Abstract: The invention provides an apparatus and method to confirm or deny the presence of an object within the scan area of an ultrasonic sensing system by requiring that any object be identified on at least two consecutive scans of the sensing system and using scan energy patterns which occur at irregular repetition times to selectively reject spurious direct or reflected signals present in the area. A generator of predetermined pattern burst of ultrasonic energy is arranged to produce one such burst of ultrasonic energy and a timing signal is coupled thereto so as to apply timing signals to cause production of the bursts. The timing signal source produces timing signals only according to a varying pattern whereby separation between adjacent signals meet certain present parameters. The energy patterns are applied to a transmitter which applies them to a scan area whereby the echo or returned energy from an object in the scan area is received and stored.

Abstract: A magnetic sensor for detecting the leading edge of a ferrous target as it passes the centerline of the sensor. The magnetic sensor includes a coil output representing the rate of change of magnetic flux as the target passes the sensor. The coil output is differentiated to provide a signal having a zero crossover point corresponding to the time at which the leading edge of the target passes the centerline of the sensor. The differentiated signal is applied to a zero crossover threshold detector to provide a first pulse, the trailing edge of which corresponds to the time at which the target's leading edge is coincident with the sensor centerline. Additional means provide a second pulse whose leading edge corresponds to the time at which the leading edge of the target is coincident with the centerline of the sensor.

Abstract: An event rate counter for measuring the number of events occurring per unit of time with an input pulse train having a fixed number of pulses per each occurrence of the event, wherein the input pulse train is scaled by a multiplier and divider to provide a direct readout in events-per-unit of time. The input pulse train is amplified and applied to a level detector, the output of which is a logic level pulse train having frequency equal to the frequency of the input signal. The pulse train frequency is monitored by a frequency detector for controlling a commutative switch. For low frequency pulse trains, the switch gates the pulse train from the level detector first to the multiplier, the output of which is gated by the switch to the divider. The multiply-divide sequence order is reversed by the switch for high frequency pulse trains thereby extending the dynamic frequency range of the counter.

Abstract: A transformerless triac control circuit provides direct on/off control of loads including loads requiring a high current. An on/off decision is made twice each period of the source voltage, and the on/off decision results from the happening or the nonhappening of an event such as the detection of a conductive body.

Abstract: An electronic limit switch assembly including a sensor and a switching circuit controlled thereby contained in separate molded plastic housings. The sensor housing and the switching circuit housing are secured together with respective mating walls thereof in abutment and electrically coupled by leads protruding through the mating walls and protectively contained in a cavity in the mating wall of the sensor housing. A sensing coil is mountable for side sensing between a side wall of the sensor housing and an interior wall spaced therefrom defining a part of the cavity for side sensing and is also mountable for end sensing against an end wall opposite the mating wall and underlying the interior wall. Elements of the switching circuit are mounted on a printed circuit board and elongate conductive members secured to the board and connected with elements of the circuit protrude through mating holes in the top of the switching housing which function as terminal posts, heat sinks and circuit board mounts.

Abstract: A linear oscillator circuit has a resonant circuit which develops an oscillating voltage V.sub.R having an amplitude proportional to a distance between a conducting body and the resonant circuit located within a probe. A control power drive circuit coupled to the output of the resonant circuit switches a current through the resonant circuit during each period of oscillation of the voltage V.sub.R. A reference current source is coupled to the control power drive circuit for drawing a current through the control power drive circuit and the resonant circuit. The magnitude of the current is equal to the magnitude of an independently established reference current. A detector circuit responsive to the value of the amplitude of oscillation may be provided to indicate the distance of the conductive body from the resonant circuit-containing probe.

Abstract: A detector for a dynamic phenomenon with a cyclically varying condition, as motion of a rotating part. At least three digital sensors are separated in phase with respect to the cyclic condition. The instantaneous outputs of the sensors have a plurality of repeating sequential states so long as the dynamic phenomenon exists. The instantaneous outputs of the sensors have at least one state which does not occur during existence of the dynamic phenomenon but which does occur in the absence thereof. Logic circuits respond to the digital sensor outputs and detect information about the dynamic phenomenon. Detection of the repetition rate of an instantaneous output state of the sensors provides a measure of speed. An absence of rotation is indicated by the occurrence of another output state. In another disclosed embodiment, the detector monitors a three phase power system and detects a phase outage by the occurrence of an abnormal sensor output state.

Abstract: A proximity sensor oscillator, having a resonant circuit in which the power loss is inversely related to the distance of a conductive body from a probe containing a part of the resonant circuit, produces an oscillating output signal in the resonant circuit with a peak amplitude that varies with power loss and distance. A power source provides either the current or the voltage component of electrical power at a substantially constant value independent of changes of resonant circuit power loss and is periodically switched to the resonant circuit to provide an average input power thereto. The power loss of the resonant circuit loads the source, and thus the other component of power oscillates within the resonant circuit at a peak amplitude linearly related to the inverse of the power loss.