Apparatus including a selectively connectable isolation transformer for determining the speed and direction of a rotating object

摘要

In one aspect of the present invention, an apparatus determines the rotational speed and direction of a rotating object. The apparatus includes a sensor adapted to detect the speed and direction of the rotating object and responsively produce a frequency signal indicative of the speed of the rotating object and a direction signal having a voltage value indicative of the rotational direction of the rotating object. A distinguishing stage receives the frequency and direction signals, and determines the voltage value of the portion of the direction signal that coincides with the falling edge of the frequency signal. Responsively the distinguishing stage produces a control signal having a voltage level responsive to the determined voltage value of the direction signal. A converting stage receives the frequency signal and responsively produces an output signal having a DC voltage proportional to the frequency of the frequency signal. A directional stage receives the control signal and the output signal, and changes the polarity of the output signal in response to the voltage level of said control signal. An output device receives the polarized output signal, and stores the magnitude and polarity of the output signal.