Software and technical means of automation and control. Automation and technical means of automation. Automation systems design

Automation is a branch of science and technology, covering the theory and principles of construction
control systems for technical objects and processes operating without direct human participation.
A technical object (machine, engine, aircraft, production line, automated area, workshop, etc.) that requires automatic or automated
control, is called a control object (CO) or a technical control object
(TOU).
The combination of an op-amp and an automatic control device is called a system
automatic control(ACS) or automated control system (ACS).
Below are the most commonly used terms and their definitions:
element - the simplest component of devices, instruments and other means, in which
one transformation of any quantity is carried out; (we will later give more
precise definition)
node - a part of the device consisting of several more simple elements(details);
converter - a device that converts one type of signal into another in form or type
energy;
device - a collection of a certain number of elements connected to each other
appropriately, serving to process information;
device - a general name for a wide class of devices intended for measurements,
production control, calculations, accounting, sales, etc.;
block - part of the device, which is a collection of functionally combined
elements.

Topic 2

1. Sensors

A sensor is a device that converts the input effect of any physical quantity into a signal convenient for further use.

The sensors used are very diverse and can be classified according to various criteria (see Table 1).

Depending on the type of input (measured) quantity, there are: mechanical displacement sensors (linear and angular), pneumatic, electrical, flow meters, speed, acceleration, force, temperature, pressure sensors, etc.

Based on the type of output value into which the input value is converted, non-electrical and electrical are distinguished: direct current sensors (emf or voltage), alternating current amplitude sensors (emf or voltage), alternating current frequency sensors (emf or voltage), resistance sensors (active, inductive or capacitive) etc.

Most sensors are electrical. This is due to the following advantages of electrical measurements:

It is convenient to transmit electrical quantities over a distance, and the transmission is carried out with high speed;

Electrical quantities are universal in the sense that any other quantities can be converted into electrical quantities and vice versa;

They are accurately converted into a digital code and allow you to achieve high accuracy, sensitivity and speed of measurement instruments.

Based on their operating principle, sensors can be divided into two classes: generator and parametric. A separate group consists of radioactive sensors. Radioactive sensors are sensors that use phenomena such as changes in parameters under the influence of g and b rays; ionization and luminescence of certain substances under the influence of radioactive irradiation. Generator sensors directly convert the input value into electrical signal. Parametric sensors convert the input value into a change in any electrical parameter (R, L or C) of the sensor.

Based on the principle of operation, sensors can also be divided into ohmic, rheostatic, photoelectric (optoelectronic), inductive, capacitive, etc.

There are three classes of sensors:

Analog sensors, i.e. sensors that produce an analog signal proportional to the change in the input value;

Digital sensors that generate a pulse train or binary word;

Binary (binary) sensors that produce a signal of only two levels: “on/off” (0 or 1).

Figure 1 – Classification of sensors for mining machine automation systems

Requirements for sensors:

Unambiguous dependence of the output value on the input value;

Stability of characteristics over time;

High sensitivity;

Small size and weight;

No feedback on controlled process and on the controlled parameter;

Work at different conditions operation;

Various installation options.

Parametric sensors

Parametric sensors are sensors that convert input signals into a change in some parameter. electrical circuit(R, L or C). In accordance with this, active resistance, inductive, and capacitive sensors are distinguished.

Characteristic feature of these sensors is that they are used only with an external power source.

In modern automation equipment, various parametric active resistance sensors are widely used - contact, rheostatic, potentiometric sensors.

Contact sensors. The most reliable contact sensors are magnetically controlled sealed contacts (reed switches).

Figure 1 – Schematic diagram of a reed switch sensor

The sensor's sensing element, the reed switch, is an ampoule 1, inside of which contact springs (electrodes) 2, made of ferromagnetic material, are sealed. The glass ampoule is filled with a protective gas (argon, nitrogen, etc.). The tightness of the ampoule excludes bad influence(impact) of the environment on the contacts, increasing the reliability of their operation. The contacts of the reed switch located at the controlled point in space close under the action magnetic field, which is created by a permanent magnet (electromagnet) installed on a moving object. When the reed switch contacts are open, its active resistance is equal to infinity, and when closed, it is almost zero.

Sensor output signal (U out on load R1) equal to voltage U p of the power source in the presence of a magnet (object) at the control point and zero in its absence.

Reed switches are available with both make and break contacts, as well as switching and polarized contacts. Some types of reed switches - KEM, MKS, MKA.

The advantages of reed switch sensors are high reliability and mean time between failures (about 10 7 operations). The disadvantage of reed sensors is a significant change in sensitivity with a slight displacement of the magnet in the direction perpendicular to the movement of the object.

Reed sensors are used, as a rule, in the automation of lifting, drainage, ventilation and conveyor installations.

