Research And Implementation Of A Multi-parameter Online Water Quality Sensor

Water quality refers to water and impurities in water together constitute water’s physical, chemical biological and integrated nature. The water quality characteristics determine the difference of water quality sensor and conventional sensor. It has diversity and interdisciplinary. The man-made pollution is increasingly serious. Today, water and waste released by industrial production, pesticides and fertilizers used by agricultural production, a lot of sewage and garbage are drained into water. Water feature is much more complex than ever. Therefore, the water monitoring sensor is even more complex. In order to fit the increasing demands of the water rescource management, a new noval multi-parameter online water quality sensor is presented in this paper.In water quality sensor:three key issures are system reliability, low power consumption and self-maintenance. Perspectively, reliability problem of water quality sensor is closely relative to hardware, software, system structure design as well as its manufacture process. So perfect comes from detailed precision.The main contents and contributions are as follow:Firstly, To reduce energy consumption, a functional method, only working elements are power supplied, while turn off others which only work in cycle.Secondly, To realize self clean the sensors’ability, a pump driving recurrence washing structure is studied and implemented and a ultrasonic frequency pulse sweep is pretended against the microorganism hanging on the sensors.Thirdly, five of parameters of water quality sensors are studied in detail. They are pH, dissolved oxygen, conductivity,water level, water temperature. Creative measurement methods are studied, such as electronic potential is used for pH measurement, electronic current is used for dissolved oxygen measurement, symmetric pulse method is used for conductivity detecting, isolation diaphragm pressure sensor is used for water level measurement.With the achievement above, a systematically designed multi parameter sensor is developed and described in the paper. It is composed of amould shell in a compact, sealed, cylindrical, segmented shape in which five modules are integrated, they are main control module, pH measurement module, dissolved oxygen measurement module, conductivity measurement module, water level and temperature measuring module as well as the system designed for self maintenance. Each module has an independent MCU. All the modules are connected via RS485bus.It is known, the test and study of any sensor at the simulated extreme experimental environments are important, the test and demonstration of the sensor’power, accurancy, temperature stability for each integrated sensor are also described in chapter? A compact5parameter water quality transducer has been installed in Taiping Hydraulic Station, Chonghua City, Guangdong Province since July,2011. Analysis and observation of the transducer is indicated in chapter? The transducer works well until present time.