Anfatec eLockIn 203 Manual

Dual input 4-phase dsp lock-in amplifier

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dual input 4-phase DSP lock-in amplifier

OCK

PECTRUM

ATA

IGITAL

eLockIn 203

models produced after 01/2014

–

Manual

-I

MPLIFIER

NALYZER

CQUISITION

SCILLOSCOPE

November 2014

Anfatec Instruments AG

Melanchthonstr. 28

08606 Oelsnitz /V.

Tel.: +49 (0) 37421 24212

Tel.: +49 (0) 37421 24221

http://www.anfatec.de

email:

mailbox@anfatec.de

1 (58)

–

250

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Page 1 203 dual input 4-phase DSP lock-in amplifier models produced after 01/2014 – – Manual MPLIFIER MPLIFIER PECTRUM NALYZER PECTRUM NALYZER CQUISITION CQUISITION IGITAL SCILLOSCOPE IGITAL SCILLOSCOPE November 2014 Anfatec Instruments AG Melanchthonstr. 28 08606 Oelsnitz /V. Tel.: +49 (0) 37421 24212 Tel.: +49 (0) 37421 24221...
Page 2: Table Of Contents
ABLE OF ONTENTS 1 Introduction........................5 1.1 General Functions....................5 1.2 Specifications eLockIn203..................7 1.2.1 Lock-In Amplifier......................7 1.2.2 Oscilloscope:........................9 1.2.3 AUX In:........................9 1.2.4 AUX Out:........................9 2 Lock-In Basics......................10 2.1 Lock-In Amplification....................10 2.2 Mathematical Description..................10 2.3 Characteristical Curves of a Lock-In Amplifier............12 2.4 Noise Measurements.....................13 2.5 Example: Electrical Force Microscope..............14 3 Users manual.......................16 3.1 Technical introduction...................16...
Page 3 4.5.1 TCP/IP access by LabView...................46 4.5.2 DLL based access by LabView..................48 5 Software-Update......................50 6 Revision History......................51 6.1 Manual Revisions....................51 6.2 Hardware Revisions....................51 6.3 Software revision....................51 7 Appendices........................52 7.1 Schematic diagram of the signal paths..............52 7.2 Diagram of the lockin amplification paths...............53 7.3 Frontpanel Dimensions..................54 7.4 Instrument Specific Test Sheets................55 7.5 Preamplifier Connector Pinout................56...
Page 4 Be sure to make backup copies of all important data on other media to protect against data loss. Using any part of the software indicates that you accept the terms of Anfatec Software License Agreement.
Page 5: Introduction
1 INTRODUCTION 1.1 G ENERAL UNCTIONS The eLockIn203 is a versatile scientific instrument that supports the following functions: LockIn Amplifier Digital Oscilloscope Spectrum Analyzer Data Acquisition The instrument works as a stand-alone device with a 5.6 inches TFT display. Its internal functionality is best described with the following overall schematics: Figure 1: Schematic diagram with the basic components of the lock-in amplifier (see page 52).
Page 6 Figure 2: Schematic of the input stage describing the switching between the three input modes A, and A &B as well as the position of the input amplification stages in order to realize the three different input gains. The signals which have to be analyzed run through analogue amplification stages whose 3 dB bandwidth is 250 kHz.
Page 7: Specifications Elockin203
1.2 S PECIFICATIONS E 1.2.1 L MPLIFIER General Digital Quad-Phase Lock-In Amplifier Dynamic Reserve 135 dB Noise (single ended A) < 5 nV @ 100kHz Remote Control Ethernet Time Constants 0.1 ms ... 1 ks Full Scale Sensitivity 10 nV ... 10 V in 1-2-5 sequence Phase Resolution 0.0001°...
Page 8 Current Input (Optional) Current Input (optional) BNC (for A-input, only) Input Coupling Damage Threshold 0.12 mA Full Scale Input Ranges ± 350 nA , ± 3.5 µA Input amplifications 1 MΩ Bandwidth dc to 1 MHz Current Input Noise @ U = 0 V, τ...
Page 9: Oscilloscope
