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Syscomp Computer Controlled Instruments CGR

1. Vertical Controls f 1 i i H t f f Trigger Controls Channel A 1 E mn t ma 7 seemed eee ze A i i Trigger Mi 1 200mv A x l tigger Mode i i 7 RR FE HSS a Trigger Slope A 9 el L e 2 1 Trigger Source a fa a 2 v L 3 i Manual Tigger Chancel B Trigger Level 155V E ae GC Timebase Controls 1 i paeen 1 t e i 1 ad L 2ms O L E H r f 3 i e 2 XY Mode j E x x Show Measurements Figure 9 Diode Voltage Current Characteristic 6 7 Spectrum Display A complex waveform may be treated as being composed of a number of sinusoid waveforms These sinusoids are of various phases frequencies and amplitudes The description of the magnitude phase and frequency of these various waves is known as the spectrum of the signal by analogy with the spectrum of light Spectrum Analysis or Fourier Analysis is the process of analysing some time domain waveform to find its spectrum We also say that the time domain waveform is converted into a frequency spectrum by means of the Fourier transform Clicking on Tools gt Spectrum Analysis brings up the spectrum analysis display of figure 10 The displayed spectrum in this image is a 10kHz square wave The theory of Fourier Analysis shows that a square wave is composed of a fundamental of magnitude E volts at frequency f 10kHz in this case with the following harmonics 3 m
2. popup window Cancel the popup Select File gt Properties ZA Dn Lh Operate the Connect Using menu to select the COM port that you found previously 8 Select Configure which pops up a Port Settings window Most of the port settings can be left at their default values but the baud rate Bits per Second must be changed to the correct value At this time the correct value is 230400 The correct port settings are Bits per Second 230400 Baud Data bits 8 Parity None Stop Bit 1 Flow Control Hardware RTS CTS Handshaking If you have a version of the scope Tcl program that works correctly with the scope hardware you can verify the baud rate Load that code into a text editor and look for the baud setting Search for a variable baud or a procedure openSerialPort Hit OK and back out to the hyperterminal screen 9 Issue some command from the list in section 15 Type it in followed by the Enter key A good choice is i which should result in a message from the scope indicating its version number 16 2 Linux For manual operation under the Linux operating system you will need to communicate with the hardware us ing a terminal emulator program There are two terminal emulators in common use under Linux seyon and minicom These may not be installed as part of your linux distribution To check whether the program is installed use the which command phiscock panther gt which seyon usr X11R6 bin seyon Se
3. Based Network Analyser at http www syscompdesign com na theory pdf 18 f Syscomp USB Digital Storage Oscilloscope DSO 101 File View Tools Hardware Help Syscomp Digital Storage Oscilloscope Vertical Controls S 11 Channel A Disable Trigger Controls EN Trigger Mode Auto De Single Shot Reset Trigger Slope e L Pus al k 7 Trigger Source la 2 has aa K pnb I re 7 Timebase Controls A adJ B Show Measurements Figure 8 XY Display Mode 6 6 XY Mode The usual oscilloscope display shows a plot of the two signal amplitudes voltage on Channel A and Channel B vs time It is also possible to plot the two voltages against each other Channel A as the X axis and channel B as the Y axis Select View gt XY Mode to enable the XY display The CGR 101 can simultaneously display both the XY display and the conventional voltage time waveforms which is useful in teaching situations and for debugging purposes If you wish to hide the conventional waveforms and just show the XY display disable the individual channels using the Enable Disable button Lissajous Figures When the two signals are sine waves of the same frequency with a phase shift between them the display is as shown in figure 8 This type of looping display is known as a lissajous figure If the two frequencies different but integer multiples of each other then
4. Syscomp CircultGear lol Completing the Syscomp CircuitGear Setup Wizard Setup has finished instaling Syscomp CrcuitGear on your computer The application may be launched by selecting the installed icons Click Finish to exit Setup j Completing the Install Figure 2 Windows Installation Screens i Finished Drivers 4 1 1 10 First Time Operation Using the supplied USB cable or similar one of your own choosing plug the oscilloscope into a computer USB port If you have more than one USB port you can chose any port The green LED on the hardware unit should illuminate and the computer will make its USB boing noise There should be a Syscomp icon on the desktop The exact name will vary but it should be something like Syscomp CircuitGear Start the oscilloscope program by double clicking on this icon Ascreen Unable to Connect to Device Examine Connection Settings appears Click on Yes The Port Settings control panel appears Click on Autodetect The program scans through the available COM ports through 99 If it finds an available port a notification screen will pop up saying something like CGR 101 found on COM6 If it does not find an available COM port try clicking on Autodetect again If this also fails you ll need to set the COM port manually section 4 1 2 below Assuming that the system finds an available COM port click on OK A Port Settings Listi
5. Select Send Line Ends with Line Feeds What this means is that you must send a lt carriage return gt character to terminate the string The lt line feed gt character by itself will not work 5 In the terminal window type the letter 1 followed by lt enter gt The device should identify itself with a string 39 USB Serial Port COM4 Properties 2h xi General Port Settings Driver Details 3 USB Serial Port COMA E Device type Ports COM amp LPT Manufacturer FTDI Location on USB Serial Converter Device status This device is working properly If you are having problems with this device click Troubleshoot to start the troubleshooter Device usage Use this device enable Figure 26 Serial Port Properties 12 1 6 Alternative to Hyperterminal TeraTerm Some versions of the Windows operating system have Hyperterminal installed which can act as a terminal emu lator However Hyperterminal does not provide convenient access to the setup parameters and is difficult to use We installed and used the open source software TeraTerm instead 1 Download and install the TeraTerm software from Sourceforge http en sourceforge jp projects ttssh2 releases This should create a TeraTerm icon on your desktop 2 Plug in the WGM 201 hardware to an unused USB port 3 Start TeraTerm The New Connection window appears TCP IP is selected by default Change the selection to
6. Signout as administrator Sign in as a student Put the app in the dock and boot and make sure it works when the hardware is plugged in Acknowledgements Special thanks to Dorothy Rawek Miles Pierce and Seneca Cunningham Dorothy provided her MacBook for this investigation Miles acted as a beta tester for the Linux install process and supplied important feedback Seneca showed me how to create a shell script using AppleScript 13 Modifying and Running the Source Code When you installed the CGR 101 software the installer created a Source subdirectory which contains the Tcl source code files extension tcl We provide as part of the install an executable which is machine specific ie there are Windows Linux and Mac versions which contains the Tcl interpreter and libraries necessary to run the files in that source code directory The easiest development process is to use that executable to run the source code If you want to change the operation of the code then make a safety copy of the relevant Tcl source code file and edit the source code Tcl file with any text editor You can also run the source code without that executable by executing the command wish main tcl or it s equivalent on your machine in the source code directory If that causes errors the first thing to do is to download the latest version of Tcl from the Activestate website http www activestate com Then try again If there are further error messages conce
7. The unsafe situation of an oscilloscope being used to measure AC line voltage is shown in figure 20 The AC line consists of three connections the hot line the neutral line and the ground wire For safety reasons the neutral and ground are connected together and to an earth ground at the system AC distribution panel The hot and neutral line carry load current in the system normally the ground wire does not carry any current Because the neutral is carrying current and because the neutral wire has resistance at any given point in the system there likely will be a small voltage difference between the neutral and ground wires If the ground wire of the oscilloscope is inadvertently connected to the hot wire of the AC line an extremely large short circuit current will flow through the ground connection Eventually a circuit breaker will open a fuse will blow or the short circuit current will destroy a conductor However until that occurs the short circuit current can be in the order of hundreds of amperes This current will destroy the oscilloscope and computer and the resultant flaming debris may cause injury to nearby living organisms including humans It may also start a fire l0The disadvantages of batteries are a they run down and b they are not current limited A short circuited battery can do significant damage 33 Ground Neutral Hot Ta Y Oscilloscope and Computer H 4 Input 117VAC i Ground a KK
8. 12 proxy x 13 kmem x 15 dialout x 20 gabe peter faxsxi21 voice x 22 and so on Save the file Reboot the computer Execute the groups command You should see that you are a member of the dialout group groups peter dialout Now you should be able to start the instrument code by executing wish main tcl in the directory where main tcl is located The instrument should find and connect to the USB port For security you may want to return the permissions on etc group as they were originally as you noted previously In my case giving groups and users read permission as well sudo chmod 644 etc group lt your password here gt ls 1 etc group rw r r 1 root root 934 2008 05 22 10 17 etc group Special thanks to Gabriel Guillen who loaned me an edubuntu system for this exploration 12 2 7 64 Bit Linux One of the packages in the Syscomp distribution on the CD is the Img package The Img package is a Tcl Tk library that is required for the CGR 101 software Currently those libraries are for a 32 bit linux operating system We are in the process of modifying the distribution to accompodate 64 bit linux but in the meantime here is a workaround Delete the existing Img file The best way to do this is to rename it so that you can back out if this procedure fails Once you ve deleted it try running the software If your Tcl Tk distribution has the correct Img library it should run fine If not download and install
9. 24 default geeko buildhost gcc version 3 3 4 pre 3 3 5 20040809 1 Wed Oct 6 09 16 23 UTC 2004 In this case the kernel is 2 6 8 24 so it contains the FTDI drivers If your kernel version is older than this you may have to upgrade the kernel or install a driver module 2 Install the software per the instructions on the CDROM 3 Determine the serial port used by the USB driver In this step we ll use the dmesg command to determine which serial COM port is being assigned to the oscilloscope when it is plugged in Execute dmesg to get an idea of the most recent kernel messages Using the USB cable connect the scope hardware to a USB port Execute dmesg again and you should see something like this as the last entry in the dmesg printout usb 4 2 new full speed USB device using address 4 usb 4 2 Product USB lt gt Serial Cable usb 4 2 Manufacturer FTDI usb 4 2 SerialNumber 00000001 ftdi_sio 4 2 1 0 FTDI FT232BM Compatible converter detected usb 4 2 FTDI FT232BM Compatible converter now attached to ttyUSBO Unplug the USB cable and run dmesg again and see something like this usb 4 2 USB disconnect address 4 FTDI FT232BM Compatible ttyUSBO FTDI FT232BM Compatible converter now disconnected from ttyUSBO ftdi_sio 4 2 1 0 device disconnected Evidently the USB device is being assigned to device tt yUSBO This shows that the USB device is being recognized by the operating system and assigned to a usb s
10. CSV File 22 05 2009 11 37 AM May 22 2009 11 37 51 csv 13KB CSV File 22 05 2009 11 37 AM E May 22 2009 11 37 57 csv 13KB CSV File 22 05 2009 11 37 AM May 22 2009 11 38 04 csv 13KB CSV File 22 05 2009 11 38 AM E May 22 2009 11 38 11 csv 13KB CSV File 22 05 2009 11 38 AM E May 22 2009 11 38 18 csv 13KB CSV File 22 05 2009 11 38 AM May 22 2009 11 38 25 csv 13KB CSV File 22 05 2009 11 38 AM Figure 29 Directory with Files Check that main tc1 is present in the file list This is the file to execute to start the oscilloscope program Check that the Tcl Interpreter wish is present on your machine which wish If wish is present the which command will show the directory usr bin wish Since usr bin is usually on your PATH wish is present and should execute Now you can execute the DSO 101 software with the command wish main tcl However the oscilloscope software will not connect properly to a USB port until the permissions are corrected That s the next step Configure Permissions on the USB Ports Plugging a Syscomp oscilloscope waveform generator or CircuitGear unit causes the system to create a serial USB port at dev ttyUSBO Notice that this is yew ess bee zero not yew ess bee oh If you have another usb serial device plugged in the number might be some other digit than zero This port has read write permissions for root and for the dialout group It does not have read write permis sions for a lowly user so
11. Calibration The Scope Vertical Calibration panel allows one to set the ver tical scale factor to a precisely correct value This calibration is performed when units are tested so in general it should not be necessary to do this aE ao calibration repeatedly High Range 1V 5V diy Low Flange 60mV S00m div A D Step mvV step A D Step mW step The calibration panel is started from the Tools menu and appears as in figure 5 To operate the calibration procedure ee e Important Check the offsets and re calibrate them if necessary an e Disable Channel B Chen 7 e Set the Channel A vertical gain to 1 V div bg os ty BY La Penne OO SRF e Move the trace vertically until it coincides with one of the display major divisions 0 00592 e Apply a known voltage that is within the display capability of the 00521 channel setting e Adjust the amplitude adjustment slider Channel A High Range TERETE until the trace deflection is exactly correct Save Calibration Values 6 5 Set the Channel A vertical gain to 500mV div Figure 5 Scope Vertical Calibration Apply a known voltage that is within the display capability of the Panel channel setting Adjust the slider Channel A Low Range control until thetrace deflection is exactly correct That completes the gain adjustment for Channel A Repeat the procedure for Channel B Click on Save Calibration Values to Device This transfers the gain values to the EEPRO
12. I 1 E 19 SE To earth Figure 20 AC Line Voltage Furthermore connecting the ground lead of the oscilloscope to the AC neutral line causes another problem it effectively connects the neutral and ground AC lines at that point Now the neutral current has another path and some of it will flow through the oscilloscope and computer ground leads If this current is sufficient it may damage the oscilloscope and computer Notice that this same situation can occur with equipment that is not transformer isolated from the AC line For example some electronic equipment has a direct connection to the AC line so that the chassis is connected directly to the neutral line of the AC system To safely observe the signals in this device with an oscilloscope the equipment must be isolated from the AC line by a transformer The transformer must function as an isolation transformer the secondary winding must not have an electrical connection to either of the primary leads and the transformer must consist of a separate primary and secondary winding An autotransformer common trade name Variac is an adjustable transformer that is often used for adjusting line voltage An auto transformer does not have an independent secondary winding and cannot be used to isolate electronic equipment from the AC line 10 5 Removing the Ground The potential for a short circuit is reduced if the ground connection is removed from the computer However this is extremely danger
13. Set digital output byte to N The parameter N is an 8 bit integer 0 255 E g The command D O 3 would set bits O and 1 of the output port Command Digital Read digital inputs Returns Ix where x is an 8 bit value corresponding to the input byte DEN Frequency 72 kHz 36 kHz 9 kHz 4 5 kHz 1 125 kHz 564 Hz 281 Hz 141 Hz 70 Hz 35 Hz Disabled Digital Set PWM duty cycle to N 255 100 eal N 0 1 2 3 4 5 6 7 8 9 Da Disable auto update of digital inputs on state change Da Disable automatic digital input update on Tevel change Set interrupt mode and arm interrupt D disable rising edge falling edge high level low level The Interrupt returns the charcter when the interrupt condition is met 57 16 Manual Operation The oscilloscope may be operated by sending it commands from a terminal emulator This can be useful for debugging 16 1 Windows The Hyperterminal program that is supplied as part of Windows operating systems is suitable for this 1 To simplify matters it is probably best to unplug any USB devices that are connected 2 Plug the scope hardware into a USB port on the computer 3 Using the steps described in section 12 1 1 determine the COM port that the scope is currently connected to 4 Start Hyperterminal Start gt Programs gt Accessories gt Communications gt Hyperterminal Hyperterminal starts with a Connection Description
14. Syscomp Graphical User Interface GUI program that inter acts with the hardware It also install two Future Technology Devices International FTDI virtual COM port VCP drivers necessary to communicate with the hardware Screen shots of the install procedure are in figure 2 on page 7 1 2 10 11 12 13 Turn on the computer Place the Syscomp install CD in the CD player and close the drive After a brief pause the screen of figure 2 a appears Click Next The screen of figure 2 b appears Click Next The Select Start Menu Folder of figure 2 c appears Click Next The Select Additional Tasks screen of figure 2 d appears We recommend enabling Create a Desktop Icon Click on Create a Desktop Icon until a check mark appears next to it Click Next The Ready to Install screen of figure 2 e appears If you are satisfied with the install directories click on Install Otherwise click Back and revise the necessary entries The Installing screen and progress bar of figure 2 f appears Wait while that completes The USB Device Driver install screen of figure 2 g appears Click Next The Installing drivers screen of figure 2 h appears The Congratulations You are finished installing drivers screen appears figure 2 i Click Finish The Completing the Syscomp Setup Wizard screen appears figure 2 j Click Finish The software is installed You may eject the CD i Setup Syscomp Circui
