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Signal Recovery 7210 Instruction Manual

Multi-channel dsp lock-in amplifier
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Model 7210
Multi-Channel
DSP Lock-in Amplifier
Instruction Manual
190480-A-MNL-F
Acknowledgement
This instrument was originally developed in conjunction with:
Dr E. Tokunaga
Masumoto Single Quantum Dot Project
Japan Science and Technology Corporation
Tsukuba Research Consortium
5-9-9 Tokodai
Tsukuba
Ibaraki 300-2635
Japan
Copyright © 2013 AMETEK ADVANCED MEASUREMENT TECHNOLOGY, INC

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  • Page 1 Model 7210 Multi-Channel DSP Lock-in Amplifier Instruction Manual 190480-A-MNL-F Acknowledgement This instrument was originally developed in conjunction with: Dr E. Tokunaga Masumoto Single Quantum Dot Project Japan Science and Technology Corporation Tsukuba Research Consortium 5-9-9 Tokodai Tsukuba Ibaraki 300-2635 Japan...

  • Page 2: Fcc Notice

    Company Names SIGNAL RECOVERY is part of Advanced Measurement Technology, Inc, a division of AMETEK, is part of Advanced Measurement Technology, Inc, a division of AMETEK, is part of Advanced Measurement Technology, Inc, a division of AMETEK, Inc.

  • Page 3: Table Of Contents

    Table of Contents Table of Contents 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 ........................1-2 Chapter Two, Installation & Initial Checks 2.1 Installation ................................ 2-1 2.1.01 Introduction .............................
  • Page 4 5.4 Programming Examples ..........................5-26 5.4.01 Introduction ............................5-26 5.4.02 Basic Signal Recovery - Single Reference Mode .................. 5-26 5.4.03 Basic Signal Recovery - Tandem Reference Mode ................5-26 5.4.04 Tandem Reference Mode with Output Data Sampling Correlation ............5-27...
  • Page 5 TABLE OF CONTENTS Appendix B, Pinouts B1 RS232 Connector Pinout ..........................B-1 B2 Digital Output Port Connector .......................... B-1 B3 Preamplifier Power Connector Pinout ......................B-1 Appendix C, Demonstration Programs C1 Simple Terminal Emulator ..........................C-1 C2 RS232 Control Program with Handshakes ....................... C-1 C3 GPIB User Interface Program ...........................

  • Page 7: Chapter One, Introduction

    1.1 How to Use This Manual This manual gives detailed instructions for setting up and operating the SIGNAL RECOVERY Model 7210 Multi-Channel Digital Signal Processing (DSP) dual phase lock-in amplifier. It is split into the following chapters:- Chapter 1 - Introduction...

  • Page 8: What Is A Lock-In Amplifier

    The model 7210, with its use of the latest technology, allows up to 32 signals to be measured simultaneously. What is more, units can be linked together to give more detection channels.
  • Page 9 Chapter 1, INTRODUCTION per channel. This detection method would previously have required two lock-in amplifiers connected in series, so in this mode the 32-channels of the 7210 are equivalent to 64 dual phase lock-in amplifiers. To date, no other commercially available instrument matches this capability.

  • Page 11: Installation

    2.1.04 Line Voltage Selection and Line Fuses Before plugging in the line cord, ensure that the model 7210 is set to the voltage of the AC power supply to be used. A detailed discussion of how to check and, if necessary, change the line voltage setting follows.
  • Page 12 Chapter 2, INSTALLATION & INITIAL CHECKS showing is incorrect for the prevailing line voltage (refer to table 2-1), then the barrel selector will need to be repositioned as follows. Observing the instrument from the rear, note the plastic door immediately adjacent to the line cord connector (figure 2-1) on the right-hand side of the instrument.

  • Page 13: Initial Checks

    SIGNAL RECOVERY or the nearest authorized representative for assistance. 2.2.02 Procedure 1) Ensure that the model 7210 is set to the line voltage of the power source to be used, as described in section 2.1.05. Figure 2-2, Model 7210 GPIB Address and...
  • Page 14 1.000 kHz 12) If the unit is fitted with voltage mode input signal boards (7210/99), set the signal generator output amplitude to 1 V rms and apply this to the front panel signal input connector marked "1".
  • Page 15 ±500 counts, depending on the real level of applied signal. 14) Turn off the model 7210 and, if the DIP switch settings were changed at step 2, restore them to their initial values.

