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US 4,906,992 AGranted
Single track absolute encoder
AssigneeDynamics Research Corporation
InventorsSidney A. Wingate, Gregory J. Rust
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Abstract
An absolute encoder providing a multi-bit output binary code indicative of the position of a rotary or linear scale. The encoder employs a code track, which contains a serial code, and a clock track. The encoder may be either rotary or linear, and may be implemented optically, magnetically, inductively, capacitatively or by any other binary sensing technique.
Claims12
An absolute encoder providing a unique N-bit output word indicative of absolute position, comprising:
- a disc mounted for rotation about an axis, said disc having;
- a single circumferential serial code track having a plurality of circumferentially arranged binary segments, whereby each combination of N-2 adjacent segments of said code track provides N-2 bits of said output word;
- one circumferential clock code track having a plurality of circumferentially arranged alternating binary segments, whereby each combination of 2 adjacent segments of said clock track provides 2 bits of said output word;
- means for reading said clock code track to produce a clock signal indicative of the transition of said clock code and further producing 2 bits of said output word;
- means for reading said serial code track in response to said clock signal to produce N-2 bits of said output word;
- and
- means responsive to said means for reading said clock code track and said means for reading said serial code track to provide a unique N-bit output word representative of absolute rotary position of said disc.
4 more elements
An absolute encoder comprising:
- a disc mounted for rotation about an axis, said disc including a single circumferential serial code track having binary segments, wherein a predetermined number of adjacent segments defines a unique serial code for each segment of disc rotation, and a single circumferential clock track having alternating binary segments;
- first sensing means for sensing the clock track and producing a clock signal representative of relative disc rotation and direction;
- first reticle means for defining at least two positions at which said first sensing means senses the clock track;
- second sensing means for sensing the serial code track in response to said clock signal and producing a serial code;
- second reticle means for defining at least two positions at which said second sensing means senses the serial code track;
- means for converting said serial code to a parallel word;
- means for storing said parallel word;
- and
- means for converting said parallel word to a signal representative of the relative angular position of said disc.
6 more elements
An absolute encoder providing a unique N-bit output word indicative of absolute position, comprising:
- a scale mounted for relative motion with respect to a reference, said scale having:
- a single serial code track having a plurality of binary segments, wherein a predetermined number of adjacent segments defines a unique serial code for each segment of relative motion;
- and
- a single clock track having alternating binary segments;
- first means for sensing the clock track and producing a clock signal representative of relative movement and direction;
- second means for sensing the serial code track in response to said clock signal and producing a serial shift register code signal;
- a shift register having selectable left-to-right and right-to-left storage capabilities;
- means, responsive to the clock signal, for selectably storing said serial code in the shift register in said left-to-right or right-to-left mode depending upon relative direction of movement of said scale;
- and
- means for converting said serial shift register code to a signal representative of the relative position of said scale.
7 more elements
Dependencies are inferred from the claim text.