Technological parameters, objects of automatic control systems. The concepts of sensor and transducer. Displacement transducers. Differential and bridge circuits for connecting sensors. Sensors of physical quantities - temperature, pressure, mechanical effort. Control of media levels. Classification and schemes of level gauges. Methods for controlling the flow of liquid media. Variable level and variable differential pressure flowmeters. Rotameters. Electromagnetic flowmeters. Implementation of flowmeters and scope.Ways to control the density of suspensions. Manometric, weight and radioisotope density meters. Control of viscosity and composition of suspensions. Automatic granulometers, analyzers. Moisture meters for enrichment products.
7.1 General characteristics of control systems. Sensors and transducers
Automatic control is based on continuous and accurate measurement of input and output technological parameters of the enrichment process.
It is necessary to distinguish between the main output parameters of the process (or a specific machine), characterizing ultimate goal process, for example, qualitative and quantitative indicators of processed products, and intermediate (indirect) technological parameters that determine the conditions for the process, equipment operating modes. For example, for a coal cleaning process in a jigging machine, the main output parameters may be the yield and ash content of the products produced. At the same time, these indicators are affected by a number of intermediate factors, for example, the height and looseness of the bed in the jigging machine.
In addition, there are a number of parameters characterizing the technical condition of technological equipment. For example, the temperature of bearings of technological mechanisms; parameters of centralized liquid lubrication of bearings; condition of transshipment units and elements of flow-transport systems; the presence of material on the conveyor belt; the presence of metal objects on the conveyor belt, the levels of material and pulp in the tanks; duration of work and downtime of technological mechanisms, etc.
Of particular difficulty is the automatic on-line control of technological parameters that determine the characteristics of raw materials and enrichment products, such as ash content, material composition of ore, the degree of opening of mineral grains, the granulometric and fractional composition of materials, the degree of oxidation of the grain surface, etc. These indicators are either controlled with insufficient accuracy or are not controlled at all.
A large number of physical and chemical quantities that determine the modes of processing of raw materials are controlled with sufficient accuracy. These include the density and ionic composition of the pulp, volumetric and mass flow rates of process streams, reagents, fuel, air; levels of products in machines and apparatuses, ambient temperature, pressure and vacuum in apparatuses, humidity of products, etc.
Thus, the variety of technological parameters, their importance in the management of enrichment processes require the development of reliable control systems, where the on-line measurement of physical and chemical quantities is based on a variety of principles.
It should be noted that the reliability of the parameters control systems mainly determines the performance of automatic process control systems.
Automatic control systems serve as the main source of information in production management, including automated control systems and process control systems.
Sensors and transducers
The main element of automatic control systems, which determines the reliability and performance of the entire system, is a sensor that is in direct contact with the controlled environment.
A sensor is an element of automation that converts a controlled parameter into a signal suitable for entering it into a monitoring or control system.
A typical automatic control system generally includes a primary measuring transducer (sensor), a secondary transducer, an information (signal) transmission line, and a recording device (Fig. 7.1). Often, the control system has only a sensitive element, a transducer, an information transmission line and a secondary (recording) device.
The sensor, as a rule, contains a sensitive element that perceives the value of the measured parameter, and in some cases converts it into a signal convenient for remote transmission to the recording device, and, if necessary, to the control system.
An example of a sensing element would be the membrane of a differential pressure gauge that measures the pressure difference across an object. The movement of the membrane, caused by the force from the pressure difference, is converted by an additional element (converter) into an electrical signal that is easily transmitted to the recorder.
Another example of a sensor is a thermocouple, where the functions of a sensitive element and a transducer are combined, since an electrical signal proportional to the measured temperature appears at the cold ends of the thermocouple.
More details about the sensors of specific parameters will be described below.
Converters are classified into homogeneous and heterogeneous. The former have input and output values that are identical in physical nature. For example, amplifiers, transformers, rectifiers - convert electrical quantities into electrical quantities with other parameters.
Among the heterogeneous, the largest group is made up of converters of non-electric quantities into electrical ones (thermocouples, thermistors, strain gauges, piezoelectric elements, etc.).
According to the type of output value, these converters are divided into two groups: generator ones, having an active electrical value at the output - EMF and parametric ones - with a passive output value in the form of R, L or C.
Displacement transducers. The most widely used are parametric transducers of mechanical displacement. These include R (resistor), L (inductive), and C (capacitive) transducers. These elements change the output value in proportion to the input displacement: electrical resistance R, inductance L and capacitance C (Fig. 7.2).
The inductive transducer can be made in the form of a coil with a tap from the midpoint and a plunger (core) moving inside.
The converters in question are usually connected to control systems using bridge circuits. A displacement transducer is connected to one of the arms of the bridge (Fig. 7.3 a). Then the output voltage (U out), taken from the tops bridge A-B, will change when moving the working element of the transducer and can be evaluated by the expression:
The supply voltage of the bridge (U pit) can be direct (at Z i =R i) or alternating (at Z i =1/(Cω) or Z i =Lω) current with frequency ω.
Thermistors, strain- and photoresistors can be connected to the bridge circuit with R elements, i.e. converters whose output signal is a change in active resistance R.
The widely used inductive converter is usually connected to an AC bridge circuit formed by a transformer (Fig. 7.3 b). The output voltage in this case is allocated to the resistor R, included in the diagonal of the bridge.
A special group is made up of widely used induction converters - differential transformer and ferro-dynamic (Fig. 7.4). These are generator converters.
The output signal (U out) of these converters is formed as an AC voltage, which eliminates the need for bridge circuits and additional converters.
The differential principle of generating an output signal in a transformer converter (Fig. 6.4 a) is based on the use of two secondary windings connected towards each other. Here, the output signal is the vector voltage difference that occurs in the secondary windings when the supply voltage U pit is applied, while the output voltage carries two information: the absolute value of the voltage is about the magnitude of the plunger movement, and the phase is the direction of its movement:
Ū out = Ū 1 – Ū 2 = kX in,
where k is the coefficient of proportionality;
X in - input signal (plunger movement).
The differential principle of generating the output signal doubles the sensitivity of the converter, since when the plunger moves, for example, upwards, the voltage in the upper winding (Ū 1) increases due to the increase in the transformation ratio, the voltage in the lower winding decreases by the same amount (Ū 2) .
Differential transformer converters are widely used in control and regulation systems due to their reliability and simplicity. They are placed in primary and secondary instruments for measuring pressure, flow, levels, etc.