  • Page 17: Introduction

    X output of one to the input of the second. However, the 7210 includes this capability as a standard feature, subject to only a few limitations. In order to allow the second demodulator to run synchronously with the first, it is desirable for its reference frequency to be the result of an integer division of the first reference frequency.

  • Page 18: Principles Of Operation

    Consequently the 7210 is fitted with two reference connectors; REF 1 IN is used to apply the external reference frequency at which the first demodulation stage operates, and the second.

  • Page 19: Signal Channel Inputs

    In this case the input amplifier is a buffer stage with an input impedance of 10 MΩ. The frequency response (-3 dB) extends from 20 Hz to 50.5 kHz 7210/98 Signal Board - Wide Bandwidth Current Mode Inputs In this case the input amplifier is a single-ended current mode device with a fixed transimpedance setting of 10E6 V/A.

  • Page 20: Anti-Aliasing Filter

    × DR(in log(DR(as ratio Applying this formula to the model 7210 at the maximum value of INPUT LIMIT and the smallest available value of FULL-SCALE SENSITIVITY, gives a maximum available dynamic reserve of better than 80 dB. 3.3.04 Anti-Aliasing Filter...

  • Page 21: Main Analog-To-Digital Converter

    60 dB. In a typical low-level signal recovery situation, many unwanted inputs need to be dealt with and it is normal practice to make small adjustments to the reference frequency until a clear point on the frequency spectrum is reached.

  • Page 22: Reference Channel

    Chapter 3, TECHNICAL DESCRIPTION 3.3.06 Reference Channel The reference channel contains the reference trigger/phase-locked loop, a reference multiplier and a reference divider, and two digital phase-shifters per signal channel. (see figure 3-1). In single reference mode, the reference channel locks to the applied external reference signal and its output, referred to REF 1, is fed either directly or via a 2F frequency multiplier to all 32 of the phase shifters used for the first stage of demodulation.

  • Page 23: Main Microprocessor - General

    12 dB per octave. This term has become part of the accepted terminology relating to lock-in amplifier output filters and is used in the model 7210 to apply to the envelope of the frequency response function of the FIR output filters. For the sake of simplicity, all the filters in the 7210 have a fixed slope of 12dB/octave.
  • Page 24 Auto-Default With an instrument of the complexity of the model 7210 where there are many controls of which only a few are regularly adjusted, it is very easy to overlook the setting of one of them. Consequently an Auto-Default function is provided, which sets all the controls to a defined state.

  • Page 25: Main Microprocessor - Curve Buffer

    5 kHz. 3.4.02 Power-up Defaults Unlike most other SIGNAL RECOVERY lock-in amplifiers, instrument settings are not retained on power down. Consequently the user must ensure that all controls are reset as required by the controlling program each time the instrument is...

  • Page 27: Front Panel

    7210 with the final set of channels (e.g. channels 97 applied to the 7210 with the final set of channels (e.g. channels 97 applied to the 7210 with the final set of channels (e.g. channels 97 - 128 in a 128- channel system).

  • Page 28: Trig 1 And Trig 2 Connectors

    Chapter 4, FRONT & REAR PANELS 4.1.04 TRIG 1 and TRIG 2 Connectors The TRIG 1 connector is a TTL input used for triggering data acquisition to the internal curve buffer, when this has been configured and armed using the TDT (take data triggered) command.

  • Page 29: Rear Panel

    Chapter 4, FRONT & REAR PANELS 4.2 Rear Panel Figure 4-2, Model 7210 Rear Panel Layout As shown in figure 4-2, the line power switch, line power voltage selector, RS232 connector, GPIB (IEEE-488) connector, digital output port and two RJ45 multipole connectors, and a preamplifier power connector are mounted on the rear panel of the instrument.

