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DT VPI™ User's Manual

1. 000005 229 Accessing the Unsecured Data Acquisition UserObjects 240 241 Thermocouple Support 227 Chapter 10 DT VPI provides additional data acquisition functionality that cannot be found in the DT DataAcq menu You can access DT VPI s advanced features in the following ways e By calling advanced functions in a Call Function object e By using or modifying the unsecured versions of the secured data acquisition UserObjects and e By merging the thermocouple UserFunctions and using or modifying them in your own programs Each method is discussed in the following sections 228 Advanced Functionality Calling the Advanced Functions Advanced functionality is accessed using a Call Function object Device C gt Function C gt Call The Call Function object s object menu C gt Select Function command enables you to select from among the advanced data acquisition functions Note You must configure a subsystem object before attempting to select an advanced data acquisition function in a Call Function object Alternatively use an Import Library object to import the library of compiled functions called DIVEE DLL whose definition file is DTVEE VH The following subsections describe the advanced data acquisition functions dtv ConfigSubSys dtv ConfigSubSys enables selection opening and configuration of a subsystem via dialog boxes If ConfigInfo is valid then dtv ConfigSubSys
2. 84 92 Acquiring Data from Multiple Channels 94 Acquiring Analog Data Continuously 06 96 What s Really Going On 00 0c cece 98 States of an A D Channel 0 0 0000 0000000 100 Acquiring a Single Analog Value 00004 101 Acquiring a Burst of Data 0 eee eee eee eee 104 Configuring for Burst Mode 0008 105 Using an External Trigger 00000 107 What s Really Going On 000 e eee eee 108 Acquiring Pre Trigger Data 00 cece eee eee 109 Configuring for Pre Trigger Acquisition 110 Acquiring and Retrieving Pre Trigger and Post Trigger Data seian ee E 8 ae oe elena er tite Reece sas eee 111 Acquiring Data Using a Triggered Scan 06 N2 Changing the Subsystem Configuration 5 117 Contents Handling Acquisition Errors 0 e cece 121 Errors When Writing to File 0048 122 Trapping Errors eese d irran eR Rete ee 122 Sending Data to a Disk File 0 cece eee eee 125 Writing to File Using the To File Object 125 Writing Directly to File 0 0 00 00 000 130 Configuring Each Channel for Writing to a File 133 Configuring Multiple Channels for Writing to a Single Files 62444 sand magii dand nade R EI EER gianna 135 Configuring for Slow Sampling Rates
3. 138 Sending Data Through DDE cece eee eee 139 Optimizing Analog Input senur cece eee eee 142 Chapter 5 Analog Output 000 200 eee eeee 145 Connecting External Devices 0 0 c cece ee eee 147 Configuring for Analog Output 0000048 147 Selecting a Board when More than One Data Acquisition Board Is Installed 0000 cece eee eee 148 Configuring the Channel List 06 149 Selecting an Output Rate 00 eee eee 150 Selecting an Output Range and Type 153 Specifying a Subsystem Handle 06 154 Starting an Analog Output 00 e eee ee eee eee 159 Outputting Analog Data from a Single Channel 156 Outputting Analog Data Continuously 159 What s Really Going On 0 0 ee eee eee 160 States of a D A Channel 0 0 0 0 000 cece eee 162 The Critical Threshold aaua 163 Outputting a Single Analog Value 000000 164 vii Contents Vili Outputting a Burst of Data 0 cece eee eee 166 Configuring for Burst Mode 0008 166 What s Really Going On 0 0 e eee eee 169 Changing the Subsystem Configuration 170 Handling Acquisition Errors 0 cece eee eee 179 Errors When Reading From File 06 175 Trapping EmO
4. AMD Cloth ee ee ee D R D 3 Figure 110 Timing Diagram for a Counter Timer used as aTrigger To Start Acquisition 215 Chapter 8 Using the Counter Timer to Count Events The counter timer counts the number of events on the internal or external source input In most cases you are interested in counting external events as opposed to the board s internal oscillator pulses To count the number of events in an external signal input connect an external signal to SRC1 on the screw terminal panel then connect the ground lead A program using the C T subsystem to count events is shown in Figure 111 BventOccurrences after d seconds Figure 111 A Program Using the Counter Timer To Count Events in an External Input Signal Configuring the C T to Count Events Select the C T Config object and click Configure Set the mode to Count Events See your hardware user manual for more information on the definition of an event Under Clock Source select Internal or External Typically you set the gate source to External events are counted based on the gate specified High Level Low Level Rising Edge Falling Edge For this example the clock source is an external signal of type High Level The appropriate gate input and ground connections were made 216 Using Counters and Timers What s Really Going On When you run this program the C T subsystem begins counting the number of events on the clock source input
5. DATA TRANSLATION UM 16150 C DT VPI User s Manual Version 6 0 Third Edition July 2000 Data Translation Inc 100 Locke Drive Marlboro MA 01752 1192 508 481 3700 www datatranslation com Fax 508 481 8620 E mail info datx com Copyright 1997 1998 2000 by Data Translation Inc Copyright 2000 by Agilent Technologies All rights reserved No part of this publication may be reproduced stored in a retrieval system or transmitted in any form by any means electronic mechanical by photocopying recording or otherwise without the prior written permission of Data Translation Inc Information furnished by Data Translation Inc is believed to be accurate and reliable however no responsibility is assumed by Data Translation Inc for its use nor for any infringements of patents or other rights of third parties which may result from its use No license is granted by implication or otherwise under any patent rights of Data Translation Inc Use duplication or disclosure by the United States Government is subject to restrictions as set forth in subparagraph c 1 ii of the Rights in Technical Data and Computer software clause at 48 C F R 252 227 7013 or in subparagraph c 2 of the Commercial computer Software Registered Rights clause at 48 C F R 52 227 19 as applicable Data Translation Inc 100 Locke Drive Marlboro MA 01752 Data Translation is a registered trademark and
6. Using the example above frequency of 1000 Hz over a time span of 10 ms try a D A Rate setting of 20 000 Hz Assume you want about 100 points per cycle from the Function Generator so for 10 cycles a setting of 1000 points is needed for NumPoints To compute the duration of the output waveform divide the setting for NumPoints by the D A Rate For our example this is lsecond 1000points e 20000samples duration gt second duration 1 20 151 Chapter 5 152 1000points 20000samples lsecond duration Given these settings for the Function Generator object Frequency of 1000 Hz TimeSpan of 10 ms 1000 NumPoints and with the DAC outputting at a sampling frequency of 20000 Hz the duration of the 10 cycle output waveform is 0 5 seconds 1 20 second Because this duration is less than 0 5 seconds the DAC should be configured for burst mode In the D A Advanced Configuration dialog box enable Burst duration See What s Really Going On starting on page 160 to learn about the 0 5 second threshold To compute the frequency of the output waveform itself in cycles per second or Hz divide the D A Rate samples per second by the number of points per cycle which in our example is 100 points per each of 10 cycles 20000samples Tsecond _ 20000samples lcycle _ TW0points Tsecond T00points 7 07 Icycle The frequency of the output wave is 200 Hz If you lower the D A Rate rem
7. ssususrssusnrrr rr rnrn eee 14 Adding an Object to the Work Area 05 14 Moving an Object 0 6 eee eens 15 Selecting the Object Menu 00 0 0 0 ee 15 iii Contents iv Copying an Object 0 0 eee eee 16 Cutting an Object 0 cee cee 17 Pasting an Object 0s 0 ios eeideaeees dies aeeees enuia 18 Changing Object Views 0 0c cece eee eee 18 Changing the Size of an Object 000 19 Changing the Title of an Object 004 20 Understanding Pins and Terminals 00044 22 Connecting ObjectS 60 cece eee ees 23 Adding Data Input Terminals to an Object 23 Deleting Data Input or Output Terminals from an Object 24 Renaming a Terminal asunaren eee eee 24 Understanding Propagation usasse 000 e eee eee 25 Chapter 3 Your First Program 000eeeeeeeee 29 Lesson 1 Create A Simple Program 0 00005 31 Step 1 Add the Objects 00 eee eee eee 31 Step 2 Connect the Objects 2 0 6 06 c eee eee 32 Step 3 Run Your Program 0 6 eee cece eee eee 33 Step 4 Change Object Parameters 06 34 Step 5 Print the Screens 2 i ites ace wteeecesedeces 36 Step 6 Save Your Program 0 6 eee eee eee 36 Lesson 2 Modify Your Simple Program 38 Step 1 Make Some Noise 00 cece eee eee 38 Step 2 Add an Amp
8. Default Button The button in a dialog box that is activated by default if Enter or Return is pressed or the selection is double clicked The default button has a recessed border Glossary Demote To convert from a data type that contains more information to one that contains less information See also Data Type and Promote Detail View The view of a VEE program that shows all the objects and the lines between them Device An instrument attached to or plugged into an HP IB RS 232 GPIO or VXI interface Specific VEE objects such as the Direct I O object send and receive information to a device Dialog Box A secondary window displayed when VEE requires information from you before it can continue For example a dialog box may contain a list of files from which you may choose Digital to Analog Conversion The process of converting digital values to analog voltage values DLL Dynamically Linked Library A collection of functions written in C that can be called from VEE DLLs can be created by experienced C programmers using tools available from Microsoft and Borland DMA Direct Memory Access A method of transferring data from a data acquisition board to memory that circumvents the CPU DMA is much faster than the older polled I O and interrupts methods Some data acquisition boards use two DMA channels use one channel while the other fills with data then switch while other boards can operate with a single DMA cha
9. Note The buffer used to copy and paste VEE objects is not the Windows clipboard Cutting an Object To delete the Function Generator object and save it in a buffer for pasting later perform these steps 1 Select the object 2 Click the Cut button _ The object is deleted from the work area and goes to a buffer for pasting later Other ways to cut an object are as follows e Select the object click the right mouse button to get the object menu and then click Cut e Double click the control bar E of an object in open view Press Ctrl D when the mouse cursor is over the object Each time you use Copy or Cut whatever is in the buffer is overwritten If it is running stop the program before cutting or copying objects 17 Chapter 2 18 Pasting an Object Once an object is in the buffer you can paste the object as many times as you want To paste the object in the buffer onto the work area perform these steps 1 Click the Paste button An outline of the object appears 2 Move the outline to the desired location in the work area 3 Click to place the object Changing Object Views Every VEE object has two views an open view and an icon from which you can choose When first accessed an object by default appears in its open view In the open view all object parameters are visible and you can edit them In icon view the object is minimized much like you can minimize a window in Wind
10. 133 Chapter 4 134 Set the channels to the following rates and gains Channel Rate Gain Write to File Name Burst Burst Hz File Enabled Duration Enabled seconds 10000 1 yes VEE DATA00 DTV yes 5 format 10000 1 no n a yes 5 10000 1 yes VEE DATA02 DTV yes 5 format Figure 74 shows how the dialog box should look when you are done Always use burst mode when writing directly to file so you do not accidentally fill up your hard disk Adkamtid Colgan Test Deve Arado leapt 0 cm ua o oo Figure 74 Configuring the A D Subsystem To Write Data to Single Channel Files Analog Input When this program is run the A D subsystem is configured and data from channels 0 1 and 2 is acquired and stored in the Mixed Data Buffer This data as usual is pulled out and sorted into the data queues which are sized by the burst duration specification At the same time data is written directly to DATAOO DTV and DATA02 DTV respectively Each of these files contains raw unprocessed values and a special file header The file header includes information for the D A subsystem to convert the values into voltages at a later time Configuring Multiple Channels for Writing to a Single File You can opt to save data from all specified channels to a single binary data file This option is appropriate for high channel count applications situations where you want to sample at high sampling rates or you are nea
11. AD Contig o Get Data Panel Tanim I tY Trace Get Data Parel Figure 73 A Program To Write Acquired Data to Disk Files Analog Input Configuring Each Channel for Writing to a File Some applications require the greater precision of data saved ina separate file for each channel Output may be in either VEE binary or ASCII format You can choose one using the VEE or ASCII Format buttons in the Write to File section of the A D Advanced Configuration dialog box If you select VEE format data for each channel is written to a separate file in raw unprocessed format This format is not readable in a word processor but includes a file header with information for DT VPI to decode the binary file If you select ASCII format data for each channel is written to the file as voltage values ASCII format should only be used with slower sampling rates due to the time needed to convert the data to ASCII voltage values while acquiring data Note To write the data for several channels to a single file place an X in the checkbox next to Multi channel File and refer to Configuring Multiple Channels for Writing to a Single File starting on page 135 for information Using the A D Advanced Configuration dialog box you can set up the channel list just as you would normally As you add each channel click the checkbox labeled Enable in the Write to File section In this example the VEE format is selected
12. e Those that change or set the values of certain parameters Like the other data acquisition objects the set and get configuration objects require a subsystem handle as one of the data inputs Table 5 summarizes the configuration objects and their purpose Table 5 Summary of the Get and Set Config Object s Name Description Get and Set Sampling Obtain or specify the sampling rate and gain settings for each channel in a given subsystem Get and Set Clocking Obtain or specify the clocking source and aggregate clock frequency for a given subsystem Get and Set Channel Buffer Size Obtain or specify the buffer size of a given channel s for a given subsystem Get and Set Range Obtain or specify the programmable voltage range for a given subsystem Get and Set Trigger Obtain or specify the trigger sources and or trigger mode for a given subsystem 117 Chapter 4 Table 5 Summary of the Get and Set Config Objects cont Name Description Get and Set Sample Clock Frequency Obtain or specify the channel to channel sample frequency for an internal re trigger and triggered scan of channels Get and Set Channel Filter Obtain or specify the lowpass cutoff frequency for a given channel on a given subsystem Get and Set Data Mode Obtain or specify the data I O management configuration for the given channel s for a given subsystem Get and Set Multi Channel
13. 2017 o Figure 92 Error Raised When Not Enough Data Is Available in Memory Errors When Reading From File When reading data directly from a file and outputting it you want to be sure of the data s integrity Therefore you want to know of any error that occurs immediately whether it be an output error a read error a problem with the file or whatever 175 Chapter 5 176 You can monitor file errors in one of two ways One way is to enable PopUp File Error detection in the Read from File edit box Enabling this feature permits errors to appear immediately in a pop up dialog box This error cannot be trapped The other way is to use the Acq Status object to repeatedly poll the subsystem to determine if file output stopped for any reason Trapping Errors If you wish to trap the errors for other purposes such as logging them for a report you need to add an Error output pin to the data acquisition object However because most data acquisition objects are secured UserObjects you cannot directly add an error terminal as you can to other VEE objects To verify this fact try to select Add Terminal from Put Data Panel s object menu Notice that it is grayed out To add an error output pin to a data acquisition object select the object and put it into a UserObject Edit C gt Create UserObject Then select the UserObject s object menu C gt Add Terminal C gt Error Output The error output pin is usually connect
14. F3 a i Teacel D 1 I Teat r z a d J a t m Di m ILT E Ont Data Pare H Bain Eoia Tira Figure 64 A ProgramTo Change the Output Rate Programmatically When you run this program 500 points one half second at a 1000 Hz sampling rate is acquired by the A D subsystem and then is retrieved by the Get Data Panel object Since that is all the data we need for this example we stop the subsystem Otherwise it would 119 Chapter 4 continue to acquire up to 4 seconds worth of data aetan 4 j B senes z el ewe SBS ae resi L eion Tine iB i GetCots parei re 5 a i nGa Sirpis ise Sangirg EI Fea a Ferre Taki 1 Gab Cots Fai 4 Figure 65 The Same Program Using Acq Status Instead of Delay The Get Sampling and Set Sampling objects used as a pair allow a change to the A D sampling rate Because the Set Sampling object expects the Rate input as a real array containing one value for each channel the new rate is in an real constant object We set this object s property for a one dimensional array of size 1 we are only using one channel which is the sampling rate in hertz When the second Get Data Panel object receives the same data and a handle to a reconfigured A D subsystem it acquires the data using the new sampling rate 120 Analog Input Handling Acquisition Errors In general if an error is raised during acquisition a dialog box appears and your program stops runnin
15. change the sampling rates or gains for all configured channels using objects in the program As inputs this object takes the subsystem s handle the channels a gain for each channel and a sampling rate for each channel It reconfigures the A D subsystem and outputs an updated subsystem handle hSubsys Often the Set Sampling object is placed directly after a Get Sampling object in a program The Get Sampling object finds out the current settings for the channels gains and sampling rates These two objects are often used as a pair so that you can change one aspect of configuration while leaving all other aspects the same Your First Program To add the configuration objects 1 Select the Delete Line button on the tool bar and click the connection between the A D Config object and the Get Data Panel object The connection is deleted 2 Select DT DataAcq gt Get Config C gt Get Sampling and place the Get Sampling object to the right of the A D Config object 3 Select DT DataAcq gt Set Config gt Set Sampling and place the Set Sampling object to the right of the Get Sampling object 4 Connect the objects as shown in Figure 37 At this stage of the example all outputs from the Get Sampling object are connected to the Set Sampling object No configuration aspects are being changed Later you will add a user input slider that will adjust the sampling rate Wiwaha Tiara Aig z z P iee Gal D
16. closed Requested threshold trigger voltage is out of range The threshold trigger voltage must be in the range specified in the A D Hardware Dialog Duplicate filename lt file name gt in list Two channels in the Channel list have the same file name Change one of file names to a unique name The filename lt file name gt is already used The filename added to the list is used for another channel use a unique filename The file lt file name gt already exists The file already exists use a unique file name Bad file name or directory lt file name gt Most likely the filename or directory does not exist Write protect error on file lt file name gt The file is write protected Test file can not be deleted Create no modify network share points are not supported The file cannot be written to a disk drive with no delete privileges The file lt file name gt does not exist The file specified for the D A subsystem to output cannot be found Check the name and path 255 Appendix B 256 2040 2041 2042 2043 2044 2045 2046 2047 2048 2049 2050 Error writing to file lt file name gt Check your drive The disk may be full or there may not be a disk in the floppy drive Error re opening file lt file name gt A system resource problem was encountered Windows may be out of file handles Error reading from file lt file name gt The file could be corrupted or deleted File
17. hSubsys input Int32 subsystem handle Ret Value output Int32 subsystem handle Channel input Int32 channel number Points input Int32 number of samples to acquire Data output Real Array acquired data BufferStart output Real time duration measured from time of acquisition start to time of arrival of first sample in each buffer Useful when using Allow Gaps mode to inform you of how much acquisition time was spent on a gap of data Advanced Functionality dtv GetPreTrigData dtv GetPreTrigData retrieves the specified number of samples from the input subsystem pointed to by hSubsys dtv GetPreTrigData does not loop while waiting for the samples to be available as do the Get Pre Trigger Data Panel and Get Pre Trigger Data Function objects If the requested number of points is not available dtv GetPreTrigData returns a scalar in Data indicating the number of points in the channel s queue If the subsystem is not running and autostart is true dtv GetPreTrigData starts the subsystem If the subsystem is stopped dtv GetPreTrigData posts an error Table 16 dtv GetData Terminal Input or Type Description Output hSubsys input Int32 subsystem handle Ret Value output Int32 subsystem handle Channel input Int32 channel number Points input Int32 number of samples to acquire Data output Real Array acquired data BufferStart output Real time duration measured from time of acquisition st
18. range of your input signal Hardware x pai oo Or ingle Erda Cancal i 4 Help Yoksge Range 0 01 100 r a DMA Cele Tre Figure 45 Indicating an Input Signal Voltage Range Also select either the single ended or differential channel type Your selection should match the actual type of input channel you intend to use Note for pseudo differential wiring configuration select the single ended channel type Note For information on the checkbox labelled Use DMA Data Transfer see page 201 87 Chapter 4 Selecting a Clock and Trigger Source To specify that you are supplying an external clock to be used as the pacer clock for analog to digital conversion click the Timing button from the A D Configuration dialog box Select External from the drop down list under Clock Source Enter the frequency of the external clock signal or your closest estimate in the External Clock Frequency Hz box This frequency must be greater than or equal to the sampling rate for the channels in the Channel List Trigger Source irrar Energia Mode Hems Eartigger Suca Hug Wiican Gust Figure 46 Selecting an External Clock or Trigger Note that a user counter timer can be used to generate an external clock signal See Using the Counter Timer as a Clock starting on page 209 To specify that you are supplying an external trigger to start the pacer clock select External from the
19. using to measure frequency 218 counting events 216 creating a simple program 31 critical threshold 162 163 175 231 CTRIGGER VEE example program 212 247 Cut button 55 71 cutting an object 17 D D A Config object 61 147 DABURST VEE example program 166 247 DACONT VEE example program 153 159 247 DAFILE VEE example program 177 247 DASIMPLE VEE example program 156 247 DASINGLE VEE example program 164 247 data flow 22 25 changing with sequence pins 27 rules 27 data input pins 22 data mode 99 142 161 162 163 183 231 Allow Gaps 131 data output pins 22 data queues 99 161 reading a file as 177 DC outputting 164 DDE receiving data from 180 sending analog data to 139 DDE VEE example program 141 182 247 delay 207 Delay object 199 Delete Line button 38 73 74 deleting an object 17 deleting terminals 24 device drivers 225 differential channels 87 154 digital I O 66 191 configuring 187 connecting external devices 187 Digital In Config object 67 187 Index Digital Out Config object 187 digital to analog conversion 146 DIN VEE example program 189 192 247 DIO VEE example program 190 247 DMA transfer 195 201 documenting your program 226 Done state 100 162 DOUT VEE example program 191 247 dragging an object 15 DT VPI on line help 11 dtv ConfigSubSys 229 dtv GetChannelType 230 dtv GetCriticalThreshold 231 dtv GetData 232 dtv GetEncoding 235 dtv GetFileSize 235 dtv GetFileSiz
