The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Feb. 07, 1984
Filed:
Mar. 03, 1982
Larkin Scott, Forth Worth, TX (US);
William C Muellner, LaGrange Park, IL (US);
The Perkin-Elmer Corporation, Norwalk, CT (US);
Abstract
A direct current servo motor operates through a toothed belt linkage to drive the pen carriage of a chart recorder. The position of the drive is monitored by a sectored encoder disc on the motor shaft. A pair of optical sensors is located relative to the encoder disc to provide alternately phased transition signals as corresponding edges of the encoder disc sectors pass the sensors when the motor rotates. A microprocessor interrupted by a transition signal goes to a sub-routine that determines which way the encoder disc is rotating and stores a count signal of the corresponding sign in a register. Further the microprocessor compares an input signal with the stored count signal and directs the motor to rotate in the direction that will reduce the difference or error signal to zero thus causing the pen to follow the magnitude of the input signal. The sub-routine also computes the rate of error change and applies a correction to motor speed or brakes the motor when the error approaches zero to prevent pen overshoot.