Foreword Due to the geographical dispersion of urban water supply, the requirements for acquisition and control functions are stable and the safety requirements are high. Generally, the original scheduling method of manual meter reading, telephone number reporting, and on-site manual operation is adopted. The number of collected information is small, the processing is slow, the transmission is late, and the scheduling is in a low-level stage, so as to ensure that there is no shortage of water and maintain normal operation, and that there is no optimal scheduling. In the event of an explosion or other accident, it reflected the expansion of the dull loss.
The urban water supply dispatch monitoring system can monitor and control the remote on-site operating equipment to realize the data transmission of pipe network pressure, water flow, etc., and the control of the water output of various water plants so as to facilitate timely understanding and control of remote production and operation conditions. Failure rate, shorten repair time, reduce the number of water stops. The data collection terminal of each pipe network monitoring point can automatically collect real-time data such as pipeline pressure and water flow. The information is transmitted to the water company's dispatch center. The dispatch center can analyze the transmitted data to find out the location of the failure. When a remote fails, the problem can be solved in the shortest possible time.
At present, the data communication used in the tap water supply dispatch monitoring system can be simply divided into two categories: wired and wireless, among which the wired communication mainly includes the installation of optical cables, cables or leased telecommunication telephone lines, X.25, DDN, ADSL, etc. while the wireless Including ultra-short wave communications, spread spectrum communications, satellite communications, GSM SMS / GPRS communications.
In urban water supply dispatch monitoring systems, because of the wide distribution, number, and distance of individual monitoring points of pipeline networks, individual stations are also located in remote locations. Therefore, it is difficult and costly to set up optical cables (cables) to lease dedicated telephone lines to the telecommunications sector. Many telephone lines have to be applied, and some monitoring points are difficult to reach. In addition, it takes a long telephone dialing process when the telephone line is used, which is slow and the operating cost is high and it is not practical. In short, the monitoring system adopts wired communication, which has a long construction period, is difficult to work, and has high operating costs. It is inconvenient for large-scale use. In contrast, wireless communication is very flexible. It has less investment, short construction period, and maintenance. Simple, cost-effective advantages.
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 used only in some special fields due to its high communication cost. It is popularized; while the spread-spectrum communication technology has a high rate, it can only be transmitted within the range of sightlines, and its application is also limited. The adoption of ultra-short wave data transmission radio as the transmission channel has the advantages of flexible networking, easy expansion, easy maintenance, and low operating costs. However, since the system operates at 230 MHz and uses common indirect modulation digital radio stations, this results in the system being vulnerable to external interference. Low communication rate, high bit error rate, small amount of data transfer, and small signal coverage.
After a comparative analysis, we chose China Mobile's GPRS system as the data communication platform for the water supply dispatch monitoring system. At present, the GSM network has been built by the telecommunications sector for many years and its coverage has been continuously expanded. It has become a mature, stable and reliable communication network, especially the newly launched GPRS data service of China Mobile. The GSM/GPRS system provides a wide area wireless IP connection. Constructing tap water supply dispatch monitoring system on mobile communication company's GPRS service platform to realize wireless data transmission of pipe network monitoring point has the advantages of making full use of existing network, shortening construction period and reducing construction cost, and convenient installation and maintenance of equipment. .
system structure
In order to meet the scheduling and command of the production process, a reliable SCADA system is needed. It is generally composed of enterprise production dispatching command center, water plant, pipe network pressure measurement point, meter reading telemetry and so on. Its functions generally include: data acquisition control functions, data transmission functions, data display and analysis functions, alarm functions, storage, retrieval, query functions of historical data, report display and printing functions, remote control functions, and network functions.
The pipe network measuring point SCADA automation control system mainly monitors the decentralized pipe network measuring point site. The system adopts two-level control. The first level is the central control room of the SCADA system, and the second level is the remote measurement and control terminal GPRS RTU of the pipe network measuring point. The central control office is responsible for monitoring, management and control. The site GPRS RTU is responsible for the data collection of multiple pipe network measuring point sites, wireless transmission, and automatic control of pipe network measurement point pressure.
The dispatch center monitors the pipe network monitoring points in real time and directs the water output of each water plant. It is the system's information collection and control center. The dispatch center collects the data information of each site, and stores, analyzes, summarizes, or prints such information. Through data analysis, timely alarm information is given or a control command is sent to the site to control the operation of the site equipment so as to realize the scheduling and management of the entire system.