20. Click Start on the task bar click Programs select Data Translation DT VPI 6 0 then click DT VPI Help or e Select a DT VPI object in the work area by clicking it Click the right mouse button and then select Help from the object menu If you select DT VPI Help the window shown in Figure 4 appears 11 Chapter 2 Data Acquisition Objects Advanced Functionality Examples Error Codes Glossary Figure 4 Contents of DT VPI Online Help 12 Double click a book icon to see the help topics available The major topics listed in the Contents screen are as follows e Welcome to DT VPI On line Help provides an overview of DT VPI and its relationship to VEE e Data Acquisition Objects describes each of the objects and menus provided with DT VPI They are listed alphabetically and by subsystem e Advanced Functionality describes three ways to tinker with the inner workings of DT VPI e Examples describes the example programs included with DT VPI e Error Codes lists all error codes output from an error terminal and the corresponding message e Glossary provides a brief definition of terms referenced in this manual To quit help and close the help window click the X in the upper right corner of the help window Quitting VEE You can quit VEE by double clicking the VEE icon in the upper left corner of the window or by selecting File O gt Exit However if it is running stop the program f
21. Config object executes first configuring the D A subsystem on the board for burst mode Only enough memory is set aside for the amount of data specified in the burst mode section of the D A Configuration dialog box Meanwhile the Function Generator object is generating 1000 points of a 10 Hz cosine wave It passes the data to the Put Data Panel object When execution passes to it the Put Data Panel object stores the data in memory and automatically starts the D A subsystem Then the board outputs the data on the specified channel Note Because only enough memory is set aside for the specified number of samples or number of seconds of data using burst mode results in more efficient use of memory 169 Chapter 5 170 Changing the Subsystem Configuration The DT DataAcq menu provides objects to check and change the current subsystem configuration programmatically In previous examples you specified the desired configuration using the subsystem configuration object A D Config D A Config Digital In Config or Digital Out Config before you ran the program Two types of configuration objects are available e Those that obtain or get the values of certain parameters for a given subsystem and e Those that change or set the values of certain parameters Like the other data acquisition objects the set and get configuration objects require a subsystem handle as one of the data inputs Table 8 summa
22. D Advanced Configuration dialog box Writing Directly to File If you need to acquire and store data very quickly over 8 or 10 kHz DT VPI provides the capability to pass the data directly to a disk file immediately after it is acquired even before the Get Data Panel object has a chance to retrieve it Data handled this way is stored in raw unprocessed format to save the time needed to convert from raw binary coded values to voltages The binary file contains a special file header which includes all the information necessary to convert the raw data at a later time including the coding method used offset binary or twos complement the resolution and the voltage range 130 Analog Input This file cannot be read into VEE using the From File object unless the necessary steps are taken to convert the raw data You can write data for each channel to a file or you can write data for several channels to a single file The file header for VEE format and VEE multi channel format are described in Appendix C CAUTION It is important to use burst mode when acquiring and writing data directly to disk Since clicking the Stop button on the tool bar does not stop data acquisition the subsystem continues to run and write data to the disk file until the data queues and the Mixed Data Buffer are filled If the system keeps up with the data and the Mixed Data Buffer never fills you could fill your hard disk with data The only way to stop d
23. D subsystem is always ahead of the D A subsystem Note When performing simultaneous analog input and output it is important that both subsystems be configured for the same sampling rate Different sampling rates usually result in an Acquisition Stopped error 2012 199 Chapter 7 Starting Two Subsystems Simultaneously When you run analog or digital input simultaneously with analog output you always have to ensure that at least 0 5 seconds of data is available for the analog output subsystem before it begins to output Therefore it is best to start the analog input subsystem at least 0 5 seconds before the analog output subsystem starts However you can start the Counter Timer subsystem C T with any of the other subsystems simultaneously without cause for worry Recall that the Start Acq object normally takes a single subsystem handle as input Using a Formula object create an array of subsystem handles and pass the array to the Start Acq object as shown in Figure 100 Conigure huh ees i P Formula oT 3 _ e B menn 1 i ag r m Corigung h ub era i 3 ia Figure 100 Starting Two Subsystems Simultaneously 200 Simultaneous A D and D A Sharing DMA Resources For ISA or EISA boards DMA Direct Memory Access is a system resource you should consider when running two subsystems simultaneously Some ISA or EISA boards can provide gap free acquisition using only
24. DT VPI is a trademark of Data Translation Inc All other brand and product names are trademarks or registered trademarks of their respective companies Table of Contents About this Manual 0 0 0c eee eee eee eee xi Whatis DT VPI vs 454 02 e nwheseoedes ad tended seeds ia xi Overview of Data Acquisition susse s 00 eee cece eee xi What Can My Board Do 0 00 xiv Intended Audience 0 0 ccc cnet n eens xv What You WING6d ic fect al adh de a ree eid eet dee bee 4S XV What You Should Learn from this Manual xvi Chapter 1 Installing DT VPI 00 cee eee eens 1 Step 1 Install Your Data Acquisition Board 3 Connecting the Screw Terminal Panel 3 Connecting a Function Generator for Input 4 Connecting an Oscilloscope for Output 4 Step 2 Install the Device Driver 0000000 4 Step 3 Install VEE or os ccc See aGGe enade eei 4 Step 4 Install DT VPL vsncniessnane cedgnndetdnd died day eth due aed donee 5 Chapter 2 Quick Start aaua a 000 cece eee eee 7 The Basics ici oe anes 28 oe ea eaw tessaa re Md eRe Eui 8 Startno VEE iene ac iibiae san ed eats wa E E 8 Getting Help erni si seed Ta etine sees Se eben eas 11 Starting VEE Online Help 004 T Starting DT VPI Online Help 0 11 Quitting VEE ie 8 bce sat kae eee e araa a I a 13 Working with Objects
25. Data Acquisition Board Is Installed If you have more than one data acquisition board installed in your computer a dialog box asks you to specify which board you want to use as shown in Figure 79 Select Device and Subsystem xX ponis Analog Outavi Device Mame ama Sub system to we 1 Figure 79 The Select Device and Subsystem Dialog Box Note This dialog box appears only if you have more than one data acquisition board installed in your system or more than one subsystem of that type exists on the board Select the name of the board you want to use from the Device Name drop down list then select DA Unit 0 from the Subsystem To Use drop down list Click OK 148 Analog Output Note The name of the board is the name assigned to it when its device driver was installed You should select the board that has the capabilities you need for analog output Configuring the Channel List The D A Configuration dialog box shown in Figure 80 is used to build a channel list which specifies which channels you intend to use for analog output and at what sampling rate and gain Figure 80 The D A Configuration Dialog Box 149 Chapter 5 150 Take a moment to consider the external connections you have made Most boards have two DACs channel 0 and channel 1 For each channel you intend to use enter the gain in the Gain edit box and the sampling rate needed in the Rate Hz edit box then
26. Put Data Panel object you must also indicate which channel you have selected in the D A Configuration dialog box Enter this information directly in the user edit box Note Make sure that each Put Data Panel object has a corresponding channel configured in the D A Config object Mismatched channels result in a run time error A Function Generator object provides the data to output It is set to generate 1000 points of a 10 Hz cosine wave over a time span of 1 s Set the Rate in the D A Configuration dialog box to 2000 Hz Click Add or Update and then click OK to close the dialog box Using these settings compute the duration of the generated waveform from the DAC to make sure that the waveform has a duration of at least 0 5 s 1000points Lsecona 1 2000samples 1000points e amnia 5 second lsecond Note Refer to Selecting an Output Rate starting on page 150 for more discussion on setting up the Function Generator object to use with the DACs Since 0 5 seconds of data is the minimum amount of data needed by the Put Data Panel object to start the D A subsystem we have just enough data Run the program by clicking Run Figure 83 shows what the program looks like 157 Chapter 5 Figure 83 Example Program DASIMPLE VEE after It Has Been Run 158 Analog Output Outputting Analog Data Continuously Outputting data continuously is a simple extension of the last program You
27. Type A data type that has an associated shape See also Data Shape and Data Type Container The package that is transmitted over lines and is processed by objects Each container contains data the data type and the data shape Context A level of the work area that can contain other levels of work areas such as nested UserObjects but is independent of them Control Pin An asynchronous input pin that transmits data to the object without waiting for the object s other input pins to contain data For example control pins in VEE are commonly used to clear or autoscale a display Cursor A pointer in an entry field that shows where alphanumeric data will appear when you type information from the keyboard Data Field The field within a transaction specification in which you specify either the expression to be written WRITE transactions or the variable to receive data that is read READ transactions See also Transactions Data Flow The flow of data through and between VEE objects Data flows from left to right through objects but an object does not execute until it has data on all of its data input pins Data is propagated from the data output pin of one object to the data input pin of the next object Data flow is the chief factor that determines the execution of a VEE program Data Input Pin A connection point on the left side of an object that permits data to flow into the object 281 Glossary 282 Data Outp
28. Type Or aiaa O oo a Derental cma Help ohege Flange iono E E Uses DWA Dee Trensler Figure 81 The Hardware Dialog Box 153 Chapter 5 Also select either the single ended or differential output type Your selection should match the actual type of output channel you intend to use Note For information on the checkbox labelled Use DMA Data Transfer see page 201 Specifying a Subsystem Handle When you are done configuring the analog output subsystem click OK A configured subsystem has an identifier called a subsystem handle which is used by other DT VPI objects to identify which subsystem to use All data acquisition objects require a subsystem handle hSubsys as one of the data inputs 154 Analog Output Starting an Analog Output There are several ways to start analog data output and the easiest way is to do nothing By default the D A Config object is set to start analog output automatically when a Put Data Panel or Put Data Function object executes The Put Data Panel or Put Data Function object must have at least 0 5 seconds of data before it executes or it raises an error Another way to start analog output is to use the Start Acq object DT DataAcq O gt Control C gt Start Acq This object is different than the regular Start object in that it starts a subsystem on the data acquisition hardware not the execution of a VEE thread If you do not want analog output to start au
29. Z 705078125 4 27 739975 J 418949539125 3 10048549374 0 751941175 Figure 70 Looking at a Text File of Acquired Data It is easy to read this data back into VEE The example shown in Figure 71 shows a From File object reading in MYFILEO which we know contains 2048 points The data is displayed in a Logging AlphaNumeric object and in an XY Trace object that has been autoscaled Analog Input We know the file has 2048 samples in it Figure 71 A Program To Read Acquired Data from a Disk File Another way to use the To File object even if your sampling rate requirements are not in the 15 kHz or less range is to acquire the data first and then write it to a file The example shown in Figure 72 uses the Acq Status object to determine when acquisition is done When acquisition is done the Get Data Panel object is executed and retrieves 9865 points from the channel s data queue This data is then written to a file MYFILE in binary format The data in this file can also be read using the From File object 129 Chapter 4 a Apama Engh f Lani re apamurani m 4 Done a a Aan 7 gt Dabir Sant Conte Pari Cinna Poo F Cuk E 11 Figure 72 Writing Data to a File after It Is Acquired Because the data is written to disk after it is acquired or post processed you can run this example at a high sampling rate such as 200 kHz Note that you should enable burst mode for 9865 samples in the A
30. accumulate the average FFT results SERIALIO demonstrates serial communication using the computer s COM2 and a dumb terminal SIMULTAN simultaneously inputs and outputs data using the A D and D A subsystems SLOWAD demonstrates how to alter the channel buffer size for slow sampling rates TEMP727 demonstrates the use of the DT727 T expander board to acquire thermocouple data TOFILE demonstrates how to monitor the progress of file output from an A D subsystem THRESH demonstrates how to implement voltage threshold triggering for an A D subsystem TRANSAVG illustrates how to implement a transfer function with averaging e TRIGGER acquires data using a user specified external or internal trigger e TRIGSCAN acquires data using triggered scan mode 249 Appendix A 250 DT VPI Errors DT Open Layers Errors 251 Appendix B 252 DT VPI Errors This appendix contains reference information on the errors that are raised by data acquisition objects For a description of VEE errors refer to your VEE documentation Error Number 0 2000 2001 2002 2003 2005 2006 2007 2008 2009 Description No error DT Open Layers error lt descriptive error string gt Refer to the DT Open Layers errors listed at the end of this appendix Invalid device number passed to routine The hSubsys is invalid Unsupported device type The requested parameter cannot be set because
31. acquisition into your VEE programs using the objects found in the DT DataAcq menu In Lesson 3 you will create a simple program to acquire analog data from an external source such as a function generator and display it Then you will add an Until Break object to acquire continuously Restart VEE if you quit previously If VEE is already running clear the work area by clicking the New button on the tool bar Note If your board does not support continuous data acquisition with gap free data you cannot use the Get Data Panel object when acquiring data Lesson 4 covers how to use the Get Single Value object instead To determine if your board supports continuous data acquisition with gap free data locate the device driver documentation that accompanies your data acquisition hardware InTable 1 Supported Options check the row labelled Continuous Operation Support If there is Yes in the column under the A D subsystem then your board can continuously acquire data using the Get Data Panel object If not then you must use the Get Single Value object instead Step 1 Gather the Equipment Before beginning to write data acquisition programs in VEE make sure you have the equipment needed to perform analog input For this lesson you need e An installed data acquisition board from DataTranslation and its Windows device driver refer to your hardware and device driver documentation 43 Chapter 3 4
32. action you have selected in the VEE window Sequence Input Pin The top pin of an object When connected execution of the object is held off until the pin receives a container 291 Glossary 292 Sequence Output Pin The bottom pin of an object When connected this output pin is activated when the object and all data propagation from that object finishes executing Sequencer An object that controls execution flow through a series of sequence transactions each of which may call a User Function or Compiled Function The sequencer is normally used to perform a series of tests by specifying a series of sequence transactions Sleep An object sleeps during execution when it is waiting for an operation or time interval to complete or for an event to occur A sleeping object will allow other parallel threads to run concurrently Once the event time interval or operation occurs the object will execute allowing execution to continue Step The action of operating one object at a time An arrow points to the object that will operate next Subsystem Functional sections on a data acquisition hardware Each subsystem performs a particular function such as analog input analog output digital input digital output or counter timer functions Prior to use a subsystem must be configured by a subsystem configuration object in VEE Subsystem Configuration Object One of the five data acquisition objects that are used to co
33. and digital output DOUT subsystems This chapter discusses how to control your data acquisition hardware to perform digital input and output Configuration is simple you just specify whether you want to use the DIN subsystem the DOUT subsystem or both Channel lists and sampling rates are not used in digital input and output This chapter also includes many example programs and explanations of using the data acquisition objects provided by DT VPI You will learn how to create programs to e Input digital values repeatedly and e Output digital values repeatedly Digital Input and Output Connecting External Devices Using the screw terminal panel s digital lines also called Bit 0 Bit 1 Bit 2 etc connect your digital input or output device Refer to your hardware user manual for more information on connecting external devices Configuring for Digital I O Typically your data acquisition board has between two and 16 digital lines Check your hardware user manual to find out how many digital lines your board has and how they are organized as ports If they are organized as a single digital port then you can configure the digital lines as either digital input or digital output but not both at the same time If they are organized as more than one port then you can configure one port for digital input and another port for digital output if you wish or all ports as the same type Note To find out the current orga
34. and ending points For example if you have 100 values in one column from row 1 to row 100 the Item is specified as r1cl r100c1 In the TEXT edit box enter the name of the one dimensional array to receive the data You also need to add an output terminal for the data 181 Chapter 5 What s Really Going On When you run this program a conversation with Excel is initiated by the To From DDE object If it can find the server application VEE launches the server application Then the data is read from Excel from row 1 column 1 to row 100 column 1 The data is passed to the Put Data Panel object and then output from the D A subsystem Example on Disk The DDE VEE example program in the Examples Dataacq directory uses Microsoft Excel as the server application 512 samples of data are acquired and written to an Excel file SHEET1 XLS in one column 182 Analog Output Optimizing Analog Output You can optimize digital to analog conversions in DT VPI by doing the following e Use burst mode whenever appropriate e When outputting data continuously use the Allow Gaps data mode when it is not necessary to output every single value For example when outputting an acquired music signal Allow Gaps would not be appropriate but it might be appropriate when outputting data to run a robot arm When a gap of data is encountered by Put Data Panel or Put Data Function the last data element received is repeat
35. board refer to your board and or device driver documentation for more information Specify a post trigger source in the list box next to the Source this setting indicates the trigger that stops pre trigger acquisition and starts the post trigger acquisition Note that when collecting data both before and after a trigger event the operation is often called about trigger acquisition Timing x Clock Source fIntemal z External Clock Frequency H2 Cancel p iE Trigger Source External Pre trigger finter Source Mode Normal Re trigger Source intemal Sample Clock Frequency Hz Multi scan count p 000 1 Figure 60 Specify Pre Trigger and Post Trigger Sources 110 Analog Input Acquiring and Retrieving Pre Trigger and Post Trigger Data When it receives the trigger pulse from the pre trigger source the board begins acquiring pre trigger data When the trigger pulse from the post trigger source occurs the board stops pre trigger acquisition and starts post trigger acquisition When you specify a pre trigger source the file name in the Advanced dialog box for individual or multi channel file output represents the file where the post trigger data is stored A separate file stores the pre trigger data The name of the file that stores the pre trigger data is the same as the post trigger file name but contains the letter P at the end or replacing the eighth character
36. clock instead of the onboard oscillator Figure 107 shows the timing diagram for a counter timer as a clock Modine generale rale Frequency 1000 Hz Pulse type Low boe High Buty cycle 30 OT output FL JL JL IL msee Figure 107 Timing Diagram for a Counter Timer as a Clock for Acquisition 211 Chapter 8 212 Using the Counter Timer as a Trigger The counter timer can be used as a trigger to start analog acquisition or analog output The counter timer subsystem is configured to output a single pulse called a one shot this pulse is then recognized by the A D subsystem as the external trigger to start acquiring data To accomplish this the output from the counter timer for example C T OUT1 on the screw terminal panel must be connected to the A D external trigger input A D EXT TRIG on the screw terminal panel Take a look at the example program CTRIGGER VEE in the Examples Dataacq directory shown in Figure 108 ka pD Cape Di Ddsscp Dyre hinis Eb Bed amp 244 468 Aan TFRs rae T EG E _ y fect o eT Condy r P p Gonia rete 4 snc Ea CT etc ananach d a aD et Sieh Conger Maien H z 7 h SEER a l Figure 108 Example on Disk CTRIGGER VEE Using Counters and Timers Note When it executes the C T Config object initializes the counter timers on any Data Translation data acquisition board The initialization causes a s
37. create a program Objects can be displayed as icons or as open views Object Menu The menu associated with an object that contains features that operate on the object for example moving sizing copying and deleting the object 287 Glossary 288 Open To start an action or begin working with a text data or graphics file When you select Open from VEE a program is loaded into the work area Open View The representation of a VEE object that is more detailed than an icon Within the open view you can modify the operation of the object and change the object s title Operate The action of an object processing data and outputting aresult An object operates when its data and sequence input pins have been activated See Activate Outline Box A box that represents the outer edges of an object or set of objects and indicates where the object s will be placed in the work area Pacer Clock Circuitry on a data acquisition board which sets the pace for analog to digital or digital to analog conversions It consists of a frequency source of 400kHz to 10MHz and a divider network that steps the frequency source down to more usable values Palette A set of colors and fonts that is supplied with VEE and used in your VEE environment Panel Information displayed in the center of the object s open view In a UserObject the panel contains a work area In a For Count object the panel contains an entry field Compare with Pan