Potentiometric sensors. Potentiometric sensors are a variable resistor (potentiometer) consisting of a flat (strip), cylindrical or ring frame on which a thin wire of constantan or nichrome with high resistivity. A slider moves along the frame - a sliding contact connected mechanically to the object (see Figure 2).

By moving the slider using the appropriate drive, you can change the resistance of the resistor from zero to maximum. Moreover, the resistance of the sensor can change both according to a linear law and according to other, often logarithmic, laws. Such sensors are used in cases where it is necessary to change the voltage or current in the load circuit.

Figure 2 - Potentiometric sensor

For a linear potentiometer (see Figure 2) length l the output voltage is determined by the expression:

,

where x is the movement of the brush; k=U p / l- transfer coefficient; U p – supply voltage.

Potentiometric sensors are used to measure various process parameters - pressure, level, etc., previously converted by a sensing element in motion.

The advantages of potentiometric sensors are their design simplicity, small size, and the ability to be powered by both direct and alternating current.

The disadvantage of potentiometric sensors is the presence of a sliding electrical contact, which reduces the reliability of operation.

Inductive sensors. The principle of operation of the inductive sensor is based on a change in the inductance L of the coil 1, placed on the ferromagnetic core 2, when moving x anchors 3 (see Figure 3).

Figure 3 - Inductive sensor

The sensor circuit is powered from an AC source.

The control element of the sensors is a variable reactance - a choke with a variable air gap.

The sensor works as follows. Under the influence of an object, the armature, approaching the core, causes an increase in flux linkage and, consequently, inductance of the coil. With decreasing gap d to a minimum value, the inductive reactance of the coil x L = wL = 2pfL increases to a maximum, reducing the load current RL, which is usually an electromagnetic relay. The latter, with their contacts, switch control, protection, monitoring circuits, etc.

Advantages inductive sensors– simplicity of the device and reliability of operation due to the absence of a mechanical connection between the core and the armature, usually attached to a moving object, the position of which is controlled. The functions of an anchor can be performed by an object itself that has ferromagnetic parts, for example a skip when controlling its position in the shaft.

The disadvantages of inductive sensors are the nonlinearity of the characteristics and the significant electromagnetic force of attraction of the armature to the core. To reduce forces and continuously measure displacements, solenoid-type sensors are used, or they are called differential.

Capacitive sensors. Capacitive sensors are structurally variable capacitors various designs and shapes, but always with two plates, between which there is a dielectric medium. Such sensors are used to convert mechanical linear or angular movements, as well as pressure, humidity or environmental level into a change in capacity. In this case, to control small linear movements, capacitors are used in which the air gap between the plates changes. To control angular movements, capacitors with a constant gap and variable working area of ​​the plates are used. For monitoring tank filling levels bulk materials or liquids with constant gaps and working areas of the plates - capacitors with the dielectric constant of the medium being controlled. The electrical capacity of such a capacitor is calculated by the formula

where: S - Total intersection area of ​​the plates; δ - distance between plates; ε is the dielectric constant of the medium between the plates; ε 0 is the dielectric constant.

Based on the shape of the plates, flat, cylindrical and other types of variable capacitors are distinguished.

Capacitive sensors only operate at frequencies above 1000Hz. Use at industrial frequency is practically impossible due to the high capacitance (Xc = = ).

Generator sensors

Generator sensors are sensors that directly convert various types of energy into electrical energy. They do not require external power sources because they themselves produce emf. Generator sensors use well-known physical phenomena: the occurrence of EMF in thermocouples when heated, in photocells with a barrier layer when illuminated, the piezoelectric effect and the phenomenon of electromagnetic induction.

Induction sensors. In induction sensors, the conversion of an input non-electrical quantity into an induced emf. used to measure movement speed, linear or angular movements. E.m.f. in such sensors it is induced in coils or windings made of insulated copper wire and placed on magnetic circuits made of electrical steel.

Small-sized microgenerators that convert the angular velocity of an object into emf, the value of which is directly proportional to the rotation speed of the output shaft of the test object, are called tachogenerators of direct and alternating currents. Circuits of tachogenerators with and without an independent excitation winding are shown in Figure 4.

Figure 4 - Schemes of tachogenerators with and without an independent excitation winding

DC tachogenerators are a commutator electric machine with an armature and an excitation winding or permanent magnet. The latter do not require an additional power source. The principle of operation of such tachogenerators is that an emf is induced in the armature, which rotates in the magnetic flux (F) of a permanent magnet or field winding. (E), the value of which is proportional to the rotation frequency (ω) of the object:

E = cФn = cФω

To maintain the linear dependence of the emf. depending on the speed of rotation of the armature, it is necessary that the load resistance of the tachogenerator always remains unchanged and is many times higher than the resistance of the armature winding. The disadvantage of DC tachogenerators is the presence of a commutator and brushes, which significantly reduces its reliability. The collector provides conversion of alternating emf. armatures in direct current.

