Application of GPRS in the water industry

I. project background
The main purpose of the urban water supply network scheduling and monitoring system is to collect and monitor the data of water supply companies in various monitoring points. The system consists of a monitoring center and a water source monitoring point. The data collection terminal (RTU or PLC) of each water source monitoring point) it can monitor and collect various data such as water level, pressure, flow rate, turbidity, residual chlorine and Pump Frequency for analysis and decision-making of control centers and relevant departments, improve work efficiency and ensure the quality of water supply, meet the demand for increasing water consumption.
City Water Supply scheduling needs to manage various waterworks, including the control center of the tap water company, water plant control center, pipe network pressure station and Water Source Monitoring Station. The urban water supply scheduling system generally includes: water Control Center, multiple water plant control centers, multiple Water Plant Monitoring substations, multiple water source well monitoring stations, multiple Pipe Network pressurization stations and multiple pipe network pressure measurement stations.
The city water supply scheduling and monitoring system can monitor and control remote on-site operation equipment to realize data transmission of pipeline pressure and water flow and automatic control of valve switches, this reduces the failure rate and increases the response time to the system. It facilitates timely and rapid understanding and control of remote pipelines and valves, low failure rate and maintenance time, and reduces the number of water stop times. The data collection terminal of each water source monitoring point can automatically collect the real-time data of pipeline pressure, water flow, and switch status, and transmit the information to the monitoring center of the Water Supply Company, by analyzing the transmitted data, the monitoring center can locate the fault location. When a remote fault occurs, the monitoring center can solve the problem and restore the water supply in the shortest time, it has improved the overall service level, thus realizing the informatization and modernization of urban water supply.
Currently, the data communication used in the water supply scheduling and monitoring system can be divided into two categories: wired and wireless, among them, wired communication mainly includes the establishment of optical cables, cables or leased telecommunications lines, X.25, DDN, ADSL, etc, wireless communication includes ultra-short frequency communication, spread-spectrum communication, satellite communication, and GSM Short Message/GPRS communication.
In the urban water supply scheduling and monitoring system, some monitoring sites are still remote due to the wide distribution, large quantity, and long distance of various network monitoring sites, therefore, it is difficult to set up optical cables and lay cables. Therefore, many telephone lines need to be applied for leased lines from the telecommunications department, and some monitoring sites are difficult to reach, in addition, when using telephone lines, you need to wait for a long dialing process. The speed is slow and the operation cost is high. In short, the monitoring system uses wired communication mode for a long construction period, which is difficult to work, and the operation cost is high, it is not easy to use on a large scale. In contrast, the wireless communication mode is very flexible. It has the advantages of low investment, short construction period, simple operation and maintenance, and high cost effectiveness. In the monitoring system, wireless communication methods mainly include: ultra-short wave (230 MHz) wireless data transmission, spread spectrum, satellite communication, GSM digital cellular communication system, among which satellite communication is expensive due to communication costs, it is only used in some special fields and has not been popularized. Although the spread spectrum communication technology is of high speed, it can only be transmitted within the line of sight, and its applications are also limited. The use of ultra-short frequency data transmission stations as transmission channels has the advantages of flexible networking, easy expansion, convenient maintenance, and low operating costs. However, because the system works at MHz and most data transmission stations adopt common indirect modulation, as a result, the system is vulnerable to external interference, low communication rate, high error rate, low data transmission volume, and low signal coverage.
Ii. Solution Selection
After comparative analysis, we chose China Mobile's GPRS system as the data communication platform of the urban water supply scheduling and monitoring system. At present, the GSM network has been built by the Telecom Department for many years and covers an ever-expanding range. It has become a mature, stable and reliable communication network, especially the new GPRS data service launched by China Mobile. The GSM/GPRS system provides wide-area wireless IP connections. The water supply scheduling and monitoring system is built on the GPRS Service Platform of mobile communication companies to realize wireless data transmission of pipe network monitoring points. It has the advantages of making full use of the existing network, shortening the construction cycle, and reducing the construction cost, moreover, the device is easy to install and easy to maintain.