38. do one or all of the following e Enable burst mode if you know the number of samples required or the duration over which you want to acquire e Enable Allow Gaps data mode For the D A subsystem the subsystem stops when no more data is available in memory for the D A subsystem to output To prevent this error you can do one or all of the following e Enable burst mode if you know the number of samples to output or the duration over which you want to output e Enable Allow Gaps data mode e Slow the output rate e Reduce processing of the outgoing data in VEE Could not create message processing window VEE could not load necessary libraries Restart Windows The specified subsystem has been allocated by another process The Windows driver for the subsystem is already being used by another application There is insufficient free memory to complete the requested function VEE needs more memory Close down other applications to free memory 253 Appendix B 254 2017 2018 2019 2020 2021 2022 2023 2024 2025 2026 2027 2028 There are no boards installed with the specified subsystem type The installed board does not have the subsystem you are trying to configure An internal resource error has occurred VEE had an error obtaining Windows resources Save your program and reboot Internal DLL error Please note what you were doing and call Data Translation The user pressed cancel during req
39. drop down list under Trigger Source Leave the Mode as Normal Click OK to close the Timing dialog box 88 Analog Input Specifying a Subsystem Handle When you are done configuring the analog input subsystem click OK A configured subsystem has an identifier called a subsystem handle which is used by other DT VPI objects to identify which subsystem on the hardware to use The data acquisition objects need information about what channels gains and sampling rates to use All data acquisition objects require a subsystem handle hSubsys as one of the data inputs To explore the concept of subsystem handle clear the work area and place an A D Config object DT DataAcq A D Config on your work area Double click the output terminal hSubsys to get information about it The information dialog box indicates that no data container has been created on the output terminal hSubsys as shown in Figure 47 Click OK to close the dialog box eS Cirig a l Tirmo palleta mat hiama Piaras Conia remi rion He cipal corina irik EEJ em Figure 47 The Output Terminal on the A D Config Object before It Is Run 89 Chapter 4 Now click Run If asked select the data acquisition board you want to use then click OK in the A D Configuration dialog box to use the default channel list Double click the output terminal on the A D Config object again Now that the analog input subsystem has been configured a subsystem hand
40. errors Maintenance Releases are designated in the hundredths digit of the release designation e g 1 2 2 is a Maintenance Release from 1 2 1 Major Release means a new version of any Product that involves major feature changes Major Releases are designated in the ones digit of the release designation e g 2 0 3 0 etc are Major Releases 2 DATA TRANSLATION S OBLIGATIONS Subject to the terms of the Agreement and this Support Policy Data Translation will provide the following support services Support Services for the Products comprising the Software as they may be used with the Licensed Processors a problem reporting tracing and monitoring by interned electronic mail b telephone support for problem determination verification and resolution or instruction as to work around as applicable on a call back basis during Data Translation s normal weekday business hours of 8 30 a m to 5 p m Eastern Time excluding holidays c one 1 copy of each Maintenance Release for the Products comprising the Software d commercially reasonable efforts to diagnose and resolve defects and errors in the Software and Documentation and e furnishing of the maintenance and technical support described above for the current release and the immediately previous Enhanced Release of the Software Support Services will be delivered in English Enhanced Releases and Major Releases can be purchased by Licensee at a discount of twenty fi
41. file Table 19 dtv GetFileSize Terminal Input or Type Description Output FileName input text pathname to file File Size output Int32 file size bytes 235 Chapter 10 dtv GetMixedBufferSize dtv GetMixedBufferSize retrieves the size in seconds of the internal mixed data buffer Table 20 div GetMixedBufferSize Terminal Input or Type Description Output hSubSys input Int82 subsystem handle hSubSys output Int82 subsystem handle MBSize output Real size in seconds of the mixed data buffer dtv SetMixedBufferSize dtv SetMixedBufferSize sets the size in seconds of the internal mixed data buffer Table 21 dtv SetMixedBufferSize Terminal Inputor Type Description Output MBSize input real size in seconds of the mixed data buffer min 0 5 seconds max 10 seconds hSubSys output Int32 subsystem handle 236 Advanced Functionality dtv GetResolution dtv GetResolution returns the resolution of the subsystem pointed to by hSubsys Table 22 dtv GetResolution Terminal Input or Type Description Output hSubsys input Int32 subsystem handle Ret Value output Int32 subsystem handle Resolution output Int32 number of bits of resolution dtv SetResolution dtv SetResolution sets the resolution of the subsystem pointed to by hSubsys Table 23 dtv SetResolution Termi
42. following results You can reproduce the problem by performing these steps f 277 Appendix D E Mail and Fax Support You can also get technical support by e mailing or faxing the Technical Support Department e E mail You can reach Technical Support at the following address tsupport datx com Ensure that you provide the following minimum information Your name Your company or organization A phone number An email address where you can be reached The hardware software product you need help on A summary of the issue you are experiencing Your contract number if applicable and Your product serial number or purchase date Omitting any of the above information may delay our ability to resolve your issue e Fax Please photocopy and complete the form on page 277 then fax Technical Support at the following number 508 481 8620 Support requests from non contract and out of warranty customers are processed with the same priority as telephone support requests World Wide Web For the latest tips software fixes and other product information you can always access our World Wide Web site free of charge at the following address http www datatranslation com 278 Glossary Glossary This glossary defines several terms used to name or describe VEE and DT VPI features Activate 1 To send a container to a terminal See also Container and Terminal 2 The action that
43. information to the server or wait The server responds by sending data or executing procedures Note See Using Dynamic Data Exchange DDE in the VEE Advanced Techniques or VEE OneLab Advanced Techniques manual Windows applications that support DDE can act as either a client or server As a client VEE programs can initiate a conversation with an application that supports DDE and send or request data from that server The example shown in Figure 77 uses Microsoft Excel as the server application A spreadsheet application is appropriate because it can be used to manipulate the acquired analog data that our program sends to it You need to have Excel installed and in your DOS path already running or launched by an Execute Program PC object 139 Chapter 4 pikadon Ect S p iia ae Tair ne ongu biui in Taid Get Data Pane a 7 hahaa l i a bo iF Figure 77 A Program To Send Acquired Data to Excel through DDE In the To From DDE object I O C gt To From DDE PC by default the Application is Excel and the Topic is Sheet1 an Excel document To fill in the information for the transaction double click the empty horizontal bar below Sheet1 and fill in the dialog box as shown in Figure 78 WHITE PGE TEN frist rig TEST Perr DEFALAT Figure 78 DDE Transaction Settings To Send Acquired Data to Excel Click READ REQUEST and change it to WRITE POKE Click STR
44. integrity Therefore you want to know immediately of any error that occurs whether it is an output error a read error a problem with the file and so on There are two ways to monitor file errors One way is to enable PopUp File Error detection in the Read from File edit box Enabling this feature permits errors to appear immediately in a pop up dialog box This error cannot be trapped The other way is to use the Acq Status object to repeatedly poll the subsystem to determine if file output stopped for any reason Trapping Errors If you wish to trap the errors for other purposes such as logging them for a report you need to add an Error output pin to the data acquisition object However because most data acquisition objects are secured UserObjects you cannot directly add an error terminal as you can to other DT VPI objects To verify this fact try to select Add Terminal from Get Data Panel s object menu Notice it is grayed out To add an error output pin to a data acquisition object select the object and put it into a UserObject Edit gt Create UserObject Then select the User Object s object menu C gt Add Terminal C gt Error Output The error output pin is usually connected to the sequence in pin of a Stop Acq or Close Subsystem object if present For example take a look at the program shown in Figure 67 The A D subsystem is configured to acquire 512 samples in burst mode but the Get Data Panel object has 10000 po
45. lowest value Returns the average of the remaining values Table 29 ThAverage Terminal Input or Type Description Output X input Any Array Result output Any Average of values in array CompensationVolts Computes the compensation voltage for a given temperature for a given thermocouple type Table 30 CompensationVolts Terminal Input or Type Description Output Temp input Real Temperature in degrees Celsius Thermocouple input Text Thermocouple Type must be B E J K R S orT Result output Real Compensation voltage 242 Advanced Functionality VoltsToDegrees Computes the temperature in degrees Celsius for given voltage and compensation voltage values Table 31 VoltsToDegrees Terminal Inputor Type Description Output Voltage input Real Voltage value Compensation input Real Value representing the cold junction Voltage compensation voltage This value is added to Voltage prior to conversion Result output Real Temperature in degrees Celsius 243 Chapter 10 244 A Example Programs Appendix A 246 The following is a summary of the data acquisition example programs These programs are located in the directory Program Files Agilent VEE Pro 6 0 Examples Dataacq or Program Files Agilent VEE OneLab 6 0 Examples Dataacq 727 demonstrates how to acquire data using the DT727 Channel
46. ne es 260 Appendix C File Formats 000eeeeeeee eens 267 Single Channel Format 0 ccc cece eee eens 268 Multi Channel Format 0 000 c cece eee neces 269 Channel Gain List Entries 00 000 ccc cece eens 271 Appendix D Product Support 000 e0seeeeeee 273 General Checklist prcencecenderranerri reipi hecenin 274 Service and Support 0 eee eens 275 Telephone Technical Support 0005 275 E Mail and Fax Support 0 00 e ee eee eee 278 World Wide Web 000 cc cece cnet 278 Glossaty iis ss2sisssteeees che br eeeteteenestaeewoembeed 279 INGOX sect bitters E ERE ENA Bee tee 295 About this Manual What is DT VPI Agilent Technologies and Data Translation formed an alliance to provide the broadest range of solutions for data acquisition and test and measurement under Microsoft Windows Agilent VEE Visual Programming Language solves the performance needs of high channel count and instrument based I O The alliance enabled DataTranslation to create a component called DT VPI to support data acquisition from within the VEE visual programming environment DT VPI is targeted at PC based data acquisition requiring low point count typically under 100 channels The name DT VPI stands for Data Translation s Visual Programming Interface It provides you with a visual interface consisting of VEE objects specifically designed to control data a
47. one DMA channel others need two DMA channels You indicate which channels to use when you install the board in your computer Depending on the subsystem and the data acquisition board DT VPI uses the fewest number of DMA channels possible while still acquiring gap free data However DMA resources are limited by the computer itself Even with two boards in your system you have at most three DMA channels one board can use two DMA channels the other board can use one DMA channel Some ISA boards use two DMA channels for the analog input subsystem Therefore if you want your program to run analog input and analog output simultaneously consider the following recommendations e Disable DMA on the analog output subsystem Click Hardware from the D A Configuration dialog box and uncheck the box next to Use DMA DataTransfer You will not be able to run as fast as you would using DMA data transfer e Use two boards making sure that one board is configured to use only one DMA channel and that it does not use a channel that is already being used by the other board Refer to your device driver documentation for information on configuring your board and driver e If DMA is more important than running the subsystems simultaneously run the two subsystems sequentially executing a Close Subsystem object in between 201 Chapter 7 202 Note Refer to the device driver documentation accompanying your data acquisition ha
48. opens the subsystem indicated by ConfigInfo and loads the stored configuration A call to dtv ConfigSubSys is the initial call to open any subsystem for use with other objects Table 10 dtv ConfigSubSys Terminal Input or Type Description Output Ret Value output Int32 subsystem handle EditConfig input Int32 description ConfigInfo input and Int32 Array description output 229 Chapter 10 dtv GetChannelType dtv GetChannelType gets the current channel type The channel type can be either single ended or differential Table 11 dtv GetChannelType Terminal Input or Type Description Output hSubsys input Int32 subsystem handle Ret Value output Int32 subsystem handle ChannelType output Enum singleended or differential dtv SetChannelType dtv SetChannelType sets the channel type to single ended or differential Table 12 dtv SetChannelType Terminal Inputor Type Description Output hSubsys input Int82 subsystem handle Ret Value output Int32 subsystem handle ChannelType output Enum singleended or differential 230 Advanced Functionality dtv GetCriticalThreshold dtv GetCriticalThreshold gets the current critical threshold value in seconds to Threshold The critical threshold is the minimum amount of data allowed in the Mixed Data Buffer before a channel goes to the Done or Waiting state depending on the d
49. own use later Save your program 1 Click the Save button on the tool bar E In the Save File dialog box that appears type a name such as DA VEE Click Save to close the dialog box 65 Chapter 3 Lesson 6 Digital Input and Output Sometimes you need to gather data from a device that is itself digital Most data acquisition boards from Data Translation provide 16 digital lines which can be grouped into two ports of 8 lines each Each port can be configured for input or output or they can be combined to form a single 16 bit port In Lesson 6 you will create a new program that acquires digital data from a digital device and displays the signal in VEE Restart VEE if you have quit If VEE is already running clear the work area by clicking the New button on the tool bar ml Step 1 Gather the Equipment Before beginning this lesson make sure you have the equipment needed to perform digital input and output For this lesson you need e An installed data acquisition board from DataTranslation and its Windows device driver refer to your hardware and device driver manuals e A screw terminal panel connected to the data acquisition board in your system refer to your screw terminal panel manual e A digital device for input connected to digital port 0 on the screw terminal panel Make sure the device is turned ON 66 Your First Program Step 2 Add the Objects To perform digital input add one obj
50. permit simultaneous analog input A D and analog output D A operations often have separate A D and D A pacer clocks Pacer clocks are made up of a frequency source either an onboard free running oscillator or a user supplied signal and a divider network that steps the frequency source down to more usable values The frequency source is also called the clock s base frequency and determines the granularity or distance between available settings Higher base frequencies offer finer granularity especially at high sampling frequencies For example values for a 400 kHz oscillator are 2 5 us apart those for a 5 MHz oscillator are only 0 2 us apart Dividers typically can be set for any value within an 8 or 16 bit range Some designs also use a binary prescaler before the divider to extend the clock s range Pacer clocks are started by triggers either by a program instruction a software trigger or by an external digital pulse or analog voltage at the board s connector an external trigger External clock frequency sources and external triggers help you synchronize data conversions with offboard events an external trigger can serve as a gate to enable conversions while with each tick the external frequency source starts anew conversion About this Manual Using DT VPI and your plug in data acquisition board analog or digital data can be acquired through external sensors connected to your board Your data acquisition board ha
51. rate 150 outputting analog data 60 outputting data a single analog value 164 a single digital value 191 analog burst 166 303 Index 304 analog data from a single channel 156 continuous analog data 159 overview data acquisition xi data acquisition boards xiv DT VPI xi P pacer clock xii 50 panel view 224 pasting an object 18 PCI bus mastering 195 PCLABFIL VEE example program 248 ping 56 pins 22 data input 22 data output 22 sequence input 22 sequence output pin 22 XEQ 56 Polled I O 195 post trigger acquisition 111 post trigger source 110 PRETRIG VEE example program 248 pre trigger data 109 Print button 36 printing the screen 36 product support 274 propagation 25 PSD VEE example program 248 pulse type 205 pulse width 207 Put Data Function object 155 183 Put Data Panel object 155 174 position in program 156 Put Data Panel objects 61 Put Single Value object 164 191 Q quitting VEE 13 R Ready state 100 161 162 Real Knob object 41 Real Slider object 74 related documents xix renaming terminals 24 resizing an object 19 Run button 33 Running state 100 162 running two subsystems at once 194 running your program 33 41 47 53 58 64 69 76 S sampling rate xii 84 183 configuring for slow 138 requirements for writing to file 125 130 setting for multi channel file output 136 Save button 36 54 58 65 69 77 saving your program 36 49 54 58 65 69 77 screen prin
52. subsystem to any data acquisition object that needs to interact with it A data packet carrying the subsystem handle travels along the connection from the A D Config object to the Get Data Panel object The Get Data Panel object is executed when it receives the subsystem handle on its data input pin It automatically starts the board acquiring When enough data is in memory the Get Data Panel object retrieves some data The exact number of data points it retrieves is specified in the Points edit box Open the Get Data Panel object to see the Points box When it has retrieved as many samples as is specified in the Points edit box in this case 512 the Get Data Panel object outputs an array containing the data on its data output pin You can see the packet traveling along the connection between the Get Data Panel object and the Waveform Time object To see this data click the Line Probe button on the tool bar E and click your mouse on the connection between the two objects 5 When it receives data on its input pin the display object is executed displaying the data Here are the rules of data flow through objects e Data flows from left to right through an object This means that on all objects with data pins the left data pins are inputs and the right data pins are outputs e All of an object s data input pins must be connected Otherwise an error occurs when the program is run An object will not be execut
53. 0 x1401 275 Appendix D 276 If you are located outside the USA call your local distributor The name and telephone number of you nearest distributor are provided in your Data Translation catalog If you are leaving a message to request a support call please include the following information Your name please include proper spelling Your company or organization please include proper spelling A phone number An e mail address where you can be reached The hardware software product you need help on A summary of the issue or question you have Your contract number if applicable and Your product serial number or purchase date Omitting any of the above information may delay our ability to resolve your issue Information Required for Technical Support Name Phone Contract Number Address Data Translation hardware product s serial number configuration Data Translation software SPO number serial number version PC make model operating system version Windows version processor speed RAM hard disk space network number of users disk cache graphics adapter data bus have the following boards and applications installed in my system am encountering the following problem s and have received the following error messages codes have run the board diagnostics with the
54. 1 configuring analog input 81 analog output 147 board selection 82 burst mode 105 166 changing the subsystem 117 170 clock source 88 counter timer as a trigger 213 counter timer as clock 210 counter timer to count events 216 counter timer to measure frequency 219 digital I O 187 external trigger source 107 for slow sampling rates 138 for VEE RunTime 224 hardware filter frequency 85 input channel list 83 input gain value 86 input range and type 87 input sampling rate 84 optimizing 142 183 output channel list 149 output range and type 153 output rate 150 pre trigger acquisition 110 sampling rate 119 to read from a file 178 to write to a file 133 to write to a single file 135 trigger source 88 triggered scan 112 configuring the A D subsystem 45 52 configuring the D A subsystem 62 configuring the digital input port 68 297 Index 298 connecting a function generator 4 a screw terminal panel 3 an oscilloscope 4 digital inputs and outputs 187 objects 23 32 CONTFFT VEE example program 247 continuous acquisition 96 continuous output 159 control bar 18 conventions used xviii copying an object 16 count events 205 Counter object 199 counter timers 204 configuring as a trigger 213 configuring to count events 216 configuring to measure frequency 219 modes 205 optimizing 221 starting with another subsystem 200 using as a clock 209 using as a trigger 212 using to count events 216
55. 2 94 143 Get Multi Channel Mode 118 138 171 Get Range 117 170 Get Sample Clock Frequency 171 Get Sampling 72 117 119 170 173 199 Get Sampling Clock Frequency 118 Get Single Value 51 53 55 67 101 189 Get Trigger 117 170 214 225 iconizing 18 Import Library 229 in Get Config menu 117 170 in Set Config menu 117 170 Integer 51 67 Integer Constant 165 Logging AlphaNumeric 67 93 128 moving 15 Noise Generator 38 40 pasting 18 Put Data Function 155 183 Put Data Panel 61 155 156 174 Put Single Value 164 191 Real Knob 41 Real Slider 74 renaming terminals 24 resizing 19 selecting object menus 15 Set C T Frequency 118 171 Set C T Measure Duration 118 171 Set C T Mode 118 171 Set C T Pulse Width 118 171 Set Channel Buffer Size 117 170 Set Channel Filter 118 171 Set Clocking 117 170 Set Data Mode 118 171 Set Multi Channel Mode 118 171 Set Range 117 170 Set Sample Clock Frequency 171 Set Sampling 72 117 119 170 173 199 Set Sampling Clock Frequency 118 Set Trigger 107 117 170 214 Spectrum Freq 93 Start 27 Start Acq 91 155 174 Stop Acq 119 122 131 162 173 Strip Chart 51 53 93 To File 125 To From DDE 140 180 Until Break 48 51 67 96 Waveform Time 26 31 44 64 93 XY Trace 128 one shot mode 205 on line help DT VPI 11 VEE 11 Open button 70 open view 18 optimizing analog input 142 analog output 183 counter timers 221 oscilloscope 4 output
56. 4 Insure that you have the latest WDM drivers from Data Translation You can find them on our web site www datatranslation com A screw terminal panel connected to the data acquisition board in your system refer to your screw terminal panel documentation A function generator or other signal source connected to A D channel 0 on the screw terminal panel Make sure the signal source is turned ON Step 2 Add the Objects To perform analog input add one object that configures the hardware one object that gathers the data and one object that displays the data 1 Select DT DataAcq gt A D Config and place the A D Config object in the left of the work area Select DT DataAcq C gt Data C gt Get Data Panel and place this object to the right of the A D Config object Select Display gt Waveform Time and place it to the right of the Get Data Panel object Your First Program 4 Connect the objects as shown in Figure 22 weai iTe ll a rro mag _ Chm E haebews i 4 habia Tre JA Aie So He Figure 22 A Simple Analog Input Program Step 3 Configure the A D Subsystem Before you can run the program you must configure the A D subsystem on the data acquisition board A typical data acquisition board has more than one subsystem on it usually a data acquisition board has an analog to digital A D and digital to analog D A subsystem as well as possi
