Bartington Mag648 User manual

www.bartington.com
INNOVATION IN MAGNETICS
Telephone: [phone] •Email: [email protected] •Website: www.bartington.com
Bartington Instruments Ltd
5, 8, 10, 11 & 12 Thorney Leys Business Park
Witney, Oxford, OX28 4GE. England
®The copyright of this document is the property of Bartington Instruments Ltd.
Bartington is a registered trademark of Bartington Instruments Limited in the following countries: Australia, Brazil, Canada, China, European Union, India,
Israel, Japan, Mexico, New Zealand, Norway, Russia, Singapore, South Korea, Switzerland, Turkey, United Kingdom, United States of America and Vietnam.
OM2298/4
Operation Manual for
Mag648 and Mag649™
Low Power Three-Axis Magnetic Field Sensors

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Table of Contents
1. About this Manual 3
1.1. Symbols Glossary 3
2. Safe Use 3
3. Introduction to the Mag648 & Mag649™ Series 4
4. General Description 4
4.1. Vector Measurements and Conventions 4
5. Connections 5
5.1. Cable Recommendations 5
5.2. Connection to Power Supply/Acquisition Unit 5
5.4. Mounting Recommendations 6
6. Using the Mag648 and Mag649™ 6
6.1. Mag648 and Mag649™ Operation 6
6.2. Electromagnetic Compatibility 7
7. Troubleshooting 7
8. Care and Maintenance 8
8.1. Calibration 8
9. End of Life Disposal 8

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1. About this Manual
This manual provides the information necessary to help customers connect, install and operate,
the Mag648 and Mag649™ magnetic field sensors.
Technical specifications of the products, including power supply requirements and analogue
output details, can be found in DS2298, whilst outline drawings of both sensor head, electronics
board and cable can be found on the Mag648/Mag649 product page.
1.1. Symbols Glossary
The following symbols used within this manual call your attention to specific types of
information:
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.
Indicates a situation in which ESD protection should be used.
Identifies items that must be disposed of safely to prevent unnecessary damage to the
environment.
Note: A paragraph in this format provides useful supporting information on how to make
better use of your purchase.
2. Safe Use
WARNING: These products are not qualified for use in explosive atmospheres or life
support systems. Consult Bartington Instruments for advice.
WARNING: Environmental and electrical specifications should not be exceeded.
To prevent irreparable damage, electrostatic discharge (ESD) protection and precautions
must be used when handling the unpackaged sensor electronics board.
Note: Do not expose to strong magnetic fields while being stored as this can magnetise
the sensor and affect its offset performance.

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3. Introduction
Both the Mag648 and Mag649™ are magnetometers consisting of a cluster 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 crosstalk between axes. These
characteristics, combined with the compact design and very low power consumption, make
these magnetometers ideally suited for perimeter surveillance within a multi-sensor network.
Regulating the power supply internally ensures the Mag64x series is suitable for battery powered
operation, over both long and short cables.
The Mag649™ offers a wider bandwidth than the standard Mag648.
High stability circuitry ensures that a minimum of ten years’ service should be expected.
4. General Description
Key:
1. Connector cable 2. Sensing Elements
3. Mounting Holes
4.1. Vector Measurements and Conventions
Each magnetometer 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 (see 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.
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.
2
3
1

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North
+X
Thumb
Down
+Z
2nd Finger
East
+Y
1st Finger
5. Connections
5.1. Cable Recommendations
The Mag648 and Mag649™ electronics board provides balanced output lines for analogue signal
transmission. Suitable shielded cables can be supplied.
Cables are particularly prone to wear and damage if twisted, flexed beyond their design limits, or
subjected to excessive or repeated movement. All cables should be mounted securely in place.
When designing their own cable, the following recommendation should be followed:
• ensure that the cables are shielded to prevent them picking up electromagnetic
interference.
• the cable shield should be connected to power supply ground at the power supply end
(either through the connector body, or by connecting the shield to the power ground
wire).
5.2. Connection to Power Supply/Acquisition Unit
Caution: When providing your own power supply, do not exceed the voltage rating, provide
sufficient current, and ensure correct polarity is respected see DS2298.
Figure 1. The ‘right hand’ rule.

