Definition of the concept of technical diagnostics. Concept of technical diagnostics

Significant costs for maintaining equipment are primarily due to the low quality of its maintenance and premature repairs. To reduce labor costs and funds for maintenance and repair, it is necessary to increase productivity and improve the quality of these works by increasing the reliability and serviceability (maintainability) of manufactured units, development and better use of the production and technical base of enterprises, mechanization and automation of technological processes, implementation diagnostic tools and elements of scientific organization of labor.

Under reliability understand the property of the machine components to perform specified functions, maintaining over time the established operational values ​​within specified limits, corresponding to the specified modes and conditions of use, maintenance, repairs, storage and transportation.

Reliability during operation depends on a number of factors: the nature and volume of work performed by the machine; natural and climatic conditions; adopted system of technical maintenance and repair of equipment; quality and availability of regulatory and technical documentation and means of maintenance, storage and transportation of machines; qualifications of service personnel.

Reliability is a complex property that includes, depending on the purpose of the object or its operating conditions, a number of simple properties:

1. Reliability - the property of an object to continuously maintain operability for some operating time or for some time.

2. Durability - the property of an object to maintain operability until a limit state occurs with an established system of maintenance and repairs.

3. Maintainability - a property of an object, which consists in its adaptability to preventing and detecting the causes of failures, maintaining and restoring operability through repairs and maintenance.

4. Storability - the property of an object to continuously maintain the required performance indicators during (and after) storage and transportation.

Depending on the object, reliability can be determined by all of the listed properties or some of them. For example, the reliability of a gear wheel and bearings is determined by their durability, and the reliability of a machine is determined by durability, reliability and maintainability

A car is a complex system consisting of thousands of parts with varying manufacturing and operational tolerances. Work is carried out under different conditions, so the service life of objects of the same type is different - depending on operating conditions, operating modes and the quality of the elements. Therefore, each unit must be sent for repairs according to its actual condition.

During an individual examination (monitoring, diagnosing, forecasting), the True technical condition of each unit is established. Here the influence of the whole variety of working conditions, operator qualifications and other factors on which the technical condition of the object depends can be taken into account.

The lack of special monitoring and diagnostic equipment makes it difficult to detect many faults. Old (mostly subjective) methods can only identify significant and obvious failures and deviations. The cost of checking major systems using these methods is approximately 70-75% higher than using modern diagnostic methods.

Technical diagnostic method - a set of technological and organizational rules for performing technical diagnostic operations.

Diagnostics (from the Greek diagnostikós - able to recognize) is a branch of knowledge that studies the technical condition of diagnostic objects (machines, mechanisms, equipment, structures and other technical objects) and the manifestation of technical conditions, developing methods for their determination, with the help of which a conclusion is given (a diagnosis is made) , as well as principles of construction and organization of use of diagnostic systems. When the objects of diagnosis are objects of a technical nature, we speak of technical diagnostics.

Diagnostics is a set of methods and tools for determining the main indicators of the technical condition of individual mechanisms and the machine as a whole without disassembling them or with partial disassembly.

The result of diagnosis is diagnosis - conclusion on the technical condition of the object, indicating, if necessary, the location, type and cause of the defect.

Reliability of diagnosis– the probability that during diagnostics the technical condition in which the diagnostic object is actually located is determined.

Technical condition- a set of properties of an object subject to change during production or operation, characterized at a certain point in time by signs and state parameters established by the technical documentation for this object.

State parameter- a physical quantity that characterizes the performance or serviceability of the diagnostic object and changes during operation.

Diagnostic operation - part of the diagnostic process, the implementation of which allows one or more diagnostic parameters of an object to be determined.

Diagnostic technology - a set of methods, parameters and diagnostic operations performed systematically and consistently in accordance with technological documentation to obtain the final diagnosis.

In Fig. Figure 1 shows the structure of technical diagnostics. It is characterized by two interpenetrating and interconnected directions: the theory of recognition and the theory of control ability. Recognition theory contains sections related to the construction of recognition algorithms, decision rules and diagnostic models. The theory of controllability includes the development of tools and methods for obtaining diagnostic information, automated control and troubleshooting. Technical diagnostics should be considered as a section of the general theory of reliability.

Diagnosis includes three main stages:

· obtaining information about the technical condition of the diagnostic object;

· processing and analysis of received information;

· making a diagnosis and making a decision.

The first stage is to determine the parameters of the object’s condition, establish qualitative characteristics of the condition and obtain data on operating time; the second - in processing and comparing the obtained values ​​of state parameters with nominal, permissible and limit values, as well as using the obtained data to predict the residual life; the third is in analyzing the forecasting results and establishing the volume and timing of maintenance and repair of machine components.