15. are often applied to the time sequence data prior to transformation into the fre quency domain All window functions taper the data down to zero at its ends Then the discontinuity caused by a finite record length does not affect the shape of the transform The choice of window function depends on the application and all window functions are a compromise of some sort For example some window functions provide very accurate amplitude readings others are best for separating closely spaced frequencies A collection of window functions is shown at http en wikipedia org wiki Window_function The current spectrum analyser includes the rectangular window This window does not shape the time func tion all points on the time record are weighted equally The Hamming Hann and Triangular weighting functions are also available Applications Spectrum analysis has a number of applications in electronics and mechanical engineering e A pure tone has no harmonics and will show up on a spectrum display as one single vertical line Distortion of a sine wave will create additional harmonics Consequently a measure of the magnitude of the harmonics is a measure of the magnitude of the harmonic distortion e In a distortion free linear system two separate input tones single frequencies will emerge as the same two tones at the output If the system is distorting non linear then the system will generate other tones at the sum and difference frequencies o
16. eee SS eee Re 40 Serial Port Properties Advanced se RTE eho e eee oe Chad MoS EES EROS oe 41 Checking that the File has Downloaded o o e o 46 Directory with Fll S 2 5 3 se eee a OEE OEE a e e bee eS 47 USDVICW ii ns aes Sey GS Bees Pa RR eee Se ee ee ee Gee Ee Bee eS 49 Scope Input Compensation Network 2 0 0 000000000 2 eee eee 52 Caution Never connect this instrument to the AC line Doing so may result in personal injury and ex treme damage to the operator the instrument and to an attached computer See section 10 on page 32 File View Tools Hardware Help Connected Oscilloscope Vertical Controls Waveform Generator Channel A X U D MW Al HL W OI Channel B T Disable Sweep Mode Logarithmic Linear i i 1v Triggered 1 i Timebase Controls Trigger Controls e 4 1 Trigger Mode Trigger Slope Trigger Source 4 L 3 ki Singleshor Pus 2 fa 2 v 2ys C Single Shot Reset Manual Trigger Figure 1 CircuitGear Graphical User Interface GUI 1 Overview The Syscomp CircuitGear CGR 101 is a combination of three electronic instruments a two channel digital stor age oscilloscope a waveform generator and a digital input output port Host software can operate the instrument as a spectrum analyser and as a vector network analyser Bode plotter CGR 101 is one of a series of instruments from Sy
17. eee eels eee es 5 4 Display 224s 68nd Beebe Ge PEE ESS OA EEE OM Ede eee dee 6 Additional Features 6 1 Screen T s i u a Aa a a RS Ra ee BA ees a e 6 2 Export to Postscript lt s as sar taw Fe bee eee eee Uae eee se bbw eee 6 3 Scope Offset Calibration s s s aahei a eo aa SS 6 4 Scope Amplitude Calibrati0on RRR KA NR RH R KAA R RR 6 5 Vector NetWork Analyser 4 4 65 ie ow BS edo os OS RS Be ed OPES 66 XYIMGds 2 4 5 44442054 400 223 RS AAA 6 7 Spectrum Display eones eA ee EERE oD EEE Seaweeds eed es 6 8 Data Record Data Logems o ro e si sche on GRR ye YR eR Gee wl ee we a 6 9 Waveform Math 5 402 045 pes babe bP ee be De wea ee ee ee 6 10 Measurements Scree s s osc aos se Gok ae a pe Ele a GOES ee we ae 9 7 Aliasing 8 Waveform Generator 8 1 Setting FreqUENCY s see ee ce ERA RA 8 2 Setting Sweep Limits ee ee 8 3 Sweep Modes s esca baw aS kb eee aA RABE ba he Re R ERS aE eS 8 4 Manual and Automatic Sweep 0 000 ee 8 5 Waveform Selections coi a es RS A ae BO a EE EE a 8 6 NOG 266 bo eh 5 R ee RES eb a AAA Bbw wo ee 8 7 Waveform Format lt lt gt sa r a soarana a a R BO e SL we a OR i 9 Digital Input Output Section 9 1 S Bit Digital Output see oes be bare Pee Eee REP eee bee eb wee eo Pees 9 2 S Bit Digital Inputs 6 e544 ei ZR eb deat dase te bdads anda 9 3 Paret i oc ai ee SBR hw BAS Bh tees Ge ee er Be ade Be ee OP ew al amp Je eG 5 9 4 PWM Pulse Width Modulated Waveform 0000
18. enter the following commands into a terminal window I 2 sudo apt get update sudo apt get install cutecom lrzsz This gets both the CuteCom and 1rzsz packages The latter is not necessary but allows the terminal to sup port zmodem xmodem ymodenm file transfer See https help ubuntu com community Cutecom Now we are ready to test the hardware 1 Ze Plug in the Syscomp hardware unit In a terminal window run the dmesg command Look at the last few lines to confirm the connection port We ll assume ttyUSBO Run cutecom Set up the cutecom terminal emulator characteristics as follows e Device dev ttyUSBO e Baud rate 230400 e Data bits 8 e Stop bits 1 e Parity none e Handshake Hardware Software not selected e Open for Reading writing e Apply settings when opening e CR LF line end e Char delay 1 ms In the Input window enter an i character then press the lt enter gt key In the upper display window you should see a message back from the hardware such as Syscomp CircuitGear V1 4 Then CuteCom is connected to the hardware You can send various messages to the hardware and get responses back testing the commands that are documented elsewhere in this manual Acknowledgement Jan Portegijs told us about CuteCom and gave us the correct settings to connect 12 3 Macintosh The following notes are an edited version of install procedure information kindly provided by Ted Johnson of G
19. for the Syscomp CircuitGear Double click on it The CGR 101 GUI should appear It will probably show Not Connected in red A dialog box will pop up saying Examine hardware settings Click on Yes Examine the hardware settings Select the entry that says cu usbserial xxxx where xxxx is some serial number The gui indicator should turn green and show Connected If the GUI does not connect exit from the gui Unplug the CGR hardware and plug it in again Restart the GUI and this time the hardware should connect properly The program should indicate Connected some activity should be visible on the scope trace the red LED on the scope hardware should flash The unit is operational There s no eject button Steve Jobs doesn t like buttons apparently Right click on the CD icon and select Eject CD 4 2 4 Installing Driver In order to connect the USB Serial driver must be installed on the Mac On some machines this is in place without further intervention However if you followed the previous steps and the hardware still will not connect you may have to download and install the driver 1 4 3 Point your browser at this website http www ftdichip com Drivers VCP htm This is the website for the FTDI Virtual Com Port VCP driver that is needed Find and click on the driver that corresponds to your operating system Mac OSX and processor type x86 or x64 At the time of writing the same driver 2 2 17
20. ftdichip com Drivers VCP htmand download and install the appropriate driver 2 Open Device Manager and maximize the entry Ports COM and LPT Disable the devices that are shown there We know that some Bluetooth devices and a certain Intel program ending appropriately in the phrase SOL can be problems To disable a device right click on the entry in Ports COM and LPT and navigate to the point where you find a disable button 3 Plug in the Syscomp hardware and verify that it appears as an entry under Ports COM and LPT 4 Start the GUI program by double clicking the Syscomp CGR 101 icon on the desktop 5 If the program announces that it cannot connect use the port selection dialog to autodetect the port If the port does not autodetect then select some port manually Select a high ish number something above 15 for example The lower numbers tend to get used first It s not unusual for autodetect to fail and manual to work Once the port is selected you should never have to do that again 6 At that point the device should connect Now if you need other devices you can enable them one by one to find where is the conflict If problems continue please take a screen shot of the expanded Ports COM and LPT and send it to us and we will assist 12 2 Linux These troubleshooting notes are specific to Suse Linux 9 2 but should apply in general They also assume a working knowledge of Linux and its variants Overview If the s
21. is to determine that the computer is capable of running this software To do that 1 Click on the Apple icon in the top left corner of the screen 2 Select About this Mac For example on the local Mac machine the Mac information is e Mac OSX 10 5 6 e 2 4GHz Intel Core 2 Duo e 2GB 667MHz RAM The key items are that the operating system is OSX and it s version is later than 10 2 So the software should run on this machine 4 2 2 GateKeeper Apple have recently August 2012 added a new GateKeeper function to OSX Mountain Lion GateKeeper pre vents downoads of our software so you ll need to disable it while doing the download and install We re currently investigating to see if there is an alternative solution to disabling GateKeeper 4 2 3 Installing Software from the CD 1 Start the Mac 2 Plug in the Syscomp CGR 101 hardware The green LED on the hardware should illuminate 3 Insert the install CD The CGR 101 icon appears on the desktop Open it Open setup htm Clickon Click here for the DMG installer YN DH Nn A Open CircuitGear dmg 8 A screen appears on the desktop showing the Applications folder and the Syscomp CircuitGear unit Drag and drop the Syscomp image onto the Applications folder A progress bar appears and completes Mttp www tcl tk software tcltk platforms html 9 10 11 12 Go to the Applications folder Finder gt Macintosh HD gt Applications Find the entry
22. serial emulated USB connection with the host PC The PC host displays a graphical user interface for the oscilloscope with frequency readouts sliders clickable buttons and various other controls The GUI software is written in the Tcl Tk language The software is open source and entirely in Tcl Tk There are no operating system specific routines The GUI software will operate under Linux Mac or Windows operating systems Tcl Tk is an interpreted language so reading and modifying the source code is straightforward The applications programming interface API is documented so the hardware can be accessed by other computer programs and languages The only requirement is that the language be able to communicate with a serial port 1 5 Software Updates and Help The CircuitGear manual in pdf format is available from the Help menu Clicking on that menu item automati cally invokes Acrobat Reader The software checks the Syscomp website and advises if there is a later version of the software You can do that manually by selecting Check for Update in the Help menu Alternatively you can configure the software to do that automatically every time it starts Select the Check for Updates on Startup menu iteme The Change Log record of changes with each version is available as a Help menu item 1 Scheduled for Fall 2008 2VNA software available Fall 2008 3WaveMaker was developed entirely by John Foster 2 Applications In addition to the us
23. the ActiveState Tcl Tk distribution for 64 bit linux 12 2 8 Running under 64 bit Sidux Debian based Linux The following notes were provided by Radio College of Canada student Gabriel I am currently running the software on a 64 bit Sidux Debian based linux and have noticed that the img library the so files in Imgl3Lin are 32 bit only This prevents the software from running on any 64bit linux systems This can easily be fixed by installing the img package in 64 bit the package name is libtk img and can be installed by running 48 apt get install libtk img on any Debian based OS or by using the default package manager this will work for 32 and 64 bit systems Also the Bwidget package should also be listed as a dependency the package name is bwidget all lower case apt get install bwidget will install it on the system 12 2 9 Device Properties using usbview In general it s not necessary to know anything about the USB properties of the hardware in order to use it However if you do want to inspect those properties usbview is useful It is likely that you will have to install usbview from your Linux distribution disks Once usbview is installed figure 30 you can use it to determine whether a USB device is recognized by the operating system USB As a USB device is plugged and unplugged an entry appears and disappears in the usbview window Clicking on an entry opens up a list of USB properties of the devic
24. the inventor of the language Graphical Applications with Tcl amp Tk 2nd Edition Eric Foster Johnson M amp T Books 1997 Very accessible introductory textbook Tcl Tk Tools Mark Harrison O Reilly 1997 Information on a number of extensions to Tcl Tk 60 Effective Tcl Tk Programming Mark Harrison Michael McLennan Addison Wesley 1998 Techniques of design for Tcl Tk programs Tcl Tk for Programmers Adrian Zimmer IEEE Computer Society 1998 An textbook on Tcl Tk with an academic tone and exercises Tcl Tk for Dummies Tim Webster IDG Books 1997 A useful introduction to Tcl Tk Tcl Tk for Real Programmers Clif Flynt Academic Press 1999 Medium to high level material on Tcl Tk Audio Radio Handbook Section 2 17 2 Pink Noise Generator Editor Martin Giles National Semiconductor 1980 Passive pink noise filter design Available from http www audioxpress com bksprods products bkaa59 htm 61
25. your work Check out our web page for the latest contact information 59 18 Sources of Information 18 1 News Groups comp lang tcl Internet News Group 18 2 Websites http www syscompdesign com Latest information on Syscomp instruments and supporting software Many useful application notes and project descriptions http www tcl tk Home of the Tcl Developer Xchange Pointers to information and software downloads http www activestate com ActiveState is a commercial firm that sells various programming tools provides a home for the Tcl Tk language Free versions of Tcl Tk are available for download from their site 18 3 Paper Scripting Higher Level Programming for the 21st Century John K Ousterhout IEEE Computer magazine March 1998 Currently at http home pacbell net ouster scripting html Also at http www tcl tk doc scripting htm The definitive paper on Tcl Tk and scripting languages in general Ousterhoot shows a Table of Applications which have been coded in Tcl Tk and in the C language and the relative effort and time required for each imple mentation 18 4 Textbooks Practical Programming in Tcl and Tk 4th Edition Brent B Welch amp Ken Jones with Jeffery Hobbs Prentice Hall PTR 2003 The definitive reference for Tcl and Tk Includes CDROM with Tcl and examples Tcl and the Tk Toolkit John K Ousterhout Addison Wesley 1994 Now somewhat dated but a still useful introduction to Tcl Tk by
26. 00002 ee eee 95 External Trpger ii Z fee A REESE AR EG RG HOR aS 9 6 Kear Panel Connector lt 20445 40 26 a ene bebe ane RE R N 9 7 Rear Panel Connector Mating Plug w a 10 Safe Measurement Technique 10 1 Floating PowerSupply ss credes ereere ee orar dr bee eee ee Os 10 2 Grounded Power Supply 0 0 0000 eee R R ee 10 3 Battery and AC Adaptor Power Supplies 2 2 a ee 10 4 Russian Roulette and AC Line Voltage 2 ee 10 5 Removing the Ground ss c s eh Soe eee Bors a pO ie OR BA a 11 12 12 12 13 14 14 14 15 16 16 19 20 24 25 25 26 27 27 27 27 27 28 28 28 12 Troubleshooting 12 1 Microsoft WindOWS s sea A 45 eee CEES a EER Eee EERE eG OE He 12 1 1 Manually Assigning a COM Port Number in Windows XP 12 1 2 Checking the Installed Files lt s eu a R Ra RR eea ee R R 12 1 3 Obtaining Details of the USB Serial Port aoaaa 12 1 4 Adjusting the COM Port Selection s sicc R RR RRR ee e 12 1 5 Checking the Connection with Hyperterminal 2 0 12 1 6 Alternative to Hyperterminal Tera Term esme kaapua 1217 Windows T Notes cios o Se ee ae Pe A eee we ba 1225 R amp ge oon os Ge e SGA ee Tee Td a ok Se GE HCA Boe Bm aE aca 12 2 1 Manually Changing Device Port Permissions o e e e 12 2 2 Setting Default Port Permissions to User Mode Suse9 2 12 2 3 Setting Default Port Permission
27. 1 Choose a suitable directory into which the data should be stored Change to that directory in the Choose Export Directory entry widget The Log Interval sets the time between records For example if this is set to 5 a new data record is cap tured every 5 seconds Click on Start Logging and the files will be generated The Log Count shows how many records have been stored The data recorder creates a separate file for each data record A typical directory record is shown in figure 11 Each file name is in the month day year hour minute secondformat Click on Stop Logging to halt data logging The captured data is in csv comma separated values format which can be directly loaded into a spreadsheet such as Open Office Calc or Microsoft Ex cel An exerpt of the file is shown below There are 512 data entries in the file Time s Channel A V Channel B V 0 0 0 1042 0 0 56e 005 0 1563 0 0521 12e 005 0 1563 0 0521 68e 005 0 1042 0 0521 0001024 0 1042 0 0 000128 0 1042 0 0 0001536 0 1042 0 0 0001792 0 1042 0 0521 0002048 0 1042 0002304 0 1042 000256 0 1042 0 0002816 0 1042 0 0 0 0 C C C9 CC CC CO d Gn M 24 Data AA Stop a Log Count Log Period z Recorder Status dle Choose Export TEN Files Syscomp CGR101 1 0 Sourcd El E E E Sone i E May 22 2009 11 37 7 30 csv May 22 2009 11 37 37 csv E May 22 2009 11 37 44 csv E May
