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US 5,606,513 AGranted
Transmitter having input for receiving a process variable from a remote sensor
AssigneeRosemount Inc.
InventorsBennett L. Louwagie, Gregory S. Munson, David E. Wiklund, Michael J. Zweber, David A. Broden, Brian J. Bischoff, Gary P. Corpron
Life of this patent
Estimating the term…
Abstract
A two-wire transmitter senses a pressure using an internal pressure sensor. The transmitter includes an input for receiving a process variable from a remote sensor which is separated from the transmitter. Circuitry in the transmitters transmits information on a two-wire process control loop which is related to the sensed pressure and the process variable.
Claims29
A two-wire transmitter in a process control system for sensing process variables representative of a process, comprising:
- a module housing;
- a pressure sensor coupled to the module housing for sensing a pressure of the process and providing a sensor pressure output;
- a process variable input to the module housing for receiving a process variable signal from an external process variable sensor located outside of a module housing;
- an analog to digital converter coupled to the pressure sensor providing a digital pressure output representative of the sensor pressure output;
- a first microprocessor in the module housing receiving the digital pressure output and providing a compensated output;
- an electronics housing coupled to the module housing;
- a data and power bus coupled to the first microprocessor carrying data and power for the first microprocessor from the electronics housing;
- a second microprocessor in the electronics housing coupled to the data and power bus for receiving the compensated output from the first microprocessor and the process variable signal and responsively calculating a physical parameter related to the process;
- and
- output circuitry coupled to a two-wire process control loop for receiving the calculated physical parameter from the second microprocessor and responsively transmitting the physical parameter on the two-wire process control loop.
7 more elements
A measurement transmitter for use in a process control system for providing the mass flow of a fluid flowing through a pipe, the transmitter communicating over a two-wire circuit, the transmitter comprising:
- a housing;
- sensing means in the housing for sensing process variables representative of a differential pressure and a line pressure;
- means for receiving an input signal from a temperature sensor outside the housing representative of the temperature of the fluid in the pipe;
- analog to digital conversion means in the housing for digitizing the sensed process variables and the input signal;
- electronics means in the housing for providing the mass flow rate of the fluid as a function of the digitized process variables and the digitized input signal, where the electronic means calculates the mass flow rate using a compressibility factor of the form, ##EQU8## output circuitry coupled to the two-wire process control loop for receiving the mass flow rate from the electronics means and transmitting the mass flow rate on the two-wire process control loop;
- and
- circuitry coupled to the two-wire process control loop to receive power from the loop to completely power the transmitter.
4 more elements
A measurement transmitter for use in a process control system for providing the mass flow of a fluid flowing through a pipe, the transmitter communicating over a two-wire circuit, the transmitter comprising:
- a housing;
- sensing means in the housing for sensing process variables representative of a differential pressure and a line pressure;
- means in the housing for receiving an input signal from a temperature sensor outside the housing representative of the temperature of the fluid in the pipe;
- analog to digital conversion means in the housing for digitizing the sensed process variables and the input signal;
- electronics means in the housing for providing the mass flow rate of the fluid as a function of the digitized process variables and the digitized input signal, where the microcomputer means calculates the mass flow using a discharge coefficient of the form, ##EQU9## output circuitry coupled to the two-wire process control loop for receiving the mass flow rate from the electronics means and transmitting the mass flow rate on the two-wire process control loop;
- and
- circuitry coupled to the two-wire process control loop to receive power from the loop to completely power the transmitter.
4 more elements
A pressure measurement transmitter for use in a process control system communicating with a control unit, comprising:
- a transmitter housing having a first pressure port therein;
- a remote housing separated from the transmitter housing having a second pressure port therein;
- a first and second pressure transducer disposed respectively in the first transmitter housing and the remote housing and providing respectively first and second transducer outputs indicative of pressure at the first and second pressure ports;
- circuitry in the remote housing coupled to the second transducer output responsively providing a non-fluidic transducer signal;
- a non-fluidic communication link between the transmitter housing and the remote housing for carrying the non-fluidic pressure signal from the remote housing to the transmitter housing;
- and
- circuitry coupled to the control unit and disposed within the transmitter housing, the circuitry receiving the non-fluidic transducer signal over the non-fluidic communication link and receiving the first transducer output, the circuitry providing a circuitry output to the control unit over a two-wire process control loop as a function of the first and second transducer outputs.
4 more elements
A pressure measurement transmitter in a two-wire process control loop, comprising:
- a transducer housing having a first pressure port and a first communication port;
- a transmitter housing having a second pressure port and a second and third communication port;
- a first and a second pressure transducer disposed respectively in the transducer housing and the transmitter housing and providing respectively a first and second electrical output responsive to pressure at respectively the first and second pressure port;
- calculation circuitry disposed in the transmitter housing and coupled to the first electrical output through the first communications port and the second communications port and to the second electrical output, the calculation circuitry calculating a parameter related to pressures at the first and second pressure ports and providing a third electrical output indicative of the parameter;
- and
- output circuitry disposed in the transmitter housing transmitting the calculate parameter over the two-wire process control loop through the third communication.
3 more elements
A transmitter in a two-wire process control loop for measuring a pressure of a process fluid, comprising:
- a transmitter housing having a pressure port and a first and second electrical port;
- a pressure transducer disposed in the transmitter housing and communicating with the pressure port, the pressure transducer providing an electrical output as a function of the process fluid pressure at the pressure port;
- means disposed in the transmitter housing for receiving at the first electrical port an external electrical output indicative of the process fluid pressure at a remote pressure port external to the transmitter housing;
- calculation electronics disposed in the transmitter housing and coupled to the receiving means and to the electrical output, the calculation electronics calculating as a function of the external electrical output and the electrical output another pressure of the process fluid;
- and
- output circuitry in the transmitter housing for transmitting the other pressure over the two-wire process control loop.
3 more elements
Dependencies are inferred from the claim text.