The GPRS wireless monitoring system has the following features:
1. good real-time response and processing capabilities. Compared with short message service, due to the real-time online feature of GPRS, the system has no latency, and the system can collect and process various data from multiple/all monitoring sites at the same time, the clock of the monitoring point can be synchronized without wheel inspection, which can meet the requirements of the system for real-time data collection and transmission.
2. Remote Instrument and Equipment Control: With the GPRS bidirectional transmission system, the monitoring center can reverse implement time correction, status report, switch, and other monitoring and control functions of the instrument and equipment;
3. Low construction cost: the existing GSM network can be fully utilized, and devices can be connected immediately after installation. However, when using ultra-short wave communication, the on-site environment should be fully taken into account, and ancillary equipment such as antenna iron frames should also be provided.
4. simple installation and debugging, and short construction period: using the existing mature GSM network, the system does not need to be debugged when it is put into operation, and the installation is simple. The installation and debugging work is heavy when ultra-short wave communication is used. It is necessary to perform on-site signal testing, erection of antenna iron frame, and commissioning of antenna direction angle.
1. wide coverage. The construction of a water supply scheduling monitoring system requires a wide range of data communication coverage, unlimited resizing, and unlimited access locations, which can meet the access needs of mountainous areas, towns and cross-regional areas.
Due to the large number of pipe network monitoring sites, some pipe network monitoring sites are located in remote areas and their geographical locations are scattered. Ultra-short wave communication is adopted, with a coverage of more than 30 kilometers. However, GPRS can be used to achieve monitoring in theory within the coverage of wireless GSM/GPRS networks.
2. High data transmission rate. In theory, the GPRS network transmission rate can reach 171.2 kbit/s, and the actual data transmission rate is around 40 kbps. At present, the average transmission rate of ultra-short wave data transmission stations is 2.4 kbit/s or lower.
3. The transmission capacity of the system is large. The monitoring center must be connected to each network monitoring site in real time. Due to the large number of pipe network monitoring sites, the system requirements can meet the needs of sudden data transmission, and GPRS technology can meet the needs of sudden data transmission.
4. Low communication costs. Because GPRS uses the monthly billing method, the operation and maintenance costs are low, and the monthly communication fee will be less than 200 RMB. Iii. solution introduction
Because GPRS communication is an IP address-based Data grouping communication network, the host of the monitoring center is configured with a fixed IP address, and the GPRS module of each end station communicates with the host.
(1) system composition
1. Pipe Network Monitoring site:
Pipe Network Monitoring site: each monitoring site collects data such as pressure and traffic through the data collection module, and connects to the GPRS transparent data transmission terminal through the RS232 interface, the embedded processor is embedded in the GPRS transparent data transmission terminal to process the data, encapsulate the protocol, and send it to the GSM network.
2. Monitoring Center:
The server requests to configure a fixed IP address and uses the ddnleased line provided by the provincial mobile communication company to connect to the GPRS network. Because the ddnleased line provides high bandwidth, when the number of monitoring sites in the pipe network increases, the center does not need to be resized to meet the requirements.
The RADIUS server of the monitoring center performs AAA authentication after receiving data from the GPRS network, and then transmits the data to the Computer Host of the monitoring center. The system software restores and displays the data and processes the data.
3. GPRS/GSM mobile data transmission network:
The data collected by the on-site monitoring site is decoded by the GSM network air interface function module and converted to the public network data transmission format. The data is transmitted through China Mobile's GPRS wireless data network, the IP address is finally sent to the monitoring center.
(2) system solution
Each monitoring site uses a GPRS transparent data transmission terminal to connect to the monitoring center through a mobile GPRS network.
The collection points of various pollution sources use the STK cards of mobile communication companies. At the same time, the monitoring center registers each point and stores relevant information for identification and maintenance. Each information collection point runs the monitoring system software, and supports 24 hours of real-time online, information collection point 24 hours to transfer the collected information data.
All information collection points authorized by the tap water company can use this system:
1. The Pipe Network Monitoring site must use a uniform STK card. You can only use this card for data communication with the monitoring center.
