Rosemount Inc.

David Richard Lauzon

Steven John McCoy

Scott Robert Thompson

A remote seal system includes a remote diaphragm having a first side configured to be exposed to a process fluid. A conduit is coupled to the remote diaphragm and includes a fill fluid in fluidic communication with a second side of the remote diaphragm. A temperature sensor is thermally coupled to the conduit and configured to sense a temperature of the fill fluid. In one alternative example, a remote sensing assembly includes a flexible elongate conduit having a first end coupled to a remote diaphragm in fluidic communication with a process fluid and a second end extending a length from the first end to a process fluid pressure transmitter. A substantially incompressible fill fluid is disposed within the flexible elongate conduit. The process fluid pressure transmitter is configured to generate an output value indicative of pressure in the process fluid based on a corresponding pressure in the fill fluid. A temperature detector is coupled to the flexible elongate conduit and is configured to provide a signal indicative of an average temperature of the fill fluid along the flexible elongate conduit. A compensation system calculates a thermal expansion value based on the average temperature and adjusts the pressure signal based on the thermal expansion value.

Remote seal system with improved temperature compensation

A two-wire process variable transmitter for use in an industrial process includes a process variable sensor configured to sense a process variable of a process fluid of the industrial process. Output circuitry provides an output on a two-wire process control loop which is related to the sensed process variable. Terminal voltage measurement circuitry measures a voltage at terminals of the process variable transmitter. The terminal voltage is a voltage measured across an electrical connection of the two-wire process variable transmitter to the two-wire process control loop. A microprocessor performs loop diagnostics on the two-wire process control loop based upon a loop current and the measured terminal voltage. The microprocessor determines coefficients of a polynomial equation which relates loop current and terminal voltage during normal operation of the two-wire process variable transmitter and performs subsequent diagnostics based upon the coefficients of the polynomial.

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Hopkins, MN, United States of America

David Richard Lauzon