Research On Photoelectric Low Power Consumption Measurement System For Turbine Flow Measurement

Accurate flow measurement is an important prerequisite for medical,energy,petrochemical and other industrial sectors.As the turbine flowmeter has the advantages of high precision,good reproducibility and good stability,it has become an important part of the flow measuring instrument.With the development of single-chip technology,ultra-low consumption microcontroller technology combines with traditional turbine flow meters,so that the new turbine flowmeter can achieve extremely low power consumption under the premise of satisfying high-precision measurement,meet long-term use of battery power supply.Based on the principle of velocity turbine flow measurement,this thesis proposes a novel photoelectric reflection sensor measurement method.By alternately and instantaneously driving the dual light-emitting diodes,it satisfies the requirement of using photoelectric pulses for flow measurement.The photoelectric measurement method greatly reduces the demand for power consumption.The specific research content is as follows:First,on the basis of introducing the measurement principle of velocity flow meters,the main problems of magnetic turbine flowmeters that are poor in anti-electromagnetic interference and difficult to drive with small flow are analyzed,and the photoelectric reflection type low power consumption based on alternate instantaneous drive is proposed.Flow measurement method.On the basis of the overall scheme design,the working process is described in detail.Second,the infrared measurement module circuit such as the corresponding infrared transmission circuit,an infrared receiving circuit,and signal amplifying circuit is designed according to the rotation instantaneous driving idea,and the conversion and sampling of the photoelectric signal are realized.And the components in the circuit are strictly selected to achieve low power consumption as much as possible under the premise of satisfying the measurement accuracy requirements.Third,according to the layout of the photoelectric cell,the signal driving mode and the characteristics of the reflective turntable,the counting logic algorithm software design is carried out.Utilize the multiple low power consumption modes of MSP430single-chip microcomputer and the function of timer interrupt wake-up,design the corresponding program initialization scheme,pulse counting logic and driving frequency switching algorithm,etc.,to meet the flow measurement basis,make the power consumption of the measurement system as low as possible.Finally,the measurement system was tested experimentally.First,the relationship between the distance between the reflective turntable and the photoelectric cell and the received signal strength was tested,and the appropriate distance point was found.Then the accuracy of the photoelectric pulse metering turbine revolutions was tested,and the measurement error was within 1 circle,and the test results met the requirements of high-precision measurement.Then measure the rotation angle of the reflective turntable corresponding to each change of the photoelectric pulse count value,and calculate the number of sampling points of the minimum periodic pulse signal to determine the range of the measurement system.The average current of the flow measurement system is measured through software simulation and experiment.The simulation and measurement results show that the average power consumption of this photoelectric flow measurement system is less than50μw when the 64 Hz drive signal is used,which meets the design requirements of battery power supply.