초록 ▼

A magnetic flowmeter includes a coil driving circuit which controls both the maximum, steady state current and the current rise time through the coils and makes them independent of the inductance of the particular coil being driven. The maximum current is set by a reference voltage derived from a co

A magnetic flowmeter includes a coil driving circuit which controls both the maximum, steady state current and the current rise time through the coils and makes them independent of the inductance of the particular coil being driven. The maximum current is set by a reference voltage derived from a common source with a second reference voltage utilized in the signal processing chain. The ratio of these reference voltages therefore remains constant and the output signal is independent of the absolute value of the common source of the two reference voltages.

대표청구항 ▼

In a magnetic flowmeter comprising a body adapted to be connected in a flow system for measuring the flow of a fluid therethrough, coil means for generating a magnetic field in said fluid flowing through said body, means for producing an output voltage dependent on the electric field generated in sa

In a magnetic flowmeter comprising a body adapted to be connected in a flow system for measuring the flow of a fluid therethrough, coil means for generating a magnetic field in said fluid flowing through said body, means for producing an output voltage dependent on the electric field generated in said fluid flowing through said magnetic field, and signal processing means for converting said output voltage to an output signal, the improvement comprising a reference voltage source, pulse forming means operatively connected to said coil means for producing pulses of filtered direct current through said coil means, said pulse forming means including means operatively connected to said reference voltage source and responsive to said reference voltage source for controlling the current of said pulses and hence for controlling the magnetic field produced by said coil means, and means operatively connected to said reference voltage source for generating a second reference voltage dependent on said first reference voltage, said second reference voltage being operatively connected to said signal processing means, said signal processing means including ratioing means responsive to said output voltage and to said second reference voltage for making said output signal dependent on said second reference voltage, whereby changes in said output voltage caused by changes in said reference voltage are compensated in said output circuit by changes in said second reference voltage, and said output signal is made substantially independent of fluctuations in said reference voltage.