GPRS RTU (Remote Measurement and Control Terminal) is the basic component of the SCADA system. Acquisition, control and communication are the basic functions he has. For enterprises with distributed, distributed, and networked features, the establishment of a SAS/SCADA system is inseparable from the GPRS RTU products. The SCADA system in the urban water supply integrated automation system must have and is a very important function: to monitor the flow, pressure, and other changes in the water supply network throughout the city in real time and accurately. The GPRS RTU products for pipe network pressure measurement are designed for this purpose. Because the pipe network pressure measurement technology is simple, there is no need to control, spread widely, so it is required that such GPRS RTU products have the characteristics of simple structure, reliable performance and low price.
1. Pipe network monitoring point Pipe network monitoring point: Each monitoring point collects data such as pressure and flow through the data acquisition module and connects to the GPRS transparent data transmission terminal through the RS232 (RS485) interface. Devices without a standard communication interface can also be used. Our company has RS6011G GPRS RTU with analog and digital acquisition capabilities. The embedded data processor is embedded in the GPRS transparent data transmission terminal. The data is processed, encapsulated and sent to the GSM network.
Ruishen RS6011G GPRS RTU product introduction (1), basic principle:
Through the RS-485 bus, the digital sensor (which can also use the analog output sensor) and Ruishen wireless intelligent measurement and control terminal as a whole, constitute a field monitoring unit. Ruichen wireless monitoring and control terminal built-in: CPU module, data storage module, control module, GPRS/CDMA data communication module. Field access to multiple analog, digital, relay signals, and other data, and then directly through the GPRS wireless module to connect the field data and remote control center, the real-time collection of data sent to the remote database server, and stored in the database. Through this system, even in remote locations away from the observation site, it is convenient to read and collect data on various environmental elements such as flow, pressure, etc., realizing the functions of remote monitoring and data sharing. In addition to remote data acquisition and real-time monitoring, the system can also implement remote cell phone alarms and remotely control field devices through the user's mobile phone.
(2) Features:
â—Ž equipped with a variety of interface resources: including analog signal acquisition, digital input, output, pulse signal input;
â—Ž Supports all user data interfaces of RS232/RS485, which can be connected to PLC and other devices;
â—Ž Integration of transmission and control, improving system reliability and reducing costs;
â—ŽUsing industrial-grade ultra-low power and high-performance embedded processor;
â—Ž user can program range conversion and alarm upper and lower limit settings;
â—Ž Built-in industrial clock, precise timing;
â—Ž automatic timing report and event trigger reporting function;
â—Ž built-in large-capacity FLASH memory, automatic data recording, support for historical data retrieval;
â—Ž Perfect communication protocol, configuration software support, users free development;
â—ŽOnboard industrial grade GPRS transmission module;
â—ŽProvide user setting software, open interface, convenient connection with group software and other software;
â—Ž industrial design, stable and reliable, durable;
2, monitoring center
The server applies to configure a fixed IP address and uses the dedicated line provided by the mobile communication company to connect to the GPRS network. Because the dedicated line can provide higher bandwidth, when the number of monitoring points in the pipe network increases, the center can meet the demand without expanding the capacity.
The monitoring center server receives the connection application from the GPRS network terminal and performs the authentication first. After the authentication passes, the received data is accepted and processed.
3, system function center control room is responsible for the entire system control and monitoring. With printer radio and so on.
Remote telemetry measures the status of each station, and monitors the pressure of each pressure measurement point to regulate the opening and closing of the pump of the water supply system; measurement and control can be performed by human intervention, and can also be performed according to the settings.
The data processing can store the working status information of each site of the system and perform statistical processing on the information to generate various report outputs.
The network connection system uses MODBUS RTU/ASCII protocol, which can be easily connected to other computer systems.
The alarm indication monitoring data volume has upper and lower limit alarm indication function.
System parameters input and configuration input system parameters, such as inspection cycle, control parameters, alarm limits, calculation formulas, system time, etc., and configure these parameters to form a complete system operation, control, statistics, display, print Parameter database. The entire system operates on this database.
The automatic inspection center control room automatically inspects n sites and the working conditions of pumping houses.
Manual acquisition can manually patrol N sites and obtain monitoring data.
Historical data printing Automatically print system operating data such as telemetry and remote control according to the system setting parameters.
The statistics of water supply data can realize the pressure on N pipelines and generate reports.
Remote diagnosis, remote maintenance, remote upgrade via the network, remote diagnosis of GPRS RTU, remote maintenance, remote upgrade.