28. 1 R2 is accompanied by a capacitive voltage divider VC1 C1 The capacitive divider must be adjusted to have the same division ratio as the resistors This is accomplished by adjusting VC1 To do so remove the circuit board from its plastic case Connect it to the computer via its USB cable and start the host software Apply a square wave input signal to one of the scope channels Adjust the magnitude of the square wave such that it makes a suitable display Adjust the oscilloscope timebase such that the leading edge of the square wave is visible The two variable capacitors are relatively large square components that rise above the other components on the board The current versions have orange casings On the current design they are designated C61 for Channel A and C81 for Channel B Locate the variable capacitor on the circuit that corresponds to the input channel with the signal With a tiny screwdriver adjust that variable capacitor until the square wave shows the fastest possible rise time without overshoot It is best to use a screwdriver with an insulated shaft because a non insulated screwdriver will connect human body capacitance into the circuit which affects its operation If the screwdriver is not insulated make an adjustment and then remove the screwdriver to see the effect Repeat the same procedure with the second oscilloscope channel Reassemble the unit back in its case If you are using a x10 oscilloscope probe the input capacit
29. 22 2009 11 37 51 csv E May 22 2009 11 37 57 csv May 22 2009 11 38 04 csw May 22 2009 11 38 11 csv E May 22 2009 11 38 18 csv El May 22 2009 11 38 25 csv Figure 11 Data Recorder Panel 13 KB 13 KB 13 KB 13 KB 13 KB 13 KB 13 KB 13 KB 13 KB 13 KB 13 KB 13 KB 13 KB 13 KB CSV File CSV File CSV File CSV File CSV File CSV File CSV File CSV File CSV File CSV File CSV File CSV File CSV File CSV File 6 9 Waveform Math HES 1919 Mam C Add A B C Subtract A B Multiply A B ej el R lt hana a Toolbox b Addition c Multiplication Figure 12 Waveform Math Tool The math toolbox generates a waveform display that is some function of the waveforms on Channel A and Channel B Clicking on Tools gt Math Toolbox brings up the display of figure 12 a At this time there are three math functions Add A B Subtract A B and Multiply A x B The software does a point by point math operation on the input waveforms and generates a display of the result on the main display The vertical scale factor control 2 volts div in figure 12 can be used to adjust the displayed magnitude of the result The display of figure 12 b shows the addition of two sine waves Figure 12 b shows multiplication In the case of multiplication where one waveform is proportional to voltage and the other to current then the product is a waveform of power Subtraction of tw
30. M memory in the hardware This does not affect the factory default settings If you decide that you wish to return to the factory default settings click on Restore Defaults The hardware will retrieve the factory settings from the EEPROM memory in the hardware Vector Network Analyser An electrical network such as a lowpass filter is charac terized by its amplitude and phase response The ampli Pa a EE E tude response is a plot against frequency of the gain of I the network the ratio of output signal amplitude to in Generator Scope phase and input phase The test signal is a sine wave that 1s swept over a range of frequencies taking care not to Scope put signal amplitude The phase response is a plot of the Output Channel A Channel B phase of the network the difference between the output Input Input Test Network overload the network As part of their AC Circuits lab electrical engineer ing students are required to plot these response curves Figure 6 Network Analyser Wiring by hand This is a very tedious process Each point in the plot requires setting the generator frequency reading the input signal amplitude reading the output signal amplitude reading the output signal phase and plotting the result The CGR 101 vector network analyser does this automatically over a range of 1Hz to 1MHz or some part thereof This makes it practical to explore the effect 16 faq Syscomp CircuitGear 15 x F
31. O entry phiscock panther dev gt ls 1 ttyUSBO crw rw 1 root uucp 188 0 2008 04 20 12 57 ttyUSBO The uucp group have read write permission to this device so the permanent solution is to add uucp as one of your groups In Suse 10 3 this is done from Computer gt Control Center gt Open Administrator Settings YOU l need to enter the root password Then goto Security and Users gt User Management gt User and Group Administration Select the user that s you and click on Edit This brings up the Existing Local User page Click on Details Under Groups check off uucp Log out and log back in or restart the computer You should now be able to access the USB port without having to change its permissions 12 2 4 Setting Default Port Permissions to User Mode Fedora Core 6 This note applies to Fedora Core 6 kernel 2 6 19 1 2911 fc6 Look in etc udev rules d 50 udev rules for the line KERNEL tty A Z NAME k GROUP uucp MODE 0660 Change the mode value to 0666 12 2 5 Running the Program 1 Change to the directory where the program resides The wish interpreter is required to run the tcl program It is normally included with a Linux distribution so it is probably present on your system You can find out by issuing the which command phiscock linux which wish usr bin wish If this doesn t turn it up use the find command starting at the root directory If it is on th
32. OM for more information on how to determine which USB serial port is being used by the device with help from the dmesg command 4 3 2 Optional Running the GUI from Source You can execute the source code directly using the Tcl interpreter wish The Tcl Tk language must be installed on your machine This language is commonly included with most Linux distributions If it is not installed on your machine visit ActiveState the maintainers of the Tcl language to download it You can determine if Tcl Tk is installed on your system by executing the command which wish See also section 13 on page 51 For information on the Tcl language see the application note on the Syscomp website Hello Button 5 Oscilloscope Basic Controls The oscilloscope Graphical User Interface GUI is shown in figure 3 The exact design of the GUI is subject to change and development as features are added but figure 3 will provide some guidance Many of the scope controls are similar in function to those of the classic analog oscilloscope Other controls are unique to the CGR 101 They provide functions such as pre trigger display that are only possible in a digital oscilloscope The scope controls divide into various groups amplitude timebase triggering and display 11 File View Tools Harcware Help Bicones Oscilloscope Vertical Controls 116 22 ns 1 L 1 sv 1124 8 6 MHz 1 L Channel B T Disable A
33. Serial 4 On that same window select Port In this case it shows COM3 and COM5 USB Serial Port Select COMS Click on OK Window closes 5 Select the menuitem Setup gt Serial Port The port has been selected no need to change that Set the Baud Rate to 230400 Set Data Bits to 8 Set Stop Bits to 1 Set Parity to None Set Flow Control to Hardware Click on OK Window closes 40 f Advanced Settings for COM4 M L T L L L Figure 27 Serial Port Properties Advanced 6 Select the menu item Setup gt Terminal Change the New line Receive to CR LF Change the New line Transmit to CR LF Click on OK Window closes 7 In the main terminal window type the letter i followed by the Return key You should see a message something like Syscomp Advanced Waveform Generator V1 0 1 0 If so you are now connected and can issue commands to the generator Notice that all commands are terminated by the Return key 8 Example The command A 128 sets the amplitude to 5 volts Example The command W 1 sets the waveform to Triangle 41 12 1 7 Windows 7 Notes The hardware and software will work correctly under 32 bit and 64 bit versions of Windows 7 operating systems However we have found that certain other serial usb devices can interfere with the operation These hints may help 1 Make sure you have the appropriate 32 bit or 64 bit FTDI Virtual COM Port driver installed for this machine Go to http www
34. Syscomp Computer Controlled Instruments CGR 101 CircuitGear Manual Syscomp Electronic Design Limited http www syscompdesign com Revision 1 15 July 21 2013 CIRCUITGERR Revision History Version Date Notes 1 00 September 2008 First revision 1 01 October 2008 Added VNA XY Plot Spectrum Analysis 1 02 May 2009 Added reference to Ubuntu and Mac installs Corrected errors Added pinout diagram for rear panel connector Added data record Added hyperterminal note 1 03 June 2009 Updated network analyser description 1 04 July 2009 Minor corrections 1 05 Sept 2009 Expanded Mac and Linux install notes 1 06 Oct 2009 Added rear connector info exernal trigger waveform math offset cali bration and amplitude calibration 1 07 December 2009 Corrected Mac OS X install procedure 1 08 January 2010 Documented new GUI V1 13 installation procedures Reorganized Install and Troubleshooting 1 09 May 2010 Documented V1 14 software new features 1 10 October 2010 Added Mac multiuser install info Added instructions for using CuteCom terminal emulator under Linux 1 11 March 2011 Multiple small corrections and additions Added notes on Win 7 install 1 12 April 2011 Minor corrections 1 13 August 2012 Added info on setting debug level Added VNA Linear and Narrow Band Sweep Added Digital I O Undock feature Added Mac FTDI driver install procedure Added note on Mac GateKeeper 1 14 July 2013 Added note on rear panel connector 1 15 Clarified Modi
35. Timebase Controls Trigger Controls Trigge Mode Trigger Slope Trigger Source r i 0 al alia E F3 Single Shol Reset Manual Trigger 1 U Figure 3 Oscilloscope GUI 5 1 Amplitude There are two input channels A and B each with identical controls e Disable Click on this button to disable display of the corresponding waveform This is useful to reduce clutter on the display e Scale Sets the vertical scale factor of the display between 50mV per division and 5 volts per division in the traditional oscilloscope 1 2 5 sequence The amplitude may be read off the display by measuring the number of divisions and multiplying by the scale factor Alternatively the display amplitude cursors may be used see display below Changes to the scale control adjust the sensitivity of the front end of the oscilloscope adjust the preamp gain and change the software scale factor e Option This menu on each channel accesses the Channel Invert functionandthe Channel Disable function There are on screen indicators of Channel Disable and Channel Invert 5 2 Timebase The Main Time Base MTB can be varied between 50nsec division and 100msec division in the traditional oscil loscope 1 2 5 sequence 5 3 Triggering In order to present a stable waveform display each display update must start at the same point on a waveform The trigger functions determine how that trigger point on the waveform is selected The trigger control
36. agnitude at frequency 3f E 5 magnitude at frequency 5f E 7 magnitude at frequency 7 f and so on The spectrum display shows this pattern Each vertical line represents one of these frequency components The height of the line is proportional to the magnitude of that particular component The horizontal axis is a linear scale of frequency with zero frequency DC at the left edge The vertical cursor can be dragged horizontally to determine the frequency and magnitude of a component of the spectrum The spectrum display and main waveform display are active at the same time allowing one to simultaneously observe a waveform in the time domain and frequency domain Interpreting the Display Because of fundamental limitations in a sampled data system it is possible for the display to be misleading Here are some important points to keep in mind when using spectrum analysis based on digital methods e The Effective Sampling Rate is shown in a readout at the bottom right corner of the spectrum display This is important the sampling rate must be at least twice the frequencies being analysed to avoid aliasing Put another way there must not be frequency components above the Nyquist rate which is half the sampling rate In the example shown in figure 10 the sample rate is 200kHz The frequency components range from 10kHz to 90kHz below the Nyquist rate of 100kHz e A sweeping type analog spectrum analyser moves a bandpass filter across a r
37. al the scope uses the trigger signal to synchronize waveform capture If there is no trigger signal the scope hardware waits for a period of time and then generates a trigger signal internally That way there are periodic updates to the waveform display even if triggering is not occurring from an input waveform In general the most convenient position is Auto However there are two situations where Normal triggering is necessary For very low frequency waveforms the trigger signals occur infrequently If Auto triggering is enabled the scope will decide that trigger signals are not present and generate them internally This is not what is wanted the scope should wait for a waveform trigger signal If the scope is being used to capture a single shot event then it should not trigger itself it should wait for a waveform trigger signal regardless of how long it takes for that trigger signal to occur In the Single position the scope waits for a trigger signal This is known as the Armed state When a trigger signal occurs the software captures and displays that waveform and disables further triggers The Single Shot Reset button clears the display and returns the scope to the Armed state Trigger Slope The trigger slope control selects a positive going or negative going slope at the trigger point This allows one to trigger off the leading or trailing edge of a positive pulse waveform for example Trigger Source The trigger signal
38. ance of the scope channels will have changed slightly You will need to adjust a x10 probe for best square wave response If the probe is a x1 x10 switchable unit ensure that the probe is switched to the x10 position Attach it to one of the channels Connect the probe to a square wave source such as the CGR 101 generator output Find the compensation adjustment screw on the scope probe In the economy probes we sell the screw adjust is red and located in the base of the probe cable near the BNC connector In the professional probe we sell the screw adjust is yellow and located in the probe near the handle Adjust this screw for best square wave response 15 Oscilloscope Commands These commands are low level instructions to the scope hardware The commands and where relevant messages back from the hardware are ASCII strings so that they can be generated easily by software or a human operator There are two situations where the interface commands may be useful e The scope hardware may be operated directly from a terminal emulator program such as Hyperterminal under Windows Minicom or Seyon under Linux e The commands must be known to create a scope control program with different functionality For example a program could be created to sweep the read the oscilloscope and plot the results on a strip chart type of display This new program needs to issue commands to the hardware 52 Should you decide to attempt such a project the Tcl sou
39. ange of frequencies to de termine the spectrum A digital spectrum analyser such as this one divides up the frequency range into a number of bins and then measures the energy in those bins SHarmonics of the square wave extend to much higher frequencies but we assume their amplitude is small enough to be ignored 20 Frequency Spectrum nn as Frequency Spectrum Analysis Y 3 Vertical Scale FFT Source S FFT Window anne tea Rate pas Linear Channels 2 Rectangula Number of anne tea Logarithmic T Channel B 31 7 kHz Figure 10 Square Wave Spectrum The main oscilloscope display of the CGR 101 is 500 points This is padded to 512 points by appending zeros to the waveform record As a result there are 256 frequency bins when using the main oscilloscope display The centre frequency of each of these bins may not coincide exactly with the frequency components present If that is the case then the displayed amplitude will be incorrect and should only be regarded as an approx imation of the true situation As the readout cursor is dragged higher in frequency it jumps from bin to bin reading out the centre frequency of each bin A given frequency component may not be centred in its bin so the frequency readout will be only approximate For example in figure 10 the square wave frequency generated by a Syscomp WGM 101 waveform generator is at a frequency 10kHz to within a fraction of a Hz The 9th
40. applies to both types of processors Click on that driver number A window will open allowing you to download the driver You should now have a DMG version of the driver on your desktop Double click on that file to run it This will install the driver When that completes restart the Syscomp GUI software as you did before Go to the Applications folder Finder gt Macintosh HD gt Applications Find the entry for the Syscomp CircuitGear Double click on it The CGR 101 GUI should appear It will probably show Not Connected in red A dialog box will pop up saying Examine hardware settings Click on Yes Examine the hardware settings Select the entry that says cu usbserial xxxx where xxxx is some serial number The gui indicator should turn green and show Connected If the GUI does not connect exit from the GUI Unplug the CGR hardware and plug it in again Restart the GUI and this time the hardware should connect properly The program should indicate Connected some activity should be visible on the scope trace the red LED on the scope hardware should flash The unit is operational Linux Installation Insert the CD into a drive An image of the drive should appear on the computer display Change to the Source directory Copy all files and folders from the Source directory on the CDROM in to a suitable directory on your machine for example home yourname Syscomp CGR101 10 3 Copy the
41. appropriate binary file from the Source bin directory into the folder you selected or execute the appropriate shell script in the Source directory For example sh Install Linux 32 bit sh or cp home yourname Syscomp CGR101 bin linux linux_ix86 CGR101 linux x86 home yourname Syscomp CGR101 The above command should be executed on one line 4 Execute the binary executable to start the software For example use these two commands cd home yourname Syscomp CGR101 CGR101 1linux x86 4 3 1 Hardware Installation 1 Plug the hardware device into an available USB port 2 Run the program dmesg to show which serial port the instrument has been attached For example dev t tyUSBO 3 Start the binary executable the GUI Graphical User Interface as described above 4 On the GUI use the Hardware gt Port Settings menu in the instrument software GUI to manually connect to the serial port we found using dmesg eg dev ttyUSBO 5 The GUI should indicate Connected and the oscilloscope trace should show activity Note that currently Linux assigns USB serial ports in the order in which the instruments are plugged in You may have to manually reassign the port settings in the GUI intrumentation software if multiple Syscomp Instruments are used simultaneously Use dmesg each time you attach an instrument to the computer to determine its serial port assignment Refer to the technical manual in the Document at ion folder of the CDR
