Home

the Hardware Manual

Contents

1. trigger hysteresis trigger moment beginning t 0 of of record record start of measuring The input signal is compared with two levels in the trigger system the arming level and the firing level When the input signal passes the arming level the trigger system is armed If the input signal passes the firing level the trigger system becomes active and fires a pulse This pulse is used to start the display of the signal The arming level and the firing level are coupled to each other by the trigger hysteresis and their level is determined by the trigger level The firing level corresponds to the trigger level The trigger hysteresis defines at which signal size change can be triggered the change has to be that large that both levels are passed With a small trigger hysteresis it is possible to trigger on small signals If a signal contains a lot of noise a small trigger hysteresis causes triggering on the noise instead of the original signal which gives an unstable display A trigger hysteresis larger than the noise level is then necessary In the illustration a signal and the two levels are displayed In this case it is triggered on the rising slope of the signal The signal passes the two levels from low to high When triggering on the falling slope of a signal the two levels are swapped Then the signal has to pass the two levels from high to low to generate a trigger Selecting the trigger source The trigger syste
2. In both modes the measurement values are preceded by a block of information In that block is indicated how the channels are set and how the high low and relative levels are set Each measurement is preceded by the time and date of the measurement If a measured value is larger than the selected input range is displayed This will also be stored on disk or sent to the printer The date time format can be set through the program settings dialog The Voltmeter 54 DI 770 and WINDAQ Scope Manual 8 The Data Logger For measuring slowly changing signals e g the temperature change in a room the data logger is the most suitable instrument The data logger is a two channel direct registering measuring instrument displaying the changes of the input signal graphically on the screen or on paper The data logger measures at settable fixed times and processes the measured value if necessary The number of mea surements to be taken is also settable Note The data logger displays each measured sample immediately the oscilloscope first takes all samples and then displays the complete record The data logger measures the input signals at adjustable times The time between two measurements is adjustable from 0 01 second to 500 seconds The number of samples is also adjustable from 1 to 32760 The maximum measur ing time is 500 sec x 32760 samples 16380000 seconds 189 6 days Note Due to the different way of measuring t
3. The available window types are rectangular all data is not changed Hanning sinusoidal Hamming sinusoidal Bartlett sinusoidal Blackman triangular Parzen triangular Performing measurements When all settings are made measurements can be made Start and stop measuring To avoid a new screen of measurement data replacing an old screen measuring an displaying of data can be stopped This can be done in several ways by pressing the Pause button 00 by pressing the lt S gt key of by activating the item Stop continuous measuring from the Measure menu When measuring is stopped the latest measured data will remain on the screen The Pause button changes to a Play button d e and the One shot button Me becomes available The measured signal can now be examined Single measurements To perform a single measurement press the One shot button press the lt O gt key of activate the Perform a single mea surement item from the Measure menu When in the Spectrum analyzer averaging is selected there will be performed as many measurements as there are set for the averaging and then measuring will stop Continuous measuring can be started again by pressing the Play button the lt S gt key or the item Start continuous mea suring from the Measure menu The One shot button will be disabled again Averaging When a noisy signal is measured the influence of the noise can be eliminated by averaging several spectra The no
4. ea a a tea id t Tapparem 4 ms J The input signal is a triangular signal with a frequency of 1 25 kHz upper most in the illustration The signal is sam pled at a frequency of 1 kHz The dotted signal is the result of the reconstruction From that triangular signal the peri odical time is 4 ms which corresponds with an apparent frequency alias of 250 Hz 1 25 kHz 1 kHz no To avoid aliasing the sample frequency must be higher than 2 times the maximum frequency of the input signal Introduction 2 DI 770 and WINDAQ Scope Manual Aliasing is not always visible on an oscilloscope In the latter illustration it gives a good looking picture It is not apparent that aliasing occurs The next illustration gives an example of visible aliasing This time it is a sine wave signal with a frequency of 25 7 kHz which is sampled at a frequency of 5 kHz The mini mal sampling frequency should have been 51 4 kHz For proper analysis the sampling frequency should have been 500 khz Digitizing After taking a sample of the input signal it is digitized This is done with an Analog to Digital Convertor ADC The ADC converts the size of the signal to a digital number This is called quantifying The first condition for accurate measurement is to have as many as possible quantifying steps This can be realized by using an ADC with a resolution as high as possible The resolution of ADC s is often given in bits The number of
5. Controlling the function generator Signal shape cine Triangle Square oc white noise File With the signal shape selector buttons the signal type can be set Possible signals are Sine a sine wave is generated Triangle a triangle wave is generated Square a square wave is generated DC a constant DC level is generated White noise a white noise is generated File a signal from a file is generated The signal type File is discussed later Frequency In the Frequency box all controls for adjusting the signal frequency are located Seven decade buttons set a frequency range in which the frequency can be set using the slider Each range runs from 0 2 to 2 times the value on the button When the signal shape is set to DC the frequency adjustment is disabled Symarnetry a J gt The symmetry of a signal indicates the relation between the length of the positive part of the period to the total length of the period A symmetry of 50 means that the positive part is exactly half of the total period Symmetry Using the slider in the Symmetry box the symmetry can be adjusted between 1 and 99 The Mid button sets the symmetry to 50 the centre position When the signal shape is set to DC or White noise the symmetry adjustment is disabled The Function Generator 70 DI 770 and WINDAQ Scope Manual Amplitude Amplitude 0 7 10 12 4 Y The amplitude of the output signal can be adjusted in three ranges
6. DATAQ INSTRUMENTS The way PC based instrumentation should be DI 770 and WINDAQ Scope Oscilloscope and supporting software User s Manual Manual Revision F Software Release Level 1 Copyright 2005 by DATAQ Instruments Inc The Information contained herein is the exclusive property of DATAQ Instruments Inc except as otherwise indicated and shall not be reproduced transmitted transcribed stored in a retrieval system or translated into any human or computer language in any form or by any means electronic mechanical magnetic optical chemical manual or otherwise without expressed written authorization from the com pany The distribution of this material outside the company may occur only as authorized by the company in writing DATAQ Instruments hardware and software products are not designed to be used in the diagnosis and treatment of humans nor are they to be used as critical components in any life support systems whose failure to perform can rea sonably be expected to cause significant injury to humans DATAQ the DATAQ logo and WINDAQ are registered trademarks of DATAQ Instruments Inc All rights reserved DATAQ INSTRUMENTS DATAO Instruments Inc 241 Springside Drive Akron Ohio 44333 U S A Telephone 330 668 1444 Fax 330 666 5434 Designed and manufactured in the United States of America Warranty and Service Policy Product Warranty DATAQ Instruments Inc warrants that this hardwar
7. Note The outside of the external power connector is connected to 5 Volt In order to avoid shortage first connect the cable to the DI 770 and then to the keyboard connector Center Pin 1 3 mm Ground Outside bushing 3 5 mm 5 VDC Connections 13 DI 770 and WINDAQ Scope Manual 5 WINDAQ Scope Software This manual expects that the reader has a basic knowledge how to control applications running under windows work ing with menus in windows applications etc ek eee PA O O Ge ae ae LS File feeasure Chi ai Time base T Cursors Math References aes Pelp i Bi a 20 O0kS ec 4 00 Om uE Tera ao eee eS eee o A e a 1 000 1 000 5 00m 10 00m 15 00m 20 00m 25 00m 1 Set the trigger level the trigger hysteresis and the trigger slope by dragging and double clicking Press the right mouse button and setup the complete trigger system 2 Toggle auto ranging for channel 1 Press the right mouse button and select an input sensitivity from a menu 3 Toggle the invert for channel 1 4 Set the signal coupling for channel 1 to AC or DC 5 Copy show save and load reference signals 6 Select a math channel 7 Toggle envelope mode Software 15 DI 770 and WINDAQ Scope Manual 8 With the auto setup the oscilloscope sets itself according the input signal 9 Switch between a number of pre defined offset and gain settings for channel 2 Press the right mouse button and select the settings from a
8. Setting the horizontal position of the signal s When a record view gain gt 1 is selected only a part of the record is visible To view a certain part of the record a record view offset can be applied Applying a record view offset can be done by means of the special record view scroll bar and by means of a menu To use the menu enter the Time base menu and select the Record view offset item A dialog box will appear in which the record view offset can be entered in seconds When the trigger position is not equal to 0 a negative value will make pre samples visible a positive value will make post samples visible The Time base menu can also be entered by pressing the right mouse button over one of the time base controls or read outs When the record view gain is equal to 1 0 the Record view offset item is not available in the menu The record view scroll bar For an easy way of adjusting the record view gain and the record view offset the oscilloscope is equipped with a spe cial record view scroll bar located under the signal display ss The dark gray part of the scroll bar represents the measured record the slider light gray represents the visible part of the record The red lines represent the position of the cursors If the cursors are not switched on no red lines are visi ble To change the record view gain place the mouse pointer on the left hand side or the right hand side of the slider the mouse pointer will ch
9. This is only a minor problem The software detects that it has missed samples and will warn the user by lighting up a red LED in the display and displaying a warning message in the hint bar Note The missed sample in the record is filled with the value of the previous sample Note Trying to reload the missed sample s would take so much time that again samples would be missed When the total measurement is ready the software will reload the complete measured record from the hardware acquisition memory and display it Hint There are a few things to make the software keep up with the hardware longer make the data logger window as small as possible Select Scan mode instead of Roll mode Do not show references while measuring close all other applications especially applications in DOS windows Set the Windows video driver to display up to 256 colors instead of True color or High color Displaying channels The two channels can be measured in several different ways only channel is measured and displayed only channel 2 is measured and displayed Chl and Ch2 channel 1 and channel 2 are measured and displayed simultaneously Selecting which way to measure the channels can be done using the Measure menu When only one channel is measured the controls of the other channel are disabled or removed from the display Setting up a channel Setting up a channel in the data logger is done in the same way as in the oscilloscope
10. lt Alt gt gt Move the right side of the record view scrollbar to the right lt t gt Move the record view scrollbar to the left lt gt gt Move the record view scrollbar to the right lt A gt Set the signal coupling of channel 1 to AC lt Shift A gt Set the signal coupling of channel 2 to AC lt D gt Set the signal coupling of channel 1 to DC lt Shift D gt Set the signal coupling of channel 2 to DC Toggle Envelope mode Toggle invert of channel 1 oscilloscope and data logger lt Shift I gt Toggle invert of channel 1 oscilloscope and data logger A A yes ae lt L gt Switch the vertical axis of channel 1 between Linear and Log spectrum analyzer lt Shift L gt Switch the vertical axis of channel 2 between Linear and Log spectrum analyzer reseteo Main aes panama CO reee EC IN sans CO TT 25 Sieh XY mw oop e weereens Software 20 A gt DI 770 and WINDAQ Scope Manual Switch channel one step less sensitive lt F7 gt Switch channel 2 one step more sensitive lt F8 gt Switch channel 2 one step less sensitive lt F11 gt Make the record length one step shorter lt F12 gt Make the record length one step longer Controlling with the mouse All objects in the instrument windows give access to the corresponding settings by clicking the right mouse button on the objects A popup menu will appear in
11. 0008 A 22 dBm L D v 0 OOE 5 010 0 000 1 0000 000 Of all four instruments the voltmeter has the lowest settings priority This means that if for example the oscilloscope is active the record length pre samples and post samples of the oscilloscope are used in the voltmeter The voltmeter only uses post samples to perform the calculations If less than 200 post samples are available no calculations are done and a message is displayed The only setting that can be changed by the voltmeter when the oscilloscope or spectrum analyzer is active is the sample frequency The measure system of the voltmeter The voltmeter takes 200 samples of the input signal with a certain sample frequency These 200 samples are used to perform several calculations The Voltmeter 45 DI 770 and WINDAQ Scope Manual The voltmeter has a limited frequency range in which the measurements are performed correctly If the periodical time of the input signal is much larger than the measuring time a wrong value is measured See the next illustration Peak Peak value 200 samples If the time in which the 200 samples are taken is too long in relation to the periodical time of the input signal aliasing can occur see also the chapter about the oscilloscope Setting the frequency range To avoid errors like the ones mentioned above the frequency range of the voltmeter has to be set properly The sam pling frequency i
12. 256 Kwords digital 2 levels CH1 CH2 AND OR digital external rising slope falling slope inside window outside window peak 0 100 of full scale 0 100 of full scale 0 025 12 bits 0 131060 samples 0 100 one sample resolution 0 131060 samples 0 100 one sample resolution 0 3 3 volt 5 volt max 500 mAmp max 2 5 Watt max 1500 mAmp max 7 5 Watt max 1 0 x 6 7 x 5 2 in 25 x 170 x 140 mm approx 2 pounds 10 ounces 1190 grams 1 8 meter 70 inch BNC BNC BNC USB 2 0 and USB 1 1 type A Sub D 25 pins female Specifications 8 DI 770 and WINDAQ Scope Manual System Requirements PC I O connection USB 2 0 or USB 1 1 port type A Operating system Windows 98 2000 ME XP Operating Environment Ambient temperature 0 to 55 C Relative humidity 10 to 90 non condensing Storage Environment Ambient temperature 20 to 70 C Relative humidity 5 to 95 non condensing Certifications and Compliances CE mark compliance CE Package Instrument DI 770 Accessories 2 oscilloscope probes 1 1 1 10 switchable Software Windows 98 2000 ME XP on CD Drivers Windows 98 2000 ME XP on CD Manual printed on paper and digital on CD Specifications 9 DI 770 and WINDAQ Scope Manual 3 Installation The DI 770 is an external measuring instrument which can be connected to a PC The DI 770 is connected to a USB port of the PC using the attached cable The DI 770 does not need an
13. 90 and 100 When the mouse sensitivity is set to 100 steps per screen each mouse movement will result in a pre trigger value change of 1 Note The mouse sensitivity does not affect adjusting the pre trigger value by clicking the buttons of the scroll bar or by clicking in the scrollbar outside the slider To set the Mouse sensitivity enter the Time base menu and select Mouse sensitivity pre trigger position adjustment In the menu that pops up the choices are available Magnifying the horizontal axis The software supports a wide range of record lengths which can all been viewed completely A special displaying algorithm guarantees that when ever the record length is larger than the display size no amplitude information will be lost To take a closer look at a smaller part of the record that part can be magnified to fill the screen This is done with the record view gain which is completely variable between 1 0 full record view and a value depending on the instru ment window width about 40 about 80 Adjusting the record view gain can be done through a menu and by means of the special record view scroll bar To change the record view gain by means of a menu enter the Time base menu and select the Record view gain item This will bring up a dialog box in which the requested record view gain can be entered The Time base menu can also be entered by pressing the right mouse button over one of the time base controls or read outs
14. It contains the device drivers for the DI 770 If your Windows auto play feature is enabled the WINDAQ Software Installation will start Click on the Exit but ton to leave the installation 3 Click through the defaults to install the Driver Note If you receive the Microsoft issued warning that the software has not passed Windows Logo testing to verify its compatibility with Windows XP click Continue Anyway to continue with installation 4 After the Driver is installed click Finish to close the Found New Hardware Wizard Windows should prompt you that the device has been installed properly Hardware Installation 11 DI 770 and WINDAQ Scope Manual Installing WINDAQ Scope Software The WINDAQ Resource CD ROM contains all the software required for use with your DI 770 instrument l Ze 10 Re insert the WINDAQ Resource CD for the auto play feature to run or run the Setup application In the What do you want to do window select Install Software and click OK In the Installing Software window select Install Software for all other products and click OK From the list provided select WinDaq Scope for DI 770 and click OK In the Welcome box click OK to continue Read the License Agreement If you accept the terms click Accept and Continue If you choose not to accept this will end the installation When prompted specify the directory where you want to install the softwar
15. available Each cursor pair exists of a hori zontal and a vertical cursor that can be placed anywhere inside or outside the signal display Where the two cursors cross each other a link is made For the left cursor this link is pink for the right cursor this link 1s black Switching on cursors To switch on cursors enter the Cursors menu and select the Large cursors item or the Small cursors item Large cur sors are drawn from the left to the right hand side of the signal display or from the top to the bottom of the signal dis play Small cursors only form a small cross The Cursors menu can be found in the main menu or can be called by clicking the right mouse button in the signal display When the cursors are switched on a special cursor readout win dow appears as well The cursors are waveform based This means that the cursor position is related to the waveform If the record view offset or record view gain is changed the cursor position will remain at the same position in the waveform If the input sensitivity the software offset or software gain is changed the cursor will stay at the same voltage level Because of this cursors can get off screen In the record view scroll bar two red lines are drawn to indicate the posi tion of the cursors in the record To position a cursor bring the mouse pointer on the cursor to position The mouse pointer will change shape alle position a horizontal cursor t position a vertical cursor p po
16. called the Record length To change the record length two ways are available by means of a menu or by means of function keys To change the record length using the menu enter the Time base menu and select the Record length item Another menu will pop up containing the available record lengths and an item for a user defined record length Selecting this item will bring up a dialog box in which a self defined record length within the instrument hardware limits can be The Oscilloscope 35 DI 770 and WINDAQ Scope Manual entered The Time base menu can also be entered by pressing the right mouse button over one of the time base con trols or read outs For changing the record length the following function keys are available Select a shorter record length Select a longer record length Selecting another record length will change the total measure time but the pre trigger value will keep the same value Setting the pre trigger value The oscilloscope is equipped with a trigger system This trigger system monitors the input signal s and determines based on the settings of the trigger system and the input signal when measuring and displaying the signal s has to Start The moment of trigger the trigger point can be placed at any position in the record with measured data This will result in a certain number of samples before the trigger point pre samples and a number of samples after the trigger point post samples Pre and
