indication of metrological examination (as a stage) in development plans, production launch, technological preparation, etc. plans

An independent plan for metrological examination, or the corresponding section in the work plan for metrological support.

2.7.1. It is advisable to indicate in the plan:

Designation and name of the document (documentation set), its type (original, original, copy, etc.);

Stage of document development;

Subdivision-developer of the document and terms of submission for metrological examination. (If the documentation is developed by a third party, then the unit responsible for submitting the documentation for examination is indicated);

The subdivision conducting the metrological examination and the period of its implementation.

3. MAIN TASKS OF METROLOGICAL EXAMINATION OF TECHNICAL DOCUMENTATION

3.2. Estimation of the rationality of the range of measured parameters.

3.2.1. The measured (controlled) parameters are often determined by the original regulatory or other documents for products, technology, control systems or other objects under development.

For example, in a product-specific standard, product characteristics are specified, and in the control methods section, controlled parameters are indicated. If there are no such initial requirements, then the expert, when analyzing the range of controlled parameters, is guided by the following general provisions:

For parts, assemblies and component parts of products, their control should ensure dimensional and functional interchangeability;

For finished products (in the absence of requirements for control in the relevant regulatory or other source documents), it is necessary to ensure control of the main characteristics that determine the quality of the product, and in continuous production also the quantity of products;

For technological equipment, control and management systems for technological processes, it is necessary to measure the parameters that determine safety, the optimal mode in terms of productivity and economy, and environmental protection from harmful emissions.

3.2.2. When analyzing the parameters to be measured and measured, the following considerations must also be taken into account.

Many technical characteristics of parts, assemblies, components of products are determined by the previous stages of technological processes, equipment, and tools. So the dimensions of the stamped parts are determined by the tool, so their “total” control is irrational.

It is also necessary to take into account the relationship of parameters in the technological process. For parameters that are not among the most important, this relationship can be used to reduce the number of parameters measured. For the most important parameters, this relationship can be used to improve the accuracy of measurements and the reliability of measuring systems (similar to the duplication of measuring channels).

3.2.3. When analyzing the nomenclature of the measured parameters, it is necessary to pay attention to the clarity of indications about the measured value. Uncertainty in the interpretation of the quantity to be measured can lead to large unaccounted for measurement errors. It is necessary to identify the redundancy of the measured parameters, which can lead to unjustified costs for measurements and metrological maintenance of measuring instruments.

3.2.4. In some cases, in the documentation you can find the use of measuring instruments and measuring channels of the process control system for the purpose of fixing the state of the process or process equipment (presence or absence of supply voltage, pressure in the supply network, overflowing media, etc.). Measuring instruments in these cases serve as indicators and can be replaced by appropriate signaling devices or similar devices, and measurements of such parameters may not be made.

3.2.5. Examples of assessing the rationality of measured parameters.

a) Measurement of linear dimensions during part control:

When measuring dimensions A and B, dimension C may not be measured. Measurement of size C is justified if it is necessary to control the correctness of measurements of sizes A and B.

b) Measurement of gas flow at the enterprise:

When measuring gas consumption by all consumers at the enterprise (expenses Q 1 , Q 2 , Q 3), the measurement of the total flow Q may not be performed. It is determined by the sum Q 1 + Q 2 + Q 3 . If the flow meters are of the same accuracy class, then this amount of expenses is determined more accurately than the results of measuring the flow Q at the "input" of the enterprise.

The total consumption of gas entering the enterprise can be determined by calculating the half sum of 0.5 (Q + Q 1 + Q 2 + Q 3). This result is more accurate than the measurement accuracy Q at the "input" of the enterprise or the sum Q 1 + Q 2 + Q 3 .

Such considerations should be taken into account during the metrological examination of the design of the gas flow measurement system at the enterprise.

3.3. Estimation of the optimality of requirements for measurement accuracy.

3.3.1. If the source documents (TOR, standards, etc.) do not specify the requirements for measurement accuracy, then the expert can be guided by the following provisions.

Measurement error, as a rule, is a source of adverse consequences (economic losses, increased likelihood of injury, environmental pollution, etc.). Increasing measurement accuracy reduces the size of these adverse effects. However, reducing the measurement error is associated with significant additional costs.

In the economic sense, the measurement error is considered optimal, at which the sum of losses from the error and the cost of measurements will be minimal. The optimal error in many cases is expressed by the following relationship:

where: d opt - the limit of the optimal relative measurement error;

d - the limit of the relative measurement error, for which the losses are known P and measurement costs W.