  • Page 30: Preamp Power Connector

    32 signal channels. A cable should be connected from the LINK 2 socket on the 7210 that is set to be the Master unit to the LINK 1 socket on the second unit, configured as a Slave. If more than two 7210's are interconnected, then the LINK 2 socket on the first Slave should be coupled to the LINK 1 socket on the second Slave, and so on.

  • Page 31: Introduction

    BASIC code (see appendix C.1). 5.2.02 RS232 Interface - General Features The RS232 interface in the model 7210 is implemented with three wires; one carries digital transmissions from the computer to the lock-in amplifier, the second carries digital transmissions from the lock-in amplifier to the computer and the third is the Logic Ground to which both signals are referred.

  • Page 32: Choice Of Baud Rate

    1 stop bit. The rate of data transfer depends on the number of bits per second sent over the interface, usually called the baud rate. In the model 7210 the baud rate can be set to a range of different values up to 19,200, corresponding to a minimum time of less than 0.5 ms for a single character.

  • Page 33: Choice Of Parity Check Option

    Chapter 5, COMPUTER OPERATION 5.2.05 Choice of Parity Check Option Parity checks are not required at the baud rates available in the model 7210, that is up to 19,200 baud, with typical cable lengths of up to a few meters. Therefore no software is provided in the model 7210 for dealing with parity errors.
  • Page 34 RD input). However, these lines are not capable of implementing the handshaking function required by the model 7210 on a byte-by-byte basis and are not connected in the model 7210 apart from the RTS and DTR outputs which are constantly asserted.

  • Page 35: Terminators

    In the model 7210 there are three input termination options for GPIB communications, selected by means of the GP command. The lock-in amplifier may be set to expect the <CR>...

  • Page 36: Delimiters

    6 (the request service bit) whose functions are defined by the standard. In the model 7210, bits 0 and 7 signify "command complete" and "data available" respectively. In GPIB communications, the use of these bits can lead to a useful...
  • Page 37 Chapter 5, COMPUTER OPERATION bus. The subroutine should carry out the following sequence of events: 1) Send the command 2) Perform repeated serial polls testing both bit 0 (command complete) and bit 7 (data available) and, if bit 7 is asserted then perform a read operation. This cycle (i.e.

  • Page 38: Service Requests

    In the model 7210 the assertion of the SRQ line is under the control of a byte called the SRQ mask byte which can be set by the user with the MSK command or via the GPIB Settings menu.

  • Page 39: Signal Channel

    Chapter 5, COMPUTER OPERATION 5.3.01 Signal Channel ACGAIN n AC Gain control Sets or reads the gain of the signal channel amplifier. Values of n from 0 to 6 can be entered, corresponding to the range 0 dB to 60 dB in 10 dB steps. SEN1 n SEN1.
  • Page 40 Chapter 5, COMPUTER OPERATION SEN2 n SEN2. n Full-scale sensitivity control In tandem mode, the value of n sets the full-scale sensitivity of the second stage demodulator(s) for the channel(s) specified by n according to the following table: full-scale sensitivity Voltage Mode Wideband Current Mode Low Noise Current Mode 100 µV 100 pA...
  • Page 41 Chapter 5, COMPUTER OPERATION When the command is sent without the parameter "n", the instrument automatically calculates the optimum offset for each channel and applies it, with the value remaining in effect until next changed or until the instrument is powered down. The command also operates, for diagnostic purposes only, so that when sent with a parameter "n"...

  • Page 42: Reference Channel

    Chapter 5, COMPUTER OPERATION 5.3.02 Reference Channel FRQ1[.] Reference frequency meter The FRQ1 command causes the lock-in amplifier to respond with 0 if the main (first stage) reference channel is unlocked, or with the reference input frequency if it is locked.

  • Page 43: Signal Channel Output Filters

    Chapter 5, COMPUTER OPERATION (second stage) demodulator(s) in millidegrees in the range ±360000. In floating point mode n sets the phase of the channel(s) specified by n in degrees. AQN1 n Auto-Phase (auto quadrature null) Main (first stage) demodulator(s) AQN2 n Auto-Phase (auto quadrature null) Tandem (second stage) demodulator(s) 5.3.03 Signal Channel Output Filters...

