Technical design of the fuel equipment repair area. Methods for setting up and adjusting radio-electronic equipment

These instructions have been developed to organize safe work on setting up, repairing, adjusting and testing radio equipment

1. GENERAL OCCUPATIONAL SAFETY REQUIREMENTS

1.1. Persons over 18 years of age who have no contraindications for health reasons, who have completed an introductory briefing on labor protection, briefing on labor safety in the workplace, and trained safe methods and methods of performing work, having passed the test of knowledge of safe work performance by the certification commission, having a qualification group for electrical safety of at least III (when working with electrical equipment with voltages up to 1000 V)
1.2. The frequency of knowledge testing is at least once a year.
1.3. The frequency of repeated medical examination is once a year.
1.4. Employees are required to undergo quarterly repeated instruction on labor protection, by profession and type of work performed.
1.5. Workers are provided with overalls, safety footwear and other personal protective equipment in accordance with current standards: cotton robe, safety glasses.
1.6. Employees are required to comply with internal labor regulations and fire safety measures.
1.7. Drinking alcoholic beverages and being under the influence of alcohol or drugs is prohibited on the territory of the enterprise.
1.8. Smoking is permitted only in specially designated and equipped areas.
1.9. When performing setup, repair, adjustment and testing of radio equipment, exposure to the following dangerous and harmful factors is possible:
- tools, workpieces, materials, devices, sharp edges, burrs;
— reduced illumination in the workplace;
— increased surface temperature of equipment, tools, and materials;
- electric shock;
- poisoning;
1.10. Workers must comply with regulations for lifting and moving loads manually. The one-time rate of mass of cargo lifted and moved manually up to two times per hour when alternating with other work is:
— for men – no more than 30 kg;
— for women – no more than 10 kg;
1.11. Work on setting up, adjusting and testing radio equipment must be carried out in separate specially designated rooms, equipped with general ventilation, by a team of at least 2 people, under supervision, with an entry in the order log.
1.12. When working, use proper tools, equipment and devices. All measuring instruments must be certified and labeled accordingly; instruments with dielectric insulating handles must be tested and appropriately marked as to their suitability for use.
1.13. Workers should only perform the work assigned by the work manager.
1.14. It is not allowed to delegate your work to other employees and allow them to enter the workplace unauthorized persons.
1.15. In the event of an accident, immediately provide first aid to the victim and, if necessary, arrange for his delivery to a medical facility or call an ambulance by calling 103, maintain the situation as it was at the time of the incident until the investigation of the accident begins, if this does not threaten the life and health of others workers and does not create an emergency situation, inform the manager.
1.16. Violation of the requirements of this instruction and other instructions on labor protection entails the application of disciplinary measures. For violations that result in accidents to people or other serious consequences, violators may be subject to administrative, financial or criminal liability.

2. OCCUPATIONAL SAFETY REQUIREMENTS BEFORE STARTING WORK

2.1. Put on overalls, fasten and tuck them in so that there are no hanging ends. Wear safety shoes and PPE.
2.2. Check availability and serviceability:
— devices;
— live parts of electrical equipment (starters, switches, switches);
— tools, devices;
— serviceability of grounding.
2.3. Make sure that the switch and switches are in the “Off” position.
2.4. Inspect equipment, fixtures, tools.
2.5. In case of detection of malfunctions that cannot be eliminated on your own, please report this to your immediate supervisor. Do not begin work until identified violations are eliminated.

3. OCCUPATIONAL SAFETY REQUIREMENTS DURING WORK

3.1. Work only with serviceable devices, tools, accessories and use them strictly for their intended purpose.
3.2. To avoid electrical injury, do not touch uninsulated live parts of the equipment. Action AC begins to appear at a current value of 1 mA and is felt as a slight itching on the skin of the fingers touching the conductor. A current value of 25-50 mA is life-threatening.
3.3. All connections of devices that require breaking electrical circuits must be made with the voltage removed.
3.4. Connect any devices to electrical network only be carried out using special connectors, electrical plugs.
3.5. During work, the workplace must be kept in order, the workplace must not be cluttered with parts and waste, and cleaning must be carried out periodically.
3.6. When leaving the workplace, even for a short time, turn off the devices and electronic unit on which work is being performed.
3.7. It is prohibited to leave the workplace with the devices and electronic unit turned on.

