Bartington Mag-01H Operation Manual

Fluxgate declinometer/inclinometer with non-magnetic wild t1 theodolite
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Operation Manual for
Mag-01H Fluxgate Declinometer/Inclinometer
with non-magnetic Wild T1 Theodolite

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Summary of Contents for Bartington Mag-01H

  • Page 1 Operation Manual for Mag-01H Fluxgate Declinometer/Inclinometer with non-magnetic Wild T1 Theodolite...
  • Page 2 THIS PAGE BLANK...
  • Page 3: Table Of Contents

    BARTINGTON INSTRUMENTS Table of Contents 1. About this Manual 1.1. Symbols Glossary 2. Safe Use 3. Introduction 3.1. The Null Method of Measurement 3.2. Resolution 4. The Magnetometer 4.1. Magnetometer Operation and Controls 4.2. The Probe 4.3. Electromagnetic Compatibility 5. The Theodolite 5.1.
  • Page 4 7.1.3. Theodolite Optical Check 7.2. Calibration 7.3. Probe Cable Repairs 7.3.1. Replacing the cable 7.3.2. Probe Electrical Resistance Values 7.4. Mag-01H Battery Replacement 7.5. Probe Alignment 7.5.1. Method 7.6. Offset Trimming 7.7. Cleaning the D/I System 8. Storage and Transport 9.
  • Page 5: About This Manual

    BARTINGTON INSTRUMENTS 1. About this Manual This document describes the installation, operation and maintenance of the Mag-01H Fluxgate Declinometer/Inclinometer (D/I) System. It should be read in conjunction with: • the product brochure DS0070 • operation manual OM0382, which describes the operation of the Mag-01H magnetometer • the WildT1 theodolite...
  • Page 6: Introduction

    3. Introduction The Mag-01H Declinometer/Inclinometer (D/I) System comprises a high sensitivity, battery powered, magnetometer type Mag-01H together with a vector sensing fluxgate Mag A probe which is mounted on a Wild T1 non-magnetic theodolite. The system permits very precise angular measurements of the terrestrial magnetic field F. The angular components measured are Declination D and Inclination I.
  • Page 7: The Null Method Of Measurement

    Note: The use of low magnetic signature components within the Mag-01H instrument enables this unit to be used close to the probe head. Errors will not be significant with the probe and magnetometer as close as 0.5 metres, although the magnetometer is, in...
  • Page 8 BARTINGTON INSTRUMENTS Note: At any magnetometer resolution, resolution of Inclination I is dependent on the magnitude of F alone, whereas resolution of Declination D is dependent on H and I and will generally vary with latitude. Example (where F = 47,000nT, I = 67°):...
  • Page 9: The Magnetometer

    BARTINGTON INSTRUMENTS 4. The Magnetometer 4.1. Magnetometer Operation and Controls operation manual OM0382 for a description of the Mag-01H’s operation, and a description of the front and rear panel controls. 4.2. The Probe Figure 1. Theodolite mounted Mag A probe assembly.
  • Page 10: Electromagnetic Compatibility

    4.3. Electromagnetic Compatibility The Mag-01H instrument contains no high frequency electronics likely to cause emissions which could affect other apparatus. The design, including the use of a rechargeable battery (charged from a mains adaptor) and the decoupling of internal power supplies, is intended to produce minimal emissions.
  • Page 11: The Theodolite

    BARTINGTON INSTRUMENTS 5. The Theodolite Figure 2. Non-magnetic Wild T1 theodolite key operational features, view 1. Key to Figure 2 11. High flexibility cable to 17. Pillar mount adaptor (Trivet) magnetometer 12. Probe 18. Vertical circle adjustment 13. Micrometer 19. Tubular level 14.
  • Page 12 BARTINGTON INSTRUMENTS Figure 3. Non-magnetic Wild T1 theodolite key operational features, view 2. Key to Figure 3 23. Vertical circle housing 28. Horizontal circle housing 24. Steep sighting prism (Scale: non- 29. Levelling screws inverting) 25. Steep sighting prism (Tekescope) 30.
  • Page 13: Night Viewing

    The scale illumination lamp unit supplied by Wild is unsuitable due to its magnetic signature. The alternative, recommended and supplied by Bartington, is a chemiluminescent light stick. These are approximately 47mm length x circa 6 mm diameter. Bend the light stick to activate it and place between the theodolite mirror and window to provide illumination.
  • Page 14: Taking Measurements

    BARTINGTON INSTRUMENTS 6. Taking Measurements This section describes the procedures for measurement of Declination and Inclination in the null mode. Four readings are obtained for calculation of D and four readings are obtained for calculation of I. Each set of four comprises two pairs of readings. One pair is averaged to eliminate electronic offset errors and the other pair is averaged to eliminate mechanical alignment errors (probe collimation).
  • Page 15 BARTINGTON INSTRUMENTS Figure 5. Observations of Declination in the horizontal circle. Key to Figure 5 D. Angle of declination D (variation) is the azimuth angle between the geographical meridian GM and the magnetic meridian MM. F. The direction of the terrestrial field.
  • Page 16: Magnetic Hygiene

    BARTINGTON INSTRUMENTS Declination is calculated from the mean of the four observations ED, WD, EU, WU. The reference observation for Declination is the Geographical Meridian (GM) obtained using a Circle Left / Circle Right observation to eliminate optical collimation errors.
  • Page 17: Setting Over A Reference Point (Tripod Mounted)

