Multivariable transmitter and computation processing method of the same

• US 7,584,063 B2
• Filed: 12/03/2004
• Issued: 09/01/2009
• Est. Priority Date: 12/05/2003
• Status: Active Grant

• Current Assignee: Yokogawa Electric Corporation
• Original Assignee: Yokogawa Electric Corporation
• Inventors: Ito, Akio, Nakagawa, Masaru, Koyama, Etsutaro, Suzuki, Atsuko
• Primary Examiner(s): Cosimano; Edward R
• Assistant Examiner(s): Le; Toan M
• Application Number:
  US11/004,025
• Publication Number:
  US 20050125190A1
• Time in Patent Office: 1,733 Days
• Field of Search: 702/47, 702/50, 702/56, 702/127, 702/138, 702/33, 702/45, 702/52, 702/53, 702/54, 702/189, 737/18, 738/610.3, 738/610.2, 738/611.8, 737/00, 737/02, 737/04, 737/15, 737/16, 737/20, 737/21, 73/11.6, 73/13.5, 73/15.7, 73/37, 731/521.8, 731/522.1, 731/522.9, 738/61, 738/614.2, 738/614.3, 738/614.7, 310/338, 310/314, 310/321, 310/324, 375/295, 700/282, 700/301, 377/21, 137/557
• US Class Current: 702/47
• CPC Class Codes: G01D 1/00 Measuring arrangements giving results other than momentary value of variable, of general application G01D3/00 takes precedence; in tariff metering apparatus G01D4/00; transducers not specially adapted for a specific variable G01D5/00
• CPC Class Codes: G01F 1/50 Correcting or compensating means
• CPC Class Codes: G01F 15/024 involving digital counting

Abstract

A multivariable transmitter has a microprocessor for executing a computation processing task such as calculating a differential pressure value and static pressure with using a plurality of physical quantity signals. The microprocessor executes a processing for obtaining data from a sensor every computation processing task and executes the computation processing task in a time-division manner.

Claims

1. A multivariable transmitter comprising:

a single microprocessor for executing a plurality of computation processing tasks using a plurality of physical quantity signals; and

an output section for outputting an output of said multivariable transmitter,

wherein the single microprocessor executes the plurality of computation processing tasks in a time-division manner, wherein every computation processing task is not executed during every computation processing period, such that high priority computation processing tasks are executed more frequently than low priority computation processing tasks, the computation processing tasks include a computation processing task for calculating a differential pressure value and a static pressure value of a fluid to be measured, and a flow rate computation processing task based on the differential pressure value, the static pressure value and a temperature value of the fluid to be measured; and

wherein

the computation processing tasks include a computation selecting processing which selects a processing item to be executed during each computation period, and a process temperature value computation processing task to be divided and executed through a plurality of computation periods, and

the temperature value of the fluid to be measured is a process temperature with respect to the fluid to be measured.

2. The multivariable transmitter according to claim 1,

wherein the computation processing tasks include a communication processing computation task for transferring physical quantity data or computed data to a higher equipment by means of communication and obtaining various types of data from the higher equipment.

3. The multivariable transmitter according to claim 2,

wherein a sensor for detecting the physical quantity is a resonant-type pressure sensor which has a single pressure sensitive diaphragm and detects differential pressure and static pressure by means of computation.

4. The multivariable transmitter according to claim 3,

wherein the sensor is a resonant-type pressure sensor which outputs a first resonance frequency and a second resonance frequency.

5. The multivariable transmitter according to claim 4, further comprising:

a resistance temperature sensor provided in an atmosphere of a process temperature; and

a nonvolatile data table for storing resistance values of the resistance temperature sensor and temperature values corresponding to the resistance values,

wherein the microprocessor calculates a temperature value by an interpolation computation based on the resistance values and the data table.

6. The multivariable transmitter according to claim 5,

wherein the resistance values are formed at intervals in the data table, and a linear interpolation equation is used for the interpolation computation.

7. A computation processing method of a multivariable transmitter which executes a plurality of computation processing tasks using a plurality of physical quantity signals, comprising the steps of:

setting a computation selection switch which assigns a computation selection and a division processing;

executing a processing for obtaining data from a sensor;

executing a processing when a computation is executed by the computation selection switch;

outputting an output of said multivariable transmitter;

selecting a processing item to be executed during each computation period;

dividing and executing a computation processing task through a plurality of computation periods such that every computation processing task is not executed during every computation processing period, such that high priority computation processing tasks are executed more frequently than low priority computation processing tasks;

calculating a differential pressure value and a static pressure value of a fluid to be measured; and

executing the computation processing tasks using a flow rate computation processing task based on the differential pressure value, the static pressure value and a temperature value of the fluid to be measured.