Bartington Mag585 User manual
BARTINGTON INSTRUMENTS
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Table of Contents
1. Legal notices 4
1.1. Copyright 4
1.2. Trademarks 4
1.3. Warranty and Terms & Conditions 4
2. How to use this manual 4
2.1. Symbols glossary 4
3. Safe use 5
4. Introduction to the Mag585 and Mag592 5
4.1. Vector measurements and conventions 5
5. Installing the Mag585 and Mag592 6
5.1. Siting the magnetometer (environment recommendations) 6
5.2. Connection recommendations 7
5.2.1. Connector pin allocation 7
5.2.2. Interface 7
5.2.3. Power supplies 7
5.3. Pre-installation tests 7
5.4. Mounting recommendations 8
5.5. Post installation testing 8
6. Using the Mag585 and Mag592 8
6.1. Cabling 8
6.2. Connecting power 9
6.3. Electromagnetic compatibility 9
6.4. Performance 9
6.4.1. Signal processing 9
6.5. Magnetic hysteresis 10
6.6. Environmental precautions 10
7. Troubleshooting 10
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8. Care and maintenance 11
8.1. Cleaning the Mag585 and Mag592 11
8.2. Calibration 11
9. Storage and transport 12
10. End of life disposal 12
10.1. Waste Electrical and Electronic Equipment (WEEE) Regulations 12
Appendix 1: Use of Alternative Power Supplies 12
A1.1. Signal/power ground 13
A1.2. Recommended connection method 14
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1. Legal notices
1.1. Copyright
The copyright of this document is the property of Bartington Instruments Ltd.
1.2. Trademarks
Bartington® is a trademark of Bartington Instruments Ltd in Australia, Canada, China, the
European Community, India, Japan, the countries of the Madrid Agreement & Protocol™, Norway
and the United States of America.
1.3. Warranty and Terms & Conditions
This document should be read in conjunction with the Terms & Conditions for the Supply of
Goods and Services, which also describe the terms of warranty. They are available at www.
bartington.com/terms-and-conditions.html.
Bartington Instruments reserves the right to change any part of the design of these products
without prior notice.
2. How to use this manual
This document describes the installation, operation and maintenance of the Mag585 and Mag592
Magnetic Field Sensors.
Take the time to get well acquainted with your purchase by reading this manual. Knowing and
understanding your sensor will ensure you experience the most reliable operation.
When service or maintenance is required, contact the Bartington Instruments service team.
Technical specifications for these products can be found in the appropriate product brochures on
the product pages of the Bartington Instruments website:
www.bartington.com/mag585-low-radiation-three-axis-magnetic-field-sensor.html
www.bartington.com/mag592-low-radiation-single-axis-magnetic-field-sensor.html
2.1. Symbols glossary
The following symbols used within this manual call your attention to specific types of
information:
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WARNING: 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: Provides useful supporting information on how to make better use of your purchase.
3. Safe use
WARNING: These products are not qualified for use in explosive atmospheres or life
support systems. Consult Bartington Instruments for advice.
4. Introduction to the Mag585 and Mag592
The Mag585 is a magnetometer consisting of three feedback stabilised fluxgate sensors
arranged along X, Y and Z axes. Each axis provides a highly linear magnetic response with low
hysteresis and low cross talk between axes.
The Mag592 is a single axis equivalent, providing precision measurements of the intensity of
static and slowly varying magnetic fields in one direction.
The Mag585 and Mag592 are cost effective sensors suitable for many general purpose
applications. High stability circuitry ensures that a minimum of ten years’ service should be
expected.
The sensors have no power supply or data processing abilities of their own and must always be
connected to a power supply to be able to operate.
4.1. Vector measurements and conventions
The Mag585 produces three independent analogue output voltages in response to the magnitude
and direction of the orthogonal components of a magnetic field. A ‘right-hand’ co-ordinate
system is adopted (Figure 1). In this system, the X, Y and Z axis correspond to the thumb, first
and second finger respectively of the right hand. By convention, the magnetometer should be
installed so that the X axis is arranged to point north, the Y axis to point east and the Z axis to
point down.
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Figure 1. Illustration of the Right Hand Rule
The centres of the three vector sensors are superimposed. Each orientation is denoted on the
magnetometer’s label. The point of each vector arrow indicates the positive direction of each
axis.