More complex is the ferrodynamic transducers (PF) of angular displacements (Fig. 7.4 b and 7.5).
Here, in the air gap of the magnetic circuit (1), a cylindrical core (2) with a winding in the form of a frame is placed. The core is installed using cores and can be rotated through a small angle α in within ± 20 °. An alternating voltage of 12 - 60 V is applied to the excitation winding of the converter (w 1), as a result of which a magnetic flux arises that crosses the area of \u200b\u200bthe frame (5). A current is induced in its winding, the voltage of which (Ū out) with other equal conditions proportional to the angle of rotation of the frame (α in), and the phase of the voltage changes when the frame is rotated in one direction or another from the neutral position (parallel to the magnetic flux).
The static characteristics of the PF converters are shown in fig. 7.6.
Characteristic 1 has a converter without the included bias winding (W cm). If the zero value of the output signal is to be obtained not on average, but in one of the extreme positions of the frame, the bias winding should be switched on in series with the frame.
In this case, the output signal is the sum of the voltages taken from the frame and the bias winding, which corresponds to a characteristic of 2 or 2 "if you change the connection of the bias winding to antiphase.
An important property of a ferrodynamic transducer is the ability to change the steepness of the characteristic. This is achieved by changing the value of the air gap (δ) between the fixed (3) and movable (4) plungers of the magnetic core, screwing or unscrewing the latter.
The considered properties of PF converters are used in the construction of relatively complex control systems with the implementation of the simplest computational operations.
General industrial sensors of physical quantities.
The efficiency of enrichment processes largely depends on the technological modes, which in turn are determined by the values of the parameters that affect these processes. The variety of enrichment processes causes a large number of technological parameters that require their control. To control some physical quantities, it is sufficient to have a standard sensor with a secondary device (for example, a thermocouple - an automatic potentiometer), for others, additional devices and converters are required (density meters, flow meters, ash meters, etc.).
Among a large number of industrial sensors, one can single out sensors that are widely used in various industries as independent sources of information and as components of more complex sensors.
In this subsection, we consider the simplest general industrial sensors of physical quantities.
Temperature sensors. The control of thermal modes of operation of boilers, dryers, and some friction units of machines makes it possible to obtain important information necessary to control the operation of these objects.
Manometric thermometers. This device includes a sensitive element (thermal bulb) and an indicating device connected by a capillary tube and filled with a working substance. The principle of operation is based on the change in the pressure of the working substance in a closed thermometer system depending on the temperature.
Depending on the state of aggregation of the working substance, liquid (mercury, xylene, alcohols), gas (nitrogen, helium) and steam (saturated steam of a low-boiling liquid) manometric thermometers are distinguished.
The pressure of the working substance is fixed by a manometric element - a tubular spring, which unwinds with increasing pressure in a closed system.
Depending on the type of working substance of the thermometer, the temperature measurement limits range from -50 ° to +1300 ° C. The devices can be equipped with signal contacts, a recording device.
Thermistors (thermoresistors). The principle of operation is based on the property of metals or semiconductors ( thermistors) change its electrical resistance with temperature. This dependence for thermistors has the form:
where R 0 – conductor resistance at T 0 \u003d 293 0 K;
α T - temperature coefficient of resistance
Sensitive metal elements are made in the form of wire coils or spirals, mainly from two metals - copper (for low temperatures - up to 180 ° C) and platinum (from -250 ° to 1300 ° C), placed in a metal protective casing.
To register the controlled temperature, the thermistor, as a primary sensor, is connected to an automatic AC bridge (secondary device), this issue will be discussed below.
In dynamic terms, thermistors can be represented as a first-order aperiodic link with a transfer function W(p)=k/(Tp+1), if the time constant of the sensor ( T) is much less than the time constant of the object of regulation (control), it is permissible to accept this element as a proportional link.
Thermocouples. Thermoelectric thermometers (thermocouples) are usually used to measure temperatures in large ranges and above 1000 ° C.
The principle of operation of thermocouples is based on the effect of the occurrence of DC EMF at the free (cold) ends of two dissimilar soldered conductors (hot junction), provided that the temperature of the cold ends differs from the temperature of the junction. The value of the EMF is proportional to the difference between these temperatures, and the value and range of measured temperatures depends on the material of the electrodes. Electrodes with porcelain beads strung on them are placed in protective fittings.
The connection of thermocouples to the recording device is made by special thermoelectrode wires. A millivoltmeter with a certain calibration or an automatic DC bridge (potentiometer) can be used as a recording device.
When calculating control systems, thermocouples can be represented, like thermistors, as a first-order aperiodic link or proportional.
The industry produces various types of thermocouples (Table 7.1).
Table 7.1 Characteristics of thermocouples
Pressure Sensors. Pressure (vacuum) and differential pressure sensors received the widest application in the mining and processing industry, both as general industrial sensors and as components of more complex systems for monitoring such parameters as pulp density, media consumption, liquid media level, suspension viscosity, etc.
Devices for measuring excess pressure are called manometers or pressure gauges, for measuring vacuum pressure (below atmospheric, vacuum) - with vacuum gauges or draft gauges, for simultaneous measurement of excess and vacuum pressure - with pressure and vacuum gauges or thrust gauges.
The most widespread are spring-type sensors (deformation) with elastic sensitive elements in the form of a manometric spring (Fig. 7.7 a), a flexible membrane (Fig. 7.7 b) and a flexible bellows.
.
To transfer readings to a recording device, a displacement transducer can be built into the pressure gauges. The figure shows inductive-transformer transducers (2), the plungers of which are connected to the sensitive elements (1 and 2).
Devices for measuring the difference between two pressures (differential) are called differential pressure gauges or differential pressure gauges (Fig. 7.8). Here, pressure acts on the sensitive element from two sides, these devices have two inlet fittings for supplying more (+ P) and less (-P) pressure.
Differential pressure gauges can be divided into two main groups: liquid and spring. According to the type of sensitive element, among the spring ones, the most common are membrane (Fig. 7.8a), bellows (Fig. 7.8 b), among liquid - bell (Fig. 7.8 c).
The membrane block (Fig. 7.8 a) is usually filled with distilled water.
Bell differential manometers, in which the sensing element is a bell partially immersed upside down in transformer oil, are the most sensitive. They are used to measure small differential pressures between 0 and 400 Pa, e.g. to monitor vacuum in the furnaces of drying and boiler installations.
The considered differential pressure gauges are scaleless, the registration of the controlled parameter is carried out by secondary devices, which receive an electrical signal from the corresponding displacement transducers.