2. Terminal devices use the GPRS mobile data communication terminal provided by CCN.
3. User Registration: It complies with the regulations of the tap water company.
(3) Product Features
The system uses the SG2000 series GPRS wireless transparent data transmission terminal. The product is based on China Mobile's GPRS network and features high performance, high reliability and strong anti-interference ability, provides a standard 232 Data port that can be directly connected to computers, RTU, PLC, GPS receivers, digital cameras, and data terminals. The transmission rate reaches 171 Kbps, and supports remote diagnosis, testing, and supervision, data collection and control between scheduling or control centers in various industries and Multiple Remote stations.
1. supports 900/1800/MHz tri-frequency GSM/GPRS.
2. Interfaces: RS232, RS485, and PCMCIA.
3. The theoretical transmission rate is 171 Kbps, and the actual transmission rate is 40 Kbps.
4. Supports Windows 95/98/200/XP and LINUX operating systems.
5. Supports transparent data transmission and protocol conversion.
6. Supports VPN security.
7. Flexible installation, easy to use, and reliable.
(4) security measures
Due to the particularity of the water supply scheduling and monitoring system, the system requires extremely high system security and stability. Security Protection is mainly to prevent intentional and unintentional loops from inside and outside the system. network security protection measures include channel encryption, source encryption, logon protection, access protection, access protection, and firewall. Stability means that the system can run continuously for 7 × 24 hours. Even if a hardware or software fault occurs, the system cannot stop running.
The data center can connect to the mobile GPRS network through a VPN over the public network. The cost of using the VPN method is relatively low. enterprises do not need to rent a leased line, and they can also use the original VPN equipment, the mobile terminal must install software with the VPN secondary virtual dialing function. In VPN mode, before connecting to the application server, the client needs to pass the authentication of the Radius server. The entire data transmission process is encrypted and protected with high security, which fully guarantees the speed and network service quality.
In addition, the data center can also use the APN access method and lease a leased line to connect to the GGSN device of a mobile company. This is costly, highly secure, stable, and reliable.
For systems with high security requirements, you can consider adding a VPN access hybrid access method on the basis of dedicated APN access to further improve system security.
1. VPN Virtual Private Network Mode: configure the VPN Server in the internal network of the enterprise, and load the client software with the VPN secondary virtual dialing function on the mobile terminal. VPN security technology is used to isolate users from the Internet by connecting to the internal virtual private network of the enterprise, which can encrypt and protect the entire data transmission process, effectively avoiding illegal intrusion.
2. Use the uniqueness of the SIM card to authenticate and authorize the mobile phone number of the user's SIM card. On the network side, bind the SIM card number and the APN to define the scope of the user's access to a system, only SIM card numbers in the specified industry can access specialized APN. Mobile Terminals and data centers use specialized APN allocated by China Mobile for wireless network access. SIM card numbers of ordinary mobile phones cannot call specialized APN.
3. For specific users, specific user IDs and passwords can be allocated through the data center. Other users without user IDs and passwords assigned by the data center cannot log on to the system, and the security of the system is further enhanced.
4. Data Encryption: encrypt and protect the entire data transmission process through VPN.
5. Network Access Security Authentication Mechanism: firewall software is used to set network authentication and security protection functions to ensure system security.
Iv. Conclusion
Using GPRS to build a water supply scheduling and monitoring system, currently there are two charging methods: monthly subscription and data volume, 0.03 RMB/kbyte based on traffic, while 20 RMB/month based on monthly subscription has 1024 k of traffic, it can meet the actual data volume of the current monitoring system and is estimated that the cost will gradually decrease in the future. Users enjoy low communication costs. In addition, because the access equipment can be moved, the equipment can be migrated and used when the pipe network monitoring site is relocated, which can protect users' original investment and is suitable for the characteristics of water supply scheduling and monitoring, it can meet the needs of water supply monitoring, and as a network operator, mobile communication companies will also obtain stable group users. As the number of users increases, the revenue of mobile communication companies also increases, mobilizing the enthusiasm of operators and complying with the requirements for simultaneous development of network construction and network applications.

Our company has installed 100 flow meters on the internet, effectively reducing the production/sales ratio. Recently, the system began to install flow meters for large users. The instantaneous and cumulative values were monitored in real time to effectively prevent users from stealing water. If you are interested, contact us.

Yixing water group and Information Technology Co., Ltd. Contact person: Mr. Chen 13961501079