led lighting knowledge
LED projector lighting called spotlight, projection lamps, spotlights, etc., mainly used for decoration lighting use, and commercial space lighting, decorative elements heavier, its shape is also a well-rounded because the general had to consider the reasons for cooling and therefore its shape with the traditional projection lamp, there are some differences.
LED projector lighting features:
Commonly used in currently available LED projector lamps for light use is basically a high-power 1W LED (each LED component made with a PMMA lens with high light efficiency, and its main function is the LED light from the secondary distribution, that is, two order optical), there are few companies with the cooling techniques are handled well, or even choose to use a higher power 3W LED. suited for large occasions, cast lighting, building lighting.
choose led flood lights
Spotlights there any need to pay attention to things?
1, high purity aluminum reflector, beam the most accurate reflection the best results.
2, symmetric narrow-angle, wide angle and optical systems with non-symmetry.
3, behind the open? Type lamp replacement, maintenance is simple.
4, lamps are easy to adjust the exposure with the angle scale plate.
LED projector lamps for light control through the built-in microchip, in a small engineering applications, you can not control use, to achieve a gradual, transition, color blinking, random blinking, alternating gradient and other dynamic effects, but also can control DMX achieve chase, scan results. Currently, its main application areas are about these: single building,? Historical buildings exterior lighting, building lighting, optical transparency, the local interior lighting, green landscape lighting, billboard, medical facilities, cultural and other special lighting, bars, discos and other entertainment atmosphere, lighting and so on.
what is the LED flood light?
LED floodlight is a uniform exposure to the light source in all directions, its illuminated area can be adjusted, in the scene appears as a regular octahedron of the icon. Floodlight is, in effect, making them the most widely used figure of a light source, standard floodlights used to illuminate the entire scene. Scenario can be applied to many light floodlights, to produce good results. Floodlight is, in effect, the most widely used figure of a light source, the scene can use more light floodlight coordinating role, to the birth of good results. From a specific point in all directions uniformly irradiated object, use it to simulate the light bulbs and candles better and better. Floodlights can be placed anywhere in the scene.For example, the camera can be placed outside or inside of objects. Distance in the scene with many different? Color of the floodlights is very common. The floodlights can be mixed in the dark and the model projection. Floodlights illuminated area of the relatively large, so the floodlights of the radiation effect is very easy to predict, and this light there are many secondary uses, for example, floodlights placed in the position near the surface will be in the Surface to generate bright light.
It should be noted that the floodlights can not build too much, otherwise the rendering will be very flat and expressionless. So in effect drawing the usual production, more attention to lighting parameters and experience? Bureau of rendering the entire scene a sense of the impact of light, more accumulation of experience, master the skills mix of the light.
Flood light features:
Flood light from a specific point in all directions uniformly irradiated object, use it to simulate the light bulbs and candles better and better. Floodlights can be placed anywhere in the scene.
LED lighting in the landscape lighting has gone through ten years of history, and its control technology has developed in several stages, each stage to solve the many problems at the same time raises new questions each point. The following LED control technology to further discussion.
1, LED display driver control over the way the transfer mode. Using the 74HC595, DM115, MBI5026 chip serial shift, and similar communication method, each chip cascade, the cascade of each lamp. Both of which also have constant current constant voltage drive drive. The means of communication leads to the question is too much light on the signal line, to 4 or 5 (including the ground), not only to increase the company’s production and commissioning of the time cost and material cost, the project also increased the time cost of installation and material costs , which leads to the increase in failure rate, the biggest problem is the front end of a string of lamps or signal damage to the chip, the back-end is also affected. The advantage is of course not be denied, HC595 cheap, chips mature, light and easy to program design, market, multi-controller support.
2, DMX512 protocol RS485 bus form, plus the chip microcontroller using RS485 (MCU) in the way of forming a bus hang 512 points RS485 effective parallel system, each lamp to do with the address number to each receiving different data, to adjust The purpose of light color. The relatively one way, reducing the root of the number of signal lines, and basic elimination of the lighting of a lamp failure of the phenomenon of follow-up, the signal transmission distance is relatively far distance between the lamp and the light from a few meters, tens of meters of the restrictions. However, this approach also brings other negative issues, first, the high cost of DMX decoder, a little higher than when purchased, own and needs good engineers, and number of each lamp was not addressed and the need to increase number automatically signal line, there is sometimes a problem of bus decoder to find difficult problems, then there is a limited number of each host controller with lights to increase the overall system hardware cost. Impact of these negative issues are also a large number of DMX512 system, the use of reason, can only be used in some high-end projects.
