In which the source of information is identified, the type, serial number and installation location of the PIP are used. In order to verify the legitimacy of the measuring instruments used, the dates of the next verification of the heat meter and its measuring components, as well as the beginning and end of the metering unit’s admission to operation, are entered into the system database. For use as criteria for the reliability of measurement results, the system database stores valid values upper and lower limits of pressure, flow and temperature measurement ranges, as well as flow and temperature differences for each type of measuring component and each pipeline on which the component is installed. In general, the system uses 52 different parameters, including to validate the results of measuring the amount of heat and coolant parameters.

The implementation of control methods based on checking the authentication, adaptability and security functions embedded in the verification methodology has made it possible to reduce the verification time of the system, which currently includes about 7,000 measuring channels, from several months to several days with a corresponding reduction in the cost of verification.

Approaches to authentication, adaptability and security of the information part of large energy accounting systems

resources discussed above are proposed in the form of requirements for metrological support of AIIS KUTE for a similar purpose and are included as an appendix to the one approved for voluntary use national standard, developed at the Tomsk Center for Medical Sciences (date of introduction: March 1, 2013)

Literature

1. MI 3000-2006. GSI. Automated information and measuring systems for commercial metering of electrical energy. Standard verification procedure.

3. GOST R 8.596-2002. GSI. Metrological support of measuring systems. Basic provisions.

4. GOST R 8.778-2011. GSI. Thermal energy measuring instruments for water heating systems. Metrological support.

Date of acceptance: 08/30/2012

Calibration of measuring channels of measuring systems after their calibration

A. A. DANILOV, Y. V. KUCHERENKO

Federal Budgetary Institution "Penza CSM", Penza, Russia, e-mail: [email protected]

The issues of determining the parameters of the conversion function of measuring channels of measuring systems, introducing corrective corrections and subsequent assessment of their metrological characteristics are considered.

Key words: measuring systems and channels, metrological characteristics, conversion function.

The problems of determination of the transformation function parameters of measuring channels in measuring systems, of inserting corrections and subsequent evaluation of their metrological characteristics are considered.

Key words: measuring systems and channels, metrological characteristics, transformation function.

When conducting periodic checks of the state of metrological support (MS) of operating measuring instruments (MI), in order to increase their accuracy, the SI conversion function is calibrated with the subsequent introduction of corrective amendments. In cases where the calibration of measuring instruments (Fig. 1) is one of the stages of their calibration (or verification, which is essentially the same calibration, but with the adoption of a conclusion about the compliance of metrological characteristics (MC) with established standards), one has to take into account some features of MO SI. On

rice. In Fig. 1, a dark background highlights the chain of procedures performed sequentially, which will be discussed below.

It is known that it is advisable to carry out calibration and calibration of measuring instruments using different (at least two) copies of working standards (WE). As an example of relatively few measuring instruments for which a similar procedure is implemented, we can cite electronic balance, the delivery set of which includes a calibration weight. In this case, the MX of the balance is determined using weights from another set.

Comparison of MX with established standards (verification)

Considering that, along with the use of different copies of the standard, several options for using the same copy of the RE can be recommended for both calibration and calibration of SI. Unfortunately, in practice this cross-validation method is usually not used, which reduces the reliability of calibration and verification of measuring instruments. The fact is that the same copy of the manual, used for both calibration and calibration,

may give too optimistic results for the MX of the calibrated SI if a point rather than an interval error estimate is used. That is why we must not forget that the MX SI for which calibration is carried out should include the following estimates:

non-excluded systematic error (NSE);

standard deviation of random error;

variations.

At the same time, the assessment of the NSP SI, of course, should also include the error of the same name (which is sometimes forgotten).

If the calibration and calibration of the measuring channels (MC) of the measuring systems are supposed to be carried out as a complete set, then, most likely, they will be performed under the operating operating conditions prevailing at the time of the experiment. It should be noted that the issue of carrying out complete calibration of IR has not been methodically worked out. The question remains: how to extend the MX estimates obtained for the current operating conditions of the IC to arbitrary conditions? In addition, for complete calibration, it is advisable to use multifunctional calibrators, which should be small-sized, lightweight, mobile, with little time spent on preparation for work, maintaining their properties in a wide range of operating conditions. Often it is the last requirement for standards that is decisive and does not allow the use of calibrators in the operating conditions of IR measuring systems.

In this regard, the complete calibration has to be replaced with an element-by-element calibration: the primary measuring transducer (PMT) is turned off and the remaining part of the IC, which usually represents a complex component (CC) along with the communication line, is calibrated.

When calibrating the IR element by element, significant attention should be paid to the placement of the RE. On the one hand, its location at the place of operation of the PIP (Fig. 2, a) does not allow reducing the requirements for electronic equipment in terms of preserving the mechanical properties in the operating conditions of the PIP operation, and in some cases, solving the issues of intrinsic safety and explosion protection. On the other hand, the location of the RE at the place of operation of the CC (Fig. 2, b) leads to a violation of the symmetry of the communication line (which was the case when the PIP was connected), and, consequently, to an increase in the error component from the impact of longitudinal and transverse interference on the communication line. A third option is also possible (Fig. 2, c), which consists of element-by-element testing of PIP, CC and communication lines using communication line testing tools (CPLS).

MO procedures for operating instruments

Graduation No

MX determination (calibration) No Yes No

Rice. 1. MO procedures for operating instruments

It should be noted that the issue of calibrating the IR after calibration of its components has also not been methodically worked out. There are three options here: complete graduation and calibration; calibration and calibration of each IR component, and then calculation of their MC;

imitation of complete graduation and calibration. The first option is rarely implemented in practice, so let’s consider the second and third options and start with graduation. We will consider the calibration of each component of the IC (second option) under the assumption that a simple IC consists of series-connected PIP and CC, which have nominal linear conversion functions (TF):

where Unom, ^ X Y azhom, °zhom - the nominal values ​​of the output quantities and the values ​​of the input quantities, as well as the coefficient

Rice. 2. Methods for experimental testing of complex components (CC) and communication lines during element-by-element calibration of IR measuring systems: PIP - primary measuring transducer; RE - working standard; SPLS - line checking tools

The factors of the nominal linear FP are PIP and CC, respectively.

Let us also assume that, in order to obtain corrections, independent experimental studies of PIP and CC were carried out at several points in the measurement range, and then the FP of each of them was approximated, for example, by a polynomial of the second degree

y = a0 + a1x + a2x2; z = bo + biy + b2y2,

where a, b[ are the coefficients of the polynomials.

Let us assume that the calibration has been completed, and the expression for r, after substituting the expression for y into it, takes the form

r = b0 + b1(a0 + a1x + a2x2) + b2(a0 + a1x + a2x2)2. As a result, after transformations we get

g = c0 + c1x + c2x2 + c3x3 + c4x4,

where c0 = b0 + b1a0 + b2 a2; c0 = b1a1 + 2b2a0a1; c2 = a2 + 2b2a0a2 + + b2 a 1; C3 = 2b2a1a2; C4 = b2 a2.

Let the nominal FP IR have the form

g = c + c x nom 0nom 1nom "

then the expression for calculating the correction should be

V = r - *.„..

indications corresponding to each of the IR points being checked, which are used for calibration. Of course, a complete simulation of a complete IR calibration is not possible, since experimental studies of PIP are usually carried out under normal operating conditions, which may differ significantly from actual conditions, which reduces the reliability of the calibration.

Let us assume that the IR calibration has been carried out. Next, there are four possible options for assessing their mechanical characteristics: based on the results of calibration or subsequent calibration - complete, element-by-element or simulated complete.

Of course, the first option, despite its wide distribution, has less reliability, since when evaluating MC IR measuring systems, it is necessary to take into account the standard’s standard’s non-reactive value twice - when determining both the confidence limits of the measurement results and the correction. As noted above, the option of complete calibration with the participation of a second copy of the standard is rarely used in practice, although it has greater reliability compared to the first option. Therefore, you have to use element-by-element calibration or computer simulation

,58.45kb.

Exam questions for the discipline “Measuring technology”, 40.7kb.

Methodology for acceptance from commissioning into operation of information-measuring channels, 235.63kb.

Department of metrological support for measurements of physical and chemical quantities, 18.17kb.

Work program of the discipline measuring devices of control systems, 448.87kb.

Analysis and synthesis of measuring transducers with a frequency output signal for information-measuring, 675kb.

Verification of channels of measuring systems

Recently, problems associated with verification, in general, and with verification of channels of measuring systems, in particular, have become more and more clearly visible. Leaving aside general problems, let us dwell on issues related to the verification of channels of measuring systems.

Several such questions can be identified.

