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. 05, 1991
Filed:
May. 15, 1989
Scott M Juds, Everett, WA (US);
Opcon, Inc., Everett, WA (US);
Abstract
The operability of a photoelectric sensor is tested by creating both an ON TEST and an OFF TEST. During the ON TEST a test light source, such as a light-emitting diode (LED), located in the vicinity of the light-detecting elements of the photoelectric sensor, is enabled to be energized. Alternatively, the light-detecting elements of the photoelectric sensor are by-passed and the output of the light-detecting elements directly energized. The ON TEST LED (or the by-pass) is interconnected with the circuit that controls the energization of the normal or operational light source(s) of the photoelectric sensor such that the ON TEST LED will only ignite (or the by-pass will only operate) if current flows through the operational light source(s). If the operational light source(s) are damaged and, thus, current cannot flow, the ON TEST LED will not light (or the by-pass will not produce an energizing voltage). A fault is indicated if the sensor output does not indicate the detection of light when the ON TEST is being conducted. In essence, the ON TEST creates (or simulates) light detection regardless of whether an object is located between the operational light source(s) and the light-detecting element(s) of the photoelectric sensor. During the OFF TEST, current flow through the operational light source(s) is inhibited. As a result, the light-detecting elements of the photoelectric sensor do not receive light. A fault indication is provided if the sensor output indicates the detection of light when the OFF TEST is being conducted.