公开(公告)号：CA2178809A1

公开(公告)日：1995-07-27

申请号：CA2178809

申请日：1995-01-17

Applicant: ROSEMOUNT INC

Inventor： WARRIOR JOGESH ,  BRIGHAM SCOTT E ,  LENZ GARY A

IPC: G01D3/028 ,  G01D3/02 ,  G01D3/036 ,  G01D18/00

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).

公开(公告)号：CA2231733A1

公开(公告)日：1998-02-12

申请号：CA2231733

申请日：1997-07-11

Applicant: ROSEMOUNT INC

Inventor： ZOU HEHONG ,  BRIGHAM SCOTT E

IPC: G05B13/04

Abstract: A process control system (100) controls a non-self regulating process through a control output signal (u(t)) based on a set point YSET and a measured process variable (y(t)). The process control system includes a control circuit (102, 104, 106, 108) having a set point input, a process variable input and a control output. The control circuit generates the control output signal (u(t)) on the control output as a function of the set point YSET received on the set point input and the measured process variable (y(t)) received on the process variable input. An auto-tuning circuit (106) excites the process, estimates a process model based on an intersection between rising and falling asymptotes of the measured process variable (y(t)), and then tunes the control function to the process (110) based on the process model. The auto-tuning circuit obtains robust results, but is computationally simple such that the circuit can be implemented with hardware or software in low-power and low-memory applications, such as in field-mounted controllers.

公开(公告)号：BR9506548A

公开(公告)日：1997-08-19

申请号：BR9506548

申请日：1995-01-17

Applicant: ROSEMOUNT INC

Inventor： WARRION JOGESH ,  BRIGHAM SCOTT E ,  LENZ GARY A

IPC: G01D3/028 ,  G01D3/02 ,  G01D3/036 ,  G01D18/00

Abstract: A circuit for compensating variables in a measurement transmitter. Within the transmitter, a sensor senses a primary process variable such as differential pressure and a converter digitizes the sensed process variable. The sensor senses pressures within a span of pressures values. A memory inside the transmitter stores at least two membership functions, each membership function having a non-zero value over a predetermined region of the process variable span and a substantially zero value over the remainder of the span. The memory also stores a set of compensation formulas, each formula corresponding to a membership function. A selection circuit in the transmitter selects those membership functions which have a non-zero value at the digitized process variable and a correction circuit provides at least one correction value, each correction value calculated from a compensation formula corresponding to a selected membership function. A weighting circuit multiplies each correction value by its corresponding selected membership function, and combines the multiplicands to provide a compensated process variable. The compensated process variable is coupled to a control circuit connecting the transmitter to a control system.

公开(公告)号：MX9602017A

公开(公告)日：1997-05-31

申请号：MX9602017

申请日：1995-01-17

Applicant: ROSEMOUNT INC

Inventor： WARRIOR JOGESH ,  LENZ GARY A ,  BRIGHAM SCOTT E

IPC: G01D3/028 ,  G01D3/02 ,  G01D3/036 ,  G01D18/00 ,  G01D03/02 ,  G01D03/028

Abstract: Un circuito (58) para compensar las variables en un transmisor (2) de medicion. Dentro del transmisor, un censor (54) detecta una variable del proceso primaria tal como una presion diferencial, y un convertidor (56) digitiza la variable del proceso detectada. El censor (54) detecta las presiones dentro de un lapso de valores de presiones. Una memoria (68) dentro del transmisor almacena por lo menos dos funciones de afiliacion. La memoria (68) también almacena un juego de formulas de compensacion, cada formula corresponde a una funcion de afiliacion. Un circuito (64) de seleccion en el transmisor (2) selecciona aquellas funciones de afiliacion que tienen un valor que no es de cero en la PV digitizada, y un circuito (66) de correccion proporciona por lo menos un valor de correccion calculado de una formula de compensacion que corresponde a una funcion de afiliacion seleccionada. Un circuito (70) de ponderacion multiplica cada valor de correccion mediante su funcion de afiliacion seleccionada correspondiente, y combina los multiplicandos para proporcionar una PV compensada. La PV compensada se acopla a un circuito (6) de control que conecta el transmisor (2) con un sistema (4) de control.