  • Page 44: Instrument Outputs

    Chapter 5, COMPUTER OPERATION 5.3.04 Instrument Outputs X channel output - Main (first stage) - Binary Mode This command causes the lock-in amplifier to respond with 64 bytes of data being the X1 demodulator output for all 32 channels. Each value is a sixteen-bit signed integer in the range ±30000, full-scale being ±10000, represented by two bytes in the order High Byte - Low Byte, with the data being transferred in the order Channel 1 to Channel 32.

  • Page 45: Auxiliary Output

    Chapter 5, COMPUTER OPERATION output of the channel(s) specified by n in the range ±30000, full-scale being ±10000. In floating point mode causes the lock-in amplifier to respond with the Y1 demodulator output of the channel(s) specified by n in amps. Y2[.] n Y channel output - Tandem (second stage) In fixed point mode causes the lock-in amplifier to respond with the Y2 demodulator...
  • Page 46 Chapter 5, COMPUTER OPERATION Reference Frequency F2 = (65536 × value in Curve 7) + (value in Curve 6) Note that the CBD command directly determines the allowable parameters for the DC and DCB commands. It also interacts with the LEN command and affects the values reported by the M and MAXLEN commands.
  • Page 47 Chapter 5, COMPUTER OPERATION the TRIG IN 1 connector on the front panel. Two triggered modes are possible, as set by the value of n: function One complete set of curves, consisting of the number of curve sets specified by the LEN command parameter, is acquired for each trigger One curve is acquired for each trigger.
  • Page 48 Chapter 5, COMPUTER OPERATION Curve acquisition status monitor Causes the lock-in amplifier to respond with four values that provide information concerning data acquisition, as follows: First value, Curve Acquisition Status: a number with five possible values, defined by the following table: First Value Significance No curve activity in progress.
  • Page 49 Chapter 5, COMPUTER OPERATION Each curve is separated from the next by a <CR><LF> (carriage return and line feed character pair). In the case of the other curve sets, the command simply returns (setting of the LEN control) values, again with each one being separated from the next by a <CR><LF> character pair.
  • Page 50 Chapter 5, COMPUTER OPERATION , Y2 , Y2 , Y2 , Y2 , Y2 , Y2 , .., Y2 , Y2 (curve 2) , X1 , X1 , X1 , X1 , X1 , X1 , .., X1 , X1 (curve 3) , Y2 , Y2...
  • Page 51 Chapter 5, COMPUTER OPERATION DCB n Dump acquired curve sets to computer in binary format This command causes a stored curve set to be dumped via the computer interface in binary format, using two bytes per point to transfer each 16-bit 2’s complement value, with the MSB transmitted first.
  • Page 52 Chapter 5, COMPUTER OPERATION , X1 , X1 , X1 , X1 , X1 , X1 , .., X1 , X1 (curve 1) , Y2 , Y2 , Y2 , Y2 , Y2 , Y2 , .., Y2 , Y2 (curve 1) , X1 , X1...

  • Page 53: Computer Interfaces (Rs232 And Gpib)

    Data is being transferred to output buffers within the model 7210 - normal mode Data transfer to output buffers within the model 7210 suspended, because either a GET 1 command or a GPIB Group Execute Trigger command has been...
  • Page 54 Chapter 5, COMPUTER OPERATION GP [n] Set/Read GPIB parameters Terminator [CR], test echo disabled [CR], test echo enabled [CR,LF], test echo disabled [CR,LF], test echo enabled no terminator, test echo disabled no terminator, test echo enabled Note that the GPIB address is set via the rear-panel DIP switches. RS [n Set/read RS232 interface parameters Baud rate (bits per second)

  • Page 55: Instrument Identification

    The value of n sets the SRQ mask byte in the range 0 to 255 5.3.08 Instrument Identification Identification Causes the lock-in amplifier to respond with the number 7210. CARDID Signal Board Identification The response to the CARDID command is 8 numbers, separated by the selected delimiter.

