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WO2009033845A1 - Dispositif de détermination et/ou de surveillance d'une variable d'un processus - Google Patents

Dispositif de détermination et/ou de surveillance d'une variable d'un processus Download PDF

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Publication number
WO2009033845A1
WO2009033845A1 PCT/EP2008/058970 EP2008058970W WO2009033845A1 WO 2009033845 A1 WO2009033845 A1 WO 2009033845A1 EP 2008058970 W EP2008058970 W EP 2008058970W WO 2009033845 A1 WO2009033845 A1 WO 2009033845A1
Authority
WO
WIPO (PCT)
Prior art keywords
measuring
measuring branch
unit
branch
electronic
Prior art date
Application number
PCT/EP2008/058970
Other languages
German (de)
English (en)
Inventor
Thomas Schönstein
Original Assignee
Innovative Sensor Technology Ist Ag
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Innovative Sensor Technology Ist Ag filed Critical Innovative Sensor Technology Ist Ag
Publication of WO2009033845A1 publication Critical patent/WO2009033845A1/fr

Links

Classifications

    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01D—MEASURING NOT SPECIALLY ADAPTED FOR A SPECIFIC VARIABLE; ARRANGEMENTS FOR MEASURING TWO OR MORE VARIABLES NOT COVERED IN A SINGLE OTHER SUBCLASS; TARIFF METERING APPARATUS; MEASURING OR TESTING NOT OTHERWISE PROVIDED FOR
    • G01D18/00—Testing or calibrating apparatus or arrangements provided for in groups G01D1/00 - G01D15/00
    • G01D18/002—Automatic recalibration
    • G01D18/004—Continuous recalibration
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01D—MEASURING NOT SPECIALLY ADAPTED FOR A SPECIFIC VARIABLE; ARRANGEMENTS FOR MEASURING TWO OR MORE VARIABLES NOT COVERED IN A SINGLE OTHER SUBCLASS; TARIFF METERING APPARATUS; MEASURING OR TESTING NOT OTHERWISE PROVIDED FOR
    • G01D21/00—Measuring or testing not otherwise provided for
    • G01D21/02—Measuring two or more variables by means not covered by a single other subclass
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01K—MEASURING TEMPERATURE; MEASURING QUANTITY OF HEAT; THERMALLY-SENSITIVE ELEMENTS NOT OTHERWISE PROVIDED FOR
    • G01K15/00—Testing or calibrating of thermometers
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01K—MEASURING TEMPERATURE; MEASURING QUANTITY OF HEAT; THERMALLY-SENSITIVE ELEMENTS NOT OTHERWISE PROVIDED FOR
    • G01K7/00—Measuring temperature based on the use of electric or magnetic elements directly sensitive to heat ; Power supply therefor, e.g. using thermoelectric elements
    • G01K7/16—Measuring temperature based on the use of electric or magnetic elements directly sensitive to heat ; Power supply therefor, e.g. using thermoelectric elements using resistive elements
    • G01K7/18—Measuring temperature based on the use of electric or magnetic elements directly sensitive to heat ; Power supply therefor, e.g. using thermoelectric elements using resistive elements the element being a linear resistance, e.g. platinum resistance thermometer
    • G01K7/20—Measuring temperature based on the use of electric or magnetic elements directly sensitive to heat ; Power supply therefor, e.g. using thermoelectric elements using resistive elements the element being a linear resistance, e.g. platinum resistance thermometer in a specially-adapted circuit, e.g. bridge circuit
    • G01K7/203—Measuring temperature based on the use of electric or magnetic elements directly sensitive to heat ; Power supply therefor, e.g. using thermoelectric elements using resistive elements the element being a linear resistance, e.g. platinum resistance thermometer in a specially-adapted circuit, e.g. bridge circuit in an oscillator circuit

