发表于：2009/5/25 21:11:49
#0楼
工业现场仪表通常是两线制的。这两根线即作为电源又输送信号，标准的信号范围在电流4mA--20mA之间。实际上，这里有一个限定，这就是，你现场的仪表必须是低功耗的。也就是说，你现场的仪表必须在4mA的电流消耗内完成传感器的前期处理，对于象压力和温度这样的现场仪表这是很容易完成的，但对于象电磁流量计这样的仪表来说就不那么轻松，大家知道，电磁流量计工作基于法拉第电磁感应定律，这就要求它的工作要在激励磁场中完成，按照法拉第电磁感应定律U=BLv，B磁场的强度越强，流量计产生的信号U越大，因而要想在复杂的工业环境里让流量计正常工作激励磁场必须有一定的强度。磁场的激励电流也必须达到一定强度。这就是两线制电磁流量计的技术难点。传统的电磁流量计是四线制的。但对于工业现场来讲两线之仪表四线制不可比拟的优越性，因而两线制电磁流量计一直是现场工程师和仪表生产厂家的追求。世界上知名仪表制造商做过不停的努力，但技术上很难突破。我的朋友现在研究项目试图不以牺牲性能为代价，现在这个项目已有所突破。我朋友给我解释，流量计需要一定的磁场的强度，但这里的磁场的强度不需作功，因而这个项目在理论上是成立的。
I, an engineer of automation ,have a friend studing in Europe whose project on 2 wires Mag-flowmeter useing a new technology "sensebridge"which is a kind of versatile block,claimed can be used to make any kind of sensors.he said to me he would come back to china to open a company .the company would do research on sensors,the first product will be 2 wires Mag-flowmeter.and the second will be followed every kind of sensors based on "sensebridge block". firstly ,I need friends who have knowledge about sensors helping me.people who are interested, plz, add me.
I, an engineer of automation ,have a friend studing in Europe whose project on 2 wires Mag-flowmeter useing a new technology "sensebridge"which is a kind of versatile block,claimed can be used to make any kind of sensors.he said to me he would come back to china to open a company .the company would do research on sensors,the first product will be 2 wires Mag-flowmeter.and the second will be followed every kind of sensors based on "sensebridge block". firstly ,I need friends who have knowledge about sensors helping me.people who are interested, plz, add me.