57. 6 66 oe eee eae inne thee eae 176 Reading Data From a Disk File 0 00005 177 Receiving Data From DDE 0 6 eee 180 What s Really Going On 0c ee eee eee 182 Optimizing Analog Output 000 e eee 183 Chapter 6 Digital Input and Output 185 Connecting External Devices 0c e cece 187 Configuring for Digital I O 0 e eee 187 Acquiring a Single Digital Value 004 189 Outputting a Single Digital Value 0 08 191 Chapter 7 Simultaneous A D and D A 193 Hardware Support 6 eee eens 195 Starting Two Subsystems Simultaneously 200 Sharing DMA Resources 6 eee eee 201 Chapter 8 Using Counters and Timers 203 Terminology os sees nde speed ats E 205 Puls Ty pee Gee eee ages ee ieee ed ees 205 Duty Cycle se cceicitiess cies vie eit weeae edr titas 205 Gate TYPES oasia okeee gar Neier demos E i EENE 206 Delay and Pulse Width 0 0 0 cece eee eee 207 Durations ercsi othe dee tere we chad ces eeees deck oes 208 Clock Frequency estet er kadota e A 208 Contents Using the Counter Timer as a Clock 0004 209 Configuring the C T asa Clock 0005 210 What s Really Going On 00 cece eee 211 Using the Counter Timer as a Trigger 06 212 Configuring the C T as
58. DT VPI from Data Translation and a data acquisition board from Data Translation What You ll Need To use DT VPI you need the following Microsoft Windows 95 Windows 98 Windows NT 4 0 or Windows 2000 Pentium 120 MHz or faster processor 20 MB minimum RAM for Windows 95 and Windows 98 48 MB minimum RAM for Windows NT 4 0 or Windows 2000 A monitor that supports a minimum of SVGA 800 by 600 A CD ROM drive A hard disk drive with at least 2 7 MB of free disk space for data acquisition and example programs This space is in addition to the space required to install VEE VEE Pro 6 0 VEE Pro Runtime 6 0 or VEE OneLab 6 0 An installed data acquisition board from DataTranslation An input and or output device connected to the data acquisition board XV About this Manual xvi What You Should Learn from this Manual This manual describes how to install DT VPI on top of VEE Pro development or runtime or VEE OneLab and how to use DT VPI s data acquisition objects to control your data acquisition hardware from Data Translation The data acquisition objects look and behave just like other VEE objects After reading this manual you should understand how to use the data acquisition objects in your VEE programs to acquire process and output analog and digital I O data This manual does not cover other aspects of VEE programming such as the flow of data using the Math objects and creating UserObjects T
59. EE RunTime environment It is written for those users who want to develop a program in VEE e Make all modifications to your program and debug it in the VEE environment Once you have transferred the program to the VEE RunTime environment you cannot change it e Develop the program with a panel view designed for the appropriate window size You may be running VEE on a computer with an Ultra VGA monitor You can use the full capabilities of that monitor in developing the detail view However the panel view must be developed to fit on the display that your run only systems use For example if your run time systems use 640 by 480 pixel VGA monitors the panel view must fit within that space Note Ifit has no panel view your program still runs under VEE RunTime but with a blank screen However Show Panel on Exe cute pop up UserObjects still appears e Leave any data acquisition subsystem configuration objects unconfigured If the system running VEE RunTime has a different data acquisition board or configuration then an error occurs prior to allowing the operator to select a new board To avoid this error leave the subsystem configuration objects unconfigured in the VEE program and require the operator to configure each subsystem configuration object Developing Programs for VEE RunTime The subsystem configuration objects are A D Config D A Config Digital In Config Digital Out Config and C T Config These objects ar
60. ENAME VEE 247 HCHANI VEE 247 HCHAN2 VEE 247 MAGBIN VEE 247 MEASURE VEE 248 MONITOR VEE 241 248 MULTFILE VEE 248 MULITI VEE 95 248 MULTIFILE VEE 138 opening 25 PCLABFIL VEE 248 PRETRIG VEE 248 PSD VEE 248 SERIALIO VEE 248 SIMULTAN VEE 198 248 SLOWAD VEE 248 TEMP727 VEE 241 248 THRESH VEE 248 TOFILE EXE 248 TOFILE VEE 124 TRANSAVG VEE 248 TRIGGER VEE 107 249 TRIGSCAN VEE 115 249 Execute Program PC object 139 external trigger 100 107 configuring C T as 213 using C T as a source 212 F fax support 278 FFT x object 99 file formats multi channel 269 single channel 268 FILENAME VEE example program 247 files formats of 131 133 178 268 269 reading as a data queue 177 reading directly from 177 writing all channels to a single file 133 writing directly to 130 writing each channel to a file 133 writing multiple channels to a single file 135 writing to 125 129 filters 85 flow data 22 25 27 For Count object 55 103 127 135 Formula object 200 frequency 207 external clock 170 frequency measurement 218 From File object 129 177 function generator 4 Function Generator object 14 31 61 151 157 Index G gain 86 Gap Free data mode 99 161 Allow Gaps data mode 163 gates 204 206 gathering equipment 43 50 61 66 70 generate rate mode 205 210 Get C T Frequency object 118 171 Get C T Measure Duration object 118 171 Get C T Mode object 118 171 Get C T Pulse Width object 118 171 G
61. Expansion Panel ADCOLUMN illustrates how to save three channels of A D data as columns to import to programs such as Microsoft Excel ALLCHAN illustrates how to create a multi channel data file using the Get and Set Multi Channel Mode objects as well as using the dtv GetFileSize function Use this example with multfile ADSIMPLE acquires and displays 512 values from the A D subsystem ADBURST acquires and displays a burst of 512 samples from the A D subsystem ADSINGLE acquires a user defined number of values one at a time then builds and displays the resulting waveform ATLABFIL reads data stored by Data Translation s ATLAB library CAL2801 illustrates calibration of a DT2801 Series board CAL2812 illustrates calibration of a DT2812 Series board CAL2821 illustrates calibration of a DT2821 Series board CALCJC illustrates calibration of the cold junction compensation circuit for a DT707 T DT707A T or a DT717 T CNTEVENT counts events using the counter timer subsystem COHERENCE calculates the coherence for two incoming waveforms CONFFT demonstrates continuous acquisition and FFT processing CTRIGGER uses the counter timer subsystem to generate a trigger for the A D subsystem DABURST outputs a burst of 256 samples to the D A subsystem DACONT continuously outputs data to the D A subsystem DAFILE creates a file and outputs it to the D A subsystem DASIMPLE outputs 256 samples to the D A subsystem DAS
62. ING FORMAT and change it to DEFAULT FORMAT 140 Analog Input When working with DDE and using VEE as the client you typically need to find out how the server application expects the item in the conversation to be phrased The Item is a string specifying the starting row and column and the ending row and column to which the data should flow A colon separates the starting and ending points For example if you have 100 values in a one dimensional array you might specify the Item as r1c1 r100c1 which says to put the data in one column from row 1 to row 100 The text n instructs Excel to go to the next row In the TEXT edit box enter the name of the one dimensional array containing the data You also need to add an input terminal for the data When you run this program 512 samples of data are acquired on channel 0 A conversation with Excel is initiated by the To From DDE object If VEE can find the server application VEE launches it Then the data is sent to Excel filling row 1 column 1 to row 100 column 1 To verify that the data was sent open the file Sheet1 Example on Disk If you want to programmatically control the row number then use string concatenation to include the value of the row in the string for the Item In the DDE VEE example program in the Examples Dataacq directory we want to write the data down one column so we use a For Count object to input the row number and increment it by one each t
63. INGLE outputs a user specified value using the D A subsystem DDE illustrates DDE to Excel DIN illustrates continuous digital input DOUT illustrates continuous digital output DIO demonstrates reading from a digital input subsystem and writing to a digital output subsystem DTVFILE reads and displays data from a file containing previously acquired data Illustrates how to parse DT VPI s data acquisition file format EASYPK is a simple peak detection example FILENAME acquires data to a disk file A new file is used for every 512 samples HICHAN1 demonstrates collecting samples using high channel counts HICHAN2 demonstrates the use of Get and Set Configuration objects to programmatically change the channel list MAGBIN illustrates how to find the magnitude of a selected bin from FFT results 247 Appendix A 248 MEASURE measures a frequency using the counter timer subsystem MONITOR acquires and displays current thermocouple temperatures using an A D subsystem and a screw terminal panel with software cold junction compensation MULITFILE illustrates how to read the DT VPI multi channel data file and display results Use this example with allchans MULTI acquires data continuously on four channels PCLABFIL reads data from a file written by Data Translation s PCLAB library PRETRIG demonstrates how to acquire pre trigger data PSD illustrates a power spectral density with averaging using feedback to
64. LTI VEE example in the Examples Dataacq directory shows how to acquire data on multiple channels 95 Chapter 4 Acquiring Analog Data Continuously To accomplish continuous analog data acquisition add a flow object to the program we looked at in the last section This example adds an Until Break object If you know the exact number of samples you want to acquire or the exact duration over which you want to acquire burst mode is more appropriate Burst mode is discussed a little later in this chapter The program looks something like that shown in Figure 53 Lind Break E i AID Config t Get Data Pane L ae a i Get Data Pane E I a O AY Trace GetDeta Parel Figure 53 A ProgramTo Acquire Data Continuously As usual you need to configure the A D Config object setting up your channel list for as many channels as you need For example the configuration for the program above is shown in Figure 54 96 Analog Input Configuration DOTAR G Analog Input 0 xj Edt Canmi D amm Cherel Gan Fists He Co a Daed eee Current Charnel Chenrel Gan Fiste Hel T Cajeulate acua reas Figure 54 Configuration for Continuous Acquisition on Three Channels When you run this program the A D Config object is executed first When it is finished the A D Config object pings its sequence out pin which is connected to the sequence in pin of the Until Break object This connection e
65. Mode Obtain or specify the use of multi channel file output aggregate rate and automatic build of the channel gain list Get and Set C T Mode Obtain or specify the mode gate source gate type and pulse type of a C T subsystem Get and Set C T Frequency Obtain or specify the frequency and duty cycle of a C T subsystem Get and Set C T Pulse Width Obtain or specify the delay and pulse width of a C T subsystem Get and Set C T Measure Duration Obtain or specify the duration over which to measure events For more information on the get and set config objects refer to DT VPI online help Often the get and set config objects are used as a pair Place the get config object so that it executes before the set config object Then connect the outputs from the get config object to the inputs of the set config object except for the one or two parameters you intend to change 118 Analog Input CAUTION Because the set config objects change the configuration of the subsystem it is important that you not reconfigure a running subsystem To avoid this situation stop a running subsystem with a Stop Acq object before the set config object executes For example the program shown in Figure 64 uses the Get Sampling and Set Sampling objects to change the analog input rate the sampling rate The A D Config object is configured to output a 1000 Hz sampling rate on channel 0 Wem a a i uag
66. Put Single Value object Table 9 Hardware Support for Simultaneous A D and D A Analog Input Subsystem Analog Output Subsystem Boards Bus Single Polled Single Polled DMA Master Value 1 0 DMA Value VO DT2801 DT01 EZ DT2812 DT2821 Series DT21 EZ DT2831 Series excluding the DT2839 DT2839 196 Simultaneous A D and D A Table 9 Hardware Support for Simultaneous A D and D A cont Analog Input Subsystem Analog Output Subsystem Boards Bus Single Polled Single Polled DMA Master Value 1 0 DMA Value VO DT31 EZ j DT301 DT302 DT303 DT304 DT321 DT322 4 DT3001 3 DT3003 7 DT3004 DT3005 DT3001 PGL DT3003 PGL DT3010 7 DT3010 32 5 DT3016 7 DT7102 i DT9801 7 DT9802 z DT9803 i f DT9804 4 DT9805 197 Chapter 7 198 SS AID Contig Gat Sam a E DIA Contig pzeen i Notes The DT23 EZ DT24 EZ DT24 EZ PGL DT301 DT303 DT321 DT3002 DT2814 and DT7101 do not have any D A subsystems The DT2815 has no A D subsystem The DT2839 and DT31 EZ feature single channel DMA for the A D subsystem leaving a DMA channel available for the D A subsystem The example program SIMULTAN VEE in the Examples Dataacq directory shown in Figure 99 illustrates how to
67. The Get Single Value object reads the total number of events and the current tally appears on the AlphaNumeric display object The counting continues until you stop the subsystem with a Stop Acq object or reconfigure the subsystem Figure 112 shows the timing diagram for this example abe SO LIPIOE 4 High to Low events counted while gate is high Figure 112 Timing Diagram for a C T UsedTo Count Events 217 Chapter 8 Using the Counter Timer to Measure Frequency To measure the frequency of a TTL signal the counter timer counts the number of events on the internal or external source input over a specified time In most cases you are interested in measuring the frequency of occurrence of external events as opposed to the board s internal oscillator pulses To measure the frequency of events in an external signal input connect an external signal to SRC1 on the screw terminal panel then connect the ground lead Just for fun measure the frequency of your data acquisition board s internal oscillator A program using the C T subsystem to measure the frequency of the internal oscillator looks like that shown in Figure 113 Note that the Get Data Panel object acquires only one point the frequency on channel 0 Get Data Panel J Channel 7 booo aneh Alpheumeric a CiT Contig d hbubaya mal 425M eTe Pomts ooa Daa p Figure 113 A Program Using the Counter Timer To Measure t
68. The requested driver cannot be opened Cannot enumerate specified subsystem capability Error Number 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 Description Dass procedure callback is NULL Invalid enumeration procedure A window handle has not been specified Specified subsystem cannot be cascaded Configuration settings read from SYSTEM INI are invalid Driver could not allocate needed memory Driver could not allocate channel list Driver could not allocate gain list Driver could not allocate filter list No DT Open Layers data acquisition boards are installed DMA cannot be used with multiple channels on this subsystem Invalid pulse type specified for this counter timer mode Gain list set up incorrectly See board s driver documentation Read events issued when subsystem not set for count mode Invalid string pointer Invalid polled I O combination Invalid scan trigger combination Invalid gain Invalid parameters for o DaMeasureFrequency lt 010a gt both the hWnd and the lpfnMeasureProc parameters are NULL Invalid count duration period specified 263 Appendix B 264 Error Number 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 Description Invalid queue specified Invalid retrigger rate specified No command response from hardware Hardware command sequence error Hardware data
69. You need to use the Put Single Value object instead Refer to Outputting Analog Data from a Single Channel starting on page 156 To determine if your board supports continuous output locate the device driver documentation that accompanies your data acquisition hardware Check the row labelled Continuous Operation Support in the Supported Options table If there is Yes in the column under the D A subsystem then your board can continuously output data using the Put Data Panel object Otherwise you must use the Put Single Value object instead 60 Your First Program Step 1 Gather the Equipment Before beginning this lesson make sure you have the equipment needed to perform analog output For this lesson you need An installed data acquisition board from DataTranslation and its Windows device driver refer to your hardware and device driver documentation A screw terminal panel connected to the data acquisition board in your system refer to your screw terminal panel documentation Optional an external analog device to which the program outputs the signal Typically this device is an oscilloscope but depends on your specific needs If one is available connect an oscilloscope to D A channel 0 on the screw terminal panel The program will still run if you do not have an oscilloscope connected Step 2 Add the Objects To perform analog output add an object that generates the data if you are not us
70. a Trigger 06 213 What s Really Going On 00 e ee eee eee 214 Taking it Further An External Trigger to the C T 215 Using the Counter Timer to Count Events 216 Configuring the C T to Count Events 216 What s Really Going On 0 00 e eee e eee 217 Using the Counter Timer to Measure Frequency 218 Configuring the C T to Measure Frequency 219 What s Really Going On 0c ee eee eee 220 Optimizing Counter Timers 0 c cece eee 221 Chapter 9 Developing Programs for VEE RunTime 223 Chapter 10 Advanced Functionality 227 cdtv SetResolution 000 c cece eee eee 237 dtv GetSingleValueEx 0 238 dtv PutSingleValueEx 0 0 cee eee eee 238 dtv GetTriggerThreshold 0000 02 eee 239 dtv SetTriggerThreshold 0 000000 0 008 239 Accessing the Unsecured Data Acquisition UserObjects 240 Thermocouple Support 0 0 0 0 nssr rnrn eee ees 241 THA VGA Be oie cove Seas cod edad ipa Rees ees 242 CompensationVolts 0 60 e cece eee eee eee 242 VoltsTODegTeeS se fesse nopan E EnaA EES 243 Appendix A Example Programs 0 20ee00 245 Contents Appendix B Error Codes 0000e eee cece e ees 251 DT VPI Errors 0 0065 0 ee wae Sansa rre tis eee bee saci ee 252 DT Open Layers Errors 0 0 0 cece cee eee ee eee e
71. accomplish simultaneous A D and D A Let us look at this program in more detail EE o aint a k Get Sampling Hh Set Sampling 1 i Seconds of daa ge Lo J putea Panel h Ti septles camel i 6 Figure 99 Example on Disk SIMULTAN VEE Simultaneous A D and D A In this program the A D subsystem and D A subsystem run continuously and simultaneously but they do not start at the same time First the two subsystems are configured for one channel at a rate of 1000 Hz To make sure that the two subsystems are set to the same rate the D A subsystem is set to run at the rate of the A D subsystem using the Get Sampling and Set Sampling objects Acquisition begins when the Start Acq object executes and four seconds worth of data Delay is set to 4 is acquired and stored before the Get Data Function object retrieves it from memory The delay is used as a precaution ensuring that plenty of data is available for the Put Data Panel object Every time through the loop the Get Data Function object retrieves two seconds worth of data and passes it to the Put Data Panel object Two seconds worth of data equals 2 rate The Put Data Panel object sends the data to memory the data is then output from the board The Counter object logs the iteration and the loop begins again Because Get Data Function retrieves the data before Put Data Panel puts it and the data is continuously being acquired the A
72. acquire data on several channels by scanning through the channel list repeatedly Each scan is triggered by a trigger pulse This example requires a data acquisition board that supports triggered scan with an internal trigger Table 4 lists hardware having A D subsystems that support DT VPI triggered scan mode triggers and clocks 115 Chapter 4 116 Table 4 Hardware Support for Clock andTrigger Combinations for A D Subsystems Board Clock Internal External Internal External Threshold Triggers Triggers Pre Pre Triggers Triggers Triggers DT2821 Internal X Series External X DT2831 Internal XxX X DT3831 External XxX X Series DT2839 Internal X X X External XxX X X DT300 Internal XxX X X Series External XxX X X DT3000 Internal XxX X Series External X X DT3010 Internal X X X X Series External X X X X DT9800 Internal XxX X Series External XxX X Analog Input Changing the Subsystem Configuration The DT DataAcq menu provides objects to check and change the current subsystem configuration programmatically In previous examples you specified the desired configuration using the subsystem configuration object A D Config D A Config Digital In Config or Digital Out Config before you ran the program There are two types of configuration objects e Those that obtain or get the values of certain parameters for a given subsystem and
73. af vee Get Pre Trigger Data Function object getptdatap vee Get Pre Trigger Data Panel object putdataf vee Put Data Function object putdatap vee Put Data Panel object 240 Advanced Functionality Thermocouple Support In addition to advanced function calls DT VPI provides thermocouple support in the form of three UserFunctions These objects can be merged with your own programs you can then use and modify them as needed To merge them into your program select File gt Merge and search for the file LIB THRMOCPL VEE Alternatively select File D gt Merge Library search for the file LIB THRMOCPL VEE and then use Call Function objects to call the functions ThAverage CompensationVolts and VoltstoDegrees Example on Disk The example program MONITOR VEE in the Examples DataAcq directory demonstrates the use of the A D subsystem to collect and display current thermocouple temperatures Example on Disk The example program TEMP727 VEE in the Examples DataAcq directory demonstrates the use of the DT727 T expander board to acquire thermocouple data Using the selected thermocouple channel the program determines which expander channel has the cold junction compensation circuit routed to it It then acquires and calculates the compensation voltage to use in all remaining temperature acquisitions 241 Chapter 10 ThAverage Sorts the input array discarding the highest value and the
74. aman O O O OOO OO OOOO OOO _ Ek Figure 3 The VEE OneLab Window with DT VPI Installed The four major areas of the VEE window are identified e The title bar This is the standard Microsoft Windows title bar which shows the name of the application VEE If you have opened an example program or saved your own program then the program s file name also appears in the title bar You can move the window by dragging the title bar e The menu bar which enables you to select menu items and features e The tool bar which provides handy buttons to Run Stop Pause and Step VEE programs The tool bar also has buttons for New Open Save and Print as well as others 10 e The work area which is the space where you create VEE programs You can move or resize the VEE window using standard Windows techniques Getting Help VEE uses the standard Windows on line help system as does DT VPI Both have their own help file e VEE help includes information on VEE s objects essentially everything except data acquisition objects e DT VPI help includes information on all data acquisition objects and examples on using DT VPI Starting VEE On line Help To get on line help for VEE s objects menus tasks and examples click Help from the main menu then click Contents and Index Starting DT VPI Online Help To access on line help for the data acquisition objects and examples you can do one of the following e
75. annel 173 Chapter 5 174 When the second Put Data Panel object receives the same data and a handle to a reconfigured D A subsystem the Put Data Panel object outputs the data using the new sampling rate Because Automatic Start is selected in the D A Configuration dialog box a Start Acq object is not needed Note Ifyou use Start Acq with Put Data Panel place Start Acq after the Put Data Panel object and be sure to deselect Automatic Start in the D A Configuration dialog box Analog Output Handling Acquisition Errors In general if an error occurs during acquisition a dialog box appears and your program stops running To clear the dialog box click OK Any data in memory at the time is flushed out You need only click Run or the Start object to restart your program For example if a Get Data Panel or Get Data Function object tries to retrieve data for a channel for which there are not enough samples available an error is raised see Figure 92 Similarly if the Put Data Panel or Put Data Function object executes before it has at least 0 5 seconds of data the critical threshold an error is raised In both cases the subsystem is no longer running so a Stop Acq object is not needed The Acquistion Sutpul amp complete tor the channel Thig r hype caused by rocessing thal can not keep up viii he aoquisihon or output rate in Conngdled Function Geile Oije Tite GetahaPr mitre diei Type Call Eror mumber
