Design of low-power consumption ultrasonic open channel flow meter

The measurement principle of ultrasonic sensor in an open channel flow meter is introduced. A new low-power consumption ultrasonic flow meter, which is based on the MCU of MSP430, is designed for the flowrate measurement of open channels. The measurement characteristics of the Parshall flume are analyzed. The experimental data agree with the relationship between the flowrate and the liquid level in Parshall flume. In order to reduce the power consumption, the running time of CPU is minimized. The algorithm in the program is optimized to avoid floating-point calculation. The operating mode of MSP430 is set to be reasonable. Through the flow calibration experiment, the relevant flowrate measurement model is established. The experiments indicate that electric current is 100 uA at working state and that is 10 uA at sleeping state. The results show that the error of the instantaneous flow is less than 1.654% and the error of the accumulated flow is less than 1%.