GB2183342A - Displaying corrected transducer readings - Google Patents

Displaying corrected transducer readings Download PDF

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Publication number
GB2183342A
GB2183342A GB08526275A GB8526275A GB2183342A GB 2183342 A GB2183342 A GB 2183342A GB 08526275 A GB08526275 A GB 08526275A GB 8526275 A GB8526275 A GB 8526275A GB 2183342 A GB2183342 A GB 2183342A
Authority
GB
United Kingdom
Prior art keywords
transducer
eprom
thermocouple
corrected
digital
Prior art date
Legal status (The legal status 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 status listed.)
Withdrawn
Application number
GB08526275A
Other versions
GB8526275D0 (en
Inventor
Robin Andras Benedek
Steven Burt
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Johnson Matthey PLC
Original Assignee
Johnson Matthey PLC
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 Johnson Matthey PLC filed Critical Johnson Matthey PLC
Priority to GB08526275A priority Critical patent/GB2183342A/en
Publication of GB8526275D0 publication Critical patent/GB8526275D0/en
Publication of GB2183342A publication Critical patent/GB2183342A/en
Withdrawn legal-status Critical Current

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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
    • G01D3/00—Indicating or recording apparatus with provision for the special purposes referred to in the subgroups
    • G01D3/02—Indicating or recording apparatus with provision for the special purposes referred to in the subgroups with provision for altering or correcting the law of variation
    • G01D3/022—Indicating or recording apparatus with provision for the special purposes referred to in the subgroups with provision for altering or correcting the law of variation having an ideal characteristic, map or correction data stored in a digital memory
    • 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
    • G01D3/00—Indicating or recording apparatus with provision for the special purposes referred to in the subgroups
    • G01D3/028—Indicating or recording apparatus with provision for the special purposes referred to in the subgroups mitigating undesired influences, e.g. temperature, pressure
    • G01D3/032—Indicating or recording apparatus with provision for the special purposes referred to in the subgroups mitigating undesired influences, e.g. temperature, pressure affecting incoming signal, e.g. by averaging; gating undesired signals
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01K—MEASURING TEMPERATURE; MEASURING QUANTITY OF HEAT; THERMALLY-SENSITIVE ELEMENTS NOT OTHERWISE PROVIDED FOR
    • G01K1/00—Details of thermometers not specially adapted for particular types of thermometer
    • G01K1/02—Means for indicating or recording specially adapted for 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
    • G01K7/02—Measuring temperature based on the use of electric or magnetic elements directly sensitive to heat ; Power supply therefor, e.g. using thermoelectric elements using thermoelectric elements, e.g. thermocouples
    • G01K7/021—Particular circuit arrangements

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  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • Technology Law (AREA)
  • Indication And Recording Devices For Special Purposes And Tariff Metering Devices (AREA)
  • Measuring Temperature Or Quantity Of Heat (AREA)

Abstract

The present invention provides apparatus for displaying corrected readings of a transducer, such as a thermocouple. Previously proposed temperature measuring apparatus incorporating a thermocouple have required regular recalibration if accuracy is to be maintained. The present invention is directed to at least reducing such a requirement and there is provided an apparatus for displaying a corrected transducer reading comprises separate transducer 3 and display unit 2 connected by a multi-way plug fitting. One part of the multi-way plug fitting has contacts connected to the transducer 3 and also contacts connected to the terminals of an EPROM 4 which forms part of the transducer unit, and is preferably contained within the plug fitting, which is electrically shielded. The display unit contains an A/D convertor 6 and microprocessor 7 which obtains from the EPROM the data necessary to give a corrected digital value for the transducer reading. This may be displayed in digital form, or stored in a buffer 10 to be used by a computer or a control system, or it may be converted back to analog form where an analog input is required or other display or control equipment. <IMAGE>

