Bartington Mag-01H, Operation Manual

Page 1: ...Operation Manual for Mag 01H Fluxgate Declinometer Inclinometer with non magnetic Wild T1 Theodolite ...

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Page 3: ... 13 5 2 Steep Sighting Prisms 13 5 3 Objective Sun and Orange Filters 13 6 Taking Measurements 14 6 1 Magnetic Hygiene 16 6 2 Theodolite Set up 16 6 2 1 Levelling the Theodolite 16 6 2 2 Setting Over A Reference Point Tripod Mounted 17 6 2 3 Setting Over A Reference Point Pillar Mounted 17 6 3 Performing Observations of D I with A Non Resettable Horizontal Circle Theodolite 18 6 4 Taking Readings ...

Page 4: ... 25 7 3 2 Probe Electrical Resistance Values 25 7 4 Mag 01H Battery Replacement 25 7 5 Probe Alignment 26 7 5 1 Method 26 7 6 Offset Trimming 27 7 7 Cleaning the D I System 27 8 Storage and Transport 28 9 End of Life Disposal 28 9 1 Waste Electrical and Electronic Equipment WEEE Regulations 29 Appendix 1 Observatory D I Record Sheet 30 Appendix 2 Example International Geomagnetic Reference Field 3...

Page 5: ...RNING Indicates a situation in which serious bodily injury or death could result if the warning is ignored Caution Indicates a situation in which bodily injury or damage to your instrument or both could result if the caution is ignored Identifies items that must be disposed of safely to prevent unnecessary damage to the environment Note A note provides useful supporting information and sometimes s...

Page 6: ...obile observatory use enabling highly detailed mapping of D and I See Taking Measurements for further details of taking measurements The system is used in observatories to obtain reference data which may be used in the construction of Reference Field Charts See Appendix 2 for an example of an International Geomagnetic Reference Field IGRF chart Note The Earth s magnetic field is constantly changin...

Page 7: ... connecting the probe to the magnetometer does not interfere with the measurement procedure and will operate down to very low temperatures 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 practice u...

Page 8: ...erally vary with latitude Example where F 47 000nT I 67 On x1 sensitivity 1nT RdI circa 5 seconds RdD circa 10 seconds On x10 sensitivity 0 1nT RdI circa 0 5 seconds RdD circa 1 0 seconds Note These are theoretical values and actual values will be determined by prevailing conditions From the IGRF chart in Appendix 2 it can be seen that resolution in Declination is at a minimum at the poles and at ...

Page 9: ...ure gasket 7 5m cable to magnetometer 3 Blanking plates 8 Enclosure mounting screws 4 Enclosure 9 Fluxgate Mag A probe 5 Mounting plate screws 10 Probe mounting screws The probe consists of a precision fluxgate magnetic field sensor mounted within a tube A joystick arrangement for trimming the alignment of the sensor relative to the tube is provided The probe is mounted on a pillar enclosed in a r...

Page 10: ...tains 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 Other equipment operating in the area is therefore unlikely to be affected Note The unit itself is also unlikely to be affected by i...

Page 11: ...gure 2 11 High flexibility cable to magnetometer 17 Pillar mount adaptor Trivet 12 Probe 18 Vertical circle adjustment 13 Micrometer 19 Tubular level 14 Vertical circle clamp 20 Scale focusing ring 15 Horizontal circle adjustment 21 Graticule focusing ring 16 Horizontal circle clamp 22 Telescope focusing ring 15 13 12 11 16 14 21 19 18 17 22 20 ...

Page 12: ...ighting prism Scale non inverting 29 Levelling screws 25 Steep sighting prism Tekescope 30 Circular level 26 Scale illuminator mirror 31 Optical plumb 27 Tubular level adjuster 32 Solar or orange filter The Wild T1 is a 6 second accuracy non magnetic theodolite The accuracy stated is for the mean square of a single Circle Left CL measurement and a single Circle Right CR 23 29 31 25 27 24 30 32 26 ...

Page 13: ...5 2 Steep Sighting Prisms When performing steep angled telescopic observations or attempting to perform null mode magnetic measurements for shallow angles of I a pair of steep sighting prisms will be required These will extend the vertical viewing angle from circa 40 to 18 There are two types of prism The larger type fits the telescope eyepiece and results in an inverted image The smaller prism fi...

Page 14: ...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 Figure 4 describes the conventions in making observations for identifying the directions of observation when performing null mode measurements Figures 5 and 6 give further details of the null mode ...

Page 15: ...ircle Key to Figure 6 I Angle of inclination I DIP is the vertical angle of the terrestrial field F relative to the horizontal plane The plane of the vertical circle is set parallel to the magnetic meridian MM O The horizontal datum O is determined by the pendulum compensated vertical reference Z In Figures 5 and 6 E W N and S refer to the direction in which the telescope is pointed while U and D ...

Page 16: ...ubsequently for record purposes 6 1 Magnetic Hygiene Note Before attempting magnetic observations ensure adequate personal magnetic hygiene For example garments should be free from steel fasteners or buckles Magnetic hygiene can be checked when commencing observations by moving hands head and torso close to the probe and observing any change in reading Readings should not vary by more than 0 2nT I...

