Application scheme of GPRS urban water supply disp

The application scheme of GPRS urban water supply dispatching and monitoring system

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the main purpose of the urban water supply dispatching and monitoring system is to solve the data collection and monitoring of water supply companies on the monitoring points of all links of water supply. The system is composed of the monitoring center and each water source monitoring point. The data acquisition terminal (RTU or PLC) of each water source monitoring point can monitor and collect various data such as water level, pressure, flow, turbidity, residual chlorine, pump frequency, etc. for the control center and relevant departments to analyze and make decisions, so as to improve work efficiency, ensure water supply quality, and meet the increasing demand for water consumption

the urban water supply dispatching needs to manage each water plant, including the control center of the water company, the sub control center of the water plant, the pipe pressurization station and the water source monitoring station. Urban water supply dispatching system generally includes: Water Department control center, multiple water plant sub control centers, multiple water plant monitoring sub stations, multiple water source well monitoring stations, multiple pipe pressurization stations and multiple pipe pressure measurement stations

the urban water supply dispatching and monitoring system can monitor and control the operating equipment at the remote site, so as to realize the data transmission of pipeline pressure and water flow and the automatic control of valve switch, reduce the failure rate and improve the response time to the system. It is convenient for timely and rapid understanding and control of remote pipelines and valves, low failure rate and maintenance time, and reduce the number of water outages. The data acquisition terminal of each water source monitoring point can automatically collect the real-time data of pipeline pressure, water flow and switch status, and the information is transmitted to the monitoring center of the water company. The monitoring center can find the location of the fault by analyzing the transmitted data, so that when a remote end fails, it can solve the problem in the shortest time, restore water supply, and improve the overall service level, Thus realizing the informatization and modernization of urban water supply

at present, the data communication used in the tap water supply dispatching and monitoring system can be simply divided into two categories: wired communication mainly includes erecting optical cables, cables or renting telecommunication lines, X.25, DDN, ADSL, etc., while wireless communication includes ultrashort wave communication, spread spectrum communication, satellite communication, GSM short message/gprs communication, etc

in the urban water supply dispatching and monitoring system, due to the wide distribution range, large number and long distance of monitoring points of each pipe, and the remoteness of individual points, it is difficult to erect optical cables and lay cables when the test results show that the tensile strength of one test piece is lower than the specified index. It is unrealistic to rent special lines from the telecommunications department, and it is also difficult to apply for many lines, and some monitoring points are difficult to reach, Moreover, when using the line, it needs to wait for a long dialing process, which is slow and has high operating costs. In short, the wired communication mode adopted by the monitoring system has long construction cycle, difficult work and high operating costs, which is not convenient for large-scale use; In contrast, wireless communication is very flexible. It has the advantages of less investment, short construction cycle, simple operation and maintenance, and high cost performance. In the monitoring system, wireless communication methods mainly include: ultra short wave (230MHz) wireless data transmission, spread spectrum, satellite communication, GSM digital cellular communication system, etc. among them, satellite communication is only used in some special fields because of its high communication cost, which has not been popularized; Although the spread spectrum communication technology has high speed, it can only transmit within the range of line of sight, and its application is also limited. Using ultrashort wave data transmission radio as the transmission channel has the advantages of flexible group, easy expansion, convenient maintenance and low operation cost. However, due to the system working at 230MHz and using ordinary indirect modulation data transmission radio, the system is vulnerable to external interference, low communication rate, high bit error rate, small data transmission volume, small signal coverage and other shortcomings

II. Scheme selection

after comparative analysis, we choose GPRS system of China Mobile as the data communication platform of urban water supply dispatching and monitoring system. At present, after years of construction by the telecommunications department, the GSM network has expanded its coverage and has become a mature, stable and reliable communication network, especially the GPRS data service newly launched by China Mobile

gsm/gprs system can provide wide area wireless IP connection. The construction of tap water supply dispatching and monitoring system on the GPRS service platform of mobile communication company to realize the wireless data transmission of pipe monitoring points has the advantages of making full use of the existing network, shortening the construction cycle and reducing the construction cost, and the equipment installation is convenient and the maintenance is simple

gprs wireless monitoring system has the following characteristics:

1. Good real-time response and processing ability. Compared with short message service, GPRS has real-time characteristics, and the system has no time delay. The system can receive and process various data of multiple/all monitoring points in real time at the same time. It can synchronize the clock of monitoring points without round robin, which can well meet the requirements of the system for real-time data acquisition and transmission

2. Remote instrument and equipment control: since GPRS bidirectional tensile testing machine can be used to call out the experimental curve transmission system again after the experiment, the monitoring center can reverse the time correction, status report, switch and other monitoring and control functions of instruments and equipment

3. Low construction cost: the existing GSM network can be fully used, and the equipment can be connected immediately after installation. When using ultrashort wave communication, the on-site environment needs to be fully considered, and the antenna iron frame and other auxiliary equipment need to be equipped

4. Simple installation and debugging, short construction cycle: using the existing mature GSM network, the system basically does not need debugging when it is put into operation, and the installation is simple. When ultrashort wave communication is adopted, the installation and commissioning workload is large, so the on-site signal test, antenna iron frame erection, antenna direction angle commissioning and other work should be carried out first

1. Wide coverage. The construction of water supply dispatching and monitoring system requires a wide range of data communication, unlimited capacity expansion and unlimited access locations, which can meet the access needs of mountains, towns and cross regions

due to the large number of pipe monitoring points, they are distributed throughout the city, and some pipe monitoring points are located in remote areas with scattered geographical locations. Ultra short wave communication mode is adopted, and the coverage is only more than 30 kilometers; With GPRS mode, monitoring can be realized theoretically within the coverage of wireless gsm/gprs network

2. High data transmission rate. GPRS network transmission rate can reach 171.2kbit/s in theory, and the data transmission rate in practical application is about 40kbps. At present, the transmission rate of general ultrashort wave data transmission stations is mostly 2.4kbit/s or lower

3. The transmission capacity of the system is large. The monitoring center station shall cooperate with each supervisor