3, in-line communication, 3 port, 6 port drive the proliferation of chip LED lamp design makes it easier. Single chip representatives ZQ1111, TLS3001, TM1803, SDMX5124 such, they are between the chip and the chip with the signal line through the single serial cascade, the chip I / O PWM output can be automatically scanned, so the signal line The communication speed can be greatly reduced, the distance between the chip and the chip is less than 2 Mi Neiji This eliminates the need for the HC245. Such chips to meet both the high gray (256 level) data transmission, but also increase the number of series lights. Current light source and the light string (section) has been widely used, guardrail section because of the need to use more chips, and a chip using mature and stable, and gradually replace also need a process. Advantage of the phase of the innovation is obvious, for the point light source and the light string (section) is only designed three output ports, internal with PWM output, the data transmission efficiency is greatly improved data transfer speed greatly reduced, thereby improving reliability, Province to the amplification components, an increase of the number of cascade, lighting greatly improved design flexibility. However, the fly in the ointment is there, first of all, most chips are just listed soon, there on behalf of the consideration of stability and improvement of stability of prices and slightly expensive side, single lamp requires the application of multi-chip limited. Secondly, transmission of data or the use of cascading, or signal failure of front-end chip, the chip and the signal back, once again, the controller on the market is not a lot of support, customer choice is limited.
4, DC-carrier modulation communication applications for LED lighting control system. DC-DC power carrier line by definition is loaded in the waveform, the transmitted signal, to power, signal transmission lines with the purpose of the lamp so no need to use the system signal line, only the power cord. Under which to describe the signal line on the lighting system without the advantages of: 1. To reduce the factory when the welding process lights, the time cost of connecting signal lines and signal lines of the material costs, 2. To reduce light engineering connections, the time the signal line layout cost and signal line material costs, 3. improve the lighting system of commissioning, maintenance, speed, single lamp is broken does not affect other lamps, failure to determine visually, which look bad light which lights. The basic principle is the carrier power modulator switching power supply input connection, the signal input connector LED master controller output, the output of a band carrier signal after the power lines, each parallel to this set of lights on the power line within each light and then the power line carrier demodulator signal demodulated by the microcontroller (MCU) after controlling lighting, back to using a dedicated integrated chip demodulator after filtering the power supply to the lamp voltage for the rectifier electricity. Therefore, each switching power supply with a carrier modulator, lamps do not need to signal line. Carrier’s wide range of current rates can be chosen at random from 0-1MHZ the modem can be designed to be compatible with DMX512 DMX512 protocol agreement or forward signal, the main market of the DMX512 controller can be used, greatly expanding customer choice. DC carrier also has its drawbacks exist, 1. Because of the power line loads the signal, resulting in larger power line impedance, line voltage drop becomes larger, so the need to improve power supply input voltage a few volts in order to meet the back-end full-power lighting load voltage requirements, 2. for a Bus line, lamps need to write the address number to distinguish the signal data location, 3. due to carrier modulation and demodulation devices exist, so the total cost of the system will not be cheaper than the 1,3-system, but below the second phase of the DMX512 system.
Here, more than 4 points on the performance and price comparisons, the price, the first is between 1 and 4 (3) and 2, and in performance, then 4 points is the most superior. When is the most cost-effective DC-carrier communication system.
DMX512 protocol is the first USITT (United States Theatre Technology Association) to become the standard digital interface from the console control dimmer way. DMX512 beyond the simulation system, but can not completely replace the analog system. DMX512 simplicity, reliability (if correctly installed and used it!), And the flexibility to quickly become the choice of funds under the agreement allows, in addition to the dimmer, the range of control equipment is growing evidence. DMX512 is still a new field of science, based on the rule has generated all kinds of wonderful technology. EIA485 (RS485) DMX512 is built around industry standard EIA485 interface design. EIA485 are interfaces, voltage, current, etc. “electric” side. System is based on the downward along the shielded twisted pair conductor established symmetric transmission. This spiral structure to ensure that the interference generated by the same act on the two signals, thus ensuring a consistent number of phase. Wire should be used by one or two twisted pair, foil and braid screen composed of the appropriate data cable. Audio cable symmetry can not finish the job. Normally, the same as any network segment, the wire ends should have two terminals. As usually in a lighting console terminal, and the other end should be only one 120Ω resistor. EIA485 specification only support the “daisy chain” or up to a maximum of 32 on each “unit load” posed by the serial network. Each manufacturer can claim up to 1000m. However, to highlight that the role of repeaters should be considered about 700m or 800m, which can prevent abnormal environment. XLR connector pins as follows: needle shield to the signal 1 / 0 V 2 internal conductor (black) data – 3 internal conductor (white) data + 4 internal conductors (green) secondary data – 5 internal conductor (red) secondary data + DMX512 control cable with 5 pin XLR (sometimes 3-pin) to connect devices (Table 1); parent interface for the transmitter, and the public interface for the receiver specification recommended a two pairs of wires (4 connector ) to achieve shielding, although only need one pair. Second pair of wires for the optional unspecified occasions. Should be noted that some of the dimmer use of these lines to indicate the fault and status information. Used if Dimmer second channel, you need specially