More reliable is an alternating current tachogenerator, in which the output intrinsically safe winding is located on the stator, and the rotor is permanent magnet with a corresponding constant magnetic flux. Such a tachogenerator does not require a collector, but its variable emf. converted to direct current using bridge diode circuits. The principle of operation of a synchronous alternating current tachogenerator is that when the rotor is rotated by the control object, a variable emf is induced in its winding, the amplitude and frequency of which are directly proportional to the rotor rotation speed. Due to the fact that the magnetic flux of the rotor rotates at the same frequency as the rotor itself, such a tachogenerator is called synchronous. The disadvantage of a synchronous generator is that it has bearing units, which is not appropriate for mining conditions. The diagram for controlling the speed of a conveyor belt with a synchronous tachogenerator is shown in Figure 5. Figure 5 indicates: 1 - magnetic rotor of the tachogenerator, 2 - drive roller with tread, 3 - conveyor belt, 4 - stator winding of the tachogenerator.

Figure 5 - Scheme for synchronous conveyor belt speed control

tachogenerator

For measuring linear speed To measure the movement of the working parts of scraper conveyors, magnetic induction sensors are used, which have no moving parts at all. The moving part (armature) in this case is the steel scrapers of the conveyor, moving in the magnetic flux of a permanent magnet sensor with an intrinsically safe coil. When steel scrapers cross a magnetic flux in the coil, a variable emf is induced, directly proportional to the speed of movement and inversely proportional to the gap between the steel core of the coil and the scraper. The magnetic flux, which leads to the emf, in the coil in this case changes under the influence of steel scrapers, which, moving above the sensor, cause fluctuations in the magnetic resistance along the path of closing the magnetic flux formed by the permanent magnet. The diagram for monitoring the speed of movement of the working body of a scraper conveyor using a magnetic induction sensor is shown in Figure 6. Figure 6 indicates: 1 - scraper conveyor, 2 - steel core, 3 - steel washer, 4 - plastic washer, 5 - ring permanent magnet, 6 - sensor coil

Figure 6 - Scheme for controlling the speed of movement of the working body

scraper conveyor with magnetic induction sensor

Magnetoelastic sensors. The principle of operation of magnetoelastic sensors is based on the property of ferromagnetic materials to change the magnetic permeability m when they are deformed. This property is called magnetoelasticity, which is characterized by magnetoelastic sensitivity

Permallay (iron-nickel alloy) has the highest value S m = 200 H/m2. Some varieties of permallay, when elongated by 0.1%, increase the coefficient of magnetic permeability up to 20%. However, to obtain even such small elongations, a load of the order of 100 - 200 N/mm is required, which is very inconvenient and leads to the need to reduce the cross-section of the ferromagnetic material and requires a power source with a frequency of the order of kilohertz.

Structurally, the magnetoelastic sensor is a coil 1 with a closed magnetic circuit 2 (see Figure 7). The controlled force P, deforming the core, changes its magnetic permeability and, consequently, the inductive resistance of the coil. The load current RL, for example, a relay, is determined by the resistance of the coil.

Magnetoelastic sensors are used to monitor forces (for example, when loading skips and planting cages on fists), rock pressures, etc.

The advantages of magnetoelastic sensors are simplicity and reliability.

Disadvantages of magnetoelastic sensors - required expensive materials for magnetic cores and their special processing.

Figure 7 – Magnetoelastic sensor

Piezoelectric sensors. The piezoelectric effect is inherent in single crystals of some dielectric substances (quartz, tourmaline, Rochelle salt, etc.). The essence of the effect is that under the action of dynamic mechanical forces on the crystal, electric charges arise on its surfaces, the magnitude of which is proportional to the elastic deformation of the crystal. The dimensions and number of crystal plates are selected based on the strength and the required amount of charge. Piezoelectric sensors in most cases are used to measure dynamic processes and shock loads, vibration, etc.

Thermoelectric sensors. To measure temperatures in a wide range of 200-2500 °C, thermoelectric sensors are used - thermocouples, which ensure the conversion of thermal energy into electrical emf. The principle of operation of a thermocouple is based on the phenomenon of the thermoelectric effect, which consists in the fact that when the junction and ends of thermoelectrodes are placed in an environment with different temperatures t 1 and t 2 in a circle formed by a thermocouple and a millivoltmeter, a thermo emf appears, proportional to the difference between these temperatures

Figure 8 - Thermocouple diagram

Conductors A and B of thermocouples are made of dissimilar metals and their alloys. The phenomenon of thermoelectric effect is given by a combination of such conductors A and B, copper-constantan (up to 300 ° C), copper - kopel (up to 600 ° C), chromel - kopel (up to 800 ° C), iron - kopel (up to 800 ° C) , chromel - alumel (up to 1300 ° C), platinum - platinum-rhodium (up to 1600 ° C), etc.

