Ametek 7124 User manual

Model 7124
Precision
Lock-in Amplifier
Instruction Manual
197776-A-MNL-F
Copyright © 2017 AMETEK ADVANCED MEASUREMENT TECHNOLOGY, INC

Firmware Version
The instructions in this manual apply to operation of a Model 7124 Precision Lock-in Amplifier that is fitted
with Version 2.20 or later operating firmware. Users of instruments that are fitted with earlier firmware
versions can update them to the current version free of charge by downloading an Update Pack from our
website at www.signalrecovery.com The pack includes full instructions for use.
Trademarks
AMETEK® and the b® and alogos are registered trademarks of AMETEK, Inc
Other product and company names mentioned are trademarks or trade names of their respective
companies.
Company Names
SIGNAL RECOVERY is part of Advanced Measurement Technology, Inc, a division of AMETEK, Inc. It
includes the businesses formerly trading as EG&G Princeton Applied Research, EG&G Instruments
(Signal Recovery), EG&G Signal Recovery and PerkinElmer Instruments (Signal Recovery).

Table of Contents Table of Contents
i
General Safety Precautions..............................................................................................................vii
Chapter One, Introduction
1.1 How to Use This Manual.................................................................................................................................. 1-1
1.2 What is a Lock-in Amplifier?........................................................................................................................... 1-2
1.3 Key Specifications and Benefits ...................................................................................................................... 1-3
Chapter Two, Installation and Initial Checks
2.1 Installation........................................................................................................................................................ 2-1
2.1.01 Introduction ............................................................................................................................................. 2-1
2.1.02 Rack Mounting........................................................................................................................................ 2-1
2.1.03 Inspection ................................................................................................................................................ 2-1
2.1.04 Line Cord Plugs....................................................................................................................................... 2-1
2.1.05 Line Voltage Selection and Line Fuses................................................................................................... 2-1
2.2 Initial Checks.................................................................................................................................................... 2-3
2.2.01 Introduction ............................................................................................................................................. 2-3
2.2.02 Procedure................................................................................................................................................. 2-3
2.3 Line Frequency Filter Adjustment ................................................................................................................... 2-7
2.3.01 Introduction ............................................................................................................................................. 2-7
2.3.02 Procedure................................................................................................................................................. 2-7
Chapter Three, Technical Description
3.1 Introduction ...................................................................................................................................................... 3-1
3.2 Operating Modes.............................................................................................................................................. 3-1
3.2.01 Introduction ............................................................................................................................................. 3-1
3.2.02 Single Reference / Dual Reference ......................................................................................................... 3-1
3.2.03 Tandem Demodulation............................................................................................................................ 3-1
3.2.04 Single Harmonic / Dual Harmonic.......................................................................................................... 3-2
3.2.05 Internal / External Reference Mode ........................................................................................................ 3-2
3.2.06 Virtual Reference Mode.......................................................................................................................... 3-2
3.3 Principles of Operation..................................................................................................................................... 3-2
3.3.01 Block Diagram......................................................................................................................................... 3-2
3.3.02 Signal Channel Inputs - 7124 RCU......................................................................................................... 3-4
3.3.03 Line Frequency Rejection Filter.............................................................................................................. 3-5
3.3.04 AC Gain and Dynamic Reserve............................................................................................................... 3-5
3.3.05 Anti-Aliasing Filter ................................................................................................................................. 3-6
3.3.06 Analog Fiber Links.................................................................................................................................. 3-7
3.3.07 Auxiliary Signal Input - Main Console................................................................................................... 3-7
3.3.08 Main Analog-to-Digital Converter.......................................................................................................... 3-8
3.3.09 Reference Channel Inputs - 7124 RCU................................................................................................... 3-8
3.3.10 Reference Channel Inputs- Main Console............................................................................................... 3-8
3.3.11 Reference Channel .................................................................................................................................. 3-8
3.3.12 Phase-Shifter ........................................................................................................................................... 3-9