Definitions

  • the invention relates to a device for determining and / or monitoring at least one process variable.
  • the process variable is, for example, moisture, temperature or flow of a medium, which is for example a liquid, a bulk material or a gas.
  • the invention relates to a method for determining and / or monitoring a frequency of a clock unit.
  • a variant is to perform the corresponding elements redundant and make occasional comparisons between the elements. However, this is costly and not easy to implement in terms of space requirements in the meter or sensor.
  • the invention has for its object to provide a cost-effective solution to the problem of unsafe components or elements.
  • the invention solves the problem on the one hand by a device for determining and / or monitoring a process variable and on the other by a method for determining and / or monitoring a frequency of a clock unit.
  • the invention solves the problem by a device for determining and / or monitoring at least one process variable, with at least a first measuring branch, which at least one electronic Reference element and / or an electronic measuring element having at least one second measuring branch, which has at least one electronic reference element and / or an electronic measuring element, and wherein at least one electronic element of the first measuring branch and at least one electronic element of the second measuring branch are interconnected such that there is a reference unit with at least one known parameter.
  • the device thus has at least two measuring branches which measure and / or monitor different or the same measuring or process variables.
  • the measuring branches have electronic components or elements which possibly serve for referencing within the respective measuring branch or the actual measurement.
  • At least two electronic elements of the two measuring branches are interconnected, so that there is a new reference unit with a new characteristic.
  • the reference elements are interconnected or, for example, the measuring elements, the latter combination then also having to take account of the respective measured quantities.
  • the characteristic of the measuring branches cross-reference unit then also refers, for example, the corresponding electronic properties.
  • the device is thus provided with at least one first measuring branch, which has at least one electronic reference element and with at least one second measuring branch, which has at least one electronic reference element, and wherein the reference element of the first measuring branch and the reference element of the second measuring branch are interconnected such that provides a reference unit with at least one known characteristic.
  • the device has thus, at least two measuring branches, which each have at least one reference element. With the two measuring branches, for example, the determination and / or monitoring of two process variables is possible or, for example, a measured variable can be measured redundantly.
  • the parameter of the switched reference unit preferably results from the characteristics of the individual reference elements. These are, for example, the parameters of components or units which describe their specific electrical properties.
  • the reference unit is designed in such a way that its parameter makes it possible to measure at least a part of the measuring device or a unit or a component of the measuring device. If, for example, a frequency or a clock rate is to be measured, then the parameter is, for example, a time constant.
  • the two measuring branches serve to determine and / or
  • At least two different process variables for example temperature, humidity, flow, level, pH, pressure, gas, etc.
  • at least one process variable is redundantly and / or additionally diversely measured by the two measuring branches, i. the measurements are identical or done in different ways.
  • the device according to the invention refers to any number, i. at least two measuring branches, so that any number of process or measured variables measured, or even redundant and / or diverse can be measured.
  • An embodiment of the device according to the invention includes that at least one clock unit is provided, which generates at least one frequency, and that the reference unit has at least one time constant.
  • the characteristic of the reference unit in this embodiment was therefore in particular a time constant.
  • This reference unit is characterized by a time constant.
  • the time constant is, for example, at least partially dependent on the dimensioning of the two reference elements.
  • the clock unit can then be checked by, for example, comparing the time constant determined by the reference unit via the clock unit with the suitably deposited value.
  • the time constant relates, for example, to an electronic behavior such as the charging or discharging behavior of the reference unit.
  • Time measurements are often realized via pulse counts.
  • the frequency f 0 provides the clock unit, so for example an oscillator.
  • the accuracy of the time measurement depends essentially on the errors of the oscillator frequency f 0 .
  • An embodiment of the device according to the invention provides that it is the clock unit to a microprocessor or a microcontroller or a resonant circuit.
  • An embodiment of the device according to the invention includes that the first measuring branch is used to measure a capacitive measuring transducer.
  • the capacitive measuring sensor is realized, for example, as a measuring capacitor whose capacitance depends on the process variable or on a change in the process variable, it is possible to deduce the process variable from the capacitance.
  • the measurements of the humidity or the level of a medium in a container are known. In both cases, the dielectric changes - in one case by the penetration of moisture, in the other case by the increase of the medium as a dielectric between two "capacitor plates" - and thus the capacity.
  • the first measuring branch comprises at least one RC element.
  • the capacitance can be determined, for example, with a known value of the electrical resistance, since the charging constant is equal to the product of the electrical resistance and the capacitance.
  • An embodiment of the device according to the invention includes that the second measuring branch is used to measure a measuring resistor.
  • a measuring resistor For example, resistance thermometers are known in which the electrical resistance is dependent on the temperature, so that the Measurement of the resistance value in a known dependence allows the determination or monitoring of the temperature.
  • the second measuring branch comprises at least one RC element.
  • the resistance of the temperature-dependent resistor can be determined via the charging curve of an RC element, insofar as, for example, a capacitor is specified as a known reference value.
  • An embodiment of the device according to the invention includes that the reference element of the first measuring branch is an electrical resistance, and that the reference element of the second measuring branch is an electrical capacitance.
