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. 06, 1991
Filed:
Jul. 25, 1988
John E Callan, Milwaukee, WI (US);
Anthony G Gibart, Milwaukee, WI (US);
Kazuaki Kume, Bisai, JP;
Shigeru Ina, Kariya, JP;
Allen-Bradley Company, Inc., Milwaukee, WI (US);
Abstract
A programmable controller includes a number of equipment racks having slots which receive a processor module and a plurality of input/output modules. Each rack has a backplane which includes a number of buses for electrically interconnecting the modules therein, one of these buses carries slot address signals identifying the slot containing an input/output module which the processor module seeks to access. The backplanes of the racks are connected together in a daisy chain. Each backplane has a circuit which responds to the addresses of that rack's slots by producing enable signals for the module in the corresponding slot. This backplane circuit also subtracts the number of slots in its rack from the slot address and passes the result to the next rack in the daisy chain. By this justification of the slot address as it is passed down the daisy chain, each rack address decoder circuit can be hard wired to respond to slot addresses between zero and X, where X is the number of slots in that rack; regardless of the rack's relative position within the daisy chain and the range of virtual addresses for its slots.