US 5,119,679 AGranted

Optically powered and linked pressure transducer

AssigneeThe Boeing Company

InventorIsrael Frisch

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Abstract

A pressure sensing system that is relatively immune to EMI. The system comprises a sensor and a controller linked to one another by a fiber optic cable. The sensor includes an electronic pressure transducer, and means for converting an optical power signal received from the controller via the fiber optic cable into DC electrical power for the transducer. The transducer produces an electronic output signal that encodes the pressure, and this output signal is converted into a corresponding optical output signal that is transmitted to the controller along the fiber optic cable. A preferred pressure transducer is a vibrating crystal pressure transducer, the output signal of which is converted to electronic form at the controller, and demodulated by a counter. The power signal is preferably a time invariant, and not a function of the output signal.

Claims10

Dependent claims

A pressure sensing system adapted for use in an EMI environment, the system comprising:

(a) an EMI shielded sensor comprising:
(i) an electronic pressure transducer, the pressure transducer comprising means for receiving a fluid whose pressure is to be sensed, means for receiving DC electrical power, and means for producing an electronic output signal having a characteristic that encodes the pressure of said fluid;
(ii) first conversion means including means for receiving an optical power signal, means for converting the optical power signal into said DC electrical power, and means for coupling said DC electrical power to the pressure transducer;
and
(iii) second conversion means including means for receiving the electronic output signal and means for converting the electronic output signal into a corresponding optical output signal;
(b) an EMI shielded controller comprising:
(i) means for generating the optical power signal;
and
(ii) means for receiving the optical output signal;
and
(c) fiber-optic cable means for coupling the optical power signal from the controller to the sensor and for coupling the optical output signal from the sensor to the controller.

8 more elements

Dependencies are inferred from the claim text.

Facts

Application: 07/681,854Filed 5 Apr 1991
Granted: 9 Jun 1992
Term ends: Not estimatedThe source records don’t support an estimate.

Classification7 codes

G01L 11/02
Measuring steady or quasi-steady pressure of a fluid or a fluent solid material by means not provided for in group G01L7/00 or G01L9/00: by…
G01D 5/26
Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where…:…
G01D 5/268
Characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light: using optical fibres
G01L 9/0023
Of a piezoelectric element: optical excitation or measuring