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ENCYCLOPEDIA OF RADIO ELECTRONICS AND ELECTRICAL ENGINEERING Two-channel controller of a light cord of the Duralight type. Encyclopedia of radio electronics and electrical engineering
Encyclopedia of radio electronics and electrical engineering / Lighting Abstract. Currently, for outdoor advertising, architectural lighting, lighting design of bridges, interior design and light illumination, light cords of the "duralight" type in various configurations are widely used. If such a light cord is supplemented with a simple digital controller, then certain light-dynamic effects of switching the light cord can be obtained. General information. "Duralight" is a flexible cord of round (rarely rectangular) section made of colored light-diffusing plastic (PVC), which is used to fill a garland of miniature light bulbs or LEDs. The light cord has high performance characteristics: water resistance, shock resistance (withstands weight up to 100 kg per 2,5 sq. cm), flexibility (rotation angle up to 60 degrees), low power consumption, can operate in a temperature range from -30 to + 60 degrees C; the glow resource is from 25000 (for lamp) to 100000 (for LED version) hours. According to the modification of the glow, the following series of lamp "duralight" are distinguished: 1. Fixing series - works in the mode of continuous glow of bulbs of the same color. It does not connect to the controller. The cord is painted in a certain color, inside are ordinary colorless incandescent bulbs. This series is supplied in two versions: mini and regular 2-wire duralight. Colors: blue, white, yellow, orange, red, green. 2. Chasing series - when connected via the controller, it works in the mode of light dynamics of one color. When connected to the network directly, it works as a fixing series. The cord is painted in a certain color, inside are ordinary colorless incandescent bulbs. This series is supplied as a 3-wire duralight. Colors: blue, white, yellow, orange, red, green. 3. Chameleon series - when connected via the controller, it works in two-color light dynamics mode. When connected to the network directly, it works in the constant glow mode of two colors at the same time. The cord is transparent, the bulbs of two colors alternate inside. This series is supplied as a 3-wire "duralight". Colors: red-yellow, yellow-green, red-green, red-blue, green-yellow. 4. Multichasing series - when connected via the controller, it works in the mode of four colors of light dynamics: red, green, blue, yellow. When connected to the network, it works directly in the constant glow mode of fragments of four colors (4 bulbs of the same color) at the same time. The cord is transparent, the bulbs of four colors alternate inside (four bulbs of each color). This series is supplied as a 5-wire "duralight". According to the listed series, the multiplicity of cutting and the power consumption of light cords change. For the fixing series, the cutting ratio is 1 m, for the chameleon and chasing series - 2 m, for the multichasing series - 4 m. The power consumption of "duralight" varies from 16,38 W/m (fixing, chasing, chameleon) to 21,6 W/m (multichasing). Usually, one end of the "duralight" segment is connected with a power cord using an adapter sleeve, which is connected directly to the 220 V network. A plastic plug is put on the other (free) end. Segments of "duralight" can be connected to each other with a male-male connector and fastened with a coupling or a special heat-shrinkable film. In the author's version, a two-channel controller is used to control a "duralight" light cord of the multichasing type, 12 m long. Red and blue, as well as green and yellow bulbs are grouped together into two channels, respectively. In this case, the maximum power consumption is about 260 W, i.e. 130 W for each channel. Unlike the designs of controllers available on the Internet, the proposed option has no limitation on the duration of the operation time. In this case, there is no need to press any buttons during operation to return the controller to its original state.
Principle of operation. The electrical circuit diagram of the controller is shown in fig. 1. The controller contains: two master generators on the elements DD1.1, DD1.2 and DD2.1, DD2.2, respectively; RS-trigger DD3.1, DD3.2 increasing-decreasing brightness; reversible counter DD4 formation of binary codes of brightness; decoder DD5 counter states DD4 and LED indication line HL1-HL16; inverting elements DD1.3…DD1.6 code combinations counter DD4; counter-shaper DD6 of the phase angle of the first channel, as well as RS-trigger DD8.1-DD8.2 for controlling switching elements (VT3, VS1); counter-shaper DD7 of the phase angle of the second channel, as well as RS-trigger DD8.3-DD8.4 for controlling switching elements (VT2, VS2); parametric stabilizer on the elements VD3, VD4 ... VD7, R14, R15, C5; powerful rectifier diode bridge VD8…VD11.
