Research On Communication And Cotrol System In Unattended Hydrographic Station

Monitoring of hydrological information is a very important andmeaningful work, timely and accurate hydrographic data is the key to effectiveimplementation of forecasting, flood control and disaster mitigation. Withtechnological progress and economic development, increasing labor costs,hydrological information monitoring toward the development of intelligentunattended. Velocity and discharge cannot be measured directly in unattendedhydrometric stations, a new type of unattended hydrometric station is proposedin this paper. It can not only directly measure stage data like other unattendedhydrometric station, but also directly measure velocity data and finish thedischarge measurement by width-integrating method.According to the functional requirements and working conditionscharacteristics of unattended hydrologic station, the measurement of stage,velocity and discharge, communication methods and control system about theunattended hydrometric station are researched in this paper，and monitoringterminal controllers and special electrical power system for the unattendedhydrometric station are developed.Comprehensive comparison of characteristics of existing variouscommunication technologies, combined with the demand of unattendedhydrometric station, GPRS network is selected to realize remotecommunication, local communication of unattended hydrometric station isdone by ZigBee wireless network，and the appropriate communication moduleof industrial is chosen to finish communication tasks. Comparing the performance characteristics of a variety of microprocessor chip，and combinedwith the demand of unattended hydrometric station， monitoring terminalcontroller with a wealth of input/output interfaces, communication interfacesand other resources is developed which master control chip isSMT32F103ZET6chip that is based on kernel Cortex-M3. The solar panelsand batteries are selected as power source system for unattended hydrometricstations which work in the field.Measurement of hydrological information: radar stage gauge is selectedto measure the stage; radar current-meter is chosen to measure velocity;discharge measurement is accomplished by width-integrating method. Amobile radar stage measures the velocity of the velocity-measuring verticalverticals along the cable across the River, and combined with the depthinformation and the river cross-section calculates the discharge measurement.According to the hydrological function of monitoring system and workingmechanism, the communication protocols and data formats of hydrologicmonitoring system is set up, and software program flowchart and part sourcecode of the program’s acquisition and processing is presented which is aboutthe key hydrological information.ZigBee and GPRS networks are selected for information short-distanceand long-distance transmission of the unattended hydrometric stationtransmission，the high performance master control chip is selected to managethe equipment of monitoring site. The unattended hydrometric station canmeet the requirements of hydrological monitoring with low cost.