Thermal emf value for various types thermocouples range from tenths to tens of millivolts. For example, for a copper-constantan thermocouple it changes from 4.3 to –6.18 mB when the junction temperature changes from + 100 to – 260 o C.

Thermistor sensors. The operating principle of thermistor sensors is based on the property of the sensing element - the thermistor - to change resistance when the temperature changes. Thermistors are made of metals (copper, nickel, atin, etc.) and semiconductors (mixtures of metal oxides - copper, manganese, etc.). A metal thermistor is made of wire, for example, copper diameter approximately 0.1 mm, wound in a spiral on a mica, porcelain or quartz frame. Such a thermistor is enclosed in a protective tube with terminal clamps, which is located at the temperature control point of the object.

Semiconductor thermistors are manufactured in the form of small rods and disks with leads.

With increasing temperature, the resistance of metal thermistors increases, while for most semiconductor ones it decreases.

The advantage of semiconductor thermistors is their high thermal sensitivity (30 times more than metal ones).

The disadvantage of semiconductor thermistors is the large spread of resistance and low stability, which makes them difficult to use for measurements. Therefore, semiconductor thermistors in automation systems of mine process plants are mainly used to control the temperature values ​​of objects and their thermal protection. In this case, they are usually connected in series with an electromagnetic relay to the power source.

To measure temperature, the thermistor RK is included in a bridge circuit, which converts the resistance measurement into a voltage at the output Uout, used in the automatic control system or measuring system.

The bridge can be balanced or unbalanced.

A balanced bridge is used with the zero measurement method. In this case, the resistance R3 changes (for example, with a special automatic device) following a change in the resistance of the thermistor Rt in such a way as to ensure equality of potential at points A and B. If the scale of the resistor R3 is graduated in degrees, then the temperature can be read based on the position of its slider. The advantage of this method is high accuracy, but the disadvantage is complexity. measuring device, which is an automatic tracking system.

An unbalanced bridge produces a signal Uout, proportional to the overheating of the object. By selecting the resistances of resistors R1, R2, R3, the equilibrium of the bridge is achieved at the initial temperature value, ensuring that the condition is met

Rt / R1= R3 / R2

If the value of the controlled temperature and, accordingly, the resistance Rt changes, the balance of the bridge will be disrupted. If you connect an mV device with a scale graduated in degrees to its output, the device’s needle will show the measured temperature.

Induction flow meter

To control the supply of a drainage pumping unit, it is possible to use induction flow meters, for example, type IR-61M. The operating principle of an induction flow meter is based on Faraday's law (the law of electromagnetic induction).

Structural diagram induction flowmeter is shown in Figure 9. When a conducting liquid flows in a pipeline between the poles of a magnet, an emf occurs in a direction perpendicular to the direction of the liquid and in the direction of the main magnetic flux. U on the electrodes, proportional to the fluid velocity v:

where B is the magnetic induction in the gap between the magnet poles; d – internal diameter of the pipeline.

Figure 9 – Design diagram of an induction flow meter

If we express the speed v in terms of the volumetric flow rate Q, i.e.

Advantages of an induction flow meter:

They have a slight inertia of readings;

There are no parts inside the working pipeline (therefore they have minimal hydraulic losses).

Disadvantages of the flow meter:

The readings depend on the properties of the liquid being measured (viscosity, density) and the nature of the flow (laminar, turbulent);

Ultrasonic flow meters

The operating principle of ultrasonic flow meters is that

the speed of propagation of ultrasound in a moving medium of gas or liquid is equal to the geometric sum of the average speed of movement of the medium v ​​and the natural speed of sound in this medium.

The design diagram of the ultrasonic flow meter is shown in Figure 10.

Figure 10 - Design diagram of an ultrasonic flow meter

The emitter I creates ultrasonic vibrations with a frequency of 20 Hz and higher, which fall on the receiver P, which registers these vibrations (it is located at a distance l). Flow rate F is equal to

where S is the cross-sectional area of ​​the fluid flow; C – speed of sound in the medium (for liquid 1000-1500 m/s);

t1 is the duration of propagation of the sound wave in the direction of flow from the emitter I1 to the receiver P1;

t 2 – duration of propagation of the sound wave against the flow from the emitter I2 to the receiver P2;

l is the distance between the emitter I and the receiver P;

k – coefficient taking into account the distribution of speeds in the flow.

Advantages of an ultrasonic flow meter:

a) high reliability and speed;

b) the ability to measure non-conductive liquids.