5. Installing the Mag585 and Mag592
5.1. Siting the magnetometer (environment recommendations)
Note: Site the magnetometer several metres from any magnetic base rock to avoid
compromising measurements.
Note: Site the magnetometer several tens of metres from very large ferromagnetic objects
that could create fields exceeding the measuring range of the sensor.
Note: Avoid siting the sensor near any ferromagnetic objects that may be subjected to the
effects of magnetic hysteresis, which would affect the sensor in an unpredictable manner.
Note: Conduct a magnetic evaluation of any proposed installation site to establish that
it is free from magnetic contaminants. Carry out such an evaluation using total field or
resonance magnetometers.
North
+X
Thumb
Down
+Z
2nd Finger
East
+Y
1st Finger
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5.2. Connection recommendations
5.2.1. Connector pin allocation
The connector pin or cable colour allocation for the connection to each package type is shown on
the appropriate outline drawing on the product page.
5.2.2. Interface
X, Y and Z outputs are protected against short circuit to 0V.
Caution: Short circuits from output to either power rail may result in permanent damage to
the sensor. Limit the power supply current to 100mA to minimise risk of damage caused by
incorrect connection.
The analogue outputs for the X, Y and Z axes are buffered to give a low output impedance,
enabling the unit to be operated over long cables and interfaced to low impedance data
acquisition systems.
5.2.3. Power supplies
The Bartington PSU1, Magmeter, SCU1 and Spectramag-6 are ideal power supply units.
Alternatively, users may wish to provide their own power supply. Refer to Appendix 1 for further
information.
5.3. Pre-installation tests
Prior to the installation of the system, the magnetometer, cable and power supply must be fully
tested to ensure correct function as follows:
Caution: Take care to avoid bending or otherwise damaging the contacts whilst conducting
the tests.
Caution: Carefully check for correct connection before applying power. Applying incorrect
polarity or power to output connections may cause irreparable damage to the sensor.
1. Test the cables for continuity (using an electrical continuity tester or ohmmeter).
a. Test the cables end to end at the connectors to ensure that the correct pins have been
allocated to the conductors and that there are no open or high resistance circuits.
a. Test the cables at the connectors to ensure that there are no short circuits between the
conductors.
2. Check the power supply output voltage using a voltmeter. Refer to the product brochure for
the required values.
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Caution: Switch off the power supply before connecting to the Mag585 and Mag592.
3. Connect the magnetometer to the cable connector.
4. Connect the power supply to the other cable connector.
5. Switch on the power supply and wait until the magnetometer has stabilised.
5.4. Mounting recommendations
Each magnetometer has a set of mounting holes to allow attachment to a stable base of fixture.
Refer to the mechanical drawings on the product page for details.
5.5. Post installation testing
1. Site the magnetometer and install the power supply and cabling.
2. Switch on the power supply and wait until the magnetometer has stabilised.
3. Confirm no magnetic objects are moving in the vicinity.
4. Monitor the sensor outputs.
5. Confirm that the sum of the measured magnetic field vectors is similar to the expected local
earth field.
6. Using the Mag585 and Mag592
6.1. Cabling
Note: The connecting cable to the sensor should be an eight-core screened cable. Two
cores will be used for positive and negative power supply lines, three cores for output
signals, one core for signal common and one for power supply ground. The screen should
be connected to supply ground at the supply end only. The capacitance between cores
should be less than 200pF per metre. A cable with individually shielded cores should be
considered for long cable applications.
Note: Leads are susceptible to EM interference and should be screened wherever possible.
Note: The length of the cable is limited by the voltage drop in the power supply lines
and the capacitance between the cores. For this reason the cable should be limited to a
maximum length of 600 metres.
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Bartington Instruments can supply cables for connection of the sensor to the PSU1, Magmeter,
SCU1 and Spectramag-6.
6.2. Connecting power
Caution: Check that the polarity of the supply is correct. The power supply should
be connected to the sensor before the supply is energised as this prevents high
surge currents which could cause damage. Apply the positive and negative supplies
simultaneously and avoid leaving the sensor connected to one polarity only.
6.3. Electromagnetic compatibility
Note: The Mag585 and Mag592 are not shielded for immunity from, or emission of,
electromagnetic fields. Any shield placed around the sensor will limit the bandwidth of the
sensor response. The emissions generated are at a low level with a primary frequency of
12.8kHz, being the frequency of the energising field of the sensor. The sensor is required to
respond to magnetic fields within the specified frequency band.
