Capacitive pressure sensor for a pressure transmitted where electric field emanates substantially from back sides of plates
AssigneeRosemount Inc.
InventorsRoger L. Frick, Bennett L. Louwagie, Adrian C. Toy
Life of this patent
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Abstract
A transmitter in a process control system transmits a pressure over a process control loop. The transmitter includes I/O circuitry, compensation circuitry and an absolute pressure sensor. The I/O circuitry transmits information over the process control loop. Compensation circuitry receives a pressure related signal and responsively controls the I/O circuitry to transmit pressure information on the loop. The absolute pressure sensor includes a cavity which deforms as the sensor deflects in response to an applied pressure. A sensor in the cavity provides the pressure related signal to the compensation circuitry in response to the deformation.
Claims7
A pressure sensor in a pressure transmitter, comprising:
- a pressure responsive structure;
- a first capacitor plate having a back side attached to the pressure responsive structure and a front side;
- a second capacitor plate having a back side attached to the pressure responsive structure and a front side, the first and second capacitor plates positioned to provide relative deflection therebetween in response to pressure applied to the pressure responsive structure;
- and
- wherein the electric field between the first and second capacitor plates emanates substantially between the back sides of the first and second capacitor plates.
Dependencies are inferred from the claim text.