17. characterized best by their frequency behavior That frequency behavior is best obtained by observing the electrical signals in the frequency domain To display the frequency domain an instrument is needed that can distinguish different frequencies from each other and measure the signal size at the different fre quencies An instrument that can display the frequency domain is the spectrum analyzer It graphically displays volt age as a function of frequency __ Spectrum analyzer Fie Measure Chi he Frequency axis Cursors Ali settings Help Si2samles SS ETITE 200 of 200 25 00MS sec Rectangle 25 46 35 46 45 45 55 46 55 46 75 46 O 250M E 00M 7 50M 10 00M 12 50M AA In the time domain all frequency components of a signal are seen summed together In the frequency domain com plex signals signals composed of more than one frequency are separated into their frequency components where the voltage of each component is displayed The frequency domain contains information which is not available in the time domain Therefore the spectrum ana lyzer has certain advantages compared with an oscilloscope e With a spectrum analyzer small harmonic distortions on a signal can be displayed better than on an oscilloscope A sine wave may look good in the time domain however in the frequency domain the harmonic distortion is vis ible e A noise signal may look fully random in the time domain in the frequency domain it can appear
18. correspond to the left and right cursor Calculate values If this option is disabled no new calculations will be done until the option is enabled Show measurement name Show measured value Show measurement unit To reduce the space used by the window on the screen the measurement name value and or unit can be hidden This results in the disappearance of the corresponding column which results in a smaller window Display font By selecting this option the font which is used to display the strings and values can be changed The font settings which can be changed are font name font style font size and the font color Background color By selecting this option the background color can be changed Some font colors like e g light green are not show ing up very good on a white background Change the background color to e g black for a better result The Spectrum Analyzer 68 DI 770 and WINDAQ Scope Manual 10 The Function Generator The DI 770 is also equipped with a function generator a Function generator Sine Triangle Synimet Square pe orsel DC Amplitude While noise Frequency File FraQquert AT Iiu de ap 0 100 ie ros er 205 i i5 3 i 7 10 12 metry Sn DC ofset Output store j L 4 C ee ET With the function generator signals of various shapes with adjustable frequency symmetry amplitude and offset Next to that the function generator contains a sweep generator which can in combin
19. dragging the trigger hysteresis 1s adjusted according the size of the trigger symbol When the mouse button is released trigger hysteresis adjustment stops and the normal mouse pointer shape is returned To adjust the trigger mode using the trigger symbol place the mouse pointer on the trigger symbol and double click the left mouse button The trigger mode will change from Falling slope to Rising slope Rising slope to Falling slope The trigger time out When the input signal does not meet the trigger conditions no new measurement data will be displayed and the last displayed signal will remain on the screen This can be very inconvenient with unknown signals since it is not known how the trigger system has to be set To provide in that case for a representation of the input signal on the screen a trigger time out setting is available With the time out setting it is determined how long the delay will be for a trigger pulse If that time expires a trigger pulse is forced by the software and the available data will be displayed This will not result in a stable display but it will give an impression how the trigger has to be set To set the trigger time out enter the Trigger menu and select the Time out item An input dialog will come up in which the time out time can be entered in seconds When a time of zero is entered there will be no trigger time out but no triggering as well As soon as a signal is dis played the instrumen
20. is displayed but the data is kept in memory When the record length is changed to a longer record the part of the reference channel that was not filled is filled with zeroes Switching references on or off Switching a reference channel on or off can be done by selecting the item Display Refx from the Reference menu where x stands for or 2 It can also be done by means of a button on the speed button tool bar for reference 1 and for reference 2 When a button appears to be pressed the corresponding reference is switched on Scaling references When a reference channel is filled the data remains the same until new data is stored in the reference channel When the input sensitivity the software offset or the software gain for the corresponding channel changes the reference channel will not change It can be useful that when a signal is copied to a reference channel to compare live measurements with that reference channel that the settings of the reference channel will follow the settings of the live channel So when e g the input sensitivity of the live channel changes the reference channel is scaled in such a way that the live channel and the ref erence Channel can still be compared on a 1 1 base To do that select the item Scale references from the Reference menu Any change of the input sensitivity the soft ware offset or the software gain of a channel will also be applied to the reference channel When scaling references is sw
21. is the voltage level which a signal drops or gains per millisecond Slew rate right the slew rate of the signal at the position of the right cursor is determined Phase difference These measurements are only available when both channels are switched on They measure the phase angle differ ence between the signals on channel and channel 2 When the software can not detect a complete period of the sig nal on both channels or when the frequency of the two signals are different no phase difference is determined Degrees The angle is presented in degrees Radials The angle is presented in radials cos The cosine value of the angle is presented Set impedance value The dBm and power measurements require a reference resistance The value of the resistance can be set using this menu item The value has to be entered in Ohm and is default 600 Automatic correct points By selecting this option the automatic correction of the cursors to the nearest zero crossing is enabled or disabled The right cursor is positioned one or more periods from the left cursor To determine a frequency or duty cycle posi tion the right cursor at the end of the second period or further for correct results Automatic tracking cursors If this option is enabled the voltage levels of the cursors are automatically set to the voltage levels of the sample numbers which correspond to the left and right cursor Calculate values If this option is disabled no new calcu
22. measurement may not be electrical the physical variable is often converted to an electrical signal with a special transducer Common transducers are accelerometers pressure probes current clamps and temperature probes The advantages of converting the physical parameters to electrical signals are large since several instruments for examining electrical signals are available The DI 770 is a two channel 25 or 100 M samples sec measuring instrument With the accompanying software the DI 770 can be used as an oscilloscope a storage oscilloscope a spectrum analyzer a true RMS voltmeter or a data logger All instruments measure by sampling the input signals digitizing the values process them save them and dis play them ATTENTION Measuring directly on the LINE VOLTAGE can be very dangerous The OUTSIDE of the BNC CONNECTORS at the DI 770 are connected with the GROUND of the computer Use a good isolation transformer or a differential probe when measuring at the LINE VOLTAGE or at GROUND ED POWER SUPPLIES In case this has not been considered and the GROUND of the DI 770 is connected to a positive voltage a short cir cuit current will be flowing Because of this short circuit current both the DI 770 and the computer can be damaged Safety Before you start working with the DI 770 first read these safety rules e Avoid working alone e Check the probes test leads for damages Do NOT use them if they are damaged e Take care when
23. menu 10 Adjust the pre trigger point Press the right mouse button and setup the complete time axis 4 F F T AAA ES Fie Measure Acquisition Settings Help male Channel 1 sensitivity 8 00 SEUL 2 sensitivity 2 000 True RMS dam 58 Ta 4553 asm p E Frequency 19735 tn D COO 0000 000 1 The bar graph of display 2 of channel 1 for a quick indication of the signal size 2 Display 1 of channel 1 press the right mouse button to setup the display 3 Reset the minimum and maximum values 4 Stop the measurements with this button 5 Perform a single measurement with this button 6 Perform a measurement at settable times and send the result to the printer 7 Perform a measurement at settable times and store the result on disk 8 Switch the channel 2 signal coupling to AC or DC Software 16 DI 770 and WINDAQ Scope Manual D 6 4 5 ITA a 7 E File Measure Chi Che Tmebase Cursors References Setirgs Help PA pee LJ ee eT 1500 samples 500 00msec 200 00 1 i 0 00 10 100 00 SEn o E pan ce ee oes mes ee 10 2 000 00 p m m 16 93 97 0 54 20 00 15 43 37 0 1858 9 97 8 54 36 00 j Drag this end of the axis and adjust the gain of channel 1 Press the right mouse button and setup channel 1 With the Stop button the data logger is stopped Start a measurement with the data logger Zoom in to a sp
24. no longer be set Note When the spectrum analyzer is set to Hold and the frequency axis is set to octaves or third octaves the signal will not match with the axis and the grid until a new measurement is taken Setting the frequency range The frequency range can be set in two ways using the menu of by means of special function keys The frequency range is determined fully on the sample frequency the frequency range is half of the sample fre quency To change the Frequency range using the menu enter the Frequency axis menu and select the Frequency range item A new menu will appear with all possible frequency range settings The Frequency axis menu can also be entered by pressing the right mouse button over one of the frequency axis controls or read outs The last item in the menu is a user defined setting Activating this item will bring up a dialog box in which a self defined frequency range within the instrument hardware limitations can be entered Due to the way the sample fre quency is generated in the hardware not all frequencies and thus not all frequency ranges can be generated If an invalid frequency range is entered the closest valid frequency range will be generated The following keys can be used to change the frequency range Set the frequency range one step smaller Set the frequency range one step larger Setting the spectrum record length The spectrum analyzer takes a number of samples to determine the frequenc
25. not attenuated 20 dB attenuated or 40 dB atten uated With the slider a voltage between O Volt and 12 Volt or O Volt and 10 Volt depending on the instrument can be set DC offset DC offs et le a ae It is possible to add a DC offset to the output signal In the DC offset box there is a slider for the amplitude of the off set The button will set the DC offset back to zero When the signal shape is set to DC the slider is used to toggle the polarity of the DC signal Numerical input All described functions can also be controlled using the keyboard When the window is expanded a small key pad is located which enables entering all settings This key pad can be controlled by mouse but also with the keyboard of the computer In that case the window doesn t need to be expanded The top four keys indicate which setting will be adjusted The corresponding reading in the display will start blinking Also the numerical keys will be enabled and the required value can be entered The input can be ended by pressing the lt Enter gt key The following keys are available Adjust the symmetry of the signal Adjust the DC offset of the signal fo lo The Function Generator 71 DI 770 and WINDAQ Scope Manual Adjust the amplitude of the signal Adjust the frequency of the signal Add this figure to the entered number Add a decimal point to the entered number Reverse the polarity of the entered number Terminate th
26. of measure just type a string with a maximum length of five characters Change the units per measurement unit Using the edit box Units per measurement unit the number of units per selected unit can be set In the edit box the multiplication factor can be entered The measured value is multiplied by the factor and displayed This can be used if e g a 1 10 probe is used To correct the reading enter a value 10 in the edit box Relative measurements The voltmeter can take absolute measurements and relative measurements When measuring absolute the measure ments are related to the 0 level ground When measuring relative the measurements are related to a settable value This value is subtracted from the measured value by the software This means that before displaying the value in the display the relative value is subtracted from the calculated value The Voltmeter 51 DI 770 and WINDAQ Scope Manual The value can be set by entering a value in the Set relative value edit box The value has to be entered in volts To enable relative measurements a checkmark has to be placed after Relative measuring Relative measuring is then enabled Relative measurements can be used with e g a temperature measurement Suppose the output voltage of a tempera ture probe at O degrees Celsius equals 10 volt By entering a relative value of 10 volt the absolute temperature is directly readable Comparison measurements For displaying the me
27. post samples together form the record length The position of the trigger point is referred to as the pre trigger value indicating how many pre samples are recorded in the total record Usually and default this number is given in a percentage of the record length but it can be given in a number of samples or in a time value as well To change the pre trigger value two ways are possible by a menu or with the special trigger position scroll bar which is located below the signal display a 2 E This special scroll bar represents the complete record and the slider represents the trigger point In the above pic ture the trigger point is set to 25 To change the trigger point place your mouse pointer over the arrow the mouse pointer will change shape press the left mouse button and drag the slider to the position you want it to have When one of the small buttons at the left hand side or the right hand side of the scroll bar are clicked the pre trigger value will change by 1 When the mouse is clicked within the scroll bar but not on the slider the pre trigger value will increase or decrease by 5 depending on whether the mouse is clicked to the right or to the left of the slider When the mouse button remains pressed an auto repeat function will be activated To change the pre trigger value by using the menu enter the Time base menu and select the Pre trigger value item this will bring up a menu with 5 pre trigger value opti
28. sets the sensitivity for both channels to auto ranging so the optimal signal size is obtained Also the trigger level of the channel that is the trigger source is set to auto level to insure there is always a trigger Then the time base is set in a way that the signal at the channel that is triggered on is displayed with 2 to 6 periods The auto setup function does nothing to the signal coupling the measure mode ch1 ch2 or ch1 and ch2 or the trig ger source The Oscilloscope 41 DI 770 and WINDAQ Scope Manual Zooming When a certain part of the screen has to be enlarged to full screen the zoom function is the easiest way to do that The zoom function is activated by pressing the zoom button a This button stays down until the zoom function is finished When the zoom function is activated a rectangular area in the signal display can be selected with the mouse Place the mouse at one of the corners of the rectangle press the left mouse button keep it pressed and drag the mouse to the opposite corner of the rectangle While dragging a dashed rectangle is drawn When the rectangle has the correct size release the mouse button The zooming function will finish and the software offset and gain of both channels and the record view offset and gain are adjusted to the values that result in viewing the selected part of the screen Performing cursor measurements To perform measurements on the measured data two pairs of cursors are
29. slower and check whether the signal at the display changes accordingly If that does not give any clearance you can determine the frequency of the input signal with the spectrum analyzer Therefore you must set the frequency range of the spectrum analyzer to the maximum to avoid aliasing with the spectrum analyzer For more information see the chapter Spectrum Analyzer Displaying channels The oscilloscope has several modes to display the two channels To select the measure mode enter the Measure menu and select measure and display only channel 1 measure and display only channel 2 Chl and Ch2 measure channel 1 and channel 2 simultaneously and display the values of both channels Note When the measure mode Chl and Ch2 is selected displaying math signals becomes available When only one channel is measured the controls of the other channel are disabled or removed from the display Envelope mode When a signal is monitored and a glitch is expected envelope mode can be switched on to be sure to see the glitch In envelope mode for each sample in the record a highest value and a lowest value is stored Each measurement is checked whether the new value lies between the previous highest and lowest or not If not the highest or lowest value The Oscilloscope 30 DI 770 and WINDAQ Scope Manual is changed to the new value Then a vertical line is drawn between the lowest and highest value So a glitch is always captured Envelop
30. switched on by activating the play button or pressing the lt S gt key Storing measurement values on disk or paper The voltmeter can store measurements on disk or print them This is done in a completely different way than the other instruments The voltmeter can be set to measure acquire at fixed times The measured value will then be stored on disk or sent to the printer The time at which measurements are taken is not 100 guaranteed The reason for this is the Windows environment which is not a real time multitasking system Because of this there is no guarantee that the time between two mea surements is the set interval If this occurs close all windows programs except the voltmeter and then try again Setting the time between two measurements By activating the choice Time from the Acquisition menu the time between two measurements can be set A dialog box appears in which the time in seconds can be entered Note When a time shorter than 0 5 seconds is entered the acquisition speed is determined by the changes of the dis plays Setting the hysteresis With an acquisition time smaller than 0 5 seconds the acquisition speed is determined by the changes in the displays It can occur that the input signal has a value just between two displayable values In that case the display will con stantly change between the two values To avoid a constant storage to disk or printer in that case a hysteresis can be set Only when the inpu
31. the screen and ch2 uses the lower half of the screen the math channel comes in the center of the screen The math channel can be switched off again by selecting the item No math from the Math menu The Oscilloscope 31 DI 770 and WINDAQ Scope Manual Setting up a channel The two channels of the oscilloscope are completely configurable Both channels are identical each has its own menu item in the main menu Since the possibilities for both channels are equal channel 1 is explained here Where channel 1 is described the same applies to channel 2 With the menu item Ch1 or Ch2 from the main menu a popup menu is called with all settings for a channel Setting the sensitivity of a channel The input sensitivity of a channel determines how large a certain signal will be displayed the lower the full scale value the larger the signal will be displayed It is also possible to enable an autoranging function The sensitivity can be set through the Sensitivity menu The Sensitivity menu is called by enabling the Chl menu and then selecting the Sensitivity menu In this menu the input sensitivities are available Also an Autoranging setting is available The Sensitivity menu can also be entered by clicking the right mouse button over one of the Chl or Ch2 controls and readouts To switch on Autoranging a special button is available When auto ranging is switched on the button caption is Auto otherwise it holds the current set input sensi