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3.3.13 Internal Oscillator - General...................................................................................................................3-10
3.3.14 Internal Oscillator - Update Rate ...........................................................................................................3-10
3.3.15 Internal Oscillator - Frequency & Amplitude Sweeps...........................................................................3-10
3.3.16 Internal Oscillator - Voltage Control .....................................................................................................3-11
3.3.17 Demodulators - Dual Phase Multipliers.................................................................................................3-11
3.3.18 Demodulators - Output Filters................................................................................................................3-11
3.3.19 Fast Curve Buffer...................................................................................................................................3-12
3.3.20 Main Output Processor - General...........................................................................................................3-12
3.3.21 Main Output Processor - Output Offset and Expand.............................................................................3-12
3.3.22 Main Output Processor - Vector Magnitude and Phase.........................................................................3-13
3.3.23 Main Output Processor - Noise Measurements......................................................................................3-14
3.3.24 Main Output Processor - Standard Curve Buffer...................................................................................3-15
3.3.25 Analog Outputs (DACs).........................................................................................................................3-15
3.3.26 Auxiliary Analog Inputs (ADCs)...........................................................................................................3-15
3.3.27 Main Microprocessor - General.............................................................................................................3-16
3.3.28 Main Microprocessor - Spectral Display ...............................................................................................3-16
3.3.29 Main Microprocessor - Auto Functions.................................................................................................3-16
3.3.30 Main Microprocessor - User Settings ....................................................................................................3-18
3.4 General............................................................................................................................................................3-18
3.4.01 Accuracy.................................................................................................................................................3-18
3.4.02 Power-up Defaults..................................................................................................................................3-18
Chapter Four, Front and Rear Panels
4.1 Front Panel - Main Console ..............................................................................................................................4-1
4.1.01 AUX Signal Input Connector...................................................................................................................4-1
4.1.02 MON Connector.......................................................................................................................................4-1
4.1.03 REF IN Connector....................................................................................................................................4-1
4.1.04 OSC OUT Connector ...............................................................................................................................4-2
4.1.05 LCD Screen..............................................................................................................................................4-2
4.1.06 HELP Key................................................................................................................................................4-5
4.1.07 MENU Key ..............................................................................................................................................4-5
4.1.08 SELECT CONTROL Key........................................................................................................................4-5
4.2 Rear Panel - Main Console................................................................................................................................4-6
4.2.01 Line Power Switch...................................................................................................................................4-6
4.2.02 Line Power Input Assembly.....................................................................................................................4-6
4.2.03 DIGITAL I/O Connector..........................................................................................................................4-6
4.2.04 USB Connector ........................................................................................................................................4-6
4.2.05 LAN Connector........................................................................................................................................4-7
4.2.06 RS232 Connector .....................................................................................................................................4-7
4.2.07 AUX RS232 Connector............................................................................................................................4-7
4.2.08 PRE-AMP POWER Connector................................................................................................................4-7
4.2.09 ADC TRIG IN Connector ........................................................................................................................4-7
4.2.10 ADC 1, ADC 2, ADC 3 and ADC 4 Connectors .....................................................................................4-7
4.2.11 REF MON Connector...............................................................................................................................4-7
4.2.12 TTL REF IN Connector ...........................................................................................................................4-7
4.2.13 TRIG IN Connector..................................................................................................................................4-8
4.2.14 TRIG OUT Connector..............................................................................................................................4-8
4.2.15 DAC 1, DAC 2, DAC 3, and DAC 2 Connectors ....................................................................................4-8
4.2.16 FIBER LINKS Connectors.......................................................................................................................4-8
4.3 Front Panel - 7124 RCU....................................................................................................................................4-8

