MODEL SR850 DSP Lock-In Amplifier Stanford Research Systems 1290-D Reamwood Avenue Sunnyvale, California 94089 Phone: (408) 744-9040 • Fax: (408) 744-9049 email: info@thinkSRS.com • www.thinkSRS.com Copyright © 1992 by SRS, Inc. All Rights Reserved. Revision 2.
TABLE OF CONTENTS GENERAL INFORMATION Safety and Preparation for Use Specifications Abridged Command List 1-3 1-5 1-7 GETTING STARTED Your First Measurements The Basic Lock-in Displays and Traces Outputs, Offsets and Expands Scans and Sweeps Using the Disk Drive Aux Outputs and Inputs Trace Math 2-1 2-3 2-7 2-13 2-17 2-23 2-31 2-35 SR850 BASICS What is a Lock-in Amplifier? What Does a Lock-in Measure? The SR850 Functional Diagram Reference Channel Phase Sensitive Detectors Time Constants and DC Gain DC
Table of Contents Interface Ready and Status GET (Group Execute Trigger) 6-2 6-2 DETAILED COMMAND LIST Reference and Phase Input and Filter Gain and Time Constant Output and Offset Trace and Scan Display and Scale Cursor Mark Aux Input and Output Math Store and Recall Setup Print and Plot Front Panel and Auto Functions Data Transfer Interface Status Reporting 6-3 6-4 6-6 6-7 6-9 6-10 6-11 6-13 6-14 6-15 6-16 6-18 6-19 6-21 6-22 6-23 6-28 6-29 STATUS BYTE DEFINITIONS Serial Poll Status Byte Service Reque
SAFETY AND PREPARATION FOR USE WARNING Dangerous voltages, capable of causing injury or death, are present in this instrument. Use extreme caution whenever the instrument covers are removed. Do not remove the covers while the unit is plugged into a live outlet. CAUTION outlet which has a properly connected protective ground. This instrument may be damaged if operated with the LINE VOLTAGE SELECTOR set for the wrong AC line voltage or if the wrong fuse is installed.
1-4
SR850 DSP LOCK-IN AMPLIFIER SPECIFICATIONS SIGNAL CHANNEL Voltage Inputs Current Input Full Scale Sensitivity Input Impedance Gain Accuracy Input Noise Signal Filters CMRR Dynamic Reserve Harmonic Distortion REFERENCE CHANNEL Frequency Range Reference Input Phase Resolution Absolute Phase Error Relative Phase Error Orthogonality Phase Noise Phase Drift Harmonic Detect Acquisition Time DEMODULATOR Zero Stability Time Constants Harmonic Rejection INTERNAL OSCILLATOR Frequency Frequency Accuracy Frequency Res
SR850 DSP Lock-In Amplifier INPUTS AND OUTPUTS Channel 1 Output Channel 2 Output X and Y Outputs Aux. Outputs Aux. Inputs Trigger Input Monitor Output DISPLAYS Screen Format Displayed Quantities Display Types Chart Data Buffer ANALYSIS FUNCTIONS Smoothing Curve Fits Calculator Statistics GENERAL Monitor Interfaces Preamp Power Hardcopy Disk Power Dimensions Weight Warranty X, R, θ, or Trace 1-4.
SR850 DSP Lock-In Amplifier COMMAND LIST VARIABLES i,j,k,l,m f x,y,z s REFERENCE and PHASE PHAS (?) {x} FMOD (?) {i} FREQ (?) {f} SWPT (?) {i} SLLM (?) {f} SULM (?) {f} RSLP (?) {i} HARM (?) {i} SLVL (?) {x} page 6-4 6-4 6-4 6-4 6-4 6-4 6-4 6-5 6-5 description Set (Query) the Phase Shift to x degrees. Set (Query) the Reference Source to Internal (0), Sweep (1) , or External (2). Set (Query) the Reference Frequency to f Hz.Set only in Internal reference mode.
SR850 DSP Lock-In Amplifier DTRC (?) i {, j} DSCL (?) {x} DOFF (?) {x} DHZS (?) {i} 6-11 6-11 6-11 6-12 RBIN? i 6-12 Set (Query) theFull (i=0), Top (i=1) or Bottom (i=2) Display Trace to trace j (1,2,3,4). Set (Query) theFull (i=0), Top (i=1) or Bottom (i=2) Display Range to x. Set (Query) theFull (i=0), Top (i=1) or Bottom (i=2) Display Center value to x. Set (Query) theFull (i=0), Top (i=1) or Bottom (i=2) Display Horizontal Scale to 2 ms (0) through 200 ks (32) per div.
SR850 DSP Lock-In Amplifier RDAT RSET 6-18 6-18 Recall the Trace Data from the file specified by FNAM to the active display's trace buffer. Recall the Settings from the file specified by FNAM.
SR850 DSP Lock-In Amplifier INTERFACE *RST *IDN? LOCL(?) {i} OVRM (?) {i} TRIG page 6-26 6-26 6-26 6-26 6-26 STATUS *CLS *ESE (?) {i} {,j} page description 6-27 Clear all status bytes. 6-27 Set (Query) the Standard Event Status Byte Enable Register to the decimal value i (0-255). *ESE i,j sets bit i (0-7) to j (0 or 1). *ESE? queries the byte. *ESE?i queries only bit i. 6-27 Query the Standard Event Status Byte. If i is included, only bit i is queried.
GETTING STARTED YOUR FIRST MEASUREMENTS The sample measurements described in this section are designed to acquaint the first time user with the SR850 DSP Lock-In Amplifier. Do not be concerned that your measurements do not exactly agree with these exercises. The focus of these measurement exercises is to learn how to use the instrument. It is highly recommended that the first time user step through some or all of these exercises before attempting to perform an actual experiment.
Getting Started 2-2
The Basic Lock-in THE BASIC LOCK-IN This measurement is designed to use the internal oscillator to explore some of the basic lock-in functions. You will need BNC cables. Specifically, you will measure the amplitude of the Sine Out at various frequencies, sensitivities, time constants and phase shifts. The "normal" lock-in display will be used throughout this exercise. 1. Disconnect all cables from the lock-in. Turn the power on while holding down the [←] (backspace) key.
The Basic Lock-in 5. Press the softkey. This adds 90° to the reference phase shift. The value of X drops to zero and Y becomes minus the magnitude (-1.000 V). Press the softkey. Highlight the phase shift. Use the knob to adjust the phase shift until Y is zero and X is equal to the positive amplitude. The knob can be used to adjust parameters which are continuous, such as phase, amplitude and frequency. The final phase value should be close to zero again.
The Basic Lock-in that the measured magnitude (R) is a sizable percentage of full scale. 9. Press Highlight the full scale sensitivity. Use the knob to change the sensitivity to 50 mV. Parameters which are discrete values, such as sensitivity and time constant, can only be changed with the knob. Numeric entry is not allowed for these parameters. Change the sensitivity back to 20 mV. 10. Press
The Basic Lock-in 13. Press [GAIN/TC] Press to select <200 Hz. Display the Gain and Time Constant menu again. This turns on synchronous filtering whenever the detection frequency is below 200 Hz. Synchronous filtering effectively removes output components at multiples of the detection frequency. At low frequencies, this filter is a very effective way to remove 2f without requiring extremely long time constants.
Displays and Traces DISPLAYS and TRACES This measurement is designed to use the internal oscillator and an external signal source to explore some of the display types. You will need a synthesized function generator capable of providing a 100 mVrms sine wave at 1.000 kHz (the DS345 from SRS will suffice), BNC cables and a terminator appropriate for the generator function output.
Displays and Traces Press Highlight the internal oscillator frequency. Use the knob to change the frequency to 999.80 Hz. By setting the lock-in reference 0.2 Hz away from the signal frequency, the X and Y outputs are 0.2 Hz sine waves (difference between reference and signal frequency). The X and Y output displays should now oscillate at about 0.2 Hz (the accuracy is determined by the crystals of the generator and the lock-in). 4.
Displays and Traces Press [AUTO SCALE] [AUTO SCALE] automatically scales the active display. In this case, the trace data is moving and autoscaling may not do a very satisfactory job. Press the <± Range> softkey. This is the fifth softkey from the top. To manually set the graph scale, you set the range (±) and center value (@). The graph displays a scale equal to the center value plus and minus the range. Press [1] [8] [0] [ENTER] In this case, set the bar graph to ±180°.
Displays and Traces Press to select Rising Edge. With a TTL reference signal, the slope needs to be set to either rising or falling edge. The signal vector on the polar graph will not rotate since the phase is a constant. The actual phase depends upon the phase difference between the function output and the sync output from the generator. The external reference frequency (as measured by the lock-in) is displayed at the bottom of the screen.
Displays and Traces Using the keypad, enter a phase shift which is 45° greater than the displayed phase shift. At a measured phase shift of 45°, trace 3 should equal cos45° or 0.707. This concludes this measurement example. You should have a feeling for the basic operation of the display types and trace definitions.
Displays and Traces 2-12
Outputs, Offsets and Expands OUTPUTS, OFFSETS and EXPANDS This measurement is designed to use the internal oscillator to explore some of the basic lock-in outputs. You will need BNC cables and a digital voltmeter (DVM). Specifically, you will measure the amplitude of the Sine Out and provide analog outputs proportional to the measurement. The effect of offsets and expands on the displayed values and the analog outputs will be explored. 1. Disconnect all cables from the lock-in.
Outputs, Offsets and Expands 4. Press [REF/PHASE] Display the Reference and Phase menu. Press Highlight the sine output amplitude. Press [.] [5] [ENTER] Enter an amplitude of 0.5 V. The top display should show X=0.5 V and the CH1 output should be 5 V on the DVM. 5. Press [OUTPUT/OFFSET] Display the Output and Offset menu. This menu chooses which measured parameters or traces are output on CH1 and CH2. In addition, the X, Y and R offsets and expands are programmed in this menu.
Outputs, Offsets and Expands The highlighted EXPD indicator turns on at the bottom left of the top display to indicate that the displayed trace is affected by an expand. The CH1 output is (X/Sensitivity - Offset)xExpandx10V. In this case, the output voltage is CH1 Out = (0.5/1.0 - 0.4)x10x10V = 10V The expand allows the output gain to be increased by up to 256. The output voltage is limited to 10.
Outputs, Offsets and Expands should be 5.0 V. Press Highlight the CH1 source. The CH1 output is proportional to this source. Use the knob to select Trace1. CH1 can be proportional to X, R, θ, or Trace 1-4. Choose Trace 1. Trace 1 has a default definition of X so the CH1 output should remain 5.0 V (but its bandwidth is only 200 Hz instead of 100 kHz). 8. Press [TRACE/SCAN] Display the Trace and Scan menu. Traces are defined as A•B/C.
Scans and Sweeps SCANS and SWEEPS This measurement is designed to use the internal oscillator to explore some of the basic lock-in functions. You will need BNC cables. Specifically, you will measure the response of the line notch filters by sweeping the internal reference frequency and measuring the sine output. Traces and strip chart displays will be used to record X, Y, R and θ as the signal is swept through the input notch filters. 1. Disconnect all cables from the lock-in.
Scans and Sweeps 4. Press [DISPLAY/SCALE] Display the Display and Scale menu. This menu configures and scales the different screen displays and graphs. Press the softkey to select the Trace number. Highlight the trace number for the Top Bar graph. The SR850 acquires and displays data in the form of traces. The default definitions for the 4 traces are X, Y, R and θ. These definitions may be changed. Use the knob to select Trace 3. Display the magnitude R (Trace 3) on the top graph. 5.
Scans and Sweeps sets the amount of time the buffer will store and the length of any sweep. In this measurement, let's leave the trace definitions equal to the defaults and just change the sample rate and scan time. Press Highlight the sample rate. Use the knob to select 32 Hz. The trace data will be sampled at 32 Hz and stored in the buffer. After each data point is recorded, the reference frequency will be updated. This determines the resolution of our data along the time axis.
Scans and Sweeps 10. Press [DISPLAY/SCALE] Display the Display and Scale menu. Press to select Single. Choose a full screen display. Press Highlight the display type (the default is polar). Use the knob to select Chart. Let's view the stored data on a chart graph. Press again to highlight the Trace number. Use the knob to select Trace 3. To view R on the chart, you need to display Trace 3. The chart now displays R vs time (frequency).
Scans and Sweeps quency of each point is displayed in the cursor coordinate display. The graph shows all 3200 data points at once. Since the screen resolution only has 640 pixels across, each X-axis value must represent multiple data points. The cursor reads the Max, Min or Mean of the data points graphed at each X-axis position. Press to select Min. To read the notch filter minimum frequencies, select Min. Use the knob to read the frequencies of the notch filter zeroes or minimums.
Scans and Sweeps looping (Loop). In the loop mode, scans repeat indefinitely and the entire data buffer is filled at the sample rate. When the end is reached, new points are added at the beginning again, overwriting the oldest data. This mode is convenient for always storing the last buffer full of data. If something worth saving occurs, simply pause the scan and save, print or plot the data. 16. When the scan is complete, press [TRACE/SCAN]. Display the Trace and Scan menu.
The Disk Drive USING THE DISK DRIVE The disk drive on the SR850 may be used to store 3 types of files. 1. Data File This includes the data in the active display trace. In addition to the data, the instrument state (sensitivity, input configuration, time constant, reference, scan parameters, aux outputs) and the trace definition of the stored trace are saved. Data files are recalled into the trace buffer of the active display.
The Disk Drive ence set at 1.000 kHz. The reference mode (Intrnl) and frequency are displayed at the bottom of the screen. In this mode, the lock-in generates a synchronous sine output at the internal reference frequency. The sine amplitude is 1.000 Vrms and the sensitivity is 1 V(rms). Since the phase shift of the sine output is very close to zero, the upper display (X) should read close to 1.000 V and the lower display (Y) should read close to 0.000 V. 3.
