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:
Apr. 16, 1996
Filed:
Sep. 26, 1994
Robert L Diehl, Garland, TX (US);
Forney International, Inc., Carrollton, TX (US);
Abstract
In a distributed logic control system, two duplicate analog I/O boards are provided to provide redundancy for the analog I/O boards. The analog I/O boards serve the function of applying analog output signals corresponding to received digital signals from a data processor to analog signal responsive units. Each analog I/O board has a microprocessor and two digital-to-analog converters and a analog-to-digital converter. The microcomputer determines whether the analog output signals generated by the digital-to-analog converters are within limits and, if they are not, it generates a fail signal applied to a programmable array logic circuit. Each analog I/O board includes a watch dog timer to indicate the sanity of the analog I/O board. The programmable array logic circuits respond to the failure conditions indicated by the watch dog timer and the microcomputer to select one of the analog I/O boards to be the operating analog I/O board to provide analog signals to analog signal responsive units.