32. time right sample time difference cursor frequency Voltage left Voltage right Voltage dif ference slew rate left slew rate right fase difference in Degrees Radials or cos Specifications 5 DI 770 and WINDAQ Scope Manual Color settings Fonts Voltmeter Display channels Display size Number of displays Frequency range Full scale reading Accuracy DC coupled Accuracy AC coupled Measurements Display mode Measure units Relative Sound settings Data storing Acquisition hysteresis Transient Recorder Measuring channels Measuring points Measure time between to points Measure time span Measure mode Cursor readout Time reference Spectrum Analyzer Display channels Display mode Measuring mode Vertical position setting Vertical gain setting CH1 CH2 Ref CH1 Ref CH2 math trigger timebase background ras ter cursors user selectable CH1 CH2 CH1 and CH2 user selectable 1 to 6 user selectable DI 770 25 10 Hz to 2 MHz DI 770 100 10 Hz to 10 MHz 2000 counts 0 2 10 counts 0 3 10 counts 10 to 1 MHz 0 7 20 counts 1 MHz to 5 MHz 2 5 20 counts 1 MHz to 5 MHz low frequency roll of frequency is 10 Hz True RMS Peak Peak Mean Max Min dBm Power Crest Frequency Duty cycle Moment value CH1 CH2 CH1 CH2 CH1 CH2 CH1 CH2 CH2 CH1 CH1 CH2 gt the Hi lt then Lo gt lt COMP lt gt HI LO MAX MIN LOG CH1 CH2 LOG CH2
33. values and switch off autoranging for the channels After setting the sweep parameters the sweep function can be switched on using the on off button During the sweep the frequency readout in the display will follow the output frequency Note When the sweep function is used to determine frequency response characteristics be certain to set the signal shape to Sine Generating a previous measured signal from a file It is possible to generate previously measured signals with the function generator provided of course that the ampli tude and frequency of the signal are within the specs of the generator Measuring and storing a signal The function generator has two possibilities to generate previous measured signals It can either use the DDS mode or it can use a linear mode In the DDS mode a waveform of 1024 points is used to generate the signal Due to the DDS technique very accurate output signal frequencies can be obtained In linear mode a waveform of 64K points is used The sample clock of the generator can be set to a number of set tings in order to obtain different output frequencies The number of settings is limited When a stored waveform is used that is smaller than 64K points the remaining points are filled with a O volt value A signal that is measured stored and later generated has to meet certain points in order to be usable e The signal has to be measured in channel 1 of the scope e For DDS mode the record le
34. 00924 00 09 101028 a oll Co PARA ren te eater Cn ern tere ten ntr EA enter wetter ne Tene ERTE meee ter 65 ETSII W TACO na Sa 65 Rertorauo me ASUMEN ici 66 Start and stop Measures O IO wel naa neh tabs ds hae 66 Sinole me AS UTS CIS tia 66 PRN CA OM Sc ects O A A iauesanwsea slaves evens 66 Measurino mami Y AVES ridad 66 Measure the Total Harmonic Distortion of a signal cocccccnnnnnnnnnnnnnnnnnnnnnnnnononananannncnnnnnnnnnnnos 67 Pertormins cursor measurements dd aeons sanedens eunashacoxanucorawsonaeuscnseds 67 Settuno Up the cursor Measurements ii a tdi 67 10 Phe Function Generator ciccssiisicccasvecewscsstasccsesanncaxcesccevessesscedsscsiecssusdesscdivanssddaacesdedseaseecsnsuetesssaccessee 69 Pringiple OF the Mune tiONsg CMeLalONn a iaa 69 Stuctute orte TUMCHON 0 Add d da 69 Controle Me HNCHOn CEnerator atraco E ii 70 n gt F240 28 Rcd 9621 0 coger cd 70 PEQUE ii aa 70 A A E E naeadnseeas 70 AMP il a a a a 71 DECO Corn a E seaeta une cns aemeensomeeuen need 71 NUMneacalmMpue sree N 71 Pre ot uea a a a a a a gene Tone tet eee eA 72 TO de ON 73 A LO 73 e dO BG OVS E A O 73 Generating a previous measured signal from a file ooonnnnnnnnnnnnnnnnncnnnnnnnnnnnnnnnnnnnnnnnnnnnonnnonnnnnnnnnnnnnos 74 Measuring and toria a Sinaloa ii dios 74 Setune the TUNCHON Sentada pia 74 Table of Contents Vill DI 770 and WINDAQ Scope Manual 1 Introduction Many technicians investigate electrical signals Though the
35. 1 channel 2 reference signal 1 reference signal 2 math signal trigger symbol timebase background grid and cursors can be set to your own preferences Press the Display colors button on the Common page and a dialog will appear in which the settings can be made Setting the application language By selecting the language selection pull down on the Common page you can select an other language to be used in the application The program will instantly switch to the selected language Also a help file in the selected language will be opened when the Help function is activated Setting the location of files By pressing the Directories button on the Common page it is possible to set the directories for the files the program works with A popup menu will appear From this menu you can select a directory which you wish to change After selecting a directory an input dialog appears in which you can enter the name for directory Default text on the printer output It is possible to add three lines of text to the application These lines of text will be placed on every printout They are placed on the upper left corner of the printout Enter here e g the company address employee name telephone num ber etc To enter the text click the button Default text on the Common page and an input dialog will appear The three lines of text can be entered here To switch between the three lines use the lt Tab gt key or click with the mouse in the reque
36. 10 and 90 values are calculated Now the 10 and 90 points are searched left and right of the zero crossing point By using the number of samples between the 10 and 90 points the rise time is calculated Rise time right the rise time at the position of the right cursor is determined Sample time left using the left cursor position the time on which the selected sample is taken will be displayed Sample time right using the right cursor position the time on which the selected sample is taken will be displayed Sample time difference the difference between the right and the left cursor sample time is determined Cursor frequency using the number of samples between the left and the right cursor the frequency is calculated The calculation is done using the following formula number of samples between cursors total number of samples sample frequency To determine a correct frequency always select one period or multiply the frequency by the num ber of selected periods for greater precision Voltage Voltage left the voltage of the left cursor will be displayed Voltage right the voltage of the right cursor will be displayed Voltage difference the difference between the voltage of the left and the voltage of the right cursor is calculated Selecting the min and max of the signal the top top value is calculated Slew rate Slew rate left the slew rate of the signal at the position of the left cursor is determined The slew rate
37. CAUOMS a 5 CPSC MOS COP iio 5 VOITEET rererere aaa aaa aaae 6 Transe MU RECOLJCT as ic 6 SPECT ANII YZE A A O O A 6 Arbia Wave Oli GEnCrator pdas a e n A cd c spnds 7 Acaso al lleida 7 Arbitrary Waveform Generator independent from acquisition system sscssseeessseeeseeeeeeeeeeees 7 MES O A NARE E eae ain aie ena E tea eae aca eae ame E E 8 Power REQUIEM A A a ee Suede 8 PING SIG scroll 8 VOC On CUS ra sos cece ance tenance R ea ce ee eee 8 SYSTEM REQUIEM A A rai n 9 Cperatine ENVIOS SAS 9 Storase En VIO id 9 Certitications and Complances dida 9 PP O 9 3 Msalato A a ia 11 REQUIEM die ataud 11 Dive Tata es DO Lo 11 mstalline Win Daq Scope OWN A A 12 d Connec Hons asscscandniiad in a liada 13 AREA A O A a RE 13 EXPO WE a e dea el ed 13 3 WimDad SCOP SOMWAFE Li iniciaba 15 Suc CUT Or Me Proa A aca 19 AI A akdcncdubcmncdonsatatoaasinne kucbosthaceaostuataciaicee 19 FCO AAA O O O T 19 Controlline the ISTMO a 19 Keys that Can De used sedna a aia 20 Controlling with the Mouse ES O eee eae eee 21 POSTAS CU trol 21 Instrument taskbar always ON OD oil 21 Seti pla COS ear cdo 22 Settins the application LANGUAGE A a E 22 Settino NE location OL TES traidores cias 22 Detaulttexcon the ITV OU CIE cs oe eatearh ac chacn E thew ak eae E ae ena 22 PI E 22 Table of Contents V DI 770 and WINDAQ Scope Manual Sette the date and me Ulea iii 22 DC ATC I NOWA ea N N 22 Manually adjusting of calibration factors oooooo
38. CH1 Volt Amp C F Watt Meter Colomd Hertz Bar user defined CH1 CH2 user defined value No sound 100Hz 200Hz 500Hz 1kHz 2kHz and 10 kHz direct on paper on disk and on network used defined value CH1 CH2 CH1 and CH2 1 to 131060 0 01 sec to 500 sec 21 min to 750 days scroll mode or scan mode see oscilloscope time of start time of measuring time difference CH1 CH2 CH1 and CH2 single shot continuous max mode standard mode 200mVolt 500mVolt 1V 2V 5V 10V 20V 40V 80 Volt full scale 0 25 to 4 magnifying Specifications 6 DI 770 and WINDAQ Scope Manual Input coupling Frequency axis Octave range Frequency range Record length Windows functions Averaging Cursor readout Total Harmonic Distortion AC DC Logarithmic linear octaves or third octave 22 1Hz to 22 6 kHz DI 770 100 0 01 Hz to 50 MHz DI 770 25 0 01 Hz to 12 5 MHz 32768 to 32 frequency components rectangular Hanning Hamming Bartlett Blackman Parzen 1 to 256 measurements see oscilloscope 1 to 100 spectrums Arbitrary Waveform Generator Signal sources Sweep Frequency Amplitude Symmetry DC offset Presets Record length Acquisition System Resolution Bandwidth 3dB Sample rate Sample source Number of input channels Input sensitivity Input protection Input impedance Input coupling Input accuracy AC coupling cut off frequency 3dB Memor
39. Enter the Measure menu and select the Start measuring item When the measurement is started all controls except the Stop controls are disabled Stop measuring When the predefined number of samples is reached the data logger will stop measuring It is also possible to stop the data logger manually e g when the event to measure is measured or the instrument settings are wrong coupling sensitivity etc This can be done in three ways e Clicking the Stop button EN e Pressing the lt S gt key e Enter the Measure menu and select the Stop measuring item When the measurement is stopped all controls are enabled again Scroll mode While measuring the data logger displays the measured signal on a 1 1 base meaning that for each sample 1 display pixel is used When the number of measured samples is larger than the available number of pixels in the display the record view offset has to be changed in such a way that the latest samples will be visible There are two ways to do this Scan mode When the display is full the record view offset will change a full screen so the new samples will start filling the display from the left hand side of the display again Roll mode When the display is full the record view offset will change with one sample making space for one new sample Each new sample causes a change in the record view offset Roll mode looks nicer than Scan mode but is also slower so the data logger will sooner miss sam
40. TO JV V3 V3 Vs Ve V7 Vo Vo PR og y l where V is the RMS amplitude of the base frequency of the input signal V V are the RMS amplitudes of each higher harmonic To measure the THD enter the Measure menu and select the Total Harmonic Distortion item or by pressing the THD button The software will determine the base frequency of the signal by assuming that the spectral component with the largest amplitude is the base frequency Then the amplitudes of all higher harmonics up to 100 in the measured record are determined and the THD is determined In the THD output window the base frequency of the signal is given the harmonic distortion in dB is given and a table with the amplitudes of all used harmonics is given This is done for all active channels The number of harmonics that is used for the calculation depends on the base frequency If the base frequency is low more harmonics are found than when the base frequency is high The calculation routine will use up to 100 harmonics or up to a user defined number This user defined number can be set by entering the Measure menu and selecting the item Max number of harmonics to use A new menu will pop up with the possible numbers Performing cursor measurements Like in the oscilloscope the spectrum analyzer has a set of cursors to perform measurements on the displayed signals The cursors in the spectrum analyzer work almost like in the oscilloscope so only the d
41. The only difference is that in the data logger no auto ranging for the input sensitivity is available For information on setting up a channel see chapter 2 the oscilloscope Setting up the time axis The time base in the data logger is almost the same as in the oscilloscope However the data logger has no pre trigger setting Therefor only the items that differ from the oscilloscope time base settings are discussed here Setting up the sample speed The data logger measures a number of samples with a certain time between two samples This results in a total mea sure time of number of samples x time between two samples To setup the timing characteristics of the data logger measurement open the data logger measurement speed dialog The dialog can be opened by activating the choice Sampling speed from the Time base menu In the upper part of the dialog a selection has to be made how the timing characteristics of the data logger measure ment have to be set There are three possible ways The Data Logger 56 DI 770 and WINDAQ Scope Manual e Enter the number of samples and the time between to measurements The total measuring time is determined by the dialog e Enter the number of samples and the total measuring time The time between two samples is determined by the dialog e Enter the time between two samples and the total measuring time The number of samples is determined by the dialog When a selection is made th
42. an be changed by using a menu or by dragging the vertical axes To adjust the offset by means of a menu enter the Chl menu and select the choice Software offset A dialog box appears in which the off set can be entered The value is in Volts The easiest way of adjusting the offset is by dragging the axis This is done by pressing the left mouse button within the vertical axis but not over the inverted area on the top and bottom of the axes and moving the mouse up or down while keeping the mouse button pressed Magnifying or reducing the vertical axis The measured values can be magnified or reduced by the software by the Software gain By doing this the vertical axes can be made larger or smaller This can be used to display two signals of different sizes on the screen to be compared more easily For example Ch1 is measuring a 5 Volt signal Ch2 is measuring a 4 volt signal Set the gain of Ch1 to 0 8 and the gain of Ch2 to 1 Both signals are displayed with the same size Another application is to display two signals in a split screen mode By setting the gain of the channels to 0 5 and the offset of Chl 2 divs up and the offset of Ch2 2 divs down the channels are displayed separately The software gain can be changed by using a menu or by dragging the vertical axes To adjust the software gain through the menu enter the Chl menu and select the choice Software gain A dialog box appears in which the gain can be entered The val
43. ange shape click the left mouse button and drag the side of the slider to the position you want Simultaneously the record view gain will be adjusted and the signal in the display changes accordingly Note The minimum slider width is 10 display pixels and the scroll bar width is dependent of the window size so the maximum gain is limited to scroll bar width in pixels 10 With a large window the record view gain can be set to a larger value than with a small window Size The Oscilloscope 37 DI 770 and WINDAQ Scope Manual To change the record view offset place the mouse pointer anywhere on the slider except on the left hand side or the right hand side The mouse pointer will not change shape Press the left mouse button and drag the slider to the posi tion you want The record view offset will be adjusted and the signal in the display changes accordingly When the small buttons are clicked the record view offset is increased or decreased by sample When the mouse is clicked within the scroll bar but outside the slider the record view offset is increased or decreased by 5 samples depending on which side of the scroll bar is clicked When the mouse button is kept pressed an auto repeat function is activated Triggering To be able to examine a signal the moment of displaying the signal has to be adjustable Therefore an oscilloscope is equipped with a triggering system This functions as follows tiring level arming level
44. ared to the high value and the low value If the value is higher than the high value HI is displayed If the value is lower than the low value LO is displayed If the value is lower than or equal to the high value and higher than or equal to the low value PASS is displayed lt gt HI LO The value is compared to the high value and the low value If the measured value is higher than the high value PASS is displayed If the value is lower than the low value PASS is displayed If the value is lower than or equal to the high value and higher than or equal to the low value FAIL is displayed The Voltmeter 50 DI 770 and WINDAQ Scope Manual DISPLAY gt than HI lt than LO gt lt COMP lt gt HILO PASS HI HI PASS PASS FAIL measured value LO The maximum measured value ever is displayed The minimum measured value ever is displayed LOG 1 2 The result of the calculation measured valueCH 1 20 x log measured valueCH2 1s displayed LOG 2 1 The result of the calculation 20x lo measured valueCH2 measured valueCH1 is displayed Change the units of measure Normally every type of measurement has its own unit The voltmeter allows you to change this unit for each display separately There are twelve predefined values and a user defined value The selection can be made with the Units of measure pulldown The unit which is selected is displayed in the display To select a user defined unit
45. asured and calculated values 16 methods are available See displaying the measured value Four of those methods are comparison measurements gt than HI lt than LO gt lt COMP lt gt LO HI These measurements require a high and a low value By entering a value in the Set high value or Set low value edit boxes the high and low levels can be set Note For easy entering of low and high values the software does not check whether the high value is larger than the low value So it is possible to enter a low value which is larger than the high value Measurements using these values will give useless results Setting the reference impedance The dBm and power measurements require a reference resistance The value of the resistance can be set using the Set impedance value edit box The value has to be entered in Ohm The default value is 600 Setting the number of digits after the decimal separator With every calculation done on a measurement a default number of digits after the separator is set auto setting This number corresponds with the significant number of figures determined by the hardware The number of digits after the separator can be changed using the Number precision selector Note The displays have a maximum number of 6 digits When the value in the display is that large that digits before the decimal separator can t be displayed an arrow pointing to the left is displayed left from the first digit The dis played digit
46. ation with the spectrum analyzer be used for creating frequency response characteristics of components or circuits And the function generator provides for a number of user definable preset positions Principle of the function generator The function generator uses the DDS technique DDS stands for Direct Digital Synthesis a technique that uses digi tal data processing blocks to generate a frequency tunable with a fixed frequency precision clock DDS allows to generate low distortion signals with very accurate frequency adjustment in a fully digital way Structure of the function generator The function generator is built out of a number of functional blocks At the top a display is located which shows the signal shape and the other settings of the function generator Left of the display there are the signal shape selector buttons Below the display are the controls for the frequency symmetry amplitude and offset of the signal At the right of the display are a key pad for numerical input and a key pad for the presets This part of the screen can be hidden using the small button at the right upper corner of the display of the function generator The function generator will become smaller and taking up less space on the computer display Pressing the button again will expand the window again The same can be obtained by pressing keys lt Shift lt gt and lt Shift gt gt The Function Generator 69 DI 770 and WINDAQ Scope Manual