  • the above embodiments for the measuring branches are thus summarized.
  • the measuring device is a measuring device for determining and / or monitoring two variables or, in particular, temperature and humidity.
  • both measuring branches monitor at least one identical process or measured variable.
  • An embodiment of the device according to the invention provides that the first measuring branch serves to measure the moisture, and that the second measuring branch is used to measure the temperature.
  • This refinement thus belongs to those in which the reference elements of the two measuring branches serve for the measurement of different process variables and in which the reference unit allows the measurement of a parameter which in turn is different therefrom.
  • An embodiment of the device according to the invention includes that the reference unit comprises at least one RC element.
  • the two reference elements allow the circuit of a complete RC element.
  • An embodiment of the device according to the invention provides that the clock unit at least the evaluation of the charging process and / or the discharging process of the first measuring branch and / or the second measuring branch is used.
  • a processor-internal RC oscillator as a clock unit is thus according to the invention a compensation of the temperature response of the clock unit by forming a reference time constant Rref * Cref performed as a reference unit.
  • Cx defines a size-dependent capacity, here for example for the measurement of moisture, and Rx a size-dependent, e.g. temperature-dependent resistance.
  • the value f (T) corresponds to the counting frequency at the unknown temperature T. With f o t o as a reference count for N 0 at the time t 0 , which is known and largely constant.
  • the accuracy of the drift compensation depends on the
  • a values of 50 ppm / K are acceptable for both Cref and Rref.
  • the invention solves the problem with a method for
  • a frequency of a clock unit wherein the clock unit is connected to at least one first measuring branch and a second measuring branch, each measuring branch having at least one reference element and / or at least one measuring element, wherein at least one element from the first measuring branch and at least one Element of the second measurement branch are interconnected such that there is a reference unit, which is characterized by at least one known time constant, wherein using the clock unit, a time constant of the reference unit is determined, and wherein the known time constant and the determined time constant are compared.
  • the method thus consists in that at least two electronic elements or components of two different measuring branches are connected to one another in such a way that a new reference unit results which has a size, via which the clock unit is then measured.
  • a new reference unit encompassing the measuring branches is generated by means of a combination of electronic components of these at least two measuring branches.
  • the method is part of a method for determining and / or monitoring at least one process variable, wherein the process variable is, for example, temperature, humidity, flow and / or the determination of a gas.
  • the frequency or clock rate of the clock unit is thereby used to increase or guarantee the accuracy of the measured values or to monitor the clock unit itself.
  • each measuring branch has at least one reference element, that at least the two reference elements of the two measuring branches are interconnected such that there is a reference unit, which is characterized by at least one known time constant.
  • a reference unit which has a time constant, which is predetermined and known by the properties of the reference elements. If this time constant is measured with the clock unit and a deviation from the previously known value results, then a deviation of the frequency of the clock unit from the frequency should be seen, over which the clock unit should actually have and with what value the evaluations and calculations are made ,
  • Fig. 1 a schematic representation of a measuring device
  • FIG. 2 shows a circuit of a sensor according to the invention.
  • Fig. 1 shows the basic structure of a sensor which serves both the measurement of moisture, as well as the measurement of the temperature.
  • two separate measuring branches 1, 2 are provided.
  • both measuring branches 1, 2 also use, for example, the same clock unit 5, so that both measuring branches 1, 2 can share the same elements otherwise.
  • both measuring branches are an RC element whose time constant is evaluated for the charging process or the discharging process.
  • the two measuring branches 1, 2 differ in that in the first measuring branch 1 the measuring capacitance 11 Cx is dependent on the humidity and that in the second measuring branch 2, the resistance value of the measuring resistor 12 Rx is dependent on the temperature.
  • a process variable can it may also be, for example, the detection or measurement of a gas.
  • the two measuring branches 1, 2 are controlled here by a microprocessor as a clock unit 5, which charges the two RC elements and, for example, evaluates the charging time. From the measured time, the time constant of the respective RC element, and thus the knowledge of the respective reference element, of the unknown variable of the temperature-dependent resistance or of the moisture-dependent capacity results.
  • the clock frequency of the microprocessor 5 may change due to aging or, for example, by the action of temperature or other process properties, whereby the measurement of the process variables or the evaluation of the measurement signals is uncertain or inaccurate.
  • the timing refers to the timing of the clock unit.
  • FIG. 2 shows how the two reference elements 3, 4 are connected to one another in such a way that a new reference unit 6 results.
  • the three switches 7 are provided. This results in a new RC element as a reference unit 6, the time constant resulting from the resistance of the reference resistor 3 and the capacitance of the reference capacitor 4.
  • the reference unit 6 thus results advantageously from the already existing components, so that there is a further measurement and thus a higher degree of accuracy without additional costs (except for the switch 7).
  • the reference unit 6 is appropriately controlled here.
  • the reference elements 3, 4 are preferably precision components. Another advantage is that for the Measurement of the two process variables temperature and humidity and for the monitoring of the clock unit 5 always the same measuring principle is applied.
  • the invention thus allows, for example, that clock units in general or especially microprocessors can be replaced or replaced more easily, since the clocking of the invention can be measured very accurately.
  • at least two clock units are provided. In the event that the frequency or clock rate of one of the two clock units falls below a certain value, it is switched to the other clock unit, so that it is active for the further measurements.
  • an alarm or error signal is generated and transferred, for example, to a higher-level unit.