1. Should the concept of “verification” be clarified in relation to the channels of measuring systems?

2. Are the verification procedures currently used to assess the main error of the channels of measuring systems sufficiently complete?

3. How should the results of verification of channels of measuring systems be documented?

4. How to ensure mutual recognition of the results of verification of channels of measuring systems within the country and abroad?

I would like to immediately make a reservation that within the framework of this report the personal point of view of the author is presented, based on his experience in solving similar problems, and, basically, this experience was reduced to solving issues of the general organization of verification, and not methods of verification of individual specific systems. Naturally, this experience cannot be considered comprehensive, and the conclusions obtained cannot be considered indisputable.

Let's start with a number of quotes from GOST R 8.596. First of all, let's define: what is a measuring system? “Measuring system is a set of measuring, connecting, computing components forming measuring channels, and auxiliary devices (components of the measuring system), functioning as a single whole, intended for:

– obtaining information about the state of an object using measurement transformations in general case sets of quantities varying in time and distributed in space that characterize this state;

– machine processing of measurement results;

– registration and indication of measurement results and the results of their machine processing;

– converting this data into system output signals for various purposes.”

– IS-1 measuring channels, as a rule, are subjected to a complete verification, during which the metrological characteristics of the IS measuring channels as a whole (from input to channel output) are monitored;

– IS-2 measuring channels, as a rule, are subjected to component-by-element (element-by-element) verification: dismantled primary measuring transducers (sensors) - in laboratory conditions; the secondary part - a complex component, including communication lines - at the installation site of the IC while simultaneously controlling all influencing factors acting on the individual components. If specialized portable standards or mobile reference laboratories are available and IS-2 inputs are accessible, complete verification of IS-2 measuring channels at the installation site is preferable.”

In this case, the channels IS-1 and IS-2 mean the following:
“IS-1 – products produced by the manufacturer as complete, complete (except, in some cases, communication lines and electronic computers) products, for installation of which at the site of operation the instructions given in the operational documentation, which standardizes the metrological characteristics of the system’s measuring channels, are sufficient;

IS-2 are designed for specific objects (groups of standard objects) from IC components, produced, as a rule, by various manufacturers, and accepted as finished products directly at the operation site. The installation of such ICs at the site of operation is carried out in accordance with the design documentation for the IC and the operational documentation for its components, which standardizes the metrological characteristics of the measuring channels of the IC and its components, respectively.”

Let's consider the simplest example - a heat meter. It fully complies with the definition of a measuring system. However, for its verification, GOST R 51649 recommends different approaches to verification: element-by-element and channel-by-channel. The element-by-element method is recommended to be used when the components of the heat meter are approved as types of measuring instruments, as well as when there is a standard information connection between the parts and a duly approved method for calculating the error of the heat meter based on the errors of its components.

The channel-by-channel method is used when channel error standards have been established and there is a method for calculating the error of a heat meter based on the errors of its measuring channels, approved in the prescribed manner.

It is interesting to note that in the same GOST R 8.596, a measuring channel is understood as “a structurally or functionally distinguishable part of an IC that performs a complete function from the perception of the measured quantity to the receipt of the result of its measurements, expressed as a number or a corresponding code, or until analog signal, one of the parameters of which is a function of the measured quantity.

Note . IC measurement channels can be simple or complex. In a simple measuring channel, the direct measurement method is implemented through successive measuring transformations. A complex measuring channel in the primary part is a combination of several simple measuring channels, the signals from the output of which are used to obtain the result of indirect, cumulative or joint measurements or to obtain a signal proportional to it in the secondary part of the complex measuring channel IC.”

It follows that the heat meter should be considered as a complex measuring channel, but consisting of a number of simple ones. It seems that we are somewhat confused. Even on this simple example, it turns out that the same measuring instrument can be considered both as a system and as a channel.

But let's get back to verification. By definition, the heat meter should be classified as IS-1, and, therefore, it should be verified comprehensively, but currently there are no such methods. If an element-by-element or channel-by-channel verification method is used, which in in this case is not significant, then, in some cases, periodic verification comes down to an external inspection. At external inspection the following operations are performed:

– assessment of compliance of the heat meter completeness with the passport;

– checking the availability of unexpired verification certificates (or other documents confirming the passage of primary or periodic verification) of the heat meter and each of its components;

– monitoring the presence and integrity of the manufacturer’s seals, as well as seals and stamps required for commercial accounting instruments;

– checking the absence of mechanical damage affecting the performance of the heat meter’s components and electrical connections between them.

The list of operations given above is essentially a verbatim quote from the methodology of one of the heat meters.

It turns out that during periodic verification no work is performed to assess the metrological characteristics of the heat meter. Such work is carried out during verification of its components. Then verification degenerates into a purely administrative procedure. This leads to two questions at once:

1. Perhaps we can define verification as an assessment of the compliance of measuring instruments with established technical and administrative requirements? In this case, metrological characteristics, which are part of the technical ones, can be established during the calibration process.

2. Is the set of procedures performed during periodic verification sufficient to be sure that the main error of the heat meter as a whole will not exceed the standardized limits? Without developing this topic further, it can be noted that the listed set of procedures does not include checking the correctness of the connections. And this can have a very significant impact on the total error.

It would be possible to note other sources of errors, which are often not taken into account when describing methods for verifying measuring systems. Let us also note only the possibility of influence software on the reliability of the results obtained. Despite the fact that considerable attention is paid to this issue abroad. In Russia, work in this direction is just beginning. Issues related to the influence of interfaces, both digital and especially analog, on the reliability of the obtained measurement results are very poorly reflected in the methodological and regulatory documentation.

And also about the problems of mutual recognition of verification and calibration results not only within the CIS, which may also become a significant problem in the near future, but also in so-called foreign countries.

In Russian metrological practice, several related concepts are used that relate to technical devices used in the field of metrology:

A standard sample is a technical device in the form of a substance (material) that establishes, reproduces, stores units of quantities characterizing the composition or properties of this substance (material) in order to transfer their size to measuring instruments;

Measuring instrument – ​​a technical instrument intended for measurements, having standardized metrological characteristics, reproducing and (or) storing a unit of quantity, the size of which is taken unchanged (within the established error) over a known time interval;

Control means – a technical means that reproduces and (or) stores a value given size, designed to determine the state of the controlled object and having standardized error characteristics;

Test equipment is a technical means designed to reproduce and maintain test conditions.

If any of the listed technical devices are used in areas covered by legal metrology, for example, safety, health, trade, ecology, etc., should it be subject to testing and type approval requirements or does this only apply to measuring instruments in strict understanding of this term? In Germany, for example, this distinction is not so strict, and in our country, in practice, a significant share of the State Register of Measuring Instruments consists of control devices and testing equipment.

If a measuring instrument consists of separate units that can be used either autonomously or as part of complex measuring devices or channels of measuring systems, should each of such units be tested and type approved separately? If so, can a channel of a measuring system, which includes similar blocks that have not been individually type approved, be approved as a separate type of measuring instrument?

A number of international documents on metrology indicate the possibility of refusing testing and type approval of measuring instruments if their compliance with existing requirements can be confirmed on the basis of the submitted technical documentation, and the metrological characteristics are assessed during initial verification or calibration. Should it be clarified which specific groups of measuring instruments are covered by this provision?

If a measuring instrument is manufactured or imported in a single or small number of copies, is it necessary to carry out type approval work or is it sufficient to carry out an initial verification (metrological certification) of specific samples?

If the metrological characteristics of a measuring instrument significantly depend on the conditions and quality of installation and adjustment of the measuring instrument, which is the case when creating measuring systems of the IS-2 type, does type approval make sense in this case?

Confirmation of the compliance of an individual sample of a measuring instrument with the approved type can be implemented in the form of verification or calibration. In this case, a distinction is made between primary and subsequent verification.

The difference between verification and calibration is, on the one hand, that during calibration the actual values ​​of the metrological characteristics of measuring instruments are established, and during verification only their compliance with the established requirements is determined. On the other hand, these two procedures differ in status. Verification is carried out in those areas of measurements that are subject to state regulation. Calibration can be done in these areas and beyond. Essentially, calibration, in most cases, serves as an integral part of verification.

If the measuring instruments have not been tested for the purpose of type approval, then the content of the initial verification is significantly expanded. In this case, there is a need to confirm that the measuring instrument complies with all legal metrology requirements for such measuring instruments. Therefore, in addition to certain tests (controls), the manufacturer's data, his declaration of conformity and, in some cases, his quality assurance system must also be used. Simple control technical characteristics in this case it is not enough.

In both the first and second cases, the initial verification can be selective.

Thus, it is necessary, firstly, to determine the requirements for various types of measuring instruments. OIML recommendations, IEC and ISO standards, and annexes to European Directive 2004/22/EC can be taken as a basis. The development of such documents is not yet expected.