42. are just as if it was accessing a device connected to the host serial port This is orders of magnitude simpler than dealing with USB which is extremely complicated We refer to this as a USB serial interface The USB serial has major advantages over the traditional serial port First the data transfer rate is much faster especially using the USB2 0 standard Furthermore power is transmitted from the host to the hardware over the USB cable so that an AC adaptor is not needed Third the USB system handles enumeration automati cally so that multiple devices are accessed correctly without manual configuration Under Windows the FTDI USB serial drivers are automatically loaded by the Install program so the user should not normally be required to intervene Under Linux the FTDI drivers are included in the Linux kernel since 2 4 so they do not need to be installed under Linux When a USB serial device is plugged into the host computer for the first time the host USB system detects a new device and allocates it to a serial port In Windows this is a COM port In Linux this is a device such as dev ttyUSBO Thereafter the operating system always associates that hardware with that serial port even if it is plugged into a different USB port In Linux the default permission of the dev tt yUSBx ports is set for root access only so the permissions must be changed as described under 12 2 The x in dev tt yUSBx represents a number for a ttyUSB por
43. ation of your home directory vs system directories such as etc and dev You must know how the 1s command works Download and Unpack the Software gt eelab File Browser tile Edit View Gn Hookmarks Help e 0 S Back Up Reload Horre Comptter Search EIO ese a Places v x O peter gj Desctop File System Floppy Prive af Network Servers Y Tras TE Documents Music Pictures Videos DSOICIVIS1O WEM 10 ly p lin 7ip Figure 28 Checking that the File has Downloaded The software is available for download from the Syscomp website www syscompdesign com download htm Use the mkdir command to reate a directory on your computer In my case this directory is home peter eelab 46 Click on the file Linux x86bin to download it to your computer check that it is in the ee lab directory figure 28 The file that you downloaded is an archive from which you must extract the files Right click on the file and selectExtract Here A directory is created with the extracted files in it Change to that directory and examine the contents figure 29 L 13KB CSV File 22 05 2009 11 36 AM E 13KB CSV File 22 05 2009 11 37 AM E 13KB CSV File 22 05 2009 11 37 AM E 13KB CSV File 22 05 2009 11 37 AM E 13KB CSV File 22 05 2009 11 37 AM May 22 2009 11 37 30 csv 13KB CSV File 22 05 2009 11 37 AM E May 22 2009 11 37 37 csv 13KB CSV File 22 05 2009 11 37 AM E May 22 2009 11 37 44 csv 13KB
44. c com Distributed by Active Tech Electronics in Canada http www activel23 com Another suitable connector is this one 30 Key Interrupt GND Digital Inputs 0 1 2 3 4 5 6 7 6 8 O O O O O O 5 7 9 0 1 2 3 4 5 6 7 Digital Outputs PWM Out Ext Trig In CircuitGear Rear Panel Connector View toward rear panel Figure 17 CircuitGear Rear Panel Connector Pinout 3M part D89120 0131HK Digikey part MKC20E ND 20 position 2 row 0 1 2 54mm contact spacing ates with 20 way 0 050 spacing flat cable Polarizing key Centre bump Contacts 10u gold plate Digikey price 0 69 Mating strain relief for this connector 3M part D3448 89120 Digikey part MESR20 ND Available from Digikey http www digikey com Any flat cable with 0 050 conductor spacing that will mate with IDC Insulation displacement connector should be suitable for use with these plugs For example 3M 3302 Series Digikey part MCM 20M 5 ND 5 foot length 10 colour repeat clear carrier Digikey price 7 50 The installation of an IDC connector onto flat cable is described here http hubbard engr scu edu embedded guide ribbon Patch Cords There exist some very handy patch cords which are socket socket socket pin and pin pin The size of the socket is such that it fits over an individual pin on the rear panel connector Then a socket pin cable can connect a rear panel connector pin into a protoboard A socket soc
45. click on it to obtain the System Properties screen of figure 24 Double click on the Hardware tab to obtain the Device Manager screen of figure 25 36 L My Computer File Edit View Favorites Tools Help eL G FS Y O sean 1 Folders is E x 1 E Files Stored on This Computer GA Shared Documents File Folder Peter Hiscocks s File Folder Hard Disk Drives SP ACER C Local Disk 26 6 GB 19 0 GB S ACERDATA D Local Disk 8 99 GB 8 99 GB Devices with Removable Storage 080D50101 E CD Drive 14 0 MB O bytes Other G Control Panel System Folder Figure 21 My Computer Provides options Foar amp Control Panel Ele Edt View Favorites Tools help a OG O PD Osea Pes gt amp 19 FA B comments ACA Filter Configures speaker configuration and other parameters of AC3 decoder fiter Accessibility Options Adjust your computer settings for vision hearing and mobility SE Add Hardware Installs and troubleshoots hardware T Add or Remove Programs Install or remove programs and Windows components 9 Administrative Tools Configure administrative settings for your computer A Automatic Updates Set up Windows to automatically deliver important updates Date and Time Set the date time and time zone for your computer Sh Display Change the appearance of your desktop such as the background screen s Folder Options Customize the display of files and Folders change file associati
46. dware To slow this down put the scope in Manual Trigger mode Now each time you hit the manual trigger button the debug screen will show the commands that were sent to the scope hardware Now you can change control settings on the scope GUI and see the corresponding commands as they are sent to the scope hardware For example move the trigger level cursor on the scope screen and you will see a series of trigger level commands like T55 T43 T27 being sent to the hardware Similarily changing the vertical preamplifier gain settings to show the corresponding hardware commands Regarding the oscilloscope operation For normal triggering the host PC issues a request for an update When a trigger occurs the hardware acquires the waveform and sends it to the host The host receives it on an asynchronous basis using the fi leevent command That command then processes the data The waveform data is 1K samples per channel times two channels times two bytes per sample equals 4k bytes Debug Level If you d like to see more detail of the commands being sent to the hardware you can turn on a debugging flag in the software Here s the way to do that on a Windows system e Open the source file directory which is something like C Program Files Syscomp CGR101 1 17 source e Load the file main tcl into notepad e find the line near the beginning of the file that says set debugLevel 0 Change this to set debugLevel 1 Save the file e R
47. e USB Viewer EHCI Host Controller Waveform Generator WGM 101 HCI Host Controller Waveform Generator WGM 10 HCI Host Controller USB lt gt Serial Cable HCI Host Controller UHCI Host Controller USB P5 2 Optical Mouse Manufacturer Syscomp Serial Number WGO36R3J Speed 12Mb s full USB Version 2 00 Device Class DO gt ifc Device Subclass 00 Device Protocol 00 Maximum Default Endpoint Size 8 Number of Configurations 1 Vendor Id 0403 Product Id 6001 Revision Number 4 00 Config Number 1 Number of Interfaces 1 Attributes 60 MaxPower Needed 400mA Interface Number 0 Name ftdi_sio Alternate Number 0 Class ff vend Sub Class 0 Protocol 0 Number of Endpoints 2 Endpoint Address 81 Direction in Attribute 2 Type Bulk Max Packet Size 64 Interval Oms Endpoint Address 02 Direction out Refresh Configure About Close Figure 30 Usbview Notice that usbview does not indicate the serial port dev ttyUSB2 or whatever that the operating system has assigned to this device You must use dmesg for that purpose 12 2 10 Terminal Connection under Linux It can be useful to connect to the hardware via a terminal emulator to check the operation of the hardware We used the program Cutecom under Ubuntu Linux It should be possible to install Cutecom under other versions of Linux 49 To install Cut ecom under Ubuntu Linux
48. e input and output waveforms which should be sine waves If the signals show clipping reduce the signal amplitude The Start button initiates a frequency sweep Sweeping is slow at low frequencies and speeds up as the frequency increases The display autoscales that is tries to select a scale that just fills the display e The amplitude dynamic range of the VNA is in excess of 50db The VNA automatically adjusts the input signal attenuators of the oscilloscope section to obtain the best possible signal noise ratio without clipping It also uses the full 10 bit range of the oscilloscope A D converters In the frequency response plot of figure 7 the amplitude and phase plots become erratic at high frequencies This occurs because the output signal from the low pass filter is extremely small in that region e The amplitude and phase information may be saved to a csv format data file which can be loaded into Matlab or a spreadsheet With the VNA operational select Tools gt Export Waveform CSV Linear and Narrow Band Sweep It is possible to set the analysis to a narrow range of frequencies to characterize narrow band filters and piezoelec tric crystals e Click on the numeric readout for Start Frequency An entry window appears Enter the starting frequency in Hz Click on the numeric readout for End Frequency An entry window appears Enter the ending fre quency in Hz Click on the numeric readout for Frequency Step A
49. e manually adjusted continuously without range switching over that entire range or some subrange For automatic sweep a Vector Network Analyser VNA aka Bode Plotter program is available The VNA software operates the oscilloscope and generator sections in concert to sweep a network over a specified range and plot the amplitude and phase of the response The usual sine square triangle and sawtooth waveforms are supplied with the instrument The generator can also load and produce an arbitrary waveform A GUI based program WaveMaker is available for the construction of arbitrary waveforms WaveMaker was originally a separate program It is now available under the Tools menu The WaveMaker manual is available as a menu item from the main WaveMaker screen The generator includes a random noise source with white spectrum useable to 2MHz 1 3 Digital Input Output The digital I O section includes an 8 bit output port and 8 bit input port Outputs are controlled by 8 GUI buttons Inputs are displayed on 8 GUI indicators In addition there is an nterrupt indicator input and PWM variable frequency output In combination these controls form the basis for digital controls and displays for basic digital exercises or more advanced control systems 1 4 General The hardware is in a pocket sized package that can easily be carried in a student backpack or with a laptop computer Power and control signals are provided to the hardware via a single
50. e system then add that location to your path 12Kindly supplied to us by John Foster 45 phiscock linux lt much deleted gt usr bin wish 2 Start wish phiscock linux find name wish eelab demos gt wish 3 A new small window will appear This is the container for any program that wish executes The cursor remains where the wish command was run 4 Click in that window and run the command source main tcl using the correct name for the oscilloscope program The oscilloscope GUI should now run correctly There are many other ways to start the program For example the command wish scope 101 tcl substitute the correct name of the tcl program can be used As well the KDE and Gnome graphical user interfaces be used to set up an icon on the desktop Then clicking on that icon will start the program 12 2 6 Ubuntu Linux Install This sectiondescribes how to install the DSO 101 oscilloscope software on a Ubuntu Linux system This proce dure was tested on an Edubuntu system Hardy Heron April 2008 Similar instructions apply to installation of the WGM 101 Waveform Generator and CGR 101 CircuitGear with the corresponding file names This application note assumes some familiarity with Linux Specifically you must know how to use an editor to modify files You should know how permissions work and how to use the chmod command to change them You should have some familiarity with the directory structure and the loc
51. eable to limit the spectrum to the audio range to avoid damage to amplifiers and tweeter loudspeakers 28 is formatted correctly Then on the graphical user interface for the CGR 101 load the file into the generator by selecting the Custom waveform 9 Digital Input Output Section Interrupt PWM Disable y Digital Outputs Digital Inputs Figure 16 Digital Controls The CircuitGear digital controls are shown in figure 16 These input and output lines can be operated from the GUI controls in figure 16 or they may be controlled by software that communicates with the CircuitGear API applications program interface section 15 2 on page 54 Undocking the Digital I O Controls On a netbook computer the digital controls run off the bottom of the screen However you can undock those controls click on the menu item View gt Dock Digital I O Controls When deselected the digital T O controls are freed in their own window and can be moved somewhere convenient or minimized 9 1 8 Bit Digital Output Clicking on an individual bit causes that bit to illuminate on the GUI and the corresponding output line to go into the high HIGH state Clicking again causes the bit to extinguish and the corresponding output line to go LOW The available current to a USB device is 500mA maximum and this current must operate the oscilloscope and signal generator as well as the digital circuitry Consequently the digital drive current is very l
52. elect the appearance of the graticule grid in the display area Auto Measure Follow the menu heirarchy to select auto measurement of average am plitude and or frequency on Channel A or B Notice that the readout text can be dragged to different positions on the screen This is useful when setting up a screen display for capture in a document 6 Additional Features Section 5 described the basic controls of the oscilloscope In this section we describe additional controls for more specialized measurements 6 1 Screen Capture It is extremely useful to be able to capture oscilloscope screen shots One or more screen shots may be used to document a particular measurement situation as a record of the measurement or to capture the result for a larger document The oscilloscope main window or any of its subsidiary windows measurements panel histogram spectrum display can be captured to a JPEG image file Selecting the menu item Tools gt Screen Capture jpg brings up a small dialog Clicking on one of the selections then brings up the standard File Save menu and the file may be named and saved where required The screen shot can only be saved in JPEG format If it is needed in another format load it into a drawing or image processing program and save it in that format Under the Windows operating system you can use Paint for this purpose Under Linux the program Imagemagick can convert to a variety of image formats 6 2 Export t
53. erial port 4 Set the permissions for the USB Serial port The default situation is that root is the owner of the USB serial port tt yUSBO and operation is restricted to root For an ordinary user to access the port the permissions must be changed First we will show how to do this manually in section 12 2 1 However Linux is usually set up so that the permissions revert back to root mode every time the USB is plugged and unplugged and every time the system is rebooted Therefore we need to modify the system so that this is done automatically ie so that the port permissions are set to user mode by default This is shown in section 12 2 2 below 12 2 1 Manually Changing Device Port Permissions Change to the dev directory phiscock linux gt cd dev Check the permissions on the tt yUSB ports 43 phiscock linux dev gt ls 1 ttyUSBx crw rw 1 root uucp 188 0 2005 11 07 18 25 ttyUSBO crw rw 1 root uucp 188 1 2004 10 02 01 38 ttyUSB1 lt others deleted gt In this case the owner root has read write access The group that root belongs to uucp also has read write access Others that s you have no access at all To open up the port to user access enter root mode using the su command phiscock linux dev gt su The system asks for the root password Enter it Now you can change the permissions mode for the ports In this case we ll use the chmod command to add read and write permission for others For exa
54. erial Converter Drivers B GSview 4 7 Size Set Program 19 Intel R Graphics Media Accelerator Driver for Mobile ES ae F iTunes Sie 33 48MB amp J25E Runtime Environment 5 0 Update 1 Size 143 00MB Ly J2SE Runtime Environment 5 0 Update 5 Size 144 00MB R Launch Manager Y1 0 8 5 Size 1 70MB 5 Macromedia Shockwave Player he Microstar Laboratories Filter Generation Figure 23 Add or Remove Programs System Restore Automatic Updates Remote General Computer Name Hardware Advanced Device Manager on your computer Use the Device Manager to change the SY The Device Manager lists all the hardware devices installed properties of any device Drivers Driver Signing lets you make sure that installed drivers are compatible with Windows Windows Update lets you set up how Windows connects to Windows Update for drivers Driver Signing Windows Update Hardware Profiles Hardware profiles provide a way for you to set up and store E ations Hardware Profiles different hardware configur __ Cancel Apply Figure 24 System Properties 4 Click on the tabPort Settings You should not need to change any of these settings 5 Find and click on the Advanced button to obtain the Advanced Serial Port Properties screen of figure 27 6 In figure 27 the COM Port selection is highlighted Click on the arrow to show a selection of COM ports Use the up and down arrow to scroll throug