1.2.2 O SCILLOSCOPE Available Channels Lock-in channels of 1 input RA, ϕΑ, XA, YA external A/D-channels AD1 to AD8 internal data channels f, U , In internal D/A-channels DA5 to DA8 Lock-in channels of 2 input RB, ϕΒ, XB, YB in “A&B” Rn, ϕn, Xn, Yn in “A”...
Page 10: Lock-In Basics
2 LOCK-IN BASICS 2.1 L MPLIFICATION The lock-in amplifier is a measuring instrument for extracting and amplifying low signals from noise by means of a correlation analysis. For this method, it is necessary to know about the time dependence of the signal to be measured. Practically this signal is modulated at a certain reference frequency ω...
Page 11 ... (1 , ... harmonic) are expected. For that reason the lock-in amplifier calculates the following Fourier components S(m·ω ) in the frequency domain from the input signal s(t) in the time domain: / 2 ∫ −i m  S  m⋅ s ...
Page 12: Characteristical Curves Of A Lock-In Amplifier
2.3 C HARACTERISTICAL URVES OF A MPLIFIER For filtering different information out of a received signal the corresponding frequency ranges ought not to overlap. The following experiment shows how small the difference between the frequencies should be that they can be analyzed independently: A sinusoidal signal with a frequency of 100 kHz and an amplitude of 20 mV is fed in to the input of the lock-in amplifier.
Page 13: Noise Measurements
2.4 N OISE EASUREMENTS Lock-in amplifiers are capable to measure noise. They detect a signal at a certain center frequency ω with an equivalent noise bandwidth. For a Gaussian noise, the equivalent noise bandwidth of a real low pass filter is the bandwidth which passes the same amount of noise as a perfect rectangular filter with the equivalent noise band width.
Page 14: Example: Electrical Force Microscope
2.5 E XAMPLE LECTRICAL ORCE ICROSCOPE In this chapter electrical force microscopy (EFM) is briefly presented as an example for the application of lock-in amplifiers. EFM is a related technique to the well-established atomic force microscopy (AFM). Its special aim is to detect electrical forces to learn something about the electrical properties of a surface, for example about the local distribution of surface potentials on electronic devices or different dopant concentrations in semi-conducting materials.
Page 15 = − A possible voltage dependency of C is neglected in this consideration. The voltage U contains a direct voltage part U and an alternating voltage part U U = U  U t  ⋅cos consists of an additional applied bias voltage and, what is especially interesting from the physical point of view, potential differences caused by different electronic work functions and charges.
Page 16: Users Manual
3 USERS MANUAL This manual part describes where to find and how to change a parameter. It also gives an overview of the front panel and rear panel structure. An abbreviation like [LockIn / Ref / f] means that the user has to press the buttons “LockIn” → “Ref” →...
Page 17: Screen Organization
signal and the scaling of the DA-channels can be modified here. Spectra: This is the control key for the Spectra acquisition mode. The displayed LockIn channels are selected in the mode. Scope: Press this button to turn the instrument into Oscillos cope mode.
Page 18: The Menu Tree
name This entry consists of a only. It usually leads to a sub-menu. 3.1.3 T The five top base menus are selected with the Menu Selection buttons displayed in Figure 6 on page 16. The sub-menus are shown in the following pictures: [LockIn] When is pressed, the first line of the menu structure mentioned in Figure 8...
Page 19 Spectra Display Acquire Save Axis Type Dest. Type f1 [kHz] Name Color f2 [kHz] Save Offset Point -> Ref Delay Figure 9: Menu structure of the Spectra mode. The knobs Measure Setup do not provide a deep menu structure. In order to understand the meaning of each entry in the menus, follow the manual structure LockIn starting with the...
Page 20: Rear Panel