Secondly. In the presence of the specified documents defining the agreed requirements for measuring instruments, it is possible to raise the question of using OIML Certificates as a document confirming compliance with a certain type, but so far this approach is not supported even at the level of regional metrological organizations.

Third. If measuring instruments of the same type are produced by different manufacturers or are available in different modifications, then confirmation is required that they all correspond to the approved type.

Fourthly, it is required to ensure a correct assessment that each individual measuring instrument corresponds to the approved type. Those. it must be properly verified or calibrated.

The task of primary verification (calibration) is the need to prove with acceptable reliability that each instance of a measuring instrument in production, and for measuring systems in installation and commissioning, meets the technical characteristics requirements established in the type description.

This confirmation can be used:

– individual control of each unit of measuring instruments;

– statistical (sampling) control of independent samples;

– statistical (sampling) control of successive samples;

– statistical control of the technological process using control charts;

– use of the manufacturer’s quality assurance system.

Moreover, for measuring systems only the first and last approaches are feasible.

Verification or calibration of measuring instruments can be carried out in the country that produces the measuring instruments, as well as in the importing country. Often calibration must be performed on site after the measuring instruments have been installed. Methods for performing verification (calibration) when meeting general requirements for the nomenclature of the evaluated characteristics of measuring instruments and the reliability of the results obtained may vary, taking into account the technological capabilities of different countries. This creates additional difficulties for mutual recognition of verification and calibration results.

These problems prevent a quick solution to the issue of mutual recognition. Perhaps consideration should be given to developing a document that would define the criteria for selection rational way carrying out initial verification (calibration) in each specific situation.

This document may also define the conditions necessary for the conclusion of agreements on mutual recognition of the conformity of measuring instruments with agreed requirements for them between national legal metrology authorities of different countries.

Literature

1. GOST R 8.596-2002. GSI. Metrological support of measuring systems. Basic provisions

2. GOST R 51649-2000 Heat meters for water heating systems. General technical conditions

Lukashov Yuri Evgenievich – head of department of FSUE “VNIIMS”, Ph.D., Associate Professor

Russia, 119361, Moscow, Ozernaya, 46

The material is devoted to an important aspect of metrological support for ready-made automation systems - calibration of measuring channels (MC) of automated process control systems, namely: the problem of increasing the efficiency of calibration work and reducing their labor intensity due to a more effective calibration method.

The modern automated process control systems (APCS) created today for large thermal power facilities are characterized by high complexity and degree of responsibility. Software and technical complexes (PTK), which form the basis of automated process control systems, must not only ensure the implementation of all the functions of monitoring, measuring and regulating technological parameters that are necessary today, but also be convenient and technologically advanced in operation and maintenance. One of the important types of support for ready-made automated systems is metrological support.

It is no secret that metrological issues are the most “sick” and “unloved” for both many hardware systems suppliers and operational services. Often, metrology issues are completely ignored, especially in connection with the introduction of microprocessor control systems. True, this method of solution requires a certain loyalty on the part of standardization and metrology bodies. Otherwise, problems in solving metrological problems can result in serious problems and significant production and economic losses.

Using the experience of implementing automated process control systems and their support, the company “ ” has developed an integrated approach to creating modern systems at generating energy facilities. Together with leading design and technological organizations, the company carries out all the necessary research and engineering work. Particular attention is paid to metrological support of supplied automated control systems.

Necessary metrological work is carried out at each stage life cycle APCS. At the technical specification stage, requirements for metrological support of the developed system are formed, at the technical project stage, lists of measuring channels (MC) are developed, requirements for the accuracy of measurements are determined, measuring instruments are selected for the formation of MC, providing the required accuracy, and working standards are also selected, using which can confirm the specified measurement accuracy. At the stage of preparation of working documentation, coordination with the Customer is carried out on the use of methods for verification (calibration) of measuring channels approved by the State Standard of the Russian Federation.

At the stage of putting the automated process control system into operation, a set of metrological works is carried out in accordance with regulatory documents.

At the commissioning stage, installation and adjustment of the system's measuring channels are carried out; at the preliminary testing stage, the commissioning organization, together with the personnel of the operating organization, accepts the IC from commissioning into trial operation in order to check the compliance of the IC and readiness for commissioning. All measuring channels of the system are subject to initial verification or calibration.

At the acceptance testing stage, tests can be carried out for the purpose of “certification of conformity” of the IC, or tests for the purpose of type approval. And finally, in industrial operation, periodic verification or calibration of the measuring channels of the automated process control system is carried out.

They form the basis for the automated process control systems being created, are developed in accordance with the regulatory documents of the Russian Federation and belong to the products of the State Instrumentation System. PTK “Tornado” is included in the State Register and has a certificate of approval of the type of measuring instruments.

The methods for verification (calibration) of the measuring channels of automated process control systems and measuring modules that are part of the software and hardware complex, developed by the company's metrological service, were approved by the All-Russian Research Institute of Metrology and Standardization (VNIIMS).

In addition to the necessary documents and hardware, the company offers its Customers specialized software “Metrologist’s Workstation” (the company’s own development), which is an integral part of the PTK “Tornado” software and allows calibration of the measuring channels of the automated process control system in an automated mode.

The developed methods for calibrating the measuring channels of automated process control systems are supplied complete with specialized software and hardware. In our opinion, this method is one of the most optimal for solving metrological issues when implementing automated process control systems. However, today the company’s specialists are working on the problem of reducing labor costs for calibrating ICs supplied to the customer of automated process control systems. According to the currently existing method, at least two people are involved in the process of calibrating the channels of the automated process control system at the facility. One of them is located at the stationary workplace of an automated process control system engineer or a metrologist and works with the “Metrologist’s Workstation” program. The second should be located at the junction boxes in order to use the reference signal generator to supply a reference signal at the point where the primary transducer (sensor) is connected. Both calibrators must be equipped with radios to coordinate their actions. After the initial data about the channel is entered, the number of sections of the measurement range in which measured values ​​will be collected is specified, the program determines the value of the reference signal and prompts at what moment this signal can be applied to the IR input. The calibrator working at the computer must pass this information on to his colleague who is on site (Fig. 1).

Rice. 1. One of the existing methods for calibrating IR automated process control systems

Thus, the existing methodology implements the traditional (using VT tools and specialized software) calibration (verification) method, which has a number of disadvantages:

Large time costs (calibration of each channel requires 10-15 minutes, excluding the time spent on connecting the reference signal generator);

The need for two people to participate in the calibration process;

Possibility of erroneous information;

Manual controller control;

Information is transmitted via radio.

The disadvantage of the user interface of a stationary metrologist's workstation is the need to manually enter process settings when checking each channel (channel accuracy class, measurement range sections, units of measurement, etc.).

The fundamental disadvantage of the existing IR calibration technique is that the calibrator working on site is constantly busy during the calibration process and cannot be distracted by the work of preparing the next channel at the time of calibrating the current channel. That is, according to the existing methodology, the calibrator works strictly sequentially - preparing the channel for calibration (5-10 min), calibration (10-15 min), restoring the channel (5-10 min). In total, the entire process takes an average of 30 minutes per channel. Thus, 10-15 channels can be calibrated in one shift. If we take into account that all this work is carried out by daytime staff, and the volume of IRs to be calibrated at a 200 MW power unit is about 2000, then calibrating all IRs will take from 6 to 9 months! This is, of course, if everything is done honestly.

Therefore, if there are loopholes, and there is an opportunity not to do so, then in the vast majority of cases, no one is involved in metrology as such - neither the process control system supplier, nor the operational services.

As already mentioned, the Tornado software package includes a comprehensive solution to metrological problems, but, unfortunately, the labor intensity of this work remains high. And the company’s specialists realized from their own experience that it was necessary to radically change the situation and reduce the labor intensity of calibration work.

To create a more effective calibration method that does not have the disadvantages of the previous system and can significantly increase the work efficiency of a calibrator due to greater automation of the process of collecting measurement information and processing results, the company’s specialists needed to carry out a number of theoretical and research works:

Development of a new calibration method;

Analysis of required hardware and equipment selection;

Development of optimal architecture new system calibration;

Calculation and creation of a test model of a mobile workstation for a metrologist;

Development of an operator interface for mobile and stationary workstations;

Development of new communication protocols.

After carrying out the work, the company’s specialists came up with the idea of ​​using wireless technologies communications for organizing calibration work.