Description

SPECIFICATION Apparatus for displaying corrected transducer readings.
The present invention providesapparatusfor displaying corrected readings of a transducer, such as a thermocouple.
Thermocouples used for accurate temperature measurements need to be individually calibrated; furthermore, after a period of use they require to be recalibrated if accuracy is to be maintained. In the past the calibration of a thermocouple has generally been expressed in a calibration curve giving the correction which must be applied to each thermocouple reading to bring itto a nominal corrected value. Not only is this process time consuming and inconvenient, but it may also be a sourceoferrorwherea numberofthermocouples are in use, since the wrong calibration curvefora particular thermocouple may be selected by mistake.
It has also been proposed to incorporate in a display instrumentforathermocouple an electrically programmable read only memory (EPROM) programmed with the data enabling linearised thermocouple readings to be computed for each particulartype of thermocouple. The EPROM in this arrangement takes no account of calibration errors, which must be allowed for separately.
The present invention is directed to overcoming these difficulties. In the invention which is defined in the claims appended hereto, apparatusfor displaying a corrected transducer reading comprises separate transducer and display units connected by a multi-way plug fitting. One part of the multi-way plug fitting has contacts connected to the transducer, and also contacts connected totheterminals of an EPROM which forms part ofthe transducer unit, and is preferably contained within the plug fitting, which is electrically shielded. The display unit contains a digital-to-analog convertor which converts the output of the transducer, amplified as necessary, into digital form to be applied to a microprocessor.
The microprocessorthen obtainsfrom the EPROM the data necessary to give a corrected digital value forthetransducer reading. This may be displayed in digital form, orstored in a bufferto be used bya computer or a control system, or it may be converted backto analog form where an analog input is required for other display or control equipment.
The invention will be described with reference, particularly, to thermocouples forfurnace temperature control, but it is applicableto any other form oftransducerwhose readings may require correction, or which may need to be recalibrated from time to time.
In the application of the invention to thermocouples, when athermocouple needs to be recalibrated the unit is sent away as a whole, the thermocouple is recalibrated and the EPROM reprogrammed to take account of any change in calibration that may have occurred.
Sincethethermocoupleand its correction contained in the EPROM are in a single plug-in unit it is impossible to use one thermocouple with a calibration intended for another.
The invention will be further described by way of example with reference to the accompanying drawing, which is a block schematic diagram of one embodiment.
Referring to this drawing, the apparatus, which is designed for the accurate measurement offurnace temperature by means of a thermocouple, comprises two units, 1 and 2, interconnected by means of a multi-way plug and socketconnector(not shown in thefigure). Thefirst ofthese units lisa transducer unit comprising a thermocouple 3 and an EPROM 4. The EPROM is contained withinthe multi-way plug body, which is electrostatically shielded. This shielding is necessary because, in general, the apparatus is likely to be used in proximityto furnace controllers and process timers and other switching devices liable to generate electrical interference in the form of voltage spikes.It is therefore desirablethatthe EPROM should beas close as possible to the digital processing circuits about to be described, and should be adequately shielded.
The second unit 2 of the apparatus is the display unit. This contains an amplifier having its input connected through the multi-way plug to the thermocouple 3, an analog-to-digital convertor 6, receiving its inputfrom the amplifier and providing digital output to a microprocessor7, and a digital display 8. The microprocessor7 is coupled bya multi-channel two-way bus 9through the pins ofthe multi-way connectorto the EPROM 4.
Initially, and from time to time during service, the transducer unit 1 is unplugged and the thermocouple calibrated. Data necessary to convert the actual thermocouple readings to ideal thermocouple readings are then programmed into the EPROM. These may comprise a look-up table or the coefficients of a mathematical function defining a correction curve. The table orfunction may provide corrected values directly, or may provide a correction term to be added to or subtracted from the digitisedthermocouple reading.
In operation,the microprocessorcontainsaclock which at frequent intervals generates an interrupt. At each interruptthe digitized value of the thermocouple voltage is read in from the analog-to-digital convertor 6. The microprocessor then addressessthe EPROM and computes the correction to be applied to this valueto convert itto idealised thermocouple readings, and the digital reading then either displayed as a voltage, or is converted to equivalent temperature and is displayed on the display 8. The digital reading may also be sent to a buffer memory 10from which it can betransmitted to a computerforfurther processing, orto a recorder or a furnace controller.
Optionally, also, the digital value may be sent to a digital-to-analog convertor 11 to provide an analog output signal where such a signal is required for a temperature recorder orfurnace controller.
It will be noted that at each recalibration the data in the EPROM are altered to compensate for any change in thethermocouple characteristic, sothata thermocouple may be kept in use even after it has departed appreciablyfrom itstheoreticallyideal characteristic. Furthermore, thermocouples may be interchanged withoutfear of introducing substantial errors, and may even be replaced by thermocouples using other metals and having differenttemperature voltage characteristic curves, provided that the EPROM of each is loaded with the appropriate compensating function or look-up table.
Although the above description has related to thermocouples,itisapparentthatasimilar technique could be used with other types of transducer, for example, vacuum gauges used in connection with vacuum evaporation and sputtering processes, and gas analysers.

