Available online at www.sciencedirect.com
Procedia Engineering
Procedia Engineering 00 (2011) 000–000 Procedia Engineering 28 (2012) 840 – 843
www.elsevier.com/locate/procedia
2012 International Conference on Modern Hydraulic Engineering
Water Quality Automatic Monitoring System Based on GPRS Data Communications WEI Dehuaa, LIU Pana, LU Bob, GUO Zengc, a* a
College of Hydropower, Hebei University of Engineering, Handan 056021, China; b Water Investigation Design Institute of Dezhou, Dezhou 253000, China; c Handan Running Water Company, Handan 056032, China;
Abstract In this paper, the water quality automatic monitoring system is discussed based on General Packet Radio Service (GPRS) platform, and the system is matched with the multi-parameter water quality monitor. The composition and operation principle of the system have been introduced. GPRS communication module connects with the multiparameter water quality monitor through the RS232. The communication module can receive instructions of the system and send the data which has been collected by the multi-parameter water quality monitor to the monitor centre. This system has stable performance, convenient to reduce operation cost, which has obtained good effect in practical application.
© 2012 Published by Elsevier Ltd. Selection and/or peer-review under responsibility of Society for Resources, © 2011 Published by Elsevier Open Ltd.access under CC BY-NC-ND license. Environment and Engineering Keywords: Water Quality; Real-time Monitoring; Multi-sensor Fusion; Communication; GPRS
1. Introduction Water quality monitoring is used to monitor and determine the type of water pollution, the concentration of various water pollutants and the changing tendency. It is an important means of water resources management and water environment protection. The source, the type, and the range of pollution can be discovered in time with the effectively monitoring on water pollution, so that the appropriate contingency plans can be determined, which has a good effect on human health and the safety[1].
* Corresponding author: WEI Dehua. Tel.: +86-0310-3123700 E-mail address:
[email protected]
1877-7058 © 2012 Published by Elsevier Ltd. Selection and/or peer-review under responsibility of Society for Resources, Environment and Engineering Open access under CC BY-NC-ND license. doi:10.1016/j.proeng.2012.01.820
841
WEIAuthor Dehuaname et al.//Procedia Procedia Engineering Engineering 00 28 (2011) (2012) 000–000 840 – 843
2
The real-time data can be continuously measured and recorded by the water quality automatic monitoring system. Since the monitoring points are dispersed and they are far away from the monitoring centre, the special wireless data communication system is not needed to establish when transmitting the water quality information to the relevant departments, unless there are special requirements for the data. Generally, the public net is applied to finish the data transmission which is economic and reliable. Especially in some systems, for example, the system with long distance, of which environment is very poor, and its data collection points are scattered [2]. 2. System components The structure of the water quality automatic monitoring system includes two parts, one is the water quality collection system and the other is the monitoring centre system. The system components are showed in Figure 1. Data acquisition system
Multi-parameter water quality monitor
RS232
Data collection sending terminal
Monitoring centre
GPRS
Database Server Internet
Router
SOHO
To MIS
Fig.1. The structure of the system diagram
2.1. Water quality data acquisition system Water quality acquisition system includes multi-parameter water quality monitor and GPRS module. The multi-parameter water quality transducer can convert the water quality information into analog signals. The analog signals are then sent to the data collection instrument, which can make A/D converting and the data can be saved. Multi-parameter water quality transducer connects to the GPRS module through RS232, thus the transducer can receive the command from the control centre and upload data. 2.1.1. Multi-parameter water quality monitor According to the demand and industrial standard, this system has some monitoring items, for example, water temperature, PH, conductivity, turbidity, DO, nitrogen, helium, ORP, nitrate, blue-green algae, etc. In order to reflect comprehensively the water quality conditions and the changing trends of the water quality in time, a multi-parameter water quality monitor can be used in the system. 6600 multi-parameter water quality monitor has adopted the multi-sensor fusion technology, which installs several sensors together. The transformation data is collected by the monitor and then the data is exported through RS232, which can be connected with the GPRS module directly [3]. 2.1.2. GPRS communication module GPRS communication module adopts H7210 GPRS DTU which uses module integration design. With PPP, TCP / IP, DDP and other agreements embed the GPRS intra-module module, the design could be
842
WEI Dehua al. / Procedia Engineering 28 (2012) 840 – 843 Author name / et Procedia Engineering 00 (2011) 000–000
