Diagram of a lamp burnout indicator in a car. Electric circuit of the scooter. For the scheme "On the use of fluorescent lamps with burnt filaments"

In cars, especially older used ones, there are times when headlights or taillights burn out. And if the burnout of the headlight can still be noticed in a timely manner, since its light, especially at night, is clearly visible to the driver, then it is difficult to notice the rear one. If such a breakdown is not eliminated in a timely manner, you can get a fine or create an emergency. Therefore, the presented scheme allows you to detect a malfunction of a car headlight, for example, a taillight in time, in order to timely fix the problem and thereby avoid a fine.

This electrical circuit is assembled from a small number of simple discrete components and is oriented to a voltage of 12 V, which is the standard for passenger cars.

The basis of this circuit is the optocoupler TLP521-1 (PC1). It consists of an LED and a phototransistor. Its isolation voltage is 2.5KV, the maximum forward current is 70mA, and the maximum output voltage is 55V, and the on/off time is 3ms. This, of course, is not the best optocoupler, but for this application it will fit perfectly. Moreover, it is very cheap, it costs only about 20 rubles. In the optocoupler circuit, PC1 monitors the status of the connected headlight. When a car headlight turns on, current flows through the headlight and the 1N5401 diodes (D1 and D2). Due to this, the LED in the optocoupler lights up, and as a result, the optocoupler turns off the transistor BC559 (T1).

T1 is a PNP type silicon bipolar transistor. If the BC559 is not at hand, then you can take the closest analogue, which would be closest in parameter to this transistor. Its maximum allowable collector-base voltage is 30 V, the maximum allowable collector-emitter voltage is 25 V, the maximum allowable emitter-base voltage is 5 V, and the maximum direct collector current is 0.2 A. This transistor is located in the TO226 package. As the closest analogues, you can take KT3107, 2N6003 or BC179V.

In the event of a headlight failure, the optocoupler is switched off instantly and a warning red 5 mm LED (LED1) is switched on via transistor T1. Resistor R3 limits the operating current of LED1, and resistor R2 (optimally 100 kΩ) determines the switching threshold T1.

The circuit can be quite easily assembled on a small piece of textolite. In the future, it is desirable to place it in a small plastic case, which can be easily attached somewhere near the dashboard in a conspicuous place.

Electronics for the car

V. KHROMOV, Krasnoyarsk
Radio, 2002, No. 2

The sensor in control devices is usually a current measuring resistor, which often limits their use, for example, due to the large voltage drop in the controlled circuit and the useless power dissipated by the current sensor. These shortcomings are minimized, but by complicating the circuit.

In the proposed device, a different method of controlling the current in the lamp circuit is used - a relay method that uses the hysteresis of an electromagnetic relay and the starting current pulse inherent in an incandescent lamp when it is turned on. This method allows you to reduce the voltage drop in the controlled circuit to a negligible value. Unlike the devices described earlier, it indicates three states of the lamps.

principled brake light controller circuit shown in fig. 1. The current sensor is a reed relay K1, the winding of which is connected in series to the circuit of signal lamps HL2, HL3. A controlled pulse generator with a period of about 0.5 s is assembled on the logic elements DD1.1, DD1.2. Element DD1.3 is an electronic switch that operates with a time delay. Transistor VT1 is a current amplifier loaded with LED HL1.

When the brake pedal is not pressed and the SF1 contacts associated with it are open, only the pulse generator works. The lower input of the DD1.3 element according to the diagram is connected to a common wire through resistors R4, R5. Therefore, pulses do not pass through this element and its output is high. The low level at the output of the inverter DD1.4 closes the transistor VT1 - LED HL1 is off.

When you press the brake pedal, it closes the contacts SF1 and the current from the on-board network begins to flow through the fuse FU1 of the car, the winding K1 and the lamps HL2, HL3. If at the same time both lamps are working, then their starting current, although brief, but almost ten times greater than the nominal one, leads to reliable operation of relay K1.