Sensors of mechanical forces. These sensors include sensors containing an elastic element and a displacement transducer, tensometric, piezoelectric and a number of others (Fig. 7.9).
The principle of operation of these sensors is clear from the figure. Note that a sensor with an elastic element can work with a secondary device - an AC compensator, a strain gauge sensor - with an AC bridge, a piezometric sensor - with a DC bridge. This issue will be discussed in more detail in subsequent sections.
The strain gauge is a substrate on which several turns of a thin wire (special alloy) or metal foil are glued, as shown in Fig. 7.9b. The sensor is glued to the sensing element, which perceives the load F, with the orientation of the long axis of the sensor along the line of action of the controlled force. This element can be any structure that is under the influence of the force F and operates within the limits of elastic deformation. The load cell is also subjected to the same deformation, while the sensor conductor is lengthened or shortened along the long axis of its installation. The latter leads to a change in its ohmic resistance according to the formula R=ρl/S known from electrical engineering.
We add here that the considered sensors can be used to control the performance of belt conveyors (Fig. 7.10 a), measure the mass of vehicles (cars, railway cars, Fig. 7.10 b), the mass of material in bunkers, etc.
Evaluation of conveyor performance is based on weighing a certain section of the belt loaded with material at a constant speed of its movement. The vertical movement of the weighing platform (2) mounted on elastic links, caused by the mass of material on the tape, is transmitted to the plunger of the inductive-transformer converter (ITP), which generates information to the secondary device (Uout).
For weighing railway cars, loaded vehicles, the weighing platform (4) rests on strain gauge blocks (5), which are metal supports with glued strain gauges that experience elastic deformation depending on the mass of the weighing object.
The set of single operations forms specific technological processes. In the general case, the technological process is implemented through technological operations that are performed in parallel, sequentially or in combination, when the beginning of the subsequent operation is shifted relative to the beginning of the previous one.
Process control is an organizational and technical problem, and today it is solved by creating automatic or automated process control systems.
Goal Management technological process it can be: stabilization of some physical quantity, changing it according to a given program, or, in more complex cases, optimization of some generalizing criterion, the highest productivity of the process, the lowest cost of the product, etc.
Typical process parameters subject to control and regulation include flow rate, level, pressure, temperature and a number of quality indicators.
Closed systems use the current information about the output values, determine the deviation ε( t) controlled variable Y(t) from its given value Y(o) and take actions to reduce or completely eliminate ε (t).
The simplest example of a closed system, called a deviation control system, is the system shown in Figure 1 for stabilizing the water level in a tank. The system consists of a measuring transducer (sensor) of the 2nd level, a control device 1 (regulator) and an actuator 3 that controls the position of the regulating body (valve) 5.
Rice. 1. Functional diagram of the automatic control system: 1 - regulator, 2 - level measuring transducer, 3 - actuator, 5 - regulator.
Flow control
Flow control systems are characterized by low inertia and frequent parameter pulsation.
Typically, flow control is throttling the flow of a substance using a valve or gate, changing the pressure in the pipeline by changing the speed of the pump drive or the degree of bypass (diverting part of the flow through additional channels).
The principles for the implementation of flow controllers for liquid and gaseous media are shown in Figure 2, a, for bulk materials - in Figure 2, b.
Rice. 2. Flow control schemes: a - liquid and gaseous media, b - bulk materials, c - media ratios.
In the practice of automation of technological processes, there are cases when it is required to stabilize the ratio of the costs of two or more media.
In the scheme shown in Figure 2, c, the flow to G1 is the leader, and the flow G2 = γ G is the follower, where γ is the flow ratio coefficient, which is set during the static adjustment of the regulator.
When the master stream G1 is changed, the FF controller proportionally changes the slave stream G2.
The choice of the control law depends on the required quality of parameter stabilization.
Level control
Level control systems have the same features as flow control systems. In the general case, the level behavior is described by the differential equation
D(dl/dt) = G in - G out + G arr,
where S is the area horizontal section capacity, L - level, Gin, Gout - the flow rate of the medium at the inlet and outlet, G arr - the amount of the medium, increasing or decreasing in the capacity (may be equal to 0) per unit time t.
The constancy of the level indicates the equality of the amounts of supplied and consumed liquid. This condition can be ensured by influencing the supply (Fig. 3, a) or flow (Fig. 3, b) of the liquid. In the version of the regulator shown in Figure 3, c, the results of measuring the supply and flow of liquid are used to stabilize the parameter.
The pulse on the liquid level is corrective, it eliminates the accumulation of errors due to the inevitable errors that occur when the flow and flow change. The choice of the control law also depends on the required quality of parameter stabilization. In this case, it is possible to use not only proportional, but also positional controllers.
Rice. 3. Schemes of level control systems: a - with an effect on the supply, b and c - with an effect on the flow of the medium.
Pressure regulation
The constancy of pressure, as well as the constancy of the level, indicates material balance object. In the general case, the change in pressure is described by the equation:
V(dp/dt) = G in - G out + G arr,
where V is the volume of the apparatus, p is the pressure.
The pressure control methods are similar to the level control methods.
Temperature control
Temperature is an indicator of the thermodynamic state of the system. The dynamic characteristics of the temperature control system depend on the physical and chemical parameters of the process and the design of the apparatus. A feature of such a system is a significant inertia of the object and often of the measuring transducer.
The principles of implementation of temperature controllers are similar to the principles of implementation of level controllers (Fig. 2), taking into account the management of energy consumption in the facility. The choice of the control law depends on the inertia of the object: the larger it is, the more complex the control law. The time constant of the measuring transducer can be reduced by increasing the speed of the coolant, reducing the thickness of the walls of the protective cover (sleeve), etc.
Regulation of product composition and quality parameters
When regulating the composition or quality of a product, it is possible that a parameter (for example, grain moisture) is measured discretely. In this situation, information loss and a decrease in the accuracy of the dynamic control process are inevitable.
The recommended scheme of the regulator, stabilizing some intermediate parameter Y(t), the value of which depends on the main adjustable parameter - the product quality indicator Y(ti), is shown in Figure 4.
Rice. 4. Scheme of the product quality control system: 1 - object, 2 - quality analyzer, 3 - extrapolation filter, 4 - computing device, 5 - regulator.
The computing device 4, using a mathematical model of the relationship between the parameters Y(t) and Y(ti ), continuously evaluates the quality index. The extrapolation filter 3 provides an estimated product quality parameter Y(ti ) between two measurements.