Since usually losses P and costs W can be determined only very approximately, then the exact value of d opt is almost impossible to find. Therefore, the error can be considered practically close to optimal if the following condition is met:

0.5d opt< d < (1,5 - 2,5)d опт,

where: d opt - approximate value of the boundary of the optimal relative measurement error, calculated from approximate values P and W.

Thus, when deciding on the optimality of requirements for measurement accuracy, the developer and expert should have at least an approximate idea of the size of possible losses due to measurement errors and the costs of measurements with a given error.

3.3.2. When analyzing the requirements for measurement accuracy of the most important parameters of large technological installations or other objects where measurement error can lead to significant losses, it is advisable to be guided by the provisions of MI 2179-91 “GSI. Ensuring the efficiency of measurements in process control. Optimization of measurement accuracy according to economic criteria”.

3.3.3. When the measurement error cannot cause noticeable losses or other adverse consequences, the limits of the permissible values of the measurement error can be 0.2 - 0.3 of the symmetrical tolerance limit for the measured parameter, and for parameters that are not related to the most important, this ratio can be 0, 5. With asymmetric boundaries and one-sided tolerance, the same values \u200b\u200bcan be used for the ratio of the limits of the permissible values of the measurement error and the size of the tolerance field.

3.4. Evaluation of the completeness and correctness of the requirements for the accuracy of measuring instruments.

3.4.1. The error of direct measurements of the parameter is practically equal to the error of measuring instruments under operating conditions.

With indirect measurements, the error of measuring instruments is part of the measurement error. In such cases, it is necessary to understand the methodological component of the measurement error. Typical sources of methodological errors are given in MI 1967-89 “GSI. The choice of methods and means of measurement in the development of methods for performing measurements. General Provisions".

3.4.2. Measurement error of average values (according to n measurement points) is almost times less than the measurement error at one point. The measurement error of average values (at one point) for a certain time interval is also less than the measurement error of current values due to the filtering of high-frequency random components of the measurement instrument error.

As already mentioned above, the more accurate the measuring instrument, the higher the measurement costs, including the costs of metrological maintenance of these instruments. Therefore, an excessive margin for the accuracy of measuring instruments is not economically justified.

3.4.3. When analyzing the completeness of the requirements for the accuracy of measuring instruments, it must be borne in mind that the limits of permissible error values of measuring instruments must be accompanied by an indication of the operating conditions of measuring instruments, including the operating range of the measured value and the limits of possible values of external influencing quantities that are characteristic of these measuring instruments.

3.5. Assessment of compliance of measurement accuracy with specified requirements.

3.5.1. If the measurement error is indicated in the documentation, then during the metrological examination it is compared with the specified requirements.

If there are no such requirements, then it is necessary to compare the limits of measurement error with the tolerance for the measured parameter. Above, practically acceptable ratios of the measurement error limit and the tolerance field limit for the measured parameter (0.2 - 0.3 for the most important parameters and up to 0.5 for the rest) have already been given.

3.5.2. If the measurement error is not indicated in the documentation (in the report, metrological certification materials, etc.), then the expert must, at least approximately, estimate this error by calculation. Guidelines for estimating measurement errors are given in MI 2232-2000 “GSI. Ensuring the efficiency of measurements in process control. Estimation of measurement error with limited initial information”. If there are direct measurements and sufficient initial information, then RD 50-453-84 “Guidelines. Characteristics of the error of measuring instruments in real operating conditions. Methods of calculation".

The same NTD can be used in the analysis of the objectivity of the calculated or experimental estimates of the measurement error given in the reports, metrological certification materials, etc. documentation.

In this analysis, it is necessary to keep in mind 4 groups of factors affecting the measurement error:

Metrological characteristics of measuring instruments;

Measurement conditions (external influencing quantities);

Procedures for preparing and performing measurement operations, an algorithm for processing the results of observations;

Properties of the measurement object (adequacy of the measured value to the determined characteristic of the object, energy exchange between the object and the measuring instrument, etc.).

3.6. Evaluation of the testability of the design (measuring systems).

3.6.1. Under the controllability of the design of a product (system) is understood the possibility of controlling the necessary parameters in the process of manufacturing, testing, operating and repairing products.

3.6.2. In the metrological examination, the main attention is paid to the analysis of the practical possibilities of measuring control of the necessary parameters that determine the performance of the product in the specified conditions. Attention is drawn to the accuracy of such measurements, especially in the conditions of operation and repair.