The Disk Drive 8. Press [DISK] Display the Disk menu. Press Choose Disk Utilities. Press Make sure that the disk does not contain any information that you want. Formatting the disk takes about a minute. Press Go back to the main Store and Recall menu. Press Display the Data Save menu. Press Now we need a file name. Press [ALT] [ALT] lets you enter the letter characters printed below each key. The numbers function as normal.
The Disk Drive Press Save Trace 2. 11. Press to select On. Display the disk catalog. This display lists all of the files on the disk. The files which you just saved should appear in the catalog. Each file has a name, extension, and type. The file type for binary trace data is TRC. Press Go back to the main Store and Recall menu. 12. Press [PAUSE RESET] Reset the scan. This clears the data buffers within the lock-in. 13.
The Disk Drive Use the knob to select the Chart display. Display two charts. Press to select Bottom. Select the bottom display. The bottom display type should be highlighted. Use the knob to select the Chart display for the bottom display. Both displays should be charts. Press [AUTO SCALE] Auto scale the bottom display. The [AUTO SCALE] will scale the active display. In this case, the bottom display is active since we just changed it.
The Disk Drive Press This recalls the data file from disk and stores it in the active display trace. The active display trace is redefined to agree with the recalled data trace definition. In this case, the data is recalled into Trace 1 (since it is currently being shown on the active display). Trace 1 becomes defined as Y since that is the trace definition of the recalled data. The existing data in Trace 2 (bottom display) is not changed. Press [AUTO SCALE] Auto Scale the top display.
The Disk Drive STORING AND RECALLING SETTINGS 1. Turn the lock-in on while holding down the [←] (backspace) key. Wait until the power-on tests are completed. Disconnect any cables from the lock-in. When the power is turned on with the backspace key depressed, the lock-in returns to its default settings. See the Default Settings list in the Menu section for a complete listing of the settings. Change the lock-in setup so that we have a nondefault setup to save. 2.
The Disk Drive Press Display the disk catalog listing. Note that settings files have the file type SET. Use the knob to select the settings file which you just saved. When the disk catalog is displayed, the knob highlights a file. Use the knob to choose the file TEST1 to recall. 6. Press This recalls the settings from the file TEST1. The lock-in settings are changed to those stored in TEST1.
Aux Outputs and Inputs AUX OUTPUTS and INPUTS This measurement is designed to illustrate the use of the Aux Outputs and Inputs on the rear panel. You will need BNC cables and a digital voltmeter (DVM). Specifically, you will set the Aux Output voltages and measure them with the DVM. These outputs will then be connected to the Aux Inputs to simulate external DC voltages which the lock-in can measure. 1. Disconnect all cables from the lock-in. Turn the power on while holding down the [←] (backspace) key.
Aux Outputs and Inputs 5. Disconnect the DVM from Aux Out 1. Connect Aux Out 1 to Aux In 1 on the rear panel. The A1 monitor should now display -5 V. The monitor display shows all 4 Aux Inputs. To display and save the Aux Input values, a trace needs to be defined to measure an Aux Input. 6. Press [TRACE/SCAN] Display the Trace and Scan menu. Press the second softkey, next to the trace definition, to highlight the X. Trace 1 is defined as X. Let's change it to Aux Input 1.
Aux Outputs and Inputs 1 V to 5 V in 100 seconds updating every second. The output voltage is measured on Aux In 1, recorded in Trace 1 and displayed on the top graph. 10. Press [DISPLAY/SCALE] Show the Display and Scale menu. Press to highlight the type of the top display. The top display is a bar graph. Let's change it to a chart to show the history of Aux In 1. Use the knob to change the display type to Chart. The chart display shows the history of the sweep.
Aux Outputs and Inputs 2-34
Trace Math TRACE MATH This example is designed to familiarize the user with the trace math functions in the lock-in. You will need BNC cables and a 50Ω terminator. Specifically, you will record the input noise in a trace and perform various calculations with the trace. The internal oscillator will also be used to provide signal data for curve fits. There are a few points to remember about the trace math functions.
Trace Math Use the knob to select 50 nV. To measure the input noise, we need to use an appropriate sensitivity. 4. Press [TRACE/SCAN] Display the Trace and Scan menu. Press Since the time constant is 100 ms, we need a sample rate greater than 1 Hz to record the output. Use the knob to change the sample rate to 16 Hz. Choose 16 Hz as the sample rate. Leave the scan mode on Loop. Data will be recorded indefinitely with the trace buffer storing the last 16k (1000 seconds) of data. 5.
Trace Math and right edge of the graph display. In this case, 50 seconds of data (800 data points at 16 Hz sample rate). The results are displayed at the bottom of the screen. The standard deviation (σ)should be about 6 nV or so. This is the rms noise of the input in a noise equivalent bandwidth of 1.2 Hz (100 ms, 12 dB/oct time constant). The input noise (in Volts/ √Hz) is thus the standard deviation divided by the square root of 1.2 Hz.
Trace Math Press The net effect is to take the absolute value of X. Let the calculation finish. Press [AUTO SCALE] The magnitude of the data is back to 10 -9. Use the knob to select log10. Take the log of |X|. Press Let the calculation finish. Use the knob to select ❊. Let's multiply the data by something. Press to select Constant. Multiply the data by a constant. Press Highlight the constant value. Press [2] [0] [ENTER] Enter 20.
Trace Math Press <1 Shot/Loop> to select 1 Shot. Stop data acquisition after the scan is complete. 13. Connect the Sine Out to the A input using a BNC cable. The input impedance of the lock-in is 10 MΩ. The Sine Out has an output impedance of 50Ω. Since the Sine Output amplitude is specified into a high impedance load, the output impedance does not affect the amplitude. Wait until the value of X reaches 1 V. The sine amplitude is 1.000 Vrms and the sensitivity is 1 V(rms).
Trace Math Press Set the left limit of the region at the start of the signal decay. Use the knob to position the cursor 3 divisions to the right of the left limit. Select the smallest region which covers the signal decay. Press Set the right limit. Move the cursor farther to the right. The fit region is between the two limit marks (vertical heavy dashed lines). Only the data between the limits is used to calculate the fit.
Trace Math Move the cursor past the left edge of the graph to pan the data window until the signal decay becomes visible again. Scroll the data to show the signal decay region. 20. Press [MATH] Go back to the Math menu. Press Choose the Fit menu. Press View the most recent fit. The most recent fit is stored in memory and can be viewed again. Press any key to continue. Remove the parameter window so that the plotted fit can be seen.
Trace Math 2-42
SR850 BASICS WHAT IS A LOCK-IN AMPLIFIER? Lock-in amplifiers are used to detect and measure very small AC signals - all the way down to a few nanovolts! Accurate measurements may be made even when the small signal is obscured by noise sources many thousands of times larger. experiment at the reference frequency. In the diagram below, the reference signal is a square wave at frequency ωr. This might be the sync output from a function generator.
SR850 Basics This is a very nice signal - it is a DC signal proportional to the signal amplitude. sync) which is always phase-locked to the reference oscillator. Narrow band detection Magnitude and phase Now suppose the input is made up of signal plus noise. The PSD and low pass filter only detect signals whose frequencies are very close to the lockin reference frequency.
SR850 Basics WHAT DOES A LOCK-IN MEASURE? So what exactly does the SR850 measure?Fourier's theorem basically states that any input signal can be represented as the sum of many, many sine waves of differing amplitudes, frequencies and phases. This is generally considered as representing the signal in the "frequency domain". Normal oscilloscopes display the signal in the "time domain".
SR850 Basics 3-4
SR850 Basics THE FUNCTIONAL SR850 The functional block diagram of the SR850 DSP Lock-In Amplifier is shown below. The functions in the gray area are handled by the digital signal processor (DSP). We'll discuss the DSP aspects of the SR850 as they come up in each functional block description.
SR850 Basics 3-6
SR850 Basics REFERENCE CHANNEL A lock-in amplifier requires a reference oscillator phase-locked to the signal frequency. In general, this is accomplished by phase-locking an internal oscillator to an externally provided reference signal. This reference signal usually comes from the signal source which is providing the excitation to the experiment. oscillator sine wave is phase-locked to the reference. The rising zero crossing is locked to the detected reference zero crossing or edge.
SR850 Basics Harmonic Detection degrees of noise. This shows up at the output as noise in phase or quadrature measurements. It is possible to compute the two PSD reference sine waves at a multiple of the internal oscillator frequency. In this case, the lock-in detects signals at Nxfref which are synchronous with the reference. The SINE OUT frequency is not affected. The SR850 can detect at any harmonic up to N=32767 as long as Nxfref does not exceed 102 kHz.
SR850 Basics THE PHASE SENSITIVE DETECTORS (PSD's) The SR850 multiplies the signal with the reference sine waves digitally. The amplified signal is converted to digital form using a 16 bit A/D converter sampling at 256 kHz. The A/D converter is preceded by a 102 kHz anti-aliasing filter to prevent higher frequency inputs from aliasing below 102 kHz. The signal amplifier and filters will be discussed later. scale signal, the analog PSD measures the signal with an error.
SR850 Basics 3-10
SR850 Basics TIME CONSTANTS and DC GAIN Remember, the output of the PSD contains many signals. Most of the output signals have frequencies which are either the sum or difference between an input signal frequency and the reference frequency. Only the component of the input signal whose frequency is exactly equal to the reference frequency will result in a DC output. 12 dB/oct. This limitation is usually due to space and expense. Each filter needs to have many different time constant settings.
SR850 Basics need to be at 0.001 Hz! is one of the reasons why analog lock-ins do not perform well at very high dynamic reserve. In the SR850, synchronous filters are available at detection frequencies below 200 Hz. At higher frequencies, the filters are not required (2F is easily removed without using long time constants). Below 200 Hz, the synchronous filter follows either one or two stages of normal filters. The output of the synchronous filter is followed by two more stages of normal filters.
SR850 Basics DC OUTPUTS and SCALING The SR850 has X and Y outputs on the rear panel and Channel 1 and 2 (CH1 and CH2) outputs on the front panel. output proportional to simply X, Y or R. This is the output scale for the X and Y rear panel outputs as well as the CH1 and CH2 outputs when configured to output X, Y or R. When the CH1 or CH2 outputs are proportional to a data trace which is simply defined as X, Y or R, the output scale is also 10 V full scale.
SR850 Basics deviations can be expanded up to 100 times before they exceed full scale (at 1 mV sensitivity). example, if a trace is defined as X•θ/Aux 1 and X=1 mV, θ=37°, and Aux 1= 2.34 V, then the trace value is 0.001 x 37/2.34 Volt•degrees per Volt or 0.01581 Vdeg/V. This value is not changed by the sensitivity (X is the input signal, not the output voltage) or by X expand. An X offset will, however, change the value of this trace.
SR850 Basics output voltages of X, Y or R in trace output calculations. For example, a trace which is defined as X and output through CH1 or CH2 increases its output voltage by the expand factor when X is expanded. This is because the output voltage of X is expanded. The output voltage scales for the individual quantities are listed below.
SR850 Basics 3-16
SR850 Basics DYNAMIC RESERVE We've mentioned dynamic reserve quite a bit in the preceding discussions. It's time to clarify dynamic reserve a bit. high gain and low frequency noise and offset drift at the PSD output or the DC amplifier input will be amplified and appear large at the output. The noise is more tolerable than the DC drift errors since increasing the time constant will attenuate the noise.
SR850 Basics frequencies than within the operating range. While this may be a nice specification, removing noise at frequencies very far from the reference does not require a lock-in amplifier. Lock-ins are used when there is noise at frequencies near the signal. Thus, the dynamic reserve for noise within the operating range is more important. decrease and the output noise will decrease also. In general, do not run with more reserve than necessary.
SR850 Basics SIGNAL INPUT AMPLIFIER and FILTERS A lock-in can measure signals as small as a few nanovolts. A low noise signal amplifier is required to boost the signal to a level where the A/D converter can digitize the signal without degrading the signal to noise. The analog gain in the SR850 ranges from roughly 7 to 1000. As discussed previously, higher gains do not improve signal to noise and are not necessary. lock-in will measure the input noise with an ENBW of 2.5 Hz. This translates to 7.
SR850 Basics measurements in the vicinity of the notch frequencies. These filters have a finite range of attenuation, generally 10 Hz or so. Thus, if the lock-in is making measurements at 70 Hz, do not use the 60 Hz notch filter! The signal will be attenuated and the measurement will be in error. When measuring phase shifts, these filters can affect phase measurements up to an octave away. Anti-aliasing filter After all of the signal filtering and amplification, there is an anti-aliasing filter.
SR850 Basics INPUT CONNECTIONS Differential Voltage Connection (A-B) In order to achieve the best accuracy for a given measurement, care must be taken to minimize the various noise sources which can be found in the laboratory. With intrinsic noise (Johnson noise, 1/f noise or input noise), the experiment or detector must be designed with these noise sources in mind. These noise sources are present regardless of the input connections.
SR850 Basics Current Input (I) AC vs DC Coupling The current input on the SR850 uses the A input BNC. Voltage or current input is chosen in the INPUT menu. The current input has a 1 kΩ input impedance and a current gain of either 106 or 108 Volts/Amp. Currents from 1 µA down to 2 fA full scale can be measured. The signal input can be either AC or DC coupled. The AC coupling high pass filter passes signals above 160 mHz (0.16 Hz) and attenuates signals at lower frequencies.
SR850 Basics INTRINSIC (RANDOM) NOISE SOURCES Random noise finds its way into experiments in a variety of ways. Good experimental design can reduce these noise sources and improve the measurement stability and accuracy. amount of broadband noise that will be amplified. This affects the dynamic reserve. The time constant sets the amount of noise which will be measured at the reference frequency. See the SIGNAL INPUT AMPLIFIER discussion for more information about Johnson noise.
