【Lighting performance in fountain system】
Author：太行噴泉Update Time：2025-01-20
The lights in the fountain
Since the 1980s, fountains have gradually been introduced to China and have made significant progress as a special artificial landscape. There are large lake fountains, sea fountains, square fountains, as well as small fountains in various places. There are also many miniature indoor fountains, which are diverse and varied. According to the classification of water types in performance forms, there are about 100 types of water types, such as stacked water, running spring, peacock opening screen, inner arch, etc., but these are not the focus of this article's discussion. Fountain systems are usually composed of the movement of water in the water system, and there are control methods such as music fountains and programmable fountains. On fountain equipment, it is composed of pipes, nozzles, water pumps, colored lights, control cabinets, cables, and sometimes computers, speakers, audio power amplifiers, etc. Some large fountains are also composed of lasers, computer lights, etc. So, colored lights are an important auxiliary component in fountain water performances, especially in outdoor night water performances. Colorful lights add more expressive power to fountain water performances. A performance without colored lights is like a stage without lights, pitch black.
The development of colored lights in fountain systems has gone through several different historical stages. 1) At the beginning of the development of fountains in China, due to the lack of a unified underwater lamp, the method of installing incandescent lamps in waterproof lamp housings was often used for treatment. 2) In the future, Phar38 lamps from Philip Company in the Netherlands were gradually introduced. Phar38 lamps comply with European standards and are domestically produced using 220V AC voltage drive. The bulbs are all white incandescent lamps. The lamp housing is made of glass and changes color by applying colored paint on the surface of the transparent glass. Generally, there are red, white, green, blue, yellow, etc., and when combined with a water type, it is usually a series or several parallel lights of the same color. Of course, light bulbs also use other light sources such as high-pressure sodium lamps, low-pressure sodium lamps, high-pressure mercury lamps, etc. These belong to high-pressure AC lamps, which have low luminous efficiency and high heat generation. Glass products are fragile, especially when used underwater. When glass products are heated and suddenly cooled by water, they often crack and shatter. 3) With the rise of LED point light sources, industry colleagues are working to solve the problem of using LED point light sources for fountain lighting. LED point light sources have high luminous efficiency, low heat generation, pure color, high color rendering index, long lifespan, and are energy-saving and environmentally friendly. However, early LED beads were expensive, and in order to reduce production costs and be compatible with existing high-voltage lamp systems, most of them used RC voltage division to directly drive LED bead strings by reducing voltage. LED chips emit light from semiconductor PN junctions and are sensitive to the forward voltage on the PN junction. Therefore, the RC voltage division method without a voltage stabilization system often burns out the entire string, and this lighting control method is not widely accepted by users. Moreover, due to the high pressure directly entering the pool and connecting easily damaged LED light equipment, it is also very unsafe for operators and maintenance personnel. 4) LED light is a product with great application prospects. Major manufacturers around the world are investing a lot of funds and technical strength in scientific research, continuously improving product quality, and the unit price of light beads has dropped sharply. So far, it has become an excellent solid-state point light source, with luminous efficiency far higher than ordinary incandescent lamps and cold cathode ray tube energy-saving lamps, and even higher than the high-frequency induction lamps currently being promoted abroad. The theoretical lifespan can reach up to 100000 hours, and in practical applications, under reasonable environmental conditions, it can basically reach 30000 to 50000 hours. Therefore, most fountain companies currently use low-voltage LED lights as underwater lights. Following the traditional method, LED underwater lights are connected in a string and directly controlled to turn on and off through an electrical control cabinet. Low voltage LED lights can be used as AC lights or DC lights, but regardless, they are still very safe to use at low voltage. If a high-power switching power supply or other DC power supply with voltage stabilization function is used, it can also effectively protect LED underwater lights. Due to the decrease in the price of LED chips, there is no doubt that this method will replace traditional high-voltage lamps. But this approach is only an advancement in lighting equipment and has not changed the way fountain lighting is performed. The lighting is still a traditional and lifeless transformation, and cannot have endless light changes like a real stage. 5) The rise of digital lights and the deepening development of digital control technology in fountain applications have led to the promotion and application of underwater fountain lights transformed with digital control technology.