3.6.3. During the metrological examination of documentation for measuring systems, it is necessary to evaluate the effectiveness of self-control devices and subsystems, incl. subsystems for monitoring the reliability of measurement information coming from sensors.

3.7. Evaluation of the possibility of effective metrological maintenance of the selected measuring instruments.

3.7.1. When evaluating the possibility of effective metrological maintenance of the selected measuring instruments, they are guided by the methods and means of verification given in the CSI documents. For the vast majority of types of measuring instruments, the relevant documents are given in the "Index of scientific and technical documentation in the field of metrology", verification (calibration) tools are given in the "Index of the composition of sets of verification tools" (VNIIMS ed.).

3.7.2. In a number of cases, measuring instruments (sensors, etc.) are not available under operating conditions, or there are no standards for these conditions.

Control of metrological serviceability in such cases can be carried out in accordance with the recommendations of MI 2233-2000 “GSI. Ensuring the efficiency of measurements in process control. Basic Provisions” (Section 4).

3.8. Evaluation of the rationality of the chosen means and methods for performing measurements.

3.8.1. The analysis of the rationality of the selected measuring instruments is greatly facilitated if there are relevant documents on the choice of measuring instruments for specific tasks, for example, RD 50-98-86 “Selection of universal measuring instruments for linear dimensions up to 500 mm (according to the application of GOST 8.051-81)”.

3.8.2. In many cases, such documents do not exist. The expert must analyze the rationality of the selected measuring instruments, not only in terms of measurement accuracy under their operating conditions, but also in terms of the following characteristics:

Possibility of using measuring instruments in given conditions;

Labor intensity and cost of measuring operations;

The expediency of using statistical methods of control;

Compliance with the performance (inertia) of measuring instruments for the performance of process equipment, the needs of control systems at the rate of receipt of measuring information;

Satisfying safety requirements;

Labor intensity and cost of metrological service.

3.8.3. When analyzing the measurement methods specified in the documentation, preference should be given to standardized and certified methods. The expert may recommend the standardization of measurement procedures if there are appropriate prerequisites for this.

3.8.4. It is necessary to evaluate the completeness of the methods described, since uncertainty in the presentation of some operations, their sequence and calculation procedures can lead to significant measurement errors.

3.8.5. When analyzing the compliance of the measurement error with the specified values, it is necessary to pay attention to the possibility of methodological errors.

3.8.6. General recommendations on the content and presentation of measurement procedures are given in GOST R 8.563-96 “GSI. Methods for performing measurements”, general recommendations on the choice of means and methods of measurements in MI 1967-89 “GSI. The choice of methods and means of measurement in the development of methods for performing measurements. General Provisions".

3.8.7. Examples of evaluating the rationality of the chosen measuring instruments.

a) Measurement of the length of a part with a given measurement error of not more than 25 microns.

The micrometer is smooth with a reading of 0.01 mm when set to 0 on the setting measure;

Bracket indicator with a division price of 0.01 mm;

Dial indicator with a division value of 0.01 mm, accuracy class 1.

The simplest measuring instrument is a micrometer. However, with large batches of controlled parts, the use of the indicator is preferable, because. this ensures less laboriousness of measurements.

b) Measurement of the absolute pressure of saturated steam in the turbine condenser. This parameter is one of the most important for turbine control and the operation of the process control system.

The following types of sensors can be used for the measuring channel of this parameter:

Resistance thermometer (using the functional relationship between the absolute pressure of saturated steam and temperature);

Overpressure sensor, for example, Sapphire-22DI type, and barometer (for periodic input of air pressure values surrounding the sensor);

Absolute pressure sensor, for example, type Sapphire-22DA.

The temperature measurement at the installation point of the resistance thermometer is quite accurate. The instrumental error of the measuring channel is less than the instrumental errors of the measuring channels with other types of sensors. However, due to the non-uniformity of the temperature field in the turbine condenser, the measurement of the absolute steam pressure by this method is accompanied by a significant methodological component of the error.

When measuring with an overpressure sensor, there is also a methodological component of the error due to the non-uniformity of the pressure field in the turbine condenser (although this non-uniformity is much less than the non-uniformity of the temperature field). In addition, there is a methodological component of the error due to the discrete input of atmospheric air pressure values.

When using an absolute pressure sensor, methodological errors are much smaller and the highest measurement accuracy is provided. The costs of measurements, including the costs of metrological maintenance of measuring instruments, using a measuring channel with an absolute pressure sensor differ little from the costs for other options for measuring channels. Therefore, the use of an absolute pressure sensor is preferable.

