1. Introduction:
    With the rapid development of information technology and social progress, the popularity of high-power LED lighting applications, LED lighting and efficient people to control and functionality required to improve diversity, LED intelligent lighting emerged as required. LED intelligent lighting systems make full use of electronic technology, communication technology and computer network technology to a variety of building an organic LED lighting apparatus connected to achieve effective management and control.
 
Keywords: Ethernet, LED, TCP / IP, DMX512, DALI, RS-485, DMX-NET
 
2. Ethernet, TCP / IP Description:
    Ethernet (Ethernet) LAN is a computer networking technology. IEEE developed IEEE 802.3 standard Ethernet technology standards are given. It provides, including the physical layer connection, electrical signal and the content of media access layer protocol. Ethernet is the most widely LAN technology. It largely replaced the other LAN standards such as token ring, FDDI, and ARCNET. Ethernet standard topology for the bus topology, but the current Fast Ethernet (100BASE-T, 1000BASE-T standard) to the greatest degree of reduction of conflict, the greatest increase network speed and efficiency, use of switches (Switch ) to make network connections and organizations, such Ethernet became a star topology, but still use the Ethernet logical bus topology and CSMA / CD (Carrier Sense Multiple Access / Collision Derect that with Collision Detection Carrier Sense Multiple Access) technology bus contention.
 
   TCP / IP protocol set is currently the most widely used network data transfer protocol, which is the main body of well-known Internet protocol. TCP / IP protocol is the basic transmission unit of the packet. TCP protocol is responsible for the data divided into packets, and add to each packet header, (like a letter with an envelope) has a corresponding number on the header to ensure that the data in the data receiver can restore order the original format. IP protocol on top of each header address of the receiver device, such data can find its destination. (As stated on the envelope to the same address) If data loss occurs during transmission, data distortion, etc., TCP protocol will automatically require the data re-transmission. IP protocol to ensure data transmission, and therefore addresses the agreement. TCP protocol to ensure data quality, it is a transmission control protocol.
 
3. DMX512 Description:
    Practitioners will know about lighting such an agreement, it is the light of today 's most widely used communication protocol. For USITT (United States Theatre Technology Association) to Colortran 's CMX192 in Band rate from 153.6Kbit / s upgraded to 250Kbit / s and into 512CH 192CH issued (CMX and DMX structure will be similar). When originally published in Mark After Break (MAB) for the 4uS, found in the subsequent application to refresh the problems often signal the MAB extended 8uS and is defined as the DMX-512 (1990) version. Its widespread use is due to simple structure, low cost, easy to understand and so on, major companies have to DMX512 interface to add products. DMX512 protocol successful promotion and we are happy to use another major contributor to a few decades the rapid development of computers and a large number of lamps used in large-scale performances in. DMX512 is still a new area of science, with rules-based technology for a variety of wonderful.
 
   DMX512 control cable with 5 pin XLR (sometimes 3-pin) to connect devices, home interface, suitable for transmitter, while the public interface for the receiver. Specification suggested a two pairs of wire (4 connector) to implement screening, although only need one pair. Second pair of wires for the optional is not specified occasions. Should be noted that a number of dimmers to use these lines to indicate the fault and status information. Used if Dimmer second channel, you need to specifically configure the splitter and repeater.
 
   Pin XLR connector port as follows:
   A shield in / 0 V
   2 internal conductor (Black) data -
   3 internal conductor (white) data +
   4 internal conductor (green) alternate data -
   5 internal conductor (red) data + backup
 
4. LED control system for the industry mainstream:
    4.1: Serial control system to control the cascade manner, each light signal into a line with one way. Representative products and compatible with standard 595 chip, such as Taiwan point crystal DM134, 135 and so on. Because of this control method does not produce the chip itself is gray, gray to the controller if you need to generate, resulting in the system transmission rate is too high, in engineering applications vulnerable to complete the interference stability of the difference.
 
    Advantages: low cost, simple control, do not set the address, for some stability, high reliability requirements of the project can not use this control method.
 
    Disadvantages: signal line too, usually five signal lines (clock, data, latch, OE, land).
As a result of entering and exiting way, leading to a lamp fails, the effect of a string of lights are working.
Signal transmission by TTL, the distance between the lamp and the lamp can only be within 1 meter.
Non-standard systems, lighting and controller must be the same manufacturer 's product, otherwise they can not be compatible.
 
   4.2: Fieldbus control system, which DALI bus and RS485 bus into two categories.
 
4.2.1 DALI Description:
    The late 90s of last century, developed the DALI standard lighting industry (Digital Addressable Light Interface). The Digital Addressable Lighting Interface is designed to replace the traditional lamp ballasts for dimming 1 ~ 10V voltage interface. DALI defines a standardized digital ballast interface, not dependent on any manufacturer 's DALI standard has been as IEC60929 international standard, ensuring different lighting ballast vendor interoperability. DALI components to create a flexible, low-cost, open distributed generation digital lighting systems. This new open standard for the future of lighting control solutions business has a great influence, it is fundamentally changing the traditional 1 ~ 10V voltage based on the interface the way lighting control solution.
 
    DALI DALI standard has defined a network consisting of 64 units (can be separate address), 16 groups and 16 scenes. DALI bus lighting units can be flexible in different groups to achieve control and management of different scenarios. In practice, a typical DALI controller up to 40 ~ 50 light, can be divided into 16 groups, while a number of actions to parallel processing. In a DALI network, capable of handling 30 to 40 per second, a control command. This means that the controller for each lighting group, need to manage two per second dimming command. DALI is not a true peer to peer network, it is instead of 1 ~ 10V voltage interface to control ballast. DALI controller is usually connected to the network of more advanced equipment, such as Ethernet, to support more devices and adequate network bandwidth.
 