Development of a new calibration method

The developed method involves sequential execution of the following operations:

Disconnecting the sensor and connecting the reference signal generator to the input of the measuring channel;

Selecting a channel by its code or name on the metrologist’s mobile workstation. In this case, a request is sent from the mobile workstation to the stationary workstation, where all the necessary information about this channel is selected from the database or from the list of ICs: measurement range, channel accuracy class, information about the sensor, measuring module and other information necessary to organize the process calibration and for inclusion in the certificate;

Launching an automatic procedure for collecting measured values ​​and statistical processing of the sample;

Monitoring the calibration process, viewing results.

During the automatic execution of the calibration process, the calibrator has the opportunity to monitor on the mobile workstation the current measured value, the deviation of this value from the reference value, and the switching of generated values. It is also possible to view the calibration protocol and certificate for the channel.

Equipment selection

The company's specialists studied the specific features of the IR calibration process at large industrial facilities and formulated fundamental criteria for determining the composition of the technical means of the new system:

Communication range and speed characteristics. When choosing wireless communications, important criteria are communication range and speed characteristics. This criterion is directly related to the design features of an industrial facility, namely: the geometry of the premises, the presence of metal structures, and the presence of interference.

Full-scale tests of the new system were carried out at Novosibirsk CHPP-5;

Compatibility of physical interfaces. Please note that all devices must be compatible with each other at the level of physical interfaces, and also be supported at the operating system (OS) level;

Weight and dimensions of the components used. All devices included in a mobile workstation must meet the requirements of mobility and ease of use. That is, have minimal weight and dimensions for the unimpeded movement of a calibration specialist around the facility together with a mobile workstation;

Optimal power supply. Low power consumption, mobility, the ability to use a common autonomous power source;

Cost-effective implementation. The requirement concerns the acceptable cost and feasibility of implementation on site, subject to all the above criteria.

System architecture development

Rice. 2. General structure of the IR ACS calibration system

The structure of a distributed system for calibrating measuring channels was determined taking into account the specifics of calibrating measuring channels at large industrial facilities. The system is based on the idea of ​​using wireless communication technologies, mobile computer and a reference signal generator controlled from it. A radio modem is connected to the stationary workstation computer (Fig. 2), the necessary changes are made to the stationary workstation program to operate in the remote control mobile workstation.

The mobile workstation of a metrologist includes:

1_pocket personal computer (PDA), which performs two functions:

Remote interface to the metrologist’s stationary workstation;

Transfer of tasks received from a stationary workstation of a metrologist to a programmable master.

2_Programmable controller, with the help of which a calibration signal is generated at the channel input.

3_Block for providing wireless communication between a PDA and a stationary workstation.

4_Means that provide power to the radio modem and analog signal generator.

Creation of a test model of a mobile workstation for a metrologist

After tests and analysis comparative characteristics range of industrial laptops and pocket personal computers It was decided to use a PDA as a computer for the test model of the workstation.

As a unit for providing wireless communication between a PDA and a stationary workstation in a test model of a mobile metrologist's workstation, a radio modem was used with the modem powered from battery 12 V.

Unlike WI-FI devices operating at frequencies of 2400 - 2483.5 MHz, the radio modem operates at a frequency of 433.92 MHz and is optimally suited for industrial facilities such as thermal power plants.

Rice. Connecting the controller to the PDA

Radio waves with a frequency of 433 MHz better bend around metal structures of typical (for an industrial enterprise) sizes. In a workshop environment, metal structures are partially bent by radio waves, and the wave partially hits obstacles due to reflections.

The spatial attenuation of radio waves at low frequencies is less. The radio modem used is specially adapted for operation in conditions of pulsed interference, since it uses concatenated interleaved coding, which effectively corrects errors during data transmission.

As a programmable master, with the help of which a reference signal is generated at the channel input, a programmable calibrator-meter of unified signals IKSU 2000 was used. The advantage of this master is its high accuracy class, which allows it to be used not only for calibrating IR, but also PTC measuring modules , the accuracy class of which is significantly higher.

The transmitter is lightweight and small in size. It is possible to program the calibrator via the RS232 interface. The calibrator can be powered by a 12V battery; this makes it possible to use one source to power the calibrator and the radio modem.

The IKSU 2000 calibrator is connected to the PDA via a cable.

The use of the IR-RS232 device (infrared port - RS232), as one of the components of a mobile workstation, was determined based on the need to control two devices with a PDA. This made it possible to use it as a transparent IR-RS232 communication channel and power from the connected device via the RS232 interface.

The radio modem connects to the PDA via IR port-RS232.

Thus, all components of the mobile workstation are freely placed in a volume of 350x250x100 mm and have a total weight of no more than 2.5 kg.

Results of the work carried out

As a result of the work carried out, a test model of a working system (including a mobile workstation and a program for a stationary workstation) was created for calibrating measuring channels various types. All necessary changes were made to the software of the stationary workstation to operate in remote control mode.

A number of tests carried out at CHPP-5 of Novosibirskenergo OJSC showed that:

During the calibration process, when using the new distributed calibration system for measuring channels, the participation of only one person equipped with a mobile metrologist’s workstation is sufficient. All control of the controller falls entirely on the program of the stationary workstation, which eliminates errors associated with the installation of the device. Instructions are received via wireless communication into the program installed on the mobile workstation, which controls the calibrator. The entire process is controlled from a mobile workstation, also via a wireless connection;

The functions of the calibrator - coordinator of the mobile workstation include: starting the process and selecting the channel code (the necessary initialization is carried out on the stationary workstation); visual monitoring of the process progress through the mobile workstation software interface, which displays the current stage of calibration, the values ​​of the current measurement errors, and the set values ​​on the setpoint. The calibrator has the ability to stop the calibration process at any time or start the procedure from the very beginning;