3.9. Analysis of the use of computer technology in measuring operations.

Computer technology is increasingly used in measuring operations. Often computer facilities are built into measuring systems; the measuring channels of the process control system usually contain certain computer components in their composition. In such cases, among the objects of analysis in the metrological examination there should be a calculation algorithm.

Often, the calculation algorithm does not fully correspond to the function that links the measured value with the results of direct measurements (with the values of the quantity at the input of measuring instruments). Usually this discrepancy is caused by the capabilities of computer technology and forced simplifications of the calculation algorithm (linearization of functions, their discrete representation, etc.). The expert's task is to assess the significance of the methodological component of the measurement error due to the imperfection of the algorithm.

3.10. Control of metrological terms, names of measured quantities and designations of their units.

3.10.1. The correct use of terminology is the key to avoiding typical errors and ambiguities in the content of technical documentation. The metrological terms used in the technical documentation must comply with the recommendations of GOST 16263 “GSI. Metrology. Terms and definitions”, RMG 29-99 “Metrology. Terms and Definitions". Explanations of metrological terms are given in the Dictionary-reference book "Basic terms in the field of metrology" (Standards Edition, 1989). During metrological examination, special attention should be paid to the terminology in the documentation used in various sectors of the national economy (technical specifications, operational documents, etc.).

3.10.2. The names of the measured quantities can be very different. However, the documentation should contain certain information that allows one to judge the physical quantity subjected to measurements using measuring instruments “tied” to a specific verification scheme. This is necessary for an objective assessment of the selected methods and measuring instruments, the possibility of their metrological service.

3.10.3. Units of measured values must comply with GOST 8.417 “GSI. Units of physical quantities" taking into account RD 50-160-79 "Introduction and application of GOST 8.417-81", RD 50-454-84 "Introduction and application of GOST 8.417-31 in the field of ionizing radiation" and MI 221-85 "GSI. Methodology for the implementation of GOST 8.417-81 in the field of measurements of pressure, force and thermal quantities.

4. MAIN TYPES OF TECHNICAL DOCUMENTATION SUBJECT TO METROLOGICAL EXAMINATION

This part provides the main tasks of metrological examination, corresponding to the main types of technical documentation.

In the regulatory documents that establish the procedure for conducting metrological examination at specific enterprises, in addition to those given in this section, other types of documents may be indicated.

In the technical documentation of all types, the correctness of metrological terms, the designation of units of physical quantities is checked.

4.1. Technical tasks.

4.1.1. In this document, during the metrological examination, the initial data are analyzed to solve the issues of metrological support in the process of developing the design, technology, control systems and other objects for which the technical requirements are drawn up.

Two conflicting demands confront the expert. On the one hand, it is irrational to require detailed instructions and requirements for the metrological support of the object being developed in the TOR. This can significantly limit the developer in choosing rational methods and means of metrological support in the development process.

On the other hand, the TOR should contain such initial data that would allow solving the issues of metrological support at the early stages of development, without postponing them to the final stages, when there is no time and money left for significant metrological studies.

The expert must be able to find a reasonable compromise in these conflicting requirements.

If the specification specifies the nomenclature of the measured parameters, the requirements for the accuracy of their measurements, then the expert must evaluate the optimality of these requirements and the possibility of their provision.

4.1.2. The metrological examination of the TOR for the development of measuring instruments should include an assessment of the feasibility and validity of the development.

This is especially true for measuring instruments of limited use.

The expert must evaluate the possibility of verification (calibration) by the available methods and means. In their absence, the TOR should contain instructions on the development of appropriate methods and means of verification (calibration) of the developed measuring instruments.

4.1.3. If it is intended to use the developed measuring instruments in areas in which state metrological control and supervision is carried out, then the TOR should contain instructions on the need for testing and approval of the type of measuring instrument.

4.1.4. In the TOR for the development of IMS, IVK, APCS, it is necessary to check the availability and completeness of the requirements for the error of the measuring channels. The measurement channel should be understood as the whole set of technical means used to measure a parameter from the point of "selection" of information about the parameter to the scale, display screen, display screen, chart of the recording device or printout on the form. In this case, the operating conditions of the main components of the measuring channels (sensors, converters, components of communication devices with the object, computer technology) should be specified.

Instead of the requirements for the error of the measuring channels, the requirements for the measurement error can be set. Such a requirement is preferable if there are possible methodological components of the measurement error.

