Bartington CU1 User manual

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INNOVATION IN MAGNETICS
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Bartington Instruments Ltd
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Operation Manual for
CU1 Helmholtz Coil System
Control Unit
OM3224/4

BARTINGTON INSTRUMENTS
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Table of Contents
1. About this Manual 3
1.1. Symbols Glossary 3
2. Safe Use 4
3. Introduction 4
4. CU1 Features 5
4.1. Front Panel 5
4.1.1. ON/OFF Power Switch with LED Indicator 5
4.1.2. Front Panel Connectors 5
4.2. Rear Panel 6
4.2.1. Rear Panel Connectors 6
5. Compatibility 6
6. CU1 Control Unit Installation 7
6.1. Test Assembly Location and Ventilation Requirements 7
6.2. CU1 Control Unit Connection to the PA1 Power Amplifier 7
6.2.1. Current Control Output 7
6.2.2. Current Monitor Input 7
6.3. Sensor Connection to CU1 Control Unit Device Under Test Input 7
6.4. Sensor Connection to CU1 Control Unit Auxiliary Input 8
6.5. CU1 Control Unit Connection to NI Acquisition Card 8
6.6. CU1 Control Unit Mains Power Supply 8
7. Powering Sequence 9
8. Troubleshooting, Care and Maintenance 9
9. Storage and Transport 9
10. Disposal 10
10.1. Waste Electrical and Electronic Equipment (WEEE) Regulations 10
Appendix A: Connecting the Components of the Helmholtz Coil System 11
Appendix B: Helmholtz Control Unit CU1 DAQ/PXI Connection 12
Appendix C: Guidance for Connection to Mains Supply 20

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1. About this Manual
This manual provides the information necessary to help customers install and operate the CU1
Control Unit. It is one component of the Bartington Instruments Helmholtz Coil System. This
manual should therefore be read in conjunction with:
• Compatible Helmholtz Coils Operation Manuals
• PA1 Control Power Amplifier Manual OM3225
• CU2 Closed-Loop Module (if applicable) OM3999
• Helmholtz Coil Control Software OM3596.
All manuals are available from the Helmholtz Coil System Operation Manual page. The relevant
products outline drawings can be found on the Helmholtz Coil System outline drawing page.
This manual should also be read in conjunction with the product brochure DS2613 which can
also be found on the product page.
Photographs of key components are included, labelled with numbers. A number in the text in
square brackets [ ] refers to that label.
Bartington Instruments cannot advise on the integration of this equipment with any third party
products.
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.
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.

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2. Safe Use
WARNING: The CU1 Control Unit is powered by mains electricity and contains uninsulated
parts. Ensure that the unit is properly earthed at all times. Ensure all local and national
codes on electrical installation and grounding are observed. Safety protection will be
impaired if the unit is used in a manner not specified in this manual.
WARNING: There are no customer serviceable components within this unit. The unit
should be opened by Bartington Instruments personnel only.
WARNING: This product is not qualified for use in explosive atmospheres or life support
systems. Consult Bartington Instruments for advice.
3. Introduction
The CU1 Control Unit constitute an interface unit between a Helmholtz Coil System and a
National Instruments-based control system. Signal corresponding to field generation are sent
to the PA1, whilst current monitor signals are return to the CU1. It also provides signal filtering
and power supply to one or two magnetometers connected to the Auxiliary and/or Device Under
Test inputs. Compatible NI cards can be directly connected to the back of the CU1 for ease of
interface.
The full Helmholtz Coil System consists of:
• HC1, HC2, HC9 or HC16 Helmholtz Coils: an assembly of up to three Helmholtz coils. See
related operation manuals. Ferronato Helmholtz Coils can also be operated through this
system.
• PA1 Power Amplifier. See OM3225.
• CU1 Control Unit: the control unit for the system which enables it to interface with a PC-
based test, measurement and control system.
• Optional CU2 Closed-Loop Module: allows active cancellation of external DC and AC
magnetic field disturbances using the CU2 Reference Magnetometer. See OM3999.
A diagram showing the connection of these separate items into one system is given in Appendix
A.
The CU1 can connect directly to a National Instruments acquisition card or PXI system to provide
a PC-based control system for the Helmholtz Coil System. A LabVIEW™-based Helmholtz Coil
Control Software is available from our website, and is designed to operate when the system is
running from a NI card, with the CU1 and PA1.