  • Page 56: Programming Examples

    This section gives some examples of the commands that need to be sent to the lock-in amplifier for typical experimental situations. 5.4.02 Basic Signal Recovery - Single Reference Mode In a typical simple experiment, the computer is used to set the instrument controls and then to record the chosen outputs, perhaps as a function of time.

  • Page 57: Tandem Reference Mode With Output Data Sampling Correlation

    Chapter 5, COMPUTER OPERATION this could take a long time, up to several minutes, to complete. TC1 0 3 Set time constants to 100 ms, since previous ASM sets the TC to 300 ms changed them TC2 0 3 Set time constants to 100 ms, since previous ASM will have set the TC as a function of the REF 2 OUT reference frequency.
  • Page 58 Chapter 5, COMPUTER OPERATION X1. 0 Reads 32 X1 channel output values in amps Y1. 0 Reads 32 Y1 channel output values in amps X2. 0 Reads 32 X2 channel output values in amps Y2. 0 Reads 32 Y2 channel output values in amps Having read all required data, send to the Master Unit:- GET 0 and to the Slave Unit:-...

  • Page 59: Appendix A, Specifications

    (e.g. the components at say 10 Hz) Signal Channel The signal input specifications depend on the model of signal board fitted. Three board types are available: 7210/99 Signal Board - Voltage Mode Inputs Voltage Mode Virtual Ground Connector 0 Ω...
  • Page 60 Appendix A, SPECIFICATIONS (9 settings) 7210/98 Signal Card - Wide Bandwidth Current Mode Inputs Current Input Mode Virtual Ground Connector 0 Ω Impedance to Ground ≤ 1 kΩ at 1 kHz to Input Impedance virtual ground Input Current Noise < 150 fA/√Hz at 1 kHz ±...
  • Page 61 Appendix A, SPECIFICATIONS Reference Channel External Reference Input Impedance 1 MΩ//35 pF Level 250 mV to 2.5 V rms Connector Frequency Range, f1 20 Hz to 50.5 kHz Lock Acquisition Time 2 seconds max Reference Phase Shifter Set Resolution 10 m° Orthogonality 90°...
  • Page 62 Appendix A, SPECIFICATIONS Tandem-Frequency Operation Applying to f1 outputs:- Time Constants 4 ms to 1 ks in 1-3-10 sequence (12 steps) Slope 12 dB/octave Type Synchronous digital FIR filters Applying to f2 outputs:- Time Constants 30 ms to 1 ks in 1-3-10 sequence (11 steps) Slope 12 dB/octave...
  • Page 63 Appendix A, SPECIFICATIONS and that its synchronizing signal connectors are outputs Internal Oscillator - reserved for future expansion. Reference Unlock - lights when no suitable reference is applied Signal Channel Overload - a single LED warning of any one of the 32 channels being in overload.

  • Page 65: Appendix B, Pinouts

    Pinouts Appendix B1 RS232 Connector Pinout Figure B-1, RS232 and AUX RS232 Connector (Female) Function Description Data In Data Out Signal Ground Request to Send - Always +12 V All other pins are not connected B.2 Digital Output Port Connector Figure B-2, Digital Output Port Connector 8-bit TTL-compatible output set from the front panel or via the computer interfaces.

  • Page 66: B3 Preamplifier Power Connector Pinout

    Appendix B, PINOUTS Function Ground +5 V +5 V D0 = Least Significant Bit D7 = Most Significant Bit B.3 Preamplifier Power Connector Pinout Figure B-3, Preamplifier Power Connector Function -15 V Ground +15 V Pins 4 and 5 are not connected. Shell is shield ground.

  • Page 67: Appendix C, Demonstration Programs

    Demonstration Programs Appendix C.1 Simple Terminal Emulator This is a short terminal emulator with minimal facilities, which will run on a PC-compatible computer in a Microsoft GWBASIC or QuickBASIC environment, or can be compiled with a suitable compiler. 10 'MINITERM 9-Feb-96 20 CLS : PRINT "Lockin RS232 parameters must be set to 9600 baud, 7 DATA bits, 1 stop bit and even parity"...
  • Page 68 Appendix C, DEMONSTRATION PROGRAMS 160 ' 170 ' 180 '...output the string B$....190 ON ERROR GOTO 510 ' enable error trapping 200 IF LOC(1) > 0 THEN A$ = INPUT$(LOC(1), #1) ' clear input buffer 210 ON ERROR GOTO 0 ' disable error trapping 220 FOR J1% = 1 TO LEN(B$) ' LEN(B$) is number of bytes...