Diagnosis object- the product and its components subject to diagnostics.

The following objects are considered in technical diagnostics.

Element- the simplest component of a product in this consideration, in reliability problems can consist of many parts.

Product- a unit of product for a specific purpose, considered during the periods of design, production, testing and operation.

System- a set of jointly acting elements designed to independently perform specified functions.

The concepts of element, product and system are transformed depending on the task at hand. For example, when establishing its own reliability, a machine is considered as a system consisting of individual elements - mechanisms, parts, etc., and when studying the reliability of a production line - as an element.

Object structure - a conventional diagram of its structure, formed by the sequential division of an object into structural elements (components, assembly units, etc.).

When diagnosing, they distinguish work impacts, arriving at the facility during its operation, and test influences, which are supplied to the facility only for diagnostic purposes. Diagnostics, in which only working influences are applied to the object, is called functional, and diagnostics, in which test influences are applied to the object, - test technical diagnostics.

A set of means, performers and diagnostic objects, prepared for checking state parameters or carrying it out according to the rules established by the relevant documentation, is called technical diagnostic system.

Diagnostics allows you to: reduce machine downtime due to technical faults by preventing failures by timely adjustment, replacement or repair of individual mechanisms and assemblies; eliminate unnecessary disassembly of individual mechanisms and assemblies and reduce the wear rate of parts; correctly establish the type and scope of repairs and reduce the labor intensity of ongoing repairs by reducing disassembly, assembly and repair work; make fuller use of the resources of individual units and the machine as a whole, and consequently reduce the total number of repairs and the consumption of spare parts.

Experience in implementing diagnostics shows that the time between repairs increases by 1.5...2 times, the number of failures and malfunctions decreases by 2...2.5 times, and repair and maintenance costs are reduced by 25...30%.

In addition, the maintenance system for a fixed resource (the average system) does not provide high reliability and minimal costs. This system is gradually dying out; a new and more economical method of maintenance and repair based on actual technical condition (diagnostic system) is being increasingly introduced. This makes it possible to more fully utilize the between-repair life of machines, eliminate unreasonable disassembly of mechanisms, reduce downtime due to technical faults, and reduce the labor intensity of maintenance and repair. Condition-based operation can bring benefits equivalent to the cost of 30% of the total fleet.

In some cases, it is advisable to use combined (mixed) diagnostics - representing a set of regulated technical diagnostics and diagnostics based on technical condition.

Diagnostic and combined systems require new research methods and a different mathematical apparatus. The basis should be a theory of reliability. It is necessary to study more deeply and take into account changes in the physical patterns of failure, wear and aging of parts in mechanical systems. An important role in improving the reliability management of rolling stock belongs to the development and implementation of methods for predicting the technical condition of vehicle units.

Goals and objectives of technical diagnostics. Relationship between diagnostics and reliability

The purpose of technical diagnostics is to increase the reliability and service life of technical systems. Measures to maintain the reliability of machines are aimed at reducing the rate of change in state parameters (mainly the wear rate) of their components and preventing failures. As is known, the most important indicator of reliability is the absence of failures during the operation (operation) of a technical system.

Technical diagnostics, thanks to the early detection of defects and malfunctions, makes it possible to eliminate failures during the maintenance process, which increases the reliability and efficiency of operation.

GOST Technical diagnostics Terms and definitions

STATE STANDARD OF THE USSR UNION

USSR STATE COMMITTEE FOR PRODUCT QUALITY MANAGEMENT AND STANDARDS

Moscow

UDC 001.4:658.58:620.1:006.354 Group T

TECHNICAL DIAGNOSTICS

TERMS AND DEFINITIONS

GOST

Technical diagnostics Terms and definitions

OKSTU 0090

INFORMATION DATA

1. DEVELOPED AND INTRODUCED

USSR State Committee for Product Quality Management and Standards

Ministry of Automotive and Agricultural Engineering of the USSR

Academy of Sciences of the USSR

State Commission of the USSR Council of Ministers for Food Procurement

DEVELOPERS

; , Doctor of Technical Sciences sciences (topic leaders); , Ph.D. tech. sciences; ; , Ph.D. tech. sciences; , Doctor of Technical Sciences sciences; , Ph.D. tech. sciences; ; , Doctor of Technical Sciences sciences; , Ph.D. tech. sciences; , Ph.D. tech. sciences; , Doctor of Technical Sciences sciences;

APPROVED AND ENTERED INTO EFFECT by Resolution of the USSR State Committee for Product Quality Management and Standards dated No. 000

INSPECTION DATE – 1996, inspection frequency – 5 years

INSTEAD GOST

This standard establishes the terms and definitions of basic concepts used in science and technology in the field of technical diagnostics and monitoring of the technical condition of objects.