47. bits determines the number of quantifying steps accord ing the formula number of quantifying steps 2 Umber of bits A 2 bits ADC has 4 quantifying steps With an input range of 10 Volt this ADC can divide the input range in 4 parts of each 2 5 Volt By increasing the number of bits the resolution increases the number of quantifying steps increases and the sub divi sions get smaller The probes The DI 770 is shipped with two probes These are 1x 10x selectable passive probes This means that the input signal is passed through directly or 10 times attenuated The x10 attenuation is achieved by means of an attenuation network This attenuation network has to be adjusted to the oscilloscope input circuitry to guarantee frequency independency This is called the low frequency compensation Each time a probe is used on an other channel or an other oscilloscope the probe must be adjusted Therefore the probe is equipped with a setscrew with which the parallel capacity of the attenuation network can be altered To adjust the probe switch the probe to the x10 and attach the probe to a 1 kHz square wave signal Then adjust the probe for a square front corner on the square wave displayed See also the following illustration Introduction 3 DI 770 and WINDAQ Scope Manual correct under compensated over compensated Introduction 4 DI 770 and WINDAQ Scope Manual 2 Specifications Oscilloscope Display channels Dis
48. caption bar Switching off cursors To switch off cursors enter the Cursors menu and select the No cursors item The Cursors menu can be found in the main menu or can be called by clicking the right mouse button in the signal display When the cursors are switched off the cursor readout window disappear as well The cursors can also be switched off by clicking the close button gt in the cursor readout window The Oscilloscope 44 DI 770 and WINDAQ Scope Manual 7 The Voltmeter If from the input signals only the size is important and not the time information or frequency components a voltmeter is a Suitable instrument to measure with The software is equipped with a two channel digital voltmeter The voltmeter functions as follows e A measurement is performed minimal 200 samples e The measured data is processed e g for calculating the RMS value or the mean value Eleven different opera tions are available e The calculated values are displayed e g add CH1 and CH2 and display on channel one Sixteen different display methods are available For each channel the voltmeter has up to three displays to present the measured and calculated values The value dis played in a display is fully configurable Also for each display a bar graph is available to give a quick overview of the signal size in relation to the input range Voltmeter File Measure Acquistion Settings Help 00 Estes Channel 2 sensitivity 2
49. ce I of the data logger The values of display 1 of channel 2 will be placed in channel 2 of the data logger The values of display 2 of channel 2 will be placed in Reference 2 of the data logger Setting the Waveform read method When a waveform is written to disk all four channels Ch1 Ch2 Reference 1 and Reference 2 are written to disk There are two methods to read waveforms from disk Read all signals in file With this method all signals that were active when the waveform was written are read If e g Chl and Reference 2 were active when the waveforms were saved Chl and Reference 2 are read the data in Ch2 and Reference 1 will remain unchanged Chl and Reference 2 will be switched on and Ch2 and Reference 1 will be switched off Only read current displayed signals Software 25 DI 770 and WINDAQ Scope Manual With this method only the currently active channels are read from the waveform file The other channels will remain unchanged and they will remain switched off To select the proper waveform read method enter the File menu select the Waveform read method item and select the correct method When closing the application the selected method is saved in the application settings file This file is always read when starting the application Comparing signals using the reference channels To be able to compare live signals to other signals the oscilloscope the data logger and the spectrum analyzer have two reference channel
50. d the size is displayed at the screen The screen is filled with all samples Between two adjacent samples on the screen a line is drawn The speed at which the samples are taken is adjustable Cursors are available to perform voltage time or frequency measurements on the displayed signal File Measure Chi AT Lime base Trigger eal Math til aida Help 001 S ile r O eee 20 U0kK3 Sec 0 00 fr i JE 400 ES ES a Peete ee be De 500 EEE ES o do ed 1 000 5 00m 10 00m 15 00m J 25 00m pe 0 The Oscilloscope 29 DI 770 and WINDAQ Scope Manual Aliasing A disadvantage of digital sampling oscilloscopes is the fact that aliasing can occur Aliasing occurs when a too low and therefor wrong sampling frequency is used The next illustration shows how aliasing occurs Yn 0 6 ms lampie me p Tapparent 4 ms P The input signal is a triangular signal with a frequency of 1 25 kHz upper most in the illustration The signal is sam pled at a frequency of 1 kHz The dotted signal is the result of the reconstruction From that triangular signal the peri odical time is 4 ms which corresponds with an apparent frequency alias of 250 Hz 1 25 kHz 1 kHz To avoid aliasing the sample frequency must be greater than 2 times the maximum frequency of the input signal If you have any doubts about the displayed signal you can set the timebase of the oscilloscope one step faster or
51. displays the correct value Peak peak The peak peak value of the input signal is determined The peak peak value of a DC voltage is zero The peak peak value of a true sine wave with a RMS value of 1 volt is 2 828 volt The mean value of the input signal is determined The mean value of a varying voltage corre sponds with the value of a DC voltage across the same load The mean value of a 1 volt DC voltage is 1 volt The mean value of a true sine wave AC voltage is 0 The maximum of the input signal is determined The maximum value of a 1 volt DC voltage is 1 volt The maximum value of a volt AC sine wave voltage is 1 414 volt This is determined from the 200 samples The minimum of the input signal is determined The minimum value of a 1 volt DC voltage is 1 volt The minimum value of a 1 volt AC sine wave is 1 414 volt Determined from the 200 samples The value of the input signal is converted to dB This is done using the formula 1000 x les dBm 10x lop He _ reference resistance value is the RMS value of the input signal The reference resistance can be set using the edit box set impedance value The value of the input signal is converted to a power using the formula 2 POWER vdue __ reference r esistance value is the RMS value of the input signal The reference resistance can be set using the edit box Set impedance value The value of the input signal is converted to a crest factor using the form
52. e It is recommended that you accept the default C WinDaq770 When prompted to Select a Program Manager Group specify a destination or group window in the Start Menu for your software icons It is recommended that you accept the default Installation 1s complete you will now see a Successful Installation box click on OK to exit WINDAQ Installa tion To run WINDAQ Scope software go to the appropriate program group specified above default is Start gt Pro grams gt WINDAO Scope and click on WinDaq Scope Hardware Installation 12 DI 770 and WINDAQ Scope Manual 4 Connections BDATAQ A cE u INSTRUMENTS Seeeeeeeeesae IO USB Peras sn a a A oy E dba rom O Auxiliary O O Aux Power In k Extension connector To connect to the DI 770 a 25 pin female Sub D connector is available containing the following signals 1 Ground 14 Ground 2 not connected 15 Ground 3 External power in 5V DC 500 mA 16 Ground 4 Ground 17 Ground 5 5 Vout 10 mA max 18 Ground 6 External sampling clock in 19 Ground 7 Ground 20 not connected 8 External trigger in TTL 21 not connected 9 Data OK out TTL 22 Ground 10 Ground 23 PCSDA 11 Trigger out TTL 24 PCSCL 12 Square wave generator out TTL 25 Ground 13 External sampling clock out External power The DI 770 is powered through the USB If the USB cannot deliver enough power an external power cable to the keyboard connector can be connected
53. e input Remove the last entered character HAHOOBRE End the input and apply it Terminate the input Esc Presets The function generator has 8 preset positions to store signal settings Presets sfaf7fe With a single press on a button a signal with a specified shape amplitude offset frequency and symmetry can be generated The presets are stored together with the application settings and are restored each time the application is started Storing When a signal is set that is not yet stored in a preset position and there is a free preset position available the store button is enabled By pressing the button the signal settings are stored in the free preset position with the lowest number The Function Generator 12 DI 770 and WINDAQ Scope Manual Selecting When presets are stored the corresponding preset buttons are enabled By hovering the mouse pointer over one of the buttons the settings of that preset position are displayed By pressing a preset button the function generator is set according to the stored settings The button of the preset will be lowered indicating that preset is active When during use of the function generator a setting is changed and the new setting corresponds with a stored preset the corresponding button of that preset will be lowered When a preset is selected and the setting of the function gen erator is changed to a setting that does not correspond with the preset the corres
54. e mode is reset each time when the setting of the instrument changes sensitivity offset record length etc when the window size changes and when the pre defined reset number is reached To set the reset number enter the Envelope menu which can be found in the Measure menu or by clicking the right mouse button on the Envelope mode button ai Select the item Reset envelope after and a menu with the possible option pops up When the choice 32 measurements is selected envelope mode will be reset after 32 measurements When the choice infinite measurements is selected envelope mode will not be reset automatically only by changes in the instrument settings or by a window size change Envelope mode can be switched on by clicking the envelope button by pressing the lt E gt key or be selecting the item Envelope mode from the Measure menu When envelope mode is switched on the Envelope button stays down Envelope mode is switched off by pressing the button again pressing the lt E gt key again or by selecting the Envelope mode menu item again Note Envelope mode is only a display function The envelope signal is not stored to disk or printed in a hardcopy operation Averaging When a noisy signal is measured the influence of the noise can be eliminated by averaging several measurements The noise component s will disappear and the actual signal remains Averaging can be switched on by selecting the item Perform averaging of from the Meas
55. e selected items can be entered in the input boxes in the lower part of the dialog Under the input boxes the determined value of the third parameter is displayed When an invalid combination is made the text in the input box that causes the invalid combination turns into red When this is ignored the value is clipped to the nearest valid value When the parameters are set properly the OK button can be clicked to apply the values and return to the data logger Note The timing in the hardware is generated by a crystal oscillator and two programmable integer dividers This system can t generate all frequencies but comes close When the OK button is clicked the software will determine the division values for both dividers in such a way that the generated frequency approaches the requested frequency as close as possible A lot of divider combinations have to be checked for that While determining the correct division factors an hour glass is displayed Setting the record length The data logger takes a number of samples to display the input signal This number of samples is called the Record length To change the record length three ways are available using the record length menu using the sample speed dialog or by means of function keys To change the record length using the menu enter the Time base menu and select the Record length item Another menu will pop up containing the available record lengths and an item for a user defined record len
56. e will be free from defects in materials and workmanship under normal use and service for a period of one year from the date of shipment DATAQ Instruments obligations under this warranty shall not arise until the defective material is shipped freight prepaid to DATAQ Instruments The only responsibility of DATAQ Instruments under this warranty is to repair or replace at its discretion and on a free of charge basis the defective material This warranty does not extend to products that have been repaired or altered by persons other than DATAQ Instru ments employees or products that have been subjected to misuse neglect improper installation or accident DATAQ Instruments shall have no liability for incidental or consequential damages of any kind arising out of the sale installation or use of its products Service Policy 1 All products returned to DATAQ Instruments for service regardless of warranty status must be on a freight pre paid basis 2 For in warranty repairs DATAQ Instruments will return repaired items to the buyer freight prepaid Out of war ranty repairs will be returned with freight prepaid and added to the service invoice DI 770 and WINDAQ Scope Manual Table of Contents Warranty and Service Pollera ias iii Py Introductorio aiii 1 ATLENDION art ios l A O l SPANS T ds 2 BPA AS NN oia E 2 DIA co aonadeneeane mow nesta nentchanee date nave aeemcn stone tieaeusaecaenns 3 WG PV OWES aci icitis 3 De SPCC
57. ecific part of the signal Erase the signal screen The time axis can display sample times and real time and date Set this by opening the Settings menu The right mouse buttons allows the complete time base to be set up Drag this end of the slider and change the horizontal magnification Press the right mouse button and setup the time base Drag the slider and adjust the horizontal position of the signal Press the right mouse button and setup the time base The hint bar displays explanation of the objects the mouse is placed on Drag the vertical axis and adjust the vertical position of the signal Press the right mouse button and setup chan nel 1 Software 17 DI 770 and WINDAQ Scope Manual Da 4 a a O O File Measure Chi Che Frequency axis Cursors References Settings Help A el Auto A A ae omy 8 reo E ot 250M 5 00h T50 10 00m 12 50M Ey 1 Press this button to place a comment label in the display 2 Press the Window button to select a window function for the FFT 3 Stop the continuous measurements 4 Make a hard copy of the current signal 5 Measure the Total Harmonic Distortion 6 Double click here to switch channel 2 on 7 Press the right mouse button to setup the frequency axis 8 Dragging this slider adjusts the horizontal position of the signal Pressing the right mouse button allows setup of the frequency axis 9 Drag this end of the slider or the oth
58. ements A A ws Ke A Seen ld A herd ence 42 Selecta THe ACTIVE CMAN nte a 44 Showing or hiding the Cursor readout oooooocoocnncncnnnnnononononononnnnnnnnnnonnnnnnnnnnnnnncnnnnnnonnnannnnnncnnnnnnnnos 44 Sa A oacaaeyacaratoccteae haneasaedenatencciaretaen 44 7e The OIM E RA ues veusesesesueasncenenswacsacesassaoes aS 45 The measures y stem ofthe Voltmeter oerein aa ios 45 Setning MerrEQUeN CY FAN OC as 46 DAS o AA O Toren rrr nt SaenT nny tnt frre anr ae 46 Ye MAHAL UR NO es IO 46 DC LU EME IN DUE PAIN E a A Sos 46 Sele Ne Input COU PMNS ri til 47 Se Fume a DCE Mardy ake ole nicotina 47 Contursi SPA Ss vues xe eS a ae a 48 Switchine displays on AM OlT A A AAA 48 Switchins barsraphs onr and OH a a A ao e a A laden eds 48 Processine the measured Vale id llei 49 Displayino the calculated Valle cereales inocencia 50 Chane thennts OLMO dida 51 Change The units per measurement units did ll 51 Rekuvye measure MoS ere A 51 Comparison measure aio coS 92 Seta he TELETENCE 1M PE GANC Ss ninn a sassasbneed teas eeeeneumntaeaneds 52 Setting the number of digits after the decimal separator cccccooonooocnnncnnnnnnnnnnonononanononnnnnnnonnnononos 52 SO E PU Ue En a E E EA bataoconses 52 Resetting the minimum and maximum values oooooonnnnnnnnnncnnnononnnnnnnnnnnnnnnnnnnnnnnnnnnncnnnnnnnnnnnnannnoss 53 Bertone Measurements adari iia iii 53 Start and Stop MES ts ias 33 GV CRAIN O a E a a cane rac lady teu aaa tah scc cat eaaaana lan aa
59. er end to adjust the horizontal magnification Press the right mouse button to setup the frequency axis 10 Drag this label of the axis and adjust the vertical magnification Press the right mouse button to setup channel 1 11 Drag the axis and adjust the vertical position of channel 1 Press the right mouse button to setup channel 1 12 This led indicates whether the input signal is clipped creates higher harmonics or not Software 18 DI 770 and WINDAQ Scope Manual Structure of the program The program is divided into 4 integrated measurement instruments which are available on the instrument taskbar TP208 3500 version 1 0 0 e An oscilloscope e A true RMS voltmeter e A data logger e A spectrum analyzer If an instrument is not active instrument button state is up the instrument can be made active by pressing the left mouse button over the instrument button If the instrument is active instrument button state 1s down and you press the left mouse button over the instrument button the instrument will be made inactive and it will hide itself If you have 2 or more instruments active one instrument can be on top of the other To make the inactive instrument active you can move the currently active window away from the inactive window so you can select it However there is a faster way assuming the taskbar is visible press the right mouse button over the instrument button The other four buttons represent the fo
60. external power supply but is powered by the computer through the USB The USB can deliver only a limited amount of power In case the USB can not supply enough power an extra cable is supplied which can be connected to the DI 770 and between the computer and the keyboard cable In that case the DI 770 will be powered by the keyboard connection Note The outside of the external power connector is connected to 5 Volt In order to avoid shortage first connect the cable to the DI 770 and then to the keyboard connector Requirements To use the Windows software you need e AnIBM compatible PC AT with 386 25 processor or higher mathematic coprocessor recommended e Microsoft Windows 3 1 or higher e 32 MB RAM e 4 MB free hard disk space e A mouse or other pointing device e ACD ROM drive Optional A sound card with wave file playback and or general midi Driver Installation 1 With your computer powered Windows running and all other applications closed plug the appropriate end of the supplied USB communications cable into the USB port labeled USB on the rear panel of the instrument Connect the other end of this cable to one of your computer s USB ports The addition of this new piece of hard ware will be sensed by Windows and the Found New Hardware Wizard will automatically be launched anticipating the installation of a device driver for the new hardware 2 Insert The WINDAQ Resource CD ROM into your CD ROM drive
61. f the input signal s The sample frequency can be set in two ways using the menu of by means of special function keys To change the sample frequency using the menu enter the Time base menu and select the Sample frequency item A new menu will appear with all possible sample frequency settings Together with the sample frequency the maximum total measure time with the current record length and a pre trigger value of 0 is given The Time base menu can also be entered by pressing the right mouse button over one of the time base controls or read outs The last item in the menu is a user defined setting Activating this item will bring up a dialog box in which a self defined sample frequency within the instrument hardware limitations can be entered Due to the way the sample fre quency is generated in the hardware not all frequencies can be generated If an invalid sample frequency is entered the closest valid sample frequency will be generated The following keys can be used to change the sample frequency Set the sample frequency one step slower lt F4 gt Set the sample frequency one step faster Note Because the record length the number of post samples and the record viewing gain are free settable it is very difficult to set the time base in a certain number of sec div Therefor the sampling frequency is set Setting the record length The oscilloscope takes a number of samples to display the input signal This number of samples is
62. file with the extension DAT containing the waveform data of both channels and both references a file with the extension GEG containing the instrument settings a file with the extension REF containing the reference channels settings The files containing the settings are ASCH files with a windows INI file structure The DAT file can be either binary or in ASCII When the file already exists a warning will be given When the disk is full the file will not be written and an error will be put on the screen Setting the data file type The waveform data can be stored in a binary and in an ASCII format Software 24 DI 770 and WINDAQ Scope Manual The binary format is built of records of 8 bytes large The first two bytes are for channel 1 bytes 3 and 4 are for chan nel 2 bytes 5 and 6 are for reference 1 and bytes 7 and 8 are for reference 2 The two bytes for each channel form a 16 bits value where O represents sensitivity and 65535 represents sensitivity The ASCII format exists of one line of information for each sample in the record Each line exists of the sample number related to the trigger point sample number 0 the sample time related to the trigger point t 0 the voltage value for channel 1 the voltage value for channel 2 the voltage value for reference 1 the voltage value for reference 2 The items are separated by commas The ASCII files can simply be imported in other applications like e g spread shee
