WO2013053905A2 - Capteur de pression et procédé permettant de vérifier le fonctionnement d'un capteur de pression - Google Patents

Capteur de pression et procédé permettant de vérifier le fonctionnement d'un capteur de pression Download PDF

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Publication number
WO2013053905A2
WO2013053905A2 PCT/EP2012/070295 EP2012070295W WO2013053905A2 WO 2013053905 A2 WO2013053905 A2 WO 2013053905A2 EP 2012070295 W EP2012070295 W EP 2012070295W WO 2013053905 A2 WO2013053905 A2 WO 2013053905A2
Authority
WO
WIPO (PCT)
Prior art keywords
temperature
pressure
diode
voltage
zener
Prior art date
Application number
PCT/EP2012/070295
Other languages
German (de)
English (en)
Other versions
WO2013053905A3 (fr
Inventor
Markus Messmer
Rolf Mueller
Heinz Walter
Original Assignee
Ifm Electronic Gmbh
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 Ifm Electronic Gmbh filed Critical Ifm Electronic Gmbh
Priority to DE112012002911.9T priority Critical patent/DE112012002911B4/de
Publication of WO2013053905A2 publication Critical patent/WO2013053905A2/fr
Publication of WO2013053905A3 publication Critical patent/WO2013053905A3/fr

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Classifications

    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01L—MEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE
    • G01L19/00—Details of, or accessories for, apparatus for measuring steady or quasi-steady pressure of a fluent medium insofar as such details or accessories are not special to particular types of pressure gauges
    • G01L19/0092—Pressure sensor associated with other sensors, e.g. for measuring acceleration or temperature
    • 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
    • G01K15/007—Testing
    • 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
    • G01K7/01—Measuring temperature based on the use of electric or magnetic elements directly sensitive to heat ; Power supply therefor, e.g. using thermoelectric elements using semiconducting elements having PN junctions
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01L—MEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE
    • G01L27/00—Testing or calibrating of apparatus for measuring fluid pressure
    • G01L27/007—Malfunction diagnosis, i.e. diagnosing a sensor defect