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Ministry of Education and Science of the Russian Federation
Branch of the federal state budgetary educational institution higher professional education
Samara State Technical University» in Syzran
Department of Electromechanics and Industrial Automation
course project
discipline "Design automated systems»
Regulation of technological parameters at the EOLU AVT-6 unit
Completed:
Student gr. EABZ-401 Golotin K.O.
Checked:
Art. teacher Shumilov E.A.
Syzran 2014
Introduction
1. Description of the operation of the installation
3. Calculations of regulators
Conclusion
Introduction
Oil has been known to man since ancient times. For many centuries, oil has been used as a remedy, fuel, and lighting material. With the development of technology in Russia, the oil refining industry also developed, which ensured the production of various petroleum products from oil. The oil industry faces a huge task: to provide raw materials and intermediate products for the chemical and petrochemical industries. The raw materials for the development of these industries are natural and associated gas, liquefied gas and individual hydrocarbon fractions. In addition, refineries began to produce aromatic hydrocarbons, raw materials for soot, synthetic fatty acid and alcohols, as well as many other products. The modern oil refining industry is constantly under the sign of scientific and technical developments. The main technological processes at oil refineries are: desalting and dehydration of oil at the primary stage, catalytic cracking, catalytic reforming, isomerization, hydrogenation purification of petroleum distillates, etc. - at the secondary and subsequent stages.
The widespread use of secondary oil refining processes increases the requirements for the clarity of oil separation and deeper selections. Modern technological processes of oil refining are distinguished by high productivity, high flow rates and certain values of parameters, the deviation of which is allowed only in the smallest limits.
The modern world market places high demands on the quality of oil and oil products, so it is necessary to continuously improve the quality of products. And this requires the use of modern high-precision control systems.
Oil distillation processes are carried out in so-called atmospheric tubular (AT) and vacuum tubular (VT) or atmospheric-vacuum tubular (AVT) plants.
At AT units, shallow distillation of oil is carried out to obtain fuel (gasoline, kerosene, diesel) fractions and fuel oil. VT units are designed for distillation of fuel oil. The gas oil, oil fractions and tar obtained on them are used as raw materials for the processes of their subsequent (secondary) processing to obtain fuels, lubricating oils, coke, bitumen and other petroleum products.
Modern oil refining processes are combined with the processes of dehydration and desalting, secondary distillation and stabilization of the gasoline fraction: CDU-AT, CDU-AVT, etc.
1. Description of the operation of the installation
The technological process in the atmospheric block ELOU AVT-6 proceeds as follows. The oil dehydrated and desalted at CDU is additionally heated in heat exchangers and fed for separation to the partial topping column 1. The hydrocarbon gas and light gasoline leaving the top of this column are condensed and cooled in air and water coolers and sent to the irrigation tank. Part of the condensate is returned to the top of column 1 as an acute reflux. The tops oil from the bottom of the column 1 is fed into the tubular furnace 4, where it is heated to the required temperature and sent to the atmospheric column 2. Part of the tops oil from the furnace 4 is returned to the bottom of the column 1 as a hot jet. Heavy gasoline is taken from the top of column 2, and fuel fractions 180-220 (230), 220 (230) -280 and 280-350 ° C are removed from the side through stripping columns 3. The atmospheric column, in addition to acute irrigation, has two circulating irrigations, which remove heat below the plates for selecting fractions of 180-220 and 220-280 °C. Superheated water vapor is supplied to the lower parts of the atmospheric and stripping columns to strip lightly boiling fractions. From the bottom of the atmospheric column, fuel oil is removed, which is sent to a vacuum distillation unit.
2. Technological scheme of the installation
On fig. 1 shows a schematic diagram of the atmospheric distillation unit of the CDU AVT-6 unit.
1 - topping column;
2 - atmospheric column;
3 - stripping columns;
4 - atmospheric furnace;
I - oil with ELOU;
II - light gasoline;
III- heavy gasoline;
IV - fraction 180-220;
V - fraction 220-280;
VI - fraction 280-350;
VII - fuel oil;
IX - water vapor.
3. Calculation of regulators
Table 1 Data for calculation
oil refinery elo industry
A three-loop slave control system is used to control the parameters. The block diagram of such a system is shown in Fig.2.
For temperature control system in atmospheric furnace:
R1(s) - transfer function of the motor speed controller;
W11(s) - transfer function of the thyristor converter;
W12(s) - transfer function of the electric motor;
Wos1(s) - transfer function of the speed sensor;
R2(s) - transfer function of the fuel consumption regulator;
W21(s) - pump transfer function;
Wos2(s) - transfer function of the fuel consumption sensor;
R3(s) - transfer function of the temperature controller in the atmospheric furnace;
W31(s) - transfer function of the atmospheric furnace;
Wos3(s) - transfer function of the atmospheric furnace temperature sensor.
The first loop of the speed control system will be tuned to the technical optimum (Fig. 3).
Desired transfer function of the first open loop:
On the other hand:
By substituting the value into formula (2), we can calculate the transfer function of the controller:
Let's check the correctness of the calculations using computer simulation in Simulink. (Fig. 5) shows a graph of the transient process, the parameters of which correspond to the technical optimum.
Rice. 4 Diagram of the electric drive system model
Rice. 5 Transition graph
Transfer function of the first closed loop:
The second circuit of the fuel consumption control system will be adjusted to the technical optimum (Fig. 6).
Desired transfer function of the second open loop:
On the other hand:
By substituting the value into formula (4), we can calculate the transfer function of the controller:
Let's check the correctness of the calculations using computer simulation in Simulink. (Fig. 8) shows a graph of the transient process, the parameters of which correspond to the technical optimum.
Rice. 7 Diagram of the electric drive system model
Rice. 8 Transition graph
Transfer function of the second closed loop:
We adjust the third circuit of the temperature control system to a symmetrical optimum (Fig. 9).
Desired transfer function of the third open loop:
On the other hand:
By substituting the value into formula (6), we can calculate the transfer function of the controller:
Let's check the correctness of the calculations using computer simulation in Simulink. (Fig. 11) shows a graph of the transient process, the parameters of which correspond to the technical optimum.
Rice. 10 Diagram of the electric drive system model
Rice. 11 Transition graph
Conclusion
During this term paper regulators were calculated for each loop of the slave control system, the correctness of which was checked using computer simulation in Simulink. According to the obtained graphs of the transient, the overshoot, the mismatch time, the maximum time and the time of the transient were calculated. The calculated values correspond to the standard ones, depending on the selected condition (technical or symmetrical optima). The technological process in the atmospheric unit of the CDU AVT-6, which is characterized by high productivity, high flow rates and certain values of parameters, the deviation of which is allowed only in the smallest limits, has also been studied in detail.
