Design and Implementation of Group Controller in Road Lighting System of Journal of Lighting Engineering Liu Xiaosheng, Yan Yingfeng, Yan Jiajin, Xu Dianguo (School of Electrical Engineering and Automation, Harbin Institute of Technology, Harbin 150001), and implementation method, and introduced the main software structure block diagram of the system.
1 Proverbs â—Ž Figure shows the system composition of the digital road lighting system. BlingH.Allrights public lighting system widely uses high-pressure sodium lamps or metal halide lamps, traditional lighting systems generally use magnetic ballasts, lighting fixtures use electrical switch control scheme.
With the development of digital technology and network technology, the digitalization and networking of public lighting control has become an inevitable trend, saving energy, ensuring the life of lamps, improving the management level of lighting, beautifying the night view of the city, and ensuring the safety of night travel in cities. Become a basic requirement for public lighting systems. This paper will introduce the all-digital public lighting control system based on digital ballast. This system realizes the arbitrary monitoring of remote single street lamp nodes for the first time in China, and introduces the function, composition and working principle of a group of controllers of the core equipment of the system. The main software structure block diagram.
2 road lighting digital control system diagram. In this system, each lamp node adopts fully digital electronic ballast, which can realize 0%, 50%, 80%, 100% power output, can send current and voltage information of lamps at any time, and has open circuit, short circuit and lamps Aging alarm function. Each of the luminaire nodes includes a power carrier communication (PLC) module; the power carrier module is used to implement information communication between the luminaire nodes and between the luminaire nodes and the group controller. The group controller adopts a dual CPU structure, which is responsible for the normal operation control of the daily system, and can respond to commands issued by the upper management computer at any time. The group controller and the lighting management computer realize communication under normal conditions through GSM/GPRS short message mode. In the case of a failure of the group controller, the lighting management computer can directly realize the switch control of the lamp line through GSM/GPRS, and realize system safety double insurance. The lighting management computer uses Geographic Information System (GE) technology to realize graphical dynamic real-time monitoring and management.
3 group controller working principle and system composition 3.1 group controller working principle, it is a group of control objects (lamps) as a unit, according to the predetermined control strategy, independently monitor the lighting node object operation, and can respond to lighting at any time Manage computer instructions and update luminaire control strategies at any time. The control strategy mainly includes: (1) daily control strategy; (2) four season control strategy; (3) four season division strategy; (4) holiday control strategy. Various strategies are hardened in the E2PROM of the group controller. The number of control nodes (ie, control range) of each group controller is generally several tens of luminaires to several hundred luminaires. At the same time, the group controller is divided into a single-phase group controller and a three-phase group controller according to the difference of the number of phased power supply transformers. The following takes a single-phase group controller as an example to briefly introduce the specific technical solutions.
3.2 Group controller system composition gives a group controller design scheme. The utility model comprises a CPU module, a line state detecting module, an AC contactor driving module, a backup power module, a clock module, a control strategy module, an electric energy metering module, a temperature and humidity detecting module, a GSM communication module and a power carrier communication module. The CPU module uses a dual CPU structure. The main microcontroller uses high performance, 8-bit, 40-pin, 8KFlash, multi-channel 8-bit A/D, RISCPIC16F877 microcontroller, responsible for communication with GSM communication module and power carrier module, AC contactor drive control, real-time clock reading Take and calibrate and send control commands according to the lighting control strategy. From the microcontroller, the same series of high-performance 8-bit, 28-pin, multi-channel 8-bit A/D, 4KFlash, RISCffi, and 73 single-chip microcomputers are used in the same series as the main microcontroller. The controller has a negative 3.3 dual CPU communication method and RS485. Communication Although the peripheral communication interface of the PIC16F87x series MCU is rich, the communication of the whole system is complicated and the interface resources are still very tight. Reliable communication between the master and slave CPUs is one of the keys to reliable operation of the group controller.