The rate of increase-decrease in the brightness of the garlands is set by a variable resistor R2, which is included in the time-setting circuit of the rectangular pulse generator DD1.1, DD1.2. The device uses the so-called phase-pulse method of controlling the opening moment of switching thyristors. At the beginning of each half-cycle of the mains voltage, the thyristors close. At the same time, the garlands are de-energized. From this moment, the countdown of the time interval begins until the opening of the thyristors. The longer this time interval, the lower the brightness in a certain channel, and, conversely, the shorter the time interval from the moment the mains voltage passes through zero to the moment the thyristor opens, the greater the brightness in this channel. This is explained by the time diagrams shown in Fig. 2. Gating pulses are formed at the beginning of each half-cycle at the moments when the mains voltage passes through zero (Fig. 2b). A small brightness of the garland corresponds to a long turn-on time (t on) of the thyristor (Fig. 2c), and vice versa, a high brightness corresponds to a small turn-on time (t on) of the thyristor (Fig. 2d). Consider the operation of the controller, counting from the moment the mains voltage passes through zero. Let us assume that at this initial moment of time the reversible counter DD4 operates in the summation mode, i.e. the binary code at its outputs 0…3 is increasing. When the mains voltage passes through zero, the transistor VT1 closes and a short negative pulse lasting several tens of microseconds is formed at the output of the DD2.3 element. Influencing the inputs preset "C" counters DD6 and DD7 this pulse produces a record of binary codes on the inputs of the counters D0 ... D3 in their own binary digits. At the same time, the RS-flip-flops DD8.1-DD8.2 and DD8.3-DD8.4 are reset to the initial zero state, which corresponds to the off state of the garlands in both channels. Thanks to inverters DD1.3 ... DD1.6, mutually inverse binary code combinations are loaded into counters DD6 and DD7. This determines the operation of the two channels in antiphase mode, i.e. while in one channel the brightness increases, in the other channel the brightness decreases. Since the reversible counter DD4 operates in the summation mode, as discussed above, in its own binary digits of the counter DD6 at each moment of the network voltage transition through zero, successively decreasing binary combinations are loaded. Consequently, the brightness in this channel decreases (garland EL1), and increases in the second channel (garland EL2). To count the time interval from the moment the mains voltage passes through zero until the moment one of the thyristors is turned on, rectangular pulses of the master oscillator are used on the elements DD2.1, DD2.2. As soon as the voltage at the output of the diode bridge VD8 ... VD11 slightly exceeds zero, the transistor VT1 opens and switches the element DD2.3 to a single state. A high logic level from the output of the element DD2.3 will open the element DD2.4 and allow the passage of pulses to the summation inputs of the counters DD6 and DD7. If the "maximum" binary combination "6" is written to the internal binary digits of the counter DD1111, then the first negative pulse at the addition input "+" (pin 5) will cause a negative pulse to appear at the transfer output "+CR" (pin 12) and setting RS flip-flop DD8.1-DD8.2 to a single state. This level will lead to the opening of the transistor VT3 and, after it, the thyristor VS1 and the ignition of the garland in the first channel (EL1). Thus, at the output of the RS-trigger DD8.1-DD8.2, a rectangular pulse of maximum duration will be generated, corresponding to the maximum brightness in the first channel. The brightness of the garland in the second channel (EL2) will be minimal, since the "minimum" binary combination "7" was loaded into the input binary digits of the counter DD0 (inputs D3 ... D0000), which corresponds to the maximum time interval, counting from the moment the mains voltage passes through zero to the moment of switching the RS-flip-flop DD8.3-DD8.4 to a single state. Thus, at the output of the RS-trigger DD8.3-DD8.4, a rectangular pulse of minimum duration will be generated, corresponding to the minimum brightness in the second channel. When the counter DD4 reaches the maximum state (at the outputs: "1111"), the combination "6" will be sent to the inputs of the counter DD0000, which will correspond to the minimum brightness in the first channel (EL1), and, accordingly, the maximum brightness in the second channel (EL2), since the inputs of the counter DD7 will receive the code combination "1111". The output code combination "1111" of the counter DD4 is decoded by DD5 and the low logic level from the output of its most significant bit "15" (pin 17) will switch the RS flip-flop DD3.1-DD3.2 to the opposite zero state. Now the logical unit level from the output of the element DD3.2 will open the element DD3.4 and allow the passage of pulses from the master oscillator DD1.1-DD1.2 to the subtractive input "-" (pin 4) of the reversible counter DD4. Now the mode of operation is defined as an increase in brightness in the first channel (EL1) and a decrease in brightness in the second channel (EL2). Further, the cycle of work is completely repeated.