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For the normal stable operation of NPP power units, it is necessary to maintain a number of thermal parameters within the specified limits. These functions are implemented by systems for automatic control of thermal parameters, on the reliable, efficient and stable operation of which the operation of the power unit as a whole largely depends.
In total, there are about 150 local automatic control systems (regulators) at one NPP power unit, of which approximately 30-35 can be classified as the most important, in the event of a failure of which the power unit, as a rule, is turned off by protections (level regulators in the SG, deaerator, BRU- CH, pressure in the primary circuit, etc.), or there is a decrease in the load of the power unit (level regulators in the HPH).
Maintaining the parameters manually for a long time is difficult, time-consuming and requires certain skills from the operating personnel. The operation and operational maintenance of regulators at the power unit requires the personnel to know the basics of the theory of automatic regulation, the principles of operation, the device and hardware on which the regulators are implemented.
Automatic control systems are used in cases where it is necessary to change or maintain constant for a long time any physical quantities called controlled variables (voltage, pressure, level, temperature, speed, etc.) that characterize the operation of the machine, technological process or dynamics of a moving object.
Devices that implement these functions are called automatic regulators.
The object of regulation is a machine or installation, the specified mode of operation of which must be maintained by the regulator with the help of regulatory bodies. The combination of the regulator and the object of regulation is called the automatic control system.
The automatic control system (CAP) based on the equipment "Kaskad-2" is made on the basis of microelectronics in the instrumental version.
Primary converters of the "Sapphire-22" type with strain-sensing elements, resistance thermometers and thermocouples were used as the main sources of information.
Let's consider the functional diagram of switching on block D07 with the balance of the regulator for the current value of the parameter (Figure 2.4).
Auto-regulator self-balancing to the current value is based on a change in the reference signal. When the switch is in the “P” position (manual mode), by acting on the “B” (more) or “M” (less) buttons, the regulator reference is set.
Figure 2.4 - Structural diagram of the self-balance of the autoregulator for the current value of the parameter
When the switch is in position “A” (automatic mode), the output commands of the control unit P27 (minus 24V) are sent to the inputs “ ” or “ ”, causing changes in the output signal of the block D07. When the controller is switched on, the influence of the control pulses of the P27 block on the integrator stops (normally closed contacts of the BVR relay open) and the controller reference remains equal to the value of the technological parameter at the moment of switching on.
CPS of the VVER-1000 reactor
Tasks to be solved by the NR control and protection system:
1. Ensuring a change in the power or other parameter of the reactor in the required range at the required speed and maintaining the power or other parameter at a certain predetermined level. Therefore, special CPS bodies are needed to ensure this function. They are called automatic regulation bodies (AR).
2. Compensation for changes in NR reactivity. Special KPS bodies that perform this task are called compensation bodies.
3. Security safe work NR, which can be carried out by NR by stopping the fission chain reaction in emergency situations
CPS is intended:
For automatic control of the NR power in accordance with the power supplied by the TG to the network, or power stabilization at a given level;
To start the NR and bring it to power in manual mode;
To compensate for changes in reactivity in manual and automatic mode;
Emergency protection of nuclear weapons;
For signaling the reasons for the operation of the AZ;
For automatic shunting of some AZ signals;
For signaling about malfunctions that occur in the CPS;
For signaling the position of the OR NR on the control room and control room, as well as calling information about the position of each OR in the SVRK IVS EB.
The reactor is controlled by influencing the course of the CRE with fuel nuclei in the core.
In the CPS NR being developed, a method for introducing solid absorbers in the form of rods is provided. Along with mechanical controls, the introduction of a solution of boric acid into the coolant of the primary circuit is used. operational management power is carried out by mechanical movement executive bodies containing a solid absorber.
Requirements for the CPS:
1. To electrical parameters and modes:
CPS is designed for power supply from at least two independent power sources; when one source disappears, CPS operation is maintained;
When the power supply parameters are switched off for a long time, false operation of emergency protection (EP) does not occur and the regulatory bodies do not spontaneously move;
The KMS should ensure the exchange of information with different systems.
2. To reliability:
CPS service life not less than 10 years;
MTBF by control functions 10 5 hours;
The unavailability factor for the AZ functions, requiring the shutdown of the nuclear reactor, is not more than 10 -5 ;
Average recovery time 1 hour.
3. To the hardware:
CPS equipment provides the possibility of functional verification, as well as CPS parameters using control tools in preparation for launch, with the nuclear reactor running without stopping it, without violating the system functions and the reactor plant (RP) operability;
Communication lines are designed so that a fire in one line does not lead to the inability to perform functions.
4. To actuators:
Exclusion of spontaneous movement in the direction of increasing reactivity (in the event of a malfunction, power failure, and so on);
Working speed of movement 20 ± 2 mm per second;
The time of introduction of the working bodies into the active zone is 1.5 - 4 sec;
The time from the issuance of the AZ signal to the start of movement is 0.5 seconds;
The working stroke of the regulatory body is 3500 mm.
Composition of the CPS
PTK SGIU-M
PTK AZ-PZ
PTK ARM-ROM-UPZ
Equipment power supply.
Basic concepts and definitions ............................................... ................................................. ..... four
1. Block diagrams object of regulation .............................................................. .......................... 13
2. Sequence of choosing an automation system............................................... ............... fifteen
3. Regulation of the main technological parameters.................................................... ........... 17
3.1. Flow rate regulation, flow ratio .............................................................. ............... 17
3.2. Level control .................................................................. ................................................. ..... 19
3.3. Pressure regulation .................................................................. ................................................. .21
3.4. Temperature control .................................................................. ............................................. 22
3.5. pH regulation .................................................................. ................................................. ............ 24
3.6. Regulation of composition and quality parameters .............................................................. ................. 26
Automation of the main processes of chemical technology ............................................................... ....... 27
4. Automation of hydromechanical processes............................................... ......................... 27
4.1. Automation of processes for the movement of liquids and gases .................................................... 27
4.2. Automation of separation and purification of heterogeneous systems............................................... 31
5. Automation of thermal processes............................................... ......................................... 32
5.1. Mixing heat exchanger control .................................................................. ................... 33
5.2. Regulation of surface heat exchangers............................................................... ......... 38
5.3. Automation of tube furnaces .............................................................. ...................................... 42
6. Automation of mass transfer processes............................................... ............................... 45
6.1. Automation of the rectification process .................................................................. ......................... 46
6.2. Automation of the absorption process .................................................................. ................................. 53
6.3. Automation of the process of absorption - desorption .............................................. ............. 57
6.4. Automation of the evaporation process .................................................................. ................................... 59
6.5. Automation of the extraction process............................................................... ............................... 64
6.6. Automation of the drying process .................................................................. ......................................... 66
6.6.1. Drying process in a drum dryer .............................................. ....................... 66
6.6.2. Automation of Fluidized Bed Dryers .............................................................. ................ 69
7. Automation of reactor processes.................................................... ....................................... 71
Regulation of process reactors .................................................................. ................................... 71
Control questions on the discipline to prepare for the exam .......................................................... ..74
Literature................................................. ................................................. ............................................... 76
Basic concepts and definitions
Automation is a technical discipline that deals with the study, development and creation of automatic devices and mechanisms (i.e. works without direct human intervention).