Definitions

  • the invention relates to a pressure sensor for detecting the pressure prevailing in a medium, wherein the pressure sensor comprises a pressure measuring cell with at least one transducer and a temperature sensor designed as a diode, in particular as a Zener diode for detecting the temperature prevailing at the pressure measuring cell, and a method for Checking the function of a pressure sensor.
  • Pressure sensors are used in many industries for pressure measurement, with the capacitive pressure sensor being a typical design. capacitive
  • Pressure sensors often have a ceramic pressure measuring cell, as a transducer for the process pressure, and an evaluation for signal processing.
  • the pressure within a medium adjacent to a measuring cell is often to be detected.
  • the measuring cell is part of the
  • Measuring device typically consists of a ceramic body and a membrane, wherein between the base body and the membrane, a glass solder ring is arranged.
  • the resulting cavity between the body and membrane allows the longitudinal mobility of the membrane due to a pressure influence.
  • On the underside of the membrane and on the opposite upper side of the main body electrodes are provided, which together form a measuring capacitor.
  • Measuring cells and measuring devices of this type have been known for a long time and are used, for example, in many areas of process measuring technology for metrological process monitoring. Such measuring devices are manufactured by the applicant, for example, under the device names PNxx and Plxx and placed on the market. The measuring ranges are currently usually up to 600 bar.
  • the temperature infiuence on the measurement result plays a major role.
  • the evaluated in the pressure measurement Capacity change is also dependent on the permittivity of the medium, which is located within the ceramic body and thus between the electrodes.
  • this medium is air.
  • this permittivity may change, whereby a pressure change is detected, the actual amount may differ from the measured value.
  • the actual pressure change may be zero while the meter is reading
  • the transducer must be temperature compensated, i. the proportion of the temperature prevailing in the immediate vicinity of the converter must be taken out of the measured capacitance value or voltage or current value, so that all measured values without temperature influence are comparable with each other.
  • a temperature sensor can be provided on the measuring cell.
  • a temperature sensor is usually an NTC or PTC temperature probe in question, for example, as a Pt100 resistance thermometer
  • an evaluation unit e.g. one
  • Microcontroller then can mathematically the measured pressure value to the
  • Degradation effects are subject, which can lead to a false measurement of the temperature and thus to an incorrect compensation of the measured pressure value.
  • a reliable temperature measurement is necessary. Especially at
  • Temperature detection or errors in the temperature detection must be detected safely.
  • a common method for permanently checking the temperature sensor is a redundant design.
  • the measured values of at least two temperature sensors are compared in terms of magnitude and a malfunction is detected with a correspondingly large deviation.
  • a disadvantage of this simple redundant design is In addition to the temperature gradient between the two components that systematic errors are difficult or impossible to detect. In addition, drift and aging effects are subject to a certain degree of randomness, so that it can not be ruled out that both temperature sensors have the same or similar error behavior over time. The magnitude comparison of both temperature readings would not reveal any irregularities in this case.
  • DE 10 2004 035 014 A1 proposes a construction with diverse redundancy.
  • This arrangement includes at least two sensor elements with temperature-dependent impedance, which are integrated thermally coupled within a sensor head.
  • the temperature-dependent impedances have different temperature / resistance characteristics, so the diversified
  • the object of the invention is to further improve the reliable temperature measurement while taking up space and in particular the manufacturing costs
  • the indicated object is achieved by a method with the features of claim 1, a method having the features of claim 2 and a pressure sensor with the features of claim 7.
  • the pressure sensor has a pressure measuring cell with at least one measuring transducer and a temperature measuring transducer designed as a diode, in particular a Zener diode, for detecting the temperature prevailing at the pressure measuring cell.
  • the diode is now operated alternately in the forward direction and in the reverse direction and thereby becomes a temperature-dependent
  • the adjustment procedure essentially involves the storage of the
  • Temperature characteristic of both the passing and the Zener voltage i. the behavior of the voltage over a temperature range which is typically between -40 ° C and + 125 ° C. With these stored characteristics, it is then possible to determine the associated temperature for each measured continuity and Zener voltage.
  • the zener diode thus works or acts as two redundant, diverse temperature sensors, since two components of this one component
  • Temperature information can be obtained.
  • the advantage of this is that with a Zener diode, these two properties are combined in a semiconductor crystal and thus a temperature gradient is negligible.
  • Zener diode instead of a Zener diode also a circuit network - eg transistor with resistors - used which is then used as a bipolar. The alternative may be necessary for a more accurate temperature measurement or for a larger temperature range.
  • a pressure value p1 which is compensated with the temperature determined by the forward voltage, from the pressure value measured by the pressure measuring cell, and from the pressure value measured by the pressure measuring cell to form a pressure value p2, which is compensated with the temperature determined by the Zener voltage.
  • Pressure values are compared. This has the advantage that there is already a further processable signal, if the comparison does not give any irregularities, and any irregularities during the temperature compensation can be monitored with.
  • the lookup table is stored in a microcontroller, for example in an EEPROM.
  • the microcontroller has two ports, one acting as an input and the other as an output.
  • the microcontroller has three ports, two acting as an output and one as an input.
