Abstract: A three-wire sensor interface for field wiring of conventional on/off type control sensors that delivers power to the sensor, provides a normally open control output from the sensor and, concurrently, provides a normally closed control output from the sensor. The sensor interface includes a plurality of external terminals including a normally open external terminal for electrically connecting to zero, one, or more normally open load devices to control the operation of the normally open load device, and a normally closed external terminal for electrically connecting to zero, one, or more normally closed load devices to control the operation of the normally closed load device. A plurality of interface terminals are preferably electrically coupled between the sensor interface and the sensor and include a normally open control terminal and a normally closed control terminal.

Abstract: A sensor package for proximity detectors adapted for use with materials having a significant angle of repose. The sensor package includes a hollow housing defining a cylindrical main body adapted to house proximity detection circuitry and a non-planar tip disposed on one end of the housing adjacent the main body. The tip portion is preferably tapered in its diameter from a dimension generally equal to the diameter of the main body to a dimension less than the diameter of the main body. The tip is adapted to house a sensing element electrically coupled to the proximity detection circuitry and disposed on an inner bottom surface of the tip portion. Preferably, the taper of the tip is selected to substantially match the angle of repose of the materials to be sensed, and may take on a wide variety of shapes including cone, frustum, pyramid, round and hemispherical.