Disadvantage: increased requirements for contamination of the controlled water flow.

2. Data transmission devices

Information is transferred from the automation object to the control device via communication lines (channels). Depending on the physical medium through which information is transmitted, communication channels can be divided into the following types:

– cable lines – electrical (symmetrical, coaxial, “ twisted pair", etc.), fiber-optic and combined electrical cables with fiber optic cores;

– power low-voltage and high-voltage electrical networks;

– infrared channels;

– radio channels.

Information transmission over communication channels can be transmitted without information compression, i.e. One information signal (analog or discrete) is transmitted over one channel, and with information compression, many information signals are transmitted over a communication channel. Information compaction is used for remote transmission of information over a considerable distance (for example, from automation equipment located on a roadway to a shearer or from a section of a mine to the surface to a dispatcher) and can be done using various types of signal coding.

Technical systems that provide transmission of information about the state of an object and control commands over a distance via communication channels can be systems remote control and measurements or telemechanical systems. In remote control and measurement systems, each signal uses its own line - a communication channel. As many signals as there are, so many communication channels are required. Therefore, with remote control and measurement, the number of controlled objects, especially over long distances, is usually limited. In telemechanical systems, only one line, or one communication channel, is used to transmit many messages to a large number of objects. Information is transmitted in encoded form, and each object “knows” its code, so the number of controlled or managed objects is practically unlimited, only the code will be more complex. Telemechanics systems are divided into discrete and analog. Discrete telecontrol systems are called telealarm systems(TS), they provide the transmission of a finite number of object states (for example, “on”, “off”). Analog television monitoring systems are called telemetering systems(TI), they provide the transmission of continuous changes in any parameters characterizing the state of the object (for example, changes in voltage, current, speed, etc.).

The elements that make up discrete signals have various qualitative characteristics: pulse amplitude, pulse polarity and duration, frequency or phase of alternating current, code in sending a series of pulses. Telemechanical systems are discussed in more detail in.

To exchange information between microprocessor controllers of various automation system devices, including control computers, special means, methods and rules of interaction are used - interfaces. Depending on the method of data transfer, a distinction is made between parallel and serial interfaces. IN parallel interface q bits of data are transmitted over q communication lines. IN serial interface Data transmission is usually carried out over two lines: one continuously transmits clock (synchronizing) pulses from the timer, and the second carries information.

In mining machine automation systems, serial interfaces of the RS232 and RS485 standards are most often used.

The RS232 interface provides communication between two computers, a control computer and a microcontroller, or communication between two microcontrollers at speeds up to 19600 bps over a distance of up to 15m.

The RS-485 interface provides data exchange between several devices over one two-wire communication line in half-duplex mode. The RS-485 interface provides data transfer at speeds up to 10 Mbit/s. The maximum transmission range depends on the speed: at a speed of 10 Mbit/s maximum length line - 120 m, at a speed of 100 kbit/s - 1200 m. The number of devices connected to one interface line depends on the type of transceivers used in the device. One transmitter is designed to control 32 standard receivers. Receivers are available with input impedances of 1/2, 1/4, 1/8 of the standard. When using such receivers, the total number of devices can be increased accordingly: 64, 128 or 256. Data transfer between controllers is carried out according to rules called protocols. Exchange protocols in most systems operate on a master-slave principle. One device on the highway is the master and initiates the exchange by sending requests to slave devices, which differ in logical addresses. One of the popular protocols is the Modbus protocol.

2. Actuators

Execution of the decision, i.e. the implementation of the control action corresponding to the generated control signal is carried out actuators (ED). In general, an actuator is a combination of an actuator (AM) and a regulatory body (RO). The location of the actuators in the block diagram of the local ACS is shown in Figure 11.

Figure 11 - Location of actuators in the block diagram of a local automatic control system

An actuator (AM) is a device designed to convert control signals generated by the control unit (PLC) into signals convenient for influencing the final link of the ACS - the regulatory body (RO).

The actuator consists of the following basic elements:

executive motor (electric motor, piston, membrane);

clutch element (coupling, hinge);

transmission-converting element (gearbox with output lever or rod);

power amplifier (electric, pneumatic, hydraulic, combined)

In a specific MI model, a number of elements (except for the actuator motor) may be missing.

The main requirement for the IM: movement of the RO with the least possible distortion of the control laws of the generated PLC, i.e. The MI must have sufficient speed and accuracy.

Main characteristics:

a) nominal and maximum torque value

on the output shaft (rotary) or forces on the output rod;

b) the rotation time of the output shaft of the IM or the stroke of its rod;

c) the maximum value of the output shaft rotation angle or stroke

d) dead zone.