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4. CU1 Features
4.1. Front Panel
Figure 1. Front view of CU1 Control Unit.
Key
1. Current Control Output 4. Current Monitor Input
2. Auxiliary Input 5. ON/OFF power switch with LED indicator
3. Device Test Input
4.1.1. ON/OFF Power Switch with LED Indicator
The ON/OFF power switch [5] controls AC mains power to the CU1 Control Unit.
The LED indicator has two colour states (red or green) and is controlled by the user software.
4.1.2. Front Panel Connectors
Inputs
Auxiliary Input [2]: this is a single ended or differential input, which can be that of a three-axis
magnetic field sensor.
Device Test Input [3]: this is a single ended or differential input for a three-axis magnetic field
sensor to be tested. This sensor is also termed the Device Under Test (DUT).
Current Monitor Input [4]: this is a differential input for monitoring the current in the Helmholtz
Coil. This should be connected to the Current Monitor Output of the PA1 Power Amplifier.
Auxiliary and DUT inputs are provided with a switchable, analogue, anti-aliasing filter which can
be enabled via a National Instruments acquisition card connected to the CU1.
Details of the pin-outs are available in DR3320.
Outputs
Current Control Output [1]: this provides three differential analogue outputs to the PA1 Power
Amplifier which control the power to be applied to the Helmholtz Coil in order to generate and
regulate the required DC or AC magnetic field.
Details of the pin-outs are available on DR3320.
1 2 3 4 5

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4.2. Rear Panel
Figure 2. Rear view of CU1 Control Unit
Key
6. Mains input IEC socket 8. Connector 1
7. Earth terminal post 9. Connector 0
4.2.1. Rear Panel Connectors
Mains Input IEC Socket [6]: this is for connection of an IEC lead. See datasheet DS2613 for
supply voltage.
Earth terminal post [7]: if an appropriate earth/ground connection is not provided through the
mains supply lead, connect this terminal post to the National Instruments system chassis earth
terminal, the instrument rack earth, or a permanent earth ground.
Connector 0 [8]: this is a National Instruments system interface socket for connection to the
National Instruments system DAQ module.
Connector 1 [9]: as Connector 0.
5. Compatibility
The CU1 Control Unit is compatible with Bartington Instruments PA1 for use in Bartington
Helmholtz Coil System. The CU1 is also compatible for use with the CU2 Closed-Loop Module.
A range of National Instruments card can directly connect to the CU1. A non-exhaustive list of
compatible card is included here:
• NI-PXI-6289 Card + compatible Chassis and Controller and connection cables
• NI-PCIe-6353 + connection cables
• NI-USB-6363 + connection cables
6789

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6. CU1 Control Unit Installation
6.1. Test Assembly Location and Ventilation Requirements
The CU1 has no forced ventilation requirements and can be sited typically on top of the PA1. The
CU1 and PA1 should be located at least 3m from the Helmholtz Coils to avoid interferences.
Note: For optimum results, the ambient temperature should not exceed the maximum
specified in the data sheet.
6.2. CU1 Control Unit Connection to the PA1 Power Amplifier
6.2.1. Current Control Output
Connect the CU1 Current Control Output [1] to the PA1 Current Control Input using the cable
provided. Labels on the cable identify each end of the cable.
6.2.2. Current Monitor Input
Connect the Current Monitor Input [4] to the PA1 Current Monitor Output using the cable
provided. Labels on the cable identify each end of the cable.
The Current Monitor signal is sent to the National Instruments card for digitisation and is
available in the Helmholtz Coil Control Software.
6.3. Sensor Connection to CU1 Control Unit Device Under Test Input
Both single-ended and differential output sensors can be connected to the Device Under Test
input. The supply voltage to the sensor can be set by the user. Both the selection of the sensor
output type and the supply voltage can be set through the software and is controlled via one of
the digital I/O line on the National Instruments card.
The Device Under Test output is sent to the National Instruments card for digitisation and is
available in the Helmholtz Coil Control Software.
Refer to the datasheet DS2613 for details of the supply voltage limits, and the analogue input
range.
Ensure to not apply a supply voltage exceeding the connected sensor’s rating.
An extension cable to connect to the sensor’s cable to the CU1 Device Under Test port is supplied
with the CU1. This is to be used in case the sensor cable is not long enough.
Note: Bartington Instruments can supply suitable cables for all Bartington Instruments
compatible magnetic field sensors.