4. OCCUPATIONAL SAFETY REQUIREMENTS IN EMERGENCIES

4.1. In the event of an accident, it is necessary to immediately provide assistance to the victim. report the incident to the administration, call ambulance by calling 103 (if necessary), keep the situation as it was at the time of the incident (if this does not threaten the life and health of workers and does not lead to a further accident).
4.2. If a fire occurs, call the fire brigade by calling 101, report the incident to the administration and begin extinguishing the fire using the available primary fire extinguishing equipment.
4.3. In the event of an electrical equipment fire, you must:
— de-energize electrical equipment;
— extinguish with OU-2 fire extinguishers; OU-5; OU-8 or dry sand.
4.4. In case of electric shock, you must:
- immediately release the victim from the effects of electric current by turning off the switch;
- if it is remote, it is necessary to separate the victim from live parts, using insulating objects, dielectric gloves or non-conductive material to protect hands;
— it is not allowed to touch the victim or live parts with bare hands;
- a victim under the influence of electric current may be pulled away only with one hand, previously insulated with non-conductive material;
- in the absence of breathing and pulse in the carotid artery, immediately begin resuscitation: free the chest from clothing that restricts breathing and unfasten the waist belt; lay the victim on his back, tilt his head back and place a cushion under his neck; restore airway patency, freeing the mouth from mucus and foreign bodies; begin indirect cardiac massage and artificial respiration, first striking the sternum with a fist (it is prohibited to strike if there is a pulse);
- indirect cardiac massage is performed with a pressing frequency of approximately 1 time per second to a depth of pressing the chest by 3-4 cm. When performing indirect cardiac massage, it is necessary to stand on the side of the victim and, placing your palms on the lower part of the sternum, apply pressure with sharp pushes;
- during artificial respiration, with the head thrown back, it is necessary to pinch the victim’s nose with your fingers and exhale as much as possible into his mouth through gauze (napkin, handkerchief) every 5-6 minutes;
— when providing assistance by one rescuer, every 2 exhalations into the victim’s mouth, apply 15 pressures on the sternum;
- continue resuscitation until full recovery cardiac activity or until paramedics arrive. If there is no consciousness, but there is a pulse, turn the victim onto his stomach and in this position wait for the doctors to arrive;
- It is forbidden to leave the victim lying on his back.

5. LABOR SAFETY REQUIREMENTS AFTER COMPLETION OF WORK

5.1. Disconnect voltage from the radio-electronic unit, instruments, and soldering iron.
5.2. Place the tool, equipment, and soldering iron in the designated place.
5.3. Tidy up your workspace
5.4. Treat the workplace where soldering work was carried out with a 5% solution of acetic acid.
5.5. Notify the supervisor of any comments identified.
5.6. Neutralize the lead contained in the solder by washing your hands with a 5% solution of acetic acid, wash your face and hands with warm water and soap.

Remote control of moving models is based on interaction between a person and a model. The pilot sees the position of the model in space and its speed. Using remote control equipment, he gives commands to the model’s actuators, which turn the rudders or control the engines, thereby the pilot changes the position and direction of the model’s movement in accordance with his desire. The transmission of commands from the pilot to the model occurs mostly via radio. An exception can be found only for indoor models, where infrared radiation is used along with radio, and ultrasound is also very rarely used to control underwater vehicles.

The radio control equipment consists of a transmitter, which is located by the pilot, and a receiver and actuators located on the model. This article will help you gain an understanding of how a transmitter works and which transmitter you need.

Design types of transmitters

Based on the design of the controls, which are actually acted upon by the pilot’s fingers, transmitters are divided into joystick and pistol type. The first ones usually have two two-axis joysticks. Such transmitters are used to control flying models. In joystick transmitters, the handle has built-in springs that return it to the neutral position when released. As a rule, one of the directions of some kind of joystick is used to control the traction motor - it does not have a return spring. In this case, the handle is pressed with a ratchet (for airplanes) or a smooth braking plate (for helicopters). Using such transmitters, you can also successfully control floating and driving models, but special pistol-type transmitters have been invented for them. Here the steering wheel controls the direction of movement of the model, and the trigger controls its engine and brakes.

In recent years, transmitters with a single two-axis joystick have appeared. They belong to the category of cheap devices and can be used to control both simplified flying and ground equipment. They can be used productively only at the most basic level. Transmitters with two single-axis joysticks have a similar purpose:

To finish with design variations, let’s add a division of joystick transmitters into monoblock and modular. If the first ones are fully equipped with all components and are immediately ready for use, then the modular ones represent a basis into which the pilot, at his discretion, adds the additional controls he needs:

There are two ways to hold the transmitter. Remote control transmitters are hung around the pilot's neck using a special belt or stand. The pilot's hands rest on the transmitter body, and each joystick is controlled by two fingers - the index and thumb. This is the so-called European school. The pilot holds the handheld transmitter in his hands, and each joystick is controlled by one thumb. This manner is attributed to the American school.

The handheld transmitter can also be held in your hands and controlled in a European way. You can also use it in a remote control version if you buy a special table-stand for it. You can make a table no worse than a branded one yourself. Such tables are also required for some remote control transmitters. Which style is more common among us depends on the age of the pilot. Young people, according to our observations, are more inclined to American customs, and the older generation is more inclined to the conservatism of Europe.

Number of channels and control knob layout

Controlling moving models requires influencing several functions simultaneously. Therefore, radio control transmitters are made multi-channel. Let's consider the number and purpose of channels.

For cars and ship models, two channels are needed: control of the direction of movement and engine speed. Sophisticated pistol transmitters also have a third channel, which can be used to control the mixture formation of the internal combustion engine (radio needle).

To control the simplest flying models, two channels can also be used: elevators and ailerons for gliders and airplanes, or elevators and rudder. For hang gliders, roll control and motor power are used. This scheme is also used on some simple gliders - rudder and engine switching on. These two-channel transmitters can be used for fleet models and entry-level electric aircraft. However, to fully control an airplane you need at least four, and a helicopter - five channels. For aircraft, two two-axis joysticks provide control functions for the elevator, direction, ailerons and engine throttle. The specific layout of functions for joysticks is of two types: Mode 1 - elevator on the left vertically and rudder horizontally, gas on the right vertically and roll horizontally; Mode 2 - gas on the left vertically and rudder horizontally, elevator on the right vertically and roll horizontally. There are also Mode 3 and 4, but they are not very common.