The terms established by this standard are mandatory for use in all types of documentation and literature that are within the scope of standardization or that use the results of this activity.

1. Standardized terms with definitions are given in table. 1.

2. For each concept, one standardized term is established.

2.1. For individual standardized terms in table. 1 provides short forms for reference purposes, which are permitted to be used in cases where there is no possibility of their different interpretation.

2.2. In cases where the essential features of a concept are contained in the literal meaning of the term, the definition is not given and, accordingly, a dash is placed in the “Definition” column.

2.3. In table 1 foreign language equivalents in English are given for reference.

3. Alphabetical indexes of terms contained in the standard in Russian and their English equivalents are given in Table. 2 and 3.

4. Explanations for a number of terms established by this standard are given in the appendix.

5. Standardized terms are in bold font, their short form is in light font.

Table 1

Alphabetical index of terms in Russian

table 2

Alphabetical index of equivalent terms in English

Table 3

APPLICATION

Information

EXPLANATIONS OF TERMS

1. To the term “Technical condition of the object”

Factors under the influence of which the technical condition of an object changes include climatic conditions, aging over time, adjustment and tuning operations during manufacturing or repair, replacement of failed elements, etc.

Changes in the technical condition of an object are judged by the values ​​of diagnostic (monitored) parameters, which make it possible to determine the technical condition of the object without disassembling it.

2. To the term “Adaptability of an object to diagnosis (testability)”

The adaptability of an object for diagnosis (testability) is ensured from the stage of its development.

The design of the object and its components must provide access to control points without disassembling components and mechanisms, with the exception of opening technological hatches, plugs, etc., which provide access to the places where sensors are interfaced with diagnostic (control) means and exclude the possibility of damage to assembly units during connection of diagnostic (monitoring) means.

The design of the connection points for diagnostic (monitoring) means should be as simple as possible (threaded holes with plugs, locking devices, covers, etc.).

3. To the term “Technical diagnostic tool (technical condition monitoring)”

Hardware diagnostic (monitoring) tools include various devices: instruments, consoles, stands, special computers, built-in monitoring equipment for computers and control machines, etc.

Software diagnostic (monitoring) tools are programs recorded, for example, on punched tape. In this case, both operating programs of the object are used, containing additional operations necessary for diagnosing (monitoring) the object, and programs specially compiled based on the requirements of diagnosing (monitoring) the object.

Work programs allow for diagnosing (monitoring) an object while it is being used for its intended purpose, and special programs require breaks in the object’s performance of its work functions.

Examples of objects diagnosed by software are general-purpose or specialized computing, control or logical machines.

4. To the term “Algorithm for technical diagnostics (technical condition monitoring)”

The diagnostic (monitoring) algorithm establishes the composition and procedure for conducting elementary checks of an object and the rules for analyzing their results. An elementary test is determined by the working or test impact arriving or applied to the object, as well as by the composition of the signs and parameters that form the object’s response to the corresponding impact. Specific values ​​of signs and parameters obtained during diagnosis (control) are the results of elementary checks or the values ​​of the object’s responses.

There are unconditional diagnostic (monitoring) algorithms, in which the order of performing elementary checks is determined in advance, and conditional diagnostic (monitoring) algorithms, in which the choice of the next elementary checks is determined by the results of the previous ones.

If the diagnosis is made after completing all the elementary checks provided by the algorithm, then the latter is called an algorithm with unconditional stopping. If the analysis of the results is done after performing each elementary check, then the algorithm is a conditional stopping algorithm.

5. To the term “Diagnostic support”

Diagnostic support for an object includes principles, methods, algorithms and technical diagnostic tools.

In order for an object to be adapted for diagnostics, it is necessary to develop diagnostic software during its design.

Diagnostic support for the designed object is obtained as a result of analysis of its diagnostic model. A diagnostic model is built based on the proposed design, conditions of use and operation of the object. As a result of the study of the diagnostic model, diagnostic signs, direct and indirect parameters and methods for their assessment are established, operating conditions are determined, and diagnostic algorithms are developed. The totality of this data is called diagnostic support.

6. To the term “Diagnostic model”

Differential equations, logical relationships, signal flow diagrams, etc. can be considered as diagnostic models.

According to the methods of representing the relationships between the state of an object, elements and parameters, diagnostic models are divided into the following types: continuous, discrete, special.

The choice of one or another type of model to represent a specific object depends on a number of factors such as operating conditions, possible design, type of component elements, etc.