Digital light
The difference between digital lights and traditional lights is the use of digital control technology to achieve lighting control. Some people also commonly refer to computer lights, such as the 8-channel or 18 channel computer lights commonly used on stage, which belong to the category of digital lights. The reason behind this is that various behaviors of digital lights can be controlled through digital communication methods, enriching the content of lighting performances. The simple way of changing colors by simply switching on and off different lights has been transformed into a lighting control method that can be controlled by a single light, make the lights move, and approximate stage performances. The introduction of this lighting performance form in fountains has revolutionized the traditional fountain lighting performance method. In summary, there are many characteristics in control: 1) Single lamp control can be performed, with each lamp serving as a control point that can be adjusted separately. 2) Capable of controllable color changes in lighting. Generally composed of three primary colors, it can change the color of the light, especially to achieve gradient control of various colors. 3) It is possible to adjust the brightness of the lighting. 4) It is possible to change the lighting angle and direction of the lamp, and the speed of the change can be freely controlled. These are also the basic requirements for most computer lights.
It should be emphasized that the fountain specific digital lights, which closely integrate computer light control technology with LED light manufacturing technology and fountain control technology, represent the future development direction in terms of both the cost and control methods of fountain applications. Firstly, it is an LED light for underwater applications with good waterproof performance. Secondly, it adopts a communication control method to control the brightness and color synthesis scheme of the three primary color LED light, which can meet various color change requirements. Furthermore, through fountain control technology, it can perform light performances in the music fountain according to the rhythm of the music, synchronously controlling with the water type performance, achieving the performance effect of stage lighting.
Application of Laser in Fountain Lighting
By the way, let me mention the issue of laser lighting in the fountain. Laser has been used in fountains for a long time. About a decade ago, when the quality of domestic civilian laser generators was not yet satisfactory, imported lasers were used in fountains. Due to cost reasons, they were only used in large music fountains. The laser first performs on the water screen, which is part of the music fountain. The laser show becomes the protagonist, and other water types become the supporting role of the laser show. The focus of this article is not on laser water curtain performances, but on the use of optical fibers for fountain lighting. The optical fibers specifically used for lighting will partially emit light outside the surface, achieving the purpose of lighting. There are two types of optical fibers: glass products and plastic products. Glass fiber optic is relatively thin and is widely used in water curtains, serving as both a water guiding device and a slender lighting strip. Plastic fiber optic cables are used for water feature lighting, but in music fountain lighting, plastic fiber optic cables are rarely used for main lighting due to their poor real-time performance, insufficient illumination, lack of primary and secondary distribution of illumination, and too few variations. They are generally used more in static environments.
Control of digital lights
The most commonly used digital LED underwater lights are dimmable three channel LED lights, typically driven by a 24V DC power supply. Each of the three channels represents a color, and the mixing ratio of the three colors can be adjusted simultaneously. Like stage lighting, most use DMX512 communication protocol for control, or adopt fieldbus network structure for control.
A networked lighting control system based on TCP/IP protocol, which can achieve bidirectional transmission, status reporting, remote control, resource sharing, etc., has many functions, and many manufacturers are doing this [2]. In most cases, the control cabinet of the fountain and the fountain pool are several hundred meters apart, and there are two types of network transmission methods: 1) coaxial cable or unshielded twisted pair electrical signal transmission, which are too close and generally cannot meet the communication requirements of the fountain site. Moreover, in places where a large number of motors are used, interference is severe, and underwater communication is even more difficult; 2) Using fiber optic communication requires placing the optical transceiver underwater, which is also impractical. So network communication can only be used for communication between the main control computer and the electrical control cabinet, and is unlikely to be used for on-site underwater equipment.
On site equipment often adopts differential electrical signal communication mode. Such as RS422/485, CAN bus or Profibus or Lonworks bus structure. In stage lighting performances, the DMX512 communication protocol is not only technically mature, but also widely used. A lighting system based on the DMX512 control protocol for dimming control is called a digital lighting system. Various stage lighting equipment, including computer lights, dimming controllers, control consoles, color changers, electric suspension rods, etc., have fully achieved digital dimming control with their comprehensive support for the DMX512 protocol. DMX512 communication protocol is used for fountain control.