63. ger is forced This is used to see an unknown signal This feature can be unwanted in the auto disk function therefor a Time out infinite check mark is available to set the time out to infinite Then the oscilloscope will keep waiting for the input signal to meet the trigger conditions When all is set press the Start button to start the auto disk measurements The Cancel button will change to a Stop button and measuring takes place The auto disk measurements stop when the Stop button is pressed or when the disk is full Note In the root of a disk only 128 files can be stored A RAM drive has a user definable number of entries default 64 and can store no more files than there are entries available The auto disk function will stop with a disk full error when this number of files are written However DOS or Windows might still report a certain amount of free space on the disk To be able to store more files create a directory on the disk and store the files in that directory A directory can contain many more files Note The auto disk function can store only 999 files due to the three characters that are used for creating the file serial number Auto setup When an unknown signal is connected to the oscilloscope the easiest way to setup the oscilloscope is by using the Auto setup function The Auto setup function is activated by selecting the item Auto setup from the Measure menu or by pressing the Auto setup button E This function
64. gth Selecting this item will bring up a dialog box in which a self defined record length within the instrument hardware limits can be entered The Time base menu can also be entered by pressing the right mouse button over one of the time base con trols or read outs For changing the record length the following function keys are available Select a shorter record length Select a longer record length For the third way to change the record length see setting up the sampling speed Setting the horizontal axis type The data logger can measure for a very long time In that case it can be useful to have real time and date values along the time axis instead of the number of seconds since the starting moment This can be selected by opening the Settings menu and select the Horizontal axis type item Now you can select between Date Time and Sample times Perform measurements Before measuring with the data logger the channels and the time base have to be set up completely The channels do not have auto ranging so the sensitivity has to be set manually Since the data logger usually mea sures slow signals the input coupling should be set to DC otherwise the input capacitor will block the signal Start measuring When all settings are made the data logger can be started This can be done in three ways The Data Logger 57 DI 770 and WINDAQ Scope Manual e Clicking the Play button e Pressing the lt S gt key e
65. h the current measured value and divides it by three In this way very small changes do not show up which results in a more stable values To switch averaging on or off enter the Settings menu and select the Mean values option The check mark in front of the menu item indicates whether averaging is on or off Fast measuring By selecting the option Fast measuring from the Settings menu fast measuring is enabled or disabled Before the fast measuring option can be enabled you have to set a frequency range other than scope or auto When enabling the fast measuring option the trigger timeout is set to zero the record length and post samples are set to 200 and the averaging is disabled One shot measurements A single measurement can be performed by pressing the oneshot button or by selecting the Perform single measure ment option from the measure menu Note One measurement consists of three successive measurements except if fast measuring is selected or mean val ues is disabled these take one measurement from which the measured values are averaged Between the measure ments the display is updated If the voltmeter has to perform an autoranging action or has to change the sample frequency during an oneshot measurements are taken until all changes to the range and the frequency have been done Then three measurements are taken with the final settings The Voltmeter 53 DI 770 and WINDAQ Scope Manual Continuous measuring can be
66. he spectrum analyzer determines how the start and stop frequency and the frequency step size are set The lowest visible The Function Generator 73 DI 770 and WINDAQ Scope Manual frequency in the spectrum analyzer sets the start frequency of the sweep The highest visible frequency in the spec trum analyzer sets the stop frequency of the sweep This is limited to the maximum range of the function generator The frequency step size is determined by the frequency range of the spectrum analyzer divided by the number of bins in the spectrum When a sweep is active and a setting in the spectrum analyzer is changed the sweep parameters will change accordingly At each step the frequency of the generator will be set to a value that falls exactly in one single bin therefor no cal culation errors occur and no window is required The setting Manual requires that all settings are set by the user The start and stop frequency can be set freely The fre quency axis of the spectrum analyzer will be set accordingly so only the range that is sweeped will be visible The frequency step size can be determined from the spectrum length With each step a frequency will be set that gen erates no calculation errors It s also possible to set the step size manually but that will probably do generate calcula tion errors in the FFT Hint For easy creating frequency response characteristics set the measure mode of the spectrum analyzer to Mea sure maximum
67. he comment label can be edited An input dialog with a text input box appears after activat ing Enter the text for the comment label in the input box Multiple lines can be entered and will appear in the com ment label as they appear in the text input box Comment shape With this item the shape of the comment label can be selected Three choices are available a rectangular shape a rectangular shape with rounded corners and an ellipse shape Draw arrow With this item the arrow can be switched on or off When the arrow is switched on a check mark is placed in front of the menu item Software 27 DI 770 and WINDAQ Scope Manual Arrow point shape The arrow point can have different shapes no point at all a square a circle a triangle and an arrow When no point is selected only a line from the comment label to the end point of the arrow is drawn When the arrow point is selected a triangle is drawn that is always pointing away from the comment label When Draw arrow is switched off this item is not available Comment colors With this choice the foreground color and the background color of the comment label and the arrow can be selected The foreground color is used for the line around the comment label for the text for the arrow and for the line around the arrow point The background color is used to fill the comment label and the arrow point Deleting a comment label To delete a comment label place the mouse cursor on the co
68. he currently displayed values are set as the calibration values to use Loading of a calibration file at start up will be disabled Cancel All changes including the applied are ignored and the calibration values which were used prior to pressing the adjust cal values button are restored Load values A file dialog is presented in which a file can be selected with calibration values which has to be loaded and displayed in the grid Save values A file dialog is presented in which a filename can be typed or selected to which the values cur rently displayed in the grid can be saved Apply Sets the current grid values as the calibration values to use A one shot is done so the result is displayed The apply is not permanent until the Continue button is pressed Restore factory calibration factors The DI 770 has a set of calibration factors in EEPROM which are read at power up of the software If the calibration factors are altered manually the original values can be restored by pressing the Restore factory cal button If loading a calibration file at startup is enabled this will be disabled by pressing the Restore factory cal button Loading a set of calibration values at start up When a specific set of calibration values is made it can be stored on disk To use this file of calibration values at power up place a check mark in the Use cal file check box at the Hardware page If no file name was selected yet a file open dialog will ap
69. he input signals the data logger can not be used together with the oscilloscope voltmeter or spectrum analyzer 17 Data logger Timebase Cursors O 1500 samples 500 00msec JU OU aam 100 00 100 00 UU UL i 15 9 97 8 52 20 00 16 9 97 6 53 26 00 18 9 97 6 54 36 00 The data logger measuring system Before measuring with the data logger the channels and the time base have to be set up completely When all settings input sensitivity coupling number of samples sample speed etc are made the data logger can be started All settings will be applied to the hardware and the hardware begins to measure The hardware will continue measuring until the predefined number of samples is measured or when the user interrupts the measurement Each measured sample will be stored in the board memory of the hardware The Data Logger 55 DI 770 and WINDAQ Scope Manual When the measurement is running the software will constantly monitor whether a new sample is measured If a new sample is measured it is obtained from the hardware acquisition memory and displayed on the display This will con tinue until the measurement is ready Note At certain sample speeds and or relatively slow computers it might occur that the software can t keep up with the hardware in other words the software misses samples the hardware has measured and stored
70. hot button press the lt O gt key or activate the Perform a single mea surement item from the Measure menu Continuous measuring can be started again by pressing the Play button the lt S gt key or the item Start continuous mea suring from the Measure menu The One shot button will be disabled again Perform Auto disk measurements The oscilloscope can store measurement data automatically on disk This is very useful when e g an interference glitch has to be measured Suppose that at unpredictable times a glitch occurs By using the auto disk measurements the oscilloscope will wait for the glitch to occur When the glitch occurs it is measured and the data is stored on disk The time and date of the measurement are stored as well To activate the auto disk function first set up the oscilloscope to the appropriate settings input sensitivity sample frequency record length etc Then enter the Measure menu and select the Auto disk item A special auto disk dialog will appear In this dialog a target disk a target directory and a name for the files can be selected For the file name only 5 characters can be entered three characters will be added by the software for a file serial number At the bottom of the dialog a bar graph is displaying the available disk space on the selected drive The trigger system of the oscilloscope has a time out function When the input signal does not meet the trigger condi tions within a certain time a trig
71. icking the right mouse button over one of the Chl or Ch2 controls and readouts In the tool bar for each channel a coupling button is found the coupling button for Ch1 at the left hand side of the screen for Ch2 at the right hand side of the screen The picture at the button indicates the state of the coupling setting The left button of the two buttons below is indicating AC coupling the right button is indicating DC coupling ME The current coupling state is displayed in the coupling button The Oscilloscope 32 DI 770 and WINDAQ Scope Manual The keys which can be used to change the signal coupling are sets the coupling of channel 1 to AC a sets the coupling of channel 1 to DC lt Shift A gt sets the coupling of channel 2 to AC lt Shift D gt sets the coupling of channel 2 to DC Setting the vertical position of a channel The vertical position of a channel on the screen is software adjustable When setting the vertical position of a channel the signal is adjusted graphically after all the samples have been taken This only affects the displaying of the signal If the input signal is clipped because it is larger than the selected input sensitivity range and the signal is adjusted the signal stays clipped The clipping will show very clearly on the screen The signal is cut off at the top or bottom This positioning method is mainly used to move signals which overlap each other on the screen The software positioning c
72. ifferences are discussed here Refer to chapter 2 the oscilloscope for more explanation on how to work with the cursors Setting up the cursor measurements With the cursors it is possible to measure the input signal s in several ways To set up the cursor measurements press the settings button at the cursor readout window the right most button at the left top of the window caption A menu appears containing the following options The menu can also be called by pressing the right mouse button over the table Time Frequency left the frequency at the position of the left cursor is determined Frequency right the frequency at the position of the right cursor is determined Frequency difference the frequency difference between the left and right cursor is determined Voltage Voltage left the voltage of the left cursor will be displayed Voltage right the voltage of the right cursor will be displayed The Spectrum Analyzer 67 DI 770 and WINDAQ Scope Manual Voltage difference the difference between the voltage of the left and the voltage of the right cursor is calcu lated Selecting the min and max of the signal the top top value is calculated Distortion The Total Harmonic Distortion of the input signal is determined Up to 100 harmonics are used for the calculation Automatic tracking cursors If this option is enabled the voltage levels of the cursors are automatically set to the voltage levels of the sample numbers which
73. ing FFT is that the frequency curve is folded back on itself amplitude Ed ales function The Spectrum Analyzer 60 DI 770 and WINDAQ Scope Manual The original signal is sampled at a sample time t The critical frequency Nyquist frequency is 1 2t Hz Windowing FFT treats the FFT block like it is one period of a periodic signal If the sampled signal is not periodic harmonic dis tortion can arise since the periodic waveform created by the FFT can have sharp discontinuities See also the fol lowing illustration These discontinuities are also called calculation errors This means that because of the calculation errors extra frequency components are generated around the true fre quency Because of this smearing the amplitude of the true frequency decreases since the area under the curve remains the same The smearing caused by the calculation errors can be decreased by placing a window on the FFT block samples in such a way that the ends of the FFT block are smoothly tapered to zero and discontinuities do not occur when the FFT treats the windowed block as one period of a periodic signal Each sample of the FFT block is therefore multiplied by a factor whose size is dependent on the position of the sample in the FFT block The software supports six different windows rectangular all data is not changed Hanning sinusoidal Hamming sinusoidal Bartlett sinusoidal Blackman triangular Parzen triang
74. is file can be edited in any ASCH editor but it is recommended not to do so to avoid invalid combinations of settings Restore instrument settings from disk When a certain kind of measurement is done often it is useful to save the instrument setting on disk and restore it each time it is needed This will avoid each time setting up the instrument in the same way To restore instrument settings from disk enter the File menu in the oscilloscope data logger or spectrum analyzer and select the Restore instrument settings item A restore dialog will appear in which a drive a directory and a file name can be selected After pressing the OK button the file is loaded and all instruments are set according the settings in the file Storing measurement data on disk To save measured data for later examination it can be stored on disk This can be done in two ways by activating the Write waveform to disk item from the File menu in the oscilloscope data logger or spectrum analyzer or by click ing the Write waveform button e Note The voltmeter has a completely different way of storing measurement data to disk This will be discussed in the chapter voltmeter Both ways will bring a save dialog in which the drive the directory and the filename can be entered When a name 1s entered and the OK button is pressed all waveforms will be saved together with the settings of the instrument and the references Three files are written a
75. ise component s will disappear and the actual signal remains Averaging can be switched on by selecting the item Perform averaging of from the Measure menu In the next menu a number of measurements can be selected that have to be averaged The item 1 measurement will switch off averag ing When averaging is set to e g 20 measurements and the spectrum analyzer is set to Pause pressing the One shot but ton will result in taking 20 measurements which are averaged Measuring maximum values The spectrum analyzer can be set to measure and display only the maximum values of the spectral components After a number of measurements the highest value of each spectral component is displayed then To enable measuring maximum values enter the Measure menu and select the choice Measure max values A check mark in front of the menu item indicates whether measuring maximum values is switched on or off The Spectrum Analyzer 66 DI 770 and WINDAQ Scope Manual Note The display of maximum values is reset when the instrument setting changes Hint This mode can be useful when the frequency response characteristic of a device needs to be determined Apply a frequency sweeped signal and switch on Measure max values and the characteristic will be created Measure the Total Harmonic Distortion of a signal With the spectrum analyzer it is possible to measure the Total Harmonic Distortion of a signal The THD is defined as 2 2 2 2 2 2 2 2 2 ss
76. itched on a check mark is placed in the menu item To switch Scaling references off select the Scale references item again Software 26 DI 770 and WINDAQ Scope Manual Update reference comment When a measurement is taken three lines of comment text can be added to the measurement This text is saved to disk together with the waveform data and printed out with the waveform See Add comment text to a measurement When the reference channels are filled with data from a file and the comment text has to be changed this can be done using the item Update comments from the Reference menu After activating the item a dialog appears in which the three lines of text can be entered changed When the dialog is closed with the OK button the new text is automati cally saved to disk Documentation of measurements In the oscilloscope the data logger and the spectrum analyzer several features are available to document measure ment data Add comment text to a measurement For explanation and documentation each measurement can be supplied with three lines of text This text will be saved together with the waveform data when the waveform is written to disk The text will also appear on a hardcopy printout To enter the text open the Settings menu and select the item Comment A dialog appears in which the three lines of text can be typed To switch between the three lines use the mouse or the lt Tab gt key Note The text remai
77. lations will be done until the option is enabled Show measurement name The Oscilloscope 43 DI 770 and WINDAQ Scope Manual Show measured value Show measurement unit To reduce the space used by the window on the screen the measurement name value and or unit can be hidden This results in the disappearance of the corresponding column which results in a smaller window Display font By selecting this option the font which is used to display the strings and values can be changed The font settings which can be changed are font name font style font size and the font color Background color By selecting this option the background color can be altered Some font colors e g light green are not showing up very good on a white background Change the background color to e g black for a better result Selecting the active channel The cursors can only calculate values for one channel The buttons in the left top of the window caption bar can be used to select the channel from which data is used to cal culate the selected measurements There are two ways to change between channels pressing the buttons with the mouse or by using the corresponding number on the keyboard Showing or hiding the cursor readout The left button of the two in the right top corner of the window caption bar can be used to hide e or show Ep the grid with measured data When hiding the data the height of the window equals the height of the window