  • One of the outputs works advantageously as an inverter. In this way, it is possible to take advantage of the available voltage range of typically 0V to 5V to a greater extent. Thus Zener diodes with a higher zener voltage than the temperature measuring element are also possible.
  • the object is further achieved by a pressure sensor in which
  • the temperature detection diode is connected to a microcontroller, the diode via its I / O port with a
  • FIG. 1 shows a first embodiment of a pressure measuring cell with a Zener diode as
  • Figure 2 shows a second embodiment of a pressure measuring cell with a Zener diode as
  • FIG. 3 shows a measuring circuit for reliable temperature detection
  • Figure 4 shows the voltage waveforms at I / O pin and A / D input pin of
  • Figure 5 shows a measuring circuit with two voltage sources
  • FIG. 6 shows a measuring circuit with a voltage source.
  • FIG. 1 shows a first embodiment of a pressure measuring cell 1 with a Zener diode D1 as a temperature sensor.
  • the pressure measuring cell 1 consists of a ceramic base body 4 with a membrane against which the pressure to be measured is applied. Such measuring cells are well known and require no further description at this point.
  • On the upper side of the ceramic base body 4 is spaced apart a component carrier 3 for receiving the evaluation of the capacity change necessary electronic circuit 2.
  • the component carrier 3 is designed as a board or also made of ceramic. The spacing is effected by the Kunststoffuspins, through which the evaluation circuit 2 with the
  • Capacitance change measuring electrodes is connected.
  • the pressure measuring cell 1 is influenced by the surrounding temperature. Even if the temperature in Fig. 1 is indicated only by the arrow from below, so nevertheless completely surrounds the measuring cell 1. But since a change in temperature predominantly emanates from the medium to be measured, the arrow was drawn on the underside. Ultimately, a temperature change affects that
  • Temperature sensor as close as possible to the measuring cell.
  • the temperature sensor is designed as a Zener diode D1 and is located on the underside of the component carrier. 3
  • FIG. 2 shows a second embodiment of a pressure measuring cell 1 with a Zener diode D1 as a temperature sensor. Instead, the entire evaluation circuit 2 together with the Zener diode D1 is located on the upper side of the ceramic base body 4. Otherwise, the measuring cell 1 is comparable to the measuring cell known from FIG.
  • FIG. 3 shows a schematic diagram of how a measuring circuit for
  • Microcontroller 10 is a square wave signal.
  • the resistor R1 serves as
  • the resistors R2 and R3 form a voltage divider for influencing the
  • R3 can also be designed as a voltage reference in the form of a diode.
  • the second, denoted by ADC port of the microcontroller 10 is an input at which received by the Zener diode D1 square wave signal is received, digitized and forwarded for further processing.
  • the appearance of the signals on the two ports is illustrated in the following FIG. 4.
  • the signal curve marked “A” in FIG. 4 depicts the rectangular signal generated by the microcontroller 10 and applied to the I / O port, while the lower diagram, labeled "B", represents the modified signal at the ADC input of the MicroController 10 represents.
  • VSS is at 0V and VCC at 5V.
  • the generated square wave alternates from OV to 5V.
  • the Zener diode D1 the signal is changed so that it only between the zener voltage U z and the
  • FIG. 5 shows a first exemplary embodiment for implementing the method according to the invention.
  • the two resistors R2 and R3 were replaced by two voltage sources of 2.5V each to avoid the losses occurring at the resistors.
  • the microcontroller 10 is operated at 5V, while the Zener diode D1 is at a potential of 2.5V. Accordingly, the Zener diode D1 can be dimensioned to about 2.4V.
  • the resistor R1 is as explained above a series resistor for limiting the current flowing through the Zener diode D1 current.
  • At the I / O port is a rectangular signal of 0-5V, which is alternately received at the ADC port of the microcontroller 10 according to the diagram in Fig.
  • Uz is equal to "1" and UF is "0". If the path for Uz is switched through, the amount for Uz is determined and compared with the stored temperature characteristic curve 12b.
  • This characteristic curve 12b was stored in a memory 11, for example an EEPROM, at the factory and represents the voltage curve of Uz over the temperature. UF is processed in the same way. If the path for UF is switched through, the amount for UF is determined and compared with the stored for U F temperature characteristic 12a, which is also stored in the memory 1 1.
  • Uz and UF are temperature-dependent, so that after the adjustment with the characteristic curves 12a, 12b the respectively measured temperature can be determined.
  • a memory 1 1 downstream comparator unit 13 the two determined temperature amounts are compared. If - in the frame an agreed tolerance - it is determined that the amounts are the same, this is an indication that the Z-diode D1 works correctly and that the determined amount can be further processed for temperature compensation.
  • Temperature measurement is not done correctly, which can be pointed out accordingly by a signal output, not shown, an optical and / or audible warning.
  • both characteristic curves 12a, 12b shown in FIG. 5 can each already output the pressure values corrected by the measured temperature, which are then compared in the comparator unit 13 in order to obtain information about the reliability of the temperature measurement.
  • the advantage here is that in the event that the difference between the two compared pressure values is zero, this pressure value can be passed on directly for further processing.
  • FIG. 6 shows a second exemplary embodiment for implementing the
  • the Zener diode D1 is applied in Fig. 6 with 5V. This increases the choice of Zener diodes since the Zener voltage can be in the range of 2V to 4.7V. Depending on how accurate the temperature measurement should be, Z-diodes with 1 mV / K or 2-3mV / K can be used, just to name two examples. The advantage of Zener diodes with greater Zener voltage is that the evaluable range increases and thus the characteristic curve is more accurate. The subsequent A / D conversion may then be at a lower resolution
  • the larger voltage range is achieved by the microcontroller 10 having a further output which outputs the rectangular signal applied exactly inverted at the first output. In this way, the edge height of the rectangular signal doubles. It can be dispensed with the second voltage source, so that only a voltage source with 5V is necessary. Receiving and Further processing of the signal is otherwise in the same way as in