Conclusion
This system takes the production process of waterworks as the background, and puts forward a set of PC-based automatic water supply computer monitoring system design scheme. The on-site commissioning proves that this scheme is feasible and feasible, which not only ensures the uninterrupted production of the water plant but also improves the management level of the water plant. The development time of the system is short, the cost is low, and the energy saving benefit is obvious. It is suitable for the technological transformation of water supply and dispatching in large and medium-sized cities.
The urban water supply dispatch monitoring system can monitor and control the remote on-site operating equipment to realize the data transmission of pipe network pressure, water flow, etc., and the control of the water output of various water plants so as to facilitate timely understanding and control of remote production and operation conditions. Failure rate, shorten repair time, reduce the number of water stops. The data collection terminal of each pipe network monitoring point can automatically collect real-time data such as pipeline pressure and water flow. The information is transmitted to the water company's dispatch center. The dispatch center can analyze the transmitted data to find out the location of the failure. When a remote fails, the problem can be solved in the shortest possible time.
At present, the data communication used in the tap water supply dispatch monitoring system can be simply divided into two categories: wired and wireless, among which the wired communication mainly includes the installation of optical cables, cables or leased telecommunication telephone lines, X.25, DDN, ADSL, etc. while the wireless Including ultra-short wave communications, spread spectrum communications, satellite communications, GSM SMS / GPRS communications.
In urban water supply dispatch monitoring systems, because of the wide distribution, number, and distance of individual monitoring points of pipeline networks, individual stations are also located in remote locations. Therefore, it is difficult and costly to set up optical cables (cables) to lease dedicated telephone lines to the telecommunications sector. Many telephone lines have to be applied, and some monitoring points are difficult to reach. In addition, it takes a long telephone dialing process when the telephone line is used, which is slow and the operating cost is high and it is not practical. In short, the monitoring system adopts wired communication, which has a long construction period, is difficult to work, and has high operating costs. It is inconvenient for large-scale use. In contrast, wireless communication is very flexible. It has less investment, short construction period, and maintenance. Simple, cost-effective advantages.
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 used only in some special fields due to its high communication cost. It is popularized; while the spread-spectrum communication technology has a high rate, it can only be transmitted within the range of sightlines, and its application is also limited. The adoption of ultra-short wave data transmission radio as the transmission channel has the advantages of flexible networking, easy expansion, easy maintenance, and low operating costs. However, since the system operates at 230 MHz and uses common indirect modulation digital radio stations, this results in the system being vulnerable to external interference. Low communication rate, high bit error rate, small amount of data transfer, and small signal coverage.
After a comparative analysis, we chose China Mobile's GPRS system as the data communication platform for the water supply dispatch monitoring system. At present, the GSM network has been built by the telecommunications sector for many years and its coverage has been continuously expanded. It has become a mature, stable and reliable communication network, especially the newly launched GPRS data service of China Mobile. The GSM/GPRS system provides a wide area wireless IP connection. Constructing tap water supply dispatch monitoring system on mobile communication company's GPRS service platform to realize wireless data transmission of pipe network monitoring point has the advantages of making full use of existing network, shortening construction period and reducing construction cost, and convenient installation and maintenance of equipment. .
system structure
In order to meet the scheduling and command of the production process, a reliable SCADA system is needed. It is generally composed of enterprise production dispatching command center, water plant, pipe network pressure measurement point, meter reading telemetry and so on. Its functions generally include: data acquisition control functions, data transmission functions, data display and analysis functions, alarm functions, storage, retrieval, query functions of historical data, report display and printing functions, remote control functions, and network functions.
The pipe network measuring point SCADA automation control system mainly monitors the decentralized pipe network measuring point site. The system adopts two-level control. The first level is the central control room of the SCADA system, and the second level is the remote measurement and control terminal GPRS RTU of the pipe network measuring point. The central control office is responsible for monitoring, management and control. The site GPRS RTU is responsible for the data collection of multiple pipe network measuring point sites, wireless transmission, and automatic control of pipe network measurement point pressure.
The dispatch center monitors the pipe network monitoring points in real time and directs the water output of each water plant. It is the system's information collection and control center. The dispatch center collects the data information of each site, and stores, analyzes, summarizes, or prints such information. Through data analysis, timely alarm information is given or a control command is sent to the site to control the operation of the site equipment so as to realize the scheduling and management of the entire system.
GPRS RTU (Remote Measurement and Control Terminal) is the basic component of the SCADA system. Acquisition, control and communication are the basic functions he has. For enterprises with distributed, distributed, and networked features, the establishment of a SAS/SCADA system is inseparable from the GPRS RTU products. The SCADA system in the urban water supply integrated automation system must have and is a very important function: to monitor the flow, pressure, and other changes in the water supply network throughout the city in real time and accurately. The GPRS RTU products for pipe network pressure measurement are designed for this purpose. Because the pipe network pressure measurement technology is simple, there is no need to control, spread widely, so it is required that such GPRS RTU products have the characteristics of simple structure, reliable performance and low price.