Actuators are classified according to the following criteria:

1) movement of the regulatory body (rotary and linear);

2) design (electric, hydraulic, pneumatic);

Electric – with drives electric motor and an electromagnet;

Hydraulic – with drives: piston, plunger, from a hydraulic motor;

Pneumatic – with drives: piston, plunger, membrane, diaphragm, from an air motor.

In practice, electrical MI is most widely used. Electrical MI are classified as:

electromagnetic;

electric motor

Electromagnetic MI are divided into:

IMs with drives from electromagnetic clutches are designed to transmit rotational motion (friction and sliding clutches;

IMs with a solenoid drive are 2-position devices (i.e., designed for 2-position control) that carry out translational movement of the drive elements according to the discrete principle: “on - off.”

Electric motor MI are divided into:

single-turn - the angle of rotation of the output shaft does not exceed 360 0. Example: MEO (electric single-turn mechanism). They use single-phase and three-phase (MEOK, MEOB) asynchronous motors.

multi-turn – for remote and local control pipeline fittings(valves).

In automation systems of mining machines, electric hydraulic distributors, for example the GSD and 1RP2 types, are widely used as actuators. The 1RP2 electric hydraulic distributor is designed to control the feed speed and cutting elements of the combine as part of the URAN.1M automatic load controllers and the SAUK02.2M automation system. The 1RP2 electrohydraulic distributor is a hydraulic spool valve with a pull-type electromagnetic drive.

Regulatory body (RO) is the final element of the ACS that exercises direct control influence on the OS. RO changes the flow of material, energy, the relative position of parts of apparatus, machines or mechanisms in the direction of the normal flow of the technological process.

The main characteristic of the RO is its static characteristic, i.e. the relationship between the output parameter Y (flow, pressure, voltage) and the stroke value of the regulator in percent.

RO provide:

a) two-position regulation - the RO gate quickly moves from one extreme position to another.

b) continuous - in this case it is necessary that the throughput characteristic of the RO be strictly defined (gate, tap, butterfly valve).

The definitions of “automation object” include a variety of technical objects(metallurgical furnaces, transport, various machines and other technical devices), as well as production processes that can be performed by one or a whole complex of technological units, installations or machines when they interact with the control system. At this stage of human development, automation is actively being introduced into all spheres of human life.

Continuous improvement and implementation of automation systems are absolutely interconnected processes. On the one hand, to modernize various industries it is necessary to develop and implement mechanization and automation systems into already operating mechanisms, and on the other hand, when creating a completely new technology, it is necessary to provide ways for its effective automation.

According to their hierarchy, automation technical means are classified into two classes:

• Systems for automated (automatic) regulation of ACS and control of ACS;
• Devices, elements and subsystems of automatic control systems and self-propelled guns;

The common functional part of both systems is the object of regulation (control). Control object – a controlled part of the system (a machine or a set of machines), the established operating mode of which must be supported by the control part of the system in accordance with the previously selected control task.

A control system (CS) is a dynamic closed complex that consists of controlled objects and three subsystems: logical-computational, information and executive. A general diagram is shown below:

An information subsystem is a set of technical means for receiving, presenting and transmitting information. To the means whose purpose is to obtain and transform primary information about internal and external factors The work of objects over which control is carried out includes measuring and sensitive elements, analyzers, primary information sensors and other devices. This category also includes means for presenting and transmitting information in a form convenient for the control system - receivers, encoding/decoding devices, transmitters, communication channels, and so on.

Logic-computing system – technical means whose task is to process information.

The main task of information processing tools is to develop solutions necessary to achieve control tasks formulated in the technical specifications for the manufacture of self-propelled guns. These solutions are usually implemented in the form of master or control signals. Technical means of information processing include a variety of analog and digital computing tools, including microcontrollers.

Technical means, which are used to generate control signals and directly control the object, are called executive subsystem . The technical means of executive subsystems mainly include electric drives, as well as lighting and temperature controllers, electromagnets hydraulic mechanisms and so on.

Control systems, during the operation of which, including the stages of decision-making and development of control actions, are completely absent from the participation of the operator (the operator only observes the production process) are called ACS automatic control systems .

Control systems in which computers (digital, analog or hybrid) are involved in operator decision-making are called automated systems ACS control.

The introduction of technical means into enterprises that allow automation of production processes is a basic condition for effective work. Diversity modern methods automation expands the range of their applications, while the costs of mechanization are usually justified end result in the form of increasing the volume of manufactured products, as well as improving their quality.

Organizations that follow the path of technological progress occupy leading positions in the market, provide better working conditions and minimize the need for raw materials. For this reason, it is no longer possible to imagine large enterprises without implementing mechanization projects - exceptions apply only to small craft industries, where automation of production does not justify itself due to the fundamental choice in favor of manual production. But even in such cases, it is possible to partially turn on automation at some stages of production.