configured splitter and repeater. The cable to the logic level of the safest method is to use a “standard” interface IC-TexasInstruments the SN75176B, if you want to achieve connectivity and isolation, Burr-Brown’s ISO485P is a good choice. Method of using these interfaces to provide a rating for each device unit load, these devices allow you to install up to 32 segments receiver. Across the line is not recommended to connect through a direct high-sensitivity direct-line optical isolator interface mode, it provides load than normal load on the receiver is 5 times, thereby reducing the segment can be installed on the receivers. In addition also cause distortion, increasing the risk of errors and lead to meet the EIA485 receiver fails, these are bad news! Data is based on an 8-bit data to send asynchronous serial protocol, with a start bit (low) and two stop bits (high), no parity. Thus, a data frame with 11 bits. Since the width of each is 4 Uu, it needs to send a frame 44 Uu time. If the line you want to send a continuous stream of data, it will produce 250000b / s data rate, or 250k baud. 8-bit word for each dimmer allows the range of 0 to 255 to send 256 separate levels. Start and stop bits for the transmitter and receiver synchronization. Data lines are usually at a high level; in fact it is high when idle state (more often in this state.) The emergence of the start bit to work to promote the receiver, behind the 8-bit data to be scanned and decoded (hopefully). Then the receiver waits the arrival of stop bits, stop bits will be again after this process. We need to stop bit for two reasons: so that the receiver has sufficient time to process the input data; to the state line is high, so the next “start” can be detected. Figure 1 depicts a frame inside the bit level, this frame contains the data “0” and “255.” So far has been very clearly explained, but not yet finished, DMX512 can support up to 512 dimmers, and now we have only seen the first one, then how to deal with all dimmers information? The answer is simple, just repeat the process! Yes, it is that simple. But now the situation is not so simple, we made the segment a data stream, but there is no way to identify which frames belong to which the dimmer. See “DMX Pack” section of the prompt. DMX512 “package” DMX512 package is the core of this standard, which consists of a deep set of synchronization information frame structure, in which the depth information is a “Break” and a “Mark-after-break”. That this information will enable the receiver to detect the start of a frame, it can handle the received data. Frame timing test shows the longest line at a low level of 4 Uu (start bit) +8 × 4 Uu (data bits) = 36 Uu, but a “Break” contains at least 88 Uu a “low”, which the difference can easily be detected, the dimmer can be used for synchronization. “Mark-after-break” on the line is “high” state, the width of at least 8 Uu time, “Mark-after-break” is necessary because in order to detect the “Break”, otherwise the frame will be followed by the start bit “Break”, the line has been caught in the low state. At this point will be very confusing! A description of “package” of Figure 2 helps to explain the above problem. “0” value indicates the back of the frame contains information on the dimmer level. 255 additional code is not defined in the specification, but some manufacturers have used the other code to send the product specific information. Non-zero start code of a receiver dimmer “will” ignore the rest of pack, but be careful, it will not always be checked to! Timing summarized as follows: Minimum Maximum Break 88μs 1 秒 Mark-after-break 8μs 1 Second Inter-frame-time 0μs 1 Second “Inter-frame-time” used to reduce data rate. Some dimmers can not handle high speed data, or other tasks at the same console used for “insert” the transmission. Its value can be from 0 to 1 seconds. Specification set some restrictions for the time. It can be seen from the above, the data rate is very scalable, but to note that the state does not allow continuous line in the “high” or “low” state than a second time, and error conditions should be considered at this time. DMX512 system in the almost all of misuse are lack of knowledge from the system. A place that is causing the problem in the signal separation. Remember, the end section of the system to run. Simply the Line separation (seems logical) volume due to the repeated changes in ohms and can not work. To do so easily lead to the destruction of the signal. Solution is to use the “splitter” and “repeaters” power equipment “listen” segment of the data, and then broadcast, or as needed in the next paragraph to “reproduce.”
Input anti-jamming performance switching power supply, because of the characteristics of its own circuit (Tandem), the general input disturbance, such as surge voltage is difficult to pass, the output voltage stability index of this technology compared with the linear power with more Big advantage, its output voltage up to (0.5 ~ 1)%. Switching power supply module as an integrated power electronic devices, in the selection should note the following:
The choice of output current
Due to high efficiency switching power supply, generally 80% or more, so in the choice of the output current should be accurately measured or calculated the maximum absorption current of electrical equipment to be used so that the switching power supply with high performance and low cost,usually
Output is calculated as:
Is = KIf
Where: Is-switching power supply rated output current;
If-electrical equipment, the maximum absorption current;
K-factor margin, generally of 1.5 to 1.8;
Switching power supply linear power supply will produce more than the interference, common mode interference on sensitive electrical equipment,grounding and shielding measures should be taken by ICE1000, EN61000, FCC and other EMC constraints, switching power supply electromagnetic compatibility EMC measures are taken,
Therefore, switching power supply should normally be with EMC EMC filter. Hua Fu techniques, such as HA Lead Series switching power supply, its FG terminals to chassis ground or take the user in order to meet the electromagnetic compatibility requirements.
In the design of switching power supply must have been current, overheating, short circuit protection, it should be the preferred protection in the design of switching power supply modules are available, and the technical parameters of its protection circuit with electrical equipment should match the operating characteristics,
To avoid damage to electrical equipment or switching power supply.