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• Table of contents
• Introduction
• Terms and Definitions
• 1. Verification and calibration of IIS
• 1.1 General provisions
• 1.2 Methods for monitoring metrological characteristics
• 1.3 Method for determining error
• 1.4 Problems and solutions in the field of verification and calibration of electronic information systems
• 2. Organization of quality assurance work at the enterprise FBU "Sakhalin CSM"
• Conclusion
• Bibliography
• Introduction
• Today, metrological activities are regulated by the Law of the Russian Federation “On Ensuring the Uniformity of Measurements”. It follows from this that this activity is included in the general system of law and, on the one hand, has its own specific norms, on the other hand, it must interact closely with common system public administration and the state system of generally binding norms.
• The public function requires public administration. In turn, control is implemented in a specific system. Such a system is a national measurement system, which includes all participants in the measurement business - developers, manufacturers and users of measuring instruments. To achieve the uniformity of measurements, conditions are created for the functioning of the “state system for ensuring the uniformity of measurements” (GSI). The most important link in this system is “legal metrology”. Formally, this term denotes a section of metrology, including sets of interrelated and interdependent general rules, requirements and standards, as well as other issues that require regulation and control by the state, aimed at ensuring the uniformity of measurements and the uniformity of measuring instruments.
• On January 1, 2009, the new Law of the Russian Federation “On Ensuring the Uniformity of Measurements” came into force, which became an act with the highest legal force in the areas of measurement. He established the regulation of the most important relations. Under these conditions, the specification of the main provisions of the Law is entrusted to acts of lawmaking - by-laws or regulatory documents of legal metrology.
• Real the federal law regulates the relationships that arise when performing measurements, establishing and complying with requirements for measurements, units of quantities, standards of units of quantities, standard samples, measuring instruments (hereinafter referred to as SI), the use of standard samples, measuring instruments, measurement techniques (methods), as well as in the implementation of activities to ensure the uniformity of measurements provided for by the legislation of the Russian Federation on ensuring the uniformity of measurements, including when performing work and providing services to ensure the uniformity of measurements.
• One of the types of measuring instruments are measuring systems (hereinafter referred to as IS) and they are subject to all General requirements to measuring instruments.
• The activities of metrological services for metrological support of IS are regulated by documentation, GOST R 8.596-2002 (the main document for metrological support of IS), GOST 27300, as well as , , , , , , and others, in which it is established
• Metrological support of IS includes the following activities:
• - standardization, calculation of metrological characteristics of IC measuring channels;
• - metrological examination of technical documentation for IP;
• - IP testing for type approval; IP type approval and testing for compliance with the approved type;
• - IP certification;
• - verification and calibration of IS;
• - metrological supervision over the production, installation, adjustment, condition and use of IS
• Sometimes, in order to obtain information about the parameters of an object, it is necessary to carry out complex measurements, and the value of the measured quantity is obtained by calculation based on known functional relationships between it and the quantities being measured. These problems are successfully solved with the help of information measurement systems (hereinafter referred to as IMS), which have become widespread. Currently, there is no generally accepted unambiguous definition of what IIS is. Among the existing approaches to considering the concept of IIS, two main ones should be highlighted. The essence of one approach is reflected in the recommendation for interstate standardization RMG 29-99 "GSI. Metrology. Basic terms and definitions", where IMS is considered as a type of measuring system (MS).
• In practice, the term “measuring information system” is almost universally used, which, according to a number of prominent metrologists, incorrectly reflects the concept of a measuring information system.
• When forming a term of a metrological nature, the main term element (in this case, measuring) must be indicated first, then the additional one (information). This provision is reflected in the note to the above definition.
• The essence of the second approach is reflected in the definitions given in the recommendation MI 2438-97 "GSI. Measuring systems. Metrological support. Basic provisions", where IS is considered as component more complex structures - IIS, which can implement the following functions: measuring information, logical (pattern recognition, control), diagnostics, computing.
• It is necessary to note one important point, reflected in paragraph 2 of the note to the definition given in MI 2438-97. IS (as well as IIS) are considered as a type of SI. According to paragraph 1 of the note to the same definition, in complex systems it is recommended to combine the measuring channels into a separate subsystem with clearly defined boundaries. The last circumstance is related to one of the features of the IIS. The assembly of an IMS as a single, complete product from parts produced by various manufacturing plants is often carried out only at the site of operation.
• As a result of this, there may be no factory regulatory and technical documentation (technical conditions) regulating the technical, in particular, metrological requirements for the IMS as a single product. Accordingly, difficulties arise in carrying out tests for type approval purposes.
• The possibility of developing, increasing the IMS during operation or the possibility of changing its composition (structure) depending on the goals of the experiment, essentially complicates or eliminates the regulation of requirements for such IMS, in contrast to conventional measuring instruments, which are “completed” products at the time of their release by the manufacturer . To ensure appropriate regulation, subsystems are distinguished within the framework of a more complex IIS. In further presentation, the abbreviation IIS will be understood as the term “information-measuring system” as the most common and used in MI 2438-97. The name “information” indicates: - the final product obtained using the information information system.
• The main process of empirical cognition is measurement, with the help of which primary quantitative information is obtained. Therefore, the clarifying “measurement” is added to the concept of “informational”.
• One of the conditions for considering SI as a system is the necessity and expediency of changes in its structure. Changes can be made both from application to application (multifunctional system) and during application (controlled or adaptive systems).
• If the structure of the SI is unchanged and the conditions of its use remain the same during the period of operation, it is possible to determine the SI model of the “input-output” type. For example, electronic measuring instruments for temperature measurement series 3144.644 from Emerson have standardized MX and, from the consumer’s point of view, are not considered from a system perspective. Automation is also not necessarily associated with the structure of the SI, interpreted as a system. The compact device, considered as a single product, can be highly automated.
• In the development of information systems, two stages can be distinguished, the boundary between which is determined by the inclusion of computer technology in the systems. At the first stage, the structure and functions of the system are clearly coordinated and the measuring function is decisive. Information functions associated with displaying measurement results are considered auxiliary.
• At the second stage, the system becomes informational in a broad sense, i.e. allows you to implement not only measuring, but also other information functions. The result is the creation of IMS, which are designed to perform, based on measurements, control functions, tests, diagnostics, etc.
• calibration information measuring error
• Tterms and definitions
• Metrology- the science of measurements, methods and means of ensuring their unity and methods of achieving the required accuracy.
• Unity of measurements- a state of measurements, characterized by the fact that their results are expressed in legal units, the sizes of which, within established limits, are equal to the sizes of units reproduced by primary standards, and the errors of the measurement results are known and with a given probability do not go beyond the established limits.
• Ensuring uniformity of measurements- activities of metrological services. aimed at achieving and maintaining the uniformity of measurements in accordance with legislative acts, as well as the rules and regulations established by state standards and other regulatory documents to ensure the uniformity of measurements.
• State system ensuring uniformity of measurements- a set of regulatory documents at the interregional and intersectoral levels, establishing rules, norms, requirements aimed at achieving and maintaining the uniformity of measurements in the country (with the required accuracy), approved by the State Standard of the country.
• Physical quantity- one of the properties of a physical object, common in qualitative terms for many physical objects, but in quantitative terms individual for each of them.
• Unit of physical quantity- a physical quantity of a fixed size, which is conventionally assigned a numerical value equal to 1, and is used for the quantitative expression of physical quantities similar to it.
• Measurement- a set of operations for the use of a technical means that stores a unit of physical quantity, ensuring the determination of the relationship of the measured quantity with its unit and obtaining the value of this quantity.
• Measuring instrument- a technical device intended for measurements and having standardized metrological characteristics.
• Measurement error-- deviation of the measurement result from true meaning measured quantity.
• Measuring instrument error-- the difference between the reading of a measuring instrument and the true value of the measured physical quantity.
• Verification of measuring instruments- a set of operations performed to confirm the compliance of measuring instruments with metrological requirements.
• Calibration of measuring instrument- a set of operations performed in order to determine the actual values ​​of the metrological characteristics of a measuring instrument.
• Measuring system(IS): A set of measuring, connecting, computing components forming measuring channels, and auxiliary devices (components of the measuring system), functioning as a single whole, intended for:
• - obtaining information about the state of an object using measurement transformations in the general case of a set of quantities varying in time and distributed in space that characterize this state;
• - machine processing of measurement results;
• - registration and indication of measurement results and the results of their machine processing;
• - converting this data into system output signals for various purposes.
• Measuring channel of the measuring system (measuring channel IC): A structurally or functionally distinguishable part of an IC that performs a complete function from the perception of the measured quantity to the receipt of the result of its measurements, expressed by a number or a corresponding code, or to the receipt of an analog signal, one of the parameters of which is a function of the measured quantity.
• Measurement system component (IC component): Included in the IP technical device, performing one of the functions provided by the measurement process.
• 1. Verificationand calibration of IIS
• 1.1 Are commonprovisions
• Verification is carried out on IC measuring channels covered by a type approval certificate, subject to use or used in the areas of state metrological control and supervision:
• IS-1 - primarily when released from production or repair, when imported and periodically during operation. The need for initial verification of IS-1 measuring channels after installation at the facility is determined when the IS-1 type is approved;
• IS-2 - primarily during commissioning into permanent operation after installation on site or after repair (replacement) of IS-2 components that affect the error of the measuring channels, and periodically during operation.
• If, in the scope of state metrological control and supervision, only a part of the total number of IS measuring channels covered by the type approval certificate is used, and the remaining part is used outside this scope, then only the first part of the measuring channels should be subjected to verification. In this case, the remaining part of the measuring channels is subjected to calibration.
• The verification certificate or calibration certificate of such ICs indicates the channels to which they are distributed.
• During the initial verification of IS-2 installed according to a standard design, it is necessary to check the compliance of a specific instance of IS-2 with the standard design in terms of completeness and other project requirements.
• Programs are checked for compliance with certified programs and security from unauthorized access.
• IC measuring channels that are not subject to use or are not used in the areas of state metrological control and supervision are subject to calibration.
• Calibration of the IC measuring channels is carried out in accordance with and.
• According to the definition, IIS have all the characteristics of SI. Accordingly, all the basic principles underlying the SI verification procedure apply to IIS, their IC and components.
• 1.2 Mmethods for monitoring metrological characteristics
• A complete verification is called in which the MX SIs inherent in it as a single whole are determined.
• Element-by-element verification is called in which the MX values ​​of an SI are established by the MX of its constituent elements or parts. Element-by-element verification is typical for IS and IIS.
• As follows from the definition, verification is a control procedure, an integral part of which is the experimental determination of the MX of the control object. The most preferred way to control and determine the MX IR IMS and their components is the “end-to-end” method. With the “end-to-end” method, a reference signal simulating the measured value is supplied to the input of the IR IMS. At the output of the controlled IR IMS, the output signal (measurement result) is removed. The MX values ​​obtained as a result of the experiment are used for comparison with the normalized MX of the IR-controlled IIS. The necessary conditions for applying the "end-to-end" method of determining and controlling MX are:
• availability of access to the IR input. Restricted access may be due to the design or installation methods of primary measuring transducers (sensors), the presence of a “harmful environment in their locations, climatic conditions, etc.;
• the ability to specify the required set of all the values ​​of influencing quantities that are essential for verification of the IC IMS, characteristic of the operating conditions of the IMS;
• availability of standards and means of specifying measured values.
• In cases where the above conditions for using the “end-to-end” method of monitoring and determining MX of the IC IIS are not met for the IC IIS, a computational and experimental method is used. In the IC, such a part is allocated that consists of components with normalized MX, for which the “end-to-end” method is applicable. It is desirable that the accessible part of the IC include as many of its components as possible, in order to, if possible, cover communication lines, functional converters, communication devices with the object, and computing devices when monitoring MX. MX of the IC as a whole are calculated from the experimentally determined MX of the accessible part and the normalized or assigned MX (based on the results of previously conducted experimental studies) of the inaccessible part of the IC.
• The choice of experimental method for determining and monitoring MX IR IIS depends on a number of influencing factors that determine the setup and conduct of the experiment. The choice of these methods is also influenced by the presence or absence of a priori information about the metrological properties of the IR IMS and the type of IR. A priori information about the composition and significance of influencing factors can be obtained: from ND and TD on the IIS. In the absence of a priori information on the composition and significance of factors affecting the accuracy of measurements, a preliminary study of the metrological properties of the IR IMS is carried out. Such studies are usually carried out as part of research or preliminary tests carried out at the stages of development, design of an information system or its commissioning. Such studies are not carried out as part of verification work.
• The IR verification methodology for specific IMS samples is developed at the development stage, preliminary research, checked and approved at the testing stage for the purposes of type approval. Some generalized MX control methods have been developed and are used in the verification of IC IIS. However, given the complexity of the composition of the IMS, verification methods in the vast majority of cases are individual for specific samples or types of IMS. The following are some of the common control methods.
• Let's consider the case when influencing factors predominate, which lead to a natural distortion of measurement results, and the standard deviation (a measure of uncertainty assessed by type A) can be neglected. Structural scheme to perform verification of analog and digital-to-analog ICs is shown in Fig. 1.
• Fig.1. Block diagram of IR verification.
• Standard 1 sets, at the IR input, the values ​​of the measured quantity corresponding to the tested points of the measurement range. When checking digital-analog ICs, an arbitrary code setter is used as standard 1. Reference 2 measures the IR output values ​​(in
• In a particular case, when a indicating analog measuring device is installed at the IR output, its readings are read). For each tested point X of the input signal, the lower Bb and upper Bt boundaries are calculated, within which the IR output signals can be located (readings of standard 2).
• B b = F n (X) - D o
• B t = F n (X) + D 0 ,
• where F n (X) is the value of the IR output signal, calculated for the tested point X using the nominal IR conversion function;
• D o - limit (limit) of permissible deviations of the IR output signal from the nominal value.
• If necessary, a control tolerance can be introduced equal to 0.8 of the D o limit. Using standard 1, the X values ​​corresponding to the checked points of the measurement range are set sequentially, the readings of standard 2 are read and recorded. If the inequality is satisfied for all checked points X
• B b< Y(X) < B t ,
• where Y(X) is the value of the output signal of the IR with an input signal equal to X. The IR is considered to satisfy the specified requirements (suitable). If at least one of the points being checked this inequality is not satisfied, then the IC is considered not to satisfy the specified requirements (rejected).
• The block diagram for performing verification of analog-to-digital ICs is shown in Fig. 2. Let's consider a similar case when influencing factors predominate, which lead to a natural distortion of measurement results, and the standard deviation (a measure of uncertainty assessed by type A) can be neglected.
• Fig.2. Block diagram of analog-to-digital IR verification.
• The standard sets at the IR input the values ​​X of the measured quantity or its carrier, corresponding to the tested points of the measurement range. The IR output produces a code (reading) N, which can be read by an experimenter or automatic device. For each checked point N o (for analog-digital IR, the checked points are set
• indicating the value N o of the output code or indication) calculate the values ​​of Xki and control signals using the formulas:
• Chi = F no (N o) - D o
• Xk2 = F no (N o) + D o ,
• where F no (N o) is the value of the IR input signal, calculated for the point being tested using the nominal inverse IR conversion function;
• D o - the limit of permissible deviations of the input signal from the nominal value.
• If necessary, a control tolerance can be introduced equal to 0.8 of the D o limit.
• Set the value of the X value supplied to the IR input equal to Xki and record the output code (reading) Ni of the tested IR. If the inequality Ni > N o is satisfied, the tested IC is rejected. Otherwise, set the value of the value X supplied to the IR input equal to Xk2 and record the output code (indication) N2 of the tested IR. If the inequality N2 is satisfied< N o , проверяемый ИК бракуют. ИК должен удовлетворять установленным нормам для всех контролируемых точек диапазона измерений.
• IIS and IR IIS, not subject to GMKN, are subject to calibration. Despite the fact that the legislative aspect is the main one in the separation of the concepts of verification and calibration, the content of calibration work is somewhat different from the content of verification work, as follows from the definition given in RMG 29-99. Further in RMG 29-99 there is a note indicating that the calibration results make it possible to determine corrections and other MX SI. Considering the fact that the operation of an IMS often occurs in conditions of a lack of a priori information about the MX of its components and the IMS as a whole, verification work (as well as calibration work) should be carried out taking into account the need to constantly clarify the MX of the IMS, the degree of their degradation over time, and establish and MPI adjustments, which are often (as a rule in relation to IIS-3) individual for each specific IIS sample. When developing and ME verification (calibration) methods and conducting tests for the purposes of type approval, this fact must be taken into account by both the developer and the customer. The results of verifications and calibrations should be one of the most important pieces of information that should be taken into account when analyzing changes in MX IR IMS.
• 1.3 Method for determining error
• Method for determining the error of analog and digital-analog IR for the case of a negligible random error component
• If the tested point of the measurement range X is specified in units of a directly measured quantity or its carrier, then according to standard 1, set the value of the input signal equal to X, read and record the readings Y of standard 2 and calculate the value D of the absolute IR error, expressed in units of the output signal, using the formula
• where F n (X) is the value of the IR output signal, calculated for the test point X using the nominal direct IR conversion function.
• If the tested point of the measurement range Y is specified in units of the output medium or reading, then according to standard 1, such a value of the input signal X is set at which the reading of standard 2 is equal to Y.
• The absolute error value is calculated in units of the IR input signal using the formula
• A method for determining the error characteristics of analog and digital-analog IR for the case of a significant random component of the error.
• At each point being checked, at least n = 10 readings D i (where i = l, 2, ... n) of the error of the tested IR are taken.
• In the case when great accuracy of the experiment is not required, or there is reason to consider the distribution law of the random component of the error to be normal, it is possible to take the parameter p = 2 to simplify the calculations. Otherwise, it is advisable to apply the methodology of paragraph 5.1 in full.
• A method for determining the error of analog-to-digital IR for the case of a negligible random error component.
• An option that can be used for any ratio of the nominal quantization stage and the IR error limit, but is required for use with D 0< 5q; проверяемые точки диапазона измерений задают указанием значения N 0 выходного кода или показания ИК.
• By adjusting the output signal of standard 1 (the control stage should be no more than 0.25 q (0.25 of the nominal quantization stage of the tested IR), set at the IR input such a value X m of the directly measured quantity or its carrier, at which a transition from code (indication) N 0 - q to a given code N 0 of the point being checked, or an approximately equal alternation of codes N 0 - q and N 0 occurs. The value of the IR error at the output code N 0 is calculated by the formula
• Moreover, the formula is written for the case when N 0 0, X m 0, q is positive. If N 0< 0, Х m < 0, то величине q следует приписать знак минус. Методика не применима, если величины N 0 , N 0 - q и Х m имеют разные знаки.
• Option allowed for use only at D 0 5q; The points of the measurement range to be checked are specified by indicating the value X 0 of the directly measured quantity or its carrier, received at the IR input.
• The input of the channel being tested is supplied from standard 1 with the value X 0 of the measured quantity or its carrier corresponding to the point being tested in the measurement range. The value N of the output code (reading) of the IR is read and recorded. If a random alternation of adjacent codes (indications) is observed, then the code (indication) that is most different from the value X 0 is read. Calculate the IR error using the formula
• Note. It should be borne in mind that the method has a methodological error. The estimate of the IR error always turns out to be less (in absolute value) than its true value, and this decrease can reach the size of the nominal quantization stage q of the tested IR.
• Method for determining the characteristics - errors of analog-digital IR for the case of a significant random component of the error
• The method is used when the standard deviation of the random component of the error exceeds 0.25q, i.e. for any value of the measured quantity, within any quantization stage, at least two values ​​of the output code (reading) of the IR alternate randomly. The points of the measurement range to be checked are specified by indicating the value X 0 of the directly measured quantity or its carrier.
• The input of the channel under test is supplied from standard 1 with the value X 0 of the measured quantity or its carrier, corresponding to the point of the measurement range under study. Read and register n 10 values ​​N i (where i = 1, 2, ..., n) of the IR output code (reading). IR error values ​​are calculated using the formula
• When calculating the standard deviation of the random component of the error determined, the Sheppard correction should be introduced
• where is the lp-estimate of the standard deviation, calculated using the formula in clause 5.1.3 for the found value of p.
• At p = 2:
• If the radical expression turns out to be less than zero, it should be assumed that the random component of the error is negligible compared to the nominal quantization stage of the IR, i.e. S P = 0.
• 1. 4 Problems andsolutionsin areaverificationand calibrationIIS
• The problems of testing SI and IMS are closely related to the problems of their metrological reliability, which is understood as the ability of SI (IMS) to maintain set MX values ​​for a given time under certain modes and operating conditions. Considering the uniqueness of each IIS, the problem comes down to the issue of ensuring constant monitoring of the nature of changes in the MX of the IIS and its components at the place of operation of the IIS, and the use of the information obtained to adjust the MPI. One of the important ways to solve this problem is to develop and improve methods of self-calibration and self-diagnosis of IR IMS.
• Many IMS are characterized by an autonomous - in the metrological sense - mode of use, when its operational connection with higher-level means in the verification scheme cannot be realized. Offline mode The use of IMS is one of the sources of the problem of decentralization in the system for ensuring the uniformity of measurements. If for traditionally used means, binding to a standard means, ultimately, moving to the place of its location, then for an autonomous information system, a counter-movement of the standard to its location is necessary. Accordingly, it is necessary to develop and improve transportable standards necessary for verification and calibration of IR IMS. It is necessary to take into account that transported standards will often be used in conditions different from the conditions of storage and use of standards in the HMS and GSMC organizations. Questions about methods and the need to use transported standards must be resolved at the stages of development and testing of the IMS.
• With the development of IMS, general trends in the development of measuring technology appear:
• increasing accuracy, expanding the range of measured quantities and measuring tasks, expanding measurement ranges;
• ensuring consumer access to measuring instruments of the highest accuracy;
• providing measurements under conditions of exposure to “harsh” external factors (high temperature, high pressure, ionizing radiation, etc.)
