Abstract: A two-wire transmitter senses differential pressure, absolute pressure, and process temperature of a process fluid. The information can be used to provide an output representative of mass flow through a pipe. The transmitter has an electronics module housing attached to a sensor module housing. The sensor module housing contains all the sensors for the pressures and includes a boss input for receiving a signal representative of a temperature or pressure signal. The three process variables are appropriately digitized, and received by an electronics circuit board in the electronics housing including a microprocessor for calculating the mass flow. The microprocessor in the electronics housing also calculates a compressibility factor and a discharge coefficients according to a polynomials of specific forms. The boss is integral to the sensor module housing and is adapted to fit either shielded twisted pair cabling or conduit.

Abstract: A master transmitter couples to first and second slave units through a bus. The slave units provide outputs to the bus related to first and second pressures of a process. The bus provides power to the units and carries signals. The master transmitter is adapted to couple to a two-wire process control loop which wholly powers the system.

Abstract: A transmitter of the type used in the process control industry includes a sensor for sensing a process variable and a transmitter body having a sensor coupling. A sensor extension couples to the sensor coupling and includes a sensor coupling face. A first flange interface has a process face which provides a process connection and a sensor face which provides a sensor connection. A passageway couples the process connection to the sensor connection. The first flange interface is coupled to the sensor extension by a coupling mechanism. The sensor extension and the first flange interface may be moved throughout, a range of positions relative to one another.

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.

Abstract: In this invention, a multivariable transmitter providing an output representative of mass flow has a dual microprocessor structure. The first microprocessor compensates digitized process variables and the second microprocessor computes the mass flow as well as arbitrating communications between the transmitter and a master. In a second embodiment of the present invention, a first microprocessor compensates digitized process variables, a second microprocessor computes an installation specific physical parameter such as mass flow and a third microprocessor arbitrates real-time communications between the transmitter and a master.

Abstract: A transmitter with a flame arresting header senses a pressure of a process fluid with a diaphragm which is sealed to the header. The diaphragm transfers the pressure of the process fluid acting an outer surface of the diaphragm to a fill fluid that isolates an inner surface of the diaphragm, and a pressure sensor enclosed in the transmitter senses the pressure of the fill fluid providing an output representative of the pressure of the process fluid. The header includes a chamber on the header's outer face and a passageway extending from the chamber to a tapered opening inside the transmitter with a first portion adjacent to the tapered opening shaped to receive an inlet tube leading to the sensor and a second flame isolating portion open to the chamber. The fill fluid fills the chamber, the passageway, and the inlet tube and is sealed in with a tapered seal pressed into the tapered opening around the inlet tube.

Abstract: A metal thin film bonds a semiconductor bonding region of a diaphragm layer to a ceramic bonding region of a high modulus support block. The arrangement isolates a pressure sensing diaphragm from undesired strain, improving sensor accuracy. A passageway through the support block couples the fluid pressure to the sensing diaphragm to deflect it. Capacitive coupling between the diaphragm and a capacitor plate on the support block sense the deflection and provide an output representative of pressure.

Abstract: A transmitter provides an output that is indicative of pressure and has two modular transmitter bodies, one including a sensor, and the other having an isolator diaphragm with a substantially non-compressible fluid that transfers movement of the isolator diaphragm to the sensor. The bodies each have mating passageways to transfer non-compressible fluid from one body to the other and are assembled together using a ring of extrusile material disposed around the mating portions of the passageways to seal the passageways together when the transmitter bodies are assembled. The isolation fluid is filled in the passageway of the bodies before the first and second transmitter bodies are assembled. The assembly can be accomplished without complex procedures and still insure that accurate transmitter operation will be obtained.

Abstract: A sensing cell for sensing pressures which includes a housing and a diaphragm that deflects relative to a housing surface under pressure differentials, the movement of the diaphragm is sensed to provide indications of pressure changes. The diaphragm has a center disc like deflecting portion, an outer peripheral support ring that is clamped for supporting the diaphragm in a housing, and an integral, reduced section web joining the center portion and the support ring. The reduced cross section web causes the diaphragm to act as a free edge diaphragm during deflection. The housing and/or the diaphragm are configured so that at near a rated overpressure stop means support the central disc portion at its annular edge where the web joins the central disc portion to reduce the maximum stress on the web and thus prevent over stressing of the web portion of the diaphragm under maximum overpressures, to reduce hysteresis and innaccuracies.