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:
Jan. 15, 1980
Filed:
Feb. 15, 1978
Hitachi, Ltd., both of, JP;
Nissan Motor Company, Limited, both of, JP;
Abstract
A method and an apparatus for diagnosing a fault in a sequence control system performing control in accordance with a predetermined sequence, wherein memory means having bits corresponding to respective ones of a plurality of predetermined sequence steps is provided. The sequence of steps actually applied to an object to be controlled are sequentially stored in corresponding bits. Each time a sequence step is applied to the object to be controlled, the contents of the memory means are checked to see whether or not any of the sequence steps applied thus far have been skipped. If any sequence step has been skipped, a fault is determined. Preferably, a fault is also determined when any of the intervals of sequence steps successively applied exceeds a predetermined length of time. Upon determination of a fault, the sequence step associated with the fault is identified, and the control circuit associated with the sequence step in fault is preferably displayed.