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6.4. Sensor Connection to CU1 Control Unit Auxiliary Input
Both single-ended and differential output sensors can be connected to the Auxiliary input. The
selection of the sensor output type is set through the software and is controlled via one of the
digital I/O line on the National Instruments card. The supply voltage to the sensor is set to ±15V
and cannot be changed by the user.
The Auxiliary output signal is sent to the National Instruments card for digitisation and is
available in the Helmholtz Coil Control Software.
Refer to the datasheet DS2613 for details of the supply voltage limits, and the analogue input
range.
Ensure to not apply a supply voltage exceeding the connected sensor’s rating.
Self-resetting semiconductor fuses limit the current to each Auxiliary power rail output,
protecting the connected sensor. The fuses can be reset by switching off the unit and allowing it
to cool for a few minutes.
Note: Bartington Instruments can supply suitable cables for all Bartington Instruments
compatible magnetic field sensors.
6.5. CU1 Control Unit Connection to NI Acquisition Card
The CU1 Control Unit can be connected to a National Instruments interface cards using two
shielded cables manufactured by National Instruments (SHC68-68-EPM cables). Details of the
pin-out of the CU1 to the acquisition card can be found in Appendix B.
The CU1 will emit a beep when connection to a National Instruments acquisition card and PC is
not detected. The beep will also sound at powering up until the Helmholtz Coil Control Software
is started.
6.6. CU1 Control Unit Mains Power Supply
Details of suitable power supply for the CU1 Control Unit are provided in the product brochure,
with the supply beeing earthed/grounded. The supply from a standard wall outlet should be
suitable in most countries. A compatible mains cable supplied with a UK 13A plug, an EU plug or
bare ends can be specified at the time of ordering. In the latter case, refer to Appendix C.
A slow blow fuse is fitted internally, to limit the mains supply current to the power supply
modules.
Caution: If the power supply fuse has blown, this indicates a faulty unit. Please contact
Bartington Instruments on [phone].

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7. Powering Sequence
Before powering the system, you should ensure that all the connections between the Helmholtz
Coil and the PA1, the PA1 and the CU1 and/or CU2 as well as the CU1 to a suitable National
Instruments acquisition card (or PXI-system) are done.
Once all connections are done, the following sequence should be used:
• Power the PC and National Instruments acquisition card or PXI system
• If using a CU2, ensure that the CU2 Reference Magnetometer is connected to the CU2 Module
• Power the CU1
• Power the PA1
To power down the system, the reverse sequence should be followed.
Please note that the equipment should be left to warm up for at least 12 hours before any of the
calibration is undertaken.
8. Troubleshooting, Care and Maintenance
In the event of any apparent malfunction, please email [e-mail], or telephone
the Bartington Instruments service team on [phone].
Note: Fault finding by customers may invalidate the warranty.
9. Storage and Transport
The CU1 Control Unit should be handled with care.
Bartington Instruments has supplied this product in appropriate packaging for transporting it
safely. This packaging should be used for any future transport.
Refer to datasheet DS2613 for this product’s maximum environmental, electrical and mechanical
ratings.
Caution: Exceeding the maximum environmental ratings may cause irreparable damage to
the equipment.

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10. Disposal
This product should not be disposed of in domestic or municipal waste. For information about
disposing of this product safely, check local regulations for disposal of electrical / electronic
products.
10.1. Waste Electrical and Electronic Equipment (WEEE) Regulations
This product 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
writing.