Design and functionD184B140U02 FSM4000 17Pos: 8 /Überschriften/1/A - C/Aufbau und Funktion @ 0\mod_1129797620733_3101.doc @ 31402 Design and functionPos: 9 /Aufbau und Funktion/Durchfluss/FXE4000/Messprinzip @ 0\mod_1128409359748_3101.doc @ 32882.1 Measuring principleMeasurements performed by the electromagnetic flowmeter are based on Faraday’s law ofinduction. A voltage is generated in a conductor when it moves through a magnetic field.This principle is applied to a conductive fluid in the measuring tube through which a magneticfield is generated perpendicular to the flow direction (see schematic).The voltage induced in the fluid is measured by two electrodes located diametrically oppositeeach other. This signal voltage U E is proportional to the magnetic induction B, the electrodespacing D and the average flow velocity v.Considering that the magnetic induction B and the electrode spacing D are constant values, aproportionality exists between the signal voltage U E and the average flow velocity v. From theequation for calculating the volume flowrate, it follows that the signal voltage is linearlyproportional to the volume flowrate: U E ~ q v.The induced voltage is converted by the transmitter to standardized, analog and digital signals.G00005123Fig. 6: Electromagnetic flowmeter schematic1 Magnet coil2 Measuring tube in electrode plane3 Signal electrodeU E Signal voltageB Magnetic inductionD Electrode spacingv Average flow velocityq v Volume flowU E ~ vDB ⋅⋅qv = vD ⋅42πU E ~ q vPos: 10 /======= Seitenumbruch ======== @ 0\mod_1126532365768_3101.doc @ 3830