  • Page 69: C3 Gpib User Interface Program

    Appendix C, DEMONSTRATION PROGRAMS C.3 GPIB User Interface Program GPCOM.BAS is a user interface program which illustrates the principles of the use of the serial poll status byte to coordinate the command and data transfer. The program runs under Microsoft GWBASIC or QuickBASIC on a PC-compatible computer fitted with a National Instruments IEEE-488 interface card and the GPIB.COM software installed in the CONFIG.SYS file.
  • Page 70 Appendix C, DEMONSTRATION PROGRAMS 300 '..set status print flag......310 INPUT "Display status byte y/n "; R$ 320 IF R$ = "Y" OR R$ = "y" THEN DS% = 1 ELSE DS% = 0 330 '..main loop........340 WHILE 1 ' infinite loop INPUT "command (00 to exit) ";...

  • Page 71: Appendix D, Cable Diagrams

    Appendix D.1 RS232 Cable Diagrams Although in normal use the 7210 is controlled via the GPIB interface, it is useful for diagnostic purposes and necessary for firmware upgrades to be able use the RS232 interface as well. In order to connect the instrument to a standard serial port on a computer one of two types of cable is needed.
  • Page 72 Appendix D, CABLE DIAGRAMS Figure D-2, Interconnecting RS232 Cable Wiring Diagram...