55. ertical channels This calibration is performed when units are ERMEE ox tested so in general it should not be necessary to do this ee calibration repeatedly The calibration panel is started from the Tools menu and appears as in figure 4 To operate the calibration procedure Channel A Channel B 20 18 Channel A Channel B 50mV 500mV Range 50mV 500mV Range Place the scope in Auto trigger mode Remove any inputs from scope channel A 25 21 Set the Channel A vertical gain to 1 V div Save Calibration Values to Device Disable Channel B Drag the Channel A trace up and down You will Figure 4 Scope Offset Calibration Panel see a dashed line separately from the Channel A trace for a brief instant before the scope triggers This red dashed line is the zero reference Move the zero reference for channel A vertically to the centre of the screen Adjust the offset adjustment slider Channel A 1V 5V Range control until the channel A trace is over top of the red dashed line Set the Channel A vertical gain to 500m V div Adjust the slider Channel A 50mV 500mV Range control until the channel A trace is over top of the red dashed line That completes the offset adjustment for Channel A Repeat the procedure for Channel B Clickon Save Calibration Values to Device This transfers the offset values to the EEPROM memory in the hardware Close the Offset Calibration display window 15 6 4 Scope Amplitude
56. esents a post trigger count of 276 so 748 samples will be captured before the trigger event and 276 samples will be captured after This command can be used to examine events before and after the trigger of a given capture S R REG_VALUE Scope Update the control register REG_VALUE Bits Function 3 0 Sample rate select The sample rate is determined by the following formula Sample rate 20MS s 2 Where N is the 4 bit number 0 15 made up of bits 3 down to 0 in the scope control register 4 Trigger Source 0 Channel A 1 Channel B 5 Trigger Polarity 0 Rising 1 Falling 6 Internal or External Trigger 0 Channel A or B as defined by bit 4 1 External S D DEBUG_CODE Scope Debug hardware command Debug Code Function 0 Set RESET 0 1 Set RESET 1 2 Set REQ 0 3 Set REQ 1 4 Set MAN_TRIG 0 5 Set MAN_TRIG 1 All these bits are active high ie RESET 1 causes a hardware reset REQ forces a capture request MAN_TRIG forces a manual trigger The manual trigger will only fire if the scope control register is set to external trigger Command The scope will reply with a message when the capture is complete The message is three bytes long The first byte is the A character indicating that the scope is returning the address where the capture ended in the scope circular sample buffer The second and third bytes are in binary format and form a 10 bit number representing the ending address The trigge
57. f the input signals A measure of these extra signals is a measure of the intermodulation distortion e The existence of certain frequencies in a signal may give some clues as to its source For example if a signal contains the power line frequency eg 60Hz in North America 50Hz for the UK then it is probably picking up interference from the AC power line e Power systems frequently manipulate waveforms by chopping them or combining them with other signals Spectrum analysis allows one to measure the harmonic content of a signal which may be specified as a requirement e The analysis of a mechanical system for resonances can be done by driving the system with a wide band excitation signal an impulse hammer blow or random noise from a shaker Microphones or accelerometers convert the mechanical vibration of the system to an electrical signal The spectrum analysis of this signal indicates the mechanical resonances in the structure e The extraction of signals from noise may require some knowledge of the spectrum of the signal and the noise e It is useful to see the spectrum diagram for modulation and other signal manipulations Further information on spectrum analysis is in the paper Introduction to Digital Spectrum Analysis which is on the Syscomp web site 23 6 8 Data Record Data Logging Oscilloscope waveform data recording is started with the Data Recorder control panel found as menu item Tools gt Data Recorder figure 1
58. fying and Running Source Code Contents 1 Overview 2 1 1 Oscilloscopes lt lt be tebe ee heed he eee nae RR en bad a Gb baw eo 2 1 2 Waveform Generator visir a eS R R wR a eH ae 3 1 3 Digital Input Output S cor ee 3 Le General 2 pes Se Keb A eS SG Aad PUG A SEES aes 3 1 5 software Updates and Helps s s i esc ee ee Mee ea be Se bee ede eee See es 3 2 Applications 4 3 Features and Specifications 5 4 Installation 6 4 1 Windows Installation cocoes 2453 eddog Reed ERE ER EES ee we eS 6 441 1 First Time Operation iy es et E eh ee BESS Ged ee Be OD ERE SS EE EH 8 4 1 2 Setting the COMPort Manually 2 2 2 20 0 0 02000 2 00020000000 8 4 2 Macintosh Install lt s sasae A eee nb ete betwee eee ba ete pbb ee ee 9 4 2 1 Checking the Host Machine e 9 4 2 2 GateKeeper oo ecis ra a a se Se ale 9 4 2 3 Installing Software from the CD o e 9 4 2 4 Installing Dover 22546654 e reses EE a Sew a es 10 4 3 Linux Installation lt lt orina owed ee RRR Gee et eedesbave He 10 4 3 1 Hardware Installation 2 2 lt 6 amp 6 644 24 5 oe Bae Pe eee oe Be ba eee ee 11 10 6 Observation of AC Line Voltages 11 Overview of USB Operation 4 3 2 Optional Running the GUI from Source ee 5 Oscilloscope Basic Controls 5 1 Amplitude ssar ra sr 28 Pad R TR A A ee ee ee ee 5 2 Tim base 453 4 oe kd ard e a e I oe o a RY A SG ees Sees 07 5 3 TMPSCMNE 2 eke eee ek E Eee ES eR ee
59. h all the COM ports If you wish to force the hardware to use a different COM port you may select that port number here 38 g Device Manager File Action view Help e m Eea Rl alza PUMA E 44 Batteries Computer Sep Disk drives q Display adapters 2 DYD CD ROM drives 29 Human Interface Devices 8 2 IDE ATA ATAPI controllers Keyboards Mice and other pointing devices BL Modems fh Y Monitors 88 Network adapters i 5 Broadcom 802 11g Network Adapter i 88 Realtek RTL8139 810x Family Fast Ethernet NIC 6 a PCMCIA adapters i Generic CardBus Controller to fl Intel PCIC compatible PCMCIA controller A T Ports COM amp LPT Serial Port COM4 E P Sie sent 0 9 Sound video and aame controllers zl Figure 25 System Properties Hardware Device Manager 12 1 5 Checking the Connection with Hyperterminal We can do a very simple test to ensure that the hardware is operating 1 As described above use Windows Device Manager to determine which COM port the hardware was as signed to 2 Open up Hyperterminal Programs gt Accessories gt Hyperterminal and create a new connec tion to the CircuitGear COM port 3 Set up the connection with the following settings Baud rate 230400bps Data bits 8 Stop bits 1 Parity None Flow control Hardware RTS CTS 4 Under the Hyperterminal Menu navigate to File gt Properties gt Settings gt ASCII Setup
60. harmonic is at 90kHz The spectrum display readout puts the 9th harmonic at 90234 Hz which is only 7The FFT routine requires that the number of points be a power of 2 21 approximately correct Frequency Scale Bin Spacing It is sometimes useful to be able to determine the resolution of the frequency axis Each frequency bin has a width Af 1 T Hz where T is the length of the data record in seconds If there are N points in the data record then N 2 points are displayed as positive frequency The other N 2 points are redundant Example Determine the frequency resolution bin spacing for the case of the display of figure 10 Solution The sample rate is 200kS sec The sample interval AT is the reciprocal of this 1 200 x 103 5 pSec AT The number of points N in the data record is 512 points so the total length of the data record is T NAT 2 56 mSec The resolution Af is the reciprocal of the record length Ar 2 T 390 625 Hz For example the 7th harmonic should appear at f7 70kHz The spectrum display actually puts it at 70313 Hz which is bin 180 Fz 180 x 390 625 70313 Hz The maximum frequency fmax on the display occurs at bin 256 100 kHz Spectrum Display Cursor Control For fine control over the spectrum frequency readout the left and right cursor buttons on the keyboard move the spectrum display cursor one pixel to the left or right 22 Windows Window or weighting functions
61. her Syscomp instruments in this series is released in plain text format under the GPL Gnu Public Lincense Consequently it is legal to modify the program in whatever way you may find useful We also encourage you to share your work with others The software is written in Vanilla Tcl Tk that is in the Tcl Tk language without any third party packages or linked libraries This makes it extremely simple to modify The program itself is in text form The code does not need to be compliled or linked it is executed directly from the text form by the wish interpreter Although the scope program is fairly complicated it is possible to create a powerful Tcl Tk program with a sophisticated user interface with only a few lines of Tcl Tk code To set up for development ensure that the wish interpreter is installed on your computer Under Linux it is probably already there Under Windows you need to download and install a file from the ActiveState website http www activestate com Products languages plex tn 1 Download the appropriate exe file for your operating system Run the program to install Tcl Tk Make a copy of the original code of course and put it in a safe place Then using a text editor read and modify the existing code When you want to test the code run the wish interpreter Execute the source command with the name of your file and the program will execute Repeat this cycle until you have the desired result We d like to hear about
62. i i u Ground L Green i Ground Strap p Figure 19 Floating Power Supply If the ground terminal of the oscilloscope is connected to the ground terminal of the power supply then the circuit is in no danger and will work properly However if the ground terminal of the oscilloscope is inadver tently connected to the positive terminal of the power supply then the power supply will be connected to a short circuit The power supply short circuit will drive current around the ground connections of the power supply and oscilloscope Since lab power supplies are usually current limited to less than an ampere of current the equipment will likely survive However the circuit will not function properly because the power supply is in a short circuited condition To avoid this situation do not connect the positive or negative terminal of the lab power supply to the ground terminal Leave the supply floating 10 3 Battery and AC Adaptor Power Supplies If batteries are used to power the circuit under test the problematic situation of section 10 2 is not likely to occur because batteries do not normally have a ground connection to the AC line An AC Adaptor is essentially a small transformer coupled DC power supply These are usually supplied with a two prong line cord so there is no ground connection to the AC power line ground The supply is floating so the problem of section 10 2 cannot occur 10 4 Russian Roulette and AC Line Voltage
63. igure 6 Choose the resistor to be larger than the maximum impedance of that component Then in effect the device is driven by a constant current and the voltage across the device is proportional to its impedance The display is the amplitude and phase response of a small 1 1 audio transformer The primary was driven by the generator and connected to Channel A The secondary was connected to Channel B Notice that the amplitude response rolls off below 20Hz and exhibits very substantial peaking around 300kHz This shows up as ringing in the square wave time domain response The transformer midband phase response because the transformer primary and secondary are deliberately wired out of phase The jump in the phase response from 180 to 180 is correct plus or minus 180 degrees is the same physical result e Two slide controls set the start and finish frequency e A third slider sets the frequency step The frequency step is the amount by which a frequency is to in crease to create each new measurement frequency Or put another way it s the ratio between two adjacent measurement frequencies The frequency step multiplies by a factor rather than adding a constant factor because the frequency scale is logarithmic The network analyser frequency labels can be viewed in fixed point or scientific notation This is selectable under the View menu e A fourth slider sets the signal amplitude 17 The Oscilloscope Display window shows th
64. imited a few milliamps per output Load devices such as high current LEDs or DC motors will require their own power supply 9 2 8 Bit Digital Input The GUI digital input indicators illuminate when the corresponding input level is a logic HIGH The logic levels may correspond to 3V HC logic or 5V HC logic Great care should be taken not to exceed 5 volts on any input Inputs are buffered but all devices are surface mount soldered so they are not trivial to replace 9 3 Interrupt The interrupt is a 3V or 5V HC compatable logic input A dropdown menu below the interrupt indicator button establishes the mode of operation one of Disabled Rising Edge Falling Edge High Level Low Level When the specified type of interrupt occurs the indicator illuminates Left click on the indicator to clear the interrupt 9 4 PWM Pulse Width Modulated Waveform The PWM output is a 5 volt pulse The duty cycle is continuously adjustable with the slider over a range of 0 to 100 The output frequency is set from the drop down menu below the slider over a range of 72kHz to 35Hz Again the output drive current should be limited to a few milliamperes of current 29 9 5 External Trigger When the Trigger Mode control on the GUl is set to External a positive going transition on this pin causes the scope to trigger To test external trigger 1 Set the trigger mode to auto 2 Connect the output of the generator to channel A of the sco
65. ing the Custom waveform pops up a file i N im H i i U N IN i i selection box so you can select any waveform A waveform data file can be constructed manu ally using a programming language eg Visual Basic or from a spreadsheet eg Open Office calc The GUI based program Wavemaker available at http www syscompdesign com download htm can be used to draw a waveform and convert that drawing into a suitable data file There is a 1 to 2 second download delay after selecting a waveform before the generator begins producing the waveform During that time other waveform selection buttons are locked out to prevent button mashing Triggered Figure 15 Noise Waveform 8 6 Noise CircuitGear can generate a random noise signal figure 15 which is useful in transfer function measurents by correlation and acoustical testing The output spectrum is white that is equal energy per hertz bandwidth The noise is generated by a 32 bit shift register configured to give a pseudo random bit sequence and clocked at 100MHz See http en wikipedia org wiki Linear_feedback_shift_register Ev ery 8 shift pulses an 8 bit sample is extracted and converted to analog form Consequently the noise rate is 12 5Msamples second The shift register sequence length is 2 1 shifts before repeating which gives a repeti tion period of 42 seconds The amplitude spectrum is actually a sin x x function but for practical purposes the spectrum is fla
66. is View Tode Dindan Help Start Frequency Lo ia PA dl End Hequency TUULUUU U Frequency Step 111 Se 2 nil THT rit Hill Maximum Waveform Amplitude 77 O 1020 30 40 50 60 70 80 90100 START STAP Curent Frequency 360 8 kHz Channel A Preamp Ravma Channel B Preamp 25 Mex Waveform Amplitude 221 50 Analizer Status Idle Oscilloscope Display VWAWA Figure 7 Vector Network Analyser of changing component values For example if the resistor or capacitor value in an RC lowpass filter is changed one can immediately determine the effect on frequency and phase response The CGR 101 has two principal modes as an oscilloscope and signal generator with digital input output and as a network analyser To change between them select Hardware gt Network Analyser Mode or Hardware gt Circuit Gear Mode Figure 7 shows a screen shot of a VNA plot of a single pole RC lowpass filter Figure 6 shows how the test circuit must be wired Notice that there is no internal connection between the generator output and the channel A input To measure the impedance of some other two terminal device such as an inductor or loudspeaker connect it in place of the capacitor in f
67. ket cable can jumper two pins on the rear panel connector This is a good way to test the digital IO signals The socket socket cables are available from Digikey EZ Hook part 9110 12 S but they are hideously ex pensive about 4 each I prefer to get those cables from Creatron Electronics in Toronto because they are much less expensive a package of ten is about 4 50 31 Creatron has the cables in pin pin pin socket and socket socket configuration 3 inch 6 inch and 12 inch lengths Creatron don t give a part number or show these parts on their website but they do use Paypal You can phone or email them to select a part and arrange shipping Creatron 255 College Street Toronto Ontario Canada MST 1R5 Tel 416 977 9258 Web http www creatroninc com Email support creatroninc com 10 Safe Measurement Technique These notes are included for the benefit of those who are new to using an oscilloscope The information is not unique to this oscilloscope but applies to most oscilloscope measurement instruments Rather than simply state rules and prohibitions we explain why certain procedures are dangerous and why some techniques should be avoided This information is provided for guidance in using the oscilloscope and is not intended to replace proper training in working around high voltage circuits In general this oscilloscope may be used safely to observe signals in low voltage circuits where the power supply is floating from
68. may be derived from the Channel A waveform or the Channel B wave form Generally it is easier to obtain a stable trigger signal from the simpler of the two waveforms Manual Trigger Actuating this button generates a trigger signal This is sometimes useful to cause the scope to capture one waveform Trigger Level Readout This display shows the amplitude of the trigger level setting Display Lag For low frequency waveforms displayed at slow timebase settings there is a noticeable lag between display updates This occurs because each display is shipped back to the host as a complete waveform and it takes time for the 1k memory to fill with data Display Refer to figure 3 on page 12 Vertical Position A waveform may be moved in vertical position At startup the A and B cursors which are the zero reference for the channel are placed at centre screen Using the mouse drag the letter A or B at the right edge of the display area up or down to change the vertical position of the corresponding waveform 13 e Time Cursors It is possible to enable and disable various time and amplitude cursors Right click in the display area A menu appears Toggle Time Cursors Left Click to enable and disable vertical cursor lines that mark the time between two locations on screen Toggle Channel A or B Cursors Left Click to enable and disable horizontal cursor lines that mark the amplitude between two locations on screen Grid Left Click to s