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Caution: Connect the Mag648/Mag649™ sensor before the supply is energized, as this
prevents high surge currents which could cause damage.
Note: Apply the positive and negative supplies simultaneously, and avoid leaving the
electronics board connected to one polarity only.
The analogue output of the sensors as well as the power supply connectors are available on the
outline drawing DR2389.
Where no Bartington power supply or acquisition unit is used, some basic recommendation for
integration of the sensor are available in AN0042.
5.3. Mounting Recommendations
Each magnetometer has a set of mounting holes to allow attachment to a stable base or fixture.
Refer to the mechanical drawings on the product page.
Caution: (For the Mag648S and Mag649S only) Take care to align the cable to the connector
correctly, to avoid damage to the connector or magnetometer. When aligned correctly,
hand tighten the connector. Refer to the product brochure for detailed information.
Caution: (For the Mag648U and Mag649U only) Allow for recess above the coil blocks when
mounting the sensor. Mounting screws may protrude on top.
Note: Other versions of the Mag648 and Mag649™ have plug-in type connectors.
The sensor can also mounted on the Bartington Instruments Mag-TA Universal Tripod Adaptor.
See drawing DR3140, available from Bartington Instruments, for instructions on how to do this.
6. Using the Mag648 and Mag649™
6.1. Mag648 and Mag649™ Operation
The sensor will provide an analogue output which is proportional to the field measured. Please
refer to DS2298 for the sensor’s scaling factor.
Testing of the sensor’s response can be done, as an example, by moving the sensor in the Earth’s
field and ensuring that the signal varies in relation to orientation. In the horizontal plane, a
minimum value is obtained when the axis is in the magnetic East-West direction, and maximum
when pointing Magnetic North.

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6.2. Electromagnetic Compatibility
Note: The Mag648 and Mag649™ sensors are not shielded for immunity from, or emission
of, electromagnetic fields.
7. Troubleshooting
The sensor is unlikely to suffer any defects in normal use: no internal components are
serviceable. The most likely causes of failure, and their solutions, are detailed in the following
table.
In the event of any apparent malfunction beyond those described in the table below, please email
[email protected]om, or telephone the Bartington Instruments service team on +44 (0)1993
706565.
Problem Cause Solution
There are
no analogue
outputs
present in X, Y
or Z
Sensor head not
connected
Ensure that the sensor head and electronics are
connected as per Probe and Electronics wiring.
Power supply
not connected or
not sufficient to
power the sensor
Check that the power supply meets the requirement
provided in DS2298 and that the connection is as per
Connection to Power Supply/Acquisition Unit.
Broken coil If only one or two axes is (are) not responding, one of the
fluxgate coil could be damaged. Please return the unit to
us for assessment.
Component
damage
If only one or two axes is (are) not responding, one
component could be damaged. Please return the unit to
us for assessment.
There is an
abnormal
current draw
on the sensor
Faulty
component
A faulty component can lead to an abnormal current
draw before it fails. Please return the unit to us for
assessment.
The
amplitude of
the Earth’s
field is
abnormal
Erroneous
scaling factor
If the scaling factor applied to convert volts into
field amplitude is erroneous, the field reading will
appear either systematically high or low depending
on the error on the scaling factor. Please check the
conversion rate used in the acquisition software.

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The noise on
the output
is much
higher than
the specified
noise at low
frequency
Ambient
environment is
noisy
A noisy environment will be picked up by the sensor.
Noise tests should be carried out in a shielded
environment.
Sensor
breakthrough
not filtered
properly
The sensor has a high frequency noise component
referred to as breakthrough in the datasheet. This
signal at the excitation frequency of the sensor, if
unfiltered can be aliased creating an apparent low
frequency noise. Check that a suitable low pass filter
is used or that the signal is sampled at a suitable
frequency (at least twice the breakthrough frequency).
8. Care and Maintenance
Surface dirt contamination on the Mag648 and Mag649™ probe should be removed using
a mild detergent solution only. Electronics should be cleaned with an antistatic cloth only.
ESD protection should be used when handling the electronics board, to prevent irreparable
damage.
The Mag648 and Mag649™ electronics board should be treated subject to ESD precautions.
Note: Store only within the temperature range specified in the product brochure.
Note: Do not expose to strong magnetic fields while being stored as this can magnetise
the sensor and affect its offset performance.
8.1. Calibration
Return the Mag648 or Mag649™ to Bartington Instruments for calibration at the recommended
intervals. Refer to the Calibration Certificate for further details.
9. 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.

www.bartington.com
INNOVATION IN MAGNETICS
Telephone: [phone] •Email: [email protected] •Website: www.bartington.com
Bartington Instruments Ltd
5, 8, 10, 11 & 12 Thorney Leys Business Park
Witney, Oxford, OX28 4GE. England
®The copyright of this document is the property of Bartington Instruments Ltd.
Bartington is a registered trademark of Bartington Instruments Limited in the following countries: Australia, Brazil, Canada, China, European Union, India,
Israel, Japan, Mexico, New Zealand, Norway, Russia, Singapore, South Korea, Switzerland, Turkey, United Kingdom, United States of America and Vietnam.