Mode 1 is also called the two-handed version, and Mode 2 is called the one-handed version. These names follow from the fact that in the latter version you can control the plane for quite a long time with one hand, holding a can of beer in the other. Modellers' debate about the advantages of one scheme or another has not subsided for many years. For the authors, these disputes are reminiscent of the debate about the advantages of blondes over brunettes. In any case, most transmitters can easily be switched from one layout to another.

To effectively control a helicopter, you already need five channels (not counting the channel for controlling the sensitivity of the gyroscope). Here there is a combination of two functions per direction of the joystick (we will look at how this happens later). The handle layouts are in many ways similar to airplane ones. Among the features is the throttle stick, which some pilots invert (minimum throttle is at the top, maximum throttle is at the bottom), as they find it more convenient.

Above, we considered the minimum required number of channels to control the movement of models. But there can be a lot of functions for managing models. Especially on replica models. On airplanes, this can be control of landing gear retraction, flaps and other wing mechanization, side lights, and landing gear wheel brakes. More more features in replica ship models that imitate various mechanisms real ships. Gliders use control of flaperons and air brakes (interceptors), retractable landing gear and other functions. Helicopters also use control over the sensitivity of the gyroscope, retractable landing gear, and others. additional functions. To control all these functions, transmitters are available with a number of channels of 6, 7, 8 and up to 12. In addition, modular transmitters have the ability to increase the number of channels.

It should be noted here that control channels are of two types - proportional and discrete. The easiest way to explain this is in a car: gas is a proportional channel, and headlights are discrete. Currently, discrete channels are used only to control auxiliary functions: turning on the headlights, releasing the landing gear. All main control functions are carried out through proportional channels. In this case, the amount of steering wheel deflection on the model is proportional to the amount of joystick deflection on the transmitter. So, in modular transmitters it is possible to expand the number of both proportional and discrete channels. We will look at how this is done technically later.

There is one fundamental ergonomic problem associated with multichannel. A person has only two hands, which can control only four functions at a time. On real airplanes, pilots' feet (pedals) are also used. Modelers have not yet come to this conclusion. Therefore, the remaining channels are controlled from individual toggle switches for discrete channels or knobs for proportional ones, or these auxiliary functions are obtained by calculation from the main ones. In addition, the model control signals may also not be directly controlled from the joysticks, but undergo pre-processing.

Control signal processing and mixing

After reading the previous chapters, we hope you were able to understand two main points:

• The transmitter can be held in different ways, but the main thing is not to drop it
• There are many channels in transmitters, but you always need to control them with only two hands, which is sometimes not very easy

Now that we have a preliminary understanding, let's consider a few more practical points that transmitters implement:

• trimming
• adjusting the sensitivity of the knobs
• channel reverse
• limitation of steering gear costs
• mixing
• other functions

Trimming is a very important thing. If you release the transmitter handles while driving the model, the springs will return them to the neutral position. It is quite logical to expect that the model will move straight. However, in practice this is not always the case. There are many reasons for this. For example, if you are launching a newly built aircraft, then you may incorrectly take into account the torque from the engine, and in general the model is rarely perfectly symmetrical and correct in shape. As a result, even if the rudders appear to be level, the model will still not fly straight, but in some other way. To correct the situation, the position of the steering wheels will need to be adjusted. But it is quite clear that doing this directly on the model during launches is very impractical. It would be much easier to slightly move the transmitter handles in the desired directions. This is exactly why trimmers were invented! These are small additional levers on the sides of the joysticks that set their displacement. Now, if you need to adjust the neutral position of the rudders on the model, you just need to use the desired trimmer. Moreover, what is especially valuable is that trimming can be carried out right on the go, during launches, observing the reaction of the model. If you find that initially the model does not need trimming, consider yourself very lucky.

Adjusting the sensitivity of the knob is a completely understandable function. When you set up controls for specific model, you need to set the sensitivity so that the control is most comfortable for you. Otherwise, the model will respond to the transmitter knobs too sharply or, on the contrary, too sluggishly. More “advanced” models allow you to set an exponential sensitivity function for the transmitter knobs in order to more accurately “steer” with slight deviations.

If we now think back to the model, we will find that depending on how the steering gears are installed and how the linkages are connected, we may need to change their direction of operation. To achieve this, all transmitters allow independent reversal of control channels.

The mechanics of the model itself may have limitations, so sometimes it is necessary to limit the stroke of the steering gears. To achieve this, many transmitters have a separate travel limitation function, although if it is missing, you can try to get by by adjusting the sensitivity of the knobs.

Now it's time to touch on more complex aspects and tell you what mixing is.

Sometimes it may be necessary for the steering wheel on a model to be controlled simultaneously from several transmitter handles. A good example is a flying wing, where both ailerons control the height and roll of the model, i.e. the movement of each depends on the movement of the altitude stick and roll stick on the transmitter. Such ailerons are called elevons:

When we control the height, both elevons deflect simultaneously up or down, and when we control the roll, the elevons work in antiphase.