78. le instrument can have its own settings file Selection of the file is done by pressing the Change file name button on the Active instruments page In the appearing dialog the file can be selected The name of the selected file will be displayed in the Instrument settings file box Software 23 DI 770 and WINDAQ Scope Manual To clear the file name press the Clear button Note When more than one instrument is selected to be switched on at start up the settings file associated with the instrument with the highest priority will be loaded The priorities in file loading are highest the data logger then the oscilloscope then the voltmeter and lowest the spectrum analyzer Saving instrument settings on disk When a certain kind of measurement is done often it is useful to save the instrument setting on disk and restore it each time it is needed This will avoid each time setting up the instrument in the same way To save the instrument setting to disk enter the File menu from the oscilloscope the data logger or the spectrum ana lyzer and select Save instrument setting A save dialog will appear in which a drive and directory can be selected and a name for the setting can be entered If an invalid file name or a name of an existing file name is entered a warning will be displayed The settings for all instruments are saved in one file This file has the extension SET It is an ASCII file in a Win dows INI format Note Th
79. ll get a value that is related to this value and differ from it with 10 dB per division when Soft ware gain is set to 1 The measured data will be transformed to logarithmic data as well Selecting the axis type can be done by entering the Chl menu choosing the Axis type menu and selecting the axis type The axis type can also be set by the keyboard using the following keys lt L gt toggle the Chl axis between Linear and Logarithmic lt Shift L gt toggle the Ch2 axis between Linear and Logarithmic The Spectrum Analyzer 62 DI 770 and WINDAQ Scope Manual Note Due to smearing errors caused by discontinuities See Windowing and within specifications distortion in the Analog to Digital Converter non existing frequency components will show up when a logarithmic axis is selected These components are all outside the dynamic range of the measurement system To avoid confusion with these non existing frequency components the logarithmic graph can be clipped on the theo retical dynamic range of the measurement system This is done by selecting the Vertical log axis range item from the Settings menu and choosing either Not clipped or Clipped conform hardware specs Setting up the frequency range Along the horizontal axis of the screen the frequency of the measured spectrum is projected Magnifying the frequency axis and horizontally positioning the signal is done in the same way as in the oscilloscope and is therefor not disc
80. llowing e The signal generator which is part of the hardware instrument Not all instruments do have a signal generator In that case the button is not visible e The program setup e The online help e The exit button Starting the program The program can easily be started by using the program group created by the setup program By double clicking the icon with the same name as the hardware instrument you are using the program is started Now an intro screen will appear with the logo the instrument name the program version number and the copyright notice After a few seconds the intro screen disappears and the instrument taskbar appears If in the program setup any instru ments are set to be active at power up these instruments are switched on as well Help For all instruments online help is available by pressing the Help button in the instrument taskbar or by pressing the key lt F1 gt in a window Controlling the instruments All instruments are controlled by use of the mouse the keyboard and by menus Software 19 DI 770 and WINDAQ Scope Manual Keys that can be used lt space gt Force a trigger oscilloscope lt I gt Toggle reference 1 lt 2 gt Toggle reference 2 lt Ctrl 4 gt Move the left side of the record view scrollbar to the left lt Ctrl gt Move the left side of the record view scrollbar to the right lt Alt lt gt Move the right side of the record view scrollbar to the left
81. m can have different sources to determine when measuring has to start These sources are Trigger on channel 1 Trigger on channel 2 External Trigger on the external trigger input Chl AND Ch2 Trigger on channel and channel 2 the signals on both channels have to meet their trigger set tings Chl OR Ch2 Trigger on channel 1 or channel 2 only one of signals has to meet its trigger setting The Oscilloscope 38 DI 770 and WINDAQ Scope Manual To change the trigger source enter the Trigger menu and select the Source item In this menu a source can be selected The trigger menu can be found in the main menu and can be called by clicking the trigger button Ej or by pressing the right mouse button when the mouse is over one of the trigger controls or readouts Selecting the trigger mode The trigger system has several trigger modes Rising slope trigger on the rising slope of a signal Falling slope trigger on the falling slope of a signal To change the trigger mode enter the Trigger menu and select the Trigger mode item A menu will popup and a trig ger mode selection can be made Another way to change the trigger mode is by using the trigger symbol Double clicking the left mouse button on the trigger symbol will change the trigger mode from Falling slope to Rising slope Rising slope to Falling slope Setting the trigger level Adjusting a trigger level can be done is several ways by means of a menu or by usi
82. measuring at voltages higher than 25V AC or 60 V DC e Measuring directly on the LINE VOLTAGE can be very dangerous The OUTSIDE of the BNC CONNECTORS at the DI 770 are connected with the GROUND of the computer e Use a good isolation transformer or a differential probe when measuring at the LINE VOLTAGE or at GROUNDED POWER SUPPLIES e Incase this has not been considered and the GROUND of the DI 770 is connected to a positive voltage a short circuit current will be flowing Because of this short circuit current both the DI 770 and the computer can be damaged Introduction 1 DI 770 and WINDAQ Scope Manual Sampling When sampling the input signal samples are taken at certain moments The frequency at which the samples are taken is called the sampling frequency By taking a large number of samples the input signal can be reconstructed SA y j y A The more samples are taken the better the signal can be reconstructed The sampling frequency must be higher than 2 times the highest frequency in the input signal This is called the Nyquist frequency Theoretically it is possible to reconstruct the input signal with more than 2 samples In practice 10 to 20 samples are necessary to be able to exam ine the signal thoroughly Aliasing If the sampling frequency is lower than 2 times the frequency of the input signal aliasing will occur The following illustration shows how aliasing occurs Pal Os
83. mment label to delete and press the right mouse button A menu will pop up Select the Delete comment item to delete the comment label Make a hard copy print out To save a measurement on paper a WYSIWYG hardcopy utility is added The printout contains all active signals with the settings at the moment of activating the hardcopy function All rele vant information about the signals sensitivity offsets gains sampling frequency record length etc are placed around the signal display A record view indicator is placed in the upper right corner of the printout indicating which part of the measured record is displayed where the trigger point is located and where the cursors are located in the record if switched on If cursors are switched on the cursors are drawn when in the display and a table with the cursor readout is drawn If comment labels are placed they are printed in the same way as they appear on the screen The hardcopy can be activated in three ways using the key combination lt Ctrl P gt using the print button 3 A or by entering the File menu and selecting the Print item A print dialog appears in which the current selected printer is indicated To change the selected printer or the settings of the selected printer press the Setup button A new dialog appears in which another printer can be selected or the settings of the current printer can be changed Note In theory all paper sizes are supported but envelope
84. mpling the input signal The hardware method can be realized by selecting the Channels option from the Settings menu Type the offset in the DC hardware offset edit box This voltage will be added to the input signal If a voltage has to be subtracted enter a negative value The Voltmeter 47 DI 770 and WINDAQ Scope Manual Configuring the displays The voltmeter can display the measured values in several different ways in up to six displays Below the display a bargraph is showing the value in the display in a graphic format By activating the choice Displays from the Settings menu a dialog appears in which the settings of all the displays can be changed This method works always even if the display and bargraph for which the settings are changed are invisible x Measurement Display measured value cht gt X Cancel Units of measure Volt Numbers precision Auto Units per measurement unit 10000 000 1 0000 000 Set low value 99999 000 99999 000 set high value L 99999 000 99999 000 Set impendance value 0 001 20000 000 Set relative value 99999 000 99999 000 Relative measuring h Show display M Show bar graph These settings can also be done by placing the mouse cursor over a display and pressing the right mouse button A popup menu appears with all settings for that display This method only works if the display or bargraph 1s visible All settings applied to a display are also applied
85. ng the special trigger symbol To change a trigger level by means of a menu enter the Trigger menu and select the Level Ch1 or Level Ch2 item An input dialog appears in which the trigger level can be entered in volts In this dialog also a check box for selecting auto level triggering is found When auto level triggering is selected the trigger level will be set to a value that lies in the middle between the highest and the lowest value of the previous measurement This can be very useful with continuously changing signals When auto level triggering 1s selected the trigger symbol will show that with a letter A in the symbol The level can no longer be adjusted with the symbol Note When a trigger source External is selected the trigger level adjustment is disabled Setting the trigger hysteresis Adjusting a trigger hysteresis can be done in several ways by means of a menu or by using the special trigger sym bol To change a trigger hysteresis by means of a menu enter the Trigger menu and select the Hysteresis Ch1 or Hyster esis Ch2 item An input dialog appears in which the trigger hysteresis can be entered in volts When auto level triggering is selected the trigger symbol will show that with a letter A in the symbol The hysteresis can still be adjusted with the symbol Note When a trigger source External is selected the trigger hysteresis adjustment is disabled The trigger symbol The oscilloscope is equip
86. ngth of the scope has to be set to 1024 points for linear mode to any required length but 64K is preferred e If possible the sampling frequency of the scope has to be set in such a way that exactly 1 period of the signal is captured in the 1024 points or 64K points After the signal is measured it can be saved to disk using Save waveform from the File menu Setting the function generator At the left hand side of the display in the generator a number of signal shape buttons are located one of them is named File With this button a signal from a file can be selected and loaded into the generator Pressing this button will pop up a file selection dialog in which the proper waveform file can be selected After reading the signal the amplitude and frequency of the signal can be adjusted using the proper controls The Function Generator 74 DATAQ INSTRUMENTS DATAQ Instruments Inc 241 Springside Drive Akron Ohio 44333 Telephone 330 668 1444 Fax 330 666 5434 E mail support datag com Direct Product Links click on text to jump to page Data Acquisition Data Logger Chart Recorder Thermocouple Oscilloscope
87. nnnncnnnnnnonononononnnnnnnnnnnnononnnnnnnnnnnnnnnononnnnnnccninnnnnnos 22 Restore factory Calibration TaACtOrS iien a tint heseiueeseui Gian eentns ces cb tales elses 23 Loading a set of calibration values at StartUp iii 23 SCIECUING The type OL CUILY CY Cle dada 23 PNCTIVG MS mental Star iniciaba 23 Saving Instrument et nos On ISK is dias 24 Restore mmstruimient Settings OM ISK A 24 Storine Measurement data OM dISK us dina ET 24 Settine me data Het ia 24 Loading saved measurement data from disk oooonnnnnnnnnccncnononoonnnnnnnnnnnnonnnnonannccnnnnnnnnnnnnnninnncncnnnnnnnns 25 Settine the Waveform read Method A A A A 25 Comparing signals using the reference channels ooonnnnnnnnncccnnnnononnnnnnnnnnnnnnononononnncnnnnnnnnnnnonaninnnnss 26 Ud ks 0 eS A NTU re pe rn te oreo en eT On eer ee ane 26 S WICC references ON OF OLE sida 26 Ror d WTA Us Mente Oe Oe mT ree BGT RONDE ONE Ota ane etre PNT MP anne RE Tn Rpt CEN TEM NaS SN eT 26 Update Teterence conmemora 27 Documentation OR me as Urna lios 2 Add comment text 10 a mensure men enra naa E AE n 27 Place a commentiaDe Lille 27 Edita Comment label A A mie needed 27 Dekun a commnent labe Ll ti o ias 28 Make a hard copy PU i 28 Endine THE PNG PAI e caia 28 0 The Osciloscopio cc Ea a 29 O O 30 Displays AM o adas 30 PEDIC OJOS MOI odiaba 30 A A dalai cect 31 IVC TO CS eins 31 serie Up a channel sa tl lidia 32 Settino the sensitivity OF cd cOn ed 32 settine the signal co
88. ns aed 53 Fast ANG asus dd dial 53 ROTTS SIO TNE ASC MN 0 160 AO ARPA RN O meena seesaseseeaneutona 53 Storie measurement values O1n disk Or paper oec E AE A adnan acne 54 Setting the time between WO measure Menis rne a a AN 54 Setimo Mestres ti la 54 SOT A CMS OD a a 54 9 The Data LOC Ger Ai NATA SIA teaesceaseuesvacawossconsesstaneeserenuscesessecsesveseuanvecetesseaess 55 The data los ser me asurido SST caren wee ssnccun axl mvacGut vaccine eure cco N 55 Displaying channe IS serieren a ii 56 Seno upa Chane i e en a a E N E E N 56 Table of Contents Vil DI 770 and WINDAQ Scope Manual Seno GINS ME ARIS suas siete ats see A A A de 56 Sene UP He sample SPCC A cace ind eae E teaneee tices 56 Seline therecord VEN CUI tasa 57 Sethe thie NOMmZOntal AXIS CY Pe serian aS 57 Por oror Meas Uremic MOa Io 57 SEI TNS ASU I AA EE e o E P E E E A AE E E E ONA E E 57 ONEA r a A A EN 58 CLOUT AA E N E EA A AI A OE EE A E Gac 58 Comparing signals using the reference channels vin i ees 58 Perl ormins Cursor measure MENiS sasien aa a a 58 9 The Spectrom ANAIYV AA 59 DESCrIp OOO reli iaa adi 60 AMAS iaa 60 WW ANG OMY MED is 61 Displayine Chameleon biira 61 A E E soaceenes 62 Settine the AN PUL Sens lo ars 62 Logarithmic or linear vertical Sica 62 setine Tip TheITequenCy Tadeo ala 63 Seran Up Meegen y AXSI De ii sais 63 Settino the MeQUeNCY TANCe esti ei 65 Sete The SpecT record leno th pyri tisde satis ac Pret acti a E E 65 91100
89. ns the same until new text is entered or the lines are cleared So when text is entered and more than one waveforms is saved or printed each waveform will have the same comment Place a comment label When documenting a measurement it can be useful to add some comment to a specific part of the signal This can be done with the special comment labels These comment labels are placed within the signal display at a specific position in relation to the waveform The comment labels contain text and can have an arrow pointing at a specific point of the waveform The shape the colors and the arrow can all be customized to your specific wishes When printing the measurement the comment labels are placed as well To place a comment label press the comment label button p or activate the Add a comment label item from the Settings menu The comment label is now placed within the signal display It can be dragged to any position with the mouse and the arrow can be dragged to any position as well The comment labels are waveform based when the record view offset or the record view gain changes the position of the comment label remains the same in relation to the record Edit a comment label To change the properties of a comment label place the mouse pointer on the comment label or the arrow of the com ment label and press the right mouse button A menu will pop up in which all properties can be edited Comment text With this item the text in t
90. of the input signal is passed through It is then possible to examine e g a 20 mV ripple on a 30 V DC voltage since only the ripple is passed through and the DC voltage not AC voltages with a frequency lower than 4 Hz are not coupled correctly There are three different ways to set the coupling Two ways are by clicking the coupling button or by pressing keys The third way is through the channel settings dialog The channels setting dialog is called by selecting the Channels option from the Settings menu In this dialog the signal coupling setting is available In the tool bar for each channel a coupling button is found the coupling button for Ch1 at the left hand side of the screen for Ch2 at the right hand side of the screen The picture at the button indicates the state of the coupling setting The left button of the two buttons below is indicating AC coupling the right button is indicating DC coupling ME The current coupling state is displayed in the coupling button The keys which can be used to change the signal coupling are lt A gt sets the coupling of channel 1 to AC lt D gt sets the coupling of channel 1 to DC lt Shift A gt sets the coupling of channel 2 to AC lt Shift D gt sets the coupling of channel 2 to DC Setting a DC hardware offset The signal offset is adjustable in two ways a hardware method and a per display software method Using the hardware method an adjustable DC voltage is added before sa
91. om O to 16 Volt full scale The sensitivity can be set through the Sensitivity menu The Sensitivity menu is called by enabling the Chl menu and then selecting the Sensitivity menu In this menu the input sensitivities are available In the spectrum analyzer also an Autoranging setting is available The Sensitivity menu can also be entered by clicking the right mouse button over one of the Chl or Ch2 controls and readouts To switch on Autoranging a special button is available When autoranging is switched on the button caption is Auto otherwise it holds the current set input sensitivity Pressing the right mouse button on this button will bring up a menu with all sensitivities Note When Autoranging is switched on several measurements might be needed to set the input sensitivity properly depending on the input signal Another way to set the sensitivity is by using the keyboard A few keys have been reserved for setting the input sensi tivity of the channels These keys are Increase Ch sensitivity Decrease Ch1 sensitivity Increase Ch2 sensitivity Decrease Ch2 sensitivity Logarithmic or linear vertical axis The vertical axis of the spectrum analyzer can be set to linear or to logarithmic When set to linear the normal axis is used running from 0 to 2 x Sensitivity When set to logarithmic the position on the linear axis that is mark ed Sensitivity will get the value Value 20 x log Sensitivity The rest of the labels wi
92. ons and a user defined option The pre trigger value options are default given in a percentage but can be given in a number of samples or in time To do that first the user defined option has to be selected The Time base menu can also be entered by pressing the right mouse button over one of the time base controls or read outs When the user defined option is selected a dialog box appears In this dialog box can be selected in what unit the pre trigger value has to be entered percentage samples or time and what the pre trigger value has to be When the dialog box is closed using the OK button the entered value is accepted and the selected unit will be used the next time the pre trigger value menu is called Mouse sensitivity pre trigger position adjustment For adjusting the pre trigger value by dragging the slider of the pre trigger position scroll bar the mouse sensitivity can be adjusted from course to fine from 4 steps per screen to 100 steps per screen When a mouse sensitivity of 4 steps per screen is selected the pre trigger position scroll bar is divided in 4 positions Each mouse movement will adjust the pre trigger value to the next position in the direction the mouse is moved So the available pre trigger positions are 0 25 50 75 and 100 The Oscilloscope 36 DI 770 and WINDAQ Scope Manual When a mouse sensitivity of 10 steps per screen is selected the available pre trigger positions are 0 10 20 30