The choice of diagnostic models is made taking into account: the specifics of the object; terms of use; diagnostic methods.

7. To the term “Diagnostic (controlled) parameter”

For each object, you can specify many parameters that characterize its technical condition. They are selected depending on the diagnostic (control) method used.

It is necessary to distinguish between direct and indirect diagnostic (controlled) parameters. Direct - structural parameter (for example, wear, blockage in the interface, etc.) directly characterizes the technical condition of the object. An indirect parameter (for example, oil pressure, time, CO content in exhaust gases, etc.) indirectly characterizes the technical condition.

GOST Technical diagnostics Terms and definitions

Technical diagnostics- a field of knowledge covering the theory, methods and means of determining the technical condition of an object. The purpose of technical diagnostics in the general maintenance system is to reduce costs at the operation stage by carrying out targeted repairs.

Technical diagnostics- the process of determining the technical condition of an object. It is divided into test, functional and express diagnostics.

Periodic and planned technical diagnostics allows you to:

perform incoming inspection of units and spare parts when purchasing them;

minimize sudden unscheduled stops of technical equipment;

manage equipment aging.

Comprehensive diagnostics of the technical condition of equipment makes it possible to solve the following problems:

carry out repairs based on actual condition;

increase the average time between repairs;

reduce the consumption of parts during the operation of various equipment;

reduce the volume of spare parts;

reduce the duration of repairs;

improve the quality of repairs and eliminate secondary breakdowns;

extend the life of operating equipment on a strict scientific basis;

increase the safety of operation of power equipment:

reduce consumption of fuel and energy resources.

Test technical diagnostics- this is a diagnosis in which test influences are applied to the object (for example, determining the degree of wear of the insulation of electrical machines by changing the tangent of the dielectric loss angle when voltage is applied to the motor winding from the AC bridge).

Functional technical diagnostics- this is a diagnostic in which the parameters of an object are measured and analyzed when it is functioning for its intended purpose or in a special mode, for example, determining the technical condition of rolling bearings by changes in vibration during operation of electrical machines.

Express diagnostics- this is diagnostics using a limited number of parameters in a predetermined time.

Technical diagnostic object- a product or its components subject to (subject to) diagnosis (control).

Technical condition- this is a state that is characterized at a certain point in time under certain environmental conditions by the values ​​of diagnostic parameters established by the technical documentation for the object.

Technical diagnostic tools- equipment and programs with the help of which diagnostics (monitoring) is carried out.

Built-in technical diagnostic tools- these are diagnostic tools that are an integral part of the object (for example, gas relays in transformers with a voltage of 100 kV).

External technical diagnostic devices- these are diagnostic devices made structurally separately from the object (for example, a vibration control system on oil pumps).

Technical diagnostic system- a set of means, object and performers necessary to carry out diagnostics according to the rules established by the technical documentation.

Technical diagnosis- diagnostic result.

Prediction of technical condition This is a determination of the technical condition of an object with a given probability for the upcoming time interval, during which the operational (inoperative) state of the object will remain.

Technical diagnostic algorithm- a set of instructions that determine the sequence of actions during diagnostics.

Diagnostic model- a formal description of the object necessary to solve diagnostic problems. The diagnostic model can be presented as a set of graphs, tables or standards in the diagnostic space.

There are various technical diagnostic methods:

This is done using a magnifying glass, an endoscope, and other simple devices. This method is used, as a rule, constantly, when conducting external inspections of equipment when preparing it for work or during technical inspections.

Vibroacoustic method implemented using various vibration measuring instruments. Vibration is assessed by vibration displacement, vibration velocity or vibration acceleration. Assessment of the technical condition by this method is carried out by the general level of vibration in the frequency range 10 - 1000 Hz or by frequency analysis in the range 0 - 20000 Hz.

Implemented using . Pyrometers measure temperature in a non-contact manner at each specific point, i.e. To obtain information about the temperature zero, you need to scan the object with this device. Thermal imagers make it possible to determine the temperature field in a certain part of the surface of the object being diagnosed, which increases the efficiency of identifying incipient defects.

Acoustic emission method is based on recording high-frequency signals in metals and ceramics when microcracks occur. The frequency of the acoustic signal varies in the range of 5 - 600 kHz. The signal occurs at the moment of microcrack formation. Once the crack has developed, it disappears. As a result, when using this method, various methods of loading objects during the diagnostic process are used.

The magnetic method is used to identify defects: microcracks, corrosion and breaks of steel wires in ropes, stress concentration in metal structures. The voltage concentration is detected using special devices, the operation of which is based on the principles of Barkhausson and Villari.

