ARM Technology Developed For Transit-time Ultrasonic Flowmeter
Keywords:Ultrasonic flow meter, Transit-time principle, LPC2214,uClinux,digital filter
The 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.
The theory of time-difference ultrasonic flow meter is introduced,also the hardware based on ARM LPC2214, the software and the method of flighting time realizing are designed accordingly.By analyzing and absorbing foreign advanced ultrasonic flow meter technology and theory, the latest way to calculate flighting 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 based on the ARM-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.
Ultrasonic flow meter is widely used in the industries of water resource management,meteorology,petroleum,chemical,medicine,etc.Ultrasonic flow meters has many good features,e.g.clamp-on installing way, no cutting pipe, no pressure drop,wide pipe size range, wide flow rate and velocity,easy to operate,etc.Great progress has been achieved on ultrasonic flow meters,and in recent years,with the development of digital signal processing technology and microprocessor, a kind of ultrasonic flow meter has been developed on the basis of ARM and is accorded with the embedded system development.