The transmission of DMX512 signal adopts balanced transmission differential mode signal method, which can effectively suppress interference. Because interference signals are generally common mode applied to the positive and negative terminals of the signal, and then amplified by differential amplifiers. The common mode signals are mutually cancelled out, filtering out interference signals and effectively improving the system's anti-interference ability. The electrical interface standard for DMX512 signal is EIA-485 [3],
The transmission rate of DMX512 signal is 250kb/S, and the connection between devices adopts a daisy chain form. Each device has a physical address, and one DMX512 output port can control 512 control channels. The transmission distance of DMX512 signal is about 300 meters when using standard cables. The biggest drawback of DMX512 communication is the lack of checksum, which makes it impossible to achieve bidirectional handshake communication. In order to ensure the reliability of communication, the system adopts a continuous retransmission of data frames to suppress communication errors.
There are two types of connection methods for DMX512 lights: parallel connection and series connection. The parallel connection method refers to all DMX devices being connected to the DMX512 bus. The advantage is that a damaged device does not affect its operation, but each device has a different address. Due to the influence of the electric signal driven fan out system, according to the EIA-485 standard, each bus can carry 32 devices. Even if Maxim's 1/8 unit control technology is used, the theoretical upper limit of each bus load is 256 devices.
Parallel connection method: Tuopu structure
The serial connection method refers to the DMX512 device having a communication input line and a communication output line. The communication output line of the previous device is connected to the communication input line of the next device, and the devices are connected hand in hand. The previous device is responsible for transmitting data to the next device and shaping and amplifying communication signals. Each device only drives its own subordinate device without load capacity limitations. Communication theory can be infinitely expanded and automatic allocation of device addresses can be achieved without assigning numbers to the devices. The disadvantage is that if one device is damaged on the same line, all subordinate devices cannot work thereafter.
Serial equipment topology structure
Software Design
Digital LED underwater lights can achieve single light control. For fountain systems, the number of lights used is more than the number of nozzles, which invisibly doubles the number of control points. If so many control points are programmed and controlled one by one, it is a very troublesome thing and unnecessary. Like other management agencies, it is necessary to implement hierarchical management and set up separate categories to meet the needs of individual control and overall coordination. The following steps need to be taken for processing.
1) Classify and manage devices. Generally, digital LED underwater lights are 3-channel LED color changing lights, with each channel value ranging from 0 to 255. Channel 1 represents red, channel 2 represents green, and channel 3 represents grass blue. Each light occupies three bytes of DMX512, indicating the color value. Enumeration and classify the required functions: color synthesis such as yellow, green, red, white, blue, purple, cyan, etc., action enumeration such as fixed color and fixed brightness, fast gradient color, slow gradient color, light intensity and music follow-up functions for processing. For other DMX512 devices, such as 18 channel computer lights, they can also be processed through a combination of channel enumeration and function methods.
2) Specify the device type for a single DMX512 device. Match each DMX512 device with a device classification one by one.
3) Classify and manage devices, such as which type of water, how many lights are included, and where they are located on the DMX512 communication line.
4) Specify the performance mode for the classified devices. The performance method is a combination of equipment classification, managed and allocated through different combinations to complete a certain action performance plan.
5) Perform various performance styles according to time intervals and string them together to form a complete performance style.
After the following five steps of work, the configuration software is very easy to use for single lamp control and music matching, with only a limited number of choices. Just like an army, the commander classifies and processes individual digital LED underwater lights based on their functionality through the hierarchical management of commanders, division commanders, regimental commanders, company commanders, platoon leaders, and squad leaders. It is impossible for upper level software to directly command a single light, just like the commander directly manages soldiers, which is an impractical solution.
Future prospects
The application of digital LED underwater lights in fountains has just begun, and they can achieve the expressive effect of stage lighting. The rich lighting effects enhance the infectiousness of water type performances, and the use of fountain water type performances is more shocking. The dynamic effect of fountain artificial landscapes is more obvious, especially in the application of music fountains. Integrating music, water type, and lighting better reflects the beauty of rhythm and melody, allowing people to fully share the sensory stimulation and pleasure brought by sound, light, and electricity, better meeting people's increasing requirements for cultural life, and ushering fountain art into a new era.
Conclusion
The single lamp control scheme for digital LED underwater lights is feasible, reliable, technologically advanced, and has a bright future in fountain applications.