Partial discharge method used to detect defects in the insulation of high-voltage equipment (transformers, electrical machines). The physical basis of partial discharges is that local charges of different polarities are formed in the insulation of electrical equipment. When charges are of different polarities, a spark (discharge) occurs. The frequency of these discharges varies in the range of 5 - 600 kHz, they have different powers and durations.

There are various methods for recording partial discharges:

potential method (partial discharge probe Lemke-5);

acoustic (high-frequency sensors are used);

electromagnetic (partial discharge probe);

capacitive.

It is used to identify defects in the insulation of station synchronous generators with hydrogen cooling and defects in transformers for voltages of 3 - 330 kV. chromatographic analysis of gases. When various defects occur in transformers, various gases are released in the oil: methane, acetylene, hydrogen, etc. The proportion of these gases dissolved in the oil is extremely small, but nevertheless there are instruments (chromatographs) with the help of which these gases are detected in transformer oil and the degree of development of certain defects is determined.

To measure the dielectric loss tangent in insulation in high-voltage electrical equipment (transformers, cables, electrical machines), a special device is used -. This parameter is measured when voltage is applied from rated to 1.25 rated. If the insulation is in good technical condition, the dielectric loss tangent should not change in this voltage range.

Graphs of changes in the dielectric loss tangent: 1 - unsatisfactory; 2 - satisfactory; 3 - good technical condition of insulation

In addition, for technical diagnostics of electrical machine shafts and transformer housings, the following methods can be used: ultrasonic, ultrasonic thickness gauging, radiographic, capillary (color), eddy current, mechanical testing (hardness testing, tensile testing, bending), radiographic flaw detection, metallographic analysis.

Gruntovich N.V.

Basic concepts, terms and definitions of diagnostics.

In accordance with GOST 20911-75 "Technical diagnostics. Basic terms and definitions" - technical diagnostics is a branch of knowledge that studies the technical condition of diagnostic objects, their manifestations, develops methods for determining the technical condition, as well as principles for constructing and organizing the use of diagnostic systems.

This definition is based on the concept of technical condition - as a set of properties of an object subject to change, which at each moment in time is characterized by the signs established in the technical documentation for the object.

The following pairs of types of technical condition are distinguished: serviceability and malfunction, performance and inoperability, correct functioning and incorrect functioning.

Technical condition monitoring refers to the process of determining the type of technical condition of an object.

Technical diagnostics is the process of determining the technical condition of an object with a certain accuracy.

The result of the diagnosis is a conclusion about the technical condition of the object, indicating the location, type and cause of the identified defect.

A defect is called each individual non-compliance of an object with established requirements.

Wherein, A failure is an event consisting in the transition of an object to an inoperable state due to an uncontrolled change in the physical and chemical properties of parts of a technical object.

The condition of an object in which one or more parts have failed is called a malfunction.

Technical diagnostics studies the state of any technical objects, which are called diagnostic objects (OD). The object of technical diagnostics or simply the object of diagnostics can be any industrial product, its components or workpiece, the technical condition of which is subject to determination.

Various radio-electronic equipment, their components and auxiliary devices, instruments, machines and mechanisms will be considered as diagnostic objects.

There are continuous (analog) and discrete (digital) diagnostic objects.

For continuous objects, as a rule, functional diagnostics are used, i.e. diagnostics carried out during the operation of the diagnostic object, which receives only operational influences. On the contrary, discrete ODs are characterized by test diagnostics, in which special, so-called test influences are applied to the object. Test influences and the sequence of their execution are called test.

Phenomena occurring in the diagnostic object appear at many points in the form of regular changes or constancy of current, voltage, electromagnetic or other physical field. Such phenomena are called diagnostic parameters.

Diagnostic parameters are tied to certain points at which it is possible to measure the characteristics of action processes.

Technical diagnostics are carried out within the framework technical diagnostic systems, which is understood as a set of means and an object (and, if necessary, performers), prepared for diagnostics or carried out according to its rules established in the regulatory and technical documentation.

Standard measuring instruments are used as diagnostic tools. Diagnostic tools in relation to OD can be built-in or external. Depending on the purpose for diagnostic objects of the same type or different types, there are specialized or universal technical diagnostic tools. In addition, diagnostic tools can be hardware or software. Software tools are special diagnostic programs recorded on some machine-oriented or machine-independent media.

An important concept in technical diagnostics is "depth of diagnosis » (defect search depth) is a characteristic of defect search (diagnosis), specified by indicating those components of the OD, with the accuracy to which the location of the defect is determined.