Note: Ensure that the sensor is not operated in areas where a high electromagnetic field
exists, even if the frequency is above the bandwidth of the sensor, as false information may
appear due to aliasing. This effect is seen in data acquisition systems when the frequency
of sampling is lower than the frequency of the signal which is being sampled. It may
produce apparent signals at lower frequencies than the noise, which may be within the
frequency band of the sensor. Similarly, do not place the sensor near to any equipment
which may be affected by the fields produced by the sensor excitation.
6.4. Performance
6.4.1. Signal processing
For different applications it may be necessary to process the signal from the sensor in different
ways.
a. In order to increase the sensitivity of the recording system, it may be necessary to back-
off the earth’s field and amplify only the changes in the field from the current value. This
requires a high-pass filter, which could be a simple capacitively coupled arrangement or a
multi-pole filter to provide a steep roll-off characteristic. These features are all present in
the SCU1 signal conditioning unit.
The output from all fluxgate sensors will contain noise from the driving electronics. For
the Mag585 and Mag592 this noise is at 12.8kHz, which is well above the bandwidth of the
sensors. Where low noise operation is required, a filter should always be provided to reject
the noise which lies outside the band of interest.
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b. When the sensor output is digitized, it may be necessary to include an analogue, low-pass
anti-alias filter to prevent the creation of in-band noise by mixing the 12.8kHz excitation
frequency with the sampling clock frequency of the digitizer.
The level of unwanted breakthrough at 12.8kHz has been minimized in the Mag585 and
Mag592 but may still cause an apparently raised noise level when sampled at low sampling
frequencies without further analogue filtering.
c. In applications such as surveillance and magnetic signature monitoring it may be required
to remove both the DC standing field and all AC noise and pick-up above a set frequency. The
band of interest will be, say, 0.01 to 10Hz and a band pass filter can be used to provide the
required signal.
The Magmeter and PSU1 power supply units, which can be used with all sensors, contain
three low pass filters with a -3dB point at 10kHz together with three high pass filters with a
-3dB point at 0.1Hz.
The SCU1 signal conditioning unit provides filters with independent control of the low and
high pass filter sections, together with offset and gain control for the output of each axis.
6.5. Magnetic hysteresis
The Mag585 and Mag592 are designed to have an extremely low magnetic hysteresis. However,
Bartington Instruments recommends your magnetometer is not subjected to magnetic fields
greater than its stated measuring range for extended periods as this could alter the DC offset. If
this occurs, the offset will exhibit drift as it returns to its original offset specification.
Caution: Subjecting the magnetometer to fields in excess of 2 x the nominal range may
cause inaccuracy in future measurements. Degaussing the magnetometer can reverse
such an effect.
6.6. Environmental precautions
Refer to the product brochure for maximum environmental electrical and mechanical ratings.
Caution: Exceeding the maximum ratings may cause irreparable damage to your sensor.
7. Troubleshooting
The Mag585 and Mag592 are unlikely to suffer any defects in normal use. The most likely causes
of failure, and their solutions, are detailed in the following table:
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Cause of failure Solution
Power supply Check the power supply as detailed in Pre-Installation Tests.
Cables Check the cables as detailed in Pre-Installation Tests.
Power Input If no fault can be found in the power supply or cables, ensure
the cable length is not too long, causing excessive voltage drop
between the power supply and magnetometer. Refer to the
specifications defined in the product brochure.
Magnetometer In the event of any apparent malfunction, email service@
bartington.com or telephone the Bartington Instruments service
team on +44 (0)1993 706565. Attempted repair or opening of the
casing by users may invalidate the warranty.
A re-calibration service is available which is traceable to
international standards.
For information about disposal of the damaged unit, refer to End of
Life Disposal.
8. Care and maintenance
8.1. Cleaning the Mag585 and Mag592
Use water and mild soap to remove grime from external enclosures.
Caution: Never use chemicals, such as solvents, when cleaning the Mag585 and Mag592.
Caution: Take particular care when cleaning around electrical connections. Bent or
damaged pins may cause the magnetometer to malfunction.
8.2. Calibration
Return the Mag585 and Mag592 to Bartington Instruments for calibration at the recommended
intervals. Refer to the Calibration Certificate for further details.
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9. Storage and transport
Your sensor is a precision electronic instrument and should be treated as such.
Note: Avoid exposing this instrument to shocks or continuous vibration.
Note: Store only within the temperature range specified in the product brochure.