76. are s device driver 225 Chapter 9 226 e In some cases you may want to secure your program You do not have to secure your program since VEE RunTime shows only the panel view and does not let the operator save the program or modify its functionality However it is possible for the operator to alter what is seen on the screen For example the operator can move objects change their size or remove them from the panel view when the program is not running This has no effect on how the program functions and the changes cannot be saved However you can prevent this entirely if you secure your program before transferring it to the run only environment Note In VEE don t secure your only copy you cannot unse cure a program once it is secured and saved e Document your program VEE provides the Save Documentation menu option to extract information from a program The best source of VEE training for operators is the tutorial which you can access from the help menu In addition you may want to write a short manual for operators of your VEE program Here are some other things to consider when developing your program e Ifit has no panel view your program still runs in VEE RunTime but with a blank screen e You cannot Step your program in VEE RunTime e Breakpoints saved with your program are ignored when running under VEE RunTime 10 Advanced Functionality Calling the Advanced Functions
77. are sampled and the data is stored in the Mixed Data Buffer At this point the data for all three channels is still mixed together 98 Analog Input e In between the execution of other objects the data is pulled out of the Mixed Data Buffer and sorted by channel Each configured channel has its own memory buffer called a data queue Enough memory is set aside for each data queue to hold four seconds of data depending on the channel s sampling rate As much data as can fit in the data queues is pulled out of the Mixed Data Buffer and sorted into the appropriate data queue At the same time more data is acquired and stored in the Mixed Data Buffer so the process is ongoing The goal is to keep the Mixed Data Buffer as empty as possible If however VEE is executing an object that takes a while an FFT x object for example the Mixed Data Buffer might get filled If this happens data acquisition stops on all channels and the sub system is done e When enough data is in a channel s data queue the Get Data Panel object transfers the specified number of samples from memory to VEE The Get Data Panel object passes the data through its output pin to the display object where it is graphed If for some reason the data in a data queue is not removed in time the data queue fills up and begins backing up in the Mixed Data Buffer If this happens that particular channel stops in Gap Free data mode or throws out data in All
78. are filled Step 6 Save Your Program It is a good idea to save your program often You will use this program again in Lesson 7 To save your program follow these steps 1 Click the Save button El 2 Inthe Save File dialog box that appears enter the name AD VEE 3 Click Save to close the dialog box 49 Chapter 3 Lesson 4 Acquire with Get Single Value Acquiring a single value of data is typically used when you are not concerned with a pacer clock for acquisition such as when you are testing the output of a battery the temperature of an oven or some other constant or slowly changing signal In Lesson 4 you will use the Get Single Value object to repeatedly acquire a single value until you click the Stop button If your board does not support continuous data acquisition with gap free data you cannot use the Get Data Panel object when acquiring data so you must use the Get Single Value object instead In this case by repeatedly acquiring a single value you can simulate clocked data acquisition Restart VEE if necessary If VEE is already running clear the work area by clicking the New button on the tool bar i Step 1 Gather the Equipment Before beginning this lesson make sure you have the equipment needed to perform analog input For this lesson you need e An installed data acquisition board from DataTranslation and its Windows device driver refer to your hardware and device driver documentation e A
79. art to time of arrival of first sample in each buffer Useful when using Allow Gaps mode to inform you of how much acquisition time was spent on a gap of data 233 Chapter 10 234 dtv PutData dtv PutData puts the samples in Data to the output subsystem pointed to by hSubsys on the specified channel If the subsystem is not running and autostart is true dtv PutData starts the subsystem dtv PutData posts an error if the subsystem is stopped or if the data queue is full and the subsystem is not yet running PutDone contains non zero if enough room was available on the data queue for the samples and contains zero if not enough room was available on the data queue Table 17 dtv PutData Terminal Input or Type Description Output hSubsys input Int32 subsystem handle Ret Value output Int32 subsystem handle Channel input Int32 channel number Data input Real Array data to output PutDone output Int32 status Advanced Functionality dtv GetEncoding dtv GetEncoding returns the type of data encoding used when converting from analog to digital or digital to analog Table 18 dtv GetEncoding Terminal Input or Type Description Output hSubsys input Int32 subsystem handle Ret Value output Int32 subsystem handle Resolution output Int32 encoding O binary non 0 twos complement dtv GetFileSize dtv GetFileSize returns the size of any specified
80. as underrun 2007 or trigger 2006 error occurred 4 Driver underrun error 2081 occurred The data queue was not able to send data to the Mixed Data Buffer fast enough because an object was executing too long Either change your program or raise the critical threshold 162 Analog Output The Critical Threshold When a channel is configured for Gap Free data mode if at any time there is less than 0 5 seconds of data for that channel in the Mixed Data Buffer that channel goes to the Done state Similarly when a channel is configured for Allow Gaps data mode and less than 0 5 seconds of data is available for that channel in the Mixed Data Buffer DT VPI pads the data with up to 0 5 seconds worth and that channel goes to the Waiting state The value of 0 5 seconds is called the critical threshold You can change this value by calling the function dtv SetCriticalThreshold See Chapter 10 Advanced Functionality in this manual 163 Chapter 5 Outputting a Single Analog Value Outputting a single value of analog data is typically used when you are not concerned with a pacer clock The Put Single Value object is used to output a single value The DASINGLE VEE example program in the Examples Dataacq directory shown in Figure 87 is a typical program using the Put Single Value object TWA Corg aj antigure Raub eys io Figure 87 Example on Disk DASINGLE VEE As usual the D A Config object conf
81. ata Translation s then current fee schedule as additional Licensed Processors are added Support Fees do not include travel and living expenses or expenses for installation training file conversion costs optional products and services directories shipping charges or the cost of any recommended hardware third party software or third party software maintenance fees or operating system upgrade 7 WARRANTY LIMITATION EXCEPT AS EXPRESSLY STATED IN THIS SUPPORT POLICY THERE ARE NO EXPRESS OR IMPLIED WARRANTIES WITH RESPECT TO THE SUPPORT SERVICES PROVIDED HEREUNDER INCLUDING THE FIXING OF ERRORS THAT MAY BE CONTAINED IN THE APPLICABLE DATA TRANSLATION SOFTWARE INCLUDING BUT NOT LIMITED TO IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE THE WARRANTIES AND REMEDIES SET FORTH IN THIS SUPPORT POLICY ARE EXCLUSIVE AND ARE IN LIEU OF ALL OTHER WARRANTIES WHETHER ORAL OR WRITTEN EXPRESS OR IMPLIED 8 GENERAL PROVISIONS Upon the election by Licensee to obtain Support Services the terms of this Support Policy shall be governed by and are made a part of the Agreement
82. ata acquisition objects Example on Disk The TOFILE VEE example program in the Examples Dataacq directory demonstrates how to monitor the progress of file output from the A D subsystem and handles acquisition errors Analog Input Sending Data to a Disk File There are two methods to send acquired data to disk One way is to use the VEE To File object I O C gt To D File In this case the data is written after converting it to voltage values and the program can run only as fast as the To File object can run The other way is to send the data directly to disk immediately after acquisition circumventing having VEE write to the file In this case your program can sample at much higher sampling rates with gap free data These two methods are described in the following subsections Writing to File Using the To File Object Writing data to disk with the To File object is the easiest method because you can read the data back using the From File object without having to handle conversions or read a header However to use the To File object your sampling rate requirements must be under 15 kHz when writing binary files or under 8 kHz when writing text files The actual sampling rate threshold is system and board dependent The example shown in Figure 68 shows how to write acquired data to a text file using a To File object for each channel 125 Chapter 4 L For Court ra 5 Chet Data Parei To File Chan
83. ata acquisition is to reconfigure the subsystem or execute a Stop Acq object However by using burst mode you specify the exact amount of data you want and thus the size of the file A warning is raised if you have also chosen Allow Gaps data mode that your disk may become filled If you do not plan on using burst mode when writing data to disk be sure to use a Stop Acq object in your program Example on Disk The DTVFILE VEE example program in or Examples Dataacq directory illustrates how to read a file containing raw unprocessed data and convert it using VEE objects and the information found in the file header The TOFILE VEE example program in the Examples Dataacq directory demonstrates writing data to disk and monitoring for errors 131 Chapter 4 132 You may want to enable PopUp File Error detection in the Write to File edit box Enabling this feature permits errors to appear immediately without having to use the Acq Status object to repeatedly poll the subsystem to determine if file output stopped In the example shown in Figure 73 we will look at writing data directly to disk files without using the To File object We will set it up to acquire data on channels 0 1 and 2 write the data from channels 0 and 2 to disk files and display only the data from channel 0 Use the program we created in the section Acquiring Analog Data Continuously starting on page 96 Lind Break
84. ata mode Table 13 dtv GetCriticalThreshold Terminal Input or Type Description Output hSubsys input Int82 subsystem handle Ret Value output Int32 subsystem handle Threshold output Real the current threshold value in seconds dtv SetCriticalThreshold dtv SetCriticalThreshold sets the critical threshold value in seconds to Threshold The critical threshold is the minimum amount of data allowed in the Mixed Data Buffer before a channel goes to the Done or Waiting state depending on the data mode Table 14 dtv SetCriticalThreshold Terminal Input or Type Description Output hSubsys input Int32 subsystem handle Ret Value output Int32 subsystem handle Threshold input Real the new threshold value in seconds 231 Chapter 10 232 dtv GetData dtv GetData retrieves the specified number of samples from the input subsystem pointed to by hSubsys dtv GetData does not loop while waiting for the samples to be available as do the Get Data Panel and Get Data Function objects If the requested number of points is not available dtv SetData returns a scalar in Data indicating the number of points in the channel s queue If the subsystem is not running and autostart is true dtv GetData starts the subsystem If the subsystem is stopped dtv GetData posts an error Table 15 dtv GetData Terminal Input or Type Description Output
85. ate Paral i Tatai Figure 37 Adding Configuration Objects 73 Chapter 3 5 Just to make sure everything is still working run your program again The output should look the same as that shown in Figure 37 Step 4 Add User Input At this point you are ready to add the user input object 1 Select the Delete Line button on the tool bar and click the lowest connection the fourth connection from the top between the Get Sampling object and the Set Sampling object This connection is for the sampling rate To verify this open the Set Sampling object by double clicking it and notice the label Rates on the lowest data input pin see Figure 38 The object expects a one dimensional array of sampling rates one for each configured channel In this lesson we are using only one channel so we are going to create a one dimensional array containing one value the new sampling rate Set Sampling i Subas bele Function Name i Channels l Fa hSubsys iani ary Sesamping i Rahe Figure 38 The Set Sampling Object 2 Select Data C gt Continuous C gt Real 64 Slider and place the Real Slider object below the A D Config object 3 Change the lower limit to 200 and the upper limit to 5000 These value are in Hz 74 Your First Program 10 11 It is necessary to edit the limits on the Real Slider object the lower one especially because the value output from the Real Slider object is go
86. ates your board can continuously acquire data using the Get Data Panel object If your board does not support continuous operations you must use the Get Single Value object Suppose you were testing the output of a battery the temperature of an oven or some other constant or slowly changing signal Acquiring a single value is a simple and appropriate method for these situations Figure 56 shows a typical program using Get Single Value 101 Chapter 4 aoco H oesngevaue T Strip Chart Figure 56 A Program Using Get Single Value As usual the A D Config object configures the analog input subsystem on the data acquisition hardware However the Get Single Value object does not refer to the channel list defined in the A D Configuration dialog box You need only specify the channel number as an input to the Get Single Value object usually in the form of an Int 32 object The subsystem handle is passed to a Get Single Value object In addition to the subsystem handle the Get Single Value object needs to know which channel to access An Int 32 object provides this information When you run the program the Get Single Value object immediately acquires one value of the analog signal on the specified channel using the appropriate gain automatically It passes the value to the display object Notes The Get Single Value object uses the hSubsys from the A D Config object but does not use the channel list The Int 32 object pass
87. ation 117 170 closing 142 configuring A D 81 configuring for VEE RunTime 224 counter timer 200 running two simultaneously 194 starting two simultaneously 200 subsystem handle 89 154 subsystems xiii support 275 e mail 278 fax 278 telephone 275 World Wide Web 278 system requirements xv T technical support 275 e mail 278 fax 278 telephone 275 World Wide Web 278 telephone support 275 305 Index 306 TEMP727 VEE example program 241 248 temperature measurements 241 terminal area 40 terminal labels 22 terminals 22 adding 23 deleting 24 renaming 24 ThAverage 242 thermocouple support 241 thermocouple UserFunctions 228 thread 99 161 THRESH VEE example program 248 title bar 10 titles changing 20 To File object 125 To From DDE object 140 180 TOFILE VEE example program 124 248 tool bar 10 TRANSAVG VEE example program 248 trapping errors 122 176 trigger configuring 88 external 107 source 170 threshold 239 TRIGGER VEE example program 249 TRIGGER VEE object 107 triggered scan 112 triggers xii TRIGSCAN VEE example program 115 249 TTL signal 107 U Until Break object 48 51 67 96 V VEE installing 4 quitting 13 starting 8 starting DT VPI on line help 11 starting VEE on line help 11 VEE binary file format 133 178 multi channel 269 single channel 268 VEE RunTime 224 VEE IO file 225 veedoc utility 226 Volts vs Time graph 93 VoltsToDegrees 243 W Waiting state 162 Waveform Time ob
88. ator and place the Noise Generator object below the Function Generator object Select Device C gt Formula and place it between the Function Generator and Waveform Time object Click your right mouse button and select AddTermina Cata Input Delete the current formula and replace it with a b Connect the objects as shown in Figure 17 Your First Program 1 hens Senecea la 4 l Fatada a te Angituds gt Li fi 7 ba Time Gao iin Aba ht t Pc is Mam Poi ice oll p i 3 Tihi Figure 17 Adding a Noise Generator to the Program 9 Run the program 10 Click Auto Scale on the Waveform Time object The output is shown in Figure 18 Figure 18 A Sine Wave with Added Noise 39 Chapter 3 Step 2 Add an Amplitude Input Now add an amplitude input for the Noise Generator object 1 Click the Noise Generator object to select it A shadow appears behind the object when it is selected 2 Position the mouse pointer in the terminal area at the left side of the Noise Generator object The terminal area is the sunken area to the left of the words Amplitude Time Span and Num Points 3 Press Ci CA 4 A dialog box asks you to select an input to add as shown in Figure 19 Tim Span Huri Points Figure 19 Adding an Amplitude Input to the Noise Generator 5 Select Amplitude by clicking OK An amplitude input terminal appears Not
89. ave difficulty using DT VPI Data Translation s Technical Support Department is available to provide prompt technical assistance Support upgrades technical information and software are also available All customers can always obtain the support needed The first 90 days are complimentary as part of the product s original warranty to help you get your system running Customers who call outside of this time frame can either purchase a support contract or pay a nominal fee charged on a per incident basis For priority support purchase a support contract Support contracts guarantee prompt response and are very affordable contact your local sales office for details Refer to the Data Translation Support Policy located at the end of this manual for a list of services included and excluded in our standard support offering Telephone Technical Support Telephone support is normally reserved for original warranty and support contract customers Support requests from non contract or out of warranty customers are processed after requests from original warranty and support contract customers For the most efficient service please complete the form on page 277 and be at your computer when you call for technical support This information helps to identify specific system and configuration related problems and to replicate the problem in house if necessary You can reach the Technical Support Department by calling 508 481 370
90. bly a Counter Timer C T subsystem digital input DIN subsystem and digital output DOUT subsystem In this lesson we will configure the A D subsystem which performs the analog data acquisition from the external signal source converting it to digital form for use by VEE 1 Click the Configure button on the A D Config object The A D Configuration dialog box appears as shown in Figure 23 45 Chapter 3 46 Figure 23 Configuring the A D Subsystem Note If you have more than one data acquisition board installed or more than one instance of that board a dialog box asks you to indicate which board to use You can access only one board at a time The A D Configuration dialog box enables you to specify which channels you wish to use for data acquisition and the sampling rate and gain for each The default configuration in the dialog box specifies that channel 0 is sampled at a rate of 1000 Hz samples per second and at a gain of 1 These settings are sufficient for our example Your First Program 2 Click OK to close the dialog box and to configure the A D subsystem with these settings Your program is ready to run Make one last check to be sure your equipment is correctly connected and turned on Step 4 Run To run your program perform these steps 1 Set the external function generator to output a waveform a sine waveform is fine at a frequency of 100 Hz We configured the A D
91. cely at a frequency of 100 Hz Run the program The output is displayed in the Strip Chart object as shown in Figure 27 53 Chapter 3 Bien See KAN Figure 27 Output when Acquiring a Single Value at a Time 4 Stop the program by clicking the Stop button Ej Step 5 Save Your Program Save your program 1 Click the Save button lE 2 Inthe Save File dialog box that appears type a name such as SINGLE VEE 3 Click Save to close the dialog box 54 Your First Program Step 6 Collect the Data Now we will modify the program collect the data into an array and associate the values with time Because single value acquisition is not clocked by the analog input subsystem s pacer clock values are acquired at imprecise intervals You have no way of knowing how much time elapsed between data samples therefore it is not a very accurate way of sampling data When working with signals that change slowly over time such as the temperature of an oven the fact that the data is not clocked may not impact your results However you can approach an accurate sampling of the data by associating each value with a constant time interval Doing this transforms the data into waveform format A waveform is needed for some display types the Waveform Time object for example as well as some of the analysis objects To collect the data and associate it with time 1 Select the Strip Chart object and delete it by c
92. ch is determined by how the data input and output pins of the objects are connected To understand how the data flows in a VEE program perform these steps 1 Open an example program To do this select Help C gt Open Example double click the DataAcq folder then double click the program ADSIMPLE VEE If you do not have a signal source connected then select a program in a different folder Click the Show Data Flow button on the tool bar 4 If this icon is not present then you are in panel view Switch to detail view by clicking E Run the program click watching for the small square traveling along the connections between the objects The square represents a packet of data 25 Chapter 2 26 To see the order in which the objects execute perform these steps 1 Click the Show Execution Flow button on the tool bar i Run the program click J When an object executes a border blinks around the object for a short time In the ADSIMPLE VEE program the data and execution flows like this First the A D Config object is executed If you are using hardware the A D Config object configures the hardware to sample data at a specified rate on a specified channel If you are using Simple Driver the configuration is simulated When it is done executing the A D Config object outputs a subsystem handle on its data output pin The subsystem handle hSubsys identifies the current configuration of the A D
93. click Add The channel number gain and associated rate are added to the channel list in the Current Channels box If you need to edit one of the channels click on the entry in the Current Channels box the information for that channel appears in the Edit Channels box The Calculate Actual Rates checkbox refers to the actual rates that the analog output subsystem can achieve When this box is checked the Current Channels box reflects the actual sampling rates To view the sampling rate that you originally entered select the channel in the Current Channels box the original rate for the channel is displayed in the Edit Channel box By default the D A Configuration dialog box shows channel 0 in the channel list You can add as many channels to the channel list as your board can accommodate and you can remove all but one channel Your channel list is always sorted by channel number starting with the lowest number You should note that when you run the program DT VPI outputs data on the channels in the order that they appear in the channel list Selecting an Output Rate An output rate is required for analog output except for single value output which is not clocked The output rate is used to reconstruct an analog signal from the data values If you think of the data as the y values on an X and Y axes graph you need the x values The output rate in terms of samples per second specifies how far apart to graph the y values along an x a