3.1.4 R ANEL The back side panel provides 8 x BNC connectors for the internal A/D converters (-10 V .. 10 V) “Aux In” 4 x BNC for displaying the selected channels scaled as analogue outputs (DACs) “Display” 4 x BNC for Aux Out DACs “Out” 2 x BNC Ref-In connector for the reference input (“Ref In 1”...
Page 21 [ Setup / Beep ] Note: If the Beep function is enabled, the instrument beeps every time it detects an input overflow. Input Coupling [ LockIn / Input / Couple ] If the specification of the instrument allows it, this option switches between coupled input and coupled input.
Page 22 other. Tau1 In both entries , one can chose between a time ( 0.1 ms, 0.2 ms, ... 500 s , 1 ks ) and a kind of frequency related integration ( 10/f 100/f ). The later still uses the Butterworth filter, but chooses the closest time constant for the currently selected frequency during spectra acquisition.
Page 23: Reference Output [ Lockin / Ref ]
R oll-Off or Slope [ LockIn / Input / Slope ] This parameter is related to the order of the low pass filter. We can select among 6 dB/oct, 12 dB/oct and 24 dB/oct. The 6 dB/oct selection equals a low pass filter slope of 1 order, while the 12 dB/oct and 24 dB/oct equal the 2 and 4...
Page 24: Display Settings [ Lockin / Display ]
Reference Output Phase [ LockIn / Ref / Phase ] → phase Phase stands for the phase shift between the periodic excitation provided from the reference output or, in PLL mode, from the external trigger source and the detected oscillation at the input. In case the harmonic is equal to one, the number defined here is the phase difference between the reference output signal and the signal that is multiplied with the lock-in...
Page 25: Aux Out [ Lockin / Out ]
“no signal”. C hannel [ LockIn / Display / Channel ] In order to change the settings of the four channels, this button realizes the channel selection. All selections displayed in Group, are valid on the selected Type Range channel only. Group of Displayed Signal [ LockIn / Display / Group ] The large amount of possible input signals is organized in Groups:...
Page 26: The Spectra Menu [Spectra]
AUX Out Value [ LockIn / Out / Value] For the channels 5 to 8, a value given in V can be set here. In the remote control regime, this function can be used to control external parameters of a set-up and thus to program more enhanced measurement procedures.
Page 27: Acquire [ Spectra / Acquire ]
Color [ Spectra / Display / Color ] Color This menu item shows the color of the selected axis. If the then the channel is not displayed. This menu item does not exist if the selected axis is freq Offset [ Spectra / Display / Offset ] This shifts the selected curve along its axis.
Page 28: Save [ Spectra / Save ]
time constant (see 3.2.1). In order to check useful values with respect to the settle time, refer to the table on page 22. 3.3.4 S PECTRA After the acquisition process finished, data can be saved to the hard disk or the USB flash drive for later analysis.
Page 29: Display [ Scope / Display ]
Stop entry displays as instruction. 3.4.2 D ISPLAY COPE ISPLAY The display screen of the oscillo scope works like the display of the Spectra mode. All measured data are superimposed on each other. auto auto The scale can be fixed or .
Page 30: Setup [ Setup ]
Knob curve with the . Notice that the reference frequency shifts together with the cursor [LockIn] position. When you go back to , the selected frequency is kept and you can change time constant or excitation amplitude. In addition, the Q-factor of detected resonances is calculated and displayed. You have measured a resonance curve in spectra mode.
Page 31: Handling Of Parameter Settings
and plug it into the front panel USB connector. Click on the button to start Update the update. The main screen will display messages about the updated files and the update success. To activate the new files switch the device off, wait a second and switch on again.