SR850 Basics 3-24
SR850 Basics EXTERNAL NOISE SOURCES In addition to the intrinsic noise sources discussed in the previously, there are a variety of external noise sources within the laboratory. For example, if the noise source is a power circuit, then f = 60 Hz and V noise = 120 V. Cstray can be estimated using a parallel plate equivalent capacitor. If the capacitance is roughly an area of 1 cm2 at a separated by 10 cm, then Cstray is 0.009 pF. The resulting noise current will be 400 pA (at 60 Hz).
SR850 Basics Microphonics Cures for inductively coupled noise include: Not all sources of noise are electrical in origin. Mechanical noise can be translated into electrical noise by microphonic effects. Physical changes in the experiment or cables (due to vibrations for example) can result in electrical noise over the entire frequency range of the lock-in. 1) Removing or turning off the interfering noise source.
SR850 Basics NOISE MEASUREMENTS Lock-in amplifiers can be used to measure noise. Noise measurements are generally used to characterize components and detectors. moving average of X is computed. This is the mean value of X over some past history. The present mean value of X is subtracted from the present value of X to find the deviation of X from the mean. Finally, the moving average of the absolute value of the deviations is calculated. This calculation is called the mean average deviation or MAD.
SR850 Basics Which method you use depends upon the requirements of the experiment. R noise The quantity Rn can be somewhat hard to understand. For example, suppose X and Y are equally noisy and centered about zero. The values of R are always positive (magnitude) and thus average to a nonzero value. In this case, X and Y noise result in an average R which can be interpreted as the minimum detectable value of R.
FRONT PANEL Brightness Control Soft Keys Spin Knob Key Pad CONTROL MODEL SR850 DSP LOCK-IN AMPLIFIER START CONT PAUSE RESET A SYSTEM CURSOR B Disk Drive ACTIVE DISPLAY C PRINT E 8 9 MARK 6 EDIT MARK REF PHASE G 5 4 1 AUTO RESERVE AUTO GAIN P AUTO PHASE 2 _ ALT Power Button Video Display 50 Ω X MATH T SYSTEM SETUP Y Z SIGNAL IN CH2 <20mA O S DISK OUTPUT SINE OUT L DISPLAY SCALE N AUX OUTPUTS ENTER W CH1 1M Ω CURSOR MAX/MIN EXP V REFERENCE IN STANFORD RESEARC
Front Panel The main area of the display is occupied by the output display(s). Both single and dual trace displays are available. In addition, each display can be formatted as a large numeric readout with bar graph, a polar graph, or a strip chart. In these cases, the knob function is selected by the soft keys. The [CURSOR] key, which can be pressed at any time, will set the knob function to scrolling the cursor if there is a strip chart displayed.
Front Panel Ch1 & Ch2 Outputs The Channel 1 and Channel 2 outputs can be configured to output a voltage from -10 V to +10 V proportional to X, Y, R, θ, or Traces 1 through 4. ±10 V is full scale. The outputs can source 10 mA maximum. Signal Inputs The input mode may be single-ended, A, or differential, A-B. The A and B inputs are voltage inputs with 10 MΩ, 25 pF input impedance. Their connector shields are isolated from the chassis by 10 Ω (Ground) or 1 kΩ (Float).
Front Panel 4-4
SCREEN DISPLAY Soft Key Definitions. Pressing the corresponding soft key will either highlight a field or select an option. Lock-in Parameters Sensitivity and Dynamic Reserve Time Constant and Slope Full Scale = 10 mV Dyn Reserve = 0 dB X Trace 1 Top Display 100 mS Syncro 12 dB/oct Line 2xLin AC A X = 9.7284 mV ± 10.000 e-3 Trace 2 Bottom Display Input configuration and signal filters 0.0 Y Stop 0.0 Sensitivity 10 mV f.s. 60 dB gain Reserve Min Max Manual V Y =-1.2050 mV ± 10.
Screen Display DATA TRACES In most cases, the default trace definitions will suffice. For specialized situations, the traces may be redefined to fit the experiment. Some examples: The SR850 collects and displays data in the form of traces. There are four data traces which may be defined. Each trace is defined as A•B/C where the parameters A, B, and C are chosen from X, Y, R, θ, Xnoise, Ynoise, Rnoise, Aux Inputs 1-4, Frequency, and unity (1). C can also be any quantity squared.
Screen Display SINGLE and DUAL TRACE DISPLAYS Remember, only data traces may be displayed. The traces are defined in the TRACE/SCAN menu. The choices of which traces are displayed, and in which formats, are selected in the DISPLAY/SCALE menu. The screen can be formatted as a single trace (Single) display or a dual trace (Up/Down) display. The screen format is selected in the DISPLAY/ SCALE menu.
Screen Display 4-8
Screen Display BAR GRAPHS The most commonly used display type is the Bar graph with large numeric readout. This display most closely resembles a "normal" lock-in. The bar graph display is shown below. The bar graph only occupies half of the screen, even when the screen format is full height. Thus, it generally makes sense to use the bar graph in split screen mode and show two bar graphs. Trace Identifier Trace 1 Trace Definition X X = 9.7284 mV Full scale range ± 10.000 e-3 Offst 0.
POLAR GRAPHS The polar graph is a convenient way to view magnitude and phase. The signal is represented as a vector on an X-Y coordinate axes. The full screen polar display is shown below. The split screen polar graph is half as big. Y Axis (90°) Signal Vector X Axis (0°) Trace Offset and Expand Indicators Offst Expd Signal Vector Coherent signals have a steady phase and the signal vector will have a steady direction. Signals which are noisy will move around in direction as well as magnitude.
Screen Display STRIP CHARTS Chart displays are used to view stored traces. Only stored traces have a time history, thus, only stored traces may be displayed on a chart. The full screen chart display is shown below. If the split screen format is used, the chart will display half as many vertical divisions but will be the same as the full size display in all other aspects. Trace Identifier Trace Definition Y Trace 2 Cursor Readout 36.000 S 58.
Screen Display Data Scrolling The chart display acts like a strip chart recorder where the pen is drawing the most recent data. For example, if the sample rate is 1 Hz (1 point taken per second) and the horizontal scale is 10 S/div, then the graph displays 100 data points (10 divisions x 10 points per division). As new data is taken, the old data scrolls to the left at the rate of 10 S/div. This is because new points are added at a fixed location (right edge of the graph) just like a strip recorder.
Screen Display TRACE SCANS, SWEEPS & ALIASING Trace and Scan parameters are selected in the TRACE/SCAN menu. imum scan length is 125 seconds at 512 Hz or 12 days at 62.5 mHz (64000 points). Changing the sample rate will only change the scan length if the maximum number of data points is already being used. Otherwise, the number of data points in the scan is changed to keep the scan length constant.
Screen Display the scan length is only meaningful is parameters are being swept. Once the trace buffer has looped around, the oldest point (at any time) is at bin#0 and the most recent point is at bin#k where k is the buffer length (minus 1). The samples represent a sine wave much slower than 2 Hz that isn't actually present in the output! The chart display of this trace will show a sine wave at a very low frequency and will be rather misleading.
Screen Display SETTINGS & INPUT/OUTPUT MONITOR MENU DISPLAY The upper two lines of the screen are the monitor display (see the screen on pg. 4-5). The lock-in settings (sensitivity, time constant, etc.) or the lock-in signal measurements (X, Y, R, θ, and the Aux Inputs) may be monitored. Use the DISPLAY menu to select the type of monitor (Settings or Input/Output). The Soft Key menu boxes define the functions of the 6 soft keys to the right of the screen. The menu boxes are grouped into menus.
STATUS INDICATORS Run FILTR Ext S Fr= 100.00 Hz GPIB ERR SRQ TRIG RESRV OUTPT UNLOCK Harmonic= 1 LOC ALT OUTPT If the output (either X, Y, R or a trace output voltage) is greater than 1.09 times full scale, then OUTPT is displayed. This can occur if the sensitivity is too low or if the output is expanded such that the output voltage exceeds 10 V. Note that a trace output can overload even if it is not being displayed on the screen or output to CH1 or CH2.
Screen Display allowed), press the [HELP] key. LOC is on whenever local front panel control is allowed (usually on). SRQ This indicator is on whenever a GPIB Service Request is generated by the SR850. SRQ stays on until a serial poll is completed. ALT Indicates that the ALTERNATE keypad is in use. The ALTERNATE keypad uses the alphabetic legends printed below each key. To enter the ALT mode, press the [ALT] key once. Pressing the keys will now enter letters into the active entry field. The [0]...[9], [.
Screen Display 4-18
KEYPAD CONTROL START CONT PAUSE RESET A SYSTEM CURSOR B C D E 8 9 MARK 5 6 EDIT MARK CURSOR SETUP H AUTO RESERVE AUTO GAIN P AUTO PHASE 2 3 0 . _ K M N EXP W V REFERENCE IN SINE OUT NORMAL AND ALTERNATE KEYS CH1 The normal key definitions are printed on each key. In addition, each key also has an alternate 50 Ω 1M Ω definition printed below it. The [ALT] key toggles the keypad between the two definitions. The ALT screen indicator is on when the alternate definitions are in use.
A new phase shift may now be Phase Adjust entered using the numeric 0.000 deg. keys. For example, to set the phase shift to 12.34 degrees, press [1] [2] [.] [3] [4] and then Rotate the [ENTER] key. Entries may 90 deg. be made in exponential form using the [EXP] key. The entry above may be made by pressing [1] [.] [2] [3] [4] [EXP] [1] and then the [ENTER] key. [DISPLAY/SCALE] Select full screen or split screen display, settings or input/output monitor, and display scaling.
Keypad [PAUSE/RESET] will erase the data buffer whenever data acquisition is Paused or Done. To clear a buffer while a scan is in progress, two presses of the [PAUSE/RESET] key are required. However, at the end of a single shot scan, the data acquisition will be Done. This state is equivalent to a paused state and a single press of the [PAUSE/RESET] key will destroy the data! lighted trace identification at the upper left of each Trace 2 Y 36.000 S 58.332 e-3 display as illustrated below.
[AUTO PHASE] saved as well. When a trace is recalled from disk, the marks are recalled as well. Existing marks are replaced with the recalled marks. [AUTO PHASE] adjusts the reference phase shift so that the measured signal phase is 0°. This is done by subtracting the measured value of θ from the programmed reference phase shift. It will take several time constants for the outputs to reach their new values during which time θ will move towards 0°.
Keypad where XXXX is a file number. PCX files can be imported directly into many PC draw and paint programs and easily incorporated into word processing documents. Pressing [AUTO SCALE] when a chart graph is the active display will automatically set the vertical range and center value to display the entire range of the data. [AUTOSCALE] does not affect the horizontal scaling. [AUTOSCALE] only operates on the data which is presently displayed on the graph.
Keypad 4-24
REAR PANEL WARNING!: NO USER SERVICEABLE PARTS INSIDE. REFER TO USER MANUAL FOR SAFETY NOTICE. FOR USE BY QUALIFIED PERSONNEL ONLY. AUX IN AUX OUT X Y STANFORD RESEARCH SYSTEMS - MADE IN U.S.A.
NSIDE. AFETY NOTICE. NEL ONLY. REAR PANEL BNC CONNECTORS AUX IN AUX OUT X time is the scan length. Output voltage sweeps are coordinated with the data acquisition. Sweeps start and stop with the [START/CONT] and [PAUSE/RESET] keys. Pausing data acquisition will pause an Aux Out sweep. Resetting the data buffer will reset a sweeping Aux Out to its starting value. Y DE IN U.S.A. 1 1 X and Y 2 The X and Y lock-in outputs are always available at these connectors.
Rear Panel TRIG IN PREAMP CONNECTOR This TTL input may be used to trigger data samples and/or to start data acquisition. When the sample rate is set to Trigger, samples are recorded whenever there is a rising edge at the Trigger input. The maximum sample rate is 512 Hz. If the Trigger Starts is selected (in the AUX menu), then a rising edge will have the same effect as pressing the [START/CONT] key. Frequency and Aux Output sweeps will also start with this trigger.
Rear Panel 4-28
SR850 MENUS Default Settings Reference and Phase 5-2 Edit Mark 5-3 Internal/External Reference Internal Osc Frequency and Amplitude Internal Sweeps External Reference Modes Harmonic Detect Input and Filters Math 5-7 Disk 5-41 Save and Recall Data Save and Recall Settings Disk Utilities 5-9 System Setup Settings Sensitivity Dynamic Reserve Time Constant Filter Slope Synchronous Filtering Output and Offset 5-33 Smooth Fit Line, Exponential or Gaussian Calculator Stats Input Configuration Coupli
SR850 Menus DEFAULT SETTINGS If the [←] (backspace) key is held down when the power is turned on, the lock-in settings will be set to the defaults shown below rather than the settings that were in effect when the power was last turned off. The default settings may also be recalled using the ❊RST command over the computer interface. In this case, the communications parameters and status registers are not changed.
REFERENCE AND PHASE MENU Reference and Phase Ref. Phase 12.345 deg. The Reference and Phase menu sets the reference source, phase shift, and detection harmonic. The internal oscillator frequency , sweeps, and amplitude are also specified in this menu. REFERENCE PHASE Phase Shift Rotate 90 deg. Ref. Source 90° Shift Internal Ref Frequency Reference Source Internal Internal Sweep External 50.
Reference and Phase Menu Reference Source Ref. Source External Ref Slope Sine The Reference Source key selects the source of the lock-in reference. Turn the knob to select the desired source, either Internal , Internal Sweep, or External. Keypad entry is not allowed for this entry field. External When the reference source is External, the SR850 will phase lock to the external reference provided at the Reference Input BNC. The SR850 will lock to frequencies between 0.001 Hz and 102.0 kHz.
