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:
Aug. 02, 1994
Filed:
Aug. 12, 1991
John F Crooks, Cambridge, OH (US);
Robert L Protheroe, Cambridge, OH (US);
NCR Corporation, Dayton, OH (US);
Abstract
An automatic fault detection apparatus which requires no human intervention. The apparatus includes a source for energizing the digitizer including a constant direct current source and a constant direct voltage source, and a switch for selectively coupling either the constant current source or the constant voltage source to the digitizer. An analog-to-digital converter couples to the digitizer and to the source. A controller couples to the output of the analog-to-digital converter. Switches selectively connect the source and the analog-to-digital converter to the digitizer and include analog switches controlled by the controller. A non-volatile memory couples to the controller. An indicator coupled to the controller provides information about digitizer operability. A plurality of test electrodes within the digitizer couple to the analog-to-digital converter. Finally, a wiring harness connects the analog-to-digital converter and the source to the digitizer. The apparatus couples to operative electrodes within the digitizer. The method of the present invention includes four tests for detecting faults within digitizers.