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:
Jul. 07, 1987
Filed:
May. 23, 1984
Walter Schmitt, Traunreut, DE;
Dr. Johannes Heidenhain GmbH, Traunreut, DE;
Abstract
A system for error monitoring in a photoelectric incremental length measuring device for the measurement of the relative position of two objects is described. The measuring device generates at least one measuring signal obtained during the scanning of a scale by means of a scanning unit. This signal is fed simultaneously to an evaluating unit and to an error monitoring unit. In the event of faulty signal parameters of the measuring signal, the error monitoring unit generates an error signal. The measuring signal is applied to an inverter and to a first AND gate. The output of the inverter is applied to a second AND gate. The two AND gates also receive the error signal as a second input. This error signal brings about an in-phase switching of the output signals of the two AND gates. The in-phase state of the signals generated by the AND gates is detected by a phase discriminator of an external evaluating unit, which generates an error signal on a respective line.