Reference and Phase Menu Ref. Source Internal Sweep Sweep Menu: Internal Sweep When the reference source is Internal Sweep, the SR850's synthesized internal reference is used as the reference and swept in frequency. Internal frequency sweeps are linked to the data acquisition scan. The frequency is changed once per sample (after the trace data is recorded) and sweeps from the start to stop frequency in one scan length amount of time. Pausing a scan with the [PAUSE RESET] key will pause a sweep.
Reference and Phase Menu Harmonic The SR850 can detect signals at harmonics of the reference frequency. The SR850 multiplies the input signal with digital sine waves at a multiple of the reference. Only signals at this harmonic will be detected. Signals at the original reference frequency are not detected and are attenuated as if they were noise. Pressing this key selects the harmonic number field as the active entry field.
INPUT AND FILTERS MENU Input and Filters The Input and Filters menu sets the input signal source and configuration. The input notch filters are also selected in this menu. See the SR850 Basics section for a discussion of the different input configurations and the signal filters.
Input and Filters Menu The current gain determines the input current noise as well as the input bandwidth. The 100 MΩ gain has 10 times lower noise but 100 times lower bandwidth. Make sure that the signal frequency is below the input bandwidth. The noise and bandwidth are listed below. Gain 1M 100M Noise 130 fA/√Hz 13 fA/√Hz Bandwidth 70 kHz 700 Hz The impedance of the signal source should be greater than 1 MΩ when using the 1M gain or 100 MΩ when using the 100M gain.
GAIN AND TIME CONSTANT MENU Gain and Time Cons The Gain and Time Constant menu sets the full scale sensitivity and dynamic reserve. The low pass filter time constant and slope are also selected in this menu. See the SR850 Basics section for a discussion of gain, time constants and dynamic reserve. Sensitivity 10 mV f.s. 60 dB gain GAIN TIME CONSTANT Reserve Max Min Manual Sensitivity Reserve Manual Reserve Max Min Manual 41 dB Time Constant 100 mS 1.2 Hz Manual Reserve Time Constant Filter dB/oct.
Gain and Time Constant Menu Reserve This key selects either maximum, minimum or manual dynamic reserve. When the reserve is maximum, the SR850 automatically selects the maximum reserve available at the present full scale sensitivity. When the reserve is minimum, the minimum available reserve is selected. The dynamic reserve is displayed in the settings display at the top of the screen (if selected in the DISPLAY/SCALE menu).
Gain and Time Constant Menu signal will obscure the signal at the reference and make detection difficult if not impossible. See the SR850 Basics section for more information. Man Reserve This key selects the Manual Reserve entry field for knob adjustment. Keypad entry is not allowed for this parameter. This menu box is available only if manual reserve is selected above. The reserve may be set between the minimum and maximum values in 10 dB increments.
Gain and Time Constant Menu <165 <175 10 s 30 s 12 dB/oct DC gain (dB) <55 <75 <95 <115 <135 <155 <175 min time constant 10 µs 30 µs 100 µs 300 µs 1 ms 3 ms 10 ms 18 dB/oct DC gain (dB) <62 <92 <122 <152 <182 min time constant 10 µs 30 µs 100 µs 300 µs 1 ms 24 dB/oct DC gain (dB) <72 <112 <152 <182 min time constant 10 µs 30 µs 100 µs 300 µs To use these tables, choose the correct table for the filter slope in use. Calculate the DC gain by adding the reserve to the expand (expressed in dB).
Gain and Time Constant Menu Filter dB/oct This key selects the low pass filter slope (number of poles). Each pole contributes 6 dB/oct of roll off. Using a higher slope can decrease the required time constant and make a measurement faster. The filter slope affects the minimum time constant (see above). Changing the slope may change the time constant if the present time constant is shorter than the minimum time constant at the new filter slope.
Gain and Time Constant Menu Use of the synchronous filter results in a reduction in amplitude resolution.
OUTPUT AND OFFSET MENU Output and Offset Front Panel CH1 The Output and Offset menu selects the CH1 and CH2 outputs and sets the X, Y and R offsets and expands. See the SR850 Basics section for a discussion of the DC outputs and scaling. OUTPUT OFFSET CH2 Source: CH1 or CH2 Output X Source Offset & Expand X Y R X, Y or R Output Offset: Offset 0.
Output and Offset Menu Output Offset and Expand The X, Y and R outputs may be offset and expanded. See the SR850 Basics section for a complete discussion of scaling, offsets and expands. Briefly, X, Y and R analog outputs (either the rear panel X and Y or the front panel CH1 or CH2 proportional to X, Y or R) are determined by Output = (signal/sensitivity - offset) x Expand x 10 V The output is normally 10 V for a full scale signal. The offset subtracts a percentage of full scale from the output.
TRACE AND SCAN MENU Trace and Scan Trace 1 2 3 ❊ X The Trace and Scan menu defines the four data traces and the data buffer usage. The sample rate and scan time for data storage and sweeps are set in this menu. See the Data Traces and Trace Scans and Sweeps discussion in the Screen Display Operation section for more information. TRACE SCAN 4 Trace 1, 2, 3 or 4 1 1 Define A•B/C Do Not Store Store Store/Do Not Store Sample Rate Sample Rate 1 Hz Scan Length Scan Length 16000.0 4:26:40.
Trace and Scan Menu The A, B and C parameters may be set to the quantities X, Y, R, θ, Xnoise, Ynoise, Rnoise, Aux Inputs 1-4 (on the rear panel), Frequency, and unity. C may also be any quantity squared. X, Y, R and θ are the normal lock-in output quantities. Frequency is useful when the reference is unknown or changing (as in an external sweep). The rear panel aux inputs can digitize a slowly varying signal with16 bits of resolution to monitor external parameters which affect the lock-in measurement.
Trace and Scan Menu Aliasing effects can occur whenever the trace being sampled contains signals at frequencies greater than twice the sample rate. The effect is most noticeable when trying to sample an output whose frequency is a multiple of the sample rate. Generally, the highest possible sample rate should be used given the desired scan length and the buffer size. The time constant and filter slope should be chosen to eliminate output signals at frequencies higher than twice the sample rate.
Trace and Scan Menu 5-20
DISPLAY AND SCALE MENU Display and Scale Format Single Up/Down The Display and Scale menu selects the screen format, the displayed traces, and the display types. The bar graph and chart display scales may be adjusted in this menu. See the Operation section for more information about the different displays. DISPLAY SCALE Monitor Settings Input/Output Format Monitor Display Scale Full Top Bottom Type: Full, Top or Bottom Display Chart Trace: 1 Type ± 1.000 e0 Range @ 0.
Display and Scale Menu Full, Top or Bottom Display Pressing this key selects which display's type, trace and scaling will be adjusted and displayed in this menu box. If the format is full screen, the top and bottom displays can not be selected. If the format is dual display, then only top or bottom can be selected. Type and Trace Pressing this key highlights the boxed parameter (either Type or Trace). The highlighted parameter may be changed using the knob.
Display and Scale Menu Seconds/div Chart graphs have a horizontal scale which determines how much of the data buffer will be displayed. The horizontal scale is the number of seconds per division across the graph. By changing the horizontal scale, the entire trace buffer can be displayed at once or a small portion may be expanded. If only a portion of the buffer is displayed, use the cursor to pan right and left within the buffer.
Display and Scale Menu 5-24
AUX OUTPUTS MENU Aux Outputs Aux. Output 1 2 Fixed 3 4 Log The Aux Outputs menu programs the rear panel auxiliary D/A outputs. The outputs may be set to fixed voltages or programmed to sweep. In addition, the Trigger input can be configured to start scans. AUX OUTPUTS Aux Output 1, 2, 3 or 4 Linear Fixed Voltage Log or Linear 2.
Aux Outputs Menu Voltage This menu box displays the fixed voltage at the selected aux output. This menu box is only displayed if the output is Fixed. If the output is Fixed, pressing this key will select the voltage as the active entry field. The fixed voltage level can be adjusted with the knob or entered from the keypad. The voltage can range from -10 V to +10 V with 1 mV resolution. Sweep Limits An output which is in linear or log sweep mode has its sweep limits and offset value displayed.
Aux Outputs Menu A log sweep from a higher voltage to a lower voltage is just the reverse progression as the sweep from lower to higher. More time will be spent at lower voltages. Sweep Limits Start: 1.000 V Stop: 2.000 V Start If the selected aux output is in a sweep mode, then pressing this key will select the start voltage as the active entry field. The value may be adjusted with the knob or entered with the keypad. The start voltage can range from 0.001 V to 21 V.
Aux Outputs Menu 5-28
CURSOR SETUP MENU Cursor Setup Cursor Seek Max Min Mean The Cursor Setup menu is activated with the [CURSOR SETUP] key in the Entry area of the keypad. This menu is used to set the cursor modes. Each display (full, top or bottom) has its own cursor (which is active only if the display is a chart). The cursor information displayed in this menu is for the active display.
Cursor Setup Menu Cursor Width This function selects the width of the cursor region defined by the vertical dashed lines on the chart display. Cursors are available only for chart displays. Each display (full, top or bottom) has its own cursor width. Narrow is 1/2 of a division, Wide is 1 division, and Spot is a single horizontal position on the graph (the cursor is a single dashed line). Off removes the cursor from the graph.
EDIT MARK MENU Edit Mark The Edit Mark menu is activated with the [EDIT MARK] key in the Entry area of the keypad. This menu is used to label marks in the data buffer. See the discussion on chart graphs in the Operation section for more information about marks. The cursors may also be moved to the mark locations. Marks may only be inserted, edited or deleted if the active display is a chart display. Marks are saved with the trace data when data is saved to disk.
Edit Mark Menu Edit Mark Entry Mode Overstrike Insert Character Space: Delete: This key activates a submenu which allows marks to be labelled and viewed. This key will select the nearest mark to the left of the cursor (towards older points) and display the trace values and mark time and label on the screen. The mark label may be entered or edited with the submenu. The square entry cursor indicates where text will be entered in the label. Use the knob to move the square back and forth.
MATH MENU Math The Math menu is used to smooth, fit, change and analyze trace data. Math functions only operate on the data which is displayed within the active display. Math MATH Smooth: Smooth Fit: Fit Calc: Calc Stats: Math Keys Stats Each Math key activates a sub menu. Each sub menu is described in detail in the following pages. Math functions may only be performed on trace data which is stored in a trace buffer and displayed in the active chart display.
Math Menu Smooth The Smooth sub menu will smooth the data within the active chart display using the Savitsky-Golay algorithm. For details on the SavitskyGolay smoothing technique, see Abraham Savitsky and Marcel J. E. Golay, "Smoothing and Differentiation of Data by Simplified Least Squares Procedures", Analytical Chemistry, (36) 8, July 1964. In essence, smoothing removes features which are narrower than the number of smoothing points.
Math Menu Fit The Fit sub menu allows the user to fit one of three curves to the data within the active chart display - lines, exponentials, and Gaussians. Fitting is done using the Marquardt 'Gradient-expansion' algorithm to minimize chi-squared. MATH Do Fit: Type of Fit Line Exp Gauss Fit Do Fit View Params: Fit Type Limits View Parameters Left: Left Limit Right: Right Limit Return: Return Do Fit Abort Pressing this key starts the actual fit calculations.
Math Menu re-entered, the View Parameters function will re-display the best fit curve and the parameter window. Both the Do Fit and View Parameters functions result in a display screen like the one shown below. Full Scale = 100 mV Dyn Reserve = 23 dB Trace 2 Y 100 mS Syncro 12 dB/oct Line 2xLin AC A 7.000 S 36.100 e-3 Do Fit: Type of Fit Line Exp Gauss y = a + b•(t-t0) t0 = 9.600000e+001 s a = -2.875882e-003 b = 1.136381e-003 View Params: Limits Left: Right: center = 0.0 10 S /div ± 50.00 e-3 0.
Math Menu Full Scale = 100 mV Dyn Reserve = 23 dB Trace 2 Y 100 mS Syncro 12 dB/oct Line 2xLin AC A 7.000 S 36.100 e-3 Do Fit: Type of Fit Line Exp Gauss View Limit Markers Params: Limits Left: Right: center = 0.0 Done Return 10 S /div ± 50.00 e-3 Intrnl Fr= 100.00 Hz LOCK Harmonic= 1 0.000 S V Return: LOC The Return key will return to the main Math menu. Re-entering the Fit menu and using the View Parameters function will re-display the most recent fit.
Math Menu Calc The Calculation sub menu allows the user perform simple arithmetic calculations with data displayed in the active chart. Operations are performed only on the data within the chart, not the entire trace buffer. An operation which overflows (such as divide by zero) will display an error message and abort. Performing a calculation on the data will change the data. Once changed, the data can not be restored to its original values.
Math Menu Argument Type The +, -, x, / operations require a second argument. The Argument Type function selects between a constant argument and another trace. A constant argument adds or subtracts a constant to the trace or multiplies or divides the trace by a constant. A trace argument uses a data trace as the argument. In this case, calculations are performed on a point by point basis. The trace which is in the active chart display is where the results are stored.
Math Menu Stats The Stats sub menu calculates a variety of statistical information about a chart display calculation region defined by the Left and Right Limits. MATH Do Stats: Stats Do Stats Limits Left: Left Limit Right: Right Limit Return: Return Do Stats Pressing this key starts the actual calculation. While calculations are in progress, the "Calculating Statistics..." message is displayed at the bottom of the screen.
