Development Of Ultrasonic Flow Meter Based On Embedded System

Recently, water resource is becoming more and more rare, which requires that the measure precision of water flow should be rather high. Whether in industrial or in living, the measure to water requires a high-precision, handy-operation, low-price' measure instrument. Especially, the measure of some causticity liquid is very difficult using the old flow meter. But the ultrasonic flow meter can solve this problem because of using the non-touch method.Ultrasonic can carry the information of the liquid when it transits the flowing liquid. According to this theory , ultrasonic flow meter can measure the velocity of flow through the simple, reliable signal processing method. Comparing with the traditional flow meter, ultrasonic flow meter has many advantages such as low-price, simple fixing, not changing the liquid' flow state, no additional resistance etc. However, it is not perfect. So, we need study it any more in order to improve it.This article introduces ultrasonic flow meter' measure theory, configuration of hardware and the design of the software. In order to improve the measure precision and the reliability, we use new-style chip and new theory. The using of ARM makes the system have more rapid running velocity and more data-processing ability. Using the Digital phase detector can improve the measure precision of time strongly. The process of digital signal include routine filter circuit and Automatic Gain Control Circuit. Digital phase detector and signal selecting circuit are integrated the CPLD chip which produced by Xilinx corporation. So the system is simplified and the resist ability to disturbing is improved strongly.The using of digital phase detector makes the time measure's precision improved greatly. ARM chip let the system have better real time performance. And the embedded system provides good operation and reliability.