4.1.5. If when developing a design, technology, control systems or other object, it is supposed to develop methods for performing measurements, then in the TOR it is advisable to indicate the need for their metrological certification, and with a wide scope of application of methods for their standardization.

4.1.6. A similar analysis is performed during the metrological examination of the technical proposal, as well as applications for the development of measuring instruments, IMS and APCS.

4.2. Research reports, explanatory notes to the technical (sketch) project, test reports.

4.2.1. In the research report, the main objects of analysis in the metrological examination are the measured quantities, measurement methods (including the procedures for processing measurement results), the measuring instruments used, and the measurement error. In the reports on R&D related to the development of measuring instruments, IMS and APCS, in addition to the listed objects, it is necessary to analyze the possibilities of verification (calibration) of measuring instruments and measuring channels, the effectiveness of built-in subsystems for monitoring the performance of measuring channels and monitoring the reliability of measuring information coming from sensors. At the same time, it is estimated how much information redundancy is used, which arises due to the links between the measured parameters and multiple measurements.

A similar analysis is performed during the metrological examination of explanatory notes to technical (sketch) projects.

4.2.2. The test report usually does not set out the measurement methods and does not provide characteristics of the measurement error. In such cases, the protocol should contain references to the relevant regulatory or methodological documents.

4.3. Specifications, draft standards.

During the metrological examination of these documents, almost all the tasks of the metrological examination are solved, because specifications and many standards set out metrological requirements, methods and means of metrological support. Specifications and standards are most closely related to the original NTD; this connection and coherence should also be in the view of the expert. The following sections are subject to analysis: "Technical requirements", "Methods of control and testing", as well as the appendix (if any) "List of necessary equipment, materials and reagents".

The technical specifications and draft standards for measuring instruments also analyze the methods and means of their control during release, the consistency of these methods and means with the methods and means of verification regulated in the CSI documents.

4.4. Operational and repair documents.

In these documents, the main objects of analysis in metrological examination are the accuracy and laboriousness of measurement methods and measuring instruments used in the control and adjustment of products, control systems, products, etc. It is necessary to take into account the significant difference between the measurement conditions in operation and during repair operations from the conditions in which products are created.

It may turn out that the methods and means of measurement, which are usually set out in the technical specifications, cannot be used in the conditions of operation and repair.

4.5. Programs and methods of testing.

4.5.1. In the metrological examination of these documents, the main attention is paid to measurement methods (including processing of measurement results), measuring instruments and other technical means used in measurements, and measurement errors. When tested in laboratory (normal) conditions, the methods and measuring instruments are similar to those specified in the technical specifications. But, if the tests are carried out under operating conditions, then the methods and measuring instruments must comply with these conditions (primarily in terms of measurement accuracy).

4.5.2. It is also necessary to pay attention to the possibility of the appearance of a subjective component of the measurement error introduced by the tester (operator) and a component of the error of the test result due to inaccurate reproduction of the test mode (conditions).

If such errors are possible, then the methodology should provide for measures that limit them.

4.6. Technological instructions, technological regulations.

Technological instructions may set out methods of measurement control, measurements as part of product adjustment or adjustment operations, or make references to relevant documents. Technological regulations usually indicate the parameters subject to measurement control, the nominal values and the boundaries of the ranges of changes of these parameters (or permissible deviations from the nominal values), types, accuracy classes and measurement limits of the measuring instruments used. In some cases, the limits of permissible measurement errors are indicated.

The main objects of analysis in the metrological examination of these documents are the rationality of the range of measured parameters, the selected measuring instruments and methods, the optimality of the requirements for measurement accuracy, the compliance of the actual measurement accuracy with the required one (in the absence of requirements for measurement accuracy, compliance with the permissible deviations of the measured parameters from nominal values).

4.7. Technological maps of various types.

These documents, as a rule, do not provide detailed descriptions of metrological assurance issues. Therefore, the scope of metrological examination is much narrower than in other types of documentation given in this section, although the number of technological maps in production is very large.

In mechanical engineering industries, measurements of linear-angular quantities play an important role. A specific object of analysis in the metrological examination of technological maps and instructions in these industries are the bases from which dimensional measurements are made or which affect the accuracy of measurements.

4.8. Project documentation.

4.8.1. Almost all the main issues of metrological support are concentrated in the project documentation. Therefore, the metrological examination of project documentation should include all the tasks listed above. The volume of project documentation is often very large and experts should be well versed in the sections (volumes) of this documentation.