DISK MENU Disk The Disk menu is used to save and recall data and settings to and from disk. The Disk Utilities submenu can erase files and format blank disks. Files are saved as DOS files and can be read by a DOS compatible computer with a 3.5" disk drive. The SR850 uses double sided, double density disks (DS/DD). Do not use high density (DS/HD) disks. The maximum number of files allowed on a disk is 114. This is the DOS limitation on the number of directory entries in the root directory.
Disk Menu Save Data The Save Data submenu is used to save the trace data which is on the active chart display to the disk. Save Data Data Save: ASCII Save: Pressing this key will save the trace which is displayed by the active chart display to the file specified in the File Name field. Only a single trace is saved in a file, even if more traces are stored in the buffer. If the active display is not a chart, no action is taken.
Disk Menu Full Scale = 10 mV Dyn Reserve = 3 dB 100 mS Syncro 12 dB/oct Line 2xLin AC A Name Ext Type Size Date ABCD DAT TRC 1894 02/07/91 22:53:10 450 16384 16384 02/22/91 03/13/91 04/11/91 14:47:28 09:21:41 11:21:01 TEST 85S SET SPECT1 85T TRC MYDATA 85T TRC Data Save: Time ASCII Save: File Name ABCD.DAT Catalog On Stop Free = 720280 bytes Intrnl Fr= 100.
Disk Menu Recall Data The Recall Data submenu is used to recall data from a binary disk file into the trace which is displayed by the active display. For example, if the full screen display is a chart showing Trace 2, then recalling a trace from disk will read the file into Trace 2. The stored trace definition is recalled with the data and changes the definition of Trace 2. All stored traces must have the same length.
Disk Menu Data Recall Data Recall: Pressing this key will recall the trace data and instrument state from the file specified in the File Name field. If the file specified is not on the disk or is not a data file, then an error message will appear. Ascii files may not be recalled. File Name This key activates the File Name entry field. File names are entered using the keypad and alternate keypad. The [ALT] key allows letters to be entered. DOS file name conventions must be followed, i.e.
Disk Menu Save Settings Setting The Save Settings submenu is used to save the lock-in settings to a disk file. The settings include all parameters which are set with the menus. Save Settings Pressing this key will save the current lock-in settings to the file specified in the File Name field. File Name This key activates the File Name entry field. File names are entered using the keypad and alternate keypad. The [ALT] key allows letters to be entered. DOS file name conventions must be followed, i.e.
Disk Menu Recall Settings Setting The Recall Settings submenu is used to recall the lock-in settings from a disk file. The settings include all parameters which are set with the menus. Recall Settings Pressing this key will read the settings information from the file specified in the File Name field. The lock-in will be configured according to the recalled settings. Any trace data presently in memory is lost. File Name This key activates the File Name entry field.
Disk Menu Disk Utilities File The Disk Utilities submenu contains the Format Disk and Erase File functions. These functions should be used with care since disk data will be erased. The catalog screen may be displayed with this submenu if a formatted disk is in the drive. Erase File This function will erase the file specified in the File Name field. Make sure the selected file is the correct file before pressing this key. Format Disk Pressing this key will format the disk.
SYSTEM SETUP MENU System Setup Settings: The System Setup menu is used to configure the system parameters. The Settings submenu configures the printer, plotter and computer interfaces, and the screen, sound and clock/calendar parameters. The Plot submenu is used to plot the screen display to an HPGL compatible plotter. The Info submenu displays various information screens. The Test submenu selects various hardware tests.
System Setup Menu Settings Settings Com: The Settings menu is used to configure the printer, plotter and computer interfaces, and to set the screen, sound and clock/calendar parameters. Settings Screen: SYSTEM SETUP Settings Sound: Time: Plotter: Communications Screen Sound Time Plotter Printer: Printer More: More Return: Return: Return Settings Keys Return The Settings menu consists of two menus, with each key activating a submenu.
System Setup Menu Setup Communications Output To RS-232 GPIB Setup Communication parameters in this submenu should not be altered while the computer interface is active. SYSTEM SETUP Settings RS232: Communications Setup GPIB: Output To RS232/GPIB View Queues: Setup RS232 Return: Setup GPIB Baud Rate GPIB Address Word Length Overide Remote ? Parity Return Return View Queues Return Output to RS232/GPIB The SR850 only outputs data to one interface at a time.
System Setup Menu Setup RS232 Baud Rate The Setup RS232 key activates the RS232 parameters submenu. Baud rate, word length, and parity may be configured in this submenu. Baud Rate The Baud Rate key allows the knob to adjust the RS232 baud rate. The baud rate can be set to any standard value from 300 to 19200 baud. Word Length This key toggles the character length. The RS232 character length can be 7 or 8 bits. 8 bits is standard. Parity This key toggles the parity.
System Setup Menu View Queues The last 256 characters received or transmitted by the SR850 may be displayed to help find programming errors. The View Queues key will display the interface buffers at the time the key is pressed. This screen is updated regularly to display new interface activity. The View Queues screen may slow down the communications between the SR850 and a host computer. In general, the View Queues screen should be displayed only when testing or debugging a host program.
System Setup Menu Setup Sound Key Click On Off Alarms On The Setup Sound key activates the sound submenu. Key click and alarms are enabled and disabled in this menu. SYSTEM SETUP Settings Off Sound Key Click On/Off Alarms On/Off Return Return: Key Click This key turns the key click on and off. Alarms This key enables and disables the audible alarms. Alarms will sound whenever a front panel programming error or interface error occurs.
System Setup Menu Setup Plotter Plot Mode RS232 GPIB Baud Rate The Setup Plotter submenu configures the SR850 plotter driver. Interface, plot speed, and pen definitions are set in this submenu. To actually start plotting, use the [PLOT] key to select the Plot menu.
System Setup Menu Plotter Addr. Plotter Addr. 1 If the Plot Mode is GPIB, then the Plotter Address must be set. The Plotter Address may be entered from the keypad or by using the knob. The Plotter Address must agree with the address of the plotter in use. In this mode, the plotter must be the only device attached to the SR850 GPIB interface. Plot Speed This key toggles the Plot Speed. Normally, when plotting on paper, the Fast Plot Speed is used.
System Setup Menu Setup Printer Printer Type Epson HP File The Setup Printer menu is used to select the type of printer attached to the parallel printer port. The [PRINT] key prints the screen to the printer. If File is chosen as the printer type, then [PRINT] will save the screen image as a PCX file on the disk. SYSTEM SETUP Settings Printer Printer Type Return Return: Printer Type This function toggles the Printer Type between Epson, HP and File.
System Setup Menu Setup Screen The Setup Screen submenu is used to adjust the position of the display on the screen. The display area may be moved left, right, up and down. Move SYSTEM SETUP Right: Settings Left: Screen Up: Move Right Move Left Down: Move Up Move Down Return: Return The screen position is stored in non-volatile memory and is retained when the power is turned off. To restore the screen to the default position, power the unit on with the [←] (backspace) key pressed.
System Setup Menu Setup Time The Setup Time key activates the clock/calendar submenu. The time and date are used to label all screen prints and plots as well as disk files. This menu is used to check or change the time and date. Time SYSTEM SETUP 03 : 45 : 12 Date Settings 03 / 15 / 91 Time Time Date Return Return: Time The time is displayed as hours:minutes:seconds. A 24 hour format is used. This key toggles the entry field from hours to minutes to seconds. A new entry may be made using the knob.
System Setup Menu 5-60
System Setup Menu Plot Plot All: The Plot submenu is used to plot the screen display to an HPGL compatible plotter. Use the Plotter Settings menu to configure the plotter interface. SYSTEM SETUP Plot Trace: Plot All Cursor: Plot Trace Plot Cursor Abort Plot: Abort Plot Return: Return Plot All The Plot All key generates a plot of the entire display, including the scale and marker information. In single display format only the full screen graph is plotted.
System Setup Menu 5-62
System Setup Menu Info About the SR850: The Info submenu displays various information screens which may be helpful to the user. SYSTEM SETUP Info About SRS: About the SR850 Operating Hints: About SRS Command List: Operating Hints Status Bytes: Command List Status Bytes Return: Return About the SR850 This key displays the SR850 specifications. About SRS This key displays information about Stanford Research Systems, Inc.
System Setup Menu 5-64
System Setup Menu Test Hardware The Test submenu allows the user to test various features of the SR850 such as the keypad, knob, screen, memory, etc. Use the More softkey to select the second test menu screen.
System Setup Menu Disk Drive Test Pressing this key activates the disk drive test screen. Continuing with this test will destroy any data on the disk currently in the drive. Therefore remove any disk containing data from the drive and insert a scratch disk. This test will check the controller, format the disk, and read and write data to the disk. The entire test takes approximately 2 minutes. Use the Return function to skip this test and return to the previous menu.
REMOTE PROGRAMMING INTRODUCTION The SR850 DSP Lock-in Amplifier may be remotely programmed via either the RS232 or GPIB (IEEE-488) interfaces. Any computer supporting one of these interfaces may be used to program the SR850. Both interfaces are receiving at all times, however, the SR850 will send responses only to the interface specified in the System Setup menu (Output To RS232/GPIB function). Use the OUTX command at the beginning of every program to direct the responses to the correct interface.
Remote Programming computer is ready to receive. If either buffer overflows, both buffers are cleared and an error reported. sent, the Status Bytes should be queried. When using the GPIB interface, serial polling may be used to check the Interface Ready bit in the Serial Poll Byte while an operation is in progress. After the Interface Ready bit becomes set, signalling the completion of the command, then the ERR or ESB bit may be checked to verify successful completion of the command.
Remote Programming DETAILED COMMAND LIST The four letter mnemonic in each command sequence specifies the command. The rest of the sequence consists of parameters. Multiple parameters are separated by commas. Parameters shown in { } are optional or may be queried while those not in { } are required. Commands that may be queried have a question mark in parentheses (?) after the mnemonic. Commands that may ONLY be queried have a ? after the mnemonic. Commands that MAY NOT be queried have no ?.
Remote Programming REFERENCE and PHASE COMMANDS PHAS (?) {x} The PHAS command sets or queries the reference phase shift. The parameter x is the phase (real number of degrees). The PHAS x command will set the phase shift to x. The value of x will be rounded to 0.001°. The phase may be programmed from -360.000 ≤ x ≤ 719.999 and will be wrapped around at ±180°. For example, the PHAS 541.0 command will set the phase to -179.000° (541-360=181=-179). The PHAS? queries the phase shift.
Remote Programming HARM (?) {i} The HARM command sets or queries the detection harmonic. This parameter is an integer from 1 to 32767. The HARM i command will set the lock-in to detect at the ith harmonic of the reference frequency. The value of i is limited by ixf ≤ 102 kHz. If the value of i requires a detection frequency greater than 102 kHz, then the harmonic number will be set to the largest value of i such that ixf ≤ 102 kHz.
Remote Programming INPUT and FILTER COMMANDS ISRC (?) {i} The ISRC command sets or queries the input configuration. The parameter i selects A (i=0), A-B (i=1) or I (i=2). IGAN (?) {i} The IGAN command sets or queries the conversion gain of the current input. The parameter i selects 1 MΩ (i=0), 100 MΩ (i=1). This parameter has no effect unless the input is configured to measure current. Changing the current gain does not change the instrument sensitivity.
Remote Programming GAIN and TIME CONSTANT COMMANDS SENS (?) {i} The SENS command sets or queries the sensitivity. The parameter i selects a sensitivity below.
Remote Programming Time constants greater than 30s may NOT be set if the harmonic x ref. frequency (detection frequency) exceeds 200 Hz. Time constants shorter than the minimum time constant (based upon the filter slope and dynamic reserve) will set the time constant to the minimum allowed time constant. See the GAIN/TC menu section. OFSL (?) {i} The OFSL command sets or queries the low pass filter slope. The parameter i selects 6 dB/oct (i=0), 12 dB/oct (i=1), 18 dB/oct (i=2) or 24 dB/oct (i=3).
Remote Programming OUTPUT and OFFSET COMMANDS FOUT (?) i {, j} The FOUT command sets or queries the front panel (CH1 and CH2) output sources. The parameter i selects CH1 (i=1) or CH2 (i=2) and is required. The FOUT i, j command sets output i to quantity j where j is listed below. The definition of j is different for the two outputs.
Remote Programming TRACE and SCAN COMMANDS TRCD (?) i {, j, k, l, m} The TRCD command sets or queries the trace definitions. The parameter i selects the trace number (1, 2, 3 or 4) and is required. The TRCD i, j, k, l, m command defines trace i to quantity j times quantity k divided by quantity l and the trace will be stored (m=1) or not stored (m=0). This command requires all of the parameters. The parameters j, k and l select the quantities listed below. Only l can be greater than 12.
Remote Programming DISPLAY and SCALE COMMANDS ASCL The ASCL command auto scales the active display. This command is just like pressing the [AUTO SCALE] key. Only Bar and Chart displays are affected. ADSP (?) {i} The ADSP command selects the active display. The parameter i selects Full (i=0), Top (i=1) or Bottom (i=2). The selected display must be presently displayed on the screen otherwise an error will result. SMOD (?) {i} The SMOD command sets or queries the screen format.
Remote Programming DHZS (?) i {, j} The DHZS command sets or queries the display horizontal scale. The parameter i selects the Full (i=0), Top (i=1) or Bottom (i=2) display and is required. The parameter j selects a scale listed below. An error is generated if the DHZS command tries to set the horizontal scale of a display which is not on the screen. The horizontal scale only affects chart display types. i 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 time/div 2 mS 5 mS 10 mS 20 mS 50 mS 0.1 S 0.2 S 0.5 S 1.
Remote Programming CURSOR COMMANDS CSEK (?) {i} The CSEK command sets or queries the cursor seek mode of the active display. The parameter i selects Max (i=0), Min (i=1) or Mean (i=2). Each display has its own cursor seek mode. Use the ATRC and SMOD commands to select the desired display. Only chart displays have a cursor. CWID (?) {i} The CWID command sets or queries the cursor width of the active display. The parameter i selects Off (i=0), Narrow (i=1), Wide (i=2) or Spot (i=3).
