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    21.
    发明专利
    未知

    公开(公告)号：DE69222652D1

    公开(公告)日：1997-11-13

    申请号：DE69222652

    申请日：1992-08-20

    Applicant: ROSEMOUNT INC

    Inventor： ANDERSON STEPHEN D ,  FRICK ROGER ,  MONZO GLEN ,  WESTFIELD BRIAN

    IPC: G08C19/02 ,  G08C19/00

    Abstract: A three wire transmitter bidirectionally communicates AC signals to and from a first external device and sends DC signals to a second external device. The transmitter includes a communication circuit which is energized from power and common terminals and includes memory storage for transmitter status and a process variable (PV). The communication circuit receives a sensor output indicative of the PV and provides the DC signal and the AC signal to a signal terminal which connects to both external devices, and also receives AC signals from the first external device. The communications circuit has a characteristic AC impedance between the signal and common terminals over an AC frequency range for receiving and transmitting AC signals to and from the first external device so that the receiving signals are not shorted out and so the transmitted signals can be received. The communications circuit has a characteristic DC impedance between the signal and common terminals over a range of frequencies which include DC and typically extend to approximately 20 Hz. The characteristic impedance is substantially lower than the impedance of the second external device which receives DC signals so that the accuracy of the DC signal is not compromised.

    22.
    发明专利
    未知

    公开(公告)号：DE3751008T2

    公开(公告)日：1995-05-18

    申请号：DE3751008

    申请日：1987-07-14

    Applicant: ROSEMOUNT INC

    Inventor： FRICK ROGER ,  SCHULTE JOHN

    IPC: G01L9/12 ,  G01D5/12 ,  G01D5/24 ,  G01R27/26

    Abstract: A transmitter provides an output representative of a parameter. A generating circuit in the transmitter senses the parameter and provides charge packets having adjustable magnitudes to a measurement circuit. The measurement circuit measures the quantity of charge and provides a measurement signal representing the charge to a feedback circuit. The feedback circuit is controlled by the measurement signal and provides timed feedback signals to the generating means. The feedback signals control the generation and magnitude of the charge packets such that the charge coupled to the measurement circuit is finely balanced in a short measurement interval. The feedback means counts the number of charge packets provided during a measurement interval such that the numbers counted are representative of the sensed parameter.

    23.
    发明专利
    未知

    公开(公告)号：DE3750698T2

    公开(公告)日：1995-05-18

    申请号：DE3750698

    申请日：1987-09-28

    Applicant: ROSEMOUNT INC

    Inventor： FRICK ROGER

    IPC: G01D3/02 ,  G01G7/06 ,  G01G23/01 ,  G01L9/12 ,  G01L19/04 ,  G01G19/413

    Abstract: A transmitter senses a process variable and provides a two-wire output adjusted by a span adjustment. The transmitter has a sensor which senses the process variable and provides a sensor signal. An output circuit provides a two-wire output representative of the sensed process variable. A span-controlling circuit is coupled between the sensor and the output circuit and receives a span adjustment. The span-controlling circuit includes an amplifier coupled to a potentiometer which adjusts the span based on the span adjustment. The wiper of the potentiometer is connected to the amplifier output so that one portion of the potentiometer resistance provides feedback from the amplifier output to the amplifier input. A second portion of the potentiometer resistance is coupled between the amplifier output and the output circuit. Both portions of resistance affect both the span and the resolution of the output. The arrangement provides an improved resolution over a wide turn-down-ratio.

    24.
    发明专利
    未知

    公开(公告)号：DE3853166D1

    公开(公告)日：1995-03-30

    申请号：DE3853166

    申请日：1988-09-23

    Applicant: ROSEMOUNT INC

    Inventor： ORTH KELLY ,  QUIST STEVEN ,  FRICK ROGER ,  PASCHKE RANDY

    IPC: G08C15/06 ,  G01D3/02 ,  G01L9/12 ,  G01L19/06 ,  G01L19/08 ,  G01L27/00 ,  G08C19/02 ,  G08C19/16 ,  H03M1/00

    Abstract: An industrial process control transmitter has a modular construction, with a detector module and an output module electrically connected together by a serial bus. The output module includes a microcomputer, a modem for digital communication over the two-wire loop, analog output circuitry for controlling loop current, a digital-to-analog converter, and a memory for storing calibration factors and D/A characterization factors. The detector module includes several sensors with associated circuitry to convert the sensor signals to digital signals. The detector module also includes a memory which contains characterization factors unique to the sensors which can be used by the microcomputer to correct the digital values provided by the detector circuitry. The microcomputer of the output module is considered the master unit, and all of the circuits of the detector board which interface with the serial bus are considered slave units. Data is collected by the microcomputer when a selected detector circuit provides an interrupt over the serial bus. The microcomputer then provides a select signal requesting data. The detector module provides data from the sensor circuits in a selected order in response to the select signal.

    25.
    发明专利
    未知

    公开(公告)号：DE3751008D1

    公开(公告)日：1995-03-02

    申请号：DE3751008

    申请日：1987-07-14

    Applicant: ROSEMOUNT INC

    Inventor： FRICK ROGER ,  SCHULTE JOHN

    IPC: G01L9/12 ,  G01D5/12 ,  G01D5/24 ,  G01R27/26

    Abstract: A transmitter provides an output representative of a parameter. A generating circuit in the transmitter senses the parameter and provides charge packets having adjustable magnitudes to a measurement circuit. The measurement circuit measures the quantity of charge and provides a measurement signal representing the charge to a feedback circuit. The feedback circuit is controlled by the measurement signal and provides timed feedback signals to the generating means. The feedback signals control the generation and magnitude of the charge packets such that the charge coupled to the measurement circuit is finely balanced in a short measurement interval. The feedback means counts the number of charge packets provided during a measurement interval such that the numbers counted are representative of the sensed parameter.

    26.
    发明专利
    未知

    公开(公告)号：DE3750698D1

    公开(公告)日：1994-12-01

    申请号：DE3750698

    申请日：1987-09-28

    Applicant: ROSEMOUNT INC

    Inventor： FRICK ROGER

    IPC: G01D3/02 ,  G01G7/06 ,  G01G23/01 ,  G01L9/12 ,  G01L19/04 ,  G01G19/413

    Abstract: A transmitter senses a process variable and provides a two-wire output adjusted by a span adjustment. The transmitter has a sensor which senses the process variable and provides a sensor signal. An output circuit provides a two-wire output representative of the sensed process variable. A span-controlling circuit is coupled between the sensor and the output circuit and receives a span adjustment. The span-controlling circuit includes an amplifier coupled to a potentiometer which adjusts the span based on the span adjustment. The wiper of the potentiometer is connected to the amplifier output so that one portion of the potentiometer resistance provides feedback from the amplifier output to the amplifier input. A second portion of the potentiometer resistance is coupled between the amplifier output and the output circuit. Both portions of resistance affect both the span and the resolution of the output. The arrangement provides an improved resolution over a wide turn-down-ratio.

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