Construction and details. The controller is assembled on a printed circuit board (Fig. 3) with dimensions of 120x95 mm from double-sided foil fiberglass 1,5 mm thick. The device uses resistors of the type MLT-0,125, MLT-2 (R14, R15), constant capacitors of the K10-17 type (C1, C2) and electrolytic capacitors of the K50-35 type (C3 ... C5); tuning resistor R4 - type SP3-38b in horizontal design, variable R2 can be any small; transistors VT1 ... VT3 of the KT3102BM type can be replaced with any of this series, as well as the KT503 series and other low-power npn structures; LEDs HL1…HL16 - red, 3 mm in diameter; zener diodes VD1 and VD3 can be any low-power ones with a stabilization voltage of 8 ... 12 V. SCRs can be from the KU201, KU202 series with the indices "K", "L", "M", "N". Powerful FR307 diodes are interchangeable with similar ones with an operating voltage of at least 400 V. All CMOS microcircuits of the KR1564 series are interchangeable with the corresponding analogues of the KR1554 series. A low-power parametric stabilizer is used to power the entire controller, and an integrated stabilizer of the KR142EN5A type is used to power the digital part. The use of a parametric stabilizer instead of a step-down transformer became possible due to the very low power consumption of the CMOS microcircuits of the KR1564 series. Most of the power is consumed by LEDs (about 6 mA) and thyristors at the moments of switching. In the author's version, the design is assembled in the form of a small house, and the LEDs are located at the miniature windows. Thus, the "running fire" of the LEDs creates the illusion of revival in the house. (The house itself was located under the New Year tree.) If desired, LEDs can be excluded from the design. The functionality of the circuit will not deteriorate, but the load on the parametric stabilizer will slightly decrease. Setting the controller is to set the frequency of the master oscillator DD2.1, DD2.2 trimming resistor R4 and select the desired rate of increase in brightness using a variable resistor R2. Before turning on for the first time, the slider of the resistor R4 is set to the middle position, and then by turning it, the range of changing the brightness of the garlands is completely covered. When the resistance of this resistor decreases, the frequency of the generator increases, therefore, the counters DD6 and DD7 will overflow ahead of time, and the brightness will also decrease to zero ahead of time. If the resistance R4 is excessively large, then the overflow signals of the counters will be delayed, and the brightness range will not overlap completely. The disadvantage of this device can be attributed to the relatively large discreteness of the change in brightness, the number of gradations (levels) which is equal to the conversion factor of the counters DD6, DD7. Transitions between levels become especially noticeable with a long period of increase-decrease in brightness. To make the overflows of brightness ideally smooth (to achieve low discreteness), it is necessary to turn on one more of the same counter in series with DD6 and DD7. In this case, it is possible to achieve a discreteness of brightness change equal to 256 levels. Naturally, in this case, it is necessary to increase the frequency of the master oscillator assembled on the elements DD2.1, DD2.2. With a light cord length of up to 12 m, there is no need to install thyristors and powerful diodes on radiators, since the average power per channel does not exceed 65 W. With a longer length of the light cord, the switching power will increase. Accordingly, thyristors must be installed on radiators, and diodes should be used in metal cases. They also need to be installed on radiators. Attention! The design has a direct galvanic connection with the AC mains! All elements are powered by 220 V. When setting up the device, you must use a screwdriver with a handle made of insulating material. The handle of the variable resistor R2 must also be made of insulating material. Author: Odinets A.L.
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