94. click Configure Because you intend to output a burst of data click Advanced The D A Configuration dialog box enlarges to show advanced features one of which is burst mode 166 Analog Output Using the D A Advanced Configuration dialog box you can set up the channel list just as you would normally For this example we intend to use channel 0 only Click the entry for channel 0 in the Current Channels section Select the checkbox labeled Enable in the Burst Duration section and the radio button next to Samples Channel Rate Hz Gain Burst Mode Samples Enabled 0 2000 1 yes 1000 Because the Function Generator object outputs 1000 points in 1 second we need the D A subsystem to output at a rate of 2000 samples per second or 2000 Hz Because the Function Generator is generating 1000 points enter 1000 in the edit box next to Samples You could also type in 1 and select Seconds Click Update Note Refer to Selecting an Output Rate starting on page 150 for more discussion on setting up the Function Generator object to use with the DACs The dialog box should look like that shown in Figure 89 when you are done 167 Chapter 5 fahyarced Cordiquealion Tat Derer 7 Analny Input 0 Figure 89 Configuring the D A SubsystemTo Output Data in Burst Mode Click OK to close the dialog box The program is ready to run 168 Analog Output What s Really Going On When you run this example the D A
95. counter timer subsystem starts automatically and counting begins The counting lasts for the time specified in the Duration secs edit box The result is output from the Get Data Panel object when the specified duration elapses The result is in the form of a one dimensional array of size 1 Figure 114 shows the timing diagram for this example GT mtp ft JL ILI LI A pA rath og 5 Low boe High events Frequency number of events over evration Figure 114 Timing Diagram for a C T UsedTo Measure the Frequency of Occurrence 220 Using Counters and Timers Optimizing Counter Timers When you set the counter timer subsystem to output a one shot pulse you specify certain values for the delay and pulse width The data acquisition hardware accommodates your settings as closely as possible The following algorithm is used by the hardware to calculate the actual delay and pulse width 1 a frequency period Set the parameters as follows 1 Set T Delay PulseWidth 2 Read the actual value of T from the board Delay actualT 3 Set DutyCycle 1 4 Read the actual value of DutyCycle from the board 5 Set PulseWidth actualDutyCycle actualT 6 Set Delay actualT PulseWidth 221 Chapter 8 222 9 Developing Programs for VEE RunTime Chapter 9 224 This chapter provides some tips for using VEE and DT VPI to develop data acquisition programs to run in the V
96. cquisition hardware from Data Translation Together DT VPI and VEE offer a spectrum of solutions for many applications This manual describes how to use DT VPI with VEE Overview of Data Acquisition When you think of data acquisition you typically think of acquiring analog data from some sort of external sensor or measuring device such as a strain gauge thermocouple microphone or pressure transducer The data you are interested in could be a single value a series of single values you want to obtain at timed intervals or a continuous stream of data In the latter case the data may be coming in too fast to acquire all of it so you would like to take a representative sample of the data a snapshot in time if you will Using an onboard analog to digital converter ADC your data acquisition board obtains an accurate representation or sample of About this Manual xii data Every so often hundreds or thousands of times a second a value of analog data is recorded The frequency at which a value is recorded is called the sampling rate expressed in samples per second or sampling frequency expressed in hertz The sampling process is called analog to digital conversion or A D conversion To perform multiple conversions automatically at precisely defined time intervals most data acquisition boards from DataTranslation are equipped with one or more pacer clocks A pacer clock typically starts all conversions Boards that
97. ct comprising the Software Support Services will begin on the later of the date the Software warranty granted in the Agreement expires or the date of Licensee s election to obtain Support Services and will apply to such Product for an initial term of one 1 year unless an alternative commencement date is identified in the Support Order Form The initial term will automatically be extended for additional terms of one 1 year unless Support Services are terminated at the expiration of the initial term or any additional term by either party upon thirty 30 days prior written notice to the other party 5 2 Default If Licensee is in default of its obligations under the Agreement except for Licensee s obligation to maintain valid licenses for the Software in which case termination is immediate and such default continues for thirty 30 days following receipt of written notice from Data Translation Data Translation may in addition to any other remedies it may have terminate the Support Services 6 CHARGES TAXES AND PAYMENTS 6 1 Payment The Support Fee in respect of the initial term and as adjusted pursuant to Section 5 2 in respect of additional terms is payable in full prior to the commencement of the initial term or any additional term as applicable 6 2 Changes From Term to Term The Support Fee and the terms and conditions of this Support Policy may be subject to change effective at the end of the initial term or any ad
98. d in Lesson 3 to add the capability of changing the sampling rate by using objects in the program The objects found in the Set Config submenu are handy for changing one aspect of a subsystem s configuration while keeping all other aspects the same Restart VEE if needed Open the program AD VEE you created in Lesson 3 by clicking the Open button on the tool bar l In the Open File dialog box navigate to the directory MY DOCUMENTS VEE programs and double click the file AD VEE Note If your board does not support continuous data acquisition you cannot do this lesson as written Lesson 4 covers how to use the Get Single Value object instead of the Get Data Panel object To determine if your board supports continuous data acquisition refer to page 43 Step 1 Gather the Equipment Before beginning to write data acquisition programs in VEE make sure you have the equipment needed to perform analog input For this lesson you need e An installed data acquisition board from DataTranslation and its Windows device driver refer to your hardware and device driver documentation 70 Your First Program e A screw terminal panel connected to the data acquisition board in your system refer to your screw terminal panel documentation A function generator or other signal source connected to A D channel 0 on the screw terminal panel Make sure the signal source is turned ON Step 2 Modify the Program We will att
99. d normally As you add each channel click the checkbox labeled Enable in the Read from File section Set the channels to the following rates and gains Channel Rate Hz Gain Read from File File Name Enabled 0 10000 1 yes data00 dtv 178 Analog Output When this program is run the D A subsystem is configured The program collects information from the user such as the resolution and encoding of the board the range channel rate number of points and the name of the file to create The UserObject Create the file creates the file on disk containing the special file header and raw data ready to be output to the D A subsystem The Set Data Mode object essentially finishes the configuration that the D A Config object started When the Start Acq object is executed the D A subsystem reads the file and outputs the data directly and quickly If your board supports Gap Free data with single DMA you can continuously output a file of data to a DAC Configure the DAC for Allow Gaps data mode and enable Read from File 179 Chapter 5 180 Receiving Data From DDE Dynamic Data Exchange or DDE defines a message based protocol for communication between Windows applications The communication takes place between a DDE client and DDE server The DDE client in this case VEE requests a conversation with the DDE server about a certain topic The client can then request information or services from the server send information to th
100. d when subsystem wasn t running Requested range cannot be set Illegal subsystem capability specified Illegal device capability specified Illegal range index requested Illegal filter index requested Illegal gain index requested Illegal wrap mode requested Request not supported by subsystem The specified external clock divider is out of range Illegal gate type specified 261 Appendix B 262 Error Number 39 40 41 42 43 44 45 46 47 48 49 50 60 61 62 63 64 65 66 67 68 Description Illegal device handle specified Illegal subsystem handle specified The requested subsystem cannot be allocated The requested subsystem cannot be deallocated List could not be freed because buffers remained on the transfer list Another subsystem on the device is already running Channel list has been filled incorrectly Selected clock and trigger sources may not be used together Driver could not allocate needed memory Triggered scan is not available in single value mode External clock is not available in single value mode Illegal resolution index specified The A D subsystem has a trigger error The A D subsystem has an overrun error The D A subsystem has a trigger error The D A subsystem has an underrun error There are not any buffers on the ready queue Invalid CPU DT Open Layers requires an 80386 or above Invalid mode of Windows 3 1 DT Open Layers requires enhanced mode
101. dd an external trigger to the program Suppose the hammer mechanism outputs a steady TTL signal when it is ready to drop the hammer We will use this TTL signal as the trigger to start acquiring the burst of data Following the instructions in your hardware manual connect the signal from the hammer mechanism to the external trigger input on the screw terminal panel You also need to connect the ground Now click the Timing button in the A D Advanced Configuration dialog box Leave the clock source as Internal we are not changing the clock Select External under Trigger Source and leave the mode as Normal Click OK to close the Timing dialog box Now that you have defined the channel list and set up an external trigger click OK to close the dialog box Example on Disk The TRIGGER VEE example program in the Examples Dataacq directory shows how to set up a user selectable trigger This example does not use burst mode The Set Trigger object receives input from an Enum object which indicates whether the user wants to use an internal or external trigger The Set Trigger object overrides any trigger settings in the Timing dialog box 107 Chapter 4 108 What s Really Going On In this example the A D Config object executes first configuring the A D subsystem for burst mode and setting up the external trigger Only enough memory for the data queues is set aside for the amount of data specified in the burst mode secti
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103. e poy Pol F hEubess i To Fie myF ied AD Config H M ub y R Gea Fie t Prefun 2 Open ETRE Get Dats Panel To Fig J To Fit a E Clear Pile AL Pree amp Open i A WRITE TEST a EOL Figure 68 Using theTo File ObjectTo Write Data to a Text File The A D Config object configures the A D subsystem for two channels each sampled at 1 kHz Burst duration is enabled for 2048 samples Because the Get Data Panel objects are set to retrieve 512 samples you have to loop four times to read all the collected data samples 512 4 2048 samples Figure 69 shows the A D Advanced Configuration dialog box 126 Analog Input No need to enable WriteTo File when using the To File object Figure 69 Configuring To Write to File Using the To File Object When you run this program the A D subsystem acquires a burst of 2048 samples and stores them in the Mixed Data Buffer The two Get Data Panel objects each retrieve 512 samples from the individual channel s data queues every time the For Count object loops Two files are written MYFILEO and MYFILE1 In this example they are text files Figure 70 shows what MYFILEO looks like in Windows WordPad 127 Chapter 4 128 T myFilet WordPad ol Fie Edd Mew Ime Poma Hep F 07324 1513 2 4462690625 4 150390625 4 48 73046875 3 d091959125 1 0544875 1 577140432375 3 730496075 4 71191d0625 4 184535703125 234315 0 234375
104. e Choose a faster rate Consult your data acquisition hardware manual for minimum rate information Requested Rate exceeds the maximum throughput available with the current external clock frequency Check your external clock rate and adjust the information given to DT VPI Requested Rate is less than the minimum throughput available with the current external clock frequency Check your external clock rate and adjust the information given to DT VPI Combination of Delay and Pulse Width exceeds the maximum throughput of the Counter Timer device 1 Delay Pulse Width must be less than the maximum frequency of the clock source Combination of Delay and Pulse Width is slower than the minimum throughput of the Counter Timer device 1 Delay Pulse Width must be greater than the minimum frequency of the clock source Combination of Delay and Pulse Width exceeds the maximum throughput available with the current external clock frequency 1 Delay Pulse Width must be less than the maximum frequency of the clock source Combination of Delay and Pulse Width is slower than the minimum throughput available with the current external clock frequency 1 Delay Pulse Width must be greater than the minimum frequency of the clock source 257 Appendix B 258 2059 2060 2061 2062 2063 2064 2065 2066 2067 2068 2069 2070 2071 2072 2073 2074 2075 2076 2077 2078 Requested Measure Frequency Duration is out o
105. e If you need more space to the left of the Noise Generator object drag the work area to the right 6 Select Data gt Continuous C gt Real Knob and place the knob to the left of the Function Generator object 40 Your First Program Ampus Tire Span Zim _ Boise AF Kum Points H6 Connect the data output pin of the Real Knob object to the data input terminal of the Noise Generator object as shown in Figure 20 ies ee Apa che 1 Figure 20 Adding a Knob Step 3 Run Run the program 1 Click the Run button By default the noise amplitude is 0 Adjust the amount of noise by turning the knob with your mouse Run the program again With the noise amplitude set at 65 the output looks something like that shown in Figure 21 41 Chapter 3 42 TA Ampiude Tite Span Tim meine ii Hun Points 56 e Li Figure 21 Output when User Sets the Noise Level to 65 4 Save your program Data flow determines the order of execution The Noise Generator object is not executed until the Real Knob object executes The a b object is not executed until both the Function Generator and the Noise Generator objects have executed but it does not matter which one executes first Finally the Waveform Time object executes only after the a b object has executed Your First Program Lesson 3 Acquire Analog Data 8 minutes You can easily incorporate data
106. e Hardware dialog box see page 87 You are using Polled I O or PCI Bus Mastering if you leave Use DMA Data Transfer unchecked in the Hardware dialog box default Single Value is performed by the Get Single Value object For analog output the situation is similar You are using the DMA transfer method when you use the Put Data Panel or Put Data Function object and check Use DMA Data Transfer in the Hardware dialog box see page 153 You are using Polled I O if you leave Use DMA Data Transfer unchecked in the Hardware dialog box default Single Value is performed by the Put Single Value object To read the table first locate your board in the left column For each board at least one row exists with each row containing a pair of stars From each pair one star is in one of the Analog Input Subsystem columns and one star is in one of the Analog Output Subsystem columns Together the two stars indicate a valid combination of transfer modes when using the analog input and output subsystems simultaneously in a VEE program using DT VPI 195 Chapter 7 For example the row for the DT01 EZ board contains only one pair of stars Analog Input Single Value and Analog Output Single Value Therefore if you are using the DT01 EZ board you can use the analog input and output subsystems simultaneously only when using the analog input subsystem with the Get Single Value object and the analog output subsystem with the
107. e VEE window or the open view of a UserObject where you group objects together When you open a program it is loaded into the work area XEQ Pin A pin that forces the operation of the object even if the data or sequence input pins have not been activated See also Control Pin Data Input Pin and Sequence Input Pin Numerics 727 VEE example program 246 A A D Config object 26 44 51 81 about trigger acquisition 110 accessing unsecured UserObjects 240 Acq Status object 100 122 142 173 183 acquiring data 43 a single value from a single channel 101 continuous analog data 48 96 from a single channel 92 from multiple channels 94 in burst mode 104 post trigger 111 pre trigger 109 111 single analog value 50 single digital input value 189 ADBURST VEE example program 104 246 ADCOLUMN VEE example program 246 adding an amplitude input 40 adding configuration objects 72 adding noise to a waveform 38 adding objects 14 31 44 51 61 67 adding terminals 23 adding user input 74 ADSIMPLE VEE example program 25 246 Index ADSINGLE VEE example program 103 246 advanced functions CompensationVolts 242 dtv ConfigSubSys 229 dtv GetChannelType 230 dtv GetCriticalThreshold 231 dtv GetData 232 dtv GetEncoding 235 dtv GetFileSize 138 235 dtv GetMixedBufferSize 236 dtv GetPreTrigData 233 dtv GetResolution 187 237 dtv GetSingleValueEx 238 dtv GetTriggerThreshold 239 dtv PutData 234 dtv PutSingleValueEx 238 dtv SetCha
108. e channels click on the entry in the Current Channels box the information for that channel appears in the Edit Channels box The Calculate Actual Rates checkbox refers to the actual rates that the analog input subsystem can achieve When this box is checked the Current Channels box reflects the actual sampling rates To view the sampling rate that you originally entered select the channel in the Current Channels box the original rate for that channel is displayed in the Edit Channel box By default the A D Configuration dialog box shows channel 0 in the channel list You can add as many channels to the channel list as your board can accommodate and you can remove all but one channel Your channel list is always sorted by channel number starting with the lowest number It is unnecessary to define the channel numbers sequentially as in channel 0 then 1 then 2 and so on You should note however that when you run the program DT VPI acquires data on the channels in the order that they appear in the channel list Selecting a Sampling Rate According to sampling theory the Nyquist theorem a data acquisition system should sample an analog input signal at least twice as quickly as the input s highest frequency component For example to accurately sample a 20 kHz signal the sampling rate should be at least 40 kHz Doing so avoids an error condition called aliasing in which high frequency input components erroneously appear as lower fr
109. e function 138 dtv GetMixedBufferSize 236 dtv GetPreTrigData 233 dtv GetResolution 237 dtv GetResolution function 187 dtv GetSingleValueEx 238 dtv GetTriggerThreshold 239 dtv PutData 234 dtv PutSingleValueEx 238 dtv SetChannelType 230 dtv SetCriticalThreshold 231 dtv SetCriticalThreshold function 163 dtv SetMixedBufferSize 236 dtv SetResolution 190 192 237 dtv SetTriggerThreshold 239 DTVEE DLL 229 DTVEE VH 229 DTVFILE VEE example program 131 142 247 duplicating an object 16 duration 208 duty cycle 205 207 Dynamic Data Exchange 139 180 E EASYPK VEE example program 247 e mail support 278 Enum object 107 equipment 43 50 61 66 70 error handling 121 errors aliasing 84 DT VPI 252 DT Open Layers 260 handling 121 175 monitoring acquisition 124 trapping 122 176 when reading from a file 175 when writing to a file 122 event counting 216 example programs 245 727 VEE 246 ADBURST VEE 104 246 ADCOLUMN VEE 246 ADSIMPLE VEE 25 92 246 ADSINGLE VEE 103 246 ALLCHAN VEE 138 246 ATLABFIL VEE 246 CAL2801 VEE 246 CAL2812 VEE 246 CAL2821 VEE 246 CALCJC VEE 246 CNTEVENT VEE 246 COHERENCE VEE 246 CONTFFT VEE 247 CTRIGGER VEE 212 247 299 Index 300 DABURST VEE 166 247 DACONT VEE 153 159 247 DAFILE VEE 177 247 DASIMPLE VEE 156 247 DASINGLE VEE 164 247 DDE VEE 141 182 247 DIN VEE 189 192 247 DIO VEE 190 247 DOUT VEE 191 247 DTVFILE VEE 131 142 247 EASYPK VEE 247 FIL
110. e in an unconfigured state immediately after they are taken off the DT DataAcq menu before you click the Configure button on the object If your program is intended to run with a variety of data acquisition boards design your program to check for the user s system capabilities For example if your program needs an external trigger then check for the availability of an external trigger with the Get Trigger object DataAcq C gt Get Config gt Get Trigger If an external trigger is not available your program should alert the operator Provide a means of stopping the program from the panel view If you start a program in the RunTime environment with the r option no tool bar is available therefore no Stop button is available The operator can stop the program by pressing Ctrl but it is good practice to provide a button in the panel view to stop the program If your I O is not embedded in your program transport your VEE IO file to the VEE RunTime environment When you transport your program to the run only environment include your VEE IO file Put the file in the C PROGRAM FILES AGILENT VEE PRO RUNTIME 6 0 directory of each run only system that will run your program If VEE IO is not in that directory a default VEE IO file is created and your program may not run correctly Load any data acquisition device drivers used by your program Use the Windows Control Panel icon according to the user manual provided with your hardw
111. e program by clicking Stop data output continues until the data queues and Mixed Data Buffer empty or until a Stop Acq object is executed 161 Chapter 5 States of a D A Channel The data queues and Mixed Data Buffer are filled by the Put Data Panel objects and emptied as the samples are output by the board To check how much memory is being used by the samples use the Acq Status object The Acq Status object also provides the state of the channel The possible states are listed in Table 7 Table 7 States of a D A Channel Status from Acq Channel Status Status Object Ready Subsystem is initialized but not started There is no data in memory yet Executing a Stop Acq or Set Config object returns all channels in the subsystem to Ready Waiting The channel is waiting for data because 1 The channel has data to output but another channel does not have data to output The subsystem is waiting for all channels to have data before it can go to the Running state 2 If the data mode is Allow Gaps the channel is experiencing a gap and is waiting for data to be available The last value received is continuously output until new data is received Running The hardware is outputting data on the channel or waiting for an external trigger Done The channel Stopped for one of the following reasons 1 The data mode is Gap Free and no more data is available 2 Burst mode is finished 3 Hardware errors such
112. e server or wait The server responds by sending data or executing procedures Earlier in this chapter we looked at sending data to a DDE server In the example shown in Figure 94 we will read the data back in to a VEE program The Put Data Panel object sends the data for output to an analog device _ Ed TF om ODE 3 7207 Ew 3 075 ee 3 10746 Togig z EEL 0 7156 Tihi Ei 1 321269 13 A277 4 009908 3 242 LBB 1 547060 DA J arc i o Figure 94 A Program to Receive Data through DDE In the To From DDE object I O C gt To From DDE PC by default the Application is Excel and the Topic is Sheet1 an Excel document Double click the empty horizontal bar below Sheet and fill in the information for the transaction as shown in Figure 95 Analog Output 1O Transaction READ REQUEET MEM fri T11 00c TEXT F TOKEN FORMAT PACE CELIH Figure 95 DDE Transaction Settings To Read Previously Acquired Data from Excel Leave READ REQUEST as is Click STRING FORMAT and change it to TOKEN FORMAT Click SCALAR and change it to 1D ARRAY then click SIZE to change it to TO END When working with DDE and using VEE as the client you typically need to find out how the server application expects the item in the conversation to be phrased The Item is a string specifying the starting row and column and the ending row and column from which the data should be read A colon separates the starting
113. e steps e Open the object menu right mouse button over the object and select Add Terminal C gt Data Input The terminals are automatically named A B C but you can rename them e Just place the mouse pointer over the terminal input area and press CD 23 Chapter 2 Deleting Data Input or Output Terminals from an Object To delete data input or output terminals from an object perform these steps 1 Open the object menu and select Delete Terminal c gt Input 2 Choose the input to delete 3 Click OK Or you can just place the mouse pointer over the terminal and press C Renaming a Terminal To rename a terminal perform these steps 1 Double click the terminal The Name input field is highlighted 2 Type the new name and click OK 24 Understanding Propagation In conventional programming languages such as C BASIC or Pascal the order in which program statements are executed is determined by a set of sequence and selection rules Generally statements are executed in the order they appear in the program except where statements cause execution to branch to another statement or section of code In VEE the general flow of execution through a program is called propagation Propagation through a program is not determined by the geographic locations of the objects in the program but rather by the way the objects are connected Propagation is primarily determined by data flow whi
