Magnetostrictive linear position detector with temperature sensors

摘要

The present invention is a combined magnetostrictive linear displacement detector and plural location temperature detector. The combined apparatus produces a composite signal for transmission on a 2 wire transmission line. The resistances of the temperature sensitive resistors as well as two reference resistors are measured in a predetermined sequence. The linear displacement is measured by the length of time required for a torsional strain to travel along the magnetostrictive wire to the position of the magnet. A pulse generator generates a predetermined number of pulses for each resistance measurement having pulse period corresponding to the measured resistance, with the minimum such pulse period preferably being greater than twice the maximum time required for a torsional strain to propagate the length of the magnetostrictive wire. An electrical signal is supplied to the transmission line when either said pulse generator generates a pulse or the induced electrical signal is detected. The time between the pairs of pulses indicates the linear displacement fixed by the magnet. The time between pulse pairs is a measure of one of the resistances. The combined apparatus of the present invention also periodically degausses the magneteostrictive wire at a time when no displacement measurement is taking place.