Remote Programming MARK COMMANDS MARK The MARK command is just like pressing the [MARK] key. A mark will be placed in the data buffer at the next sample. This command has an effect only when a scan is in progress. CNXT The CNXT command moves the cursor of the active chart display to the next mark to the right. If the mark is off the right edge of the graph, then the display is panned to the right until the next mark is found.
Remote Programming AUX INPUT and OUTPUT COMMANDS OAUX? i The OAUX? command queries the Aux Input values. The parameter i selects an Aux Input (1, 2, 3 or 4) and is required. The Aux Input voltages are returned as ASCII strings with units of Volts. The resolution is 1/3 mV. This command is a query only command. AUXM (?) i {, j} The AUXM command sets or queries the Aux Output mode. The parameter i selects an Aux Output (1, 2, 3 or 4) and is required.
Remote Programming MATH COMMANDS The math functions operate on the trace which is graphed in the active display. If the display type is polar, then the trace most recently displayed (in a bar or chart) will be used. If the active display trace is not stored, then the math functions will generate an error and have no effect. The Smooth and Calculator functions CHANGE the stored data. Only the data which is within the time window of the chart graph is operated upon.
Remote Programming CALC The CALC command starts the calculation selected by the COPR command. This may take some time. Use a status query command to detect when the calculation is done. Make sure that CTRC or CARG have been used to set the argument (if required by the operation) before using the CALC command. If a scan is in progress, the CALC command will Pause the scan. CAGT (?) {i} The CAGT command sets or queries the argument type. The parameter i selects Trace (i=0) or Constant (i=1).
Remote Programming STORE AND RECALL FILE COMMANDS When using file commands, the status byte should be queried after the command is sent to check if the command generated an error. Common sources of errors are file not on disk, no space on disk, and no disk in drive. For example, the command line SDAT;ERRS? will save the data to disk and return the Error Status Byte when finished. The Disk Error bit may be checked to make sure that the Save Trace command terminated without error.
Remote Programming SETUP COMMANDS OUTX (?) {i} The OUTX command sets the output interface to RS232 (i=0) or GPIB (i=1). The OUTX i command should be sent before any query commands to direct the responses to the interface in use. OVRM (?) {i} The OVRM command sets or queries the GPIB Overide Remote Yes/No condition. The parameter i selects No (i=0) or Yes (i=1). KCLK (?) {i} The KCLK command sets or queries the key click On (i=1) or Off (i=0) state.
Remote Programming PNGD (?) {i} The PNGD command sets or queries the grid pen number. The pen number is in the range of 1 to 6. PNAL (?) {i} The PNAL command sets or queries the alphanumeric pen number. The pen number is in the range of 1 to 6. PNCR (?) {i} The PNCR command sets or queries the cursor pen number. The pen number is in the range of 1 to 6. PRNT (?) {i} The PRNT command sets or queries the printer type. The printer type may be EPSON (i=0), HP (i=1) or File (i=2).
Remote Programming PRINT and PLOT COMMANDS PRSC The PRSC command will print the screen display to a printer attached to the rear panel parallel printer port. This function is the same as the [PRINT] key. The printer type needs to be selected before using the PRSC command. PALL The PALL command generates a plot of the data displays. Each feature uses the pen assigned in the Setup Plotter menu. PTRC The PTRC command plots only the data trace(s).
Remote Programming FRONT PANEL CONTROLS and AUTO FUNCTIONS STRT The STRT command starts or resumes a scan (and sweep). This function is the same as pressing the [START/CONT] key. STRT is ignored if a scan is already in progress. PAUS The PAUS command pauses a scan. All sweeps in progress also pause. If a scan is already paused, stopped or done, then this command is ignored (the scan is not reset). REST The REST command resets a scan.
Remote Programming DATA TRANSFER COMMANDS OUTP ? i The OUTP? i command reads the value of X, Y, R or . The parameter i selects X (i=1), Y (i=2), R (i=3) or θ (i=4). Values are returned as ASCII floating point numbers with units of Volts or degrees. For example, the response might be "-1.01026". This command is a query only command. OUTR ? i The OUTR? i command reads the value of trace 1, 2, 3 or 4. The parameter i selects the trace (i=1, 2, 3 or 4).
Remote Programming and θ are also recorded at a single instant. Thus reading X,Y OR R,θ yields a coherent snapshot of the output signal. If X,Y,R and θ are all read, then the values of X,Y are recorded approximately 10µs apart from R,θ. Thus, the values of X and Y may not yield the exact values of R and θ from a single SNAP? query. The values of the Aux Inputs may have an uncertainty of up to 32µs. The frequency is computed only every other period or 40 ms, whichever is longer.
Remote Programming transfer does not pause between bytes. The receiving interface must always be ready to receive the next byte. In general, using binary transfers on the RS232 interface is not recommended. The parameter i selects a trace (1, 2, 3 or 4) and is required. If Trace i is not stored, then an error occurs. Points are read from the buffer starting at bin j (j≥0). A total of k bins are read (k≥1) for a total transfer of k*4 bytes. To read a single point, set k=1. Both j and k are required.
Remote Programming The parameter i selects a trace (1, 2, 3 or 4) and is required. If Trace i is not stored, then an error occurs. Points are read from the buffer starting at bin j (j≥0). A total of k bins are read (k≥1) for a total transfer of k*4 bytes. To read a single point, set k=1. Both j and k are required. If j+k exceeds the number of stored points (as returned by the SPTS? query), then an error occurs.
Remote Programming talker and the controlling interface a listener. Remember, the first transfer will occur with the very first point in the scan. If the scan is started from the front panel or from the trigger input, then make sure that the SR850 is a talker and the controlling interface a listener BEFORE the scan actually starts. STRD After using FAST1 or FAST 2 to turn on fast data transfer, use the STRD command to start the scan. STRD starts a scan after a delay of 0.5 sec.
Remote Programming INTERFACE COMMANDS ❊RST The ❊RST command resets the SR850 to its default configurations. The communications setup is not changed. All other modes and settings are set to their default conditions and values. This command takes some time to complete. ❊IDN? The ❊IDN? query returns the SR850's device identification string. This string is in the format "Stanford_Research_Systems,SR850,s/ n00111,ver1.000". In this example, the serial number is 00111 and the firmware version is 1.000.
Remote Programming STATUS REPORTING COMMANDS The Status Byte definitions follow this section. ❊CLS The ❊CLS command clears all status registers. The status enable registers are NOT cleared. ❊ESE (?) {i} {,j} The ❊ESE i command sets the standard event enable register to the decimal value i (0-255). The ❊ESE i,j command sets bit i (0-7) to j (0 or 1). The ❊ESE? command queries the value (0-255) of the status byte enable register. The ❊ESE? i command queries the value (0 or 1) of bit i.
Remote Programming STATUS BYTE DEFINITIONS The SR850 reports on its status by means of four status bytes: the Serial Poll Status byte, the Standard Event Status byte, the LIA Status byte, and the Error Status byte. The status bits are set to 1 when the event or state described in the tables below has occurred or is present. SERIAL POLL STATUS BYTE bit name usage 0 SCN No scan in progress (Stop or Done). A Paused scan is considered to be in progress. 1 IFC No command execution in progress.
Remote Programming SERVICE REQUESTS (SRQ) A GPIB service request (SRQ) will be generated whenever a bit in both the Serial Poll Status byte AND Serial Poll Enable register is set. Use ✳SRE to set bits in the Serial Poll Enable register. A service request is only generated when an enabled Serial Poll Status bit becomes set (changes from 0 to 1). An enabled status bit which becomes set and remains set will generate a single SRQ.
Remote Programming LIA STATUS BYTE bit name usage 0 INPUT/RESRV Set when an INPUT or RESRV overload is detected. 1 FILTR Set when a FILTR overload is detected. 2 OUTPT Set when an OUTPT overload is detected. 3 UNLK Set when a reference unlock is detected. 4 RANGE Set when the detection frequency switches ranges (harmonic x ref. frequency decreases below 199.21 Hz or increases above 203.12 Hz). Time constants above 30 s and Synchronous filtering are turned off in the upper frequency range.
Remote Programming EXAMPLE PROGRAM 1 Using Microsoft C (v5.1) with the National Instruments GPIB card on the IBM PC. To successfully interface the SR850 to a PC via the GPIB interface, the instrument, interface card, and interface drivers must all be configured properly. To configure the SR850, the GPIB address must be set in the SYSTEM SETUP menu. The default GPIB address is 8; use this address unless a conflict occurs with other instruments in your system.
Remote Programming /* function prototypes */ void void void void void void void main(int, char *[]); txLia(char *); initGpib(char *); setupLiaForSweep(void); printOutBinaryResults(); printOutIEEEResults(); printOutLIAResults(); /* National Instruments Interface Function Prototypes (488.1 Calls - see the National software manual).
Remote Programming printOutBinaryResults(); /* format and print the results */ printf("\n%d bytes received.\nPress to continue.
Remote Programming printf("\n\n"); for (i=0;i<10;i++) printf("%d %e\n",i,rfBuf[i]); /* this is simple since the values are already floats */ } void printOutLIAResults(void) { /* calculates the first 10 values of R transferred in LIA float format by the SR850 */ int i,mant,exp; int *ptr; float val; printf("\n\n"); ptr =(int *) rfBuf; /* ptr points to integers in rfBuf, not floats! */ for (i=0;i<10;i++) { mant = *ptr++; /* first comes the mantissa (16 bits) */ exp = *ptr++ - 124; /* then the binary expone
Remote Programming txLia("DSCL0,.5;DOFF0,.5"); txLia("DHZS0,11"); /* set scale from 0 to 1 V */ /* set 10s/div horizontal */ printf("Scan is Initialized, Press to Begin Scan...
Remote Programming 6-38
Remote Programming EXAMPLE PROGRAM 2 Using Microsoft QUICKBASIC (v4.5) with the National Instruments GPIB card on the IBM PC. To successfully interface the SR850 to a PC via the GPIB interface, the instrument, interface card, and interface drivers must all be configured properly. To configure the SR850, the GPIB address must be set in the SYSTEM SETUP menu. The default GPIB address is 8; use this address unless a conflict occurs with other instruments in your system.
Remote Programming ' ' Look for device named "LIA". Use IBCONF to configure the device "LIA" as above. Assign the device handle to variable LIA%. BDNAME$ = "LIA" CALL IBFIND(BDNAME$, LIA%) ' Check for error on IBFIND call. IF LIA% < 0 THEN CALL FINDERR ' Reset the device. WRT$ = "*RST" CALL TXLIA(LIA%, WRT$) CALL IBCLR(LIA%) PRINT "The SR850 is reset. Now initialize the scan" PRINT "Press to continue.
Remote Programming WRT$ = "FAST2;STRD" CALL TXLIA(LIA%, WRT$) ' Get FAST mode data. ' The 100 sec sweep at 64 Hz has 64*100 + 1 points, each point consists of X (2 bytes) and Y (2 bytes) ' for a total of 4 bytes per sample. 6401*4=25604 bytes. CALL IBRDI(LIA%, RXBUF%(), 25604) PRINT "Scan Finished."; IBCNT%; "Bytes Received" ' Now print out the first 10 values of R based on the X and Y values FOR I% = 0 TO 9 ' the buffer contains X,Y pairs so move by 2*I% to find the next point.
Remote Programming EXPONENT% = RXBUF%(2 * I% + 1) - 124 ' compute the floating point value R = MANTISSA% * 2! ^ EXPONENT% PRINT "I ="; I%; " R ="; R NEXT I% END SUB FINDERR STATIC PRINT "IBFIND ERROR" END SUB SUB TXLIA (LIA%, SND$) CALL IBWRT(LIA%, SND$) ' wait until the command is finished executing DO CALL IBRSP(LIA%, SPR%) LOOP WHILE (SPR% AND 2) <> 2 END SUB 6-42
PERFORMANCE TESTS Introduction Knob The performance tests described in this section are designed to verify with a high degree of confidence that the unit is performing within the specifications. The knob is used to adjust parameters which have been highlighted using the softkeys. Most numeric entry fields may be adjusted using the knob. In addition, parameters such as sensitivity and time constant use the knob as well. In these cases, the knob function is selected by the softkeys.
Performance Tests General Installation POWER Make sure that the power entry module on the rear panel is set for the AC line voltage in your area and that the correct fuse is installed. The selected AC voltage may be seen through the window on the power entry module. Verify that the line cord is plugged all the way into the power entry module and that the power button on the front panel is pressed in.
Performance Tests Necessary Equipment Warm Up The following equipment is necessary to complete the performance tests. The suggested equipment or its equivalent should be used. The lock-in should be turned on and allowed to warm up for at least an hour before any tests are performed. The self test does not require any warm up period. 1. Frequency Synthesizer Freq Range 1 Hz to 1 MHz Freq Accuracy better than 5 ppm Amplitude Accuracy 0.
Performance Tests 7-4
Performance Tests 1. Self Tests The self tests check the lock-in hardware. These are functional tests and do not relate to the specifications. These tests should be run before any of the performance tests. Note that the Hardware Test menu offers more tests than are required here. Only those tests which require no additional equipment are discussed in this section. The computer interface and disk drive tests are not required but should be periodically checked.
Performance Tests 7-6
Performance Tests 2. DC Offset This test measures the DC offset of the input. Setup Connect a 50Ω terminator to the A input. This shorts the input so the lock-in's own DC offset will be measured. Procedure 1) {PRESET} (Turn the lock-in off and on with the [←] key pressed) 2) Press the keys in the following sequence: [REF/PHASE] [1] [ENTER] [GAIN/TC] Use the knob to select 1 mV. [DISPLAY/SCALE] Highlight the trace number.
