1. In recent years, with the development of computer technology, computer technology has been widely used in various industrial production processes. Most of the large and medium-sized street lighting monitoring systems currently under construction or transformation use DCS systems, but there are many small and medium-sized The monitoring system is still in a relatively lagging phase of automation, still using traditional instruments or even manual monitoring. The cost of large DCS systems is relatively high, and general municipal technical reforms are also difficult to accept. The I-7000 series of remote I/O modules and industrial computer-developed low-cost DCS systems are the perfect solution to meet this need.
Second, the system plan proposed
The system uses a computer (ie, a master station) to control the entire campus street light. The computer is connected to campus Ethernet. Through Ethernet and ADAM-6500 communication, ADAM-6500 converts information into RS-485 communication mode and control module I-7060 communication, I-7060 control relay, and then drives the contactor to achieve on/off control of street light.
The campus is divided into several districts, each with a control room (sub-control point), a switch in the room can be connected to the control center computer, and the control room can also manually control each zone. The switch and the ADAM-6500 are placed in the control room and communicate with the control box via RS-485.
Third, the hardware design
1, system composition
The campus streetlight control system consists of three parts: the central control computer, the line terminal, and the street light control box. The control network is shown as 1.
The control center computer is the center of the system. The requirements are: support for computer systems above Window s98, with Ethernet interface. The monitoring center can be located anywhere on the campus and communicates to the line terminals via Ethernet on campus.
The line terminal - the intermediate level, communicates upwards with the monitoring center through the Ethernet in the campus, and communicates with the control module downward. This system uses ADAM-6500 as the Ethernet communication module, communicates with the central computer through Ethernet, and communicates with the control module I-7060 through RS-485.
Street light control box - is the terminal of the system, receiving the control command of the control center to control the lighting of the street light.
The system control network can be used for campus Ethernet, and the street lamp power supply uses the campus low-voltage power grid. Through the control of the system, it can be achieved: automatic power-off and power-on control for each street light; and the number of lights of the road can be controlled to achieve energy saving.
2, street lamp control principle
When I-7060 normally open contact KA is closed, 24V voltage is connected, 1KA coil is charged, 1KA contact is closed to make 1KM coil charged, 1KM contact is closed, and street lamp is lit to realize control of street lamp.
The I-7060 contact capacity can pass the maximum current of 2A, and the DC voltage does not exceed 30V, so 24VDC is used to drive the medium relay. The rated current of the medium-sized relay is generally about 5A. It is used to drive the 100W bulbs connected by parallel circuits. The current flowing through each lamp is about 0.5A, so it can only drive up to 10 bulbs. We designed to use a switch to drive 15-20 bulbs, so the total trunk current is about 5-10A. The relay obviously can't drive such a large current, but the AC contactor can, so first use the relay to drive the AC contactor. The AC contactor is used to drive the load to control the multiple lamps.
Fourth, the software introduction
1, the overall operating interface of the system
Start C + + Builder to enter the program, and the running interface appears as shown. The manual time switch can input the time of turning the light on and off at any time. As long as the input time is consistent with the system time, the system will automatically act. The function of the manual selection switch is that the user can turn on and off the lights to add the control path name function for different users to expand and use. The function of adding the number of control channels is to freely define the name of the road controlled by the module. The data query provides the user with the query data. When you click this button, the running status of all street lights will appear, including voltage, current, power consumption and running date. The lighting status display can be used by the control personnel to conveniently tell the operator which street light is running. Distributed control provides a single operating interface, in which case only one of the operating conditions can be displayed. The current and voltage states are displayed for the operator to observe the operating status of any one of the channels. Since the devices required for this system have not yet been fully purchased, there is no display of voltage and current for the time being. However, in the experiment, we used a regulated power supply instead of the analog quantity converted by the WB series voltage and current conversion module. The experiment can be successfully executed according to our design idea, and it is very accurate. The analog quantity is read by floating point data. . We can make the voltage, current and power output in a more reasonable format according to our own ideas in the program.
2, system program controls and main variable description
In this system, Label tab, Butt on button, CheckBox multi-select button, Edit edit box, DateSourse database, Table data list, Timer timer, NAP7000X, OCX control, GroupBox and other controls are used. Label is used to output some controls. Name, Butt on click on it to execute the program, CheckBox multi-select button is mainly used to select a single road segment in the program, DateSourse and Table are mainly used to edit and connect to the database, NAP7000X control module action, Timer control can be given The corresponding program is executed at intervals, and four Timer controls are used in the program. The two intervals are 1 second and the two intervals are 10 seconds. The variables used in the program are all displayed as global variables, so that the required variables can be called in any subroutine, which is convenient for passing values.
Unsigned char bValue; String ch user input time String dh sub-string X sometimes time of the string String m call system time String V < 4>, p < 4>, I < 4> voltage, current, power String Current, Voltage AC and DC Voltage and current sensor coefficient String z control path total String LookupResult database query result String jj is selected single path name float fBuf < 8> analog read back int P < 4> total power
Five, design summary
This system adopts Newton 7000 series products with high-performance computer to realize the control of street lamps. It has telemetry, remote signaling and remote control functions. It can send switch lights at any time according to needs, and can detect each node station periodically and randomly. Run data, through data analysis, get the status of the line, lighting rate and power consumption and other related data, through the system operation or telemetry of individual nodes, the data will be analyzed, you can judge the line leakage, line short circuit, power failure or Fault types such as power supply side fuse blow, short circuit fault, over/under voltage and over current. Through this system, the automation degree of street lamp control can be greatly improved, the waste of electricity consumption can be saved, the work efficiency of street lamps can be improved, and the contribution of the city beautification can be made.
On-Grid Inverter converts DC power to AC power for feeding back to the grid. The frequency of the output voltage of the grid-connected inverter needs to be the same as the grid frequency (50 or 60Hz), which is generally achieved by the oscillator in the machine, and the output voltage will also be limited not to exceed the grid voltage. Modern high-quality grid-connected inverters can have an output power factor of 1, which means that the output voltage and current phases are the same, and the phase difference between them and the grid voltage is within 1 degree. There is a microprocessor in the inverter that can sense the AC waveform of the grid, and according to this waveform, generate voltage and send it back to the grid. However, the electricity sent back to the grid needs to have a certain proportion of reactive power, so that the power of the nearby grid is within the allowable limit. noon) its voltage may rise too high.
If the power of the grid is cut off, the grid-connected inverter needs to be disconnected from the grid quickly. This is a regulation of the National Electrical Code (NEC) in the United States to ensure that when the grid is out of power, the grid-connected inverter will not provide power to the grid, and at this time the workers who maintain the grid will not be electrocuted.
Properly configured, grid-tie inverters allow a home to use alternative energy sources that it generates itself (such as solar or wind power) without cumbersome wiring and without the need for batteries. If there is insufficient alternative energy, the insufficient part will still be provided by electricity from the grid.
Grid-connected inverters are widely used in household photovoltaic power generation systems, commercial and industrial photovoltaic power plants and other scenarios. By connecting to the grid, they help to achieve efficient use of renewable energy and reduce carbon emissions, promoting sustainable development and popularization of clean energy.
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