US 4,327,362 AGranted

Meter rotor rotation optical sensor

AssigneeRockwell International Corporation

InventorRobert J. Hoss

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Abstract

Electrical consumption registered in a watthour meter is converted into an electrical analog suitable for transmission to a remote monitoring site by reflecting light off the watthour meter rotor, the light being periodically interrupted during each rotor rotation by a darkened light absorbing area of the rotor which traverses the light beam, passing the light to and from the meter through fiber optic cables and digitally counting at a distant location each of the pulses corresponding to the rotor rotation which are transduced from the light reflections. By generating the light from an AC signal, AC signal processing techniques employed in the light reflection detection circuitry ensure a useable electrical analog with minimal likelihood of error otherwise arising from spurious noise and varying ambient temperature related signals.

Claims10

Dependent claims

Rotation sensing apparatus for monitoring at a remote location the rotations of a meter rotor having a light reflecting surface except for a circumferentially disposed non-reflecting portion whose arc is less than the meter circumference, comprising:

a light source at the remote location from the meter whose rotor rotations are to be monitored including a transducer for converting electric energy to light and an AC signal source for energizing said transducer;
a first fiber optic bundle for routing the light from said source to the meter to be beamed onto the circumferential section of the surface of the rotor containing the non-reflecting and reflecting portions at it rotates therepast;
a second fiber optic bundle for routing light reflected from the surface of said rotor back to the remote location;
detection means at the remote location, including a transducer for converting the periodic light reflections from the surface of the rotor as it rotates to electrical AC analogs, discrimination means for passing only AC analogs which bear a predetermined relationship to said AC signal source and means for converting the passed AC analogs to electrical pulse analogs, and
counting means connected to said detection means for accumulating the number of said electrical pulse analogs.

2 more elements

Dependencies are inferred from the claim text.