Study On Field Measure-Control Unit And Its Network For Water Measurement

The increasing water crisis in our country has gradually impeded economic development and affected the daily life of people. In the countryside, the lack of accurate accounting and good records results in waste of water. In order to measure water usage in the plain irrigation region, economic and flexible flow measure method should be chosen at the prerequisite of making good use of exiting water works. Considering the reality that the irrigation devices are usually various and the exiting open-channel flow meters are costly and inflexible, the chosen field unit should be general and worth.In the irrigation the water works are remote and scattered, therefore means of signals communication and network structures must be taken into account in the water measurement system.By analyzing existing flow measurement methods, several economic methods which are suitable to online meter and measure flow in the plain irrigation are chosen. The principle of flow measurement is also presented. Based on general PC-BASED programmable controller, the general and flexible measure-control field unit is developed, which has specialty characteristics and is suitable for different water measuring devices. Data sampling, flow calculation and controlling water works are also realized. Three feasible measuring and controlling schemes: gate, "pump-gate", "gate-flume" are mentioned, and the precision of major sensors are requested. Network designs suitable for the irrigation region are mentioned by analyzing existing network structure and means of signals communication. A typical example concerned with the network design of water measurement is presented, which manage the water works including pump stations, gates and flumes in Punan irrigation, Shanghai.