Page 32: Known Problems
User name: long Password: 3.10 K NOWN ROBLEMS One error might occur if USB flash drives are used. This error is caused by a problem in the linux operation system. It is not able to mount all types of USB flash drives. When a certain type was mounted, mounting another type might require a restart of the eLockIn 32 (58)
Page 33: Remote Control
4 REMOTE CONTROL – Controlling your eLockIn via network – 4.1 G CGI- I ENERAL CCESSING VIA NTERFACE Communication between the remote computer and the eLockIn is based on TCP (Transmission Control Protocol) and http (Hypertext Transfer Protocol) for transferring HTML files and pictures.
Page 34: Sending Key Codes To The Elockin
eLockIn Before the can be remote-controlled, the user has to provide a user name eLockIn and a password. This can either be done by entering the 's IP address in a /cgi-bin/login.cgi web browser and filling in the authorization form, or by calling directly.
Page 35 Key (char) ASCII Code Action Enter LockIn menu Enter Spectra menu Enter Scope menu Enter Measure menu Enter Setup menu These buttons invoke the action displayed next to them on the screen, depending on the current position in the menu tree. Go back in menu Down Left...
Page 36: Setting Any Values
Figure 12: Keys and corresponding buttons 4.1.4 S ETTIN G ALUES eLockIn At some menu positions, the require special numerical values which correspond to the values that will be set. The following tables show the respective numbers/values at different menu positions. Number Value Number...
Page 37 Number Value Number Value “Off” 0 or 1 harmonic harmonic ‫׃‬ ‫׃‬ harmonic ‫׃‬ ‫׃‬ LockIn-Ref-Harm Table 8: Menu-Entry: ‫׃‬ ‫׃‬ lockin.ini entry: Harmonic 200/f Key code: 8D1_??_ LockIn-Input- Table 6: Menu-Entry: Number Value Time-Sync lockin.ini entry: Sync0 SyncLoL RefIn = OFF These two entries in the lockin.ini file equal RefIn = ON Key code: 895D_??_...
Page 38 Color and in Number Value Scope-Display-Color 10 nV Key code: CD9_Channel_5_??_ 20 nV Number Value 50 nV Single 100 nV Conti. 200 nV Integ. 500 nV Table 14: Menu-Entry: Spectra-Acquire- Type 1 µV Key code: C59_??_ 2 µV Number Value 5 µV 0.01*T 10 µV...
Page 39 Number Value Number Value 1µV 1µs 2µV 2µs 5µV 5µs 10µV 10us 20µV 20us 50µV 50µs 100µV 100µs 200µV 200µs 500µV 500µs 10mV 10ms 20mV 20ms 50mV 50ms 100mV 100ms 200mV 200ms 500mV 500ms Table 19: Menu-Entry: Scope-Display- Channel[Time]-ScaleH Key Code: 4D9_0_D_??_ auto Scope-Display- Table 18: Menu-Entry:...
Page 40: Examples For Keycode Operation
4.1.5 E XAMPLES EYCODE PERATION The following examples are not complete at all, however, they explain the basic operation of the device through the KeyCode. Thus, even never described or new entries in the menu can be accessed by simply following a very simple schemata: the lowest entry usually is decoded as “_0_”...
Page 41: Retrieving Screenshots
Set Oscilloscope to Start Code: http://192.168.1.7/cgi-bin/remote.cgi?49_0_ Function: stops the oscilloscope screen from data acquisition. Description: 4 … enter Osci menu 9 … select Run entry inside the Misc menu _ … tells that a parameter is following 1 … equals the 2 entry in this menu which is “STOP”...
Page 42: Example Program: Lockinremote
http://192.168.1.7/setup/lockin.ini This file contains: Amplitude: 0.0200 Frequency: 1001.00 Timeconstant: 9 Rolloff: 24 InputRange: 1 Phase: 10.0 Harmonic: 1 AmplCaretPos: 3 FreqCaretPos: 4 FreqCaretPosTail: 2 PhaseCaretPos: 5 DisplayChannel: 2 Channel1Type: 3 Channel1Range: 120 Channel2Type: 4 Channel2Range: 7 Channel3Type: 26 Channel3Range: 120 Channel4Type: 27 Channel4Range: 7 InputCouple: 0...
Page 43 LockInRemote uses a TClientSocket object to set up a TCP connection to the eLockIn , working in non-blocking mode. After starting the program, the screen will still be empty, because authentication is required first. Click LockIn→Authenticate to open the authentication menu. Enter eLockIn your user name, password and the 's IP and click 'Connect'.