69. minimum Then the adjustment range of the gen erator is 100Hz giving effective fine grain control of frequency 8 3 Sweep Mode The control characteristic of the frequency slider can be set to Logarithmic or Linear The Logarithmic control increases the frequency in an exponential fashion as it is increased which is the most convenient characteristic is most situations In Logarithmic Mode the physical mid point of the scale corresponds to about 700Hz In Linear Mode the control characteristic is linear and the mid point of the control is 1 5MHz In effect this assigns most of the physical movement to high frequencies 8 4 Manual and Automatic Sweep The CircuitGear GUI provides frequency control of the generator with a manual frequency control Automatic sweep is provided with a separate program the VNA Vector Network Analyser aka Bode Plotter software which operates the generator to make a sweep and the oscilloscope to plot the response of some device or network 27 8 5 Waveform Selection There are six possible waveform selections Selection of a waveform except Noise causes that waveform data to be downloaded into the CircuitGear hardware Each waveform data file consists of 256 data points Each data point has a value between 0 and 255 The files for Sine Square Triangle and Ramp are supplied with the GUI software If you download the source code these files are named sine dat and so forth Wine iit All HN l Select
70. mple the first command below says change the mode of device ttyUSBO to add read permission for others The second command does the same for write permission linux dev chmod o r ttyUSBO linux dev chmod o w ttyUSBO Check the permissions again ls 1 ttyUSBx crw rw rw 1 root uucp 188 0 2005 11 07 18 25 ttyUSBO crw rw rw 1 root uucp 188 1 2004 10 02 01 38 ttyUSB1 That s it You should now be able to access those ports from user mode Exit from root to user mode Incidentally you may be able to change the permissions by logging in as root and then using the features of the KDE or Gnome desktop to change the permissions 12 2 2 Setting Default Port Permissions to User Mode Suse 9 2 This change will ensure that the serial usb ports are always created with user mode access The default permissions for user devices are contained the file etc udev permissions d 50 udev permissions We have to modify the entry for the tt yUSBx ports so that the default is user mode 1 Change to the directory etc udev permissions d and check that the file 50 udev permissions ex ists 2 If the file exists enter root mode and copy the existing file so you have a copy of the original cp 50 udev permissions 50 udev permissions orig 3 Now open the file 50 udev permissions with your favourite editor Find the entry that says ttyUSBx root uucp 660 Change that to read ttyUSBx root uucp 666 Save the file Now every time a t
71. mples each channel Export to Postscript Selectable screen capture Cursor Readouts Spectrum Analysis FFT Real Time Histogram X Y Plot Export to Postscript Selectable screen capture Data record to CSV file Save Load Settings Cursor Readouts Auto Measurements Vertical Calibration Labview Drivers 0 1Hz to 2MHz 3V Hardware 8 bits at all amplitude settings 150 ohms Sine Square Triangle Ramp Arbitrary Noise 8 bit resolution vertical 256 time points Constructed with Wavemaker software Pseudo random 8 bit analog noise sample rate 12 5Mz sequence length 21 seconds GUI Graphical User Interface controlled 5 volt HEMOS GUI indicators 5 or 3 volt HCMOS Variable duty cycle at constant frequency 35Hz to 72kHz in steps of x2 Interrupt Selectable level and slope illuminates Interrupt indicator 4 Other Indicators Power LED Green Activity LED Red Interface USB 2 0 Emulated serial port Physical Dimensions 3 x 5 GUI Source Code Tcl Tk language Open source OSI Compliant Windows Linux Mac operating systems Current Consumption Scope Only 230mA Function Generator Amplitude 100 Open Circuit load 240mA Function Generator Amplitude 100 Output Shorted 260mA Installation The installation should work correctly under modern versions of Windows Linux and Macintosh operating sys tems 4 1 Windows Installation The installation procedure unpacks and installs the
72. n entry window appears Enter the amount by which the frequency increases for each measurement This value must be greater than the minimum fre quency step for the waveform generator which is 0 1Hz e Both Logarithmic and Linear sweep will work but the Linear Sweep setting allows more precise control of the display range Select Linear Sweep to precisely set the display frequency span to the previously entered Start and End frequencies e Select the maximum amplitude range e Press Start and the analysis will proceed If the sweep range is substantially outside the passband of the filter the VNA may complain about insufficient signal In that case change the sweep range to start and end on the skirts of the filter Phase Display When the phase is close to the top or the bottom of the display small phase changes can cause it to jitter in an annoying fashion from one limit to the other For a signal that changes over a wide range of phase this cannot be entirely prevented However it can be reduced by adjusting the vertical scale of the phase display By default the phase display ranges from 180 to 180 with 0 in the centre To change this place the cursor in the phase plotting area and right click A menu appears allowing the selection of a different phase display arrangement 360 to 0 for example VNA Theory More information on the theory of the vector network analyser is in the Syscomp Application Note A Software
73. ne cycle This is required to define the limits of integration in the RMS calculation For multiple measurements on a reasonably clean waveform the Auto Measurements can be a real time saver However it is best to verify that the measurement is reliable before relying on it extensively 25 7 Syscomp USB Digital Storage Oscilloscope PSO 181 7 File View Tools Hardware Help Syscomp Digital Storage Oscilloscope Vertical Controls Trigger Controls Channel A Measurements Trigger Slope r Measurements RR oe oe nR R Pus 2 Frequency 1000 000 Hz L q F h 7 R mi Trigger Source DetaT 1 000 ms H b i H H A A 3 Delta VA 1 000 V H A H 3 H h H H PA dE er 7 Manual T a o A E Auto Measurements Pl E 00 lomy Frequency ane 15 i Timebase Controls Period 40me RT jas Average 2900 AMV ML Minimum as aw Hide Measurements Pesk Pesk Maa Figure 13 Measurements Screen 7 Aliasing The oscilloscope is a sampled data system It works by taking a series of samples of the input waveform and displaying them However when the signal contains high frequency components compared to the sampling rate the display may be incorrect In theory at least two samples per cycle of the highest frequency present in the waveform are required to reconstruct the waveform correctly Some sampled data systems have a constant sampling rate For example audio i
74. ng window shows a list of the unavailable COM ports and the one that was found Click on Back The Port Settings control panel shows which port has been selected Click on Save and Exit This causes a small text file scopeport cfg to be written to the directory where the scope program was launched This file contains the connection port number At this point the Connected indicator at the top of the GUI screen show show a green colour The unit is operational From now on whenever you double click the program icon the program should start and automatically con nect 4 1 2 Setting the COM Port Manually 1 Using a USB cable plug the oscilloscope into a computer USB port If you have more than one USB port you can chose any port The green LED on the hardware unit should illuminate and the computer will make its USB boing noise Go to Start gt Settings gt Control Panel gt System gt Hardware gt Device Manager On the Device Manager panel click on Ports COM and LPT You should see an entry like USB Serial Port COM 5 This is the COM port that the operating system has assigned to the oscillo scope for this session Make note of the port in this example COM 5 On the oscilloscope GUI open Hardware gt Connect Select the COM port that you found previously In our example that would be COM 5 Click on Save and Exit The oscilloscope GUI status message at the top of the screen should sho
75. ng to 1 A D count The conversion from sampleVoltage to screen coordinates is application dependent If you re interested in how we translate from voltage to screen coordinates in the CircuitGear GUI look at the scope plotScopeData procedure in the scope tc1 source file Scope Query scope state machine where the scope state s is one of the following State 1 Idle State 2 Initializing capture State 3 Wait for trigger signal to reset State 4 Armed waiting for capture State 5 Capturing State 6 Done SP AlaIBIp A Set preamp A to 1 2 5V range 25V max Set preamp A to 500mV 200mV 100mV SOmV range 2 5V max Set preamp B to 1 2 5V range Set preamp B to 500mV 200mV 100mV 50mV range Command SO Scope Read offset calibration Returns the offset values stored in eeprom in the form OAaBb where A a B b are 8 bit signed numbers corresponding to the offset for each channel and range setting The read offset command returns all four offset values Channel A High Offset Channel B High Offset Channel A Low Offset and Channel B Low Offset These values values are fixed and do not change so you should only have to read them once The software should know the setting of the preamp and apply the corresponding offset value Command SFAaBb Scope Store offset calibration into eeprom Allows the user to store 4 8 bit numbers into the device eeprom for offset calibration Refer to the GUI for an example Command DON Digital
76. o Postscript Section 6 1 on page 14 described the oscilloscope the Screen Capture features These features support the capture of any oscilloscope screen window to a JPEG image file It is also possible to capture the waveform display area of the main oscilloscope display as a postscript file Select the menu item Tools gt Export to Postscript PS File brings up the standard File Save menu and the file may be named and saved where required What are the relative advantages of JPEG screen capture vs exporting the display area to a Postscript file e Screen Capture grabs everything inside the selected window This may be useful if you need to docu ment the control settings Furthermore Screen Capture can capture any of the scope windows Export to Postscript grabs only the waveform display area on the main oscilloscope screen e Certain writing tools may require image format to be postscript It is entirely possible to convert a JPEG image to Postscript but the file size is quite large If you need the waveform in Postscript format and file size is an issue then you might be better off capturing just the waveform area in Postscript format e Both the JPEG capture and Postscript capture are in colour 5 Acknowledgement Special thanks to John Foster who helped develop the screen capture code 14 6 3 Scope Offset Calibration The CircuitGear CGR 101 includes provision for mea suring and substracting any DC offset into the v
77. o waveforms is useful in taking a differential voltage measurement across some component when neither terminal of the component is grounded The input voltages must be within the amplitude capability of their respective channels It is a relatively simple matter to add other functions to the math toolbox see the source code file math tcl 6 10 Measurements Screen The Measurements Screen shows cursor and automatic measurements of the most common features of a wave form amplitude and time As shown in figure 13 the Measurements Screen is in a separate window This window defaults to being displayed that is it is displayed when the program is first started The Measurements Screen may be hidden by clicking on the X in the upper right corner of the measurements window It may be displayed by clicking on the menu item View gt Auto Measurements The Measurements Screen shows the Auto Measurement s in which the software automatically measures waveform parameters The Frequency and Period readouts are based on the zero crossings of the waveform Consequently the waveform must be periodic and the main display must show at least one complete cycle of the waveform for the frequency and period values to be meaningful As well the frequency and period measurement can be fooled if the waveform includes noise that causes multiple spurious zero crossings The RMS measurement requires that the time cursors be visible and set to the beginning and end of o
78. oftware does not operate correctly here are some things to check They are subsequently explained in detail e The operating system is too old and does not contain the necessary drivers for the usb serial ports e The operating system for some reason is not recognizing the usb device and assigning it to a usb serial port This can occur if the usb device has root ownership and permissions The permissions must be changed to allow a user mode program to access the usb port e The operating system is assigning the hardware to some usb serial port but the Tcl Tk program is not automatically selecting that particular port You ll need to select the usb serial port manually using the controls in the Tcl Tk program e The wish program which is the interpreter for all Tcl Tk programs is not being found by the operating system Locate it and change your path so that it is found e The device is being recognized and connects properly but does not respond properly to certain controls Use the instructions in section 16 2 to send commands to the hardware to determine how it is functioning 1 Check the kernel version The drivers for the FTDI USB Serial interface are a standard part of the Linux kernel from version 2 4 onward To check that you have a sufficiently modern kernel run the dmesg command piped to the more command 42 phiscock panther dmesg more Examine the first few lines which should be something like this Linux version 2 6 8
79. ons and mak ponts Add change and manage fonts on your computer Game Controllers Add remove and configure game controller hardware such as joysticks an inter oma Driver For Mobile Control the graphics hardware features of your system Dinternet Options Configure your Internet display and connection settings Seva Java TM Control Panel aKeyboard Customize your keyboard settings such as the cursor blink rate and the ch TY Mouse Customize your mouse settings such as the button configuration double cl WE Network Connections Connects to other computers networks and the Internet T Network Setup Wizard Launch the Network Setup Wizard Phone and Modem Options Configure your telephone dialing rules and modem settings W Portable Media Devices View the portable media devices connected to your computer Power Options Configure energy saving settings for your computer printers and Faxes Shows installed printers and fax printers and helps you add new ones QuickTime Configures QuickTime software and hardware components Regional and Language Options Customize settings for the display of languages numbers times and dates Tel S scanners and Cameras Add remove and configure scanners and cameras scheduled Tasks Schedule computer tasks to run automatically security Center View your current security status and access important settings sound effect Manager AC97 Audio Control Panel 9 Sounds and Audio Devices Change the so
80. ope GUL s R d R rr IAE AA A Ee e 4 scope Offset Calibration Panel xo cos a dt OES A SO ed BS Se 5 Scope Vertical Calibration Panel 2 2 E E ee ee 6 Network Analyser Wiring R R E R R E ece RR RR R R R RR RR 7 Vector NetWork Analyser cs E C vn RTE a a ee ae ae E 8 XY Display Mode i020 X ee 4 ee eee eS CE ey a Ra ee be ae 9 Diode Voltage Current Characteristic s 2 ee 111 51 51 52 52 53 54 58 58 58 59 10 11 12 13 14 15 16 18 19 20 21 22 23 24 25 26 27 28 29 30 31 Square Wave Spectrum vidrio 21 Data Recorder Panel lt a E 445 64 844 Fb seh SUD e bbe ee Pea eee ne 24 Waveform Math Tool 3 5 va SA we aged ae SB eR Re OAs wee Poko a ee eee es 25 Measurements Sereen so o ap cea R A a a eS 26 Generator Controls ados A e A EG Ee 27 Noise Waveform Lepra ra AAA 28 Digital Controls veais esc e AE deed ob 29 CircuitGear Rear Panel Connector Pinout e e 31 Floating Power Supply s s r acs 5654 46448 5 a a ee eS 32 Floating Power Supply ss Se Rae R Te ok ee a WOR Be BH ko as 33 AC Line Voltage pss saraa hbee ee bbe Bese hee A 34 My Computet lt i bea eae Soa ease baw beeanea Dae eee Beha ae beau es 37 Control Panel s s e See ap OSA ee e ee ae a d 37 Add or Remove Programs cortas ia i EG ee we Ge a 38 System Properties lt S gt nic 62h be e ee See ae eR R i 38 System Properties Hardware Device Manager 000000000 39 Seral Port Properties 5 se oso d R BAe Bae ee ee
81. orm Generator The waveform generator controls are shown in figure 14 The Amplitude control is calibrated from 0 to 100 8 1 Setting Frequency The frequency control adjusts frequency between the limits shown in the two buttons at the top and bottom of the frequency slider In the default these limits are 0 1Hz to 3MHz The frequency resolution is 0 1Hz The accuracy is based on a crystal clock A readout shows the current frequency to a resolution and accuracy of 0 1Hz You can set the frequency by moving the slider Al ternatively left click on the frequency display and enter a frequency value in the pop up dialog 8 2 Setting Sweep Limits To change one of these slider limits left click on it An entry widget appears prompting for a new maximum or minimum frequency Enter a new value and left click on OK or hit lt carriage return gt The new value appears above or below the frequency slider For example if you are sweeping an audio device you can set the maximum and minimum frequencies to 20 000 and 20Hz Then the full scale movement of the slider applies to that range As another example if you are investigating the fre quency response of a 3kHz narrow band active filter you Waveform Generator 3000000 Sine Square Triangle Sawtooth Custom Noise Sweep Mode Logarithmic C Linear Figure 14 Generator Controls could set the frequency range to 3050Hz maximum and 2950Hz