Automation Basics

In a broad sense, automation involves the creation of such conditions in production that will allow certain tasks for the manufacture and release of products to be performed without human intervention. In this case, the operator’s role may be to solve the most critical tasks. Depending on the goals set, automation of technological processes and production can be complete, partial or comprehensive. The choice of a specific model is determined by the complexity of the technical modernization of the enterprise due to automatic filling.

In plants and factories where full automation is implemented, usually mechanized and electronic systems management is transferred all the functionality to control production. This approach is most rational if operating conditions do not imply changes. In partial form, automation is implemented at individual stages of production or during the mechanization of an autonomous technical component, without requiring the creation of a complex infrastructure for managing the entire process. A comprehensive level of production automation is usually implemented in certain areas - this could be a department, workshop, line, etc. In this case, the operator controls the system itself without affecting the direct work process.

Automated control systems

To begin with, it is important to note that such systems assume complete control over an enterprise, factory or plant. Their functions can extend to a specific piece of equipment, conveyor, workshop or production area. In this case, process automation systems receive and process information from the serviced object and, based on this data, have a corrective effect. For example, if the operation of a production complex does not meet the parameters of technological standards, the system will use special channels to change its operating modes according to the requirements.

Automation objects and their parameters

The main task when introducing production mechanization means is to maintain the quality parameters of the facility, which will ultimately affect the characteristics of the product. Today, experts try not to delve into the essence of the technical parameters of various objects, since theoretically the implementation of control systems is possible at any component of production. If we consider in this regard the basics of automation of technological processes, then the list of mechanization objects will include the same workshops, conveyors, all kinds of devices and installations. One can only compare the degree of complexity of implementing automation, which depends on the level and scale of the project.

Regarding the parameters with which they work automatic systems, we can distinguish input and output indicators. In the first case it is physical characteristics products, as well as the properties of the object itself. In the second, these are the direct quality indicators of the finished product.

Regulating technical means

Devices that provide regulation are used in automation systems in the form of special alarms. Depending on their purpose, they can monitor and control various process parameters. In particular, automation of technological processes and production can include alarms temperature indicators, pressure, flow characteristics, etc. Technically, the devices can be implemented as scaleless devices with electrical contact elements at the output.

The operating principle of the control alarms is also different. If we consider the most common temperature devices, we can distinguish manometric, mercury, bimetallic and thermistor models. Structural design, as a rule, is determined by the principle of operation, but operating conditions also have a significant influence on it. Depending on the direction of the enterprise’s work, automation of technological processes and production can be designed taking into account specific operating conditions. For this reason, control devices are developed with a focus on use in conditions high humidity, physical pressure or the effects of chemicals.

Programmable automation systems

The quality of management and control of production processes has noticeably increased against the background of the active supply of enterprises with computing devices and microprocessors. From the point of view of industrial needs, the capabilities of programmable hardware make it possible not only to ensure effective control of technological processes, but also to automate design, as well as conduct production tests and experiments.

Computer devices that are used on modern enterprises, solve problems of regulation and control of technological processes in real time. Such production automation tools are called computing systems and operate on the principle of aggregation. The systems include unified functional blocks and modules, from which you can create various configurations and adapt the complex to work in certain conditions.

Units and mechanisms in automation systems

The direct execution of work operations is carried out by electrical, hydraulic and pneumatic devices. According to the principle of operation, the classification involves functional and portion mechanisms. IN Food Industry Such technologies are usually implemented. Automation of production in this case involves the introduction of electrical and pneumatic mechanisms, the designs of which may include electric drives and regulatory bodies.

Electric motors in automation systems

The basis of actuators is often formed by electric motors. Depending on the type of control, they can be presented in non-contact and contact versions. Units that are controlled by relay contact devices can change the direction of movement of the working parts when manipulated by the operator, but the speed of operations remains unchanged. If automation and mechanization of technological processes using non-contact devices is assumed, then semiconductor amplifiers are used - electrical or magnetic.

Panels and control panels

To install equipment that must provide control and monitoring production process At enterprises, special consoles and panels are installed. They contain devices for automatic control and regulation, instrumentation, protective mechanisms, as well as various elements communication infrastructure. By design, such a shield can be a metal cabinet or a flat panel on which automation equipment is installed.

The console, in turn, is the center for remote control - it is a kind of control room or operator area. It is important to note that the automation of technological processes and production should also provide access to maintenance by personnel. It is this function that is largely determined by consoles and panels that allow you to make calculations, evaluate production indicators and generally monitor the work process.

Automation systems design

The main document that serves as a guide for the technological modernization of production for the purpose of automation is the diagram. It displays the structure, parameters and characteristics of devices, which will later act as means of automatic mechanization. In the standard version, the diagram displays the following data:

• level (scale) of automation at a specific enterprise;
• determining the operating parameters of the facility, which must be provided with means of control and regulation;
• control characteristics - full, remote, operator;
• possibility of blocking actuators and units;
• configuration of the location of technical equipment, including on consoles and panels.

