Design Of Time Difference Ultrasonic Flowmeter Based On ARM

Ultrasonic Flowmeter is widely applied in the fields of meteorology, petroleum, chemical, medicine, water resource management, for the advantages non-contact, high accuracy, ease-to-use and so on. Great progress has been made on Ultrasonic Flowmeter, in recent years, with the development of digital signal processing technology and microprocessor. A new kind Flow meter based on ARM is introduced in the thesis, which accords with the embedded system development.The theory of time-difference Ultrasonic Flowmeter is introduced, also the hardware based on ARM LPC2214, the software and the method of fighting time realizing are designed. By analyzing and absorbing foreign advanced Ultrasonic Flowmeter technology and theory, the new way to calculate fighting time is presented. In system hardware, the ultrasonic transmitting, receiving and amplifying circuits are designed, and the ultrasonic signal is digitalized by high speed A/D converter. The LPC2214 ARM system circuit included system power, memory, human interface and communication faces are introduced. The system software is designed base on the ARM-uClinux embedded platform, also the steps how to make the embedded operation system uCLinux emergent to the ARM hardware are presented. In order to heighten the time precision, in system signal process part, the digital filter has designed to high the signal to noise. By checking the variance ratio and interpolation the difference time accuracy of calculating is heightened.This design makes good use of the LPC2214 on chip materials. The human interface and debug port makes system software design and debug more easily. This also simplifies the system hardware design, reduces design costs, and makes the design more reasonable.