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4.3.01 A and B/I Signal Input Connectors ......................................................................................................... 4-8
4.3.02 REF IN Connector................................................................................................................................... 4-9
4.3.03 OSC OUT Connector .............................................................................................................................. 4-9
4.3.04 STATUS LED......................................................................................................................................... 4-9
4.4 Rear Panel - 7124 RCU.................................................................................................................................... 4-9
4.4.01 Line Power Switch .................................................................................................................................. 4-9
4.4.02 Line Power Input Assembly.................................................................................................................... 4-9
4.4.03 DIGITAL OUTPUT Connector............................................................................................................... 4-9
4.4.04 TTL REF IN Connector......................................................................................................................... 4-10
4.4.05 POWER IN/OUT Connector................................................................................................................. 4-10
4.4.06 CONTROL, REF OUT, OSC IN, and SIG OUT Fiber Optic Connectors............................................ 4-10
4.4.07 SIG MON Connector............................................................................................................................. 4-10
Chapter Five, Front Panel Operation
5.1 Introduction ...................................................................................................................................................... 5-1
5.2 Menu Structure................................................................................................................................................. 5-2
5.3 Menu Descriptions - Single Reference Mode .................................................................................................. 5-3
5.3.01 Main Display........................................................................................................................................... 5-3
5.3.02 Control Selection Menu .......................................................................................................................... 5-5
5.3.03 Main Menu 1 ........................................................................................................................................... 5-7
5.3.04 Signal Channel Menu 1........................................................................................................................... 5-7
5.3.05 Reference Channel Menu...................................................................................................................... 5-11
5.3.06 Output Filters Menu .............................................................................................................................. 5-13
5.3.07 Output Offset & Expand Menu ............................................................................................................. 5-14
5.3.08 Output Equations Menu......................................................................................................................... 5-15
5.3.09 Oscillator Menu..................................................................................................................................... 5-16
5.3.10 Frequency Sweep Menu........................................................................................................................ 5-18
5.3.11 Amplitude Sweep Menu........................................................................................................................ 5-21
5.3.12 Amplitude Modulation Menu................................................................................................................ 5-23
5.3.13 Frequency Modulation (VCO) Menu.................................................................................................... 5-24
5.3.14 Auto Functions Menu............................................................................................................................ 5-25
5.3.15 Configuration Menu .............................................................................................................................. 5-27
5.3.16 Communications Menu ......................................................................................................................... 5-29
5.3.17 RS232 Settings Menu............................................................................................................................ 5-30
5.3.18 Ethernet Settings Menu......................................................................................................................... 5-32
5.3.19 USB Status Menu.................................................................................................................................. 5-34
5.3.20 Communications Monitor...................................................................................................................... 5-35
5.3.21 Options Menu........................................................................................................................................ 5-35
5.3.22 Configuration Menu 2 ........................................................................................................................... 5-36
5.3.23 Spectral Display .................................................................................................................................... 5-37
5.3.24 Main Menu 2 ......................................................................................................................................... 5-39
5.3.25 Curve Buffer Menu ............................................................................................................................... 5-41
5.3.26 Curve Trigger Menu.............................................................................................................................. 5-42
5.3.27 Curve Select Menu................................................................................................................................ 5-44
5.3.28 Single Graph Menu ............................................................................................................................... 5-46
5.3.29 Double Graph Menu.............................................................................................................................. 5-47
5.3.30 User Settings Menu ............................................................................................................................... 5-48
5.3.31 ADC Menu ............................................................................................................................................ 5-49
5.3.32 DAC Menu ............................................................................................................................................ 5-51

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5.3.33 Digital Port Menu...................................................................................................................................5-55
5.3.34 RCU Digital Port Menu..........................................................................................................................5-56
5.3.35 Fiber Calibration Menu..........................................................................................................................5-56
5.4 Menu Descriptions - Virtual Reference Mode................................................................................................5-57
5.4.01 Virtual Reference Menus .......................................................................................................................5-57
5.4.02 Virtual Reference Main Display ............................................................................................................5-60
5.4.03 Virtual Reference Configuration Menu .................................................................................................5-61
5.5 Menu Descriptions - Dual Reference Mode....................................................................................................5-61
5.5.01 Dual Reference Setup Menu ..................................................................................................................5-61
5.5.02 Dual Reference Main Display................................................................................................................5-62
5.5.03 Dual Reference Channel Menu..............................................................................................................5-66
5.5.04 Dual Reference Channel Menu 2...........................................................................................................5-68
5.5.05 Dual Reference Output Filters Menu 1..................................................................................................5-68
5.5.06 Dual Reference Output Filters Menu 2..................................................................................................5-70
5.5.07 Dual Reference Output Offset Ref 1 Menu............................................................................................5-70
5.5.08 Dual Reference Output Offset Ref 2 Menu............................................................................................5-72
5.5.09 Dual Reference Auto Functions Menus.................................................................................................5-73
5.5.10 Dual Reference Configuration Menu.....................................................................................................5-74
5.5.11 Dual Reference and Dual Harmonic Modes Curve Select Menu ..........................................................5-74
5.5.12 Dual Reference and Dual Harmonic Modes DAC Menu.......................................................................5-75
5.6 Menu Descriptions - Dual Harmonic Mode....................................................................................................5-79
5.6.01 Dual Harmonic Setup Menu...................................................................................................................5-79
5.6.02 Dual Harmonic Main Display................................................................................................................5-80
5.6.03 Dual Harmonic Reference Channel Menu.............................................................................................5-84
5.6.04 Dual Harmonic Output Filters Menu .....................................................................................................5-86
5.6.05 Dual Harmonic Output Filters Menu 2 ..................................................................................................5-87
5.6.06 Dual Harmonic Output Offset Harm 1 Menu.........................................................................................5-88
5.6.07 Dual Harmonic Output Offset Harm 2 Menu.........................................................................................5-89
5.6.08 Dual Harmonic Auto Functions Menus .................................................................................................5-90
5.6.09 Dual Harmonic Configuration Menu .....................................................................................................5-91
5.7 Typical Lock-in Amplifier Experiment...........................................................................................................5-91
Chapter Six, Computer Operation
6.1 Introduction.......................................................................................................................................................6-1
6.2 Capabilities........................................................................................................................................................6-1
6.2.01 General.....................................................................................................................................................6-1
6.2.02 Operation..................................................................................................................................................6-1
6.2.03 Communications Monitor Menu..............................................................................................................6-1
6.2.04 Compound Commands.............................................................................................................................6-1
6.3 RS232 Operation...............................................................................................................................................6-1
6.3.01 Introduction..............................................................................................................................................6-1
6.3.02 General Features.......................................................................................................................................6-2
6.3.03 Choice of Baud Rate ................................................................................................................................6-2
6.3.04 Choice of Number of Data Bits................................................................................................................6-2
6.3.05 Choice of Parity Check Option ................................................................................................................6-3
6.3.06 Auxiliary RS232 Interface .......................................................................................................................6-3
6.3.07 Handshaking and Echoes .........................................................................................................................6-3
6.3.08 Terminators ..............................................................................................................................................6-4
6.3.09 Delimiters.................................................................................................................................................6-4
6.3.10 Status Byte, Prompts and Overload Byte.................................................................................................6-4