Performance Tests 7-8
Performance Tests 3. Common Mode Rejection This test measures the common mode rejection of the lock-in. Setup We will use the internal oscillator sine output to provide the signal. Connect the Sine Out to both the A and B inputs of the lock-in. Use equal length cables from A and B to a BNC TEE. Connect the cable from the Sine Out to the TEE. Do not use any termination.
Performance Tests 7-10
Performance Tests 4. Amplitude Accuracy and Flatness This test measures the amplitude accuracy and frequency response. Setup We will use the frequency synthesizer to provide an accurate frequency and the AC calibrator to provide a sine wave with an exact amplitude. Connect the output of the frequency synthesizer to the phase lock input of the calibrator. Connect the output of the AC calibrator to the A input of the lock-in. Be sure to use the appropriate terminations where required.
Performance Tests a) Set the AC calibrator to the amplitude shown in the table. b) Press Use the knob to select the sensitivity from the table. c) Wait for the R reading to stabilize. Record the value of R for each sensitivity. 4) Frequency response is checked at frequencies above 1 kHz. The test frequencies are listed below. Test Frequencies 24 kHz 48 kHz 72 kHz 96 kHz a) Set the AC calibrator to 1 kHz and an amplitude of 200.00 mVrms. b) Set the frequency synthesizer to 1 kHz.
Performance Tests 5. Amplitude Linearity This test measures the amplitude linearity. This tests how accurately the lock-in measures a signal smaller than full scale. Setup We will use the frequency synthesizer to provide an accurate frequency and the AC calibrator to provide a sine wave with an exact amplitude. Connect the output of the frequency synthesizer to the phase lock input of the calibrator. Connect the output of the AC calibrator to the A input of the lock-in.
Performance Tests 3) For each of the amplitudes listed below, perform steps 3a through 3c. AC Calibrator Amplitudes 1.0000 Vrms 100.00 mVrms 10.000 mVrms 4.000 mVrms R Output Expand 1 10 100 250 a) Set the AC calibrator to the amplitude in the table. b) Press the keys in the following sequence: Highlight the R expand. Enter the R Output Expand from the table. c) Wait for the R reading to stabilize. Record the value of R. 4) This completes the amplitude linearity test.
Performance Tests 6. Frequency Accuracy This test measures the frequency accuracy of the lock-in. This tests the accuracy of the frequency counter inside the unit. The counter is used only in external reference mode. The internal oscillator frequency is set by a crystal and has 25 ppm frequency accuracy. Setup We will use the frequency synthesizer to provide the reference signal. Connect the TTL SYNC output of the frequency synthesizer to the Reference input of the lock-in.
Performance Tests 7-16
Performance Tests 7. Phase Accuracy This test measures the phase accuracy of the lock-in. Due to the design of the lock-in, the phase accuracy can be determined by measuring the phase of the internal oscillator Sine Out. Setup Connect the Sine Out to the A input of the lock-in using a 1 meter BNC cable. Do not use any termination. Procedure 1) {PRESET} (Turn the lock-in off and on with the [←] key pressed) 2) Press the keys in the following sequence: [GAIN/TC] Select 24 dB/oct.
Performance Tests 7-18
Performance Tests 8. Sine Output Amplitude Accuracy and Flatness This test measures the amplitude accuracy and frequency response of the internal oscillator Sine Out. Setup We will use the lock-in to measure the Sine Out. Connect the Sine Out to the A input of the lock-in. Procedure 1) {PRESET} (Turn the lock-in off and on with the [←] key pressed) 2) Press the keys in the following sequence: [DISPLAY/SCALE] Highlight the trace number.
Performance Tests c) Press [GAIN/TC] Use the knob to select 1 V. [REF/PHASE] [1] [ENTER] d) Press Enter the frequency from the table. e) Wait for the R reading to stabilize. Record the value of R. f) Repeat steps 4d and 4e for all of the frequencies listed. 5) This completes the sine output amplitude accuracy and frequency response test. Enter the results of this test in the test record at the end of this section.
Performance Tests 9. DC Outputs and Inputs This test measures the DC accuracy of the DC outputs and inputs of the lock-in. Setup We will use the digital voltmeter (DVM) to measure the DC outputs of the lock-in. Then we will use one of the outputs to generate a voltage to measure on the DC inputs. Connect a 50Ω termination to the A input. Procedure 1) {PRESET} (Turn the lock-in off and on with the [←] key pressed) 2) Press [OUTPUT/OFFSET] 3) For the CH1 and CH2 outputs, repeat steps 3a through 3e.
Performance Tests c) For each output voltage in the table below, repeat steps 5d and 5e. Output Voltages -10.000 -5.000 0.000 5.000 10.000 d) Press Enter the voltage from the table. e) Record the DVM reading. 6) Press [DISPLAY/SCALE] Select Input/Output. [AUX OUTPUTS] <1,2,3,4> Select Aux Out 1. 7) For each Aux Input (1,2,3 and 4), repeat steps 7a through 7d. a) Connect Aux Out 1 to Aux Input 1,2,3 or 4. b) For each output voltage in the table above, repeat steps 7c and 7d.
Performance Tests 10. Input Noise This test measures the lock-in input noise. Setup Connect a 50Ω termination to the A input. This grounds the input so the lock-in's own noise is measured. Procedure 1) {PRESET} (Turn the lock-in off and on with the [←] key pressed) 2) Press the keys in the following sequence: [GAIN/TC] Use the knob to select 100 nV. [TRACE/SCAN] (second soft key) Highlight X. Use the knob to select Xn.
Performance Tests 7-24
Page 1 of 4 SR850 Performance Test Record Serial Number Firmware Revision Tested By Date Equipment Used 1. Self Tests Test Power On Tests Keypad Knob Main Memory Video Memory Pass ____ ____ ____ ____ ____ Fail ____ ____ ____ ____ ____ 2. DC Offset Input Coupling AC DC Reading _______ _______ Upper Limit 0.500 mV 0.500 mV Reading _______ Upper Limit 30 µV 3. Common Mode Rejection Frequency 100 Hz 4. Amplitude Accuracy and Flatness Sensitivity 1V 200 mV 100 mV 20 mV 10 mV Calibrator Ampl. 1.
Page 2 of 4 SR850 Performance Test Record 5. Amplitude Linearity Sensitivity 1V Calibrator Ampl. 1.0000 Vrms 100.00 mVrms 10.000 mVrms 4.000 mVrms Lower Limit 0.9900 V 0.0990 V 0.0098 V 0.0038 V Reading _______ _______ _______ _______ Upper Limit 1.0100 V 0.1010 V 0.0102 V 0.0042 V 6. Frequency Accuracy Input Frequency 10 kHz Lower Limit 9.990 kHz Reading _______ Upper Limit 10.010 kHz Lower Limit -1.0 deg -1.0 deg -1.0 deg -1.0 deg Reading _______ _______ _______ _______ Upper Limit +1.
Page 3 of 4 SR850 Performance Test Record 9. DC Outputs and Inputs (continued) Output CH2 Offset -100.00 -50.00 0.00 50.00 100.00 Lower Limit 9.960 V 4.960 V -0.020 V -5.040 V -10.040 V Reading _______ _______ _______ _______ _______ Upper Limit 10.040 V 5.040 V 0.020 V -4.960 V -9.960 V Output AUX1 Voltage -10.000 -5.000 0.000 5.000 10.000 Lower Limit -10.040 V -5.040 V -0.020 V 4.960 V 9.960 V Reading _______ _______ _______ _______ _______ Upper Limit -9.960 V -4.960 V 0.020 V 5.040 V 10.
Page 4 of 4 SR850 Performance Test Record 9. DC Outputs and Inputs (continued) Input AUX1 Voltage -10.000 -5.000 0.000 5.000 10.000 Lower Limit -10.040 V -5.040 V -0.020 V 4.960 V 9.960 V Reading _______ _______ _______ _______ _______ Upper Limit -9.960 V -4.960 V 0.020 V 5.040 V 10.040 V Input AUX2 Voltage -10.000 -5.000 0.000 5.000 10.000 Lower Limit -10.040 V -5.040 V -0.020 V 4.960 V 9.960 V Reading _______ _______ _______ _______ _______ Upper Limit -9.960 V -4.960 V 0.020 V 5.040 V 10.
SR850 SERVICE CAUTION Potentially lethal voltages are present in this instrument. This unit is to be serviced by qualified service personnel only. There are no user serviceable parts inside. Check the LED at the front edge of the power supply board. The unit is safe only if the LED is OFF. If the LED is ON, then voltages are present within the unit - USE CAUTION. Use caution when checking circuits with the power on.
SR850 Service 8-2
SR850 Service Adjusting the DC Offset and Common Mode Rejection 1. The DC Offset and CMRR adjustments affect each other and must be done together. This procedure requires a 50Ω terminator, a BNC Tee and a few BNC cables. A small slotted screwdriver is also required to adjust the potentiometers. 2. Turn the unit ON while holding the [<-] key down. This resets the unit. Let it warm up for at least an hour. 3. Remove the four black screws which secure the top lid. There are two screws on each side.
SR850 Service If the R reading (top display) is less than 1 mV, then proceed to the next step. If the reading is greater than 1 mV, adjust the Voltage Input Offset pot until R is less than 1 mV. 8. Press Rotate the knob to select 1 mV full scale If the R reading is less than 0.02 mV then proceed to the next step. If the reading is greater than 0.02 mV, adjust the Voltage Input Offset pot until R is less than 0.02 mV. 9. Connect the SINE OUT output to both the A and B inputs.
SR850 Service [GAIN/TC] Rotate the knob to select 100 mV full scale If the R reading (top display) is less than 1 mV, then proceed to the next step. If the reading is greater than 1 mV, adjust the Voltage Input Offset pot until R is less than 1 mV. 11. Press Rotate the knob to select 1 mV full scale If the R reading is less than 0.02 mV then proceed to the next step. If the reading is greater than 0.02 mV, adjust the Voltage Input Offset pot until R is less than 0.02 mV. 12.
SR850 Service Adjusting the Notch Filters 1. The Notch filter frequency and depth adjustments must be done together. This procedure requires a BNC cables. A small slotted screwdriver is also required to adjust the potentiometers. 2. Turn the unit ON while holding the [<-] key down. This resets the unit. Let it warm up for at least an hour. 3. Remove the four black screws which secure the top lid. There are two screws on each side. Slide the top lid back about 1/4".
SR850 Service Press [AUTO PHASE] The bottom display should read 0.0°. 7. Press [INPUT/FILTERS] to select Line [GAIN/TC] Rotate the knob to select 50 mV full scale Adjust the Line Notch Depth pot until R (top display) is between 20.0 and 25.0 mV. Then adjust the Line Notch Freq pot to minimize the reading of R AND until θ (bottom display) is EITHER 0° or 180° (within 1°). 8. Now adjust the Line Notch Depth pot until R is less than 1.0 mV 9.
SR850 Service 8-8
CIRCUIT DESCRIPTION Power Supply Board CPU Board Analog Input Board DSP Logic Board CAUTION VIDEO DRIVER AND CRT Always disconnect the power cord and wait at least one minute before opening the unit. Dangerous power supply voltages may be present even after the unit has been unplugged. Potentially lethal voltages are present in this circuit. Do not attempt to service the CRT and Video Driver Board. Refer any service problems to the factory. Check the LED at the front edge of the power supply board.
Circuit Description 9-2
Circuit Description CPU BOARD de-asserted (U805A and U815D) and the processor moves on to the next instruction. The CPU board contains the microprocessor system. All display, front panel, disk, and computer interfaces are on this board. Interrupts generated by peripherals on the CPU board are combined in U505 into a single prioritized interrupt. The highest priority pending interrupt will be encoded on U505's outputs and read via the status port, U608.
Circuit Description address may be read or written. This allows drawing to take place as fast as possible. SPEAKER The speaker is driven by a timer on the 80C186. The timer outputs a square wave which is enabled by U602B and drives the speaker through Q705. Commands and data are sent from the 80C186 to the HD63484 using a DMA channel. This allows the HD63484 to process commands without having to wait for the 80C186 to send them.
Circuit Description POWER SUPPLY BOARD CAUTION: Dangerous voltages are present on this circuit board whenever the instrument is attached to an AC power source and the front panel power switch is "on". The following description refers to the +5V_P supply but describes the +5V_I supply as well. The main pass transistor is Q5. The base of this transistor is controlled so that the emitter will provide a low impedance source of 5 VDC.
Circuit Description 9-6
Circuit Description DSP LOGIC BOARD also sets accuracy. OVERVIEW The DSP LOGIC BOARD takes a digital input from the A/D Converter on the Analog Input Board and performs all of the computations related to the measurement before it is displayed on the screen. This includes generating the digital reference sine wave, demodulating the signal, low-pass filtering the results, and offset and expanding the outputs. The internal oscillator sine output and Aux D/A outputs are generated on this board as well.
Circuit Description ±15V for the op amps. ±5.6V for analog switches and op amps is generated from the ±15V supplies. The reference and sine discriminators use separate ±5V supplies regulated from the ±15V supplies as well. transmit port each cycle. The transmit port operates at twice the frequency of the receive port. The DSP writes to the other channel of each DAC via a pair of parallel-to-serial registers (U504 and U505). DAC OUTPUTS Three of the DAC output channels provide Sine Out, X and Y.
Circuit Description ANALOG INPUT BOARD and frequency adjustment. (60 Hz - depth:P222 and freq:P221 120 Hz - depth:P202 and freq:P201). The 120 Hz notch filter has a configurable gain of either 1 or 3.17. OVERVIEW The Analog Input Board provides the very important link between the user's input signal and the DSP processor. From the front panel BNC, the user's signal passes through a low distortion frontend amplifier, gain stages, notch filters, antialiasing filter, and finally an A/D Converter.