Page 17: ...round reference point with its head level Mount the theodolite and level the instrument using the circular plate level and foot screws 2 To focus the optical plummet tripod only on the graticule turn the eyepiece and focus on the ground point by pulling or pushing the eyepiece tube Line up the graticule and target point by adjusting the tripod legs and or instrument foot screws as necessary 3 Re l...

Page 18: ...to assist with data reduction An accurate digital clock with a large display positioned away from the theodolite is also required The observation conventions are described pictorially in Figures 4 5 and 6 Two optical and four magnetic measurements are performed for each observation and the results are averaged to eliminate system optical and magnetic errors Worked examples are given at the end of ...

Page 19: ...ould 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 Note A small offset error a few nT will be present when switching between the x1 and x10 sensitivity settings This in no way affects observation accuracy provided that the sensitivity setting is not changed du...

Page 20: ...rtical circle to 90º or 270º as appropriate ensuring the micrometer scale reads 00 00 see Figure 9 Perform the four null mode magnetometer observations and calculate the Magnetic Meridian mean value MM Where MM ED WD EU WU 4 3 Calculate the Declination D Where D MM TA TD 90º Select the value expected for D and reject the larger value Note D will be positive if to the east and negative if to the we...

Page 21: ... of D and lock the horizontal circle 2 Rotate the telescope in the vertical plane and obtain the NU and SD null magnetic measurements 3 Rotate the telescope to MM or MM 180º on the horizontal circle corresponding to the south observation of D Lock the horizontal circle and rotate the telescope in the vertical plane to obtain the SU and ND null magnetic measurements 4 Calculate the Inclination I Wh...

Page 22: ...d be avoided as the bearing journals in this type of theodolite are manufactured from phosphor bronze and are not as strong as those manufactured in steel 7 1 Checking the System 7 1 1 Battery Check Connect the battery charger to a live supply The charge indicator on the magnetometer should illuminate After 10 to 20 minutes switch on the magnetometer The battery voltage is shown for a few seconds ...

Page 23: ... 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 As a guide offset errors should not exceed 5nT per annum 7 3 Probe Cable Repairs Figure 10 Mag 01H internal view ...

Page 24: ... 32 OM2020 5 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 48 47 46 45 44 39 40 41 42 43 ...

Page 25: ...nged If the cable is suspected check the electrical resistance using a suitable meter and with reference to the values in Probe Electrical Resistance Values below 7 3 1 Replacing the cable The cable can be replaced in the following way 1 Remove probe cover screws 2 De solder the four wires from the tag strip 3 Release the screw that retains the earth lead 4 Unscrew the cable gland 5 Reconnect in t...

Page 26: ... remove the protective cover at the cable gland end of the probe enclosure The probe collimation joystick adjuster is clamped by two screws which act against a clamping plate at the base of the joystick These screws should be slackened one half turn each using the non magnetic screwdriver adjusting tool provided with each new system to free the joystick Some practice will be required to obtain the...

Page 27: ...ence of an offset error these values will not be 180o apart 4 Adjust the vertical circle to a value which is the mean of SU and ND ND SU 180 2 5 Adjust the x10 offset potentiometer item 35 in Figure 10 to produce a displayed magnetometer value of 00000 6 Select x1 sensitivity 7 Adjust x1 offset potentiometer item 34 in Figure 10 to produce a value of 0000 7 7 Cleaning the D I System Caution To cle...

Page 28: ...dry before storage Caution The theodolite should be stored in a dry environment The theodolite must not be placed in an environment where condensation or moisture can deposit inside the unit underneath a glass bell jar or in a damp case as this will promote the growth of mould If this occurs then the alignment of the circle and optics can be affected Note If storing the equipment in a permanently ...

Page 29: ...M2020 5 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 30: ...IRCLE TIME TD UT Degrees Minutes Seconds Hours Minutes Seconds E D W D E U W U MM ED WD EU WU 4 MEAN TIME TD TED TWD TEU TWU 4 Degrees Minutes Seconds Hours Minutes Seconds MM TD D MM TA TD 90 D Degrees Minutes Seconds INCLINATION Degrees Minutes Seconds Degrees Minutes Seconds MM MM 180 NULL ANGLE VERTICAL MEAN TIME TI UT Degrees Minutes Seconds Hours Minutes Seconds N U S D S U N D I 360 ND 180 ...

Page 31: ...BARTINGTON INSTRUMENTS Page 31 of 32 OM2020 5 Appendix 2 Example International Geomagnetic Reference Field Figure A2 1 Example international geomagnetic reference field ...

Page 32: ...gton Instruments Limited in the following countries United Kingdom Australia Brazil Canada China European Union India Japan Norway and the United States of America Bartington Instruments Limited 5 Thorney Leys Business Park Witney Oxford OX28 4GE England www bartington com T 44 0 1993 706565 F 44 0 1993 774813 E sales bartington com ...