hi
As you know , The principle of operation for the magnetic flow meter is based on the Faraday’s Law of Electromagnetic Induction.An electrical current (I) is applied to a coil package inside the flowmeter.
As a result, a magnetic field (B) is created across the metering pipe.When a conductive liquid flows through the magnetic field, a small voltage (u) is induced.

now, in your opinion , how work below flow meter ? Why use of six wire?

 

Possibly two wires to excite the field windings, two wires to monitor the field current (remote sense) and two wires for the generated voltage. Reason for remote sense on excitation is that if the length of transmission lines causes a reduction of excitation, without remote sense, calibration could (would) be off.