82. ort assignment 1t s best to choose a COM port number 4 or larger Lower numbers may conflict with a USB keyboard or mouse Suppose we decide to move to COMS The scrollbox says COM5 in use Select it anyway Click OK A warning pops up that the COM port is in use and asks if you want to continue Click on Yes Back out through the menues until you have closed the Device Manager panel Re open it and examine the Ports COM amp LPT This time it should read COM5 Back out to a clean desktop and restart the instrument program This time it should connect properly If you are connecting multiple instruments you may need to do this for each instrument However having once done the assignment for a given instrument the operating system associates that instrument with the chosen COM port and connection should be automatic 12 1 2 Checking the Installed Files This section details how to determine that the files are installed correctly 1 2 3 Double click on My Computer to obtain a screen like figure 21 Double click on Control Panel obtaining a screen like figure 22 Double click on Add or Remove Programs obtaining a screen like figure 23 Figure 23 lists the FTDI drivers so they are installed Similarily the Tcl Tk program for the unit should be shown on the same list under Syscomp 12 1 3 Obtaining Details of the USB Serial Port 1 2 On the Add or Remove Programs list of figure 23 find the entry System Double
83. ous because metallic connections on the computer such as the shell around a connector are connected to the ground line A connection to the AC line puts those metallic points at line potential presenting a serious shock hazard to the user and possible short circuit if attached equipment is grounded The AC ground connection the third prong on a plug is there specifically to prevent the chassis of the equipment from assuming a potential that is above ground and therefore dangerous to a human operator Re moving that ground connection removes any grounding protection This is a serious violation of health and safety regulations Similarily a battery powered laptop computer when disconnected from its line operated charger is not con nected to the ground line of the AC power system so it is less likely to cause the kind of short circuit described in the previous section However it is extremely dangerous to rely on this The laptop may itself become live at the AC line potential which makes it hazardous to the operator and any attached equipment such as a line operated video monitor 34 10 6 Observation of AC Line Voltages If you must observe line voltage here are the rules e The oscilloscope must be able to cope with the peak value of the input AC voltage The Syscomp DS 101 is certified to reliably accept up to 50 volts on its input terminal A times ten oscilloscope probe increases this by a factor of ten It is absolutely e
84. pe and adjust the generator amplitude so the scope shows a sine wave 3 On the rear panel use a jumper cable to connectthe Ext Trig pin to the Digital output 0 pin 4 Under Trigger Mode select External 5 From the GUI use the mouse to click on Digital Output 0 6 On the OV to 5V transition on digital output 0 the scope should briefly display triggered and a new sample of the waveform should display On the 5V to OV transition triggering will not occur Edge polarity is not selectable on external triggering the trigger edge is always positive going The trigger input is protected against overvoltages but we do not recommend relying on that We recommend keeping the trigger signal between 0 and 5volts 9 6 Rear Panel Connector The rear panel connector provides access to the following signals e Digital outputs O through 7 Digital inputs O through 7 Interrupt input PWM Pulse Width Modulated output e External trigger input Ground The pinout is shown on the case label of the instrument and in figure 17 below These functions are described in section 9 above 9 7 Rear Panel Connector Mating Plug One suitable rear panel connector mating plug is as follows MODE part 35 0202 0 20 position 2 row 0 1 2 54mm contact spacing Mates with 20 way 0 050 spacing flat cable Polarizing key Centre bump Strain Relief Active Tech price 0 38 Available from MODE Electronics http www mode ele
85. r point can be derived by subtracting the post trigger sample count Command Scope Read scope data buffer The scope will return the entire scope memory preceded by the D character The data is in binary format with the following organization AlalB1b2A2a2B2b2 Where Al is the upper byte and al is the lower byte of a 10 bit sample For example the value of the first data point is 256 A1 al No need to mask or shift There is no termination character at the end of the buffer The user should expect to receive 4097 bytes 4096 bytes for samples plus one byte for the D character at the beginning of the transfer The first sample comes from sample 0 in the ring buffer From the information in the S G command the software now knows the sample that 1s the trigger point so the software can reconstruct the timing of each sample on the display The waveform data is encoded as 16 bit integers which range from 0000 to 03FF hexadecimal The most positive value is 0000 The most negative value is 03FF Zero voltage is 01FF plus or minus the offset value The relationship between sample voltage and sample value is 55 sampleVoltage 511 sampleValue xadStepSize where sampleVoltage is the value of the sample in volts sampleValue is the integer value of the sample 0 1023 The adStepSize is 0 0521 for the high preamp setting and 0 00592 for the low preamp setting The scope getStepSize procedure will return the voltage step correspondi
86. rce code for the Oscilloscope GUI which is pro vided on the accompanying CDROM will be a useful source of ideas in controlling the scope There is no requirement that the controlling program be written in the Tcl language Any program that can issue ASCII strings to a serial port will be capable of controlling the scople hardware i e Mat lab Visual Basic 15 1 Using the Debug Console When you send a command to the scope it does not echo any confirmation back to the host terminal This is because you are doing with the terminal exactly what is done with a control program and responses from the scope would slow down the overall operation of the system Each command consists of an ascii string of characters such as T55 lt cr gt to set the trigger level to 55 where lt cr gt is a carriage return character If you are running under a Windows operating system in addition to the material in the user manual you can see commands being sent to the oscilloscope by selecting View gt Debug Console This brings up a terminal screen which lists commands as they are being sent to the scope hardware and some other debug information On Linux and Mac machines the operator starts the program from a terminal window executing a command like wish main tcl In that case the terminal window becomes the console This information scrolls past rather quickly when the scope is in auto trigger mode because it is repeatedly obtaining data from the har
87. reenfield College This applies to using the software in a lab environment where everyone using the Mac must be able to start the Syscomp software 1 2 Login as an administrator Open Safari and go to web site www syscompdesign com Select Downloads Select Mac OS X and download When the download is complete drag the Syscomp CircuitGear V1 15 icon into the Applications folder Open the applications folder check that it is there and drag an alias to the dock Put the Syscomp CD into the computer Open the folder Drivers Select Mac Select Intel Double click on FTDIUSBSerialDriver Double click on the Snow Leopard package Follow the instructions When the installation is complete eject the CD 50 5 Get the scope hardware and plug into an open USB slot 6 Click on the dock icon SYSCOMP Select OPEN from the popup When the Unable to Connect Examine Settings popup appears select YES When the PORT SETTINGS popup appears select the button dev cu usbserial Click on SAVE AND EXIT 7 If everything was done correctly a CONNECTED rectangle will change from red to green at the top of the open window the CircuitGear GUI If not repeat step 4 again 8 Now we need to set the permissions on the USB port so that all users can access the port To do this start the TERMINAL program In the terminal window type chmod 777 Applications Syscomp CircuitGear V1 15 app Contents MacOS port cfg and hit return 9
88. rm Set Amplitude The parameter AO is an 8 bit integer 0 255 representing the amplitude of the output waveform i e AO 128 output amplitude 50 Command W S ADDR DATA Waveform Program Sample The parameter ADDR is an 8 bit integer 0 255 representing the sample number The parameter DATA is an 8 bit integer 0 255 representing the waveform amplitude of the sample at address ADDR The data is stored in a waveform buffer in the generator handware Command WP Waveform Program waveform This command takes all of the data stored in the waveform buffer previously set up using the W S command and programs it into the FPGA changing the output waveform Description WW __ Select Waveform Output Select Noise Output These commands select between generator waveform output and noise output Scope Adjust trigger level T_HIGH and T_LOW represent a 10 bit number 0 1023 The trigger voltage is calculated as follows Trigger Value 511 Gain x Trigger Voltage 0 052421484375 Where Gain 1 for the 5V scale and Gain 10 for the 500mV scale Example Setting the trigger level to 1V on the 5V scale Trigger Value 511 1 1 0V 0 052421484375V 492 54 The command would bes T 1 236 S C C_HIGH C_LOW Scope Post trigger sample count The 8 bit numbers 0 255 make up a 10 bit number representing the number of samples that will be captured after a trigger event For example the command S C 1 20 repr
89. rning missing package such as the BWidget or Img package you ll need to download those as well Here s how e Ensure that you have the Tcl interpreter Wish installed on your computer e Start the Tcl interpreter by double clicking on the Wish icon or running the command wish85 or whatever is the current name That will create two windows the terminal window and a blank desktop window Inside the terminal window type the commands to download the missing packages eg teacup install with recommends B Widget teacup install with recommends Img The with recommends option Forces the handling of recommended dependencies as if they were required dependencies i e forces their installation e Now try rurning wish main tcl or double click on main tcl The CGR 101 software should start up correctly and the graphical user interface appear 14 Adjustments The oscilloscope has been adjusted before shipping so it should not need adjustment before use These instruc tions are provide for reference purposes 51 14 1 Input Compensation Capacitors The schematic of the input circuitry of the oscilloscope vertical preamplifier is shown in figure 31 2 5V Input Attenuator Figure 31 Scope Input Compensation Network The two channels are identical Stray capacitance at the output of the voltage divider has the potential for limiting the bandwidth To make the divider frequency independent the resistive divider R
90. rocessor to be used as the basis for a low cost digital analog converter The PWM signal is filtered to produce a variable analog control signal In this exercise students design the PWM filter and then measure the ripple using the CircuitGear oscilloscope They can also operate the PWM signal at various frequencies to illustrate the effect of frequency on ripple Oscilloscope Channels Sampling Frequencies Vertical Resolution Vertical Bandwidth Vertical Input Range Vertical Gain Settings Vertical Scale Vertical Preamp Ranges Horizontal Time Settings Horizontal Scale Input Impedance Triggering Trigger View Trigger Controls Memory Depth Software Initial Release Subsequent Release Waveform Generator Frequency Range Output Amplitude Amplitude Control Vertical Resolution Output Impedance Waveforms Arbitrary Waveform Noise Digital O Output Input Pulse waveform 8 bits 8 bits 3 Features and Specifications The features and performance specifications are as follows 2 independent channels sampled simultaneously 20 MSamples second maximum 10 bits per channel 1 1024 2 MHz 250mV to 25V full scale 7 settings 50mV div to 5V div in 1 2 5 sequence 10 major divisions 2 20 settings 100mSec div to 50nSec div in 1 2 5 sequence 10 major divisions 1M Ohm parallel 27pF Digital comparison with input signal Pre and Post trigger simultaneously viewable Source A B Manual level and slope select 1K Sa
91. s must meet certain requirements in order to generate trigger signals for waveform capture If these controls are not set properly it is possible that the scope will not capture waveforms and the display will appear to be frozen Alternatively the display may appear to jump between captures without a stable waveform display 12 5 4 Trigger Time The trigger time is marked by a vertical cursor with an X symbol at the top The trigger point may be dragged left or right to reveal more or less of the waveform preceeding or following the trigger point This ability to view the waveform preceeding the trigger point is one of the advantages of a digital oscilloscope Trigger Level The trigger level is marked by a horizontal cursor with a T symbol at the leftmost edge of the screen The trigger level may be dragged vertically to set the amplitude on a waveform that establishes the trigger point In order to cause triggering the trigger level cursor must be positioned within the amplitude of the triggering waveform As the trigger is dragged an accompanying readout displays the trigger amplitude in volts Trigger Mode Auto Normal Single In the Normal position the scope hardware must get a proper trigger signal in order to display a new waveform Without a trigger signal the display simply waits The Manual Trigger button can be used to force a trigger event that is display one capture In the Auto position if there is a trigger sign
92. s to User Mode Suse 10 3 12 2 4 Setting Default Port Permissions to User Mode FedoraCore6 12 2 5 Running the Program cocer 44 e448 be See cms rra te aa ne 12 2 6 Ubuntu Linux Install e 1227 GABE LDUX oy ose a eek ee A Bok doy BERS A ee we a ee 12 2 8 Running under 64 bit Sidux Debian based Linux o o a 12 2 9 Device Properties using usbview 2 2 2 000000 0000 0004 12 2 10 Terminal Connection under Linux lt lt ete semea inre me 0 000000 00004 123 Macintosh 45 5 2 b s 4 3 a 4 SS ewe OY ee ee oe ee es ee eS 13 Modifying and Running the Source Code 14 Adjustments 14 1 Input Compensation Capacitors ee 15 Oscilloscope Commands 15 1 Using the Debug Console 2 5 be ee ee ee ea eee bee ee 15 2 CircuitGear ASCII Command Set R R R R R R 00000000022 eee 16 Manual Operation 16 1 Ta Te s poea E 5444 04 DE E eed een eeeegan Su deeseeuay ud 16 2 LINUX oes es bw hee WARDS OE ee ee Shee ew ee det de 17 Modifying the Tcl Tk Software 18 Sources of Information 18 1 News Groups o aio Gee be eed dens deed Gee Seeds dave ee 18 25 WeDSIICS ea 4 Sg Se Wo A A ee ee OE ee ee Ee Be E t83 Paper as odd att Gandy ty By eae ees Gs Bae hy hs eh Gs BS Se IS Ay LEXIDOORS o 000 we Ge oe ee OE ee eae ewe SE Ee ee ee Owe ewe Hee wre Ee List of Figures 1 CircuitGear Graphical User Interface GUI a 2 Windows Installation Screens ee 3 Oscillosc
93. s typically sampled at 44 1k samples per second In that situation usual practice is to incorporate a low pass filter such that frequencies above 22 kHz are prevented from entering the system Most if not all digital oscilloscopes do not incorporate an anti aliasing filter The sample rate of a digital scope varies over a wide range of frequencies and so the cutoff frequency of the anti aliasing filter would have to do so as well Combined with the bandwidth requirement that is a difficult technical challenge Instead the oscilloscope relies on the operator to recognize when aliasing is occurring and increase the sample rate until the effect disappears A useful strategy in measuring an unknown waveform is to approach it from a high sampling rate aka time base setting and reduce the setting until a readable display appears It is also required of the operator to know approximately the frequency of the waveform that is being observed That is often the case A useful rule of thumb is this the display must contain about 10 samples per cycle of the waveform to reconstruct it For this oscilloscope the maximum sampling rate is 20MSamples second so it can usefully observe frequencies up to about 2MHz The analog bandwidth has been designed to be 2MHz to meet this requirement 8In practice the lowpass cutoff frequency is set to somewhat less than half the sampling frequency to allow for the finite rolloff rate of the filter 26 8 Wavef
94. scomp Electronic Design CircuitGear includes a small hardware module and display software that runs on a host PC Figure 1 shows the user interface 1 1 Oscilloscope The oscilloscope is a dual channel 20MSample sec oscilloscope with 10 bit A D conversion digital storage and display Channels A and B are sampled simultaneously and stored in the oscilloscope memory before being sent for display to the host computer Consequently the signals are always time aligned and associated with the same trigger signal Triggering is accomplished by digital circuitry so it is precise and consistent Trigger controls include Mode Auto Normal Single shot Manual Source A or B and Slope Positive or Negative The trigger point is continuously adjustable so that the operator can display the signal before and or after the trigger event The oscilloscope timebase frequency is derived from a crystal oscillator so it can be expected to be precise and stable The displayed amplitude is determined by 1 resistors and analog digital conversion The vertical preamplifier is gain switched to optimize the signal noise ratio and will accept x10 scope probes The initial software release includes basic oscilloscope functions Subsequent releases will include additional features such as spectrum analysis 1 2 Waveform Generator The waveform generator is a direct digital synthesis DDS based device with frequency range between 0 1Hz and 3MHz The frequency can b
95. ssential to use a probe that can withstand this voltage and it essential to ensure that the probe cannot inadvertently be switched to a times one setting Notice that the peak value of a sinusoidal voltage is 1 41 times the RMS value So a 117VAC line voltage will peak at around 170 volts e There must be no direct connection to the AC line If the equipment is line operated then it must be powered by an isolation transformer see above It is possible to obtain electronic probes that provide an isolation barrier between the line circuit and the oscilloscope For example the measurement signal is transferred from the AC line side to the oscilloscope side by means of an optically coupled circuit There is no electrical connection between the oscilloscope and the AC line The signal is transferred over a beam of light This method removes all possibility of short circuiting the line voltage to ground See for example http www powertekuk com 11 Overview of USB Operation In general the operation of the USB connection is seamless and invisible to the user Operation of the oscilloscope is usually as simple as plugging it in to an USB port and running the oscilloscope GUI software However it may be useful to understand some of the details The USB interface uses a USB Serial chip FT232BM from FTDI This chip with the appropriate driver software on the host PC emulates a serial port Consequently the Tcl Tk GUI software can access the hardw
