Interchangeable differential, absolute and gage type of pressure transmitter
AssigneeRosemount Inc.
InventorsFred C. Sittler, Stanley E. Rud, Jr., Carl R. Gansen
Life of this patent
Estimating the term…
Abstract
A pressure transmitter with first and second absolute pressure sensors receives process pressures from corresponding first and second process inlets. A transmitter circuit coupled to the first and second absolute pressure sensors generates a differential pressure type output. A third absolute pressure sensor coupled to the transmitter circuit receives atmospheric pressure from a third inlet. The transmitter circuit generates a second type of transmitter output that can be a gage or absolute pressure type. Single crystal. sapphire pressure sensors are preferred to provide enough accuracy for measuring accurately over 200:1 pressure range.
Claims17
An interchangeable pressure transmitter with differential and non-differential outputs, comprising:
- first and second absolute pressure sensors adapted to receive process pressures P1 and P2 from corresponding first and second process inlets;
- a transmitter circuit coupled to the first and second absolute pressure sensors, the transmitter circuit generating a first type of transmitter output that is a first function of differential process pressure F(P2−P1);
- a third absolute pressure sensor coupled to the transmitter circuit, the third absolute pressure sensor being adapted to receive atmospheric pressure P3 from a third inlet different from the first and second process inlets;
- and
- the transmitter circuit generating a second type of transmitter output that is a second function of pressure G(P) different from F(P2−P1).
An interchangeable pressure transmitter with differential and non-differential outputs, comprising:
- two absolute pressure sensors adapted to sense pressures P1 and P2 at process inlets;
- a third absolute pressure sensor adapted to sense atmospheric pressure;
- a transmitter circuit coupled to the three absolute pressure sensors, the transmitter circuit generating differential and non-differential type outputs, such that the transmitter is interchangeable between differential and non-differential installations;
- wherein the transmitter has a two wire, analog 4-20 milliampere output;
- and
- a programming circuit coupled to the transmitter circuit and adapted to receive a programming input selecting either differential or gage type pressure as the 4-20 milliampere output.
Dependencies are inferred from the claim text.