2005 Innovation Award Winner

2005 Flow Control Magazine Innovation Award

Product	:	ADMAG AXF Magnetic Flowmeter
Release	:	August 2004

The 2005 Innovation Awards program received over 3,500 votes for more than 45 nominees, which included some truly innovative fluid handling technologies. Yokogawa's ADMAG AXF Magnetic Flowmeter was one of the 12 outstanding products to be selected for an award this year.

The ADMAG AXF magnetic flowmeter features electrode coating diagnostics to ensure the accuracy of the meter isn't impeded by build-up of material on the electrode, a situation that requires periodic maintenance. With conventional magmeters, the maintenance schedule is arrived at based on simple experience and observation. With the new coating diagnostic function of the ADMAG AXF it is possible to monitor the status of the electrodes in real time. The coating level can be judged by measuring the resistance between the electrodes and the earth rings. A small, rectangular current pulse is fed from the electrode to the earth ring in order to measure the resistance using Ohm's law. The pulse frequency is synchronized with even multiples of the flow signals' frequencies. When the flow signals are operated, the pulse frequency is cancelled out and thus does not influence the operated computation outputs. Conversely, when the coating diagnosis signals are operated, the flow signals are cancelled out with no influence on the diagnosis results. This kind of signal processing makes electrode coating diagnosis possible even during flow measurement. The severity of the coating is judged in four levels based on pre-defined values. Level 3 corresponds to a warning and a status output signal can be generated. When the coating level is judged to be level 4, an alarm output can also be set. Although the coating criterion levels are preset to reference values at the factory, they can be changed by users depending on their application.