114. e the Multi channel File option by clicking the checkbox Leave the default file name MULTCHAN DTV The format is always VEE binary when using the Multi channel File option Enter an aggregate sampling rate such as 4000 Hz in the Aggregate Rate Hz edit box Then click the Add button three times to add three channels Figure 76 shows how the dialog box should look when you are done configuring Analog Input Advanced Caalequialen les Dine Anadag lait 0 ease AN T FERE cet GA R Cieed e Oare OGL PF tito Figure 76 Configuring the A D SubsystemTo Write Three Channels to a Single File Click OK to close the dialog box To run the program click the Run button For each of the three channels 1024 samples are acquired This data is retrieved by the Get Data Panel objects in two passes of 512 points each Most importantly this data is written to the file MULTCHAN DTV in raw binary format while the data is being acquired 137 Chapter 4 138 Example on Disk The MULTFILE VEE example program reads in a multiple channel file named MULTCHAN DTV It displays one channel from the file at a time offering a little dialog box for you to specify which channel you are interested in The ALLCHAN VEE example program illustrates how to create a multiple channel file without using the A D Advanced Configuration dialog box Instead the program uses the Get Multi Channel Mode and Set Multi Channel Mode objects as well as
115. ect that configures the input port one object that gathers the data and one object that displays the data 1 Select DT DataAcq C gt Digital In Config and place the Digital In Config object in the left of the work area This object configures a digital port for input 2 Select DT DataAcq gt Data gt Get Single Value and place this object to the right of the Digital In Config object The Get Single Value object acquires one sample from the digital input port immediately upon executing 3 Select Data gt Constant C gt Int 32 and place the Int 32 object to the left of the Get Single Value object To execute the Get Single Value object must have all inputs satisfied However when doing digital input or output the channel number is meaningless Therefore this object merely provides an input to the Get Single Value object 4 Select Flow C gt Repeat C gt Until Break and place the Until Break object above the Get Single Value object 5 Select Display gt Logging AlphaNumeric and place the Logging AlphaNumeric object to the right of the Get Single Value object 6 Connect the objects as shown in Figure 34 67 Chapter 3 5 a ee Logging Alphabiumeric Configune toutes il Figure 34 A Simple Program To Acquire Digital Input Step 3 Configure the Digital Input Port Before you can run the program you need to configure the digital input port on the data acquisition board using t
116. ed in your computer a dialog box similar to that shown in Figure 41 appears asking you to specify the board to use Select Device and Subsystem xX ptg C Analog Inpa Device Hama ema iri Heip Sub system to we Figure 41 Choosing One of Several Installed Devices Note This dialog box appears only if you have more than one data acquisition board installed in your system or more than one subsystem unit on that board Select the name of the board you want to use from the Device Name drop down list and then select AD Unit 0 from the Subsystem To Use drop down list and click OK 82 Analog Input Note The name of the board is the name assigned to it when its device driver was installed Select the board that has the capabilities you need for analog input Building a Channel List The A D Configuration dialog box shown in Figure 42 is used to build a channel list which specifies which channels you intend to use for analog input and the sampling rate and gain for each channel Figure 42 The A D Configuration Dialog Box 83 Chapter 4 84 Take a moment to consider the external connections you have made For each channel you intend to use enter the gain in the Gain edit box and the sampling rate needed in the Rate Hz edit box then click Add The channel number gain and associated rate are added to the channel list in the Current Channels box If you need to edit one of th
117. ed to the sequence in pin of a Stop Acq or Close Subsystem object if present See the Analog Input example Trapping Errors starting on page 122 for more information Analog Output Reading Data From a Disk File As you learned in the section Sending Data to a Disk File starting on page 125 you can send acquired data to disk in one of two ways One way is to use the VEE To File object This data can be read in with a From File object I O C gt From O gt File The data can then be used with a Put Data Panel or Put Data Function object If you need to read and output data very quickly over 50 kHz DT VPI provides the capability to read the data directly from a disk file and pass it immediately to the DAC The file is treated as though it were a data queue The binary file contains a special file header which includes all the information necessary to convert the raw data when it is output The file header is described in Appendix C of this document The DAFILE VEE example program in the Examples Dataacq directory shown in Figure 93 creates a file of data on disk Then the D A subsystem reads the data and directly outputs it to the D A subsystem 177 Chapter 5 Figure 93 Example on Disk DAFILE VEE Although the example program DAFILE VEE configures the D A subsystem programmatically you need to know how to use the D A Advanced Configuration dialog box Set up the channel list just as you woul
118. ed until all of its data input pins have received data e An object finishes executing only after all appropriate data output pins have been activated In VEE you can change the order of execution by using sequence input and output pins If possible let data flow control the execution of your program In general the rules of data flow through a program are as follows e Start objects operate first The Start object is used to operate an individual thread e Objects with no input pins operate next Objects with data input pins operate when all connected input pins are satisfied Recall that connecting sequence input pins is optional 27 Chapter 2 28 Your First Program Lesson 1 Create A Simple Program 0000200 31 Lesson 2 Modify Your Simple Program 5 38 Lesson 3 Acquire Analog Data 0 6 0c e cece eee 43 Lesson 4 Acquire with Get Single Value 50 Lesson 5 Output Analog Data 0 6 cee eee ee 60 Lesson 6 Digital Input and Output 000 66 Lesson 7 Change the Configuration Programmatically 70 What s Next 0 ccc deed Ped ede eee ee dee tir pidt ewes 78 29 Chapter 3 30 Now that you have learned to work with objects and the VEE user interface we will look at how to use objects to create VEE programs This chapter contains seven lessons each with several steps By completing these tutorial lessons you w
119. edly output until more data element is present Allow Gaps is found in the D A Advanced Configuration dialog box See the DT VPI online help for more information e When using a relatively slow output rate use the Acq Status object to check on how many data points are waiting to be written to the channel s data queue If the Put Data Panel or Put Data Function object attempts to write data to a full data queue and the D A subsystem is configured for Gap Free data mode error 2012 is raised e When configuring leave Calculate Actual Rates unchecked until you are done creating the channel list Doing so avoids having DT VPI take the time to calculate between each channel entry e Use the Close Subsystem object after your data has been output to release system resources such as memory DMA channels and interrupts e Use the Put Data Function object instead of the Put Data Panel object The Put Data Function object runs more efficiently because it is a function call not a UserObject 183 Chapter 5 184 D Digital Input and Output Connecting External Devices 0 00 0c eee eee 187 Configuring for Digital I O 0c eee eee 187 Acquiring a Single Digital Value 004 189 Outputting a Single Digital Value 06 191 185 Chapter 6 186 To communicate with a device that is itself digital many data acquisition boards provide digital input DIN
120. el 156 Outputting Analog Data Continuously 159 Outputting a Single Analog Value 0 0006 164 Outputting a Burst of Data 0 e ee eee eee 166 Changing the Subsystem Configuration 5 170 Handling Acquisition Errors 000 c cece 175 Reading Data From a Disk File 000005 177 Receiving Data From DDE 00 c eee eee 180 Optimizing Analog Output 00 c cece 183 145 Chapter 5 146 A process complementary to analog to digital conversion called digital to analog conversion D A conversion changes digital data into analog voltages This process permits the computer to drive chart recorders audio amplifiers process actuators and other devices requiring analog input Many data acquisition boards have both A D and D A converters Typically data acquisition boards have one or two D A converters DACs Each DAC is a channel This chapter discusses how to control your data acquisition hardware to perform analog output operations It includes information on configuring the DACs and setting the sampling rate Special attention is paid to setting the sampling rate to output data generated by the Function Generator object This chapter also includes many example programs and explanations of using the data acquisition objects provided by D TVPI You will learn how to create programs to e Output analog data e Out
121. el View Panel View The view of a program in VEE that shows only those objects needed for the user to run the program and view the resultant data You can create a panel view to meet the needs of your users Pin An external connection point on an object to which you can attach a line Glossary Point See Sample Pointer The graphical image that maps to the movement of the mouse A pointer allows you to make selections and provides you feedback on a particular process underway VEE has pointers of different shapes that correspond to process modes such as an arrow crosshairs and hourglass Pop Up Menu A menu that is raised by clicking the right mouse button For example you can raise the Edit menu by clicking the right mouse button in an empty area in the work area Or you can raise the object menu by clicking the right mouse button on an inactive area of an object PostRun The set of actions that are performed when the program is stopped PreRun The set of actions that resets the program and checks for errors before the program starts to run Priority Thread A priority thread executes to completion blocking all other parallel threads from executing Certain of the I O objects for devices and interfaces will host a priority thread Program In VEE a graphical program that consists of a set of objects connected with lines The program typically represents a solution to an engineering problem Promote To convert fro
122. ember this rate is the sampling frequency of the data points then the points are spread farther apart so the duration of the output waveform increases To achieve a duration long enough to sustain continuous output from the DAC as opposed to enabling Burst mode then you should either reduce the D A Rate to 2000 Hz 1000 points divided by 2000 samples per second yields a duration of 1 2 second or increase the NumPoints setting in the Function Generator object to 10000 points 10000 points divided by 20000 samples per second also yields 1 2 second Analog Output Example on Disk The DACONT VEE example program in the Examples Dataacq directory has a Function Generator object with settings of Frequency of 10 Hz over a TimeSpan of 1 s and 1000 points These settings generate a cosine wave with 10 cycles per second and 100 points per cycle The D A Rate is set for 1000 Hz The frequency of the output waveform is 10 Hz 1000 divided by 100 over a duration of 1 s 1000 Hz 1000 point Selecting an Output Range and Type To select the output range click the Hardware button from the D A Configuration dialog box The Hardware dialog box shown in Figure 81 gives you the opportunity to select an output signal range from those available on your board Use this range in conjunction with the gain setting in the D A Configuration dialog box to most closely match the actual range of your output signal Hardware x Chanal
123. empt this lesson in stages First we will make sure the Simple analog input is working Then we will add the configuration objects but set them so they do nothing Then we will add the objects to change the configuration 1 Select the Until Break object and delete it by clicking the Cut button on the tool bar The connections to and from the object are deleted as well The A D Config Get Data Panel and Waveform Time objects remain Minimize the Get Data Panel object by clicking the button in the right hand corner of the object Click the Configure button on the A D Config object The A D Configuration dialog box appears The default configuration in the dialog box specifies that channel 0 is sampled at a rate of 1000 Hz samples per second and at a gain of 1 These settings are sufficient for our example Click OK to close the dialog box and to configure the A D subsystem with these settings Minimize the A D Config object Set the external function generator to output a waveform sine will be fine at a frequency of 100 Hz Make sure it is connected to A D Channel 0 and turned on 71 Chapter 3 72 7 Run the program After clicking the Auto Scale button on the Waveform Time object the output looks something like that shown in Figure 36 Figure 36 Another Simple Analog Input Program Step 3 Add the Configuration Objects The Set Sampling object is a configuration object that enables you to
124. equencies after sampling see Figure 43 Often the erroneous signal is indistinguishable from a correctly sampled signal Some data acquisition boards have anti aliasing filters built right into them Analog Input Alias frequency a fd Sampling pulses Figure 43 An Aliased Frequency as a Result of Sampling Pulses Too Far Apart Filtering an Analog Input Signal If your board has anti aliasing filters click Advanced The dialog box shown in Figure 44 appears you can use this dialog box to specify more details about the analog input configuration In the Filter Hz edit box select from the available hardware low pass filter cutoff frequencies Anaing Input Advanced Coniqerahen Tast Dur Charl Gan Fiaa Hd Fim HE Dade biod OK e fr g Esp Fe J TF Buni Darshini PF Epi r D bei chara Fia ee i ve hal T F ssp Pe cene Cag ec i Cuen Charest Crema Gan Resia Piah ode 9 Bunt Fomst Fis m Li 1i 10S Hos gap ines Hors thra Harby _ 7 Codeine Actual Faster P Disi Auto COL F Autre Sted Figure 44 The A D Advanced Configuration Dialog Box 85 Chapter 4 Selecting the Gain Some data acquisition boards provide several input ranges by using software programmable gain amplifiers or gain When you considered which data acquisition board to use with your VEE programs one of the considerations was the range of the analog input signals you would be working w
125. ernal sensor or measuring device See the hardware manual for your board for information on connecting external devices Configuring for Analog Input Now that you have connected the external devices that provide your VEE program with analog input it is time to start building your data acquisition program Every VEE program that includes data acquisition needs a subsystem configuration object The first five menu items in the DT DataAcq menu access subsystem configuration objects For an analog input program you need the A D Config object Select DT DataAcq gt A D Config and click the Configure button Table 2 directs you to the appropriate dialog box to perform various configurations These configurations are discussed in the following pages Table 2 Configuring the A D Subsystem To Configure In the A D Config Object click The A D channel list Configure Sampling rates and gains for channels Configure Sampling rates gains filters burst mode write Configure then Advanced to file and data mode Gap Free or Allow Gaps for channels The input voltage range Configure then Hardware The input channel type Configure then Hardware The clock source Configure then Timing The trigger source and triggering mode Configure then Timing 81 Chapter 4 Selecting a Board when More than One Data Acquisition Board Is Installed If you have more than one data acquisition board install
126. es the channel number the appropriate gain is automatically used to acquire the signal Acquiring a single value can be performed only when the channel is in the Ready state 102 Analog Input Example on Disk The ADSINGLE VEE example program in the Examples Dataacq directory shows how the Get Single Value object is used with a For Count object labelled Select of Samples in this example to acquire a certain number of samples The data is passed to a Collector object is converted into a waveform in a Build Waveform object and finally displayed The Timer object times how long it takes from the start of acquisition to finish 103 Chapter 4 Acquiring a Burst of Data If you know exactly how many samples of data you want to acquire or the time period over which you want to acquire use burst mode For example suppose you want to measure several aspects of a hammer blow on an object The hammer blows occur once every second You wish to measure the effect with accelerometers connected to channels 0 1 and 2 You have obtained the proper accelerometers and made the proper input connections Figure 57 shows the program Figure 57 A ProgramTo Acquire Data in Burst Mode Example on Disk The example program ADBURST VEE in the Examples Dataacq directory is a similar program using only one channel configured for 512 samples in burst mode 104 Analog Input Configuring for Bur
127. et Channel Buffer Size object 117 170 Get Channel Filter object 118 171 Get Clocking object 117 170 Get Config objects 117 170 Get Data Function object 142 199 Get Data Mode object 118 171 Get Data Panel object 26 44 94 143 matching to channel list 92 Get Multi Channel Mode object 118 138 171 Get Range object 117 170 Get Sample Clock Frequency object 171 Get Sampling Clock Frequency object 118 Get Sampling object 72 117 119 170 173 199 Get Single Value object 51 53 55 67 101 189 Get Trigger object 117 170 214 225 getting a single value 50 glossary 279 graphs 93 H handling errors 175 HCHAN1 VEE example program 247 HCHAN2 VEE example program 247 help starting DT VPI on line help 11 starting VEE on line help 11 l icon view 18 Import Library object 229 installing data acquisition boards 3 device drivers 4 DT VPI 5 summary 2 VEE 4 Integer Constant object 165 Integer object 51 67 L lessons acquiring a single analog value 50 acquring analog data 43 changing the configuration programmatically 70 creating a simple program 31 digital input and output 66 modifying a simple program 38 outputting analog data 60 Line Probe button 26 loading device drivers 225 Logging AlphaNumeric object 67 93 128 301 Index 302 M MAGBIN VEE example program 247 measure frequency 205 MEASURE VEE example program 248 measuring frequency 218 measuring temperatures 241 me
128. et Help Should you run into problems installing or using DT VPI our Technical Support Department is available to provide prompt technical assistance You will find their number in Appendix D If you are outside the U S or Canada call your local distributor whose number is listed in your Data Translation product handbook XX Installing DT VPI Step 1 Install Your Data Acquisition Board 3 Step 2 Install the Device Driver 0 0 0000 rrr 4 Step 3 Install VEE 0 cece eee ee 4 Step 4 Install DIV PL iocnsosiwidaddicisiote viene de tees 5 Chapter 1 This chapter tells how to install DT VPI The installation is primarily automatic and requires only a few minutes if your computer is already set up and running There are four steps to get up and running These four steps are described below and illustrated in Figure 1 1 Install your data acquisition hardware using the hardware user manual or getting started manual that comes with your board 2 Install the device driver for your hardware using the device driver documentation or getting started manual that comes with your board 3 Install VEE Pro or VEE OneLab version 6 0 or a later version using the documentation that is provided with VEE 4 Install DT VPI by following the steps outlined in the next section V Install driver V Figure 1 Installation Steps for VEE with DT VPI Installing DT VPI Step 1 Instal
129. f range The frequency duration must be between 1 ms and 4 294 967 296 ms Invalid Counter Timer mode for this operation Parameters set with a Set Config object are not available for this counter timer mode nable to convert Coord to Int32 nable to convert Complex to Int32 nable to convert PComplex to Int32 nable to convert Spectrum to Int32 nable to convert Enum to Int32 nable to convert Text to Int32 nable to convert Coord to Real nable to convert Complex to Real nable to convert PComplex to Real nable to convert Spectrum to Real nable to convert Enum to Real nable to convert Text to Real nable to convert Coord to Text nable to convert Complex to Text nable to convert PComplex to Text Ge O a Ee SE se SG a GS Sc oe Ss G nable to convert Spectrum to Text Requested Scan Mode not supported by this device Device driver version lt version number gt is invalid The device driver must be version 2 1 or greater 2079 2080 2081 OLDAAPLDLL version lt version number gt is invalid OLDAAPI DLL must be version 2 11 or greater Reinstall DT VPI to install the correct version OLMEM DLL version lt version number gt is invalid OLMEM DLL must be version 2 12 or greater Reinstall DT VPI to install the correct version Driver underrun error DT VPI could not process Windows messages This is typically caused when a single object execution is too slow 259 Appendix B 260 DT O
130. f you did not configure it as such Similarly the Get Trigger and Set Trigger objects ensure that the trigger is external When the delay period 0 5 ms is over a pulse of 0 5 ms is output from the board and reaches the A D external trigger input The A D subsystem which has been waiting for the external trigger then begins acquiring data Figure 109 shows the timing diagram for this example QT output ee a ADE Ext Trigger AID Clock JL JL I LIL Figure 109 Timing Diagram for a Counter Timer used as aTriggerTo Start Acquisition 214 Using Counters and Timers Taking it Further An External Trigger to the C T Using the counter timer subsystem as an external trigger to the A D or D A subsystem gives you flexibility in determining when the A D or D A starts Although the value for Delay in the C T Configuration dialog box cannot be set for much more than 0 5 s you can control programmatically when the Start Acq object is executed and therefore control when the trigger occurs Furthermore if you want to externally trigger the A D or D A subsystem but need to use a different type of signal than the one allowed in the A D Configuration dialog box under Timing then supply an external trigger to the C T subsystem itself To do this set the C T Gate to an External source and then choose from among the choices of Gate Types Figure 110 shows the timing diagram for this example Gate ee ee GT output ft AYO Exell Trigger
131. g To clear the dialog box click OK Any data in memory at the time is flushed out You need only click Run Start to restart your program For example if a Get Data Panel or Get Data Function object tries to retrieve data for a channel and not enough samples are available an error is raised see Figure 66 Similarly if the Put Data Panel or Put Data Function object is executed before it has at least 0 5 seconds of data an error is raised In both cases the subsystem is no longer running so a Stop Acq object is not needed If a Get Data Panel or Get Data Function object tries to retrieve data for a channel that has stopped an error is raised see Figure 66 Similarly if the Put Data Panel or Put Data Function object is executed when it has less than 0 5 seconds of data an error is raised In both cases the subsystem is no longer running so a Stop Acq object is not needed Any data in memory at the time is flushed out You need only click Run or Start to restart your program The Acquisition Ouiput is compte for ihe channe This is typically caused Ey processing Thal can nel keep up vith The aqquisiben or output rate in Comaiied Funchon atlas Object Tite GetiataPnmitres Ctyact Typa Cail Error number 2012 C Figure 66 Error Is Raised when Not Enough Data Is Available in Memory 121 Chapter 4 122 Errors When Writing to File When writing data directly to a file you want to be sure of the data s