The contacts K1.1 of the reed switch close, the supply voltage from the resistive divider R1R2 through the diode VD1 is supplied to the combined inputs of the DD1.1 element and blocks the operation of the generator, and a high level is fixed at the output of the DD1.2 element. The values ​​of the resistors R1, R2 are chosen in such a way that, at a relatively small current through the reed switch, the voltage taken from the divider corresponds to a unit level.

After a short period of time, the current in the lamp circuit will decrease to the nominal value, but the reed switch K1.1 remains closed, since the rated current of the two lamps HL2 and HL3 is greater than the release current of relay K1.

After the time Τ=R4-C2 (about a second) from the moment the brake pedal is pressed, the voltage across the capacitor C2 increases to the switching threshold of the element DD1.3. A low level appears at the output of the element, and a high level appears at the output of the inverter DD1.4, opening the transistor VT1. The LED turns on, indicating the health of the lamps.

After releasing the pedal, the lamps HL2, HL3 go out, the winding K1 is de-energized and the reed switch opens, allowing the generator to work. Its pulses periodically close the transistor VT1, so the LED blinks.

Capacitor C2 is discharged through resistor R4, relay winding K1 and lamps HL2, HL3, and after a while, when the voltage across it decreases to the switching threshold of element DD1.3, the pulses will stop passing to the input of the inverter. The transistor will not open, the LED will turn off. This display mode allows you to make sure that the lamps are working and at the same time that the generator is working.

If, when you press the brake pedal, one lamp turned out to be faulty (the contact in the cartridge burned out or the contact was broken), then the relay will first work under the action of the starting current of the second - serviceable - lamp. But the rated current of one lamp is not enough to keep the reed switch closed, and it opens. This process lasts several tens of milliseconds and does not affect the display in any way. After a second, the DD1.3 element will start to pass pulses from the generator and the LED will start flashing. When the brake pedal is released, the process is similar to that discussed above.

In the event that both lamps fail one after another or their power circuit is broken, the reed switch will not close at all and the LED will flash, as with one faulty lamp.

It happens that the FU1 fuse blows (or its contacts are oxidized). Then the supply voltage is not supplied to the device and when you press the brake pedal, the indication is completely absent.

Of course, an incandescent lamp can also be used as an indicator, but the reliability of the LED is higher.

The controller uses resistors S2-ZZN, OMLT; capacitors - ceramic, KM-5, KM-6, and oxide - K50-35. Instead of K561LA7, the KR1561LA7 chip is suitable. We can replace the KT315G transistor with any silicon n-p-p transistor, for example, KT501G-KT501E.

Reed switch - KEM-1; its winding contains nine turns of copper winding wire PEV-2 0.8. If a smaller reed switch is used, then the number of turns must be reduced, approximately 1.5 ... 2 times.

The socket of the X1 connector is RGN-1-3, and the insert is RSh2N-1-17. When replacing a connector with another, it is necessary to take into account the conditions of its operation - vibration and shock, high humidity and temperature. X2 and XZ connectors, designed for high current, are used for automobiles; it is permissible to replace them with screw terminals.

It is better to replace the AL307M LED with a brighter L-53SRC-E from Kingbright.

Structurally, the device is assembled on a circuit board with wiring MGTF wire with a cross section of 0.07 mm 2 and placed in a suitable insulating box. Connector block X1 is fixed in its end part.

For the manufacture of the relay, a tube is selected or glued from thick paper so that the reed switch can easily enter it. Rigid tubes are also suitable from any other non-magnetic material - metal or plastic. A winding is wound around the tube so that the axial length of the winding is somewhat less than the length of the reed switch bulb, and coated with epoxy glue. The conclusions are shortened to 8 ... 10 mm and serviced for mounting on the board.

The conductors connecting the relay winding to the vehicle's electrical system must have a cross section that is not less (or better, a little more) than that of the wires to the lamps. The controller should be placed as close as possible to the SF1 contacts and securely fastened. The LED is mounted on the dashboard.