Auxiliary automation tools

Despite the minor role, additional devices provide important control and management functions. Thanks to them, the same connection between actuators and a person is ensured. In terms of equipping with auxiliary devices, production automation may include push-button stations, control relays, various switches and command panels. There are many designs and varieties of these devices, but they are all focused on ergonomic and safe control of key units on site.

Automation tools are technical means designed to assist government officials in solving information and calculation problems. The use of automation tools increases the efficiency of management, reduces the labor costs of government officials, and increases the validity of decisions made. Automation tools include the following groups of tools (Fig. 3.4):

electronic computers (computers);

interface and exchange devices (USD);

information collection and input devices;

information display devices;

devices for documenting and recording information;

automated workstations;

software tools;

facilities software;

information support tools;

means of linguistic support.

Electronic computers classified:

a) as intended– general purpose (universal), problem-oriented, specialized;

b) in size and functionality - supercomputers, large computers, small computers, microcomputers.

Supercomputers provide solutions to complex military-technical problems and

tasks for processing large volumes of data in real time.

Large and small computers provide control of complex objects and systems. Microcomputers are designed to solve information and calculation problems in the interests of specific officials. Currently, the class of microcomputers, which are based on personal computers (PCs), has become widely developed.

In turn, personal computers are divided into stationary and portable. Stationary PCs include: desktop, portable, notepads, pocket. All components of desktop PCs are made in the form of separate blocks. Portable PCs of the “Lop Top” type are made in the form of small suitcases weighing 5 – 10 kilograms. A PC notebook of the ″Note book″ or ″Sub Note book″ type is the size of a small book and has the same characteristics as a desktop PC. Pocket PCs of the “Palm Top” type have the size of a notebook and allow you to record and edit small amounts of information. Portable PCs include electronic

secretaries and electronic notebooks.

Pairing and sharing devices are designed to match the parameters of the signals of the internal computer interface with the parameters of the signals transmitted via communication channels. Moreover, these devices perform both physical matching (shape, amplitude, signal duration) and code matching. Interface and exchange devices include: adapters (network adapters), modems, multiplexers. Adapters and modems provide coordination of computers with communication channels, and multiplexers provide coordination and switching of one computer and several communication channels.

Information collection and input devices. The collection of information for the purpose of its subsequent processing on a computer is carried out by officials of control bodies and special information sensors in weapon control systems. The following devices are used to enter information into a computer: keyboards, manipulators, scanners, graphics tablets, and speech input devices.

A keyboard is a matrix of keys combined into a single unit, and an electronic unit for converting key strokes into binary code.

Manipulators (pointing devices, cursor control devices) together with the keyboard increase the user experience. Increased usability is primarily due to the ability to quickly move the cursor across the display screen. Currently, the following types of manipulators are used in PCs: a joystick (a lever mounted on the case), a light pen (used to form images on the screen), a mouse-type manipulator, a scanner - for entering images into the PC, graphics tablets - for forming and inputting images into a PC, speech input means.

Information display devices display information without long-term fixation. These include: displays, graphic boards, video monitors. Displays and video monitors are used to display information entered from the keyboard or other input devices, as well as to provide messages to the user and the results of program execution. Graphic displays provide visual display of text information in the form of a creeping line.

Documentation and information recording devices are designed to display information on paper or other media in order to ensure long-term storage. The class of these devices includes: printing devices, external storage devices (ESD).

Printing devices or printers are designed to output alphanumeric (text) and graphic information onto paper or a similar medium. The most widely used are matrix, inkjet and laser printers.

A modern PC contains at least two storage devices: a floppy magnetic disk drive (FMD) and a hard magnetic disk drive (HDD). However, in cases of processing large volumes of information, the above drives cannot ensure their recording and storage. To record and store large amounts of information, additional storage devices are used: magnetic disk and tape drives, optical drives (ODD), DVD drives. GCD type drives provide high density records, increased reliability and durability of information storage.

Automated workstations(AWS) are workplaces of government officials, equipped with communications and automation equipment. The main means of automation as part of the automated workplace is the PC.

Mathematical tools is a set of methods, models and algorithms necessary for solving information and calculation problems.

Software Tools is a collection of programs, data and program documents necessary to ensure the functioning of the computer itself and solve information and calculation problems.

Information support tools – This is a set of information necessary to solve information and calculation problems. The information support includes the actual arrays of information, a system for classifying and encoding information, and a system for unifying documents.

Linguistic support tools – a set of means and methods for presenting information that allow it to be processed on a computer. The basis of linguistic support is programming languages.