93. ounds LO HI FAIL and PASS at one time Resetting the minimum and maximum values When displaying the measured values the maximum value ever and or the minimum value ever can be displayed These values are kept until the software is closed To reset the minimum and maximum values for each channel a reset button is available in the speedbar EJ W and through the settings channel menu By pressing this button the maximum value is set to the lowest possible mea sured value The minimum value is set to the maximum measured value possible Performing measurements Hint Use the frequency meter to determine the frequency of the input signal When the device voltmeter is switched on and the measurement process is not in one shot mode measurements take place The measured values are displayed continuously If the oscilloscope is active the trigger conditions also apply to the voltmeter Start and stop measuring The measuring can be halted by pressing the pause button 00 or lt S gt key The oneshot button Me next to the pause button becomes available lt O gt key and the pause button changes to a play button pe The measuring can also be halted by selecting the Stop continuous measuring option from the Measure menu The option Perform a single measurement becomes available and the Stop continuous measuring option changes to Start continuous measuring Averaging Normally the voltmeter adds the two previous measured values wit
94. paper sizes will give unusable results Selecting land scape or portrait has no use since the hardcopy function forces landscape When the correct printer is selected and all settings are made press the OK button to leave the dialog Press the Can cel button to leave the dialog without changes The check box Color print out determines whether a color printout is made or a black and white printout is made When this box is checked and the printer supports colors a color printout is made If the printer does not support col ors different shades of gray are created by the windows printer driver If the box is not checked only black is used To start printing now press the Print button A dialog appears indicating that the hardcopy is generated and sent to the printer Ending the program With the right most button in the instrument taskbar the application can be terminated The application settings and instrument window positions are saved on disk Software 28 DI 770 and WINDAQ Scope Manual 6 The Oscilloscope The oscilloscope is an instrument with which electrical voltages varying in time can be displayed With the oscillo scope time dependent electrical signals can be examined easily The oscilloscope has separated voltage inputs channels which can be configured individually It is a digital sampling oscilloscope That means that the oscilloscope takes samples at fixed times From each sample the value is deter mined an
95. pear in which a file with calibration values can be selected If an illegal file is selected or can cel is pressed the check box will be untagged Pressing the Restore factory cal button will override the values from the file When loading calibration values from a file is enabled and a different file has to be loaded this file can be selected by pressing the Change cal file button at the Hardware page If cancel is pressed or an illegal file 1s selected no changes are made to the current selected calibration file Selecting the type of duty cycle The software can use two different types of duty cycle calculation e The normal duty cycle setting displays the percentage of which the period is high e The inverted duty cycle setting displays the percentage of which the period is low Selection can be made on the Duty cycle page by selecting one of the two radio buttons The pictures next to the radio buttons display the two types in a graphical way Active instruments at start up At the Active instruments page a selection can be made which instruments have to be switched on at start up of the software Place a check in the check boxes of the instruments that have to be switched on at start up of the software Note The data logger can not be activated at the same time as one of the other instruments When at least one instrument is selected it is possible to select a settings file that has to be loaded at start up as well Each sing
96. ped with a special trigger symbol that is used to adjust the trigger level the trigger hystere sis and the trigger mode The WYSIWYG trigger symbol is found at the left hand side or the right hand side of the signal display depending on the trigger source adjust trigger level adjust trigger hysteresis The Oscilloscope 39 DI 770 and WINDAQ Scope Manual In the above picture the trigger mode of the left hand symbol is set to Rising slope and the trigger mode of the right hand symbol is set to Falling slope To adjust the trigger level using the trigger symbol place the mouse pointer on the trigger symbol in the area that is marked adjust trigger level in the above picture The mouse pointer will change to a symbol Press the left mouse button and drag the trigger symbol to the correct position while keeping the left mouse button pressed While drag ging the trigger level is adjusted according the position of the trigger symbol on the screen When the mouse button is released trigger level adjustment stops and the normal mouse pointer shape is returned To adjust the trigger hysteresis using the trigger symbol place the mouse pointer on the trigger symbol in the area that is marked adjust trigger hysteresis in the above picture The mouse pointer will change toa symbol Press the left mouse button and drag the hysteresis level of the trigger symbol to the correct position while keeping the left mouse button pressed While
97. play Mode Envelope Averaging Math mode Polarity Vertical position setting Vertical gain setting Input coupling Time base minimum Time base maximum Time base gain Time base accuracy Record length Record view scroll bar gain Trigger mode Trigger system Trigger source Trigger level Pre trigger Post trigger Trigger delay Trigger hysteresis Trigger hysteresis resolution Auto disk measuring Auto setup Zooming Cursor system Cursor mode Cursor measurements CH1 CH2 CH1 and CH2 On Off 1 256 averaging CH1 CH2 CH1 CH2 CH2 CH1 Normal Invert 200mVolt 500mVolt 1V 2V 5V 10V 20V 40V 80 Volt full scale 0 25 to 8 magnifying AC DC 20 day s div DI 770 25 400nsec div DI 770 100 100nsec div 0 25 to 8 magnifying 100 ppm from 0 C to 70 C Aging 5ppm per year 1 to 131060 samples per channel l to 125 free run delayed run auto single edge triggered window peak exter nal two digital trigger levels 4096 positions CH 1 CH2 External Keyboard and Master 0 100 full input range 1 to 131060 samples per channel 1 to 131060 samples per channel 1 to 131060 samples per channel 0 to 100 full input range 0 025 full scale 1 to 1000 file s connect and show mouse window control gain vertical and gain horizontal two cursors auto tracking auto correct points large cursors small cursors rise time left rise time right sample time left sample
98. ples in Roll mode than in Scan mode To set the scroll mode enter the Measure menu select the item Scroll mode and choose between the two possibilities Comparing signals using the reference channels To make the data logger keep up with the measuring hardware longer references can be switched off while measur ing To do this open the References menu and select the Show references while measuring item When the item Show references while measuring is checked switched on references are shown while the data logger measures If the item is not checked the references are switched off when the measurement is started and switched on again when the data logger is ready Performing cursor measurements Like in the oscilloscope the data logger has a set of cursors to perform measurements on the displayed signals The cursors in the data logger work exactly like the oscilloscope so refer to chapter 2 the oscilloscope for an expla nation on how to work with the cursors The Data Logger 58 DI 770 and WINDAQ Scope Manual 9 The Spectrum Analyzer The common way to examine electrical signals is in the time domain using an oscilloscope The time domain is used to determine amplitude time and phase information which is necessary to describe the behavior of an electrical sys tem Not all electrical systems can be characterized in the time domain Circuits like filters amplifiers oscillators mixers modulators and detectors can be
99. ponding button will be raised Clearing To clear a stored preset it first needs to be selected by pressing the corresponding button The clear button will become active Pressing this button will clear the preset position and make the location available for a new preset The corresponding button will be disabled Performing a sweep The function generator offers in combination with the spectrum analyzer the possibility to generate a signal with a frequency sweep For this purpose the spectrum analyzer needs to be active as well After each measurement the spectrum analyzer per forms the frequency of the generator is increased with a certain step size until the highest value is reached In that case the frequency will be set to the lowest value off Juweep _ Below the signal shape buttons is a sweep button located for setting the sweep parameters Next to the button there is an on off button for switching the sweep function on and off When the sweep button is pressed the sweep generator settings dialog is displayed Sweep generator settings EJ Sweep generator settings C Fully controlled by spectrum analyzer Manual Start frequency 1953125 Hz Stop frequency 000000 Hz Frequency step related to spectrum length Frequency step 1953125 Hz In this dialog all settings of the sweep can be made The easiest setting is Fully controlled by spectrum analyzer In this setting the setting of the frequency axis of t
100. re of the vertical axis can be changed After activation a popup menu with 13 choices appears The unit that is selected is displayed at the top of the vertical axis It is also placed on the paper when printed out When activating the choice User defined a dialog box appears in which a custom unit can be entered with a maximum length of 5 characters The Units of measure popup menu can also be called by clicking the right mouse button over the vertical axes If you are measuring e g with a temperature probe you can choose DEGREE C for the units By activating the choice Units gain from the Chl menu a multiplication factor can be entered for the units of the vertical axis A dialog box appears in which the factor can be entered The numbers along the vertical axis are multi plied by the factor and replaced by the result If you are using a 10x probe you can by means of units gain enter the value 10 to get correct numbers along the ver tical axis Another application is when measuring with a temperature probe Suppose the temperature probe gives a voltage change of 1 volt at a temperature change of 5 degrees By entering the factor 5 the temperature change is displayed directly in the number of degrees The Oscilloscope 34 DI 770 and WINDAQ Scope Manual It is also possible to add an offset to the numbers of the vertical axis In the dialog box called by activating Units off set from the Chl menu an offset can be ente
101. red This offset is added to the numbers along the vertical axis Nothing is done to the signal An application for this is the temperature measurement Suppose the output voltage of the temperature probe at 0 C is 10 Volt By entering a units offset of 10 the zero level of the axis is changed in a way that the absolute temperature is directly readable Mouse sensitivity for the vertical axis For dragging the vertical axis the mouse sensitivity can be adjusted from course to fine from 1 step per division to 25 steps per division When a mouse sensitivity of 1 step per division is selected each mouse movement will make the software offset become one division larger or smaller When the software gain is adjusted it will result in a two division smaller or larger signal size one division at the top and one division at the bottom of the signal When the mouse sensitivity is set to 25 steps per division each mouse movement will result in an offset change of 1 25th division or a signal size change of 2 25th division The mouse sensitivity can be set by selecting the item Mouse sensitivity vertical axis from the Chl menu Setting up the time axis Along the horizontal axis of an oscilloscope the measuring time is projected The measuring time is determined by the number of samples that is measured and the sample frequency Setting the sample frequency The sample frequency determines the speed with which the instrument will take samples o
102. s R1 and R2 R1 is a reference channel for channel 1 and R2 is a reference channel for channel 2 These reference channels are filled once and remain unchanged while measuring The references only change when new data is stored in the references Fill the references To fill the reference channel s two ways are available copying the current displayed signals to the reference chan nels or read previously saved waveform data from disk To copy the current live signals to the reference channels either press the corresponding button on the speed button tool bar EJ or select the item Copy live to refs from the References menu This will copy the waveform data from the active channel s to the corresponding reference channel s The settings of the channel s will also be copied to a special reference setting If the reference channel s was were not yet displayed it is they are switched on as well To fill a reference channel with data from disk see the paragraph on Loading saved measurement data from disk The data in the reference channels will remain unchanged until new data is stored in the reference channels The ref erence channels are displayed with the same record view offset and record view gain as the live channels Changing the pre trigger value will not affect the reference channels When the record length of the live channels is changed to a shorter record after filling the reference channels less data of the reference channels
103. s are correct though Sound settings With comparison measurements for each value a sound signal can be set When this is done the set limits are indi cated audibly By activating the choice Sounds from the Settings menu a dialog appears from which for each display value a sound signal can be set For each display value can be chosen from No sound 100 Hz 200 Hz 500 Hz 1 kHz 2 kHz 5 kHz and 10 kHz With the choice No sound no sound signal is generated with the selected display value If you are using the PC speaker or a WAV device it is only possible to make one sound at a time This means that the sound which is played first is repeated until the condition is invalid As soon as the condition is invalid the sound for the next condition can be played Note If your computer is equipped with a digital playback soundcard a soundcard which can play WAV files you can also play the sounds through your soundcard Select the sound device pull down after which you can select wav device from the list If this option is missing and you have a soundcard you should install drivers for the soundcard or you don t have a digital playback soundcard The Voltmeter 52 DI 770 and WINDAQ Scope Manual Note If the computer is equipped with a soundcard it is also possible to select the MIDI device option The MIDI device uses the instrument settings as defined in the General MIDI standard When using MIDI it is possible to play all four s
104. s then changed By activating the choice Frequency range from the Settings menu a popup menu appears in which several frequencies are available The frequencies indicate the center frequency of a frequency range in which the voltmeter measures properly The size of the frequency range is determined from 0 2 x feenter to 5 xf center When Auto freq is chosen the voltmeter determines the best frequency setting by itself For each measurement the frequency has to be determined resulting in a longer time before updating the displays Note The Auto frequency setting overrides the sample frequency setting in the oscilloscope and the spectrum ana lyzer This will result in a less usable display in those instruments To avoid this the choice Scope freq is available in the menu The voltmeter will use the same sample frequency as the oscilloscope or spectrum analyzer Displaying channels The voltmeter has several modes to display the two channels To select the measure mode enter the Settings menu and select Channels Use the Measure channel option to enable or disable measuring from a channel Measuring takes place from at least one channel When only one channel is measured the controls of the other channel are disabled or removed from the display Setting up a channel The channels of the voltmeter can be setup in several ways Both channels have the same settings so only channel 1 is discussed here Setting the input range In
105. sition a cursor pair Hint To position an off screen cursor bring the mouse pointer to the edge of the signal display at which the cursor exceeds The mouse pointer will change shape Now press the left mouse button and drag the cursor to the correct position When that is reached release the left mouse button The original mouse pointer shape is restored Setting up the cursor measurements With the cursors it is possible to measure the input signal s in several ways To set up the cursor measurements press the settings button at the cursor readout window the right most button at the left top of the window caption A menu appears containing the following options The menu can also be called by pressing the right mouse button over the table Voltmeter measurements All measurements which can be selected in the voltmeter measurements submenu are also available in the voltmeter The only difference between the measurements is that the voltmeter uses the previous two measurement values and The Oscilloscope 42 DI 770 and WINDAQ Scope Manual the current measured values which are added together and meaned before the value is displayed For a complete description of the measurements see the chapter on the voltmeter Time Rise time left the rise time of the signal at the position of the left cursor is determined The rise time is determined by finding the closest zero crossing max min 2 relative to the cursor position Next the
106. sted line This text is saved when the application 1s closed and loaded when the application is started Device info In the lower part of the Common page some device info is given Information that is displayed is e The hardware device e The address where the hardware is found e The resolution of the hardware Depending on the hardware device some extra info can be displayed e The date of the last calibration e The serial number Setting the date and time style At several places in the program dates and or times are displayed The way they are displayed can be set at the date and time page For both the date and the time several styles are available to select from Search hardware When the software is started without an instrument a dialog appears to notify the user that the instrument is not found It is possible to press Ignore to be able to examine previous saved waveforms When the instrument is then attached to the computer it can be searched and activated by pressing the Search hardware button on the Hardware page Manually adjusting of calibration factors By selecting the Adjust cal values button at the Hardware page a dialog appears in which the current calibration val ues of the instrument can be changed Software 22 DI 770 and WINDAQ Scope Manual The dialog has a grid in which for both channels the gain and offset calibration values can be adjusted On the right are the following buttons Continue T
107. t programs Files in ASCII format are much larger than files in binary format up to 7 times To set the file type enter the File menu and select the item Data file type Choose the requested setting from the menu Loading saved measurement data from disk Previously saved waveforms can be read from disk in the oscilloscope data logger and the spectrum analyzer There are two ways to do this by activating the Read waveform from disk item from the File menu or by clicking the Read waveform button Both ways will bring up a load dialog in which a drive directory and file can be selected When a file is selected and the OK button is pressed the waveform will be read from disk Each waveform consists of three files a DAT file a GEG file and a REF file If one of these files is missing or the waveform data is not compatible an error is generated The data file type in which the data is written will be determined by the software and the correct reading functions are used Then the data is read according to the Waveform read method that is set After reading the data the instrument is set to Pause not required in the data logger to avoid the data being replaced by new measured data Note Measurement data stored in the voltmeter can be read in the oscilloscope and the data logger The values of display 1 of channel 1 will be placed in channel 1 of the data logger The values of display 2 of channel I will be placed in Referen
108. t value change exceeds the hysteresis value the input value will be stored By activating the item Hysteresis from the Acquisition menu a dialog appears in which the hysteresis can be entered The hysteresis is entered as a percentage of the last measured value With each new measurement the size of the hys teresis in volts is recalculated The hysteresis can only be set with an acquisition time smaller than 0 5 seconds Start an acquisition By activating the choice Write data from the Acquire menu a menu is shown with which a selection can be made to write to disk or printer The choice Disk will cause the measurement data to be stored on disk After activating the choice a save dialog appears in which the drive directory and name of the file can be typed If the typed file already exists an overwrite prompt will appear The measuring will start after this At fixed times a measurement is taken and stored on disk Measuring can be aborted by pressing the cancel button The choice Printer will cause the measurement data to be written to the printer After activating the choice a print dia log appears from which a printer can be selected A dialog will appear in which the title of the job can be typed Now measuring starts At fixed times a measurement is taken and sent to the printer Measuring can be aborted by pressing the Cancel button The printing and writing can also be activated by pressing the following buttons on the speedbar
