Abstract: Both power to and detection signals from a remotely located condition monitoring device are provided via a single wire with return through the vehicle frame. A load switching circuit connected and responsive to the output of the condition monitoring device causes a particular current to be drawn from the line when the device and signal status are normal than when either is not. An indicator circuit connected into the line and responsive to the current drawn by the device and loading circuit provides a failsafe indication to the operator of the monitored condition and/or operational status of the system circuitry.

Abstract: At periodic intervals a timer initiates a short duration pulse from a one-shot that changes the state of a flip-flop functioning to deactivate a status indicator. The one-shot pulse also activates a driver circuit that energizes an inductive test coil positioned within the province of an electromagnetic field generated by a field variation detector. The variance in the field created by the test coil is sensed by the detector receiver which shapes and modifies the response in accordance with the characteristics of the detection circuitry and the duration of the one-shot pulse. The characteristic of the modified pulse waveform is gated back to the flip-flop that switches states to reactivate the status indicator to its original indication. A change in the detector sensitivity and/or performance will effect a modified pulse waveform exhibiting a characteristic different from that required to reset the circuitry and thus an abnormal operation is indicated.

Abstract: A tire condition sensing circuit includes a ferrite element that changes from a ferromagnetic to a nonferromagnetic state in response to a temperature increase above the material Curie point. The change in state of the element affects the sensor circuit operation such that a normal inductive coupling effect is altered and an abnormal tire condition indicated.

Abstract: Apparatus and method for extending the operating range of a condition monitoring system that detects the occurrence of an abnormal condition on a first member moving relative to a second member; the system including a sensor circuit on the first member adapted to be responsive to the condition being monitored and a monitoring circuit on the second member adapted to being affected by the proximate presence of a close-circuited sensor circuit to provide detection signals to circuit means for indicating the condition of the moving member indicative of the open or close-circuited sensor circuit. The system is characterized by a monitoring circuit operating at the threshold of an oscillatory and nonoscillatory state and a close-circuited sensor circuit configuration that affects the monitoring circuit irrespective of its operational state.

Abstract: In an electronic detection system, signals indicative of a detected mass of material are related to a selected mass velocity and a detection aperture through which the mass is moved. The pulse output signal from the detector, exhibiting a period related to the mass velocity and aperture length, is conditioned and enhanced as a valid detection signal while all others due to noise, etc. are rejected being outside of a selected threshold for the particular mass velocity and aperture length.