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v
6.4 USB Operation ................................................................................................................................................. 6-5
6.4.01 Introduction ............................................................................................................................................. 6-5
6.4.02 General Features...................................................................................................................................... 6-5
6.4.03 Terminator, Status Byte, and Overload Byte .......................................................................................... 6-5
6.4.04 Delimiters................................................................................................................................................ 6-6
6.5 Ethernet Operation ........................................................................................................................................... 6-7
6.5.01 Introduction ............................................................................................................................................. 6-7
6.5.02 IP Address ............................................................................................................................................... 6-7
6.5.03 Home Page............................................................................................................................................... 6-7
6.5.04 Sockets..................................................................................................................................................... 6-8
6.5.05 Terminator, Status Byte, and Overload Byte .......................................................................................... 6-8
6.5.06 Delimiters................................................................................................................................................ 6-9
6.6 Command Format............................................................................................................................................. 6-9
6.7 Command Descriptions .................................................................................................................................. 6-10
6.7.01 Signal Channel ...................................................................................................................................... 6-10
6.7.02 Reference Channel ................................................................................................................................ 6-12
6.7.03 Signal Channel Output Filters............................................................................................................... 6-14
6.7.04 Signal Channel Output Amplifiers........................................................................................................ 6-15
6.7.05 Instrument Outputs................................................................................................................................ 6-17
6.7.06 Internal Oscillator.................................................................................................................................. 6-19
6.7.07 Analog Outputs...................................................................................................................................... 6-23
6.7.08 Digital I/O.............................................................................................................................................. 6-24
6.7.09 Auxiliary Inputs..................................................................................................................................... 6-24
6.7.10 Output Data Curve Buffer..................................................................................................................... 6-25
6.7.11 Computer Interfaces .............................................................................................................................. 6-32
6.7.12 Instrument Identification....................................................................................................................... 6-34
6.7.13 Front Panel ............................................................................................................................................ 6-34
6.7.14 Auto Default and Calibration................................................................................................................ 6-34
6.7.15 Dual Mode Commands.......................................................................................................................... 6-35
6.5 Programming Examples ................................................................................................................................. 6-36
6.5.01 Introduction ........................................................................................................................................... 6-36
6.5.02 Basic Signal Recovery........................................................................................................................... 6-36
6.5.03 Frequency Response Measurement....................................................................................................... 6-36
6.5.04 X and Y Output Curve Storage Measurement....................................................................................... 6-37
Appendix A, Specifications
Appendix B, Pinouts
B1 RS232 Connector Pinout .................................................................................................................................B-1
B2 Preamplifier Power Connector Pinout..............................................................................................................B-1
B3 Digital Output Port Connector..........................................................................................................................B-2
Appendix C, Cable Diagrams
C1 RS232 Cable Diagrams......................................................................................................................................C1
Appendix D, Default Settings
Auto Default Function.............................................................................................................................................D1