The elevon signals are calculated as a half-sum and half-difference of the altitude and roll signals:

Elevon1 = (height + roll) / 2
Elevon2 = (height - roll) / 2

Those. The signals from the two control channels are mixed and then transmitted to the two execution channels. Such calculations, which involve input from multiple control knobs, are called mixing.

Mixing can be implemented both in the transmitter and on the model. And the implementation itself can be either electronic or mechanical.

Especially for beginners (with the exception of helicopter pilots), I would like to note that the models you will start with will most likely not require mixers for their operation. Moreover, you may not need mixers for very long (or maybe you will never need them at all). So if you decide to buy yourself a simple 4-channel joystick equipment, or 2-channel pistol equipment, then you shouldn’t be upset about the missing mixers.

You'll find a ton of other features in good transmitters in the upper price range. The extent to which they are needed for a particular model is a debatable issue. To get an idea about them, you can read the descriptions of such transmitters on the manufacturers’ websites.

Analog and computer transmitters

To understand the difference between analog and computer transmitters, let's look at a more realistic example. About fifteen years ago, programmable phones began to spread. They differed from the usual ones in that, in addition to conversation and identifying the number of the calling subscriber, they made it possible to program one button to dial an entire number, or create a “black list” of subscribers to whose calls the phone did not respond. A bunch of additional services have appeared that to a simple subscriber were often not needed. So, an analog transmitter is like a simple telephone. It usually has no more than 6 channels. As a rule, the simplest of the services described above are implemented: there is channel reversal (sometimes not all), trimming and sensitivity adjustment (usually on the first 4 channels), setting the extreme values ​​of the throttle channel (idle and maximum speed). Adjustments are made using switches and potentiometers, sometimes using a small screwdriver. Such devices are easy to learn, but their operational flexibility is limited.

Computer equipment is characterized by the fact that all settings in them can be programmed using buttons and a display in the same way as on programmable phones. There can be a lot of services here. The main ones worth noting are the following:

1. Availability of memory for several models. A very convenient thing. You can remember all the settings for mixers, reverses and rates, so you don’t have to rebuild the transmitter when you decide to use it with another model.
2. Memorizing trim values. A very convenient feature. You don't have to worry that the trimmers will accidentally get knocked down during transportation and you'll have to remember their position. Before starting the model, it will be enough to just check that the trimmers are installed “in the center”.
3. A large number of built-in mixers and operating mode switches will allow you to implement a wide variety of functions on complex models.
4. The presence of a display makes it much easier to configure the equipment.

The number of functions and price of computer equipment varies quite widely. It’s best to always look at the manufacturer’s website or instructions for specific features.

The cheapest devices may come with a minimum of functions and are primarily focused on ease of use. These are primarily model memory, digital trimmers and a couple of mixers.

More complex transmitters usually differ in the number of functions, expanded display and additional modes data encoding (to protect against interference and increase the speed of information transfer).

Top models of computer transmitters have graphic displays large area, in some cases even with touch control:

It makes sense to buy such models for ease of use or for some particularly tricky functions (which may only be needed if you want to seriously engage in sports). Sophistication leads to the fact that top models already compete with each other not in the number of functions, but in ease of programming.

Many computer transmitters have replaceable modules model settings memory, which allows you to expand the built-in memory, as well as easily transfer model settings from one transmitter to another. A number of models provide for changing the control program by replacing a special board inside the transmitter. In this case, you can change not only the language of the menu prompts (the authors have not encountered Russian, by the way), but also install a more recent one in the transmitter software with new possibilities.

It should be noted that flexibility in the use of computer equipment also has negative features. One of the authors recently gave his mother-in-law a programmable phone, so she tinkered with programming it for a week and returned it with a request to buy her a simple, as she says, “normal phone.”

Principles of radio signal generation

Now we will move away from the problems of modeling and consider issues of radio engineering, namely, how information from the transmitter gets to the receiver. For those who do not really understand what a radio signal is, you can skip this chapter, paying attention only to the important recommendations given at the end.

So, the basics of model radio engineering. In order for the radio signal emitted by the transmitter to carry useful information, it undergoes modulation. That is, the control signal changes the parameters of the radio frequency carrier. In practice, control of the amplitude and frequency of the carrier, denoted by the letters AM (Amplitude Modulation) and FM (Frequency Modulation), has been used. Radio control uses only discrete two-level modulation. In the AM version, the carrier has either a maximum or zero level. In the FM version, a signal of constant amplitude is emitted, either with a frequency F, or with a slightly shifted frequency F + df. The FM transmitter signal resembles the sum of two signals from two AM transmitters operating in antiphase at frequencies F and F +df, respectively. From this it can be understood, even without delving into the intricacies of radio signal processing in the receiver, that under the same interference conditions, an FM signal has fundamentally greater noise immunity than an AM signal. AM equipment is usually cheaper, but the difference is not very large. Currently, the use of AM equipment is justified only in cases where the distance to the model is relatively small. As a rule, this is true for car models, ship models and indoor aircraft models. In general, you can fly using AM equipment only with great caution and away from industrial centers. Accidents are too expensive.

