Abstract: An electromagnetic flowmeter capable of accurately measuring the flow rate of fluid conveyed on a line in either direction. The flowmeter includes a primary whose flow tube is provided with electrodes yielding a signal depending on the flow rate of the fluid intersecting a magnetic field established in the tube, the sense of the signal changing with the direction of flow. This electrode signal is applied to a secondary in which the electrode signal is converted by demodulator means into a d-c signal whose magnitude is a function of flow rate and whose polarity depends on the sense of the electrode signal. This d-c signal is converted into variable-frequency pulses which exhibit a duty cycle proportional thereto, the pulses being sampled and fed back through a feedback loop to one input of a summing junction to which the electrode signal is also applied as another input, the ouptut of the junction being fed to the demodulator means.

Abstract: An electronic totalizer interposable in the line of a two-wire transmitter having a transducer which converts a metered variable into a current signal that is conveyed over the line to a receiving station, the same line delivering direct current power from the station to the transducer and to the totalizer. The totalizer input circuit includes a resistor through which the current signal flows to produce a corresponding voltage signal, the voltage signal being applied to a resettable integrator to produce a time-integrated voltage which rises above a base level at a rate depending on the varying magnitude of the voltage. The rising integrated voltage is applied to a comparator having a threshold set by a reference voltage to produce an output signal when the integrated voltage reaches the threshold. The output signal is fed back to the integrator to effect resetting thereof to the base level, the output signal also serving to trigger a one shot generating a pulse which is applied to a digital counter.