4.8.2. In a number of industries, the issues of metrological support are set out in a special section of the project, which, according to some metrologists, facilitates the metrological examination. However, this version of the presentation of the project may create certain difficulties in the metrological examination, because. the presentation of metrological issues is “torn off” from the objects of metrological support.

4.8.3. During the metrological examination of the project documentation of the process control system, it is necessary to pay attention to the presence and optimality of the requirements for the accuracy of measurements or measuring channels, the objectivity of the accuracy assessments and their compliance with the requirements, the rationality of the subsystem for monitoring the performance of the measuring channels and monitoring the reliability of the measuring information coming from the sensors, the use of information redundancy in order to improve the reliability and accuracy of the APCS information subsystem.

The table shows the types of technical documentation and the corresponding objects of analysis during the metrological examination (marked with +).

Objects of analysis in metrological examination	TYPES OF TECHNICAL DOCUMENTATION
Objects of analysis in metrological examination	Terms of reference, proposals (applications)	Research reports, explanatory notes to technical and draft designs	Test reports	Specifications, draft standards	Operating and repair documents	Test programs and methods	Technological instructions and regulations	Technological cards	Design Documents
Rationality of the range of measured parameters
Optimal requirements for measurement accuracy
Objectivity and completeness of requirements for the accuracy of measuring instruments
Compliance of the actual measurement accuracy with the required
Testability of a design (scheme)
Possibility of effective metrological maintenance of measuring instruments
Rationality of the chosen methods and measuring instruments
Application of computer technology
Metrological terms, names of measured quantities and designation of their units

5. FORMULATION AND IMPLEMENTATION OF THE RESULTS OF THE METROLOGICAL EXAMINATION

5.1. The simplest form of fixing the results of the metrological examination can be expert comments in the form of notes on the margins of the document. After the developer takes into account such comments, the expert approves the originals or originals of the documents.

Another typical form is an expert opinion. It is compiled in the following typical cases:

Registration of the results of the metrological examination of documentation received from other organizations;

Registration of the results of the metrological examination of sets of documents of a large volume or during the metrological examination by a specially appointed commission;

Registration of the results of metrological examination, after which it is necessary to make changes to the current documentation or develop measures to improve the efficiency of metrological support.

The expert opinion is approved by the technical manager or the chief metrologist of the enterprise.

In a number of industries, the results of metrological examination are presented in lists (logs) of comments.

5.2. Accounting for documentation that has passed the metrological examination, it is advisable to carry out in a special journal.

5.3. It must be borne in mind that the developer is responsible for the quality of the documentation, and he makes decisions based on the comments of the expert. In cases of significant disagreement between the expert and the developer, the technical manager of the enterprise makes the final decision.

The expert is responsible for the correctness of the comments and suggestions made. In a number of industry documents on metrological examination, it is incorrectly stated that the expert, along with the developer, is responsible for the quality of the documentation.

5.4. The comments of the experts, which are accepted by the developers of the documentation, serve as one of the prerequisites for improving the metrological support. Significant comments may require the development and implementation of certain activities. In these cases, the developer, together with expert metrologists, develops an action plan.

5.5. It is advisable for expert metrologists to systematically (annually or more often) summarize the results of metrological examination, identifying typical errors and shortcomings in the documentation and outlining measures to prevent them. Among such measures may be proposals for training developers on certain issues of metrological support, adjustment or development of regulatory and methodological documents used by developers. Measures can also be proposed to improve the metrological examination procedure itself.

It is also advisable to evaluate the economic effect of the metrological examination.

GSI. Ensuring the effectiveness of measurements in management
technological processes. Metrological expertise
technical documentation.

Instead of MI 2267-93

1. GENERAL PROVISIONS

1.2. Metrological expertise is part of the complex of works on metrological support and may be part of the technical expertise of design, technological and project documentation.

1.3. During the metrological examination, erroneous or insufficiently substantiated decisions are revealed, recommendations are developed on specific issues of metrological support.

Metrological expertise contributes to the solution of technical and economic problems in the development of technical documentation.

1.4. Metrological examination can be omitted if, in the process of developing technical documentation, metrological study was carried out by the involved specialists of the metrological service.

Metrological control is a check of technical documentation for compliance with specific metrological requirements regulated in standards and other regulatory documents.

For example, checking for compliance with the requirements of GOST 8.417 of the names and designations of units of physical quantities specified in the technical documentation or checking for compliance with GOST 16263, RMG 29-99 of the used metrological terms.