Bartington Mag646 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.
Operation Manual for
Mag646
Single Axis Unpackaged Magnetic Field Sensor
OM3836/2

BARTINGTON INSTRUMENTS
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Table of Contents
1. About this Manual 3
1.1. Symbols Glossary 3
2. Safe Use 3
3. Introduction 4
4. General Description 4
5. Connections 4
5.1. Cable Recommendations 4
5.2. Connection to Power Supply/Acquisition Unit 5
6. Using the Mag646 5
6.1. Mag646 Operation 5
6.2. Electromagnetic Compatibility 6
7. Troubleshooting 6
8. Care and Maintenance 7
8.1. Calibration 7
9. End of Life Disposal 7

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1. About this Manual
This manual provides the information necessary to help Mag646 customers connect, install and
operate, the Mag646 magnetic field sensor.
Technical specifications of the products, including power supply requirements and analogue
output details, can be found in DS3836, while outline drawings of sensor head, electronics board
and cable can be found on the Mag646 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
The Mag646 is an unpackaged single-axis fluxgate sensor that provides highly linear magnetic
response and low hysteresis. The sensor consists of a single, feedback-stabilised, fluxgate
sensing element arranged along one of two directions, in line with the PCB or perpendicular to
the long side of the PCB.
The sensor has no power supply or data processing abilities of its own and must always be
connected to a power supply to be able to function.
Regulating the power supply internally ensures that the Mag646 is suitable for battery-powered
operation, over both long and short cables.
4. General Description
Figure 1. Mag646 sensor
Key:
1. PCB header 2. Sensing Element
3. Mounting Holes
5. Connections
5.1. Cable Recommendations
The Mag646 electronics board provides unbalanced 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 your own cable, the following recommendations should be followed:
2
3
1
3
3
3

BARTINGTON INSTRUMENTS
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• 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).
• The connecting cable to the sensor should be a five-core screened cable. Two cores will
be used for positive and negative power supply lines, one core for output signal, one
core for signal common, and one for power supply ground.
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 DS3836.
Caution: Connect the Mag646 electronics board 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 DR2945.
Where no Bartington power supply or acquisition unit is used, some basic recommendations for
integration of the sensor are available in AN0042.
6. Using the Mag646
6.1. Mag646 Operation
Once the electronics is fully connected to both sensor head and power supply/acquisition unit,
the supply can be switched on. The sensor will provide an analogue output which is proportional
to the field measured. Please refer to DS3836 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 Mag646 sensors are not shielded for immunity from, or emission of,
electromagnetic fields.
Note: The Mag646 sensors are intended for integration into other systems. Ensure these
meet the appropriate level of shielding.
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 is no
analogue
output present
in Z
Sensor head not
connected
Ensure that the sensor head and electronics are
connected as per “Cable Recommendations”.
Power supply
not connected or
not sufficient to
power the sensor
Check that the power supply meets the requirement
provided in DS3836 and that the connection is as per
“Connection to Power Supply/Acquisition Unit”.
Broken coil If the axis is not responding, the fluxgate coil could be
damaged. Please return the unit to us for assessment.
Component
damage
If the axis is 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.

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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 if applicable.
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 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 Mag646 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 Mag646 electronics board, to prevent irreparable
damage.
The Mag646 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 Mag646 to Bartington Instruments for calibration at the recommended intervals.
Refer to the Calibration Certificate for further details.
9. End of Life Disposal
This product (electrical and electronic equipment) should not be placed in municipal waste.
Check local regulations for disposal of 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.