Back to results
US 5,021,781 AGranted
Two stage quadrature incremental encoder
AssigneePitney Bowes Inc.
InventorsEdilberto I. Salazar, Gilbert N. Riley
Life of this patent
Estimating the term…
Abstract
An incremental position encoder and method are disclosed herein for a close loop position control system, for example, for positioning a printing device in an electronic postage meter. The incremental position encoder and method includes three channels, first and second of which provide signals for coarse position determination and first or second and third of which provide signals for fine position determination.
Claims24
An incremental position encoder comprising:
- a movable element whose movement is to be encoded;
- first pulse generating means for providing first and second pulse signals having a number of pulses related to an incremental movement of said movable element, the numbers of pulses in said first and second signals being equal for a given incremental movement of said movable element, the widths of the pulses of said first signal being equal to the widths of corresponding pulses of said signals being substantially out of phase, but not less than by 180.degree.;
- and
- second pulse generating means for providing third signal having number of pulses related to incremental movement of said element, the number of pulses in said third signal being equal to the number of pulses in said first and in said second signals for the same given incremental movement of said element, the widths of the pulses of said third signal being less than the widths of the pulses of said first and second signals, and the pulses of said third signal starting before the start of corresponding pulses of one of said first and said second signals and ending before the end of the pulses of said one signal.
1 more element
A method of generating signals related to incremental movement of a movable element comprising:
- generating first and second pulse signals having a number of pulses related to a incremental movement of said movable element, the numbers of pulses in said first and second signals being equal for a given incremental movement of said movable element, the widths of the pulses of said first signal being equal to the widths of corresponding pulses of said second signal and corresponding pulses of said first and second signals being substantially out of phase, but not less than by 180.degree.;
- generating a third signal having a number of pulses related to incremental movement of said element, the number of pulses in said third signal being equal to the number of pulses in said first and in said second signals for the same given incremental movement of said element, the widths of the pulses of said third signal being less than the widths of the pulses of said first and second signals, and the pulses of said third signal starting before the start of corresponding pulses of one of said first and said second signals and ending before the end of the pulses of said one signal.
Apparatus for determining a given incremental movement of a movable element from a first fine home position to a second fine home position, comprising:
- first pulse generating means for generating first and second pulse signals having a number of pulses related to the incremental movement of said movable element between said first fine home position and a second coarse home position, the numbers of pulses in said first and second signals being equal for said incremental movement of said movable element, the widths of the pulses of said first signal being equal to the widths of corresponding pulses of said second signal and corresponding pulses of said first and second signals being substantially out of phase, but not less than by 180.degree.;
- second pulse generating means for generating a third signal having a number of pulses related to said incremental movement of said element, the number of pulses in said third signal being equal to the number of pulses in said first and in said second signals for said incremental movement of said element, the widths of the pulses of said first and second signals, and the pulses of said third signal starting before the start of corresponding pulses of one of said first and said second signals and ending before the end of the pulses of said one signal;
- means for counting the transitions of the pulses of said first and second signals starting with movement of said movable element from said first fine home position, the number of said transitions being related to said incremental movement of said movable member;
- and
- means for detecting:
- when the number of transitions corresponds to the distance between said first fine home position and second coarse home position;
- the simultaneous presence of pulses in said first and second signals corresponding to said second coarse home position of said movable element;
- and
- the simultaneous presence of pulses in said one of said first and second signals and said third signal corresponding to said second fine home position of said movable element.
6 more elements
A method of determining a given incremental movement of a movable element from a first fine home position to a second fine home position, comprising:
- generating first and second pulse signals having a number of pulses related to the incremental movement of said movable element between said first fine home position and a second coarse home position, the numbers of pulses in said first and second signals being equal for said incremental movement of said movable element, the widths of the pulses of said first signal being equal to the widths of corresponding pulses of said second signal and corresponding pulses of said first and second signals being substantially out of phase, but not less than by 180.degree.;
- generating a third signal having a number of pulses related to said incremental movement of said element, the number of pulses in said third signal being equal to the number of pulses in said first and in said second signals for said incremental movement of said element, the widths of the pulses of said third signal being less than the widths of the pulses of said first an second signals, and the pulses of said third signal starting before the start of corresponding pulses of one of said first and said second signals and ending before the end of the pulses of said one signal;
- counting the transitions of the pulses of said at least one signal starting with movement of said movable element from said first fine home position, the number of said transitions being related to said incremental movement of said movable member;
- detecting when the number of transitions corresponds to the distance between said first fine home position and second coarse home position;
- detecting the simultaneous presence of pulses in said first and second signals corresponding to said second coarse home position of said movable element;
- and
- detecting the simultaneous presence of pulses in said one of said first and second signals and said third signal corresponding to said second fine home position of said movable element.
4 more elements
Dependencies are inferred from the claim text.