When adjusting the controller connected to the car, the necessary sensitivity of the relay is selected by moving the reed switch relative to the winding. The reed switch in the optimal position is fixed in the tube with drops of glue.

On fig. 2 presented controller circuit for low and high beam lamps. Here, on the Schmitt trigger DD1.1, a clock pulse generator with a repetition period of about 0.5 s is assembled, on the trigger DD1.2 - a buffer inverter, on triggers DD1.3, DD1.4 - electronic switches with a time delay, similar to those used in the previous device, for high and low beam channels, respectively. Transistors VT1, VT2 serve as current amplifiers, their load is a two-color LED HL1. Current sensors K1 and K2 are the same reed relays. The generator operates continuously, regardless of the state of the reed switches K1.1 and K2.1.

Since both channels are the same, we will consider the operation of only the low beam channel. From the pulse generator, the clock sequence through the inverter DD1.2 is supplied to the upper input of the trigger DD1.4 according to the scheme. Since the lower trigger input is connected to the housing through the relay winding K1, fuses FU1, FU2 and dipped beam lamps EL1, EL2 (as well as through resistors R5, R8), its output is high. Transistor VT2 and LED HL1 are off.

When the lamps EL1, EL2 are in good condition, turning on the dipped beam leads to the appearance of voltage at the X2 connector, as a result of which they turn on. From their starting current, the relay K1 is activated, and through the reed switch K1.1, the voltage is supplied to the upper input of the Schmitt trigger DD1.4, but the trigger does not change its state. After establishing the rated current through the lamps, the reed switch remains closed.

After about a second, the voltage on the capacitor C3, increasing, reaches a high level at the input of the trigger, it switches to the zero state. Transistor VT2 opens and turns on the "green" LED assembly HL1.

When the dipped beam is turned off, the supply voltage at connector X2 disappears, the lamps turn off, the relay opens the reed switch K1.1. Pulses from the generator periodically switch the trigger DD1.4, which causes the LED to flash green. After some time, the capacitor C3 will be discharged and the Schmitt trigger DD1.3 will again block the passage of pulses from the generator to the base of the transistor VT2.

If at least one lamp (or its fuse) burns out, turning on the low beam will cause a green signal to flash after a second, indicating to the driver that a malfunction has occurred. This controller cannot accurately indicate the reason for the absence of the glow of the lamp.

The second channel - high beam - works similarly, only the "red" LED of the HL1 assembly serves as an indicator.

Instead of KT209G, any transistor from the KT503 series can be used in the device. It is advisable to replace the ALS331A LED with an analogue of increased brightness, for example, L-59EGC from Kingbright. With the KR1561TL1 chip, which allows a higher supply voltage, the controller will work more reliably.

Relays K1 and K2 use the same KEM-1 reed switches. The relay winding K1 contains 6 turns, and K2 has 2 turns, wound with PEV-2 wire with a diameter of at least 1.5 mm.

The circuit board of the device is placed in an insulating box of suitable dimensions, which is fixed near the high and low beam relay of the car. Relays K1 and K2 are connected to the electrical system with four flexible insulated wires with a cross section of at least 2 mm 2.

The operation of the described controllers on a VAZ-2106 car for several years has shown their reliability and ease of use.

LITERATURE
1. Chuikin A. Stop signal under reliable control. ≈ Behind the wheel, 1995, No. 9, p. 80.
2. Bannikov V., Varyushin A. Stop lamp controller. ≈ Radio, 1996, No. 8, p. 52.
3. Alekseev S. Monitoring the health of signal lamps. ≈ Radio, 1997, No. 5, p. 42, 43.

On front-wheel drive VAZ vehicles, a lamp health relay is used to monitor the status of the lamps for side lights and brake lights. Its function is to warn the driver, by means of a warning lamp on the instrument panel, of a circuit malfunction or lamp burnout.

