Abstract: A two-wire transducer-transmitter for non-contact temperature measurement provides, in a unitary housing, a radiation sensing device producing a signal in response to sensed infrared or visible radiation, and electronic circuitry for processing the signal to provide at a two-wire output a current linerarly proportional to the sensed target temperature, on the same two wires as input power preferably in the range of from 4 to 20 milliamperes D.C. full scale.
Abstract: A radiation detector senses ambient radiation within the cavity of an instrument, and then radiation from a target object, the sensed radiation from within the cavity following substantially the same optical path within the instrument as the radiation from the target object, thus minimizing error due to internal cavity temperature and other disturbances during measurement of radiation from the target object.