Modulation, as we have established, allows useful information to be superimposed on the emitted carrier. However, radio control uses only multi-channel information transmission. To do this, all channels are compressed into one through coding. Currently, only pulse-width modulation, denoted by the letters PPM (Pulse Phase Modulation) and pulse-code modulation, denoted by the letters PCM (Pulse Code Modulation), are used for this. Due to the fact that the word "modulation" is used to refer to coding in multi-channel radio control and to superimpose information on the carrier, these concepts are often confused. Now it should become clear to you that these are “two big differences,” as they like to say in Odessa.

Let's consider a typical PPM signal of five-channel equipment:

The PPM signal has a fixed period length T=20ms. This means that information about the positions of the control knobs on the transmitter reaches the model 50 times per second, which determines the speed of the control equipment. As a rule, this is enough, since the pilot’s reaction speed to the model’s behavior is much slower. All channels are numbered and transmitted in numerical order. The value of the signal in the channel is determined by the time interval between the first and second pulse - for the first channel, between the second and third - for the second channel, etc.

The range of changes in the time interval when moving the joystick from one extreme position to another is defined from 1 to 2 ms. A value of 1.5 ms corresponds to the middle (neutral) position of the joystick (control stick). The duration of the interchannel pulse is about 0.3 ms. This PPM signal structure is standard for all manufacturers of RC equipment. The average handle position values ​​may differ slightly from one manufacturer to another: 1.52 ms for Futaba, 1.5 ms for Hitec and 1.6 for Multiplex. The range of variation for some types of computer transmitters can be wider, reaching from 0.8 ms to 2.2 ms. However, such variations allow the mixed use of hardware components from different manufacturers operating in PPM encoding mode.

As an alternative to PPM coding, PCM coding was developed about 15 years ago. Unfortunately, various manufacturers of RC equipment could not agree on a single format for the PCM signal, and each manufacturer came up with their own. More details about the specific formats of PCM signals from equipment from different companies are described in the article “PPM or PCM?”. The advantages and disadvantages of PCM coding are also given there. Here we will only mention the consequence various formats: In PCM mode, only receivers and transmitters from the same manufacturer can be used together.

A few words about the designations of modulation modes. Combinations of two types of carrier modulation and two coding methods give rise to three options for equipment modes. Three because amplitude modulation It is not used in conjunction with pulse code - there is no point. The first has too poor noise immunity, which is the main purpose of using pulse-code modulation. These three combinations are often referred to as: AM, FM and PCM. It is clear that in AM - amplitude modulation and PPM coding, in FM - frequency modulation and PPM coding, but in PCM - frequency modulation and PCM coding.

So now you know that:

• the use of AM equipment is justified only for car models, ship models and indoor aircraft models.
• Flying using AM equipment is only possible with great caution and away from industrial centers.
• You can use hardware components from different manufacturers operating in PPM encoding mode.
• In PCM mode, only receivers and transmitters from the same manufacturer can be used together.

Modular expansion

Modular transmitters are produced mainly in remote control versions. In this case, there is a lot of space on the remote control panel where you can place additional knobs, toggle switches and other controls. Among other cases, we will mention a module for controlling a twin-engine boat or tank. It is installed instead of a two-axis joystick and is very similar to the clutch levers of a crawler tractor. With its help you can deploy the following models on a patch:

Now we will explain how channels are compacted with a modular expansion of their number. Various manufacturers modules are produced that allow up to 8 proportional or discrete additional channels to be transmitted over one main channel. In this case, an encoder module with eight knobs or toggle switches is installed in the transmitter, occupying one of the main channels, and a decoder with eight proportional or discrete outputs is connected to the receiver in the slot of this channel. The principle of compaction comes down to sequential transmission through this main channel of one additional channel in every 20 millisecond cycle. That is, information about all eight additional channels from the transmitter to the receiver will reach only after eight signal cycles - in 0.16 seconds. For each decompressed channel, the decoder produces an output signal as usual - once every 0.02 seconds, repeating the same value eight times. From this it can be seen that compacted channels have much lower performance and it is inappropriate to use them to control fast and important functions model control. In this way, you can create 30-channel equipment sets. What is this for? As an example, here is a list of functions of the lighting and signaling module of a replica model of a mainline tractor:

• Side lights
• High beam
• Low beam
• Finder headlight
• Stop light
• Engaging reverse gear (the last two functions are activated automatically from the throttle control position)
• Left turn
• Right turn
• Cabin lighting
• Klaxon
• Flashing beacon

Modular transmitters are more often used by copyists, for whom the spectacular behavior of the model, the realism of how it looks, and not its dynamics of behavior are more important. Available for modular transmitters large number various modules for specific purposes. We will only mention here the aileron trimming unit for aerobatic models. Unlike monoblock transmitters, where control parameters in the “flaperon” modes, the air brake (in our opinion “crocodile”, and in the West “butterfly”) and differential deviation are programmed in the menu, here each parameter is displayed on its own knob. This allows you to make adjustments directly in the air, i.e. without taking his eyes off the flying model. Although this is also a matter of taste.