109. t will be set up for a new measurement and immediately a trigger pulse is generated without waiting for a trigger This can be useful when e g a slowly changing DC level has to be monitored on which can t be triggered In the dialog also a check box for an infinite time out is available When this box is checked the software will keep waiting for the input signal to meet the trigger settings without ever forcing a trigger pulse This can be very useful in one shot measurements and with auto disk measuring Performing measurements When the oscilloscope is completely set up measurements can be performed By default the oscilloscope is always measuring and displaying Changes that are made in the settings can be made while measuring and will be executed while measuring so the effects are immediately visible Stopping the measurements To avoid a new screen of measurement data replacing an old screen measuring and displaying of data can be stopped This can be done in several ways by pressing the Pause button 00 by pressing the lt S gt key or by activating the item Stop continuous measuring from the Measure menu The Oscilloscope 40 DI 770 and WINDAQ Scope Manual When measuring is stopped the latest measured data will remain on the screen The Pause button changes to a Play button Fr and the One shot button i becomes available The measured signal can now be examined To perform a single measurement press the One s
110. that one fre quency is dominantly present The Spectrum Analyzer 59 DI 770 and WINDAQ Scope Manual e In the frequency domain it is very simple to determine carrier frequency modulation frequency modulation level and modulation distortion from a modulated signal AM or FM Description of FFT The spectrum analyzer is using the Fast Fourier Transform FFT principle For this transform a number of samples are taken with a previously set sample speed The number of samples has to be a power of 2 e g 512 1024 or 2048 With these samples here called FFT block the spectrum is calculated Therefore the FFT places an infinite number of FFT blocks behind each other in the positive and negative direction Each FFT block forms 1 period of the created periodic signal A ili a E Y E LL 3 dl periodic FFT block Perodie t extension extension From the signal obtained like this the spectrum is calculated The FFT calculation results in a number of spectral components which is half the number of samples in the FFT block e g 256 512 1024 These spectral components together form the frequency spectrum of the input signal The spectrum analyzer displays an amplitude spectrum which means that a 2 volt peak peak sine wave is displayed with a 1 volt spectral component Aliasing Like the oscilloscope the spectrum analyzer needs a high enough sampling frequency to avoid aliasing The result of aliasing when us
111. the right button is indicating Invert Off The channel view button For controlling the software offset and the software gain some pre defined settings are available by pressing the chan nel view button These settings are offset 0 and gain 1 using full screen offset 0 5 input sensitivity and gain 0 5 upper half of the screen offset 0 5 input sensitivity and gain 0 5 lower half of the screen offset and gain have the last value set by the user These settings are available by pressing the channel view button Each setting has its own picture on the button The image below displays the above mentioned settings from left to right RE Me The image at the button indicates the current settings Each click on the button will select the next state If the offset or gain are changed by other means and one of the predefined states is obtained the button will go to that state as well otherwise user is displayed The channel view button for channel 1 is found at the left hand side of the display for channel 2 at the right hand side of the display Changing the units of the vertical axis Along the vertical axis normally the voltage of the input signal is projected The unit of measure is then Volt and the numbers along the axis correspond with the size of the input signal The oscilloscope allows you to create another definition of the vertical axis By means of the choice Units of measure from the Chl menu the units of measu
112. the voltmeter the input range or sensitivity can be set through the channels settings dialog The channels setting dialog is called by selecting the Channels option from the Settings menu In this dialog the input sensitivities are available as well as an autoranging setting The Voltmeter 46 DI 770 and WINDAQ Scope Manual To switch on Autoranging for the Voltmeter a special button is available When auto ranging is switched on the but ton caption is Auto otherwise it holds the current set input sensitivity Pressing the right mouse button on this button will bring up a menu with all sensitivities When the input signal is larger than the selected input range is displayed Note When Autoranging is switched on several measurements might be needed to set the input sensitivity properly depending on the input signal Another way to set the sensitivity is by using the keyboard A few keys have been reserved for setting the input sensi tivity of the channels These keys are Increase Ch1 sensitivity Decrease Ch1 sensitivity lt F8 gt Decrease Ch2 sensitivity lt F7 gt Increase Ch2 sensitivity Setting the input coupling The input signal can be coupled directly to the ADC DC or through a capacitor to the ADC AC In the hardware a capacitor is switched into AC or out of DC the signal path In COUPLING DC the complete signal AC DC at the input is passed through In COUPLING AC only the AC component
113. tivity Pressing the right mouse button on this button will bring up a menu with all sensitivities Note When autoranging is switched on several measurements might be needed to set the input sensitivity depend ing on the input signal Another way to set the sensitivity is by using the keyboard A few keys have been reserved for setting the input sensi tivity of the channels These keys are Increase Ch sensitivity Decrease Ch1 sensitivity Increase Ch2 sensitivity Decrease Ch2 sensitivity Setting the signal coupling of a channel The input signal can be coupled directly to the ADC DC or through a capacitor to the ADC AC In the hardware a capacitor is switched into AC or out of DC the signal path In COUPLING DC the complete signal AC DC at the input is passed through In COUPLING AC only the AC component of the input signal is passed through It is then possible to examine e g a 20 mV ripple on a 30 V DC voltage since only the ripple is passed through and the DC voltage not AC voltages with a frequency lower than 4 Hz are not coupled correctly There are three different ways to set the coupling Two ways are by clicking the coupling button or by pressing keys The third way is through the Signal coupling menu The Signal coupling menu is called by enabling the Chl menu and then selecting the Signal coupling menu In this menu the settings Coupling AC and Coupling DC can be found The menu can also be entered by cl
114. to the corresponding bargraph The following explanations expect that the Display settings dialog 1s displayed and active Switching displays on and off A display can be made visible by placing a checkmark in front of the Show display string If a display is turned on while the matching channel is not measured the display will not be showed If all six displays are visible the layout is as following The left hand side displays belong to channel 1 The right hand side displays belong to channel 2 Switching bargraphs on and off Each display has a bargraph that can be switched on or off independently from the displays The bargraphs can be switched on or off by tagging or untagging the Show bargraph option The Voltmeter 48 DI 770 and WINDAQ Scope Manual Processing the measured value The software can process the measured value in 11 different ways By activating the Measurement selector the fol lowing calculations can be set TRUE RMS The true RMS value of the input signal is calculated The true RMS value Root Mean Square is the value of a random voltage corresponding to a DC voltage dissipating the same power in a resistance in the same amount of time So an AC voltage of 1 volt RMS corresponds to a DC voltage of 1 volt Most cheap voltmeters only display when measuring AC voltage the cor rect value when the input signal is a true sine wave and usually in a limited frequency range This instrument always
115. ue of the gain has to be between 0 25 and 4 where values smaller than make the signal appear smaller and values larger than 1 make the signal appear larger To change the software gain by dragging the vertical axis place the mouse pointer over either the upper most or the lower most label of the vertical axis These labels are drawn inverted When the mouse pointer is over one of these labels press the left mouse button and drag the label upwards or downwards thereby enlarging or shrinking the axis and the signal Inverting a channel With the software it is possible to invert the signal of a channel This software invert multiplies all measured values by 1 and adapts the values along the vertical axis accordingly There are three ways to invert a signal by means of a menu by means the keyboard and by pressing the invert button The Invert menu is found in the Chl menu In this menu two choices are available to switch the invert on or off A few keys have been reserved to set the invert lt i gt toggles the invert of channel 1 lt Shift i gt toggles the invert of channel 2 The Oscilloscope 33 DI 770 and WINDAQ Scope Manual In the tool bar for each channel an invert button is found the invert button for Ch1 at the left hand side of the screen for Ch2 at the right hand side of the screen The picture at the button indicates the state of the invert setting The left button of the two buttons below is indicating Invert On
116. ula peak value CREST HA RMS Value peak value is the highest voltage of the input signal with respect to the zero level Frequency The frequency of the input signal is determined Frequencies lower than 0 5 Hz are displayed as 0 Hz The frequency can be determined for one channel at a time If the frequency is deter mined for channel 1 the frequency of channel 2 can t be determined Duty cycle The duty cycle of the input signal is determined The duty cycle indicates how much of a sig nal is low high depending on the duty cycle setting in relation to the periodic time of the sig nal The number is given in percent The Voltmeter 49 DI 770 and WINDAQ Scope Manual Displays the voltage level of the first post sample Note If a frequency or duty cycle measurement is set the voltmeter is slower on all displays because for determina tion of the frequency or duty cycle more measurements have to be done Displaying the calculated value For displaying the measured and calculated values 16 methods are available Activate the Display measured value selector to set the following possibilities gt than HI The value is compared to the high value If the value is higher than the high value then PASS is displayed else LO is displayed lt than LO The value is compared to the low value If the value is lower than the low value then PASS is dis played else HI is displayed gt lt COMP The value is comp
117. ular Displaying channels The spectrum analyzer has several modes to display the two channels To select the measure mode enter the Measure menu and select measure and display only channel 1 measure and display only channel 2 Chl and Ch2 measure channel and channel 2 simultaneously and display the values of both channels When only one channel is measured the controls of the other channel are disabled or removed from the display The Spectrum Analyzer 61 DI 770 and WINDAQ Scope Manual Setting up a channel The two channels of the spectrum analyzer are completely configurable Both channels are identical each has its own menu item in the main menu The possibilities of the vertical axes in the spectrum analyzer are the same as in the oscilloscope so only the differences are discussed here Since the possibilities for both channels are equal channel 1 is explained here Setting the input sensitivity The input sensitivity of a channel determines how large a certain signal will be displayed the lower the full scale value the larger the signal will be displayed It is possible to enable an autoranging function Note The vertical axis in the spectrum analyzer has a range that is twice the input sensitivity This is done because the frequency components of which a signal is built can have a larger amplitude than the input sensitivity So if an input sensitivity of 8 Volt full scale is selected the axis will have values fr
118. upling Of a Channel ui id A A 32 Settine the vertical POSIMOM Ol a Chanel ai A A 33 Masntiyme orr ducine the Vertical AXIS a ica 33 TVET Sa camelias 33 The Chaniiel View DUON tii 34 Chaneins the unitsof the vertical AXIS A visas pide vide a i 34 Mouse Sensitivity for the vertical AXIS 2 io 35 So os IA au ateianl a eine ieeudeeuverosauat 35 Settino TNE Sample te QUCHICY ar ida 35 Serio MetecOrd leneta a ads 35 CUM Che pro CeO ger vallecas 36 Mouse sensitivity pre trigger position adjustment ccccccnccnnnnnnnncccnnnnnnnnnnnnnnnnanonnnnnnnnnnnnnnnnnninannnnnnos 36 Masny fhe horizontal AXIS io 37 Setting the horizontal position of the sigmal S ooooonnnnnnnnnccnnononononncnnnnnonnnonononanonncnncnnnnnnnnnnnnos 37 The record Vie wSCroul Date gaelic AA Aa hinds hive Maden ae ae 37 NNN SS AI sa28 oo O PU Oo II O A acinar tealantaae 38 Sclectin amp te tHe ser SOLIS aii 38 Table of Contents yi DI 770 and WINDAQ Scope Manual Selectine eti ser mode seire tdi 39 Settino the torre a 39 Sica ss AM a PEE E 39 Mia A meets terrae mre rerum ret eure ner ter ncn tan nn nen rer nen Neat Rete DOr 39 There sentis OU E chit Sta cede atenehn tat y Glas ote asii 40 POT OFM INCAS URE me lado ados 40 SOPPAN mea re E ea A lvorassdiencounenentatens 40 Perform Auto disk measure menis ari E e 41 AO SU ide 41 LONAS A E acia in ic cues dea dios ios 42 Pertormine CUTSOL measurements os 42 SW CCAS ON CUES OLS ida 42 Settino Up the cursor measur
119. ure menu In the next menu a number of measurements can be selected that have to be averaged The item 1 measurement will switch off averag ing Averaging can also be switched on or off by pressing the Averaging button rip When averaging is set to e g 20 measurements and the oscilloscope is set to Pause pressing the One shot button will result in taking 20 measurements which are averaged Averaging is reset each time when the setting of the instrument hardware changes sensitivity coupling sampling fre quency record length etc and when the pre defined reset number is reached Note When a number of pre samples is set averaging will have a large effect on the shape of the signal in the pre samples because this part of the measured record changes much Math mode The oscilloscope is equipped with a special Math channel This channel can display the following signals Chl Ch2 Chl Ch2 Ch2 Chl These are display added or subtracted signals This means that the on screen signal sizes are added or subtracted The position and size of the math signal can be controlled by the software offset and software gain of both channels To get a math channel both channels have to be on Selecting a math channel is done by selecting a menu item from the Math menu The Math menu can be found in the main menu or can be called by clicking the math button E Hint When the oscilloscope operates in split screen mode and chl uses the upper half of
120. ussed here Setting up the frequency axis type The frequency axis can be set up in four different modes Linear the frequency axis runs from O to the maximum frequency and has a linear division Logarithmic the frequency axis runs from the minimum frequency to the maximum frequency and has a loga rithmic division Octaves the frequency axis runs from 22 1 Hz to 22 6 kHz and is divided in 10 octaves The center fre quencies the lower limits and the higher limits of the octaves are Each octave 1s displayed with the same width on the display This mode requires that the sampling frequency is about 44 kHz and the record length is at least 1024 spectral components When this display mode is switched on the sampling frequency can no longer be set and the record length can only be set to a few lengths Third octaves the frequency axis runs from 17 54 Hz to 22 6 kHz and is divided in 31 thirds of octaves The center frequencies the lower limits and the higher limits of the octaves are 19 68 Hz 17 54 Hz 22 09 Hz The Spectrum Analyzer 63 DI 770 and WINDAQ Scope Manual 49 6 Hz 55 7 Hz The Spectrum Analyzer 64 DI 770 and WINDAQ Scope Manual Each third octave is displayed with the same width on the display This mode requires that the sampling frequency is about 44 kHz and the record length is at least 4096 spectral components When this display mode is switched on the sampling frequency and the record length can
121. which related settings can be altered When the mouse is placed on an object in an instrument window information about the object is given with fly over hints small rectangles with a few words of text and some text in the hint bar at the bottom of the instrument win dow Program setup Several parts of the program can be set up to your own demands To change those settings press the Setup button in the instrument taskbar The following dialog will appear Program settings Duty cycle Active instruments Day and time FP Instrumenttaskbar always on top E Display colors English gt E Directories A Default text Device H5508 Hardware address LFT1 Instrument resolution 6 bits Calibration date 6 8 97 serial number bar The dialog contains 5 pages with related settings the pages can be selected by clicking the tabs Settings that are made in these pages are saved when the application is closed and restored when the application is started again The positions and sizes of the instrument windows are also saved and restored Instrument taskbar always on top It is possible to let the instrument taskbar appear always on top of the other windows In that case the instrument task bar will always be visible The selection for that is made on the Common page with the Instrument taskbar always on top check box Software 21 DI 770 and WINDAQ Scope Manual Setting display colors The colors of channel
122. y sine triangle square DC white noise user defined locked on spectrum analyzer 0 01 Hz to 2 MHz O 12 Volt max 50 mAmp 0 to 99 O 12 Volt 10 storage 256 Kwords 8 bit 100 MHz 12 bit 50 MHz 14 bit 3 125 MHz 16 bit 195 kHz DC to 50 MHz maximum DI 770 25 25 MHz 40 nsec DI 770 100 100 MHz 10 nsec internal 0 01 external 2 analog 200 mVolt 80 Volt full scale 200 Volt DC AC peak lt 10 kHz 1 MOhm 30 pF AC DC 0 2 1 LSB 1 Hz with 1x probe 0 131060 samples each channel Arbitrary Waveform Generator independent from acquisition system Resolution 14 bit 50 MHz Specifications 7 DI 770 and WINDAQ Scope Manual Sample rate Bandwidth Impedance Coupling Output amplitude Amplitude step DC level Waveforms Symmetry Memory Trigger System System Source Trigger modes Level adjustment Hysteresis adjustment Resolution Pre trigger Post trigger Digital trigger input level Power Requirements Power from USB port Power via extension connector Physical Dimensions Weight Cord length I O Connectors Input Channel 1 Input Channel 2 Output AWG USB Extension connector 50 MHz DC to 2MHz 50 Ohm DC 12 Volt 12 Volt 0 0 1 V range 8192 steps 0 1 0 9 V range 8192 steps 0 9 12 V range 8192 steps 0 12 V in 8192 steps sine triangle square DC noise and user defined 1 99 1 steps 1
123. y spectrum of the input signal This num ber has to be a power of 2 After the FFT calculation a spectrum with half of that number spectral components is obtained This number of spectral components is called the Record length To change the record length two ways are available by means of a menu or by means of function keys To change the record length using the menu enter the Frequency axis menu and select the Record length item Another menu will pop up containing the available record lengths The Frequency axis menu can also be entered by pressing the right mouse button over one of the frequency axis controls or read outs For changing the record length the following function keys are available lt F11 gt Select a shorter record length lt F12 gt Select a longer record length Note Calculating a spectrum is time consuming The time need for calculating a spectrum is strongly dependent on the calculating power of the computer and of the selected record length Setting up the FFT FFT window function To reduce smearing errors See Windowing a windowing function can be selected The Spectrum Analyzer 65 DI 770 and WINDAQ Scope Manual To select a windowing function press the Window button es or select the item FFT window function from the Settings menu A dialog will appear in which the requested window can be selected A graphic display will show effect of the windowing function on the sampled signal

Download Pdf Manuals

Related Search

Related Contents

取扱説明書 - フジ医療器  NGS Domo I  A.S.K. Automatic Strobist Kit®  ラスターパネル・ラスターボード ラスターバーモジュール  Bedienungsanleitung APC P3610_Vers. 1.8  

Copyright © All rights reserved. Failed to retrieve file