Page 44: Use Cgi-Functions Via Web Browser
'LockIn' menu. Enter parameters/values as described above (no underscores needed here!). 4.2 U CGI-F UNCTIONS VIA ROWSER eLockIn Web browsers are also able to address the CGI-interface of the directly. The commands are based on the structure described in the previous chapter. The only eLockIn difference is that the web browser needs the IP-address of the for every...
Page 45: Remote By Matlab
_SetLockInFilterSlop Filter Slope Return Switches the roll-off of the filter. The type: value. values are coded as in table 4 double on page 36 _SetLockInUac Return Sets the amplitude of the reference type: value. output to a values given as double. double _SetLockInFreq Frequency...
Page 46: Remote Control For The Elockin In Labview
void _Init (char* IPasText); double _GetLockInData (long Channel); void _SendKeyCode (char* Text); For the DLL Version 1.0.0.5, these functions have been tested to operate well with MatLab. Note that parameters given as “double” are requested to be provided as floating point number in Matlab, even if the number is an integer. IMPORTANT NOTE: the function “_Init”...
Page 47 phase offset tcpip_settings.vi reads the lockin.ini via a TCP-IP connection • „TCP Open Connection“ == „TCP Verbindung öffnen“ inputs: IP address of the eLockIn device --> purple --> 192.168.1.7 Communication port --> blue --> 80 outputs: Connection ID output --> thin green Error Output (Fehlerausgang) -->...
Page 48: Dll Based Access By Labview
Result for „GET /setup/lockin.ini CR CR“ 4.5.2 DLL BASED ACCESS eLockin.vi hierarchie The main program eLockin.vi contains a sequence in three steps and calls two sub-VI's: Ref_eLockin.vi and Get_eLockin.vi. During run, it calls a three-step sequence: Step 0: eLockin.vi starts the communication ●...
Page 49 TestAuxOut.vi This is an additional example program, which shows how to use the function „_SetLockInAuxOut“. The number taken as „Channel“ are counted from zero, while the labeling at the backside of the instrument count the AuxOut-Pins from One. Therefore, the 5 output named „DA5“...
Page 50: Software-Update
5 SOFTWARE-UPDATE eLockIn CAUTION: The software update of the can be compared with a BIOS update of a PC. One should spare the same caution. A power failure or power blackout eLockIn during this procedure might cause a system crash, after which the software needs to be restored in our facilities.
Page 51: Revision History
6 REVISION HISTORY 6.1 M ANUAL EVISIONS This Manual is dated 11/14/14. 6.2 H ARDWARE EVISIONS The current hardware revision is: 29 6.3 S OFTWARE REVISION The current software revision is: 1.15a 51 (58)
Page 52: Appendices
7 APPENDICES 7.1 S CHEMATIC DIAGRAM OF THE SIGNAL PATHS 52 (58)
Page 53: Diagram Of The Lockin Amplification Paths
7.2 D IAGRAM OF THE LOCKIN AMPLIFICATION PATHS Diagram of the preamplifier switches. 53 (58)
Page 54: Frontpanel Dimensions
7.3 F RONTPANEL IMENSIONS 54 (58)
Page 55: Instrument Specific Test Sheets
7.4 I NSTRUMENT PECIFIC HEETS (insert with 10 pages of data) 55 (58)
Page 56: Preamplifier Connector Pinout
7.5 P REAMPLIFIER ONNECTOR INOUT 56 (58)
Page 57: Ce Certificate
Anfatec recommends Cal Interval : 12 Months Instrument Condition: new product Anfatec certifies above instrument meets or exceeds published measurement specifications and has been calibrated using standards traceable to the PRC National Institute of Metrology (NIM) and/or other National Metrology Institutes (NIST, NPL, PTB) that are linked to the international system of units (SI).
Page 58: Traceability Chart
7.7 T RACEABILITY HART 58 (58)

Anfatec eLockIn 203 Manual

1 Introduction

2 Lock-In Basics

3 Users Manual

4 Remote Control

5 Software-Update

6 Revision History

7 Appendices

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