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:
Jun. 06, 1989
Filed:
Apr. 04, 1988
Dick E Davis, Arlington, TX (US);
Charles R Brazell, Arlington, TX (US);
Jerome E Johnston, Austin, TX (US);
General Electrodynamics Corporation, Arlington, TX (US);
Abstract
A platform weighing system (10) suitable for making accurate weight measurements of heavy objects, such as aircraft, is disclosed. Hardware and software combine to produce the accurate results. Analog hardware (14) includes hydraulic load cells (80a-80d), temperature sensing (91), filtering (90), and voltage-to-frequency conversion (104). Digital hardware (12) receives an oscillation signal output from the voltage-to-frequency conversion (104) and obtains load counts by monitoring the oscillation signal for consistent predetermined durations. The predetermined duration is chosen in software (226) to be immune to particularly pervasive noise signals. A microprocessor (16) converts load counts into a weight code which is output to a display (46). This conversion includes compensation for auto ranging (320), load cell excitation variance (282), temperature compensation (284), null offset variance (286), and zero drifting (304). In addition, nonlinearities in load cell output are compensated by linearly interpolating (288-296) between two of a plurality of calibration points that characterize the load cells (80a-80d ). Such compensations are performed primarily in software (200).