ABB ProcessMaster FEP630 Series Operating Instruction

Also see for HygienicMaster FEH630 series: Manual Operating instruction Manual

Contents

ABB ProcessMaster FEP630 Series Operating Instruction Manual pdf 11 page image

FEP630, FEH630 ELECTROMAGNETIC FLOWMETER | OI/FEP630/FEH630-EN REV. D 11Measuring principleMeasurements performed by the electromagnetic flowmeter arebased on Faraday’s law of induction. A voltage is generated in aconductor when it moves through a magnetic field.1 Magnet coil2 Measuring tube in electrode plane3 Measuring electrodeFigure 4: Electromagnetic flowmeter diagramvDBU ~1vDqv  42qvU ~1U 1 Measuring spanB Magnetic inductionD Electrode spacingv Average flow velocityqv Volume flow rateWith the device-relevant application of this measuring principle,a conductive measuring medium flows through a tube in which amagnetic field is generated perpendicular to the flow direction(see Figure 4).The voltage induced in the measuring medium is tapped by twodiametrically opposed electrodes. This measurement voltage isproportional to the magnetic induction, the electrode spacingand the average medium velocity v.Taking into account that the magnetic induction and theelectrode spacing are constant values results in a proportionbetween the measurement voltage U 1 and the average mediumvelocity.From the calculation of the volume flow rate follows that themeasurement voltage is linear and proportional to the volumeflow rateThe induced voltage is converted by the transmitter tostandardized, analog and digital signals.