The operation of the lamp health relay is based on the effect of a resistor bridge, the circuit diagram is shown in the picture. If the resistance of two parallel branches A-B-D and A-C-D is equal, then the potential difference between points B and C is zero. Accordingly, when the resistance of one of the arms of the bridge changes, a potential difference will appear between points B and C. A signal lamp is connected as one of the bridge resistances in the relay. Its burnout will lead to an unbalance of the bridge and a signal to the microcircuit to turn on the lamp health indicator lamp. To eliminate false relay operation due to a small run-up of the resistance of the filament of lamps from various manufacturers, the relay microcircuit is activated only at a certain potential difference close to the maximum, which is formed only when the lamps burn out. When replacing the marker lamps with LED lamps, it is necessary to modify the lamp health relay, that is, to balance the arms, since LED lamps have a higher resistance value, unlike incandescent lamps. To do this, it is necessary to replace the four resistances of the circuit of marker lamps, in the form of a wire spiral, with a resistance of 2.2 ohms and a power of at least 3 watts. It is better to make them yourself, as those that sell are large. The replacement of resistances is carried out only in those circuits where the lamps are changed. The front dimensions correspond to the resistances located between the legs 7-8 and 10-11, the rear ones, respectively, 1-7 and 9-10.
The lamp health relay can itself cause a malfunction in the parking light or brake light circuit. With an increase in current in the listed circuits, which can occur during a short circuit, using a high-power lamp (for example, from a headlight), etc., when the circuit is ringing, etc. In this case, the resistance in the lamp circuit burns out, the power of which is not designed for high current. At the same time, side lights or brake lights, in the circuit of which there is this resistance, will not burn. A defective relay must be replaced or repaired. If this is not possible, then you can short-circuit the corresponding relay outputs by connecting them together with a thin copper wire and insert the relay into place. In this case, the lamps will burn, but the relay will not work. It is necessary to connect the conclusions 1-7-8, 9-10-11 for the side lights to work and 4-5 for the brake light to work.

Technological control schemes consist of open channels, through which information about the course of the technological process enters the facility control point.

Technological control systems have a large number of parameters (or states of production mechanisms), about which only on-off information is sufficient for the normal conduct of the technological process (the parameter is normal - the parameter is out of the norm, the mechanism enabled - the mechanism is disabled, etc.).

These parameters are controlled by signaling circuits. Most often, in these circuits, electrical relay-contact elements with light and sound signaling of parameter deviations are most widely used.

Light signaling is carried out using various signal fittings. In this case, the light signal can be reproduced by a steady or flashing light, the glow of lamps in an incomplete channel. Sound signaling is usually carried out with the help of bells, beeps and sirens. In some cases, the signaling of the operation of protection or automation can be performed using special signal indicating relay-blinkers.

Alarm systems are developed specifically for this object, so there are always their schematic diagrams.

Schematic diagrams of signaling by purpose can be divided into the following groups:

1) position (state) signaling schemes - for information about the state of process equipment (“Open” - “Closed”, “Enabled” - “Disabled”, etc.),

2) process signaling schemes providing information on the state of process parameters such as temperature, pressure, flow, level, concentration, etc.,

3) command signaling schemes that make it possible to transmit various instructions (orders) from one control point to another using light or sound signals.

According to the principle of action, they distinguish:

1) signaling circuits with individual pickup of an audio signal, which are quite simple and have an individual key, button or other switching device for each signal, which allows you to turn off the audio signal.

Such schemes are used to signal the position or status of individual units and are of little use for mass process signaling, since in them, along with the sound signal, the light signal is usually turned off, too.

2) circuits with a central (common) pickup of an audio signal without repeating the action, equipped with a single device that can be used to turn off the audio signal while maintaining an individual light signal. The disadvantage of circuits without repeated action of the sound signal is the impossibility of obtaining a new sound signal before opening the contacts of the electrical devices that caused the appearance of the first signal,

3) circuits with a central pickup of a sound signal with repeat action, which compare favorably with previous circuits by the ability to repeatedly sound a sound signal when any alarm sensor is triggered, regardless of the state of all other sensors.