1. Pipe network monitoring point Pipe network monitoring point: Each monitoring point collects data such as pressure and flow through the data acquisition module and connects to the GPRS transparent data transmission terminal through the RS232 (RS485) interface. Devices without a standard communication interface can also be used. Our company has RS6011G GPRS RTU with analog and digital acquisition capabilities. The embedded data processor is embedded in the GPRS transparent data transmission terminal. The data is processed, encapsulated and sent to the GSM network.
Ruishen RS6011G GPRS RTU product introduction (1), basic principle:
Through the RS-485 bus, the digital sensor (which can also use the analog output sensor) and Ruishen wireless intelligent measurement and control terminal as a whole, constitute a field monitoring unit. Ruichen wireless monitoring and control terminal built-in: CPU module, data storage module, control module, GPRS/CDMA data communication module. Field access to multiple analog, digital, relay signals, and other data, and then directly through the GPRS wireless module to connect the field data and remote control center, the real-time collection of data sent to the remote database server, and stored in the database. Through this system, even in remote locations away from the observation site, it is convenient to read and collect data on various environmental elements such as flow, pressure, etc., realizing the functions of remote monitoring and data sharing. In addition to remote data acquisition and real-time monitoring, the system can also implement remote cell phone alarms and remotely control field devices through the user's mobile phone.
(2) Features:
â—Ž equipped with a variety of interface resources: including analog signal acquisition, digital input, output, pulse signal input;
â—Ž Supports all user data interfaces of RS232/RS485, which can be connected to PLC and other devices;
â—Ž Integration of transmission and control, improving system reliability and reducing costs;
â—ŽUsing industrial-grade ultra-low power and high-performance embedded processor;
â—Ž user can program range conversion and alarm upper and lower limit settings;
â—Ž Built-in industrial clock, precise timing;
â—Ž automatic timing report and event trigger reporting function;
â—Ž built-in large-capacity FLASH memory, automatic data recording, support for historical data retrieval;
â—Ž Perfect communication protocol, configuration software support, users free development;
â—ŽOnboard industrial grade GPRS transmission module;
â—ŽProvide user setting software, open interface, convenient connection with group software and other software;
â—Ž industrial design, stable and reliable, durable;
2, monitoring center
The server applies to configure a fixed IP address and uses the dedicated line provided by the mobile communication company to connect to the GPRS network. Because the dedicated line can provide higher bandwidth, when the number of monitoring points in the pipe network increases, the center can meet the demand without expanding the capacity.
The monitoring center server receives the connection application from the GPRS network terminal and performs the authentication first. After the authentication passes, the received data is accepted and processed.
3, system function center control room is responsible for the entire system control and monitoring. With printer radio and so on.
Remote telemetry measures the status of each station, and monitors the pressure of each pressure measurement point to regulate the opening and closing of the pump of the water supply system; measurement and control can be performed by human intervention, and can also be performed according to the settings.
The data processing can store the working status information of each site of the system and perform statistical processing on the information to generate various report outputs.
The network connection system uses MODBUS RTU/ASCII protocol, which can be easily connected to other computer systems.
The alarm indication monitoring data volume has upper and lower limit alarm indication function.
System parameters input and configuration input system parameters, such as inspection cycle, control parameters, alarm limits, calculation formulas, system time, etc., and configure these parameters to form a complete system operation, control, statistics, display, print Parameter database. The entire system operates on this database.
The automatic inspection center control room automatically inspects n sites and the working conditions of pumping houses.
Manual acquisition can manually patrol N sites and obtain monitoring data.
Historical data printing Automatically print system operating data such as telemetry and remote control according to the system setting parameters.
The statistics of water supply data can realize the pressure on N pipelines and generate reports.
Remote diagnosis, remote maintenance, remote upgrade via the network, remote diagnosis of GPRS RTU, remote maintenance, remote upgrade.
Conclusion
This system takes the production process of waterworks as the background, and puts forward a set of PC-based automatic water supply computer monitoring system design scheme. The on-site commissioning proves that this scheme is feasible and feasible, which not only ensures the uninterrupted production of the water plant but also improves the management level of the water plant. The development time of the system is short, the cost is low, and the energy saving benefit is obvious. It is suitable for the technological transformation of water supply and dispatching in large and medium-sized cities.