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. 14, 1978
Filed:
Jun. 03, 1976
Mutsuaki Nakagawa, Musashino, JA;
Yutaka Wakasa, Musashino, JA;
Hisayuki Uchiike, Musashino, JA;
Susumu Nagata, Musashino, JA;
Yokogawa Electric Works, Ltd., Tokyo, JA;
Abstract
A process control system of the type arranged to accept sensing signals from field sensing devices, to digitally process data represented thereby, and to supply control signals to field control devices. The system is characterized by a centralized maintenance backup system for supplying backup control signals to selected field control devices while their normal control signals are interrupted during servicing of various system components, e.g., signal conversion units. A maintenance backup device, centrally located at a control station, includes means for providing an adjustable backup control signal, a selector unit having jack terminals connected through prewired leads to a plurality of field control devices, and jack plug means for connecting the backup control signal means to a selected jack terminal and the field control device corresponding thereto. Servicing of circuit boards used, e.g., for signal conversion purposes, is facilitated by providing ready and simplified access to the different field control devices through the selector unit, and by utilizing data available at the system's central operating location to continue control of the field device in the manner prescribed by the digital processing unit.