According to the type of current, circuits on direct and alternating current are distinguished.

In the practice of developing automation systems for technological processes, various signaling schemes are used, which differ both in structure and in the methods of constructing their individual nodes. The choice of the most rational principle for constructing an alarm circuit is determined by the specific conditions of its operation, as well as the technical requirements for lighting equipment and alarm sensors.

Position signaling circuits

These schemes are performed for mechanisms that have two or more working positions. It is not possible to show and analyze all the signaling schemes encountered in practice, as well as to analyze the reliability and effectiveness of each because of their diversity. Therefore, the most characteristic and frequently repeated variants of schemes in practice will be considered below.

The most widespread are two options for constructing signaling circuits for the position (state) of technological mechanisms:

1) signaling schemes combined with control schemes,

2) signaling schemes with independent power control schemes for a group of technological mechanisms of the same or different purposes.

Signaling schemes combined with control schemes, as a rule, are performed when the boards and control panels do not have mnemonic diagrams, and the useful area of ​​the boards and consoles allows the use of signal fittings without limiting its size, which allows direct power supply from control circuits. The signaling of the position (state) of technological mechanisms in such circuits can be carried out by one or two light signals with the lamps burning evenly.

Schemes built with a single lamp signal, as a rule, the on state of the mechanism and are used in conditions where the course of the technological process and reliability allow such signaling.

It should be noted that such schemes do not provide for equipment that allows periodically checking the serviceability of the lamps during operation. The lack of such control in the event of a lamp burnout can lead to false information about the state of the mechanism and disruption of the normal course of the technological process. Therefore, if the appearance of false information about the state of the technological process is not allowed, schemes with a two-lamp signaling are used.

Position signaling schemes using two lamps are also used for mechanisms such as shut-off elements (gate valves, dampers, valves, gate valves, etc.), as it is necessary to provide reliable signaling of two operating positions ("Open" - "Closed") of such devices with a single lamp is almost difficult.

Rice. one . Examples of building the simplest signaling circuits combined with control circuits

Rice. 2. Examples of signaling circuits with independent power supply: a - turning on the lamps through the auxiliary contacts of magnetic starters, b - bringing the circuit to a form convenient for reading, c - if the position of the control key does not correspond to the position of the controlled mechanism, the lamp flashes, d - if the control key does not correspond to the position of the controlled mechanism, the lamp burns with partial glow, LO - signal lamp "Mechanism is disabled", LV, L1 - L4 - signal lamps "Mechanism is on", V, OB, OO, O - positions of the control key of the KU (respectively "Enabled", "Turn on operation" , "Operation disable", "Disabled"), ShMS - flashing light bus, ShRS - even light bus, DC1, DC2 - additional resistors, PM - auxiliary contacts of the magnetic starter, KPL - button for checking lamps, D1-D4 - separating diodes

Let's sum up some results. Circuits with power control independent of circuits (see Fig. 2) are used mainly to signal the position of various technological mechanisms in mnemonic diagrams. In such circuits, small-sized signal fittings are mainly used, designed for AC or DC power supply with a voltage not exceeding 60 V.

The signal can be reproduced using one or two lamps burning with a steady or flashing light (see Fig. 2, c) or with an incomplete glow (see Fig. 2, d). Such light signals are usually used in circuits in which it is signaled that the position of the remote control of the mechanism, in this case the control key, does not correspond to the actual position of the mechanism.

In position signaling circuits with power control independent of circuits, performed using a single lamp, as a rule, equipment is provided for monitoring the serviceability of signal lamps (see Fig. 2, a).

Process signaling schemes

Process signaling schemes are designed to notify service personnel about a violation of the normal course of the process. Technological signaling is reproduced by a steady and flashing light and is usually accompanied by an audible signal.

