Design Of Metal Tube Rotameter On Ethernet

Metal tube rotameter is a flux measuring device based on the principle of floater ascending or descending in the vertical cone-shaped tube with the flux changing. The subject does research on the problems of the current flowmeter's measurement accuracy, intelligence and communication. The paper introduces a design of network metal tube rotameter.Network intelligent metal tube rotameter consists of flowmeter sensor system and network communication system. The flowmeter sensor system constructs a low-power hardware system based on MSP430F149 MCU. It adopts a new magnetoresistive sensor HMC1501 to implement measuring flux signal with high accuracy. The system has the function of local displaying, cumulating and parameter setting.Also,it supply two-wire current signal output, RS232 & RS485 communication interfaces that achieves intelligent instrument integration. In the network communication system uIP protocol is transplanted and Web Server's function is realized. The system is designed based on LPC2114 MCU with the core of ARM7. It is a universal conversion module between Uart and Ethernet, accordingly connecting the metal tube rotameter to Ethernet.The system implements metal tube rotameter's calibration and temperature compensation by software, so high-accuracy measuring of the flux signal is realized in various environments. Ultralow-power consumption SCM MSP430F149 and XTR115 are adopted to realize two-wire 4～20mA current loop output and signal transmission by RS232/485. The presicion is higher than 1.0-level, testing by the standard flowmeter with 0.2-level,and the system has little temperature drift. Meanwhile,LPC2114 and Ethernet controller CS8900 are adopted to finish Ethernet communication. Overall this paper has certain reference value on Ethernet connection research and remote monitoring of the embedded equipments.