• Expansion of the range of measured quantities within one IMS leads to the need to “link” the IMS to several verification schemes. To solve the issues of self-calibration, it is necessary to have built-in standards in the structure of the IIS, which leads to an increase in accuracy requirements for transported standards and practical access to the highest levels of verification schemes. It should be noted that currently there are two opposing trends in the development of techniques for perceiving input quantities. In accordance with one point of view, the maximum number of operations to generate the most suitable signal for further conversion should be performed in the primary measuring transducer (sensor). The use of integrated technologies for the manufacture of sensitive elements creates favorable opportunities for the production of various smart sensors, which are integrated systems for collecting and preprocessing measurement results. Such sensors should generate signals that do not require mandatory amplification and have low sensitivity to influencing factors. Considering the need to install such sensors on site, which increases the inaccessible part of the IR IMS, there is a need to further improve computational and experimental methods for determining MX and their control. The requirements for individual calibration of smart sensors are increasing.
• In the field of the most widespread measurements, for example, temperature using thermocouples, the main task of converting signals from sensors with minimal loss of measurement information is solved using IR. In this case, simple sensors with standard characteristics are used. An example is the testing of large turbogenerators, in which hundreds of sensors, designed for different temperature ranges, are placed at different points of the test product. In this case, it is necessary to improve testing methods for multi-channel IMS.
• Transferring the size of units of physical quantities from standards to working measuring instruments (MI) is one of the tasks of MI verification, which, when applied to measuring systems (MS), can be solved in two ways: complete and element-by-element. Both of these methods formed the basis of the draft recommendations “GSI. Procedure for verification of measuring systems.” At the same time, the feedback received as a result of distributing the draft recommendations showed that metrologists involved in the development and approval of verification methods understand and interpret some of the features of each verification method differently. The purpose of this work is to consider the contradictions that have arisen and develop a unified approach to the concepts of “transfer of the size of units of physical quantities” and “verification conditions” as applied to IS.
• In accordance with GOST R 8.596-2002, during complete verification, “the metrological characteristics of the IC measuring channels as a whole (from input to channel output) are monitored.”
• With this approach, the transfer of the size of units of physical quantities of the IC from the standards should be carried out in the same way as is customary for working SI, i.e., in compliance normal conditions and mandatory introduction control tolerances (also called metrological safety coefficients) - to ensure the required verification reliability in accordance with MI 187-86 and MI 188-86. In this case, the verified measuring instrument is considered suitable for use only if, when checking the main error, its values ​​do not exceed the permissible norm:
• where is the limit of permissible basic error, regulated for the instrument being verified; - coefficient that determines the control tolerance and depends on the requirements for the reliability of verification and the relationship between the error limits of the standard and the verified measuring instrument, .
• However, an analysis of verification methods agreed upon, including by respected metrological institutes, showed exactly the opposite - control tolerances are not assigned, verification is recommended to be carried out in working conditions, accidentally existing at the time of verification. However, when checking basic Errors as permissible standards are the values ​​calculated taking into account the measurement results of the influencing quantities that developed at the time of verification according to the formula:
• where is the influence coefficient i th influencing quantity, regulated for the IR IS being verified; - measurement result i th influencing quantity; - the boundary (minimum or maximum) value of normal operating conditions closest to the measurement result, regulated for the IR IS being verified; n- the number of influencing quantities regulated as verification conditions for the IR IS being verified.
• Of course, the application of permissible norms calculated using the formula when checking basic error is rudest violation of metrological rules and can lead to a significant decrease in the reliability of the obtained verification results due to the fact that:
• - permissible standards should not exceed the limit of permissible basic error;
• - when using verification tools under operating conditions of operation of the IR IC being verified, the accepted relationship between the error limits of the standard and the IC IC being verified may be violated.
• So, is it possible to carry out a complete verification (checking the main error of the IR IC) in conditions different from normal? If we approach the consideration of this issue formally, then it is impossible, since the transfer of the size of units of physical quantities must be carried out under normal conditions.
• At the same time, during the operation of the IS, situations may arise that it is impossible to provide normal conditions for verification of the IS, but it is necessary to check the compliance of the metrological characteristics of the IS with the established standards. With this formulation of the question, we may not be talking about verification (in its usual sense), but only about the possibility of transferring the results of checking the error of the IR IS, carried out under actual operating conditions, to normal conditions. To achieve the same reliability of the verification results, the main error must be reduced due to the expansion of the range of changes in the influencing quantities and a possible increase in the error of the verification tools (under the operating conditions prevailing at the time of verification of the IS).
• It should be remembered that with a decrease in the coefficient, the probability of recognizing as unsuitable IC IS that are actually suitable for use increases. That is why verification can only be carried out when insignificant deviation of verification conditions from normal ones (for which the limit of permissible basic error is normalized). Otherwise you will have to:
• - or reduce the coefficient to such values ​​that almost all verified IC IS will be considered unsuitable,
• - or reduce the verification reliability values, i.e., increase the likelihood of recognizing as suitable ICs that are actually unsuitable for use, which, of course, is unacceptable.
• In accordance with GOST R 8.596-2002, during element-by-element verification, the primary measuring transducers (sensors) are dismantled and verified in laboratory conditions, and the secondary part - a complex component, including communication lines, is verified at the installation site of the IC while simultaneously monitoring all influencing factors acting on individual Components.
• Consequently, the transfer of the size of units of physical quantities to primary measuring transducers (sensors) must be carried out under normal conditions in accordance with the regulatory document regulating their verification (adopted by the GCI SI when approving the type of primary measuring transducers). To do this, in the IC verification methodology in the “Review of Documentation” section, it is sufficient to provide for checking the suitability for use of primary measuring transducers (by checking verification certificates or marks and imprints of verification stamps in the operational documentation).
• As for the remaining part of the IC, in accordance with GOST R 8.596-2002, the transfer of the size of units of physical quantities to a complex component, including communication lines, must be carried out at the installation site of the IC while simultaneously monitoring all influencing factors acting on individual components. In this case, all considerations should be extended to the complete verification of the remaining part of the IC.
• In such conditions, a reasonable question arises: should IS components that are SI and are part of a complex component be verified separately, or should they be verified only as part of the IS? On the one hand, such measuring instruments of an approved type, used in the areas of state metrological control and supervision, must be verified in accordance with the regulatory documents governing their verification (adopted by the GCI SI when approving their type). Consequently, the inspector of state metrological supervision has the right to demand documents confirming their verification for such measuring instruments (including measuring and computing complexes). On the other hand, such SI are part of the complex component of the IS and are not used separately from it. Why should such measuring instruments (for example, the above-mentioned measuring and computing complexes) be checked 2 times - separately and as part of a complex component? This is not only wasteful, but also impractical.
• At the same time, there are numerous systems in which all components that are SI are verified element by element in accordance with the regulatory documents governing their verification. It is obvious that in such cases, when the size of units of physical quantities has already been transferred to all components of the IS, which are SI, verification of the IS should consist only of various checks ( appearance, operating conditions of components, operability, safety characteristics, mutual influence of channels, from unauthorized access, software, etc.), which can well be carried out in working conditions.
• It should be remembered that this approach is adopted for the majority of heat meters, the components of which (flow meters, thermal converters and heat calculators) the size of units of physical quantities is transferred element by element under normal conditions, and during verification only various checks are carried out (including in the draft recommendations “GSI. Heat meters and thermal energy measuring systems... General instructions on verification methods”). The same approach was, in particular, adopted as a basis in MI 3000-2006, in which “the conditions for verification of the IS must correspond to the conditions of its operation, standardized in the technical documentation, but not go beyond the standardized conditions for the use of verification means.”
• When carrying out various checks of the IS (during its verification), it is advisable to provide for different verification conditions: when transferring the sizes of units of physical quantities - normal conditions, for other checks - operating conditions.
• Draw the attention of the GCI SI and the department of the State Register of SI to the need to comply with normal conditions when transferring the sizes of units of physical quantities and the advisability of introducing control tolerances when reviewing and agreeing on regulatory documents governing the verification of SI, which must be accompanied by reliability calculations.
• The transfer of the sizes of units of physical quantities in conditions different from normal should be used only in justified cases with a thorough check, confirmed by calculations, of the possibility of transferring the results of checking the error of the IR IS, carried out in actual operating conditions, to normal conditions.
• To resolve contradictions with state metrological supervision bodies (and other supervisory bodies), provide in the regulatory documents regulating the verification of ICs a direct indication of the inappropriateness of element-by-element verification of SIs (with an indication of their list) that are part of a complex component and are verified as a whole within its composition.
• 2. Organization of work to ensurequalityat the enterpriseFBU"Sakhalin CSM"
• Ensuring the quality of services is a strategic direction of the Sakhalin Center for Standardization, Metrology and Certification.
• In the field of quality, IICM management sets itself the achievement of the following goals:
• improve the activities of the FMC in performing the main tasks in accordance with the Charter of the FBU "Sakhalin FMC" of the Federal Agency for technical regulation and metrology, constantly meeting the requirements of Consumers in the quality and range of services;
• carry out verification and calibration of measuring instruments at a level that meets the requirements of the state system for ensuring the uniformity of measurements;
• constantly expand activities in the field of product testing;
• ensure the competitiveness of the FMC among organizations providing similar services by achieving recognition at the national level as a competent, independent and impartial body;
• annually increase the volume of services provided to consumers that meet national quality requirements, taking into account the structure of needs for these services in the region;
• Achievement of these goals is ensured by:
• the priority of quality in all activities of the Center for Medicines, and, above all, in the field of personnel, organizational and technical issues;
• systematic training and advanced training of all FMC personnel in the field of quality;
• maintaining the verification and technological base at a technical level that meets the requirements of regulatory documents for verification and calibration of measuring instruments;
• implementing the quality policy and making decisions and actions consistent only with this policy;
• providing conditions for stimulating each team member in the quality and volume of work performed.
• Total Quality Management System Meeting Requirements international standards ISO 9000 series guarantees our Consumers stable quality of services.
• FBU "Sakhalin CSM" continuously improves the quality management system in order to increase its effectiveness through corrective and preventive actions.
• The need for corrective and preventive actions to eliminate the causes of nonconformities may be determined by:
• results of internal checks (audits) of the quality system and audits by external organizations;
• the results of internal audits conducted by the management of the FBU “Sakhalin Center for Medical Management” in its divisions;
• results of analysis of consumer complaints.
• Responsibility for the coordination, registration and control of corrective and preventive actions related to the functioning and internal checks (audits) of the quality system is assigned to the representative of the quality management, the head of the laboratory, the chief metrologist and heads of departments.
• Responsibility for organizing and implementing corrective and preventive actions in subordinate departments to eliminate and prevent inconsistencies in the performance of work and provision of services, as well as based on the results of internal checks (audits) of the quality system, rests with the heads of departments.