Abstract

L'invention concerne un procédé permettant de vérifier le fonctionnement d'un capteur de pression servant à détecter la pression présente dans un fluide, le capteur de pression comportant une cellule manométrique munie d'au moins un transducteur de mesure et d'un dispositif de détection de mesure de température réalisé sous la forme d'une diode Zener pour la détection de la température présente au niveau de la cellule manométrique. L'invention concerne également ledit capteur de pression. Selon l'invention, la diode fonctionne alternativement dans le sens passant et dans le sens bloquant, et on mesure alors respectivement une tension de passage fonction de la température et une tension Zener fonction de la température. Les deux courbes caractéristiques de la tension de passage et de la tension Zener ont auparavant été mémorisées dans une procédure d'ajustement en termes de température dans une table de recherche. A chacune des deux valeurs mesurées de la tension de passage et de la tension Zener est respectivement associée la température qui lui correspond dans la table de recherche, et on détermine la différence entre les deux valeurs de température. Un dépassement significatif au-dessus ou en dessous de la valeur zéro permet d'identifier un fonctionnement défectueux du dispositif de détection de mesure de température.
PCT/EP2012/070295 2011-10-14 2012-10-12 Capteur de pression et procédé permettant de vérifier le fonctionnement d'un capteur de pression WO2013053905A2 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
DE112012002911.9T DE112012002911B4 (de) 2011-10-14 2012-10-12 Drucksensor und Verfahren zur Überprüfung der Funktion eines Drucksensors

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE102011084514A DE102011084514A1 (de) 2011-10-14 2011-10-14 Verfahren zur Überprüfung der Funktion eines Drucksensors
DE102011084514.3 2011-10-14

Publications (2)

Publication Number Publication Date
WO2013053905A2 true WO2013053905A2 (fr) 2013-04-18
WO2013053905A3 WO2013053905A3 (fr) 2014-03-20

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WO (1) WO2013053905A2 (fr)

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE102015222756A1 (de) 2015-11-18 2017-05-18 Robert Bosch Gmbh Sensorelement für einen Drucksensor

Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE102004035014A1 (de) 2004-07-20 2006-02-16 Joachim Krieger Anordnung von Sensorelementen zum zuverlässigen Messen einer Temperatur

Family Cites Families (6)

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Publication number Priority date Publication date Assignee Title
US3250991A (en) * 1962-06-29 1966-05-10 Frontier Dev Inc Temperature measuring bridge circuit having a pair of zener diodes as part of the bridge circuit
US3413853A (en) * 1966-04-11 1968-12-03 Gen Electric Zener diode temperature meter
US4126826A (en) * 1977-09-19 1978-11-21 National Semiconductor Corporation Measurement system signal isolation
GB2263975B (en) * 1992-01-22 1995-01-25 Rover Group A method of detecting malfunction in a piezoelectric sensor system
US5329818A (en) * 1992-05-28 1994-07-19 Rosemount Inc. Correction of a pressure indication in a pressure transducer due to variations of an environmental condition
DE102008020862B3 (de) * 2008-04-25 2009-05-14 Siemens Aktiengesellschaft Messumformer zur Prozessinstrumentierung und Verfahren zur Überwachung des Zustands dessen Sensors

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE102004035014A1 (de) 2004-07-20 2006-02-16 Joachim Krieger Anordnung von Sensorelementen zum zuverlässigen Messen einer Temperatur

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DE102011084514A1 (de) 2013-04-18
WO2013053905A3 (fr) 2014-03-20
DE112012002911A5 (de) 2014-03-20
DE112012002911B4 (de) 2016-03-31

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