Automation is a stage of machine production, characterized by the transfer of control functions from a person to automatic devices(technical encyclopedia).
TOU- technological object control - a set of technological equipment and implemented on it technological process.
ACS- an automated control system is a human-machine system that provides automated collection and processing of information necessary for optimal control in various areas of human activity.
The development of chemical technology and other industries where continuous technological processes predominate (petrochemical, oil refining, metallurgical, etc.) required the creation of more advanced control systems than local automatic control systems. These fundamentally new systems are called automated process control systems - APCS.
Creation of automated process control systems became possible thanks to the creation of computers of the second and third generations, increase in their computing resources and reliability.
APCS- call the ACS for the development and implementation of control actions on the TOU in accordance with the accepted control criterion - an indicator that characterizes the quality of the work of the TOU and takes certain values depending on the control actions used.
ATK- a set of jointly functioning TOU and APCS forms an automated technological complex.
APCS differs from local ACS:
Better organization of information flows;
Almost complete automation of the processes of obtaining, processing and presenting information;
Possibility of active dialogue between the operating personnel and the UVM in the management process in order to develop the most effective solutions;
A higher degree of automation of control functions, including the start and stop of production.
From control systems for automatic production such as workshops and automatic factories(highest level of automation) APCS is different to a large extent human participation in management processes.
Transition from APCS to fully automatic production restrained:
Imperfection of technological processes (presence of non-mechanized technological operations;
Low reliability of technological equipment; insufficient reliability of automation and computer technology;
Difficulties in the mathematical description of tasks solved by a person in automated process control systems, etc.) Global goal of management
TOU with the help of APCS consists in maintaining the extreme value of the control criterion when all the conditions that determine
Rice. one. Typical functional structure of process control systems.
1 – primary information processing (I); 2 – detection of deviations of technological parameters and indicators of the state of the equipment from the established values (I); 3 - calculation of non-measurable quantities and indicators (I); 4 – preparation of information and implementation of exchange procedures with related and other automated control systems (I); 5 – operational and (or) on-call display and registration of information; 6 - determination of the rational mode of the technological process (U); 7 – formation of control actions that implement the selected mode.
the set of admissible values of control actions.
In most cases, the global goal is broken down into a number of sub-goals; each of them requires solving a simpler control problem.
The APCS function is called the actions of the system aimed at achieving one of the private goals of management.
Private management goals, as well as the functions that implement them, are in a certain subordination, forming the functional structure of the APCS.
APCS functions:
1. Informational - collection, transformation and storage of information about the state of the TOU; presentation of this information to operational personnel or its transfer for further processing.
2. Primary processing of information about the current state of the TOU.
3. Detection of deviations of technological parameters and indicators of the state of the equipment from the set values.
4. Calculation of values of non-measurable quantities and indicators (indirect measurements, calculation of TEP, forecasting);
5. Operational display and registration of information.
6. Exchange of information with operational personnel.
7. 
Exchange of information with adjacent and superior automated control systems. Control functions provide
ensure the maintenance of extreme values of the control criterion in a changing production situation, they are divided into two groups:
the first is the determination of optimal control actions;
the second is the implementation of this mode by forming control actions on the TOC (stabilization, program control; program-logical control).
Secondary functions
provide the solution of intrasystem tasks.
To implement the functions of the automated process control system, it is necessary:
Software;
Informational;
Organizational;
Operational staff.
Rice. 2. Technical structure of the CTS APCS for operation in the supervisory mode.
Technical structure of the CTS APCS in direct digital control mode:
AI is a source of information; USO – communication device with the object; VK - computer complex; USOP - communication device with operational personnel; OP - operational personnel; TCA - technical means automation for the implementation of the functions of local systems; IU - executive devices.
The technical support of the automated process control system is a complex of technical means (CTS),
Means of obtaining information about the current state of the TOU;
UVK (controlled computing complex);
Technical means for implementing the functions of local automation systems;
Executive devices that directly implement control actions on the TOU.
The TS complex of many automated process control systems includes mechanical means of automation from the electrical branch of the GSP.
A specific component of the CTS is the CTS, which includes the actual computer complex (CC), communication devices for the CC with the object (USO) and with operational personnel.
The first and still widespread type of technical structures of automated process control systems is centralized. In systems with a centralized structure, all the information necessary to control the ATK goes to a single center - the operator's station, where almost all the technical means of automated process control systems are installed, with the exception of information sources and executive devices. This technical structure is the simplest and has a number of advantages.
Its disadvantages are:
The need for an excessive number of APCS elements to ensure high reliability;
High cable costs.
Such systems are expedient for relatively small power and compact ATCs.
In connection with the introduction of microprocessor technology, the distributed technical structure of automated process control systems is becoming more widespread, i.e. divided into a number of autonomous subsystems - local technological control stations, geographically distributed over technological control areas. Each local subsystem is of the same type
a complete centralized structure, the core of which is a control micro-computer.
Local subsystems via
|
their microcomputers are combined into single system data network.
The number of terminals required for ATC control for operational personnel is connected to the network.
The APCS software connects all elements of a distributed technical structure into a single whole, which has a number of advantages:
The possibility of obtaining high reliability indicators by splitting the automated process control system into a family of relatively small and less complex autonomous subsystems and additional redundancy of each of these subsystems through the network;
Application of more reliable means of microelectronic computer technology;
Great flexibility in the composition and modernization of hardware and software, etc.