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Appendix E, 7124/99 DC Power Option for 7124 RCU
E.1 Introduction....................................................................................................................................................... E1
E.2 7124 RCU POWER Connector......................................................................................................................... E1
E.3 7124/99 DC Power Input Cable........................................................................................................................ E1
E.4 Operation .......................................................................................................................................................... E2
E.5 DC Power Over- and Under- Voltage Protection ............................................................................................. E2
E.6 Line Power/DC Input Power Switching ........................................................................................................... E3
Appendix F, Alphabetical Listing of Commands
Index
Warranty...................................................................................................................................... End of Manual

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vii
GENERAL SAFETY PRECAUTIONS
The equipment described in this manual has been designed in accordance with EN61010 "Safety
requirements for electrical equipment for measurement, control and laboratory use", and has been
supplied in a safe condition. To avoid injury to an operator or service technician the safety precautions
given below, and throughout the manual, must be strictly adhered to, whenever the equipment is
operated, serviced or repaired. For specific safety details, please refer to the relevant sections within
the manual.
The equipment is intended solely for electronic measurement and should be used for no other purpose.
SIGNAL RECOVERY accepts no responsibility for accidents or damage resulting from any failure to
comply with these precautions.
Grounding
To minimize the hazard of electrical shock, it is essential that the equipment be connected to a
protective ground through the AC supply cable. The continuity of the ground connection should be
checked periodically.
AC Supply Voltage
Never operate the equipment from a line voltage or frequency in excess of that specified. Otherwise,
the insulation of internal components may break down and cause excessive leakage currents.
Fuses
Before switching on the equipment check that the fuses accessible from the exterior of the equipment
are of the correct rating. The rating of the AC line fuse must be in accordance with the voltage of the
AC supply.
Should any fuse continually blow, do not insert a fuse of a higher rating. Switch the equipment off,
clearly label it "unserviceable" and inform a service technician.
Explosive Atmospheres
This equipment must NEVER BE OPERATED in a potentially explosive atmosphere. The equipment is
NOT designed for use in these conditions and could possibly cause an explosion.
Safety Symbols
For the guidance and protection of the user, the following safety symbols may appear on the
equipment, together with details of the hazard where appropriate:
Symbol
Meaning
General safety hazard. Refer to the operating manual for detailed instructions.
Electrical safety hazard. This symbol may appear alongside the general safety
hazard symbol, together with a voltage.
Notes and Cautions
For the guidance and protection of the user, Notes and Cautions appear throughout the manual. The
significance of these is as follows:
NOTES highlight important information for the reader’s special attention.
CAUTIONS guide the reader in avoiding damage to the equipment.

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viii
Avoid Unsafe Equipment
The equipment may be unsafe if any of the following statements apply:
Equipment shows visible damage.
Equipment has failed to perform an intended operation.
Equipment has been stored in unfavorable conditions.
Equipment has been subjected to severe physical stress.
If in any doubt as to the serviceability of the equipment, don't use it. Get it properly checked out by a
qualified service technician.
Live Conductors
When the equipment is connected to its measurement inputs or supply, the opening of covers or
removal of parts could expose live conductors. The equipment must be disconnected from all power
and signal sources before it is opened for any adjustment, replacement, maintenance or repair.
Adjustments, maintenance or repair must only be done by qualified personnel, who should refer to the
relevant maintenance documentation.
Equipment Modification
To avoid introducing safety hazards, never install non-standard parts in the equipment, or make any
unauthorized modification. To maintain safety, always return the equipment to your
SIGNAL RECOVERY service provider for service and repair.
European WEEE Directive
This product is subject to Directive 2002/96/EC of the European Parliament and the Council of the
European Union on waste electrical and electronic equipment (WEEE) and, in jurisdictions adopting
that Directive, is marked as being put on the market after August 13, 2005, and should not be disposed
of as unsorted municipal waste. Please use your local WEEE collection facilities for the disposal of this
product and otherwise observe all applicable requirements.
FCC Notice
This equipment generates, uses, and can radiate radio frequency energy and, if not installed and used
in accordance with this instruction manual, may cause harmful interference with radio communications.
Operation of this equipment in a residential area is likely to cause harmful interference, in which case
the user is required to correct the interference at his own expense.
Acknowledgment
Operation of the Ethernet interface in the model 7270 relies on software code developed by the
Swedish Institute of Computer Science, copyright 2001-2004, all rights reserved. In accordance with
the license under which it is used, we reproduce here the following disclaimer:
THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES,
INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT,
INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.