Inductive flow meter evaluation circuit - has two scanner stores detecting peak and trough voltages generated by flow through alternating magnetic field

摘要

The inductive flow meter has one electromagnet producing an alternating magnetic field in the flow region. The meter in conjunction with an electrode pair connected to an evaluation circuit is designed to use a simple circuit and operate free of stray signal influences, thus achieving relatively high accuracy. In partic., either direct voltage drift in the amplifier or the polarisation voltage is compensated. A first voltage scanner store (20) in the evaluation circuit (14) is controlled so as to detect and store the peak value in each electrode voltage period. A second store (21) retains the trough value. Both store outputs are input to a differential amplifier (26), whose output is fed to a meter via an averaging circuit (27).