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  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Investigating Or Analyzing Materials By The Use Of Electric Means (AREA)

Abstract

La présente invention concerne un dispositif de détermination et/ou de surveillance d'au moins une variable de processus, comportant au moins un bras de mesure (1) qui présente au moins un élément de référence électronique (3) et/ou un élément de mesure électronique (11) ; au moins un deuxième bras de mesure (2) qui présente au moins un élément de référence électronique (4) et/ou un élément de mesure électronique (12). Au moins un élément électronique (3, 11) du premier bras de mesure (1) et au moins un élément électronique (4, 12) du deuxième bras de mesure (2) pouvant être commutés conjointement, de sorte que l'on obtienne une unité de référence (6) comportant au moins une variable. En outre, l'invention concerne un procédé de détermination et/ou de surveillance d'une fréquence d'une unité d'horloge.
PCT/EP2008/058970 2007-09-07 2008-07-10 Dispositif de détermination et/ou de surveillance d'une variable d'un processus WO2009033845A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE102007042500.9A DE102007042500B4 (de) 2007-09-07 2007-09-07 Vorrichtung zur Bestimmung und/oder Überwachung einer Prozessgröße
DE102007042500.9 2007-09-07

Publications (1)

Publication Number Publication Date
WO2009033845A1 true WO2009033845A1 (fr) 2009-03-19

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PCT/EP2008/058970 WO2009033845A1 (fr) 2007-09-07 2008-07-10 Dispositif de détermination et/ou de surveillance d'une variable d'un processus

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DE (1) DE102007042500B4 (fr)
WO (1) WO2009033845A1 (fr)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN107167262A (zh) * 2017-06-19 2017-09-15 江苏师范大学 一种基于dsp的数字化温度检测电路