Claims (4)

1. Apparatus for displaying a corrected transducer reading comprising a transducer and a displayunit,theapparatus including anEPROM storing data for correcting the transducer output, characterised in that thetransducer (3) and EPROM (4) are combined into a single unit (1), each being connected to contacts of one portion of a multi-way plugfitting,andthedisplayunit(2) is connected to the other portion ofthe multi-way plug fitting and includes an analog-to-digital convertor (6) and a digital data processor arranged to receive, from the anaiog-to-digital convertor (6),the digitised value of the output ofthe transducer (3), and to address the EPROM (4) to obtain correction data and to compute a corrected value for the transducer output.
2. Apparatus according to the Claim 1 in which the transducer is a thermocouple.
3. ApparatusaccordingtoClaiml orClaim2in which the EPROM is contained within the multi-way plugportionofthetransducerunitand issurrounded by electrostatic screening.
4. Apparatus according to any preceding claim in which the output of the microprocessor is supplied to a digital-to-analog conventorto give an analog output.
GB08526275A 1985-10-24 1985-10-24 Displaying corrected transducer readings Withdrawn GB2183342A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
GB08526275A GB2183342A (en) 1985-10-24 1985-10-24 Displaying corrected transducer readings

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB08526275A GB2183342A (en) 1985-10-24 1985-10-24 Displaying corrected transducer readings

Publications (2)

Publication Number Publication Date
GB8526275D0 GB8526275D0 (en) 1985-11-27
GB2183342A true GB2183342A (en) 1987-06-03

Family

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Family Applications (1)

Application Number Title Priority Date Filing Date
GB08526275A Withdrawn GB2183342A (en) 1985-10-24 1985-10-24 Displaying corrected transducer readings

Country Status (1)

Country Link
GB (1) GB2183342A (en)

