Abstract: A magnetic flow meter includes a cylindrical vessel within which electrodes are placed directly opposite each other about a magnetically permeable core. In that way, two flow channels are obtained in the vessel. A common magnetic field is applied across both flow channels. The magnetic flow meter is used in conjunction with a controller which monitors amplitude modulated signals representative of applied magnetic field and induced electric field. These amplitude modulated signals are passed to Sigma-Delta modulators, which directly digitise the amplitude modulated AC signals into digital pulses. The controller is capable of monitoring reverse flow through the meter, and to store results until forward flow resumes. Moreover, the controller generates a driving signal for coils which generates a magnetic field, the coil being placed in conjunction with a capacitor which causes resonance. This reduces power consumption by the coil in driving the meter.