It is customary to diagnose communication equipment and automated control systems (find a defect) with a depth of up to:

microcircuit housings (radio-electronic products - REI);

standard replacement element (TEZ);

removable block;

cabinet or packaging, etc.

Technical diagnostics is closely related to the concept of maintainability. In accordance with regulatory and technical documentation maintainability is a property of an object, which consists in its adaptability to detecting and preventing the causes of failures, damage and maintaining (restoring) an operational state through maintenance and repairs.

The main quantitative indicator of maintainability is the average time to restore the working condition of a technical object, which is defined as the mathematical expectation of the restoration time (Those) and depends mainly on two components:

TV = Td + Tu,

Where, Td- average diagnostic time;

That- time to eliminate the malfunction (i.e., restoration and adjustment operations).

Statistics show that when troubleshooting is carried out out of order, this operation takes up to 80% of the total recovery time, even when performed by qualified specialists.

The objectives of studying the discipline are to study modern methods of technical diagnostics, developed on the basis of set theory, graph theory, discrete search problems, probability theory and the accumulated experience of existing diagnostic techniques for a wide class of objects with continuous and discrete transformation of information and energy, as well as acquiring logical skills analysis of typical functional units of communication equipment when single and multiple faults occur in them.

Concept "diagnostics" translated from Greek means recognition. Diagnostics deals with recognizing the state of an object. In medicine, such an object is a person, and in technology, a technical device.

Technical diagnostics solves three interrelated problems:

Checking the functionality of the diagnostic object (in our understanding of the communication device).

As a result of solving this problem, a transition occurs either to the use of the communication device for its intended purpose, or to further analysis of the state.

Search for faulty (defective) elements in the diagnostic object. When solving the second problem, the primary cause of the failure must be clarified or defective or damaged elements must be found.

Predicting the state of the diagnostic object for some time in the future, if it is known in advance that some characteristics of the object are constantly changing, may deteriorate greatly and the equipment will not be able to perform its functions.

All three tasks of technical diagnostics are related to determining the state of communications equipment and automated control systems as diagnostic objects. Solving the first problem

starts from the moment of switching on. In many cases, it consists of sequential commissioning of various sections of equipment. At each switching step, it is mandatory to check the functionality of the switched-on section of the equipment. If the result of this test is positive, the next section is turned on and its functionality is checked. If at all steps or stages of switching on the results of the performance test are positive, then the equipment is considered serviceable or operational and can be used for its intended purpose. If, at least at one stage, the result of the performance test differs from the specified one, then it should be considered that the equipment is in one of the faulty states. In this case, you need to go to solving the second problem of technical diagnostics

- to troubleshooting by removing and checking parameters from various control points of the object.

Evaluating and comparing the results of these tests leads to a gradual reduction in the number of different assumptions about the cause of the failure and the identification of the failed part or circuit. This problem is solved relatively easily for equipment containing a small number of parts and a small number of connections between them. As the volume of the diagnostic object increases, the search difficulties increase and the development of special troubleshooting procedures is required.

If the output parameter of a part or a typical replacement element deviates from the nominal value and goes beyond the tolerance range, then this part or block is considered to have failed. They are subject to restoration or replacement.

In some situations, namely, when changes in the parameters of existing communication facilities are detected, but they occur slowly, it may be advisable to move on to a joint solution of the second and third diagnostic tasks. At the same time, a search is carried out for the reason for the change in the parameter and an assessment of the period during which the equipment will still perform its functions without restoration operations. The latter circumstance plays a certain role in the operation of communications equipment as part of an object that performs specific tasks for a given time. You need to know how long you can expect a given communication device to work before failure.

The solution to the third problem is carried out in two stages:

search and detection of parts (standard replacement elements), the parameters of which have deviated from the norm, but have not yet crossed the tolerance limits;

continuous or periodic monitoring of the action of selected elements in order to establish the rate of change in their parameters and the moments of leaving the tolerance zone.

This problem is solved in order to establish in advance the facts of deviation of parameters from the norms and the impact on the equipment (to compensate for the deviation of parameters) by adjusting or repairing parts.

Thus, technical diagnostics allows not only to localize a fault, but also to predict the state of the diagnostic object for some time in advance.

Equipment– a collective term that includes machines, units, mechanisms, assemblies, as well as apparatus, columns, installations, technological lines, electrical and thermal facilities, networks, technological and piping pipelines and other devices used in the production of products and performing certain functions other technological functions. Examples of equipment: energy, mechanical, electrical, chemical, engineering.