96. t something like tt yUSBO or tt yUSB1 and so on 12 Troubleshooting 12 1 Microsoft Windows 12 1 1 Manually Assigning a COM Port Number in Windows XP It may be useful to know how to set the COM port manually 33 For example under certain circumstances it is possible for the operating system to assign a COM port number that too high to be usable by the host software In our situation here at the Syscomp factory we test each instrument by plugging it into a USB port Each time the operating system sees a new instrument it assigns it a new COM port number If the COM port number is greater than 9 it cannot be selected by the host software Then you must re assign the port number manually l Ze 10 11 Plug in the problem instrument to a USB port Go to Start gt Settings gt Control Panel gt System gt Hardware gt Device Manager Double click on Ports COM and LPT This opens to show any USB serial port assignments Let s say that it shows USB Serial Port COM12 This exceeds COMO so we have to manually reset the COM port number Double click on the entry USB Serial Port COM12 This opens a new dialogue box USB Serial Port COM12 Properties Select Port Settings and click on Advanced This opens a new dialog box Advanced Settings for COM12 In the upper left corner there is a scrollbox COM Port Number Use the up down arrows to scroll through the possible COM port assign ments For the new COM p
97. t to 2MHz 8 7 Waveform Format Waveform data files are stored in the same directory with the source code On a Windows machine the path to this directory would be something like C Program Files Syscomp CGR101 1 19 Source Waveform files end ina dat suffix for example sawtooth dat These are plain vanilla text files so they can be loaded into a text editor such as Notepad Each file consists of 256 entries X values Each of these 256 entries is the value of the waveform at that point Y value ranging from 0 most positive to 255 most negative Each entry value is terminated by a carriage return line feed pair Amplitude can be set by the CircuitGear generator hardware so it is best to scale the amplitude between 0 and 255 The CGR 101 does not contain offset hardware so any waveform offset must be included in the waveform description For example a logic waveform would have amplitude values ranging between 128 zero volts out and 0 maximum volts out If the waveform can be described by an equation you can use a spreadsheet to generate the corresponding waveform values Save the column of waveform file values as a csv comma separated values file Then examine the file using a text editor such as Notepad to ensure that there are no extraneous characters and the file For acoustical testing you will probably need a pink noise spectrum which rolls off the amplitude at 3db octave a 1 f characteristic It is also advis
98. tGear 15 xi Welcome to the Syscomp CircuitGear Setup Wizard This wil install Syscomp CircuitGesr 1 13 on your computer Itis recommended that you close all other applications before continuing Click Next to continue or Cancel to exit Setup a Welcome to Setup Wizard sur syscomp CroutGcor 19 Select Additional Tasks Which additional tasks should be performed y scomp CircuitGear ioj x Select Destination Location Where should Syscomp CircuitGear be installed Syscomp CircuitGear BSE Select Start Menu Folder Where should Setup place the program s shortcuts tJ Setup wil install Syscomp CircutGear into the folowing folder To continue click Next If you would like to select a different folder click Browse Browse Atleast 31 6 MB of free disk space is required Setup will create the program s shortcuts in the following Start Menu folder To continue click Next If you would like to select a different folder click Browse Browse mp Cicuiear 1 13 mes oe ee J b Select Destination top Syscomp CircuitGear 5 xi Ready to Install Setup ie now ready to begin nstaling Syscomp CircuitGear on your computer lt Back Cre gt Cancel c Select Start Menu Folder tup Syscomp CircultGear E palsies Installing Please wait while Setup installs Syscomp CircuitGiear on your computer Select the additional tasks yo
99. the AC line 10 1 Floating Power Supply Oscilloscope Power Line Ground Power Supply and II ip Computer Red joa Dannes i T Ground Black EOS oge beth A gt Figure 18 Floating Power Supply In this context floating power supply is one in which neither terminal is connected to the power line ground Consider the circuit shown in figure 18 Like many lab power supplies the power supply has three terminals positive negative and ground The ground terminal is connected to the third prong on the line cord which connects to the power line ground wire The oscilloscope has two connections the input terminal and ground terminal On the front panel BNC connector the inner contact is the input the outer ring is ground The ground connector finds its way to the AC ground line via the third prong on its line cord As shown in figure 18 either lead on the oscilloscope can be safely connected to the positive or negative ter minal of the power supply With proper care to avoid short circuits of the power supply this is a safe measurement situation 10 2 Grounded Power Supply Now consider that the negative terminal of the power supply is connected to its Ground terminal as shown in figure 19 32 Oscilloscope Power Line Ground Power Supply and TA Computer 1 de t a Seeesosou i E 1 Red Input re ars DE 1 i Black Ground l i rs e sy f
100. the instrument will not connect in this state You can change the permissions on dev ttyUSBO but the port is transient and disappears when you shut down or disconnect So you would need to do that every time you start the instrument To make this permanent add your name to the diaout group I tried to do it using the edubuntu system administration tool but for some reason the dialout group did not appear To do this the old fashioned command line way use the command groups to see which groups you belong to Probably dialout does not appear We will edit the groups file to add you Find the file et c group Probably read write permission is disabled for users on this file as well Make a note of the permissions because we ll change it back For example ls 1 etc group rw 1 root root 934 2008 05 22 10 17 etc group In order to edit it change the permissions to allow any user to edit that file using the command 47 sudo chmod 777 group lt your password here gt ls 1 etc group rwxrwxrwx 1 root root 954 2008 10 24 22 02 etc group Now you can edit and save the file Load that file into a text editor Find the line with dialout in it If the line ends in a colon that means that no one yet belongs to this group Add your login name If there already is some other login name add a comma and then your login name Here s what it might look like with me peter added to the dialout group after gabe man x
101. the lissajous figure will have multiple nodes In the early days of oscilloscopes lissajous figures were used in this manner for frequency measurement The vertical amplifiers of the day could not work at high frequencies so the signals were applied directly to the deflection plates of the cathode ray tube The lissajous figure gave an indication of frequency ratio and relative phase To form a complete lissajous loop the timebase setting must be such that both waveforms show at least one complete cycle Magnitude Measurement If the two signals are exactly in phase the XY plot is a straight line If the two signals are of exactly the same magnitude the angle of the straight line is 45 If the magnitudes are different then the line is at some other angle This is a sensitive method of comparing the amplitude of two waveforms which need not be sine waves Any waveshape should function in this measurement General Purpose Plotting The XY Mode display may be used for a variety of applications where a plot of some kind is required Figure 9 shows an example The CGR 101 has been configured to plot the voltage current curve of a silicon diode Notice that the diode threshold is around 0 6 volts The vertical scale is voltage measured across a current sensing resistance equivalent to 10mA per division 19 f Syscomp USB Digital Storage Oscilloscope DSO 101 E lol xj File View Tools Hardware Help Syscomp Digital Storage Oscilloscope
102. tyUSBx port is created you should be able to access that port without problems 11 Tf the file does not exist please let us know the name of the Linux distribution and we ll look for another solution 44 12 2 3 Setting Default Port Permissions to User Mode Suse 10 3 Suse in their wisdom have changed the method detecting USB devices Now USB devices do not exist in dev until they are plugged in Plug in the DSO 101 oscilloscope and execute dmesg You should see something like the following at the end of the message usb 1 2 new full speed USB device using uhci_hcd and address 2 usb 1 2 new device found idVendor 0403 idProduct 6001 usb 1 2 new device strings Mfr 1 Product 2 SerialNumber 3 usb 1 2 Product Digital Oscilloscope DSO 101 usb 1 2 Manufacturer Syscomp usb 1 2 SerialNumber DSQ307Z0 usb 1 2 configuration 1 chosen from 1 choice drivers usb serial usb serial c USB Serial support registered for FTDI USB Serial Device ftdi_sio 1 2 1 0 FTDI USB Serial Device converter detected drivers usb serial ftdi_sio c Detected FT232BM usb 1 2 FTDI USB Serial Device converter now attached to ttyUSBO usbcore registered new interface driver ftdi_sio drivers usb serial ftdi_sio c vl 4 3 USB FTDI Serial Converters Driver This indicates that the oscilloscope was detected and it has been assigned to the USB Serial port tt yUSBO You now go to the director dev and examine the tt yUSB
103. u would like Setup to perform while instaling Syscomp CircuitGeer then cick Next T Create a Quick Launch icon Click Install to continue with the installation or click Back if you want to review or change any settings Destination location C Program Files Syscomp CGR101 1 13 Start Menu folder Syscomp CircutGear 1 13 Extracting fles C Program Files Syscomp CGR101 1 13 Source Images 200us gi lt Back Newt gt Cancel d Additional Tasks Syscomp USB Device Driver Installer Welcome to the Syscomp USB Device Driver Installer This wizard wil walk you through pre instaling drivers on your computer To continue click Newt lt Back lt Back E instal e Ready to Install Syscomp USB Device Driver Installer Installing the ns for your Syscomp device is S Please wait while the drivers install This may take some time to complete lt Back Net f Installing Syscomp USB Device Driver Installer Congratulations You are finished installing drivers for your Syscomp device The divers were successfully installed on this computer You can now connect your device to this computer If your device came with instructions please read them first Driver Name Status Y FTDI CDM Driver Packa Ready to use Y FTDI CDM Driver Packa Ready to use g Welcome to Driver Install h Installing Drivers tup
104. ual operation of oscilloscope and signal generator here are some possible applications of the CircuitGear unit Logic Net The digital controls supply the functionality of a digital Exerciser Unit which can apply a stimulus to a digital circuit and measure the output For example the 8 bit digital lines can be used as inputs and indicators for a logic net Students set up various combinations of input signals to the net and record the outputs to generate logic equations or a truth table for the logic net State Machine Exerciser A single manual output line and the PWM output can be used as a pulser for counter and state machine circuits The manual output exercises the circuit at low speeds where the be haviour can be observed on the GUI indicators The PWM output is then used to operate the circuit at higher frequencies and the oscilloscope can be used to observe faster events Mixed Analog and Digital Circuits The digital outputs control a MDAC multiplying D A converter which sets the centre frequency of a bandpass filter The generator and oscilloscope function as a Vector Network Analyser showing how the frequency response changes as the digital value is adjusted Switching Power Supply The PWM output controls a power MOSFET and LC network which functions as a simple switching power supply Similarily PWM output can modulate the power to a DC motor as a simple method of speed control PWM DAC It is common for the PWM output of a microp
105. un the Syscomp software Select the menu item View gt Debug Console e A new window will appear which shows the commands being sent to the scope The scope is on Auto triggering by default Change this to normal triggering to stop the scrolling The window shows only commands being sent to the scope not the data being returned 53 15 2 CircuitGear ASCII Command Set For setup of the a terminal emulator to send these commands see section 12 1 5 on page 39 All commands must be terminated with lt carriage return gt character Optionally the command may be terminated with a lt carriage return gt lt line feed gt pair In the following commands the spaces are real and must be part of the command string Command i Info Identify Returns device identification string and firmware revision preceeded by and terminated by lt cr gt lt 1f gt Command W F F3 F2 F1 FO Waveform Set Frequency The parameters F3 FO are integer 8 bit numbers i e 0 255 representing the four bytes of the phase value The phase value is a 32 bit number The phase value is calculated as follows Phase value Output Frequency Hz 0 093 13225746 Hz where 0 093 13225746 is the resolution of the waveform generator Example for a 1kHz output Phase value 1000Hz 0 09313225746 10737 Break the phase value 10737 into four bytes 0 16777216 274 0 65536 216 41 x 256 23 241 1 2 The command wouldbeW F O 0 41 241 Command W A AU Wavefo
106. und scheme for your computer or configure the settings For al Figure 22 Control Panel 3 Ensure that the hardware unit DSO 101 oscilloscope WGM 101 waveform generator CGR 101 Cir cuitGear etc is plugged into a USB port In the System Properties Hardware panel of figure 25 there should be an entry Ports Double click on that and it should open to an entry like US B Serial Port COM amp LPT COM4 This specifies the COM port that should be selected in the Tcl Tk program in order to communicate with the USB hardware unit 12 1 4 Adjusting the COM Port Selection 1 Ensure that the hardware unit DSO 101 oscilloscope WGM 101 waveform generator CGR 101 Cir cuitGear etc is plugged into a USB port 2 In the System Properties Hardware panel of figure 25 there should be an entry Ports Double click on that and it should open to an entry like USB Serial Port COM amp LPT COM4 3 Double click on this last entry to obtain the Serial Port Properties screen of figure 26 37 F Add or Remove Programs ra 5 Currently installed programs T Show updates Sort by ame y Change or Remove 8 AFPL Ghostscript 8 51 Size 24 14MB Programs ES 48 arPL Ghostscript Fonts Size 5 47MB by S Arcade 3 0 Size 2 19MB Add New SEED p blaxxun Contact 1 31MB bl burst v3 1 0 5 48MB 19 pao 3 5 0 03MB Add Remove Windows 5 eMusic 50 Free MP3 offer 0 19MB Components 48 FTDI USB S
107. w Connected This is a Happy Moment because your computer is now talking properly to the oscilloscope hardware Operate the frequency amplitude or offset controls on the oscilloscope GUI As you do so the GUI sends commands to the hardware and you should see flashing from the Activity LED on the hardware front panel From now on it should be sufficient to boot up your computer plug in the oscilloscope and double click on the desktop icon for the oscilloscope 4 2 Macintosh Install This section describes how to install Syscomp instruments on a MacBook running OSX These instructions de scribe a new one button procedure for software version 1 13 and following This procedure is much simpler than the previous version Notice that it is not necessary to download and install the Tcl Tk language software The Syscomp software uses Tcl Tk but the language is bundled with our software and automatically installed with our software If you wish to experiment and modify the source code then you will need to install Tcl Tk separately Few people do that 4 2 1 Checking the Host Machine The Syscomp software is interpreted by the Tcl Tk language interpreter so it is essential that the machine is capable of running Tcl Tk The ActiveState website originators of Tcl Tk indicate that Tcl Tk should run correctly on platforms with Mac OS X 10 2 There is no mention of requirement for Intel or Power PC processors The first step
108. yon must be properly configured to be used This is described in the document Seyon Quick Start Guide which is on the system CDROM 58 Information on using minicom may be found at the following location Using Minicom and Seyon Chapter 11 of Learning Debian GNU Linux Bill McCarty O Reilly Books 1999 http www oreilly com catalog debian chapter book ch11_07 html 1 Plug the scope hardware into a USB port on the computer 2 Run the command dmesg to identify the serial port that the is allocted to this USB device It may be a few seconds before the operating system finishes its allocation so run dmesg repeatedly until you see the serial port number which will be something like tt yUSB1 3 Start the terminal communications program Seyon or Minicom 4 Set the port settings to Bits per Second 230400 Data bits 8 Parity None Stop Bit 1 Flow Control Hardware If you have a version of the oscilloscope Tcl program that works correctly with the scope hardware you can verify the baud rate Load that code into a text editor and look for the baud setting Search for a variable baud or a procedure openSerialPort 5 Issue some command from the list in section 15 2 Type it in followed by the Enter key A good choice is i which should result in a message from the oscilloscope indicating its version number Now you can type in other commands 17 Modifying the Tcl Tk Software The host software for the scope and ot

Syscomp Computer Controlled Instruments CGR

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