Transmitter device

The radio control equipment transmitter consists of a housing, controls (joysticks, knobs, toggle switches, etc.), an encoder board, an RF module, an antenna and a battery. In addition, the computer transmitter has a display and programming buttons. Explanations on the body and controls were given above.

The encoder board contains the entire low-frequency circuit of the transmitter. The encoder sequentially polls the position of the controls (joysticks, knobs, toggle switches, etc.) and, in accordance with it, generates channel pulses of the PPM (or PCM) signal. All mixing and other services (exponent, stroke limitation, etc.) are also calculated here. From the encoder, the signal goes to the RF module and the trainer connector (if there is one).

The RF module contains the high-frequency part of the transmitter. The questioner is assembled here crystal oscillator, which determines the channel frequency, frequency or amplitude modulator, amplifier-output stage of the transmitter, antenna matching circuits and filtering out-of-band emissions. In simple transmitters, the RF module is assembled on a separate printed circuit board and is located inside the transmitter housing. In more advanced models, the RF module is housed in a separate housing and is inserted into a niche on the transmitter:

In this case, there is no replaceable quartz, and the radio signal carrier is formed by a special frequency synthesizer. The frequency (channel) at which the transmitter will operate is set using switches on the RF unit. Some top transmitter models can set the synthesizer frequency directly from the programming menu. Such capabilities make it possible to easily distribute pilots to different channels in any combination of races and rounds of competition.

Almost all radio control transmitters use a telescopic antenna. When unfolded it is quite effective, and when folded it is compact. In some cases, it is possible to replace the standard antenna with a shortened helical antenna, produced by many companies, or with a homemade one.

It is much more convenient to use and more durable in the hustle and bustle of competition. However, due to the laws of radio physics, its efficiency is always lower than that of a standard telescopic one, and it is not recommended for use for flying models in complex interference environments in large cities.

During use, the telescopic antenna must be extended to its full length, otherwise the communication range and reliability drop sharply. With the antenna folded, before flights (races), the reliability of the radio channel is checked - the equipment should work at a distance of up to 25-30 meters. Folding the antenna usually does not damage the operating transmitter. In practice, there have been isolated cases of the RF module failing when folding the antenna. Apparently, they were caused by low-quality components and could have happened with the same probability regardless of the folding of the antenna. And yet, the telescopic antenna of the transmitter does not radiate the signal well in the direction of its axis. Therefore, try not to point the antenna at the model. Especially if it is far away and the interference environment is bad.

Most even simple transmitters a “trainer-student” function is provided, allowing a novice pilot to be trained by a more experienced one. To do this, two transmitters are connected with a cable through a special “trainer” connector. The trainer's transmitter is switched to radio signal emission mode. The student's transmitter does not emit a radio signal, but the PPM signal from his encoder is transmitted via cable to the trainer's transmitter. The latter has a “trainer-student” switch. In the “trainer” position, a signal about the position of the trainer transmitter handles is transmitted to the model. In the "student" position - from the student transmitter. Since the switch is in the hands of the trainer, he takes over control of the model at any moment and thereby protects the beginner, preventing him from “making wood.” This is how flying model pilots are taught. The trainer connector contains the output of the encoder, the input of the trainer-student switch, ground, and the power control contacts of the encoder and the RF module. On some models, connecting the cable turns on the encoder's power while the transmitter's power is off. In others, shorting the control contact to ground turns off the RF module when the transmitter power is turned on. In addition to the main function, the trainer connector is used to connect the transmitter to a computer when used with a simulator.

The power supply for the transmitters is standardized and is supplied from a nickel-cadmium (or NiMH) battery with a nominal voltage of 9.6 volts, i.e. from eight cans. The battery compartment in different transmitters has different size, which means that the finished battery from one transmitter may not fit another in size.

The simplest transmitters can use ordinary disposable batteries. For regular use this is ruinous.

Top models of transmitters may have additional components useful to the modeler. Multiplex, for example, in its 4000 model integrates a panoramic scanning receiver, which allows you to see the presence of emissions in the frequency range before flights. Some transmitters have a built-in (with remote sensor) tachometer. There are options for a coaching cable made on the basis of optical fiber, which galvanically decouples the transmitters and does not create interference. There are even means of wirelessly connecting a trainer with a student. Many computer transmitters have replaceable memory modules that store information about the model settings. They allow you to expand the set of programmed models and transfer them from transmitter to transmitter.

So now you know that:

• by replacing quartz, you can change the channel of the equipment within the operating range
• By replacing the replaceable RF module, it is easy to switch from one band to another.
• RF modules are designed to work with only one type of modulation: amplitude or frequency.
• During use, the telescopic antenna must be extended to its full length, otherwise the communication range and reliability drop sharply.
• Folding the antenna does not damage the operating transmitter.

Conclusion

After reading brief introduction On the topic of radio control equipment transmitters, you have roughly imagined which transmitter you need. However, the variety of market offers does not make the problem of choice easier, especially at the beginning of radio modeling. Let us give you some advice on this matter.

