EP0593701A1 - Appareil de mesure des champs magnetiques - Google Patents

Appareil de mesure des champs magnetiques

Info

Publication number
EP0593701A1
EP0593701A1 EP93907742A EP93907742A EP0593701A1 EP 0593701 A1 EP0593701 A1 EP 0593701A1 EP 93907742 A EP93907742 A EP 93907742A EP 93907742 A EP93907742 A EP 93907742A EP 0593701 A1 EP0593701 A1 EP 0593701A1
Authority
EP
European Patent Office
Prior art keywords
value
magnetic field
polarity
measuring
probe
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Withdrawn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
EP93907742A
Other languages
German (de)
English (en)
Inventor
Albert Maurer
Urs Meyer
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.)
MAURER, ALBERT
Original Assignee
Maurer Magnetic 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 Maurer Magnetic AG filed Critical Maurer Magnetic AG
Publication of EP0593701A1 publication Critical patent/EP0593701A1/fr
Withdrawn legal-status Critical Current

Links

Classifications

    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R33/00—Arrangements or instruments for measuring magnetic variables
    • G01R33/02—Measuring direction or magnitude of magnetic fields or magnetic flux
    • G01R33/06—Measuring direction or magnitude of magnetic fields or magnetic flux using galvano-magnetic devices
    • G01R33/07—Hall effect devices