The signaling by appointment can be warning and emergency. Such separation provides a different reaction of the operating personnel to the nature of the signal that determines one or another degree of violation of the technological process.

Process signaling schemes with a central pickup of an audio signal have found the greatest application. They make it possible to receive a new sound signal before opening the contacts that caused the previous signal to appear. The use of various relay and signal equipment, different voltages and types of current practically does not change the principle of operation of the circuits.

Technological processes require positional control of a large number of parameters, and a characteristic feature of process signaling circuits is the presence of common circuit nodes in which information from many on-off process sensors is processed.

Information from these nodes is issued in the form of sound and light signals only about those parameters, the values ​​of which are out of the norm or are necessary to control the technological process. Thanks to common nodes, the need for equipment and the cost of automating production are reduced.

Depending on the number of parameters to be signaled, the light signaling can be performed with a steady or flashing light. When signaling many parameters (more than 30), schemes with a flashing signal are used. If the number of parameters is less than 30, schemes with even light are used.

The algorithm of operation of process signaling circuits in most cases is the same: when a parameter deviates from a set value or an over-permissible value, sound and light signals are given, the sound signal is removed by the sound signal removal button, the light signal disappears when the deviation of the parameter from the permissible value decreases.

Rice. 3 . Technological signaling circuit with separating diodes and flashing light: LKN - voltage control lamp, Zv - bell, RPS - warning alarm relay, RP1-RPn - intermediate relays of individual signals, switched on by the contacts of sensors D1 - Dn of technological control, LS1 - LSn - individual lamps , 1D1-1Dn, 2D1-2Dn - decoupling diodes, KOS - signal testing button, KSS - signal pickup button, ShRS - even light bus, ShMS - flashing light bus

Rice. 4. Signaling scheme using a pulse pair instead of a flashing light source

Process alarm circuits with a dependent sound signal from a light signal are used only for warning signaling of the status of irrelevant process parameters, since in these circuits a loss of signal is possible if the signal lamp is faulty.

There may be technological signaling circuits with individual sound signal pickup. Schemes are built using for each signal an independent key, button or other switching device that turns off the sound signal, and is used to signal the status of individual units. Simultaneously with the sound signal, the light is turned off.

Command Signaling Schemes

Command signaling provides one-way or two-way transmission of various command signals in conditions where the use of other types of communication is technically impractical, and in some cases difficult or impossible. Command signaling diagrams are simple and generally easy to read.

Rice. 5. An example of a circuit diagram of command signaling (a) and an interaction diagram (b and c).

On fig. 5, a is a diagram of a one-way light and sound alarm for calling adjustment personnel to their workplaces. The call is made from the workplace by pressing the call buttons (KV1-KVZ), which on the dispatcher's board turn on light (L1-LZ) and sound (Sv) signals. The dispatcher, having set the number of the workplace from which the signal was received by the light signal, by pressing the button for picking up the KSS signal, brings the circuit to its original state. Relays RP1-RPZ and RS1-RSZ are intermediate.

Technological control schemes consist of open channels, through which information about the course of the technological process enters the facility control point.

Technological control systems have a huge number of characteristics (or states of production devices), about which, for the normal conduct of the technological process, the operator needs only on-off information (the parameter is normal - the parameter is out of the norm, the mechanism enabled - the mechanism is disabled, etc.).

The control of these characteristics is carried out using signaling circuits. In most cases, in these circuits, electronic relay-contact elements with light and sound signaling of deviations in characteristics are more widely used.

Light signaling is carried out using various signal fittings. With all this, the light signal can be reproduced by an even or flashing light, the glow of lamps in an incomplete channel. Sound signaling is usually carried out with the help of bells, beeps and sirens. In some cases, the signaling of the operation of protection or automation can be performed using special signal indicating relay-blinkers.

Alarm systems are developed directly for a given object, therefore their schematic diagrams are always available.