The radio control transmitter is the most enduring part of all things modeling. It is in the hands of the pilot, and does not rush around at terrible speed, trying to injure those around him and the model itself with all its contents. If you do not reverse the polarity of the transmitter battery, do not step on it or drop it on the floor, then it can faithfully serve for years and decades. If you are engaged in modeling not alone, but together with a close friend, you can generally purchase one transmitter for two. Since the transmitter is a durable component, it is better to purchase a good device right away. It won't be cheap, but it will cover your growing needs over time, and you won't have to sell it a year later for half the price because it's missing any mixers or other features. But you shouldn’t go to extremes and immediately buy a device in the upper price range. The transmitters for champion athletes contain capabilities that will take years to understand and use. Think about whether you need to pay extra money for prestige.

According to the authors' experience, the quality of transmitters depends on their price group. Apparently, at manufacturing plants, more expensive models are more strictly controlled both during assembly and at the stage of purchasing components. An unprovoked failure of a transmitter is generally an extremely rare thing, but in expensive models- almost never found.

For expensive transmitters, special aluminum cases are produced that are used for storage and transportation to the airfield. For cheaper devices, you can purchase a special plastic box, or make it yourself. Such special packaging should not be neglected by those who regularly (weekly) go on flights or races. It will more than once save your favorite transmitter from shock and destruction, which has served you for many years and may be inherited by your son.

Adjustment of radio-electronic equipment and devices

Carrying out adjustment work is associated with great responsibility, since it completes the manufacture of the product. Therefore, it is important that the adjuster thinks through his actions in advance before performing any operations that become necessary during the adjustment process. Such operations include, in particular, the replacement of individual assembly units and parts. The scope of dismantling, assembly and installation work is usually small, but ensuring high quality their implementation is an immutable law. Particular attention should be paid to dismantling work, during which the solder leads of elements that have additional mechanical fastenings are released. These operations require special attention and careful execution, otherwise peeling of printed conductors, failure of microcircuits, burning of the insulation of overhead conductors, and breakage of leads may occur.

Work related directly to product adjustment in serial and mass production conditions is determined by technical documentation - technological maps or adjustment instructions. At the stages of developing prototypes and experimental series, the regulator must reject technical documentation for adjustment, determine the most productive methods of the adjustment sequence, as well as the limits of the nominal values ​​of the elements selected in this case, identify defects in the design and production process.

Before starting to adjust the measuring equipment, the adjuster must carefully study the technical data of the devices, the rules of their operation and be able to use them in practice.

Before you begin connecting the regulated product with power supplies and measuring instruments, you must ensure that they are in good working order and are available. normal stress nutrition. Checking the presence of normal supply voltages, and sometimes the level of their ripples, is carried out directly at the input of the power circuits of the regulated product.

One of the reasons for errors during adjustment may be the incorrect choice of cable from the kit to the measuring device. One of these cables may be open at the end, another may be loaded with a resistance of 50 or 75 Ohms, the third may have a built-in detector head, and the fourth may have a built-in filter or series resistance. The wrong choice of cable inevitably leads to gross errors and sometimes to disruption of the functioning of the controlled product.

Another reason for errors may be an open circuit in the cable or connecting wires, as well as broken contacts in the connectors connecting the cables on one side to measuring instruments or power supplies, and on the other to the controlled device. There are various ways to check the serviceability of connecting devices, the simplest of which is to replace the questionable cable with a working one. Poor contact in the connectors is detected by slight rocking or slight movement of the moving part of the connector.

1) tuning one or more circuits to a fixed frequency (in intermediate frequency stages, blocking filter circuits and in radio receivers with a fixed tuning);

Lecture 5

1. PURPOSE AND TYPES OF ADJUSTMENTS

In the process of manufacturing and operating radio-electronic equipment (REA) to obtain best quality When receiving and transmitting a signal, it is necessary to regulate a number of its indicators: tuning frequency, gain, bandwidth, etc. To carry out these adjustments, regulators are used in the RPU. Depending on the type of the adjustable parameter, there are: gain control, which can be carried out in the radio frequency and intermediate frequency paths, as well as in the post-detector part of the receiver; adjustment of the tuning frequency, ensuring reception of signals in a wide range of frequencies; adjustment of the bandwidth, which can be carried out in the radio frequency and intermediate frequency paths, as well as in the post-detector part of the receiving device. Cascades with electrically controlled transmission coefficient are used in the receiving units of all echo-pulse ultrasonic and hydroacoustic systems. In ultrasonic systems these cascades are used.

Adjustment can be manual or automatic. Manual adjustment is used to set the initial REA indicators. Automatic gain control (AGC), TAGC (temporary automatic gain control), BARU (high-speed AGC) maintain selected REA indicators at the required level. Some types of adjustments can be classified as mixed. In modern electronic equipment, microprocessors are widely used for adjustment, control and monitoring.

2. GAIN ADJUSTMENT

Methods for adjusting the gain of a resonant amplifier. Resonant gain of the amplifier according to the circuit in Fig. 13.1 is determined by the formula:

Ko = S Ke m 1 m 2 (5.26),

where m 1 and m 2 are inclusion factors; S is the slope of the transistor at the operating point; Ke is the equivalent resistance of the circuit at resonance, taking into account the shunting effect of the transistor output and the input of the subsequent cascade. Adjustment of Ko can be carried out by changing any value included in formula (5.26). When synthesizing control devices, a significant change in Ko from the control voltage Eper, a small regulation current, and a small dependence of changes in other parameters of the amplifier when changing Ko are required. The considered methods of changing the gain are applicable for both manual and automatic adjustments. Adjustment by changing the slope. Such adjustment is carried out by changing the mode of the electronic device; accordingly, such adjustment To is called mode adjustment. To change the slope S, it is necessary to change the bias voltage on the control electrode of the electronic device: voltage Ubeo in bipolar or voltage Uzio in field-effect transistors. A change in voltage Ubeo across the transistor causes a significant change in the bias voltage.

