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:
May. 31, 1977
Filed:
Apr. 23, 1976
Ronald Jon Marosko, Houston, TX (US);
TRW Inc., Redondo Beach, CA (US);
Abstract
A multiplexed data monitoring system for use in monitoring the status of control valves or the like in subsea petroleum well control systems, utilizes an encoder circuit located externally of the control module and composed of passive electrical components, such as inductors and capacitors, to encode switch contact closure or status information into discrete frequency data. The external encoder circuit is coupled by a pair of wires to the control module. The decoder circuitry within the subsea control module applies an alternating current signal of varying frequency to the encoder circuit and by monitoring the phase of the alternating current, the decoder circuitry can recover the data impressed by the switch contacts at the status points, which are also located externally of the control module.