  • Page 73: Appendix E, Alphabetical Listing Of Commands

    Alphabetical Listing of Commands Appendix In the following commands the parameter n is commonly used to signify which channel(s) of the 32 within the instrument will be affected by the command, as follows:- Significance All 32 channels are set to the same value Channel 1 Channel 2 31 Channel 31...
  • Page 74 Appendix E, ALPHABETICAL LISTING OF COMMANDS ASM n Perform an Auto-Measure operation Operates on both the main (first stage) and tandem (second stage) demodulator(s) Note: The auto-sensitivity and auto-measure operations can take a significant time (in some cases over a minute) per channel to complete, so they should be used with care.
  • Page 75 Appendix E, ALPHABETICAL LISTING OF COMMANDS No card fitted Wide Bandwidth current mode input (10E6 transimpedance) Voltage Mode input Low Noise current mode input (10E7 transimpedance) For example a response of 3,3,3,3,3,3,3,3 means that the unit is fitted with 32 channels, each having a low-noise current mode input stage.
  • Page 76 Appendix E, ALPHABETICAL LISTING OF COMMANDS One curve set only is transferred, as specified by the parameter n, which is the bit number of the required set and which must have been stored by the most recent CBD command. Data is transmitted one curve at a time, starting from the beginning of the buffer.
  • Page 77 Appendix E, ALPHABETICAL LISTING OF COMMANDS , X1 , X1 , X1 , X1 , X1 , X1 , .., X1 , X1 (X1 values) , Y1 , Y1 , Y1 , Y1 , Y1 , Y1 , .., Y1 , Y1 (Y1 values) FRQ1...
  • Page 78 Appendix E, ALPHABETICAL LISTING OF COMMANDS CBD command. Data is transmitted one curve at a time, starting from the beginning of the buffer. In the case of curves with 32 Values/Curve (i.e. curves 0, 1, 4 and 5) the response consists of a total of 32 × (setting of the LEN control) values, ordered as follows (example for curve 0, with length of 100 points): , X1 , X1...
  • Page 79 Appendix E, ALPHABETICAL LISTING OF COMMANDS available. Read this data with another read of 1024 bytes. Repeat this process, tracking the number of curve sets received, until there are only four left (i.e. after 12 groups). The final read will then need to be of (32 x 2 x 2 x 4) bytes (256 bytes) to complete the transfer.
  • Page 80 Data is being transferred to output buffers within the model 7210 - normal mode Data transfer to output buffers within the model 7210 suspended, because either a GET 1 command or a GPIB Group Execute Trigger command has been...
  • Page 81 The curve may be restarted by means of the TD, TDT or TDC command, as appropriate. Identification Causes the lock-in amplifier to respond with the number 7210. LEN [n] Curve sets length control The value of n specifies the curve sets buffer length in effect for data acquisition. The maximum value is 2,000,000,000, although this is only useful if using the DCFIFO or DCBFIFO readout commands.
  • Page 82 Appendix E, ALPHABETICAL LISTING OF COMMANDS Third value, Status Byte: The same as the response to the ST command. The number returned is the decimal equivalent of the status byte and refers to the previously applied command. Fourth value, Number of Curves Available for Transfer: This number is incremented each time a curve is taken.
  • Page 83 Appendix E, ALPHABETICAL LISTING OF COMMANDS binary number with the following bit-significance: Bit 0 input overload Bit 1 X1 channel output overload (> ±300 %FS) Bit 2 Y1 channel output overload (> ±300 %FS) Bit 3 X2 channel output overload (> ±300 %FS) Bit 4 Y2 channel output overload (>...
  • Page 84 Appendix E, ALPHABETICAL LISTING OF COMMANDS Baud rate (bits per second) 1200 1800 2000 2400 10 4800 11 9600 12 19200 The lowest five bits in n control the other RS232 parameters according to the following table: bit number bit negated bit asserted data + parity = 8 bits data + parity = 9 bits...
  • Page 85 Appendix E, ALPHABETICAL LISTING OF COMMANDS In either mode, SEN1. n reads the sensitivity of the channel(s) specified by n floating-point mode. SEN2 n SEN2. n Full-scale sensitivity control In tandem mode, the value of n sets the full-scale sensitivity of the second stage demodulator(s) for the channel(s) specified by n according to the following table: full-scale sensitivity...
  • Page 86 Appendix E, ALPHABETICAL LISTING OF COMMANDS If Bit 4 is asserted, the OVL command can be used to determine where the overload is occurring. NOTE: this command is not normally used in GPIB communications, where the status byte is accessed by performing a serial poll. STR [n] Storage interval control Sets the time interval between successive curve sets being acquired under the TD or...
  • Page 87 Appendix E, ALPHABETICAL LISTING OF COMMANDS The TC2. n command is only used for reading the time constant, and reports the current setting in seconds. Hence if a TC2 1 3 command were sent, TC2 1 would report 3 and TC2. 1 would report 1.0E-01, i.e. 0.1 s or 100 ms. Take data Initiates data acquisition.
  • Page 88 Appendix E, ALPHABETICAL LISTING OF COMMANDS XY1[.] n X, Y channel outputs - Main (first stage) Equivalent to the compound command X1[.]n ;Y1[.]n XY2[.] n X, Y channel outputs - Tandem (second stage) Equivalent to the compound command X2[.]n ;Y2[.]n Y1[.] n Y channel output - Main (first stage) In fixed point mode causes the lock-in amplifier to respond with the Y1 demodulator...

  • Page 89: Index

    Index Index 8-bit programmable output port 3-8 Computer operation,introduction 5-1 AC Gain Curve buffer and effect on accuracy 3-10 introduction 3-10 and full scale sensitivity 3-5 Curve storage and input overload 3-4 commands for 5-15 AUTOMATIC control 3-5 Data storage description of 3-4 programming examples 5-27 Accuracy 3-10...
  • Page 90 INDEX connectors 4-1 handshaking and echoes 5-3 Inspection 2-1 OVL (locate overload) command 5-6 Key specifications 1-2 OVR (report overload) command 5-6 LEN [n] command 5-16, E-9 prompts 5-6 Line cord 2-1 ST (status) command 5-6 Line power input assembly 4-3 terminators 5-5 Line power switch 4-3 SEN1 n...

  • Page 91: Warranty

    SHOULD YOUR EQUIPMENT REQUIRE SERVICE A. Contact your local SIGNAL RECOVERY office, agent, representative or distributor to discuss the problem. In many cases it may be possible to expedite servicing by localizing the problem to a particular unit or cable.

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