Ultrasonic Sensing Basics for Liquid Level （超声波液位传感基础）.pdf

Application Report SNAA220A– March 2015– Revised June 2015 Ultrasonic Sensing Basics for Liquid Level Sensing, Flow Sensing, and Fluid Identification Applications Amy Le ABSTRACT The need for accurate and reliable sensors is growing in so many markets around the world, such as industrial and manufacturing, automotive, medical, energy, and smart grid applications. The designers and end-users of these sensors are counting on newer technologies that use less power and deliver higher accuracy -- technologies that will eliminate moving parts and allow sensing in remote locations and in less- than-ideal conditions. One of the most effective areas of sensor technology is ultrasonic, the science that measures the time interval between an ultrasonic signal that is sent and received, or what is commonly referred to as time- of-flight (TOF). TI is leveraging its ultrasonic expertise to deliver new signal conditioning solutions to fluid level sensing, fluid identification, flow metering, and distance sensing customers with its latest products (TDC1000 and TDC7200) based on time-to-digital converters (TDCs). This application note provides an introduction to how Texas Instruments Ultrasonic Sensing solutions (TDC1000 and TDC7200) can be applied to popular applications such as liquid level sensing, flow sensing, and fluid identification. Topic Page 1 General Theory of How Ultrasonic Sensing Works 2 2 TDC1