基于HART总线的双量程差压流量计  

Dual Range Differential Pressure Flowmeter Based on HART Bus

作　　者：张宝良[1] 纪波峰 纪纲 

机构地区：[1]中石化股份天津分公司,天津300271 [2]上海同欣自动化仪表有限公司,上海200070

出　　处：《自动化仪表》2016年第8期93-95,共3页Process Automation Instrumentation

摘　　要：差压式流量计由于其自身的固有特点,量程比不够宽广.采用增设-台低量程差压变送器的方法,能有效地扩大量程比,但仍沿用4 -20 m A 模拟量传送信号.由于信号要经过D /A 和A /D 两次转换,将会损失0. 1% FS 的准确度,因此采用数字信号传送的方式挽回这-损失,使流量信号处理成为无差运算.该方法不仅提高了系统准确度、减小了零漂、降低了仪表功耗,而且节省了工程投资.这-方法也同样适用于单量程差压流量计.Differential pressure （DP） flowmeter features a low turndown ratio because of its inherent characteristics. To effectively increase itsturndown ratio,a lower range DP transmitter is added,and 4 -20mA is still used as transmitting signal. Because two times of conversions, D/Aand A/D are needed,the accuracy may lose by 0. 1% FS. By using digital signal,this loss can be avoided,and the flow signal processing will beno error operation. This method not only improves system accuracy, reduces zero drift, decreases power consumption, but also saves investment ofproject. This method is also available in single range DP flowmeters.

关 键 词：差压式流量计 智能变送器 双量程 模数转换 不确定度 量程比 HART总线 节能降耗 

分 类 号：TH814[机械工程—仪器科学与技术] TP336[机械工程—精密仪器及机械]