Abstract:
A temperature transmitter (10) and a process control system includes a sensor input (1, 2, 3, 4) for coupling to a temperature sensor (16) having a temperature dependent resistance. Resistance measuring circuitry (20, 26, 50) couples to the sensor input (1, 2, 3, 4) and provides a resistance output related to resistance of the temperature dependent resistance. Analog to digital conversion circuitry (78, 88) couples to the sensor input (1, 2, 3, 4) and provides a digital output related to AC signals across the sensor input. Digital signal processing circuitry (64) isolates a Johnson noise component of the AC signals and provides a digitized Johnson output. Temperature measurement circuitry provides a calibrated temperature output based upon the resistance output and the digitized Johnson noise output. Output circuitry (24) transmits the calibrated temperature output over the process control loop (11).
Abstract:
A system for transmitting optical power from a first location to a second location. The system includes a first light source (108) at the first location which generates a first light beam. A power converter (200) detects the first light beam at the second location. A first control circuit (20) coupled to the power converter operates a second light source (200) at the second location to generate a return safety light beam after detection of the first light beam. A photodetector (116) detects the return safety light beam at the first location. A second control circuit is coupled between the photodetector (116) and the first light source (108). The second control circuit detects the presence of the return safety light beam and operates the first light source (108) to generate the first light beam at a first power level prior to detecting the return safety light beam and at a second power level, higher than the first power level, after detecting the return safety light beam.
Abstract:
A process controller (100) controls an integrating-type process (112) based on a measured process variable (y(t)) and a set point (Y>SET SET SET
Abstract translation:过程控制器(100)基于测量的过程变量(y(t))和设定点(Y> SET <)来控制积分型过程(112)。 过程控制器(100)包括误差产生电路(102),非积分控制电路(104)和自适应偏置电路(108)。 误差产生电路(102)基于设定点(Y> SET <)和测量过程变量(y(t))之间的差异产生误差信号(e(t))。 控制电路(104)产生作为误差信号(e(t))的函数的控制信号(u(t))。 自适应偏置电路(108)向控制信号(u(t)),测量过程变量(y(t))或设定点(Y> SET <)添加偏置值。 作为误差信号(e(t))的函数选择性地更新偏置值,以迫使误差信号(e(t))朝向零。
Abstract:
A level transmitter (10) for use in a process application measures height of a product (14) in a tank (12). The level transmitter (10) includes a microwave antenna (18) directed into the tank (10). A low power microwave source (70) sends a microwave signal through the microwave antenna (18). A low power microwave receiver (70) receives a reflected microwave signal. Measurement circuitry (42) coupled to the source and receiver initiates transmitting of the microwave signal and determines product height based upon the received, reflected signal. Output circuitry (48, 56) coupled to a two-wire process control loop (20) transmits information related to product height over the loop (20). Power supply circuitry (40) in the level transmitter (10) coupled to the two-wire process control loop (20) receives power from the loop (20) which powers the level transmitter (10) including the microwave source and the microwave receiver (70).
Abstract:
The present invention relates to a mounting assembly (21) for a pressure sensor (30) in a pressure transmitter (10). The mounting assembly (21) includes a header (58) having a cavity (32) opening to a first surface (103). The cavity (32) is defined by an inner endwall (164) and an inner sidewall (130). A support (120) is joined to the inner endwall (164) within the cavity on a first support end (150). A pedestal (102) has a first pedestal end (102A) supporting the pressure sensor (30) and a second pedestal end (102B) joined to a second support end (136). Aligning means (132) align the second pedestal end (102B) to the second support end (136) in order that a volume of the mounting assembly (21) is increased to thereby reduce a quantity of fill fluid needed in the sensor cavity (32).
Abstract:
A pressure or flow transmitter (11) having a pressure sensor (27) disposed in a transmitter housing (14). The pressure transmitter (11) includes a diaphragm (18) remote from the pressure sensor (27). The diaphragm (18) is connected to the pressure sensor (27) with capillary tubing (22) containing a fluid. The diaphragm (18) is disposed at a relative vertical position (H) from the transmitter housing (14). The transmitter (11) contains circuitry (58, 60, 62, 64) which provides a transmitter output as a function of the pressure output, the circuitry (58, 60, 62, 64) adjusts the transmitter output as a function of the relative vertical position (H) of the diaphragm (18).
Abstract:
First capacitance pressure sensor (70A, B) has a fusion bonded single crystal structure (sapphire with cavity). Second one (70A, B) has an elongated and thick single crystal structure. Third one (70A, B) uses the electric field emanating from the back sides of the capacitor plates. First differential pressure transmitter uses a process barrier (71) and an elongated member as a sensor (70A, B). Second differential pressure transmitter uses single crystal structures with stress isolation members as sensors (70A, B). Basically thick slab cavity capacitance sapphire sensors are directly exposed to a process fluid. Slab: 15x3x2 cubic mm, cavity cross section: 1mm x 0.5 micro m, capacitance: 42 pF.
Abstract:
A magnet (16) mounted on a moving stem (12) or rotary member of a valve generates magnetic flux over part of a stationary member (14) of the valve which has a uniquely patterned set of magnetoresistive sense resistors (RSIG0-RSIG4) and three reference resistors (130, 134, 148) disposed thereon. The distance between two adjacent patterns can be equally spaced, or can be compressed for valves with non-linear characteristics in order to achieve increased resolution over a specific portion of the valve travel. Other embodiments can use a light source, beta radiation or neutron radiation as the source of flux, the pattern for each embodiment's sensor having some material responsive and some unresponsive to the flux. The sensor (18) can provide feedback representative of position in a valve positioner, or functions as the position sensor in a position transmitter.
Abstract:
A circuit (58) for compensating variables in a measurement transmitter (2). Within the transmitter, a sensor (54) senses a primary process variable such as differential pressure and a converter (56) digitizes the sensed process variable. The sensor (54) senses pressures within a span of pressures values. A memory (68) inside the transmitter stores at least two membership functions. The memory (68) also stores a set of compensation formulas, each formula corresponding to a membership function. A selection circuit (64) in the transmitter (2) selects those membership functions which have a non-zero value at the digitized PV, and a correction circuit (66) provides at least one correction value calculated from a compensation formula corresponding to a selected membership function. A weighting circuit (70) multiplies each correction value by its corresponding selected membership function, and combines the multiplicands to provide a compensated PV. The compensated PV is coupled to a control circuit (6) connecting the transmitter (2) to a control system (4).
Abstract:
In this invention, a multivariable transmitter (2) providing an output representative of mass flow has a dual microprocessor structure. The first microprocessor (72) compensates digitized process variables and the second microprocessor (80) computes the mass flow as well as arbitrating communications between the transmitter (2) and a master (88).