Schematic diagrams of signaling according to their intended purpose can be divided into the following groups:

1) position (state) signaling schemes - for information about the state of process equipment (“Open” - “Closed”, “Enabled” - “Disabled”, etc.),

2) process signaling schemes that provide information about the status of such process characteristics as temperature, pressure, flow, level, concentration, etc.,

3) command signaling schemes that make it possible to transmit various instructions (orders) from one control point to another using light or sound signals.

According to the principle of action, they distinguish:

1) signaling circuits with personal removal of the sound signal, which are quite simple and have a private key, button or other switching device for each signal, which allows you to turn off the sound signal.

Such schemes are used to signal the position or state of individual units and are not sufficiently applicable for mass technological signaling, because in them, immediately with the sound signal, the light signal is usually turned off,

2) circuits with a central (general) pickup of a sound signal without repeating the act, equipped with a single device with which you can turn off the sound signal, while maintaining a personal light signal. The disadvantage of circuits without repeated action of the sound signal is the impossibility of obtaining a new sound signal before opening the contacts of the electronic devices that caused the first signal to appear,

3) schemes with a central pickup of an audio signal with repetition of an action, profitably differing from previous schemes by the ability to repeatedly give an audio signal when any alarm sensor is triggered, regardless of the state of all other sensors.

According to the type of current, circuits on constant and alternating current are distinguished.

In the practice of developing automation systems for technological processes, different signaling schemes are used, which differ both in structure and in the methods of constructing their individual nodes. The choice of a more optimal principle for constructing an alarm circuit is determined by certain criteria for its operation, as well as the technical requirements for lighting equipment and alarm sensors.

Position signaling circuits

These schemes are made for devices that have two or more operating positions. To show and analyze all the signaling schemes encountered in practice, and to analyze the reliability and effectiveness of each because of their abundance is not likely. Therefore, further consideration will be given to more appropriate and often repeated in practice variants of schemes.

The most widespread are two options for constructing signaling circuits for the position (state) of technological devices:

1) signaling schemes combined with control schemes,

2) signaling circuits with independent power management circuits for a group of technological devices of the 1st or various purposes.

Signaling circuits combined with control circuits are usually made in this case when the panels and control panels do not have mnemonic diagrams, and the required area of ​​\u200b\u200bboards and panels allows the use of signal fittings without limiting its size, which allows direct power supply from control circuits. The signaling of the position (state) of technological devices in such circuits can be carried out by one or 2 light signals with the lamps burning with a steady light.

Schemes built with a single lamp usually indicate the on state of the mechanism and are used in conditions where the process and reliability allow such signaling.

It must be emphasized that such schemes do not provide for equipment that allows, during use, from time to time to inspect the serviceability of the lamps. The lack of such control in the event of a lamp burnout can lead to incorrect information about the state of the mechanism and disruption of the normal course of the technological process. Therefore, if the occurrence of incorrect information about the state of the technological process is not allowed, circuits with a two-lamp signaling are used.

Position signaling circuits with the introduction of 2 lamps are also used for devices such as shut-off elements (gate valves, dampers, valves, gate valves, etc.), because to provide reliable signaling of 2 operating positions (“Open” - “Closed ”) of such devices with a single lamp is actually difficult.

Rice. 1

Rice. 2 a - turning on the lamps through the auxiliary contacts of magnetic starters, b - bringing the circuit to a form that is comfortable for reading, c - if the position of the control key does not correspond to the position of the controlled mechanism, the lamp flashes, d - if the control key does not correspond to the position of the controlled mechanism, the lamp glows with incomplete heat, LO - signal lamp "Mechanism is off", LV, L1 - L4 - signal lamps "Mechanism is on", V, OB, OO, O - positions of the control key KU (respectively "On", "Operation enable", "Operation disable", "Disabled"), ShMS - flashing light bus, ShRS - even light bus, DC1, DC2 - additional resistors, PM - magnetic starter auxiliary contacts, KPL - button for checking lamps, D1 - D4 - separating diodes

Let's sum up some results. Schemes with independent power control schemes (see Fig. 2) are mainly used to signal the position of various technological devices on mnemonic diagrams. In such circuits, compact signal fittings are used to a greater extent, designed to be powered by alternating or constant current with a voltage not exceeding 60 V.

