Application scheme of GPRS data acquisition system in water industry

　　With the development of China's economy and society, new requirements are constantly put forward for the information construction of the industry, and higher and higher requirements are put forward for the R & D and application of observation means and methods and monitoring technology in the water industry; The rapid development of modern electronic technology, sensing technology, communication technology and computer technology has also promoted the development of monitoring technology automation in water industry. In this regard, Yiwei is at the front of the information construction of the water industry.

　　1、 Application of monitoring automation technology in water industry

　　1. Scope and content of water industry monitoring:

　　The monitoring of water industry is the integration of sensor technology and acquisition, storage, transmission and processing technology.

　　Monitoring scope: rivers, lakes, reservoirs, channels and groundwater.

　　Monitoring contents: water level, flow, flow rate, pressure and water quality, etc.

　　2. Collection and transmission of water level

　　The water level sensors used for automatic monitoring mainly include float water level gauge, pressure water level gauge, electronic water gauge and ultrasonic water level gauge. These parameters can be directly monitored by the PLC. The monitoring of groundwater level is the same as that of surface water. At present, the data communication between the Provincial Hydrological monitoring station and each collection point mainly adopts manual transcription or PSTN telephone line transmission. When using telephone line to transmit data, the speed is slow and the cost is high because of the need to wait for each dial. At the same time, due to the wide distribution range, large number and long distance of monitoring points, and individual points are also located in remote areas, many telephone lines need to be applied, and some monitoring points are difficult to reach by wired lines.

　　GPRS has the characteristics of high speed and low cost, and its transmission speed can reach 171.2kb/s. Compared with wired communication mode, GPRS wireless communication mode is very flexible. It has the advantages of flexible networking, easy expansion, low operation cost, simple maintenance and high cost performance. Therefore, GPRS wireless transmission mode is being considered to solve the problem of real-time transmission of pollution source monitoring data.

　　2、 Solution introduction:

　　(1) System structure

　　(2) Connection mode between GPRS wireless network and center software:

　　A. Public network scheme:

　　The center uses a server group as the center to receive. The center uses ADSL and other Internet public networks to connect, and uses public network fixed IP or public network dynamic IP + DNS resolution services. This scheme first applies for ADSL and other broadband services from Internet operators.

　　1) Central public network fixed IP: the monitoring point directly initiates a connection to the central fixed IP. The operation is reliable and stable. This scheme is recommended. (of course, fixed IP costs are relatively expensive, depending on the customer's financial resources)

　　2) Central public network dynamic IP + DNS resolution service: most IPS are dynamic and relatively cheap. The customer first contacts the DNS service provider to open the dynamic domain name. The website of the dynamic domain name resolution software is as follows: (you can apply for a free secondary domain name first) 88ip name resolution http://www.juyingele.com.cn

　　The monitoring point first connects to the DNS server by domain name addressing, and then the DNS server finds the dynamic IP of the central public network and establishes the connection. This method can greatly save the cost of public network fixed IP, but the stability is subject to the stability of DNS server, so we should find a reliable DNS service provider.

　　As shown in the above figure, the hydrological remote measurement and control dispatching system is composed of dispatching center, wireless GPRS network and remote terminal unit (GPRS wireless transmission equipment, PLC):

　　1. Remote terminal unit

　　The remote terminal unit is distributed in various remote telemetry points, which is mainly composed of GPRS module, power supply, antenna, PLC and various water industry sensors.

　　PLC is connected with the field instrument (sensor) to collect, process and store the switching value and analog signal of the field instrument (sensor), transmit the data to the dispatching center through GPRS module, and receive and execute the command of the dispatching center.

　　PLC: select brands according to customer requirements, such as LG, Siemens, Mitsubishi, Omron, etc.

　　Wireless transmission equipment: jy-rtu4100 GPRS DTU transparent wireless data transmission terminal, which is connected with each PLC of the equipment acquisition point of the water industry through RS232 / RS485 / TTL, and transmits the data to the dispatching center through GPRS network.

　　2. Dispatching center

　　The computer processing system of dispatching center is an open real-time application system, which realizes all data processing. The functions of the center include: data sending and receiving management, site management, water industry data management and system management.

　　Data telemetry function: regular patrol test, manual patrol test, random sampling test and group call test.

　　Remote control function: control the on / off state and remote signaling switch state of RTU switching value output point.

　　Parameter status management function: set and modify the upper and lower limits of each measurement data and communication parameters.

　　Online configuration function: adding data acquisition points and other parameters can be completed through configuration definition.

　　Database management function: build a database for the measured data, process the data, query the historical data and print the report.

　　Data display function: it can display all kinds of measured data, remote signaling switch status, various system graphics, etc. it has graphics function to simulate and display pipe network diagram, water plant process flow diagram, etc. Data entry and statistics of emergency repair, water cut-off and pipe network flushing.

　　Data sharing function: provide a web site that enables any workstation of the company's broadband intranet to log in and view the real-time data of all monitoring points and the stored historical data of any time period only through the web browser. The web site controls the user through user identity authentication and authorization. The user can access the real-time monitoring data of those monitoring points and the stored historical data of any time period. The system administrator of the dispatching center can add and delete accessible users and authorize users with different permissions. The web site shall be able to connect to the company's unified platform through hyperlink.

　　3、 Product introduction

　　1、 Provide equipment status indicator to facilitate equipment maintenance;

　　2、 Wide voltage power supply range: 5v-30v;

　　3、 With RS232 and RS485;

　　4、 Built in high-capacity SPI flash (1mbit-64mbit optional) to save data locally for a long time (customized);

　　5、 4 analog inputs, acquisition accuracy: 12bit

　　6、 The transmission supports a variety of protocols, and our company's self-defined protocol and Modbus Protocol (ASCII, RTU, Modbus TCP) are perfectly supported;

　　7、 Data transmission adopts GSM module, which can realize the following functions:

　　1) GPRS disconnection automatic reconnection;

　　2) Up to 6 central servers can be connected at the same time as required;

　　3) Support the addressing mode of fixed IP, domain name resolution and APN private network;

　　4) Support TCP, UDP, PPP, ICMP, DNS, FTP and other protocols;

　　5) The number of supported nodes is theoretically unlimited as long as the server resources allow;

　　6) Reduce the cost of wiring and the trouble of construction;

　　7) Support SMS data transmission and SMS parameter configuration;

　　8) Support phone and SMS wake-up function;

　　8、 Support special software for local and remote parameter configuration and maintenance;

　　9、 Support local and remote firmware upgrade;

　　The temperature test report is also available: from - 45 degrees to 85 degrees: temperature test communication report of remote measurement and control terminal (RTU)