The controller PIC16F873 uses an SPI interface and communicates in master-slave mode. According to system port configuration requirements, PIC16F873 uses hardware SPI interface mode, PIC16F877 uses common I/O port RB1RB3 to simulate hardware SPI port, which is software SPI interface. The SPI hardware resources of the PIC16F877 are allocated to the E2PROM24C64. The SPI interface of the PIC16F873 operates in slave mode. The PIC16F877 needs to select a common I/O port (here RB4) to connect to the SPI communication control terminal RA4SS of the PIC16F873 to control the initiation and termination of SPI communication, as shown. Each communication is initiated by the PIC16F877 and the PIC16F873 responds.
The energy metering module is a separate module that can measure the voltage, current, power, power factor and other parameters of the power supply line, and has a standard bath 485 interface. To this end, the PIC16F873 uses the hard serial port RCTX and RC7/RX to be connected to the energy metering module JP1 via the R485 interface. Here, the MAX485 chip acts as a 485 bus interface conversion chip, and uses RC2 as the RS~485 bus communication input/output as the control terminal, and the control signal is read in and sent out.
3.4 AC contactor control and state maintenance One of the important tasks of the group controller is to achieve lighting line power control through the solid state relay SSR and AC contactor. The solid state relay is a 324Vdc input with a 220Vac output and its input is driven by an NPN transistor 9013. Due to various interferences during the actual operation of the system, if the CPU control pin directly drives the transistor 9013 without anti-interference processing, the related pin may be hopping or tri-stated, causing the AC contactor to malfunction. Therefore, "locking" the state before reset is very important to ensure system reliability. A sample/hold circuit consisting of a D flip-flop, an optocoupler, three resistors, and three VO pins is used here. The D flip-flop reset terminal R and the set terminal S are respectively grounded, the data terminal D is connected to the data control terminal RE0 of the CPU, and the clock terminal CLK is connected to the clock of the CPU through the optocoupler TIP521 to generate the control terminals RE1 and RE2. The key of the hold circuit is RE0, A single pin fault in RE1 and RE2 cannot generate a valid clock and control command. Even if the CPU resets, the current working state of the solid state relay is read back by the RC0 pin, and the RE0 output (D flip-flop input) is set to this state, thereby ensuring that the SSR does not malfunction. Resistor R32 is a pull-up resistor to ensure that the optocoupler does not miswire when RE2 is tri-stated. Resistor R33 acts as a current limiter. Practice has proved that the circuit is effective.
Section dividing schedule Table2, seasonal control strategy schedule Table3 and holiday view table storage iROMdP 3.5-day clock and control strategy To achieve automatic timing control, system clock and system pre-stored control strategy are key. The group controller uses the DS1302 clock chip to provide a real-time clock for the system. The DS1302 is a high-performance, low-power clock chip with 8-pin, I2C serial communication with backup power supply. It provides seconds, minutes, hours, days, weeks, months, and years calendar functions. The fC serial bus SCL and SDA require a pull-up resistor, respectively. The main microcontroller PIC16F877 uses a hardware I2C interface (RCSCL and RC4/SDA) to communicate with the DS1302 as shown. The group controller can implement remote clock calibration.
in. 24C64 is an E2PROM with a capacity of 8kbytes, two-wire I2C serial communication, and 1000000 erasing. The main microcontroller PIC16F877 uses two common I/O ports (RD1 and RD2) to simulate the I2C serial bus, ie: implementation software I2C interface. The group controller issues switch lights and dimming control commands according to the read calendar information and time information, according to various control strategy schedules.
3.6 software implementation of the processor software. On one hand, the main microcontroller is responsible for communicating with the lighting management computer (referred to as the upper computer) through GSM, receiving, parsing and executing various commands sent by the host computer, and transmitting the execution result to the upper computer; on the other hand, the main controller In the absence of GSM information, complete some other tasks, the software block diagram is as shown. A brief block diagram of the software from the microcontroller is given.
4 Conclusion Urban road lighting control system is an important system involving urban streets, highways, airports, railway stations, landmark buildings, landscape buildings, etc. It is very difficult to establish a practical and reliable digital and networked road lighting control system. Due to space limitations, this paper only gives the key hardware design circuit and core software block diagram of the group controller, and many specific details are not elaborated. Experiments show that the system design is reasonable and reliable.
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