Ultrasonic flow detection circuit

Abstract

The invention discloses an ultrasonic flow detection circuit. The ultrasonic flow detection circuit consists of an ultrasonic source signal generation circuit, a signal transmitting and receiving circuit, a detection circuit, a phase detection circuit, a phase-to-voltage conversion circuit and a 12-bit analog-to-digital (AD) module of a micro processor. During measurement, the ultrasonic source signal generation circuit generates a 1MHZ signal and keeps the whole fair current and adverse current measurement process; an ultrasonic transducer receives an ultrasonic signal and filters out noise and an interference signal through the detection circuit; the signal is compared with a reference signal through the phase detection circuit so that a phase difference is generated; the phase-to-voltage conversion circuit converts a measured signal into a voltage signal; and a voltage value is measured through the high-precision AD conversion of the micro processor. As the fair current transmission speed and the adverse current transmission speed of the ultrasonic are different, the finally measured voltage amplitudes are different; a time difference can be obtained from the voltage different through conversion; and the flow can be calculated according to a corresponding formula.

Description

(1) Technical field [0001] The invention relates to the field of flow measurement, and in particular discloses an ultrasonic flow detection circuit. (2) Background technology [0002] Currently, ultrasound is used for flow velocity measurement of fluids with many advantages. Compared with the traditional mechanical flow meter, the electromagnetic flow meter has high measurement accuracy, strong adaptability to pipe diameter, non-contact fluid, easy to use, easy to digital management and so on. The principle of ultrasonic measurement of fluid flow is: when the ultrasonic wave propagates in the flowing fluid, it carries the information of the fluid flow velocity, so the flow velocity of the fluid can be detected by the received ultrasonic wave, and then converted into flow rate. The most widely used method is to use a pair of ultrasonic transducers to send and receive ultrasonic waves alternately (or at the same time), to measure the flow velocity of the fluid indirectly by o...

AI Technical Summary

Problems solved by technology

At present, most manufacturers use the German ACAM patented product TDC-GP2 time interval measurement chip to measure the flow through the direct time difference. In this way, if the signal transmission and reception time control is not accurate or the circuit design accuracy is not high enough, random time measurement will occur. The error affects the measurement accuracy, especially when the household has a small diameter and small flow measurement, the stability is very poor, and the cost is high. In order to reduce the cost and improve the measurement accuracy, our company has developed an ultrasonic flow detection circuit.

Images