Research On Runoff Current Velocity Measuring System Of Virtual Instrument

In the soil erosion research, the slope face runoff speed of flow is studies the slope face soil erosion rule the important parameter. Also it is the soil erosion dynamic monitor network foundation data. At present, regardless of is in the field test observation runoff plot or in the room the manual simulation rains in the experiment, the slope face runoff speed of flow survey always uses artificial or half manual measuring technique, is unable to realize dynamically, is continual real-time, surveys. Therefore studies one kind of survey runoff speed of flow real-time, the dynamic measurement system, has the vital scientific significance and the practical value.This research using the self-made conductance sensor took signal gathering the sensor, has established based on the hypothesized instrument technology runoff rate of flow measurement system. Its research main content and result as follows:1. This test has carried on the theoretical analysis correlations rate of flow measurement principle, has established based on the hypothesized instrument technology runoff speed of flow real-time measurement system theoretical model;2. The research gathered the fluent silt mobile noise signal the electric conductance type sensor to carry on the design, mainly included the sensor material quality, the shape, the size, recuperated the electric circuit and so on;3. The correlations rate of flow measurement system has used the differential motion enlargement electric circuit below, it has the prominent characteristic : First, retained the correlation method to measure the fast principle the merit, reduced the correlation method to the hardware electric circuit, the data acquisition electric circuit symmetry has requested the high shortcoming, caused the noise to withdraw the electric circuit the complexity to reduce, enhanced the system reliability, the ability of contradict disturb. Next, utilizes the symmetrical examination electric circuit, has counterbalanced two sensors the external interference influence, in the certain degree eliminated the electric conductance type sensor initial error. Because only withdraws with two phase currents fluids related mobile noise, recuperates the electric circuit to have increases greatly, thus may enhance the system the sensitivity;4. This system uses the correlation algorithm, compiled the runoff speed of flow test system survey procedure with graphics programming language Lab VIEW, and has established based on the hypothesized instrument technology runoff rate of flow measurement system.Through the experiment obtains the following conclusion :1. Through demarcates the experiment, this test system surveys the runoff speed of flow with the correlation method is feasible;2. The self-made electric conductance type sensors in survey scope internal energy accurate gathering runoff mobile noise signal;3. The runoff speeds of flow measuring instrument survey scope is 0 ~ 250 kg/m3, the speed of flow measuring error is smaller than 5% ;4. This virtual instrument may real-time, on-line survey runoff speed of flow.