Definitions

  • the invention relates to a method for measuring magnetic fields according to the preamble of the independent patent claim and a device for carrying out the method.
  • the technique of measuring magnetic fields with Hall probes is known from the literature.
  • List-Magnetik GmbH, D-7022 Leinfelden-Echterdingen, for example, offers a portable magnetic field measuring device under the name MP-U.
  • This device is suitable for measuring time-constant fields in both polarity directions (north and south poles), optionally also for measuring alternating fields.
  • the device has a selector switch for the display type (DC or AC field, as well as peak value memory) and the measuring range, also a key for resetting the peak value display and a rotary knob for setting the zero point.
  • a similar measuring device is manufactured by Walker Scientific Inc., Worcester, Massachusetts, USA, under the Dell MG-5DP offered. This device also has essentially the same operating elements: function selector, measuring range selector, peak value reset button and zero point setting button.
  • the display is digital on the front panel of the measuring device.
  • the magnetic field probe is connected to the device by a cable.
  • the selection of the measuring range requires an intervention on the measuring device, which distracts from the actual measuring task. Especially when diagnosing magnetic fields, areas of very different field strengths are repeatedly touched, which always requires a correction of the measuring range. For the peak value measurement, the magnitude of the value must be known in advance so that the display can be used .
  • the object of the invention is to provide a method which requires significantly fewer manual interventions and to automate the steps described above as far as possible.
  • a corresponding measuring device is proposed for carrying out the method, which simplifies operation in accordance with the method and only requires a minimum of interventions.
  • a further advantage of the method according to the invention is that, in the case of the automatic zero point setting and the corresponding measurement value compensation, the local earth magnetic field and any smaller interference fields which may be present are automatically taken into account and compensated for and do not distort the measurements.
  • Another advantage is that the measured values can be read both on the measuring device and on the probe body itself.
  • FIG. 1 shows the measuring device 1 with its essential operating elements.
  • FIG. 2 shows the individual function modules in their context.
  • the method for measuring magnetic fields with a magnetically sensitive probe which is introduced into a magnetic field to be measured and thereby emits a signal to a measuring device for evaluation, has the following steps in the following order: manual switching on of the measuring device, automatic zero point measurement and zero point setting with calculation of the correction value and its storage, manual insertion of the probe into a magnetic field to be measured, automatic polarity monitoring with feedback and corresponding switching of the measuring device, automatic peak value storage of the measured values with automatic adaptation of the measuring range to the Area of the magnetic field to be measured, reading of the measured values, manual removal of the probe from the magnetic field to be measured and manual or automatic switching off of the measuring device.
  • the measured value is read on a display panel on the measuring device or on the probe body.
  • the readings can also be automated via computers via an interface for data transfer.
  • a self-signal of the probe is used for the automatic zero point setting of the measuring device, which is emitted by the Hall probe after the measuring device is switched on, the measured value of the self-signal being stored and this value being compensated for all further measurements via a control amplifier. After any number of measurements, the zero point setting is carried out again.
  • the measurement signal is fed to a discriminator which distinguishes a magnetic field which is constant in polarity from a temporally changing polarity and which emits a corresponding signal which is used to control the further signal processing.
  • the mean value of the measurement signal is automatically formed and displayed.
  • the absolute value of the measurement signal is automatically generated and its mean value is displayed; or the rms value of the measurement signal is formed and displayed as required.
  • FIG. 1 shows the measuring device 1 with its essential operating elements.
  • the magnetic field to be measured is determined by the Hall probe 2 recorded, which generates a voltage proportional thereto.
  • the probe housing 3 is used for easy handling of the probe. It contains a multicolor display 4, in the form of light-emitting diodes with the two colors red and green, which, when illuminated simultaneously, result in the third color yellow.
  • the probe housing 3 also contains the push button 5 for selecting the function of the peak value display.
  • the entire probe is connected to the measuring device via the cable 6.
  • the measurement value is displayed on the digital LCD display 14 on the measuring device.
  • a further measured value display 14 ' is attached to the probe housing 3.
  • the measured value display 14 ' is in the form of a qualitative display which only indicates the measured area in stages. A number of LEDs also indicate the order of magnitude of the measured values. In another embodiment, the measured value display 14 'is designed as a quantitative display with an LCD so that the measured values are displayed digitally in the same way as with the measured value display 14 on the measuring device.
  • the device is put into operation with the on / off switch 7.
  • the socket 21 serves to connect an external supply as an alternative to the internal battery 20.
  • the amplified signal of the Hall probe can be tapped off at the external measuring connection 26, for example for the further one Examination with an oscilloscope.
  • FIG. 2 shows the individual function modules in their context. With the exception of the amplifier and the supply, the functions shown can be implemented with individual digital circuits or with a microprocessor. In the second case, the functions are not realized physically, but in the form of program sections. The sequence shown here follows the first variant.
  • the measurement signal supplied by the Hall probe 2 is amplified in the amplifier 8, the amplification itself being adjustable in stages in order to be able to detect magnetic fields of different orders of magnitude without problems.
  • This step-by-step setting is carried out by means of the range selection function 10.
  • the output signal of the amplifier is brought to the output socket for the external measurement 26 without further conversion.
  • the amplified measurement signal is now brought directly to the function selector 11 via the measurement rectifier 9.
  • the measuring rectifier 9 is preferably designed as an effective value generator.
  • Known integrated circuits for example the type AD 636 from the manufacturer Analog Devices, are available for this. With the conversion into the effective value the Force effect of the magnetic field, which is based on a quadratic relationship between field strength and force, is particularly well represented.
  • the function selector 11 is controlled by the AC / DC discriminator 19 in such a way that when a signal with constant polarity is present, the measurement signal supplied by the amplifier 8 is passed on directly. If the polarity changes rapidly, the AC / DC discriminator 19 generates a control signal with the meaning "alternating field". In this case, the function selector 11 takes over the signal converted via the measurement rectifier 9.
  • the measurement signal reaches the peak value memory 12. This is controlled by the mode selector 28.
  • the peak value memory 12 has three different operating modes: immediate display, peak value positive, peak value negative.
  • the peak value memory is out of operation for immediate display. To display the peak value, its output signal follows the input signal until a maximum is reached, which is then stored and is permanently present at the output until either an even higher value is measured or until the memory is deleted by resetting to the immediate display.
  • the measurement signal reaches the digital voltmeter 13, which in turn controls the LCD display 14.
  • Both components are electronic components Known and customary.
  • Range evaluation 15 is provided for automatic switching of the measuring range. This ensures that when the measurement signal is low, a more sensitive measuring range, that is to say a larger amplification in the amplifier 8, is selected, while if the measuring range of the digital voltmeter 13 is exceeded, a less sensitive measuring range with a correspondingly lower amplification is determined.
  • the automatic range evaluation controls the range selection 10 of the amplifier on the one hand, and the position of the decimal point on the display via the decimal point control 25 on the other hand.
  • the measurement signal is preferably evaluated in two ways: exceeding the measurement range by evaluating the corresponding output signal of the digital voltmeter 13, falling below by monitoring the amplified measurement signal after the function selector 11.
  • the measurement always begins with the most sensitive area. In the case of the peak value measurement, switching back to a more sensitive area must be blocked. This is done by a corresponding signal from the mode selector 28.
  • the vote is carried out in a particularly convenient manner by inserting the probe into an appropriate magnetic field and briefly pressing the button 5.
  • signal is evaluated in the key evaluation 27 and arrives at the mode selector 28. This receives the information about the polarity of the signal from the polarity monitor 16 when the key is pressed. If there is a constant negative polarity, the peak value memory 12 is activated to detect the negative peak value laid and held. In the case of positive or rapidly changing polarity (alternating field), the peak value memory 12 is fixed on the detection of the positive peak value.
  • the measuring rectifier 9 always delivers a positive output signal.
  • the reset of the peak value memory 12 to the immediate display mode of operation takes place either by pressing the button again briefly or by a timer for the automatic reset 29. This ensures that the measuring device always comes back on after not being used for one minute, for example the immediate display jumps back.
  • This function supports the automatic switch-off of the device when not in use, which will be described later, and prevents misinterpretation of the display.
  • the peak value function type is also indicated on the LCD display by a special symbol.
  • the polarity of the measurement signal is detected directly on the output signal of the Hall probe 2 with the polarity monitor 16.
  • This provides a three-concept signal: Hall signal positive, Hall signal negative, Hall signal zero (or very small). These three terms are prepared in the LED control 17 for operating the multicolor display 4.
  • the signal positive brings the red color of the LED to light, the signal negative corresponds to the green color. With rapidly changing polarity this results in the mixed color yellow.
  • the three-aspect signal is also used for controlling the AC-DC discriminator 19 and the mode selector 28.
  • the particular advantage of this * circuit is that the user at Auf ⁇ light of more dyeing display can see at a glance what kind of peak memory with the Keystroke is selected.
  • the device is powered from the battery 20 or external feed connector 21 in a known manner. In order to avoid excessive battery consumption, the device is switched off with the automatic switch 18 if the Hall probe 2 does not provide a signal which is clearly distinguishable from zero for a prolonged period.
  • the range evaluation 15 emits a corresponding signal which is always present in the deepest, that is to say the most sensitive measuring range, as long as no measurement is taking place. This time is monitored in a time switch, which is reset when the switching point is exceeded, but otherwise switches the device off after the time period of, for example, a few minutes.