simple. The dongle circuit is used in the external module. The circuit can monitor the running state of the module in real-time to ensure the module runs reliably and stably. Each of the monitoring points requires configuring a GPRS terminal module and is allocated a SIM card with the GPRS function when the network is built. The central station requires a fixed IP address and it also need to be installed a RADIUS authentication software. A wireless wide area network has been established after the monitoring points connecting with the central station. The central station can access the monitoring points to IP address which could realize data transparent transmission. After the SIM card being inserted the communication module, it is needed to set the parameters for data transfer unit. For example, the parameters includes transmission rate, data bits, communication parameters, the parity, mobile centre, service code, the access point name, DTU identification, local communications port, the IP address of the data service centre, etc[4]. 2.2. Monitoring center system The real-time monitoring server consists of a PC installed with software of data control. The PC has a fixed IP internet connection. The real-time monitoring server is used to control the system, data storage, data analysis and communication. 3. Development of monitoring software system The water quality acquisition system can transmit the data to the monitoring centre system through the GPRS network and Internet according to the specific statute [5]. Then the data is analyzed and processed in the system. GPRS DTU can send the data message using the UDP mode. Usually, virtual serial port connection can be used, unless an apply style is wanted to change for the original system software. The collection points of network are easy to extend and the size of the network is almost limitless in this way, thus this approach can be used in the area covered by China Mobile's entire network. It is easy to form a network which crosses the province and a region, because the SNMP protocol can be used to achieve the centralized management of all network devices. 3.1. The software system of data acquisition Water quality automatic monitoring system adopts operation type of long term online and unattended type monitoring, and the interval of the data collection is set to one hour. The water quality monitor with multi-parameters has been put into the water, and it is usually in a dormant state. The monitoring centre can send wake-up command to the multi-parameter water quality monitor and wake it up through the GPRS DTU when the collection system starts to take sample. Then the monitoring centre sends collect command to the multi-parameter water quality monitor again. The multi-parameter water quality monitor starts to work and converts the collected data into the formatted datagram. The multi-parameter water quality monitor sends the datagram to the GPRS DTU, and then the datagram could be sent to the monitoring centre by the DTU. The monitoring center could send the sleep command once again to make the water quality monitor enter sleep state when the monitoring center receives the complete datagram. When the monitoring station is power cut or GPRS communication is error, the datagram can not be promptly sent to the monitoring center, and the water quality monitor has auto-storage function. The data can be extracted manually by the staff when the monitor is in maintenance to ensure the continuity of the data. The process of collecting data is shown in Figure 2. 3.2. The software system of control center
3
4
WEIAuthor Dehuaname et al.//Procedia Procedia Engineering Engineering 00 28 (2011) (2012) 000–000 840 – 843
The control centre of the software system mainly includes GPRS data receiving / sending module, data output module and data statistic analysis module, etc. The computers of the control centre system connect to the Internet through static IP. So the data reception module could accept all the data which are outputted by water acquisition subsystem through the Internet, and the data reception module can analysis the data packets and can store the data into the database. The data can be analyzed and summarized by the data statistic analysis module. The data statistic analysis module can also predict the trend of the water quality. Waiting for sampling Wake-up command Collecting command Stay and monitor
Receiving data
Dormancy command
Waking up the data acquisition instrument Collecting data Formatting data Sending data Dormancy
Fig. 2. The process of collecting data flow diagram
4. Conclusion The system has been successfully applied to water quality monitoring of a water supply system in a northern city. It is proved from practice that the system is reliable, easy to expand and update, and has a low running cost. The system can achieve water quality data collection and transmission in real-time through GPRS network. The GPRS communication technology could also be used in hydrological forecasting, soil moisture remote sensing, remote monitoring of the river dam, irrigation water monitoring system, etc. The working state of the system not only could be monitored in the control centre, but also be monitored through the Internet at home, so that the monitoring situations could be held anywhere or anytime. This system has a broad application prospect in the hydraulic territory. References [1] JIANG Jianhu, ZHANG Zhenjiang. Water Quality Monitoring System Based on GPRS and GPS. J Instrumentation and Measurement; 2006, 25: 66 [2] XU Xiaodan, BAI Zhifeng. Application of GPRS in Water Information System. J Systems & Solutions; 2009, 6: 56 [3] Handan Lofty Technology Development Company Limited. Operation Instruction of Water Quality Automatic Online Monitoring System; 2009, p. 28—27 [4] HAN Binjie.GPRS Principle and Network Optimization[M]. China Machine Press, 2003. [5] CHEN Jun, SHENG Zhanshi, CHEN Zhaozhang, SUN Jun, ZHANG Bing. Design of Automated Monitoring System of Water Quality Based on GPRS. J Transducer and Microsystem Technologies; 2009, 28: 78
843