Circuit Description a rate of 256 kHz. One channel is dedicated to the input signal. The other channel reads one of the Aux A/D inputs. The Aux inputs are multiplexed so that each input is read every four cycles. The two digital output streams are buffered by U406 and sent to the DSP board. I/O INTERFACE The Analog Input Board communicates with the CPU Board via its I/O Interface. U504 and U506 are simple latches which hold configuration data for the analog board.
PARTS LIST Power Supply Board Parts List Ref. C1 C2 C3 C4 C5 C6 C7 C8 C9 C 10 C 11 C 12 C 13 C 16 C 17 C 18 C 19 C 20 C 21 C 23 C 24 C 26 C 27 C 28 C 29 C 30 C 31 C 32 C 33 C 34 D2 D3 D4 D5 D6 D7 D8 D9 D 12 D 13 D 15 D 16 D 17 D 18 D 19 D 20 SRS Part No.
Parts List Ref. D 30 D 31 D 32 D 33 D 34 D 35 D 36 D 37 D 38 DS1 JP1 JP2 JP3 JP4 JP5 JP6 PC1 Q3 Q4 Q5 Q6 Q7 Q8 R3 R4 R5 R6 R7 R8 R9 R 10 R 11 R 12 R 13 R 14 R 15 R 16 R 17 R 18 R 19 R 20 R 21 R 30 R 31 R 32 R 33 R 34 R 35 R 36 SRS Part No.
Parts List Ref. R 37 R 38 R 39 R 40 T1 U1 U2 U3 U4 U5 U6 U7 U8 U9 U 10 U 11 U 12 Z0 Z0 Z0 Z0 Z0 Z0 Z0 Z0 Z0 Z1 SRS Part No. 4-00522-407 4-00517-407 4-00522-407 4-00517-407 1-00152-116 3-00039-340 3-00319-340 3-00088-340 3-00088-340 3-00119-329 3-00346-329 3-00346-329 3-00330-329 3-00149-329 3-00141-329 3-00114-329 3-00120-329 0-00089-033 0-00186-021 0-00187-021 0-00231-043 0-00246-043 0-00309-021 0-00316-003 1-00087-131 7-00285-721 0-00158-070 Value 243 3.57K 243 3.
Parts List Ref. C 153 C 154 C 155 C 156 C 157 C 171 C 173 C 180 C 181 C 182 C 183 C 202 C 203 C 204 C 205 C 206 C 207 C 210 C 211 C 235 C 236 C 237 C 238 C 254 C 255 C 260 C 261 C 264 C 265 C 280 C 281 C 282 C 283 C 290 C 301 C 302 C 303 C 305 C 307 C 308 C 309 C 310 C 350 C 351 C 352 C 353 C 381 C 382 C 383 SRS Part No.
Parts List Ref. C 384 C 385 C 386 C 387 C 388 C 389 C 390 C 401 C 402 C 403 C 404 C 406 C 407 C 408 C 409 C 410 C 420 C 421 C 422 C 423 C 424 C 425 C 426 C 427 C 428 C 429 C 430 C 431 C 432 C 433 C 434 C 435 C 450 C 453 C 456 C 459 C 470 C 471 C 601 C 602 C 603 C 604 C 630 C 631 C 650 C 651 C 652 C 653 C 654 SRS Part No.
Parts List Ref. C 655 C 656 C 657 C 658 C 659 C 660 C 661 C 662 C 663 C 664 C 665 C 666 C 667 C 668 C 669 C 670 C 671 CU401 CU402 CX623 D 103 D 104 D 105 D 180 D 181 D 280 D 281 JP301 K 101 K 201 L 101 L 601 N 101 N 102 N 201 N 202 N 301 N 302 N 303 N 304 N 305 N 306 N 420 N 421 N 501 N 502 N 503 N 601 N 602 SRS Part No.
Parts List Ref. N 603 N 604 PC1 Q 101 Q 102 Q 201 R 102 R 103 R 114 R 115 R 116 R 117 R 118 R 119 R 120 R 121 R 130 R 131 R 132 R 133 R 140 R 141 R 142 R 143 R 156 R 157 R 170 R 171 R 172 R 173 R 174 R 175 R 176 R 177 R 178 R 180 R 181 R 201 R 202 R 203 R 204 R 205 R 206 R 207 R 208 R 209 R 210 R 211 R 212 SRS Part No.
Parts List Ref. R 213 R 214 R 215 R 216 R 217 R 221 R 222 R 226 R 227 R 228 R 231 R 232 R 237 R 238 R 239 R 240 R 250 R 251 R 280 R 281 R 290 R 301 R 302 R 303 R 304 R 381 R 382 R 383 R 384 R 385 R 386 R 387 R 388 R 389 R 390 R 401 R 402 R 450 R 451 R 452 R 453 R 470 R 471 R 503 R 601 R 602 R 603 R 604 R 611 SRS Part No.
Parts List Ref. RX623 T 201 TP101 TP102 TP103 TP104 TP105 TP106 TP107 TP108 TP201 TP202 TP203 TP204 TP301 TP302 TP303 TP304 TP401 TP402 TP403 TP404 TP501 TP502 U 101 U 102 U 103 U 104 U 105 U 106 U 107 U 110 U 111 U 120 U 121 U 122 U 180 U 181 U 201 U 202 U 203 U 205 U 206 U 207 U 208 U 209 U 210 U 280 U 281 SRS Part No.
Parts List Ref. U 301 U 302 U 303 U 380 U 381 U 382 U 383 U 401 U 402 U 403 U 404 U 501 U 502 U 503 U 504 U 505 U 601 U 602 U 603 U 604 U 606 U 608 U 609 U 610 U 611 U 612 U 613 U 614 U 621 U 622 U 623 U 630 Z0 Z0 Z0 Z0 Z0 SRS Part No.
Parts List Ref. C 153 C 180 C 181 C 182 C 183 C 201 C 202 C 221 C 222 C 225 C 261 C 281 C 282 C 303 C 311 C 312 C 321 C 322 C 331 C 332 C 341 C 342 C 351 C 361 C 362 C 363 C 371 C 372 C 381 C 382 C 386 C 390 C 391 C 392 C 393 C 394 C 395 C 396 C 397 C 398 C 410 C 411 C 414 C 430 C 431 C 456 C 460 C 461 C 462 SRS Part No.
Parts List Ref. C 463 C 480 C 481 C 482 C 483 C 511 C 512 C 513 C 514 C 515 C 516 C 517 C 520 C 521 C 523 C 524 C 530 C 531 C 540 C 560 C 561 C 562 D 101 D 180 D 181 D 480 D 481 J 101 J 102 JP201 JP221 JP401 K 101 K 102 K 103 K 104 K 105 L 501 N 101 N 102 N 103 N 261 N 401 N 402 N 403 N 404 N 405 N 406 N 501 SRS Part No.
Parts List Ref. P 101 P 102 P 103 P 201 P 202 P 221 P 222 PC1 R 101 R 102 R 103 R 104 R 106 R 107 R 108 R 109 R 110 R 111 R 114 R 115 R 119 R 120 R 123 R 124 R 125 R 126 R 127 R 129 R 130 R 131 R 132 R 133 R 140 R 141 R 150 R 151 R 180 R 181 R 201 R 202 R 203 R 204 R 205 R 207 R 208 R 221 R 222 R 223 R 224 SRS Part No.
Parts List Ref. R 225 R 226 R 227 R 228 R 241 R 242 R 244 R 245 R 246 R 247 R 249 R 252 R 261 R 262 R 299 R 301 R 302 R 303 R 304 R 305 R 306 R 307 R 308 R 309 R 311 R 312 R 313 R 314 R 315 R 321 R 322 R 323 R 324 R 325 R 331 R 332 R 333 R 334 R 335 R 341 R 342 R 343 R 344 R 345 R 351 R 361 R 363 R 364 R 365 SRS Part No.
Parts List Ref. R 371 R 372 R 373 R 374 R 375 R 379 R 381 R 382 R 383 R 384 R 385 R 386 R 387 R 388 R 389 R 391 R 392 R 393 R 394 R 395 R 396 R 397 R 398 R 430 R 431 R 452 R 460 R 461 R 462 R 463 R 480 R 481 R 511 R 512 R 513 R 514 R 515 R 516 R 517 R 518 R 519 R 520 R 540 R 560 SO101 SO102 SO108 SO361 TP101 SRS Part No.
Parts List Ref. TP102 TP103 TP104 TP201 TP301 TP302 TP303 TP405 TP406 TP407 TP408 TP501 TP502 TP503 TP504 TP505 TP506 TP507 U 101 U 102 U 103 U 104 U 105 U 106 U 108 U 109 U 180 U 181 U 201 U 202 U 203 U 204 U 241 U 242 U 243 U 244 U 261 U 301 U 302 U 303 U 304 U 305 U 311 U 321 U 331 U 341 U 361 U 362 U 371 SRS Part No.
Parts List Ref. U 381 U 386 U 391 U 401 U 402 U 403 U 406 U 407 U 480 U 481 U 504 U 506 U 508 U 509 U 510 U 511 U 530 Z0 Z0 Z0 Z0 Z0 SRS Part No.
Parts List Ref. C 902 C 903 C 904 C 905 C 906 C 907 C 908 C 909 C 910 C 1001 C 1002 C 1003 C 1004 C 1005 C 1006 C 1007 C 1008 C 1009 C 1010 C 1011 C 1012 C 1013 C 1014 C 1015 C 1016 C 1017 C 1018 C 1019 C 1020 C 1021 C 1022 C 1023 C 1024 C 1025 C 1026 C 1027 C 1028 C 1029 C 1030 C 1031 C 1032 C 1033 C 1034 C 1035 C 1036 C 1037 C 1038 C 1039 C 1040 SRS Part No.
Parts List Ref. C 1041 C 1042 C 1043 C 1044 CU901 D 100 D 401 D 601 D 602 D 603 D 604 D 605 D 606 D 607 D 608 D 701 D 702 D 703 D 704 D 705 D 810 JP201 JP301 JP302 JP303 JP601 JP602 JP603 JP702 JP801 JP802 JP803 JP901B JP902 JP903 JP1000 JP1002 N 101 N 102 N 501 N 601 N 701 N 801 N 901 N 902 PC1 Q 401 Q 701 Q 702 SRS Part No.
Parts List Ref. Q 703 Q 705 Q 810 Q 811 R 401 R 402 R 502 R 601 R 602 R 701 R 702 R 703 R 704 R 705 R 706 R 707 R 710 R 711 R 712 R 713 R 714 R 801 R 802 R 808 R 809 R 810 R 811 R 812 R 813 R 814 R 901 R 904 R 905 R 911 R 912 R 913 SO101 SO301 SO302 SO303 SO304 SO907 U 101 U 201 U 202 U 203 U 204 U 205 U 206 SRS Part No.
Parts List Ref. U 207 U 208 U 401 U 402 U 403 U 404 U 501 U 502 U 503 U 504 U 505 U 506 U 601 U 602 U 603 U 606 U 607 U 608 U 609 U 610 U 611 U 612 U 701 U 702 U 703 U 704 U 705 U 801 U 802 U 803 U 804 U 805 U 806 U 807 U 808 U 809 U 810 U 811 U 812 U 813 U 814 U 815 U 901 U 902 U 903 U 904 U 905 U 906 U 907 SRS Part No.
Parts List Ref. U 908 X 101 X 801 X 901 X 902 Z0 Z0 Z0 Z0 SRS Part No. 3-00040-340 6-00068-620 6-00069-620 6-00068-620 6-00037-620 0-00126-053 0-00479-055 1-00136-171 1-00137-165 Value 74HC157 24.000 MHZ 13.5168 MHZ 24.000 MHZ 3.6864 MHZ 3-1/2" #24 1.5"X#30 ORA 26 COND 25 PIN IDC Description Integrated Circuit (Thru-hole Pkg) Crystal Crystal Crystal Crystal Wire #24 UL1007 Strip 1/4x1/4 Tin Wire, Other Cable Assembly, Ribbon Connector, D-Sub, Female Chassis Assembly Parts List Ref.
Parts List Ref. Z0 Z0 Z0 Z0 Z0 Z0 Z0 Z0 Z0 Z0 Z0 Z0 Z0 Z0 Z0 Z0 Z0 Z0 Z0 Z0 Z0 Z0 Z0 Z0 Z0 Z0 Z0 Z0 Z0 Z0 Z0 Z0 Z0 Z0 Z0 Z0 Z0 Z0 Z0 Z0 Z0 Z0 Z0 Z0 Z0 Z0 Z0 Z0 Z0 SRS Part No.
Parts List Ref. Z0 Z0 Z0 Z0 Z0 Z0 Z0 Z0 Z0 Z0 Z0 Z0 Z0 Z0 Z0 Z0 Z0 Z0 Z0 Z0 Z0 Z0 Z0 Z0 Z0 Z0 Z0 Z0 Z0 Z0 Z0 Z0 Z0 Z0 Z0 Z0 Z0 Z0 Z0 Z0 Z0 Z0 Z0 Z0 Z0 Z0 Z0 Z0 Z0 SRS Part No.
Parts List Ref. Z0 SRS Part No. 9-00267-917 Value GENERIC Description Product Labels Miscellaneous Parts List Ref. U 301 U 302 U 303 U 304 Z0 Z0 Z0 Z0 Z0 Z0 Z0 Z0 Z0 Z0 Z0 Z0 Z0 Z0 Z0 Z0 Z0 Z0 Z0 SRS Part No.
Parts List NOTICE: Schematics may not show current part numbers or values. Refer to parts list for current part numbers or values.