Landscapes

  • Physics & Mathematics (AREA)
  • Condensed Matter Physics & Semiconductors (AREA)
  • General Physics & Mathematics (AREA)
  • Measuring Magnetic Variables (AREA)

Abstract

Appareil de mesure des champs magnétiques, caractérisé par le réglage à zéro automatique lors de sa mise en marche, la sélection automatique de la plage de mesure, la commutation automatique de l'affichage entre un champ constant dans le temps et un champ alternatif et, au choix, l'affichage de la valeur de crête. La manoeuvre est commandée par un bouton-poussoir unique sur le corps de sonde. Le type de champ est affiché par un voyant-témoin multicolore sur la sonde.
EP93907742A 1992-05-11 1993-04-16 Appareil de mesure des champs magnetiques Withdrawn EP0593701A1 (fr)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
CH149992 1992-05-11
CH1499/92 1992-05-11
PCT/CH1993/000098 WO1993023761A1 (fr) 1992-05-11 1993-04-16 Appareil de mesure des champs magnetiques

Publications (1)

Publication Number Publication Date
EP0593701A1 true EP0593701A1 (fr) 1994-04-27

Family

ID=4211886

Family Applications (1)

Application Number Title Priority Date Filing Date
EP93907742A Withdrawn EP0593701A1 (fr) 1992-05-11 1993-04-16 Appareil de mesure des champs magnetiques

Country Status (3)

Country Link
US (1) US5608319A (fr)
EP (1) EP0593701A1 (fr)
WO (1) WO1993023761A1 (fr)

Families Citing this family (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
USD391877S (en) 1997-05-16 1998-03-10 John Cassidy Electrical field detector
DE19809076A1 (de) * 1998-03-04 1999-09-09 Haase Gerät zur Messung magnetischer Felder
US6486664B1 (en) 1998-07-01 2002-11-26 Lepel Corp. Magnetic field exposure sensor and analysis system
EP1014101A3 (fr) * 1998-12-21 2004-11-03 Sura Magnets AB Appareil d'essai magnétique
CN104793151B (zh) * 2015-04-16 2017-08-01 三峡大学 一种磁性元件的磁场测量装置及测量方法
LU93151B1 (en) * 2016-07-15 2018-01-23 Luxembourg Inst Science & Tech List Hall Probe
USD949106S1 (en) * 2019-11-18 2022-04-19 Maurer Magnetic Ag Demagnetization apparatus

Family Cites Families (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3600678A (en) * 1969-09-12 1971-08-17 Jim C Garrett Solid-state polarity tester for telephone equipment
US4166245A (en) * 1977-11-14 1979-08-28 Loft Modular Devices, Inc. Simultaneous display of multiple characteristics of complex waveforms
US4550287A (en) * 1983-08-11 1985-10-29 The Boeing Company Data bus test instrument having a tri-colored LED and indicating continuity, voltage and polarity
GB2171207A (en) * 1985-02-16 1986-08-20 Eja Eng Co Portable magnetic field detector
EP0438637A1 (fr) * 1990-01-24 1991-07-31 Landis & Gyr Business Support AG Procédé et dispositif pour la détection de la valeur effective Ieff d'un courant à mesurer utilisant un élément Hall et un circuit d'amplification
US5343145A (en) * 1991-04-09 1994-08-30 Crown Equipment Corporation Method and apparatus for monitoring the proper operation of a hall effect device used in detecting buried magnets in a control system for materials handling vehicles
DE4139855A1 (de) * 1991-12-03 1993-06-09 Kabushiki Kaisha Sanwa Keiki Seisakusho, Akishima, Tokio/Tokyo, Jp Analog-messgeraet mit automatischer bereichswahl

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
See references of WO9323761A1 *

Also Published As

Publication number Publication date
US5608319A (en) 1997-03-04
WO1993023761A1 (fr) 1993-11-25

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