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US4431962A (en) * 1982-03-11 1984-02-14 Honeywell, Inc. Capacitor monitoring by single resistor adjustment
EP0106345A2 (fr) * 1982-10-18 1984-04-25 Honeywell Regelsysteme GmbH Circuit de linéarisation et de mesure pour un capteur capacitif
US4558595A (en) * 1985-03-29 1985-12-17 Honeywell Inc. Capacitance monitoring bridge circuit for an enthalpy responsive device
GB2206211A (en) * 1987-06-12 1988-12-29 Turnright Controls Sensor circuit
DE4312236A1 (de) * 1992-04-15 1993-10-21 Nat Semiconductor Corp Integrierte Schaltung für einen Mehrkomponentenkraftstoff-Sensor
EP0908736A2 (fr) * 1997-10-07 1999-04-14 i f m electronic gmbh Circuit pour déterminer la capacité ou la variation de capacité d'un circuit ou module capacitif
EP1411350A1 (fr) * 2002-10-18 2004-04-21 Siemens Building Technologies AG Sonde d'humidité avec un capteur capacitif d'humidité et méthode de mesure de l'humidité atmosphérique
US20050174129A1 (en) * 2004-02-06 2005-08-11 Dr. Johannes Heidenhain Gmbh Circuit arrangement for capacitive humidity measurement and method for operating the same
DE102005062005A1 (de) * 2005-12-22 2007-06-28 Innovative Sensor Technology Ist Ag Vorrichtung zur Bestimmung und/oder Überwachung mindestens einer Prozessgröße

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EP0318461A3 (fr) * 1982-08-12 1989-07-26 Omron Tateisi Electronics Co. Dispositif d'un montage de mesure
US4907449A (en) * 1986-10-31 1990-03-13 A.I.R., Inc. Meteorological data encoder for measuring atmospheric conditions
US4841458A (en) 1987-07-07 1989-06-20 Honeywell, Incorporated Analog to digital conversion by measuring the ratio of RC time constants
DE4202137C2 (de) * 1992-01-27 1994-02-24 Hygrometric Dr Brokmann Widerstands- und Kapazitätsmeßschaltung
TW418323B (en) * 1998-02-19 2001-01-11 Sumitomo Metal Ind Capacitance detection system and method
EP1637875A1 (fr) * 2004-09-17 2006-03-22 Fondazione Torino Wireless Capteur capacitif multifréquence et procédé de commande

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4431962A (en) * 1982-03-11 1984-02-14 Honeywell, Inc. Capacitor monitoring by single resistor adjustment
EP0106345A2 (fr) * 1982-10-18 1984-04-25 Honeywell Regelsysteme GmbH Circuit de linéarisation et de mesure pour un capteur capacitif
US4558595A (en) * 1985-03-29 1985-12-17 Honeywell Inc. Capacitance monitoring bridge circuit for an enthalpy responsive device
GB2206211A (en) * 1987-06-12 1988-12-29 Turnright Controls Sensor circuit
DE4312236A1 (de) * 1992-04-15 1993-10-21 Nat Semiconductor Corp Integrierte Schaltung für einen Mehrkomponentenkraftstoff-Sensor
EP0908736A2 (fr) * 1997-10-07 1999-04-14 i f m electronic gmbh Circuit pour déterminer la capacité ou la variation de capacité d'un circuit ou module capacitif
EP1411350A1 (fr) * 2002-10-18 2004-04-21 Siemens Building Technologies AG Sonde d'humidité avec un capteur capacitif d'humidité et méthode de mesure de l'humidité atmosphérique
US20050174129A1 (en) * 2004-02-06 2005-08-11 Dr. Johannes Heidenhain Gmbh Circuit arrangement for capacitive humidity measurement and method for operating the same
DE102005062005A1 (de) * 2005-12-22 2007-06-28 Innovative Sensor Technology Ist Ag Vorrichtung zur Bestimmung und/oder Überwachung mindestens einer Prozessgröße

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN107167262A (zh) * 2017-06-19 2017-09-15 江苏师范大学 一种基于dsp的数字化温度检测电路

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DE102007042500A1 (de) 2009-03-12
DE102007042500B4 (de) 2022-05-05

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