Most of the APCS functions are implemented in software, so the most important component of the APCS is its software (SW), i.e. a set of programs that ensure the implementation of APCS functions.
APCS software is divided into:
Special.
The general software is delivered complete with computer equipment. Special software is developed when creating a specific process control system and includes
programs that implement its information and control functions.
The software is created on the basis of software (MS). MO - a set of mathematical methods, models and algorithms for solving problems and processing information using computer technology.
To implement the information and control functions of APCS, a special MO is created, which includes:
Algorithm for collecting, processing and presenting information;
Control algorithms with mathematical models of the corresponding control objects;
Algorithms for local automation.
All interactions both within the APCS and with external environment represent various forms of information exchange, arrays of data and documents are needed that ensure the performance of all its functions during the operation of the APCS.
The rules for the exchange of information and the information itself circulating in the APCS form Information Support APCS.
Organizational support APCS is a set of descriptions of the functional, technical and organizational structures systems, instructions and regulations for operating personnel, ensuring the specified functioning of the automated process control system.
The operational personnel of the automated process control system consists of technologists-operators who manage the TOU, operational personnel ensuring the functioning of the automated process control system (computer operators, programmers, maintenance personnel for the CTS equipment).
The operational personnel of the automated process control system can work in the control loop or outside it. When working in the control loop, the OP implements all control functions or part of them,
If the operational personnel works outside the control loop, he will set the operating mode for the automated process control system and monitor its observance. In this case, depending on the composition of the CTS, the APCS can operate in two modes:
Combined (supervisory);
In the direct digital control mode, in which the UVC directly affects the actuators, changing the control actions on the TOU.
The creation of an automated process control system includes five stages:
1. terms of reference (TOR);
2. technical project (TP);
3. working draft (WP);
4. introduction of automated process control systems;
5. analysis of its functioning.
At the TK stage, the main stage is pre-project research work(R&D), usually carried out by a research organization jointly with a customer enterprise. The main task of pre-project R&D is the study of the technological process as a control object. At the same time, the goal and criteria for the quality of the functioning of the TOU, technical and economic indicators of the prototype object, their relationship with technological indicators are determined; TOU structure, i.e. input actions (including controlled and uncontrolled disturbing actions, and control actions), output coordinates and connections between them; the structure of mathematical models of statics and dynamics, the values of parameters and their stability (the degree of stationarity of the TOU); statistical characteristics of disturbing influences.
The most time-consuming task at the stage of pre-project R&D is the construction of mathematical models of TOU, which are subsequently used in the synthesis of process control systems. When synthesizing local ASRs, linearized dynamics models are usually used in the form of linear differential equations of the 1st - 2nd order with delay, which are obtained by processing experimental or calculated transient functions through different channels of influence. To solve the problems of optimal control of static modes, finite relations are used, obtained from the equations of the material and energy balance of the TOU, or the regression equation. In the problems of optimal control of dynamic modes, nonlinear differential equations are used, obtained from the equations of material and energy balance, written in differential form.
When performing pre-project research, methods of analysis of automatic control systems are used, studied in the discipline "Theory of automatic control", and methods for constructing mathematical models, which are presented in the course "Computer modeling of objects and control systems".
The results obtained at the stage of pre-project R&D are used at the stage preliminary development of process control systems, during which the following works are performed:
Selection of the criterion and mathematical formulation of the TOU optimal control problem, its decomposition (if necessary) and the choice of methods for solving global and local optimal control problems, on the basis of which the optimal control algorithm is subsequently built;
Development of functional and algorithmic structure of automated process control systems;
Determining the amount of information about the state of the TOU and VC resources (speed, storage capacity) necessary to implement all the functions of the APCS;
preselection KTS, primarily UVK;
Preliminary calculation of technical economic efficiency APCS. The central place among the works of this stage is occupied by the mathematical formulation of the problem.
chi optimal control of TOU.
The remaining tasks of this stage (except for the calculation of technical and economic efficiency) are related to the system engineering synthesis of automated process control systems, in which the analogy method is widely used. The accumulated experience in the development of automated process control systems for TOU of varying degrees of complexity allows us to transfer the development of a number of functions and algorithms from the category of scientific work to the category of technical work performed by design. These include many information functions (primary processing of initial information, calculation of TEP, integration and averaging, etc.), as well as typical functions of local automation systems implemented in the process control system programmatically (signaling, emergency blocking, regulation with using model laws under the NCU, etc.).
The final stage of the conceptual design of the automated process control system is preliminary calculation of technical and economic efficiency the system being developed. It is performed by specialists in economics, however, the initial data for them should be prepared by specialists in automation, so let's consider some key points.
The main indicator of the economic efficiency of APCS is the annual economic effect from its implementation, which is calculated by the formula
E= (FROM 2 - S 2) - (C 1 - S 1) - En(K 2 - K 1) ,
where C1 and C2- annual sales volumes of products in wholesale prices before and after the introduction of automated process control systems, thousand rubles; S1 and S2- the cost of production before and after the implementation of the system, thousand rubles; K1 and K2- capital expenditures for ATC before and after the commissioning of the automated process control system, thousand rubles; En is the normative sectoral coefficient of efficiency of capital investments in automation equipment and computer equipment, rub/ruble.
The main sources of economic efficiency of automation systems for chemical and technological processes are usually an increase in the volume of sales of products and (or) a decrease in its cost. Improvement of these economic indicators most often achieved by reducing the consumption of raw materials, materials and energy per unit of output due to more accurate maintenance of the optimal technological regime, increasing
product quality (grade and, accordingly, prices), increase in equipment productivity by reducing the loss of working time due to unscheduled process shutdowns caused by control errors, etc. At the stage of pre-project research, production reserves should be identified that can be used thanks to the use of an automation system.
For example, if when using a local automation system, the technological unit is idle on average 20% of the planned working time, of which 1/4 is caused by errors of the operating personnel due to untimely detection of pre-emergency situations, then the use of an automated process control system that implements the functions of forecasting and analysis of production situations, can eliminate these losses. Then the volume of output in physical terms will increase by 5%, which will lead to an increase in the volume of sales and a decrease in the cost of production.
The accumulated experience in the automation of chemical production has shown that the reserves of economic efficiency that can be used due to the automation of technological processes usually range from 0.5 to 6%. At the same time, the better the technology is developed, the smaller the reserves, as a rule.