The signal can be reproduced using one or two lamps, glowing with an even or flashing light (see Fig. 2, c) or with incomplete heat (see Fig. 2, d). Such light signals are usually used in circuits that signal a discrepancy between the position of the mechanism remote control, in this case the KU control key, and the actual position of the mechanism.

In position signaling circuits with power control independent of circuits, performed using a single lamp, equipment is usually provided for monitoring the health of the signal lamps (see Fig. 2, a).

Process signaling schemes

Process alarm schemes are designed to notify maintenance personnel of a violation of the normal course of the process. Technological signaling is reproduced by a steady and flashing light and is usually accompanied by an audible signal.

The signaling according to its intended purpose can be warning and emergency. Such a division provides a different reaction of the operating personnel to the nature of the signal, which determines one or another degree of violation of the technological process.

The greatest application was found by technological signaling circuits with a central pickup of an audio signal. They make it possible to receive a new sound signal before opening the contacts that caused the previous signal to appear. The introduction of various relay and signal equipment, various voltages and types of current does not actually change the principle of operation of the circuits.

Technological processes require positional control of a huge number of characteristics, and a corresponding feature of process signaling circuits is the presence of common circuit nodes in which information from many on-off process sensors is processed.

Information from these nodes is issued in the form of sound and light signals only about those parameters whose values ​​are out of the norm or are needed to control the technological process. Thanks to common nodes, the need for equipment and the cost of automating production are reduced.

Depending on the number of characteristics to be signaled, the light signaling can be performed with a steady or flashing light. When signaling many characteristics (more than 30), schemes with flickering of the incoming signal are used. If the number of characteristics is less than 30, use schemes with even light.

The method of operation of technological signaling circuits is almost always similar: when a parameter deviates from a given value or an over-permissible value, sound and light signals are given, the sound signal is removed by the sound signal removal button, the light signal disappears when the parameter deviates from the permissible value.

Rice. 3 . Technological signaling circuit with separating diodes and flashing light: LKN - voltage control lamp, Zv - bell, RPS - warning alarm relay, RP1-RPn - intermediate relays of personal signals, switched on by contacts of sensors D1 - Dn of technological control, LS1 - LSn - personal lamps , 1D1-1Dn, 2D1-2Dn - decoupling diodes, KOS - signal testing button, KSS - signal pickup button, ShRS - even light bus, ShMS - flashing light bus

Rice. 4. Signaling scheme with the introduction of a pulse pair instead of a flashing light source

Process alarm circuits with an audible signal dependent on light are used only for warning signaling of the status of irrelevant process characteristics, because in these circuits the signal is likely to be lost if the signal lamp is defective.

There may be technological signaling schemes with personal sound signal pickup. Schemes are built with the introduction for each signal of an independent key, button or other switching device that turns off the sound signal, and is used to signal the status of individual units. Immediately with the sound signal, the light is turned off.

Command Signaling Schemes

Command signaling provides one-way or two-way transmission of various command signals in conditions where the introduction of other types of communication at the technical level is impractical, and in some cases difficult or unrealistic. Command signaling schemes are ordinary and usually do not cause difficulties in reading them.

Rice. 5. An example of a principle electronic circuit of command signaling (a) and an interaction diagram (b and c).

On fig. 5, and shows a diagram of a one-sided light and sound alarm for calling adjustment personnel to their workplaces. The call is made from the workplace by pressing the call buttons (KV1-KVZ), which on the dispatcher's board turn on light (L1-LZ) and sound (Sv) signals. The dispatcher, having set the number of the workplace from which the signal was received by the light signal, by pressing the button for picking up the KSS signal, brings the circuit to its initial state. Relays RP1-RPZ and RS1-RSZ are intermediate.

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