Inventors:
Bruce W. DuVall - Colorado Springs CO
James W. Valentine - Colorado Springs CO
Kenneth O. Morey - Colorado Springs CO
Assignee:
The United States of America as represented by the United States
Department of Energy - Washington DC
International Classification:
G01F 2326
Abstract:
An inductive level sensor has inductively coupled primary and secondary windings. Circuitry drives the primary with an AC signal of constant current magnitude and selected frequency f to induce in the secondary, a voltage signal V of magnitude. vertline. V. vertline. , frequency f and phase difference. phi. from the driving signal. Circuitry operates to generate a voltage output signal proportional to. vertline. V. vertline. cos (. phi. -. theta. ), where. theta. is a selectively set phase shift factor. By properly and selectively adjusting the frequency f and phase shift factor. theta. , an output signal. vertline. V. vertline. cos (. phi. -. theta. ) can be provided which self-compensates for changes in mutual inductance caused by operating temperature variations so that an output signal is produced which is substantially linearly proportional to changes in the level of a pool of liquid metal being monitored. Disclosed also is calibration circuitry and circuitry for converting the voltage signal. vertline. V. vertline. cos (. phi. -. theta. ) into a current signal.