Cited By (19)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3905664A1 (en) * 1989-02-24 1990-08-30 Vdo Schindling Circuit arrangement with a sensor
WO1992003705A1 (en) * 1990-08-20 1992-03-05 Rosemount Limited A transmitter
DE4139122C1 (en) * 1991-11-28 1993-04-08 Fenzlein, Paul-Gerhard, 8500 Nuernberg, De
EP0540407A2 (en) * 1991-10-30 1993-05-05 Société anonyme dite: LABINAL Device for measuring parameters, in particular parameters relating to the wheels of aeroplanes or vehicles
WO1993009415A1 (en) * 1991-10-31 1993-05-13 Testel S.P.A. A device for temperature measurement and control
DE4204429A1 (en) * 1992-02-14 1993-08-26 Marina Frank Programmable system for measuring physical parameters - has programming- and reading-unit and small measurement device contg. sensor unit and clock
DE4320861A1 (en) * 1993-06-23 1995-01-05 Hekatron Gmbh Circuit arrangement for an optical detector for environmental monitoring and display of an interference medium
EP0671036A1 (en) * 1992-11-25 1995-09-13 McBean, Ronald V. Instrumentation system with multiple sensor modules
NL9600011A (en) * 1981-11-10 1996-08-01 Cordis Europ Sensor system
FR2737777A1 (en) * 1995-08-11 1997-02-14 Motorola Semiconducteurs SENSOR MODULE
DE19702878A1 (en) * 1997-01-28 1998-07-30 Stepper & Co Decentralised measurement device
DE29714517U1 (en) * 1997-08-13 1998-09-10 Siemens Ag Transmitter
EP0950875A1 (en) * 1998-04-14 1999-10-20 Elektro-Mechanik Gmbh Device for measuring mechanical movements
DE10064859A1 (en) * 2000-12-23 2002-07-04 Maz Mikroelektronik Anwendungs Self-calibrating measurement sensor has auxiliary sensor, forming part of the same integrated circuit, for use in determining characteristic curve, offset and non-linearities with increased production yield for the same accuracy
WO2003002966A1 (en) * 2001-06-27 2003-01-09 Sherwood Services Ag Temperature probe adapter
WO2005061995A1 (en) * 2003-12-11 2005-07-07 Sartorius Ag Measuring device
US6921198B2 (en) * 2003-06-12 2005-07-26 Medivance Incorporated Patient temperature repeating system and method
EP1793215A1 (en) * 2005-11-30 2007-06-06 Deutsches Zentrum für Luft- und Raumfahrt e.V. Method and device for determining a temperature by means of a thermocouple
WO2009042033A2 (en) * 2007-09-21 2009-04-02 Siemens Energy & Automation, Inc. Managing a thermocouple module

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2008773A (en) * 1977-09-05 1979-06-06 Grandison Trading Co Ltd Weighing Apparatus
GB2065890A (en) * 1979-12-14 1981-07-01 Honeywell Inc Sensor system with non-linearity correction
GB2097536A (en) * 1981-04-24 1982-11-03 Wolfendale Peter Caleb Frederi Correcting transducer measurements
EP0079086A1 (en) * 1981-11-10 1983-05-18 Sentron v.o.f. Catheter sensor and memory unit
GB2144225A (en) * 1983-07-27 1985-02-27 Sundstrand Data Control Transducer memory circuit

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2008773A (en) * 1977-09-05 1979-06-06 Grandison Trading Co Ltd Weighing Apparatus
GB2065890A (en) * 1979-12-14 1981-07-01 Honeywell Inc Sensor system with non-linearity correction
GB2097536A (en) * 1981-04-24 1982-11-03 Wolfendale Peter Caleb Frederi Correcting transducer measurements
EP0079086A1 (en) * 1981-11-10 1983-05-18 Sentron v.o.f. Catheter sensor and memory unit
GB2144225A (en) * 1983-07-27 1985-02-27 Sundstrand Data Control Transducer memory circuit