However, not all identified (potential) reserves of economic efficiency can be used after the introduction of automated process control systems. The actual efficiency turns out to be less than the potential one due to the non-ideal nature of the APCS, which manifests itself, in particular, in the incomplete adequacy of the TOU mathematical model, according to which the optimal mode is calculated, in the measurement errors of the output coordinates of the object, which also affect the accuracy of determining the optimal mode, in failures of elements of hardware and software, due to which the quality of performance of individual functions and process control systems as a whole decreases, etc. The real effect usually ranges from 25 to 75% of the potential, and, as a rule, the greater the potential effect, the less it is implemented. The main indicator of the technical and economic efficiency of APCS is the payback period of the system, which is determined by the formula
= K 2 - K 1 .
(C 2 - S 2) - (C 1 - S 1)
It should be no more than the standard, which for the chemical industry is 3
The final stage of the first stage of creating an automated process control system is the development of terms of reference for the design of the system, which should include a complete list of functions, a feasibility study for the development of an automated process control system, a list and scope of R&D and a schedule for creating the system.
When developing non-standard APCS, the first stage accounts for approximately 25% of the total labor intensity, including 15% for pre-project R&D. When replicating automated process control systems, the first stage can be excluded or significantly reduced.
The next stage in the creation of a non-standard process control system is the development technical project, during which the main technical solutions are made that implement the required
technical specifications. Work at this stage is carried out by research and design organizations.
The main content of R&D is the development and deepening of pre-project R&D, in particular, the refinement of mathematical models and formulations of optimal control problems, checking, using computer simulation, the performance and efficiency of algorithms selected for the implementation of the most important information and control functions of APCS. The functional and algorithmic structures of the system are being specified, information links between functions and algorithms are being worked out, and the organizational structure of the APCS is being developed.
A very important and time-consuming stage at the TP stage is the development of special software for the system. According to available estimates, the labor intensity of creating special software was close to the total volume of pre-project R&D and amounted to 15% of the total labor costs for the creation of process control systems.
At the TP stage, the composition of the CTS is finally selected and calculations are performed to assess the reliability of implementation essential functions APCS and the system as a whole. The total labor costs for design are approximately 30% of the costs for the creation of process control systems.
At the stage of implementation of automated process control systems, installation and commissioning works are carried out, the sequence and content of which are studied in the corresponding course. Labor costs at this stage are about 30% of the total system costs.
When developing prototypes of automated process control systems to be further replicated at the same type of TOU, it is important to analyze the functioning of the system, during which the effectiveness of the decisions taken during its creation is checked and the actual technical and economic efficiency of the automated process control system is determined.
Any chemical production is a sequence of three main operations
1. preparation of raw materials;
2. actual chemical transformation;
3. selection of target products.
This sequence of operations is included in a single complex chemical-technological system (CTS).
A modern chemical enterprise, plant or combine, as a large-scale system, consists of a large number of interconnected subsystems, between which there are subordination relations in the form hierarchical structures with three main steps.
Each subsystem of a chemical enterprise is a combination of a chemical-technological system and an automatic control system, they act as a single whole to obtain a given product or intermediate.
Structural diagrams of the regulated object
⎧
xv(u)⎨
xv(z)
One of the stages of designing control systems for technological
⎫ processes - the choice of structure
⎪meters of regulators. And the structure of the sys-
Rice. 1.1. Structural diagram of the object of regulation.
process as an object of regulation.
topics, and the parameters of the regulators are determined by the properties of the technological
Any technological process as an object of regulation (Fig. 1.1) is characterized by the following main groups of variables:
1. Variables characterizing the state of the process (their totality will be denoted by the vector y). These variables in the process of regulation must be maintained at a given level or changed according to a given law. The accuracy of stabilization of state variables can be different, depending on the requirements dictated by the technology and the capabilities of the control system. As a rule, the variables included in the vector y, are measured directly, but sometimes they can be calculated using the plant model from other directly measured variables. Vector y often called the vector of controlled variables.
2. Variables, by changing which the control system can influence the object for the purpose of control. The set of these variables is denoted by the vector xp(or u) regulatory actions. Typically, changes in costs serve as regulatory influences. material flows or energy flows.
3. Variables whose changes are not related to the impact of the regulatory system. These changes reflect the influence of external conditions on the regulated object, changes in the characteristics of the object itself, etc. They are called disturbing influences and are denoted by the vector xv or z. The vector of disturbing influences, in turn, can be divided into two components - the first can be measured, and the second cannot. The ability to measure the disturbing effect allows you to introduce an additional signal into the control system, which improves the capabilities of the control system.
For example, for a continuous isothermal chemical reactor, the controlled variables are the temperature of the reaction mixture, the composition of the flow at the outlet of the apparatus; regulating influences can be a change in the steam flow rate in the reactor jacket, a change in the catalyst flow rate and the flow rate of the reaction mixture; disturbing influences are changes in the composition of the raw material, the pressure of the heating steam, and if the pressure
If the heating steam is not difficult to measure, then the composition of the raw material in many cases can be measured with low accuracy or insufficiently quickly.
The analysis of the technological process as an object of automatic control involves the assessment of its static and dynamic properties for each of the channels from any possible control action to any possible controlled parameter, as well as the assessment of similar characteristics through the channels of communication of controlled variables with the components of the disturbance vector. In the course of such an analysis, it is necessary to choose the structure of the regulatory system, i.e., to decide which regulatory action should be used to control one or another state parameter. As a result, in many cases (by no means always) it is possible to isolate the control loops for each of the regulated values, i.e., to obtain a set of single-loop control systems.
An important element of the synthesis of the ACP of the technological process is the calculation of a single-loop control system. In this case, it is required to choose a structure and find the numerical values of the controller parameters. As a rule, the following typical structures of control devices are used (typical control laws): proportional (P) controller (R(p) = -S1); integral (I) controller (R(p) = -S0/p); proportional-integral (PI) control law (R(p) = -S1 - S0/p) and, finally, proportional-integral-derivative (PID) law (R(p) = -S1 - S0/p - S2 p ). When calculating the system, they check the possibility of using the simplest regulation law, each time assessing the quality of regulation, and if it does not meet the requirements, they switch to more complex laws or use the so-called circuit quality improvement methods.
In the theory of automatic control, various methods have been developed for calculating the ASR for given quality criteria, as well as methods for assessing the quality of transient processes for given parameters of the object and the controller. At the same time, along with accurate methods that require a lot of time and manual labor, approximate methods have been developed that allow relatively quickly assessing the operating parameters of the controller or the quality of transient processes (the Ziegler–Nichols method for calculating controller settings; approximate formulas for estimating integral quadratic criterion, etc.).