The term “unit” has two readings:

1. Unit is a structural unit that performs a closed cycle in the general formulation of the problem. For metallurgical enterprises, this is a set of machines, mechanisms, devices and structures connected by a single technological process. Examples: blast furnace, electric furnace, ladle furnace, rolling mill, etc.
2. Unit– an assembly unit that has the properties of complete interchangeability, independent assembly and independent performance of a certain function in products for various purposes, for example, a converter lance, an electric motor, a gearbox, a pump, etc.

Car– a set of mechanisms designed to perform useful work related to the process of production, transportation, transformation of energy or information. Examples: a machine for opening a cast iron tap hole, a casting tap, etc.

Mechanism– a system of kinematically connected units and parts designed to transform the type of movement. Examples: gearbox, crank mechanism, screw drive, etc.

Knot- a product whose components are connected to each other at the manufacturer. This is an assembly unit, assembled separately from other components of the product or the product as a whole, capable of performing a specific function in products for one purpose only together with other components. The term corresponds to an assembly as a piece of mechanical equipment, including a detachable or permanent connection of several parts. Examples: bearing, drum assembly, conveyor roller, etc.

Detail– a product made from one brand of material without the use of assembly operations. This is a product manufactured as one whole, the division of which into parts is impossible without damage. Examples: shaft, nut, bolt, blade, gear, etc.

Stages of machine existence

Stages of machine existence: design, manufacturing and operation. The ideas and properties laid down by designers and machine builders are implemented and manifested at the operation stage.

Exploitation– the totality of all phases of the existence of equipment from the moment it is registered on the balance sheet until it is written off, including periods of storage, transportation, intended use and all types of maintenance and repair.

Storage– a set of measures to protect against the destructive effects of the external environment and destaffing. Audit– a set of works to determine the degree of wear of the product to determine the required volume of repair work. Assembly– a set of works to recreate a product from its component parts. Installation– a type of assembly operations performed using lifting machines to install the product in place. Setup– bringing actual deviations of operating modes into compliance with standard ones. Disassembly– dismemberment of the product into its component parts.

Maintenance– a set of operations to maintain the functionality or serviceability of a product. May include: washing, monitoring technical condition, cleaning, lubrication, fastening threaded connections, replacing components, adjustment.

Maintenance– repairs performed to ensure or restore the functionality of a product by replacing or restoring individual parts. Major renovation– repairs carried out to restore serviceability and close to full restoration of the service life of a product with the replacement of its parts, including basic ones.

Scheduled repairs– repairs, stopping for which is carried out in accordance with the requirements of regulatory and technical documentation. Unscheduled repairs– repairs carried out without prior appointment. Regulated repairs– planned repairs performed at intervals and to the extent established by the operational documentation. Repair according to technical condition– planned repairs, the scope and timing of which are determined by the technical condition of the product.

Types of technical condition

Working condition– the state of an object in which it is capable of performing all the specified functions of the object.

Faulty condition– a state of an object in which it is unable to perform at least one of the specified functions of the object. A malfunction is often a consequence of an object failure, but can also occur without it.

Operating state– the state of an object in which it is capable of performing all required functions.

Inoperative state– a state of an object in which it is unable to perform at least one of the required functions.

Critical condition– a condition of the facility that may lead to injury to operating personnel, significant material damage, or other unacceptable consequences. A critical condition is not always the result of a critical failure. Criteria for critical condition must be established for a specific object.

Limit state– the state of an object in which its further operation is unacceptable or impractical, or restoration of its working condition is impossible or impractical. The limit state occurs when the failure flow parameter becomes unacceptable and (or) the object is considered beyond repair as a result of a malfunction.

The technical condition is determined by the presence and development of faults in the object. Types of faults:

• defect– each non-compliance of the object with the established requirements;
• damage– an event consisting in a violation of the serviceable state of an object, while maintaining the serviceable state.

The development of faults leads to failure.

Refusal– an event consisting in a violation of the operational state of an object, i.e., in the loss of the ability of the object to perform the required function. Failure is an event, as opposed to "failure", which is the state and cause of failure.

Crash– a self-correcting failure or a one-time failure that can be eliminated with minor operator intervention. This is an event in which, as a result of a temporary change in the parameters of an object, interference occurs that affects performance.

Depending on the need for maintenance and repair, the following are distinguished: technical condition categories:

• good– maintenance and repair are not required;
• satisfactory– maintenance and repairs are carried out in accordance with the plan;
• bad– extraordinary maintenance or repairs are carried out;
• emergency– immediate shutdown and repairs are required.

Technical diagnostics – an area of ​​knowledge about recognizing the state of technical systems (objects), exploring the forms of manifestation of the technical state, developing methods and means for its determination.