    BARTINGTON INSTRUMENTS 2. Rotate the telescope to a horizontal position with the probe at the top and apply the vertical clamp. Release the horizontal clamp and align the tubular level between any two foot-screws A and B. Foot screws A and B should be turned in opposite directions by equal amounts until the tubular level is centred.
  • Page 18: Performing Observations Of D&I With A Non-Resettable Horizontal Circle Theodolite

    BARTINGTON INSTRUMENTS 3. Rotate to the next pair of levelling screws and repeat the adjustment. 4. Rotate and continue adjustment until the desired accuracy is achieved. 6.3. Performing Observations of D&I with A Non-Resettable Horizontal Circle Theodolite The re-settable circle previously provided on the steel equivalent theodolite is not required for accurate measurement of D and I and has been eliminated.
  • Page 19: Performing Observation Of Declination

    (0.1nT resolution). If noise exceeds 0.5nT p-p then x1 sensitivity setting should be used. This is recommended for most observations. Note: Before taking readings on the Mag-01H, ensure that the offset control is set to zero and the toggle switch is in a central position.
  • Page 20 BARTINGTON INSTRUMENTS and clamp both circles. Then use the vertical and horizontal circle adjustment controls to align with the target. 1. Observe the target and record both the circle left (CL) and circle right (CR) horizontal circle readings. Calculate the target datum (TD) as follows: TD(±90°)
  • Page 21: Performing Observation Of Inclination

    BARTINGTON INSTRUMENTS 170º (ED+ WD + EU + WU)/4 (194º + 14º + 14º + 194º)/4 104º MM + (-30°) - TD ± 90° 104º - 30º - 170º + 90º = - 6º - Select 104º - 30º- 170º - 90º = - 186º - Reject 6.6.
  • Page 22: Repair And Maintenance

    Maintenance procedures are restricted to probe cable test and repair, and replacement of the Mag-01H battery. Beyond this, no repair or servicing is possible with the Mag-01H D/I system. When service or maintenance is required, contact Bartington Instruments. However, a full calibration service is offered by Bartington Instruments, together with optional certification at an observatory.
  • Page 23: Calibration

    BARTINGTON INSTRUMENTS 7.2. Calibration Return the D/I System to Bartington Instruments for magnetometer calibration at the recommended intervals. Refer to the Calibration Certificate for further details. If mechanical misalignment is suspected during magnetometer calibration, Bartington Instruments’ Service Department will contact you to suggest further tests. Mechanical misalignment resulting from wear and tear cannot be predicted, but additional periodic recalibration of the theodolite is recommended.
  • Page 24 BARTINGTON INSTRUMENTS Key to Figure 10 33. Battery 6V 1.2Ah lead acid gel type 37. VR1 precision reference adjustment 34. VR3 x1 O/S 38. Ribbon cable 35. VR2 x10 O/S. VR = variable resistor C1. Brown 36. DPM scaling C8. Grey...
  • Page 25: Replacing The Cable

    + Fb to - Fb 230 ± 10 Ex to Ex 20 ± 3 7.4. Mag-01H Battery Replacement See Figure 10 for battery location. If the battery fails then it can be replaced as follows: 1. Remove the top of the case.
  • Page 26: Probe Alignment

    2. Carefully level the theodolite. Switch on the magnetometer and adjust to obtain high resolution. Set the vertical circle to precisely 180º using the vertical scale and note the reading on the Mag-01H. 3. Release horizontal circle and rotate the theodolite.
  • Page 27: Offset Trimming

    BARTINGTON INSTRUMENTS 6. Repeat steps (1) to (5), whilst gently re-tightening the clamping screws, until the difference between two readings and each pair of readings is circa 1nT. Light finger tightness only should be used. 7. Replace probe protective cover and four retaining screws.
  • Page 28: Storage And Transport

    This product should not be disposed of in domestic or municipal waste. For information about disposing of your sensor safely, check local regulations for disposal of electrical / electronic products. Alternatively contact Bartington Instruments to arrange the return of products for disposal. Where returning the instruments is not possible, you should check local regulations for disposal of electronic products.
  • Page 29: Waste Electrical And Electronic Equipment (Weee) Regulations

    BARTINGTON INSTRUMENTS 9.1. Waste Electrical and Electronic Equipment (WEEE) Regulations The Bartington D/I System complies fully with RoHS (Reduction of Hazardous Substances) legislation. However, electronic equipment should never be disposed of in normal waste. Page 29 of 32 OM2020/5...
  • Page 30: Appendix 1: Observatory D/I Record Sheet

    BARTINGTON INSTRUMENTS Appendix 1: Observatory D/I Record Sheet OBSERVATORY Observatory D/I Record Sheet DATE OBSERVER Degrees Minutes Seconds T.A. DECLINATION Degrees Minutes Seconds Degrees Minutes Seconds TD(±90°)= (CL+CR)/2 Degrees Minutes Seconds TD(±90°)= NULL ANGLE HORIZONTAL CIRCLE TIME T (UT) Degrees...
  • Page 31: Appendix 2: Example International Geomagnetic Reference Field

    BARTINGTON INSTRUMENTS Appendix 2: Example International Geomagnetic Reference Field Figure A2.1. Example international geomagnetic reference field. Page 31 of 32 OM2020/5...
  • Page 32 The copyright of this document is the property of Bartington Instruments Ltd. Bartington® is a registered trade mark of Bartington Instruments Limited in the following countries: United Kingdom, Australia, Brazil, Canada, China, European Union, India, Japan, Norway and the...

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