Infrared transducer-transmitter for non-contact temperature measurement

Claim 1

Transmitter-transducer apparatus for non-contact temperature measurement wherein there is provided, on the same two wires, both a power supply current for the apparatus and an output signal current representative of a sensed target temperature, said apparatus comprising a housing, an opening in said housing for admitting to said housing radiation from a target object, optical means disposed in said opening in axial alignment with said opening, radiation detector means disposed in said housing in optical alignment with said optical means and adapted to receive radiation transmitted by said optical means, and signal processing means disposed in said housing and adapted to receive from said radiation detector means an electrical detector signal responsive to radiation incident on said radiation detector means, said signal processing means including means to amplify and linearize the signal to produce an output which is linearly proportional to the temperature of a target object, and a two-wire lead electrically connected to said signal processing means and adapted to be electrically connected to a remote power supply and a load, power supply regulator means operatively connected to said lead to supply to said apparatus a constant input current, and elecrical circuit means for summing said input current and the output current of said signal processing means to produce the output current of the apparatus, said lead being electrically connected to said circuit means whereby both the power supply current for the apparatus and the output signal current are carried by said lead.