CampbellScientific, Inc., real-time tools dedicated to helpingmonitor water resources
St.Johns River Water Management District Thegoal of the Department of Resource Management is to ensure thesustain-able use and protection of water resources for the benefitof the people of the St. Johns River Water Management District(SJRWMD) and the state of Florida. Thedepartment has six divisions: Groundwater Programs, Hydrologic DataServices (HDS), Permit Data Services (PDS), Resource ManagementSupport and Environmental Management, Water Supply Planning, andWater Use Regulation. HDScollects, processes, manages, and disseminates hydrologic andmeteorological data used for water use planning and management,environmental protection and restoration, and flood controlpurposes. The division operates andmaintains more than 1,000 monitoring stations throughout thedistrict. Italso processes data from approximately 200 additional sitescollected by county and municipal agencies through mutual agreementor by the U.S. Geological Survey under contract to thedistrict. Morethan 7 million measurements are collected, verified, processed, andstored by HDS staff each year. The data is disseminated todistrict staff and the public upon request. HDS also compiles thedistrict’s Hydrologic Conditions Report, posted on the district’sWeb site each month. SJRWMD has set up a data acquisition network using CampbellScientific equipment to monitor rainfall and water level forbaseline data, water management, and flood control response andwarnings. The network uses over 370 CampbellScientific dataloggers interrogated by four base stations thatretrieve data to a central Hydstra database. Thedistrict has three UHF licensed frequencies. The districtheadquarters in Palatka has two RF base stations. Each base station uses its ownfrequency—combined they poll 208 stations. There are remote basestations at Apopka (68 sites) and Palm Bay (98 sites) to poll theremaining stations. Abroadcast Time Domain Multiple Access (TDMA) technique has beenused by Campbell Scientific since the early 1990s for networksrequiring high data throughput. The RF bandwidth is tightlycontrolled and optimized to move data from many data-loggers asefficiently as possible. This method allows forstand-alone repeaters, and also allows datalogger measurement sitesto act as repeaters. The technologyfocuses on measuring, storing, and transmitting accuratetime-stamped data. LoggerNet software rap-idly gathersreal-time data as the highestpriority, but ininactive periods collects any outstanding time-stamped historicaldata allowing any “holes” in the data to be filled. Additionally, maintenance functions such as new program download, operating system download to the datalogger, clock synchronization, and changes to settings are performed during inactive periods. Thedata is transferred in a master/slave configuration. At each poll interval, the RF base station (master radio) broadcasts a message to all dataloggers (slaves) that can be reached without using a repeater. Upon receiving the broadcast, each datalogger sends its data at the pre-defined time; time windows can be less than one second. When sites are accessed through a repeater, the repeater sends out a broadcast to its remotes that in turn respond with their data at predefined times. The data is placed in packets and sent to the server at the RF base station. There can be any number of repeaters; sites at St Johns are up to four deep in the network. SJRWMD was pleased with the network performance during thesummer Hurricane season of 2004. The RF system worked flawlessly. There were problems with the Intranet provider, causing links to the two remote LoggerNet–RF base stations to be lost. A redundancy has been designed into 16 of the most critical sites using CR510s and digital cell phones to provide redundant access to the data. Theoriginal contract required Campbell Scientific to install the first20 sites and prove the technology. After training, the district installed the remainder of the sites. One hundred additional RF telemetry sites are planned for 2006. 
项目概况 应用类型：水资源管理 位置：St. Johns River WaterManagement District, Florida USA 承包商：SJRWMD 数据采集器：Campbell ScientificCR510's (260), CR10X's (55), CR10's(55) 通讯：RF310，RF310M（374个点），数字移动电话(16个点) 测量/计算参数：水位，降水 |