   Obviously not suitable for LED lighting control DALI, DALI network can only control a full-color LED lamps 21. DALI is for the traditional lighting control, the focus is the system of static control and reliability, stability and compatibility. The LED lighting system is much larger than the size of DALI system, the main effect of the pursuit of artistic expression lamp, proper balance between the intelligent system, which requires a system with unlimited scalability and high capacity to refresh the scene.
 
4.2.2 RS-485 Description:
    RS-485 standard originally developed by Electronic Industries Association (EIA) in 1983 to develop and publish, after the TIA-Telecommunications Industry Association revised named TIA/EIA-485-A, but still likes to call the engineers RS-485. RS-485 evolved from the RS-422, which is to compensate for the lack of RS-232 made. RS-232 communications to improve the short distance, low rate of defects, RS-422 communication interface defines a balance, the transfer rate up to 10Mbps, to extend the transmission distance to 4,000 feet (when rates of less than 100kbps), and allows a balance online to connect up to 10 receivers. RS-422 is a single send, receive one-way multi-machine balanced transmission standard, for the expansion of application scope, then added more points to its two-way communications capability, which allows multiple transmitters connected to the same bus, while increasing the transmitter power and conflict drive protection features, expanded bus common mode range, which is later EIA RS-485 standard.
 
   RS-485 is an electrical interface specification, it only provides a balanced driver and receiver electrical characteristics, but does not require connectors, transmission lines and communication protocols. RS-485 standard defines a single pair of balanced line-based multi-point, two-way (half-duplex) communication links, is a very economic and has a very high noise immunity, transmission rate, transmission distance and wide common mode range of communication platform. RS-485 interface, the main features are as follows:
1. Balance Transfer
2. Multipoint communication
3. Driver output voltage (with load) ≥ 1.5V
4. Receiver Input Threshold: ± 200mV
5.-7V to +12 V bus common mode range
6. Maximum input current: 1.0mA/-0.8mA (12Vin/-7Vin)
7. 's Largest bus load: 32 unit load (UL)
8. Maximum transfer rate: 10Mbps
9. Maximum cable length: 4000 feet
 
   RS485 provides only the physical layer, leaving room for the vendors to take. A variety of field bus in the world (including DMX512) are using the RS485 physical layer protocol. In the field of LED lighting control, we common practice is for each LED lamp built-in MCU control and an RS485 interface chip connected through to the RS485 bus, using a controller on the RS485 bus to send data to each MCU control. Because of this control method needs to set the address for each lamp, very convenient for engineering applications. Although each control system vendors are using RS485 protocol, but the application layer standards are still not reunited, with the result that the products can not be compatible with various manufacturers, Ji lamps lighting manufacturers lighting manufacturers You can specify the control system of control.
 
5. DMX-NET System description:
    As computer network technology, DMX512 standard of popularity and rapid development in the field of LED lighting control, computer network using existing mature technology, DMX512 standard, and products are very sensible approach. Use of Ethernet, TCP / IP, DMX512 LED lighting control as a means of network with large number of ready-made products, software resources, DMX512 products. Such as console, hubs, cables, fiber optic and wireless connectivity products and remote control and monitoring technology, in addition to the existing building and the various places all over the Ethernet has been more conveniently temporary use of LED lighting project.
 
   Based on the above factors the Company to calculate the standard DMX512 network technology and integrated, new generation LED intelligent lighting control system "DMX-NET" system. The system integration of the advantages of both technologies, so that the system bandwidth, distance, reliability, and the realization of two-way functions, which means the network can connect a device more, and longer distance connections, transmission control agreement to control LED lighting system quality and reliability, two-way communication to remote monitoring and control equipment more efficiently, thus building large reliable network of LED lighting systems at lower costs.
 
5.1 DMX-NET system architecture:
    DMX-NET system is based on TCP / IP protocol and DMX512 protocols, the transport TCP / IP protocol in the backbone network and subnet DMX512 protocol composition.
 
 
5.2 DMX-NET system component functions:
    Basic PC-DMX-NET platform, management software, the center of the whole system, the function responsible for the control of the system and receive remote control signals to control, such as time control, scene control, on-site control of the artistic effect.
 
  Network node controller is responsible for receiving system sends a TCP / IP protocol data, while the TCP / IP protocol data into DMX512 DMX512 protocol data sent to the device.
 
  DMX Decoder function is to receive DMX512 data into PWM signals control the LED lights dimming or switching.
 
  Data flow throughout the system to switch from computer to the Ethernet network node to DMX512 DMX Decoder.
 
5.3 DMX-NET Network Topology:
    DMX-NET system backbone network will use TCP / IP protocol to transmit data, and does not require the physical layer transmission media, the user can select the appropriate network size according to the type of network, a large fiber optic LED lighting project to transfer data more suitable choice, small LED lights Project Select Ethernet data.
 
   DMX-NET system subnet using standard DMX512 protocol, data, and settings for the DMX512 start address launch three kinds of solutions to effectively overcome the traditional DMX512 equipment necessary DIP switch to set the DMX512 start address the problem.
 
Write to adopt DMX DMX Decoder manually set the start address.
Write to adopt DMX DMX Decoder automatically set the start address.
DMX start address adaptive technology, this program does not need DMX Address Writer to set DMX start address. DMX Decoder system automatically configure DMX start address.
6. Conclusion:
    DMX-NET system has been widely used in urban night lighting project and indoor decoration lighting and display projects on the performance capabilities of color, lighting control, environmental protection and energy saving links to the people a new vision. Combination of network technology, DMX512 technology, new intelligent LED lighting control system is bound to human culture, lighting concepts and lighting to bring a new revolution.
References
[1] DMX512 protocol
[2] "TCP / IP Practical Technology Guide" [U.S.] MFArnet Tsinghua University Press, etc.