When the bias in a field-effect transistor changes, almost only the slope S changes, and in bipolar transistor also such parameters as h 11, h 22, etc. The regulating voltage Eper is supplied to the emitter circuit or to the base circuit of the transistor. The first type of adjustment diagram is shown in Fig. 13.1, a, bias voltage on the transistor UBeo = U0 - Ureg. As Uper increases, the voltage Ubeo decreases, which entails a decrease in the current Iko and slope S, as a result of which the gain Ko decreases. The regulation circuit should provide a current approximately equal to Ieo. If regulated n cascades, then the control current Iper is equal to the sum of Iper n, therefore the control circuit should produce relatively high current Iper, which is a disadvantage of the circuit in Fig. 13.1, a. The control circuits of the second type, in which the voltage Ureg is introduced into the base circuit, are free from this drawback (Fig. 13.1.6). According to Fig. 13.1.6 IBEO = Io - Ipeg, therefore the adjustment principle is the same in both cases. The advantage of adjustment according to the diagram in Fig. 13.1.6 is that the current I per, equal to the divider current Idl = (5 - 10) IBO > is many times less than the current Iper when adjusted according to the diagram in Fig. 13.1, i. However, the diagram in Fig. 13.1.6 is less stable in operation, since it does not have a resistor in the emitter circuit Ry. The inclusion of resistor Ry leads to a decrease in the efficiency of regulation, since it ensures stabilization of the mode not only when the temperature changes, but also when Eper changes. When turning on the resistor RE, to ensure the same depth of adjustment, it is necessary to apply a larger voltage value Eper.

Adjustment by changing Req.

This adjustment can be made in various ways. In Fig. Figure 13.2 shows a judging circuit with a diode D connected in parallel to the circuit. When Ereg > Us, the diode is closed and the circuit practically does not shunt; at the same time Req and Ko are the greatest. When Eper< US диод открывается и его входное cсопротивление шунтирует контур. В этом случае Ry, а следовательно, Ко уменьшаются. Основной недостаток такого способа регулировки остоит в том, что при изменении Rэкв, меняется не только Ко, но и квивалентное затухание контура, а это вызывает изменение полосы пропускания усилителя.

Rice. 13.2 Fig. 13.3

However, with a strong signal, some degradation in selectivity is acceptable. Adjustment by changing m1 and Z. Idea this method adjustments are explained in Fig. 13.3. The voltage from the circuit is supplied to the divider Z1Z2, changing one of the resistances of which you can change the switching factor. The scheme for changing mi is similar. Coils with variable inductance or capacitors with variable capacitance. However, this adjustment method is not used, since it is associated with a difficult to prevent detuning of the circuit that occurs when the resistances Z1 and Z2 change.

Attenuator adjustment.

With this adjustment method, an attenuator with a variable transmission coefficient is included between the amplifier stages. Adjustable dividers, capacitive dividers on varicaps, and bridge circuits are used. So, in Fig. 13.4, and shows the circuit of an adjustable attenuator using diodes D1 - D3. When | Eper I< V/o Диоды Д1 и Д2 открыты, а диод Д3 закрыт; при этом коэффициент передачи максимален. По мере уве­личения Ерег динамические сопротивления диодов Д1 и Д2 увеличи­ваются, а динамическое сопротивление диода Д3 уменьшается, а следо­вательно, уменьшается коэффициент передачи аттенюатора. На рис. 13.4,6 представлена схема делителя, в которой в качестве управляемого сопротивления применяют field effect transistor; under the influence of Ereg, the resistance of the transistor channel changes. Attenuators based on pin diodes, which have a large resistance range and low capacitance, are widely used. In Fig. 13.4, c shows an attenuator circuit using pin diodes, the operation of which is controlled by changing the bias on the base of the transistor Ti using a resistor Rper. At zero control voltage, diodes D1 and D are closed, and Dz is open and the attenuator attenuation is minimal. At maximum voltage adjustment diodes D1 and DD are open, and Dz is closed and the attenuator attenuation is maximum.

Adjustment of Ko using adjustable OOS. This method of adjusting Ko, like attenuator adjustment, does not follow from formula (5.26). Typical scheme changes in the regulated environment are shown in Fig. 13.5, OOS in this case is introduced into the emitter circuit of the transistor. In amplifier stages, a capacitor C is usually included in parallel with R, large capacity to eliminate OOS. In the diagram of Fig. 13.5, the depth of the OOS can be adjusted by changing the capacitance of the capacitor Creg; blocking capacitor Cbl, used for separation by DC transistor regulation and power circuits. Varicap D is usually used as Creg. As Ereg increases, diode D closes more strongly, its capacitance Creg decreases, the OOS voltage increases, and the gain Co decreases.