Interchangeable differential, absolute and gage type of pressure transmitter
First Claim
1. 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).
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Accused Products
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.
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Citations
17 Claims
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1. An interchangeable pressure transmitter with differential and non-differential outputs, comprising:
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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).- View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
a selection circuit coupled to the transmitter circuit and adapted to receive a command setting the multipliers A, B and C for the second transmitter output.
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5. The pressure transmitter of claim 3 wherein the command can select the second function from the group G(P1), G(P2), G(P3), G(P1−
- P3), G(P2−
P3).
- P3), G(P2−
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6. The pressure transmitter of claim 1 wherein the pressure transmitter has a two wire, analog 4-20 milliampere output and the transmitter further comprises:
a programming circuit coupled to the transmitter circuit and adapted to receive a programming input selecting either the first transmitter output or the second transmitter output as the 4-20 milliampere output.
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7. The pressure transmitter of claim 6 wherein the transmitter circuit generates multiple transmitter outputs that are labeled serial representations adapted for transmission to a receiver that can distinguish the outputs by the labels, the multiple transmitter outputs representing differential pressure (P2−
- P1), absolute pressure P1, absolute pressure P2, atmospheric pressure P3, gage pressure (P1−
P3) and gage pressure (P2−
P3).
- P1), absolute pressure P1, absolute pressure P2, atmospheric pressure P3, gage pressure (P1−
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8. The pressure transmitter of claim 1 wherein the first and second transmitters outputs are labeled first and second serial representations adapted for transmission to a receiver that can distinguish between the first and second outputs by the labels.
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9. The pressure transmitter of claim 8 wherein the serial representations are formatted for transmission via a process control network.
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10. The transmitter of claim 1, further comprising:
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a manifold coupled to the first, second and third inlets and including a valve actuatable to couple the first, second and third inlets to each other; and
a diagnostic circuit coupled to the transmitter circuit and setting an alarm if the first, second and third pressures are not substantially equal to one another after actuation of the valve.
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11. The pressure transmitter of claim 1 wherein the first, second and third pressure sensors are integrally formed of sapphire.
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12. The pressure transmitter of claim 11 having a specified range of accurate pressure measurement that is more than 200:
- 1.
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13. The pressure transmitter of claim 1 wherein the transmitter circuit further comprises majority voting logic to provide a second transmitter output which is an absolute pressure sensed by at least two of the first, second and third absolute pressure sensor.
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14. An interchangeable pressure transmitter with differential and non-differential outputs, comprising:
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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. - View Dependent Claims (15, 16, 17)
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Specification