Conclusion

Ensuring the unity and required accuracy of measurements has been and remains main task metrology. Only carrying out a systematic analysis of production, taking measures to increase its efficiency based on improving metrological support, and introducing modern methods and measuring instruments into practice will solve this problem.

The metrological service of our enterprise successfully solves many problems in the field of ensuring measurement accuracy. An example is the continuous improvement of the reference base, taking into account the requirements of modern measuring technology, as well as the requirements technological processes measuring channels of automated process control systems.

List of used literaturess

1. Federal Law “On Ensuring the Uniformity of Measurements” No. 102-FZ. 2008

2. PR 50.2.006-94 GSI. Procedure for verification of measuring instruments.

3. RMG 29-29 GSI. Metrology. Basic terms and definitions.

4. GOST 8.207-76 Direct measurements with multiple observations. Methods for processing measurement results.

5. PR 50 2.016-94 GSI. Requirements for performing calibration work.

6. MI 2439--97 State system for ensuring the uniformity of measurements. Metrological characteristics of measuring systems. Nomenclature. The principle of regulation, definition and control

7. MI 2440--97 State system for ensuring the uniformity of measurements. Methods for experimental determination and control of error characteristics of measuring channels of measuring systems and measuring complexes

8. MI 222-80 Methodology for calculating the metrological characteristics of IC IIS based on the metrological characteristics of components

9. MI 2539--99 State system for ensuring the uniformity of measurements. Measuring channels of controllers, measuring and computing, control, software and hardware systems. Verification method

10. MI 2168--91 State system for ensuring the uniformity of measurements. IIS. Methodology for calculating the metrological characteristics of measuring channels using the metrological characteristics of linear analog components

11. RD 50-453--84 Characteristics of the error of measuring instruments in real operating conditions. Calculation methods

12. MI 1552--86 State system for ensuring the uniformity of measurements. Single direct measurements. Estimation of errors of measurement results

13. MI 2083--90 State system for ensuring the uniformity of measurements. Measurements are indirect. Determination of measurement results and estimation of their errors

14. GOST R 8.596-2002 State system for ensuring the uniformity of measurements. Metrological support of measuring systems. Basic provisions.

15. Collection of reports of the III international scientific and technical conference October 2-6, 2006 Penza UDC 621.317

Metrological support of measuring systems. / Collection of reports of the III international scientific and technical conference. Ed. A. A. Danilova. - Penza, 2006. - 218 p.

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2 hours ago, ACC said:

Perhaps for some this is a crazy topic, but the question is not about the DCS or ESD. And what is the difference if it is a public benefit organization? I repeat, Art. 1 clause 3 of the Federal Law "On ensuring the uniformity of measurements". In accordance with Art. 13 clause 1 of measuring instruments intended for use in the field of state regulation to ensure the uniformity of measurements are subject to verification.

On the basis of what document am I obliged to confirm the integrity and immutability of the calculation algorithm and blocks? I don’t know which RT-MP-2421-551-2015 “Measuring and control systems SPPA-T3000. Verification methodology" is unlikely to be very different from MI 2539-99 "GSI. Measuring channels of controllers, measuring and computing, control, software and hardware complexes. Verification methodology." which describes in detail how and which IRs to check.

And the question was the following: is it a violation if an IS consisting of individual measuring instruments (such as ProSafe-RS or SPPA-T3000 and primary converters) included in the state register did not go through the type approval procedure as a whole IS. Here the opinion was voiced that non-certification of IS as a whole violates GOST R 8.596-2002 “Metrological support of measuring systems”. IMHO: this GOST was created for measuring systems that include measuring instruments that are not on the state register. And if all the measuring instruments have a type approval certificate, then it does not prohibit certifying the IP as a whole. But it doesn't oblige. Who monitors compliance with guests? RTN? Has RTN issued orders to anyone regarding this?

But DCS is not SI. And not even IP. Clear definition- Technical systems and devices with measuring functions.

I will repeat again:

The procedure for assigning technical means to technical systems and devices with measuring functions

A) The technical device, along with its main function, performs measuring functions, having appropriate metrological characteristics, and the measuring functions are additional (auxiliary) functions, and the measurement results obtained in the process of performing the main function of the technical means are used in areas of activity that are subject to the scope of state regulation to ensure the uniformity of measurements, or for other purposes;

The main function of the DCS is process control.

MI 2539-99 is from 1999, not 2017.

2 hours ago, ACC said:

On the basis of what document am I obliged to confirm the integrity and immutability of the calculation algorithm and blocks?

FZ-102

Article 9. Requirements for measuring instruments

2. The design of measuring instruments must ensure that access to certain parts of the measuring instruments is limited ( including software) in order to prevent unauthorized settings and interventions that could lead to distortion of measurement results.