Technical system- a material object of artificial origin, which consists of elements united by connections and entering into certain relationships with each other and with the external environment in order to perform certain useful functions. The technical system must be controlled to obtain an effective result.

Control is the process of receiving, storing and processing information to organize targeted actions.

Technical diagnostic service– a division that provides the technical services of the enterprise with information about the technical condition, prognosis and reasons for the occurrence of this condition.

Diagnosis– operations carried out to determine the presence of a malfunction and determine the causes of its occurrence.

Diagnosis of the technical condition of the object is carried out diagnostic tools(hardware and software).

Diagnostic tools and objects interacting with each other form diagnostic system.

The result of diagnosis is diagnosis, which determines the technical condition - identifying a malfunction in an object and assigning the object to a certain category of technical condition. Diagnosis is carried out in accordance with the developed algorithm.

Algorithm for technical diagnostics (monitoring of technical condition) – a set of instructions that determine the sequence of actions when carrying out diagnostics or control. In general, an algorithm is a sequence of actions built according to certain rules to achieve a set goal.

Technical diagnostic tasks

1. Determining the state in which an object is currently located.
2. Determining the state in which an object will find itself is a forecast task necessary to determine the timing of diagnosis and repair.
3. Determining the state in which the object was located is a task of genesis, used to determine the causes of failure and the development of damage.

The main objectives of technical diagnostics as a science are:

• determination of the technical condition of the diagnostic object in conditions of limited information;
• studying methods and means of obtaining diagnostic information;
• development of algorithms for automated control and detection of defects;
• minimizing diagnosis .

Technical diagnostics studies methods for obtaining and evaluating diagnostic information, diagnostic models and decision-making algorithms. Technical diagnostics is based on two theories: recognition theory and testability theory ().

Recognition theory, using diagnostic models when examining an object, determines the decisive rules for recognizing the current state and type of malfunction. Thanks to the known characteristics of faults, it becomes possible to develop optimal recognition algorithms (sequences).

Traceability theory solves issues of a rational sequence of searching for a failed or faulty element, monitoring the condition of an object. Decisions are based on the use of diagnostic information characterizing the state of the object.

Traceability– the adaptability of an object to the measurement of diagnostic parameters by diagnostic means, the ability of the product to provide a reliable assessment of the technical condition and early detection of malfunctions and failures. Controllability is created by the design of the product and the adopted technical diagnostic system.

Diagnostic model– a formalized description of the technical diagnostic object necessary for solving diagnostic problems. Description forms: analytical, tabular, vector, graphic.

Diagnostic parameter– a parameter (attribute) of an object that quantitatively or qualitatively characterizes the technical condition of the object. Diagnostic parameters have the following gradations: nominal, maximum permissible, maximum possible, emergency.

The main task of diagnosing– obtaining information about the technical condition of the object.

Standard definition according to GOST 20911-89 “Technical diagnostics. Terms and definitions": "The technical condition is characterized at a certain point in time, under certain environmental conditions, by the values ​​of the parameters established by the technical documentation for the object."

Definition of technical condition according to GOST 19919-74: “Technical condition is a set of properties of an object subject to production or operation, characterized at a certain moment by the signs established by the technical documentation for this object.”

Diagnostics is based on solving the problem of recognizing the technical condition of an object. The state of an object, in relation to mechanical equipment, is characterized by diagnostic parameters: input, output and internal ().

Input parameters– external conditions and control influences (rotation speed, applied torque, force, power, pressure, feed, speed). Output parameters(reactions) – parameters showing the behavior of an object (vibration, noise, temperature, uniformity of rotation, etc.). Internal parameters– parameters that determine the structure of an object and characterize the processes occurring inside it (dimensions of parts, gaps, roughness, distribution of forces and stresses, mechanical characteristics of the material, etc.).

The influence of input parameters when determining the technical condition must be eliminated by bringing it to standard conditions. This circumstance must be taken into account when carrying out measurements on test benches and in industrial conditions. Measurements of diagnostic parameters must be performed at a constant load.

Diagnostic parameters can be straight– directly reflecting the internal parameters of machines (torque, frequency and uniformity of rotation, gaps, surface roughness) and indirect– reflecting the relationship between internal and output parameters (physical fields: vibration, acoustic, thermal). When solving diagnostic problems, preference is usually given to indirect parameters due to the greater availability of measurements on operating equipment without disassembling the mechanism.

The process of functioning of a mechanism is determined not only by the internal properties of the elements of the mechanism. The performance of a mechanical system is influenced equally by the applied forces and the quality of maintenance. It is these three factors: the internal properties of the elements, the applied forces, the quality of maintenance and repair that determine the concept of technical condition (