Note: Do not expose this instrument to strong magnetic fields while being stored.
10. End of life disposal
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.
10.1. Waste Electrical and Electronic Equipment (WEEE) Regulations
This sensor complies fully with Restriction of the Use of Certain Hazardous Substances in
Electrical and Electronic Equipment (RoHS) and WEEE Regulations current at the time of
printing.
Appendix 1: Use of Alternative Power Supplies
Bartington Instruments power supplies provide the most suitable methods for connecting to
and operating your sensor. If you have decided to use an alternative then the information in this
Appendix is important.
Caution: Failure to follow these instructions may result in incorrect sensor readings and in
some circumstances may cause irreparable damage to your sensor, power supply, or both.
Power supplies should normally provide ±12V. For the lowest noise applications, ripple in the
output should be in the mV region. The nominal current requirements are +45mA and -18mA
with an additional current in proportion to the measured field. The additional current is 1.4mA
per 100μT per axis and will be drawn from the positive or negative supply, depending on the
direction of the field.
The maximum output voltage swing from the sensor will always be less than the supply voltage.
In the temperature range -40°C to +70°C, and with an external load of 10kΩ, the maximum
output voltage will be less than each supply voltage by up to 2V. All parameters, other than the
output voltage range, remain unaffected for supply voltage changes in the range from ±8 to ±15V.
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The current drain is independent of the power supply voltage, and the unit will operate with
input voltages down to ±8V. As the output voltage swing is limited to 2V less than the supply
voltage, for a supply of ±8V the output will operate normally with any output between +6V and
-6V, representing a field of 0.6 of the full scale value in each direction. The scaling factor and
linearity will remain at the normal value up to this saturation point. The output will remain at
the saturation level if the field is increased beyond this point. Asymmetric supplies may be used,
provided that the minimum and maximum voltages are not exceeded for either polarity.
A1.1. Signal/power ground
The two signal/power ground conductors are connected to a common point within the sensor.
The power supply common (power 0V) should be connected to only one of them, which becomes
the power ground. The other conductor becomes the signal ground and is used as the 0V output
from the sensor. Each signal is then measured between the X, Y and Z output conductors and the
signal ground output. In this way, the signal ground carries no power supply currents.
The minimum current in the power ground conductor is approximately 25mA. On long cables,
this will give rise to an appreciable potential difference between the power supply end and
the sensor end of the power ground conductor. The use of separate power and signal ground
conductors will ensure that this voltage is not included in the voltage measured between the
signal outputs and the signal ground.
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A1.2. Recommended connection method
Figure 2. Ideal connection method.
Key to Figure 2:
1 Sensor 5 Signal Ground
2 Host 6 Power Ground
3 Host Power Supply 7 Ground
4 Host Local 0V
Figure 2 illustrates the recommended connection method for users who do not wish to use
Bartington Instruments’ power supplies.
Note: Using this method is essential when using cables over 10m.
The schematic shows signal and power grounds separated at the Host end. The Host is fitted
with buffer amplifiers configured as Instrumentation Amplifiers (IA), which have two high
impedance inputs, one connected to X, Y or Z and the other to signal ground. An IA produces an
output that is the voltage difference of its input referenced to a local 0V. This 0V reference may be
significantly different to either of the two input voltages to the IA (indicated by VCM in Figure 2).
Consult the manufacturer’s data for the part chosen, to ensure the common-mode range is not
exceeded.
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In this configuration there is a voltage drop due to the cable’s resistance along the power ground.
Typical current is 25mA and the resistance of a 100m, 24 AWG cable is 5Ω, resulting in a drop
of 0.125V. Thus the reference point for the X, Y and Z outputs is 0.125V difference to the Host
0V, which is the source of power for the sensor. However, no current flows in the signal ground
conductor because the IAs have very high input impedance and no voltage is dropped in the 5Ω
resistance of either signal ground or X, Y and Z conductors.
Connecting sensors using this method means that the sensor outputs are accurately read by the
IAs, which then refer them accurately back to the 0V of the Host equipment.
Bartington Instruments Limited
5, 10 & 11 Thorney Leys Business Park
Witney, Oxford, OX28 4GE, England
T: +44 (0)1993 706565
E: sales@bartington.com
F: +44 (0)1993 774813
The specifications of the products described in this brochure
are subject to change without prior notice. Bartington® is a
registered trademark of Bartington Instruments Ltd.
www.bartington.com
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