Cited By (31)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
NL9600011A (en) * 1981-11-10 1996-08-01 Cordis Europ Sensor system
DE3905664A1 (en) * 1989-02-24 1990-08-30 Vdo Schindling Circuit arrangement with a sensor
WO1992003705A1 (en) * 1990-08-20 1992-03-05 Rosemount Limited A transmitter
US5451939A (en) * 1990-08-20 1995-09-19 Fisher-Rosemount Limited Microprocessor controlled transmitter for connection to a sensor and a method of transferring digital signals to the microprocessor
US5521846A (en) * 1991-10-30 1996-05-28 Labinal, Societe Anonyme Device for measuring parameters, in particular parameters relating to aircraft or vehicle wheels
EP0540407A2 (en) * 1991-10-30 1993-05-05 Société anonyme dite: LABINAL Device for measuring parameters, in particular parameters relating to the wheels of aeroplanes or vehicles
FR2683313A1 (en) * 1991-10-30 1993-05-07 Labinal DEVICE FOR MEASURING PARAMETERS, IN PARTICULAR PARAMETERS RELATING TO AIRCRAFT WHEELS OR VEHICLES.
EP0540407A3 (en) * 1991-10-30 1994-03-02 Labinal Sa
WO1993009415A1 (en) * 1991-10-31 1993-05-13 Testel S.P.A. A device for temperature measurement and control
DE4139122C1 (en) * 1991-11-28 1993-04-08 Fenzlein, Paul-Gerhard, 8500 Nuernberg, De
US5425361A (en) * 1991-11-28 1995-06-20 Paul-Gerhard Fenzlein Apparatus for the determination of medical, electro-chemical measured values relevant to organic or metabolic functions
DE4204429A1 (en) * 1992-02-14 1993-08-26 Marina Frank Programmable system for measuring physical parameters - has programming- and reading-unit and small measurement device contg. sensor unit and clock
EP0671036A4 (en) * 1992-11-25 1996-08-21 Ronald V Mcbean Instrumentation system with multiple sensor modules.
EP0671036A1 (en) * 1992-11-25 1995-09-13 McBean, Ronald V. Instrumentation system with multiple sensor modules
DE4320861A1 (en) * 1993-06-23 1995-01-05 Hekatron Gmbh Circuit arrangement for an optical detector for environmental monitoring and display of an interference medium
FR2737777A1 (en) * 1995-08-11 1997-02-14 Motorola Semiconducteurs SENSOR MODULE
EP0758739A1 (en) * 1995-08-11 1997-02-19 Motorola Semiconducteurs S.A. Sensor module
DE19702878A1 (en) * 1997-01-28 1998-07-30 Stepper & Co Decentralised measurement device
DE29714517U1 (en) * 1997-08-13 1998-09-10 Siemens Ag Transmitter
EP0950875A1 (en) * 1998-04-14 1999-10-20 Elektro-Mechanik Gmbh Device for measuring mechanical movements
DE10064859A1 (en) * 2000-12-23 2002-07-04 Maz Mikroelektronik Anwendungs Self-calibrating measurement sensor has auxiliary sensor, forming part of the same integrated circuit, for use in determining characteristic curve, offset and non-linearities with increased production yield for the same accuracy
WO2003002966A1 (en) * 2001-06-27 2003-01-09 Sherwood Services Ag Temperature probe adapter
KR100782678B1 (en) 2001-06-27 2007-12-07 코비디엔 아게 Temperature probe adapter
US6921198B2 (en) * 2003-06-12 2005-07-26 Medivance Incorporated Patient temperature repeating system and method
WO2005061995A1 (en) * 2003-12-11 2005-07-07 Sartorius Ag Measuring device
US7623980B2 (en) 2003-12-11 2009-11-24 Sartorius Measuring device with evaluation unit and external memory
EP1793215A1 (en) * 2005-11-30 2007-06-06 Deutsches Zentrum für Luft- und Raumfahrt e.V. Method and device for determining a temperature by means of a thermocouple
WO2009042033A2 (en) * 2007-09-21 2009-04-02 Siemens Energy & Automation, Inc. Managing a thermocouple module
WO2009042033A3 (en) * 2007-09-21 2009-05-14 Siemens Energy & Automat Managing a thermocouple module
US8702306B2 (en) 2007-09-21 2014-04-22 Siemens Industry, Inc. Systems, devices, and/or methods for managing a thermocouple module
US9995640B2 (en) 2007-09-21 2018-06-12 Siemens Industry, Inc. Systems, devices, and/or methods for managing a thermocouple module

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Publication number Publication date
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WAP Application withdrawn, taken to be withdrawn or refused ** after publication under section 16(1)