132. he Digital Input Config object If you were performing digital output you would use the Digital Output Config object You use one configuration object for each digital port 1 Click the Configure button on the Digital In Config object The Select Device and Subsystem dialog box appears 2 If you have more than one data acquisition device installed choose the device you want to use If that board has more than one digital input port you can select from the choices You should select or see a grayed option for DIN Unit 0 in the Subsystem to Use list box 3 Click OK to close the dialog box and to configure the digital port for input Your program is ready to run Make one last check to be sure your equipment is correctly connected and turned on 68 Your First Program Step 4 Run Run your program 1 The output is displayed in the Logging AlphaNumeric object as shown in Figure 35 In this example only bit 0 is being sampled E e ek ads Bei ded he base Figure 35 Output from the Digital Input Program 2 Stop the program by clicking the Stop button E on the tool bar Step 5 Save Your Program Save your program 1 Click the Save button Mal 2 Inthe Save File dialog box that appears type a name such as DLVEE 3 Click Save to close the dialog box Chapter 3 Lesson 7 Change the Configuration Programmatically In Lesson 7 you will modify the simple analog input program you create
133. he Frequency of the Board s Internal Clock 218 Using Counters and Timers Configuring the C T to Measure Frequency Select the C T Config object and click Configure Set the mode to Measure Frequency See your hardware user manual for more information on the definition of an event Under Clock Source select Internal or External depending on whether you want to measure the frequency of the internal clock or an external signal For this example the clock source is the internal oscillator though measuring your internal oscillator is not very useful For this example the pulse type can be either High to Low or Low to High If you set the Gate Source to External then frequency of occurrence is measured only when the specified gate High Level Low Level Rising Edge Falling Edge is active Under Duration secs indicate the period over which you want to count events In terms of accuracy the more periodic events you count the more accurate the result If you count ten periodic events the accuracy is within 10 If you count 100 period events the accuracy is within 1 e equency duration 1 1 mjas Javarton 100 PercentAccuracy 219 Chapter 8 What s Really Going On When you run this program the counter timer begins counting events on the internal or externally supplied clock In this example we are measuring the frequency of the internal oscillator When the Get Data Panel object is executed the
134. he user selects a value to output using the slider and the meter displays the acquired digital value Digital Input and Output Outputting a Single Digital Value Outputting a single digital value is similar to acquiring a single value except that you use a Put Single Value object instead of a Get Single Value object You use one Put Single Value object for each digital port The Digital Out Config object DT DataAcq gt Digital Out Config configures the hardware for digital output and defines a subsystem handle We have retitled the Int 32 object as Channel and the Formula object as DoutMux The DOUT VEE example program in the Examples Dataacq directory shown in Figure 98 continuously outputs user selected digital values to a digital device l Bad Bai Baz 8 EZ Eos Figure 98 Example on Disk DOUT VEE ca a 191 Chapter 6 192 After configuring the hardware for digital output select the output value by clicking the toggle buttons One button exists for each digital line Depressing the button sets the corresponding bit to a logical 1 Leaving the button up sets the corresponding bit to logical 0 When you run this program the values of each bit are added together in the UserObject DoutMux resulting is a decimal value This value is passed to the Put Single Value object and output to the digital device Example on Disk The DIN VEE example program in the Examples Dataac
135. hield Wizard dialog box appears 5 Click Next The license agreement dialog box appears 6 Click Yes 7 Select whether you want to use DT VPI with VEE Pro or with VEE OneLab then click Next The files are copied to your hard drive 8 Click Finish Chapter 1 Quick Start The Basics 023i 220de0rsdicsdiaed eueadebiadeaweseiateeeues 8 Working with Objects 0606 6 cece eens 14 Understanding Pins and Terminals 004 22 25 Understanding Propagation 60 e cece e eee ee Chapter 2 The Basics In this section you will learn how to start and quit VEE You also will learn how to access the on line help Starting VEE To start VEE follow these steps 1 Click Start on the task bar 2 Click Programs 3 Click VEE Pro 6 0 or VEE OneLab 6 0 When VEE is running a button with the VEE logo appears on the task bar The VEE Pro window shown in Figure 2 or the VEE OneLab window shown in xx appears You can tell that DT VPI is installed because VEE s main menu has DT DataAcq present title bar menu bar tool bar File Edit View Debug Flow Device 1 0 Data D1 Datadcg Display Window Help OSES ruses VERA Mo Sms Untitled L Main Figure 2 The VEE Pro Window with DT VPI Installed Chapter 2 title bar menu bar tool bar Fe YEE OneLab File Edit View Debug Flow Device Oss ru sae elo Data DT Datadcg Display Window Help AO Gm Ay
136. iftaet O a Get senping f Set Sampling b Put Data Panel Phase Deg o i Time Span 10 Mi Peinki j Raal Array w New Fiata I Figure 90 A Program To Change the Output Rate Programmatically When you run this program 10 000 points 10 seconds from the 20 Hz cosine signal generated by the Function Generator object are passed to the first Put Data Panel object Since Automatic Start is selected the Put Data Panel object passes the data to the D A Analog Output subsystem which immediately starts outputting the data The Put Data Panel object finishes executing even though all the data has not yet been output from the board The Delay object shown in Figure 91 allows the hardware some time to output the data before the subsystem is stopped by Stop Acq Alternatively the Acq Status object can be used to verify when all the data has been output Figure 91 The Same Program Using Acq Status instead of Delay The Get Sampling and Set Sampling objects used as a pair allow a change to the D A sampling rate Because the Set Sampling object expects the Rate input as a real array containing one value for each channel the new rate is in an Allocate Array object We have retitled this object as Real Array w New Rate This object allocates a one dimensional array containing only one value we are using only one channel which is the new sampling rate in hertz We have also retitled the Int 32 object as Ch
137. ignal 2 A single value in such a representation Sampling Frequency See Sampling Rate Sampling Rate The frequency at which an analog signal is sampled usually in Hertz Hz For example if an analog signal is sampled 1000 times every second the sampling rate is 1000Hz or 1 kHz Glossary Save To write a file to a storage device such as a hard disk for safekeeping Scalar A data shape that contains a single value See also Data Shape Schema The structure or framework used to define a data record This includes each field s name type shape and dimension sizes and mapping Screen Dump A graphical printout of a window or part of a window Scroll The act of using a scroll bar either to move through a list of data files or other choices in a dialog box or to pan the work area Scroll Arrow An arrow that when clicked on moves you through a list of data files or other choices in a dialog box or moves the work area Scroll Slider A rectangular bar that when dragged moves you through a list of data files or other choices in a dialog box or moves the work area Select To choose an object an action to be performed or a menu item Usually you select by clicking with your mouse Select Code A number used to identify the logical address of a hardware interface For example the factory default select code for most HP IB interfaces is 7 Selection 1 A menu selection feature 2 An object or
138. igures the D A subsystem on the data acquisition hardware However the Put Single Value object does not refer to the channel list defined in the D A Configuration dialog box You need only specify the channel number as an input to the Put Single Value object usually in the from of an Int 32 Constant object 164 Analog Output The subsystem handle is passed to a Put Single Value object In addition to the subsystem handle the Put Single Value object needs to know which channel to use for output An Int 32 Constant object which we have retitled as Channel provides this information When you run the program as soon as it receives the data the Put Single Value object outputs one value to the specified channel 165 Chapter 5 Outputting a Burst of Data If you know exactly how many samples of data you want to output or the time period over which you want to output use burst mode The DABURST VEE example program in the Examples Dataacq directory shown in Figure 88 shows a simple program Wein iTe ing COW big bees i a Put Osta Panel Trace p Figure 88 Example on Disk DABURST VEE Configuring for Burst Mode You probably noticed that the program to output data in burst mode uses the same objects we have already worked with The difference lies in the configuration To set up burst mode you need to use the D A Advanced Configuration dialog box On the D A Config object
139. ill learn how to e Create save and run a simple program e Acquire analog data e Determine whether your hardware supports gap free continuous data transfer e Output analog data e Acquire digital input data and e Change a subsystem s configuration using objects in the program Your First Program Lesson 1 Create A Simple Program In Lesson 1 you will create a simple VEE program that displays a O generated waveform You will also print the VEE screen and save your program to a file 6 minutes Restart VEE if you previously quit it If VEE is already running clear the work area by selecting File O gt New Step 1 Add the Objects Fundamentally a VEE program consists of VEE objects connected to form an executable block diagram We will create a very simple program that displays a waveform 1 Select Device C gt Virtual Source C gt Function Generator Place the Function Generator object on the left part of the work area Select Display gt Waveform Time Place the Waveform Time object on the right of the work area as shown in Figure 11 31 Chapter 3 iver Tivep Fureion Crans Meg Frequency 100 Ande Dcos o fmm EON Phase trey Altec Tine Span 2am n Pepi alte Auto Scala Time Figure 11 The Objects in a Simple Program Note The tic marks and axes in the Waveform Time object have been removed in Figure 11 and in the remaining figure
140. ime In the edit box next to Item type r b 1 cl where b is the input value for the row number Because the For Count object starts with 0 and Excel s rows start at 1 we need to add 1 to the row number input In the edit box next to TEXT type a b where a is the array containing the data you want to write and b as you know is the row number Lastly you need to add two input terminals to the To From DDE object 141 Chapter 4 142 Optimizing Analog Input You can optimize analog input with DT VPI by doing the following Use burst mode whenever appropriate When acquiring data continuously use the Allow Gaps data mode when it is unnecessary to process every point Allow Gaps is found in the A D Advanced Configuration dialog box See the DT VPI online help for more information When using a relatively slow sampling rate use the Acq Status object to check on how many samples are available before reading them with the Get Data Panel object or Get Data Function object The Get Data Panel and Get Data Function objects do not return until all of the data points specified have been retrieved from memory When configuring leave Calculate Actual Rates unchecked until you are done creating the channel list Doing so avoids having DT VPI take the time to calculate between each channel entry Use the Close Subsystem object after your data has been acquired to release memory Use the Get Data Function
141. ing acquired data an object that configures the hardware and an object that outputs the data Optionally you might want to add an object that displays the data 1 Select DT DataAcq gt D A Config and place the object in the upper middle of the work area Select DT DataAcq gt Data C gt Put Data Panel and place this object under the D A Config object Select Display gt Waveform Time and place it under or to the right of the Put Data Panel object Select Device O gt Virtual Source C gt Function Generator and place the object to the left of the work area 61 Chapter 3 5 Modify the Function Generator object s Time Span to be 10 m milliseconds and its NumPoints to be 1000 6 Connect the objects as shown in Figure 31 Cange Furcion Ganerste Te El Put Data Panal 3 Furcion l Carins houor Faar N io Oan es tubiera d Darai Func d Dots Tread Phase cag a Tine Opa j r Pune Panta nie j Figure 31 Ready To Output Generated Data Step 3 Configure the D A Subsystem Before you can run the program you need to configure the D A subsystem on the data acquisition board 1 Click the Configure button on the D A Config object The D A Configuration dialog box appears as shown in Figure 32 62 Your First Program Figure 32 Configuring the D A Subsystem Note If you have more than one data acquisition board installed a dialog box ask
142. ing to be the new sampling rate for analog data acquisition The previous sampling rate was set in the A D Con figuration dialog box To avoid aliasing you must sample a sig nal at least twice as fast as the highest frequency component in the signal Since our signal is a 100 Hz sine wave then sampling at 200 Hz is the minimum sampling frequency we can use to avoid aliasing errors For more information on aliasing see Selecting a Sampling Rate starting on page 84 Set the Real Slider to 1000 Enter 1000 in the top most edit box This setting mimics the sampling rate you configured in the A D Configuration dialog box Select Data gt Allocate Array gt Real 64 and place the Alloc Real object to the right of the Real Slider object Click the text Lin Ramp to open a drop down list and select Init Value from the list Change the Size to 1 With your cursor over the object click the right mouse button to invoke the object menu and select Add Terminal gt Data Input From the small dialog box that appears select Init Value and click OK A new data input pin is added to the Alloc Real object Connect the Real Slider object to the Alloc Real object Connect the Alloc Real object to the available data input on the Set Sampling object The program looks like that shown in Figure 39 75 Chapter 3 76 Figure 39 All Objects Are in Place Your program is ready to run Make one last check to be s
143. ints in its Points edit box When you run this program 512 samples are acquired These values are stored in memory and when the program executes Get Data Panel tries to retrieve 10 000 values Obviously there is not enough data stored so an error is raised The subsystem stops running The Error output pin fires activating the Close Subsystem object Analog Input fioa Figure 67 A ProgramToTrap an Error The Close Subsystem object requires the subsystem handle as input In the example the Close Subsystem object gets the subsystem handle from the A D Config object Recall that the Get Data Panel object also outputs the subsystem handle However in this example the subsystem handle from Get Data Panel is not sent to the Close Subsystem object because if an error is raised in the Get Data Panel object all of its output data is invalid Note If an error is raised with a data acquisition object the hSubsys output on that object does not have valid data and therefore does not contain a valid subsystem handle 123 Chapter 4 124 The Stop Acq and Close Subsystem objects are control objects The Stop Acq object is used to halt data acquisition on the hardware and flush any unread data from the memory buffer The Close Subsystem object terminates a subsystem s configuration and deletes the subsystem handle A currently running subsystem stops Both objects require the subsystem handle as do the other d
144. irst by clicking the Stop button Ll on the tool bar If you have not saved your most recent changes to a file a dialog box asks you if you want to save your changes Select No to discard your changes Yes to save them to a file or Cancel to continue working in VEE 13 Chapter 2 14 Working with Objects In this section you will learn the basics of manipulating objects Clear your work area by selecting File C gt New Adding an Object to the Work Area In VEE each object is located in one of the menus To add a new object to the work area select a menu select one of the menu items and then click on the work area to place the object Try it now 1 Select the Device menu A drop down menu appears Move the mouse pointer down to the Virtual Source item A submenu appears From the submenu select Function Generator The menu closes and an outline of the object appears Move the mouse cursor anywhere in the work area and click once to place the Function Generator object shown in Figure 5 in the work area Function AHi J Fusan Cosine Fme 700 nome i Ochi o Fare d a Tresean iim Hum Pais a Figure 5 The Function Generator Object You can move cut paste clone iconize change the title of and resize objects with just a few clicks of the mouse These techniques apply to all objects in VEE not just those in DT VPI Moving an Object To move the Function Generator object 1 C
145. isition objects provided by DT VPI to write programs to acquire and output analog and digital data With the exception of Chapter 7 this manual does not mention particular boards Some boards support features that other data acquisition boards do not For example some have 16 bit resolution and some have 12 bit resolution Some have hardware anti aliasing filters such as DT3831 and some do not If you need assistance in determining what your board supports refer to the manuals that describe your board and device driver Determine what capabilities your board supports by checking the supported options table in your board s device driver documentation For example to determine if your board supports continuous data acquisition with gap free data check the row labelled Continuous Operation Support If there is Yes in the column under the A D subsystem then your board can continuously acquire gap free data Depending on the capabilities of your particular board some features may be grayed in the configuration dialog boxes A grayed feature indicates that the feature is unavailable for the selected data acquisition board xiv About this Manual Intended Audience This manual is written for engineers and scientists who have some experience with programming and working with instruments It assumes some knowledge of Microsoft Windows It is assumed you have VEE Pro 6 0 or VEE OneLab 6 0 from Agilent Technologies plus
146. it is not supported by the subsystem Fatal internal DLL error Please note what you were doing and call Data Translation This error is fatal you should exit and restart Windows Invalid subsystem type passed to a config object This error is raised if an invalid subsystem type is passed to an advanced configuration object Trigger Error Acquisition Stopped The subsystem received an external trigger while running Underrun error D A Operation clocked too fast A hardware error the hardware cannot keep up with the clock rate Slow down the output rate Overrun error A D Operation clocked too fast A hardware error the hardware cannot keep up with the clock rate Slow down the acquisition rate Event error A hardware error the counter timer subsystem in Count Events mode cannot keep up with the incoming events Slow down the event rate 2010 2012 2013 2014 2015 Operation cannot be performed while the system is running Use the Acq Status object to check the status of the subsystem to avoid this error The Acquisition or Output is complete for the channel This is typically caused when processing cannot keep up with the acquisition or output rate The A D or D A subsystem has stopped This error is raised when you try to read or write samples to a device that has stopped For the A D subsystem the subsystem stops when all of the memory set aside for incoming data is used To prevent this error you can
147. ital data acquisition is accomplished one value at a time using a Get Single Value object for each digital port First you need a Digital In Config object DT DataAcq C gt Digital In Config This object configures the hardware for digital input and defines a subsystem handle We have retitled the Int 32 object as Channel the User object as DinDemux and the Alphenumeric objects as Bit Number objects one through eight The DIN VEE example program in the Examples Dataacq directory shown in Figure 97 continuously acquires digital data from a digital device It can be used to verify the state of each bit in the digital input value 3 Lintil Break i DiN Cong p F i i i Get Singe Value DiriDa mts __ Chair W hy 7 Figure 97 Example on Disk DIN VEE When you run this program a value on each connected digital line is immediately acquired This value is masked in the UserObject DinDemux revealing the state 0 or 1 LOW or HIGH of each bit in the value 189 Chapter 6 190 Note If you want to change the bit resolution of the DIN subsystem and your board supports this option you can use the advanced function dtv SetResolution See Chapter 10 Advanced Functionality for information on this function Example on Disk The DIO VEE example program in the Examples Dataacq directory demonstrates continuous acquisition and output of digital data T
148. ith You should have chosen a board that most fully covers the analog input range you are interested in measuring Doing so gives you the greatest number of samples in that range and thus the greatest accuracy Depending on the capabilities of your data acquisition hardware you can select a gain of 1 2 4 or 8 or 1 10 100 or 500 Use the following equation to determine which gain to use HardwareRangeSetting Gain RangeOfInputSignal The ranges for HardwareRangeSetting are board specific Consult your hardware user manual or check the Hardware dialog box click Hardware to see the ranges available for your board s current configuration For example suppose you selected a range of 10 V from the available choices in the Hardware dialog box If you select a gain of 8 the range of the input signal can be as small as 1 25 V since 10 divided by 8 equals 1 25 while still maintaining full sampling accuracy If you want a gain other than 1 select a gain from the drop down list box To add the new gain value to the channel list click Add 86 Analog Input Selecting an Input Range and Type To select the input range click the Hardware button from the A D Configuration dialog box The Hardware dialog box shown in Figure 45 gives you the opportunity to select an input signal range from those available on your board Use this range with the gain setting in the A D Configuration dialog box to most closely match the actual
149. ject 26 31 44 64 93 waveform building 56 work area 11 clearing 14 working with objects 14 World Wide Web 278 writing to files 125 129 X XEQ pin 56 XY Trace object 128 Data Translation Support Policy Data Translation Inc Data Translation offers support upon the following terms and conditions at prices published by Data Translation from time to time Current price information is available from Data Translation or its authorized distributor If Licensee elects to obtain support services from Data Translation Licensee must complete the Support Order Form attached hereto and submit to Data Translation the completed form along with Licensee s purchase order for support Support will only be provided for all not less than all Licensed Processors as defined in the Data Translation Software License Agreement 1 DEFINITIONS Capitalized terms used herein and not otherwise defined shall have the meanings assigned thereto in the applicable Data Translation Software License Agreement the Agreement The following terms have the meanings set forth below Enhanced Release means a new release of any Product that contains new features and may contain corrections to previously identified errors Enhanced Releases are designated in the tenths digit of the release designation e g 1 2 is an Enhanced Release from 1 1 x Maintenance Release means a new release of any Product that contains corrections to previously identified
150. l object can still retrieve all valid data from the data queue even after the channel is Done Error 2012 Acquisition is Complete for the Channel is reported only if insufficient data exists to meet the request Analog Input Acquiring a Single Analog Value Typically acquiring a single value of analog data is used when you are not concerned with a pacer clock The Get Single Value object is used to acquire one value immediately when executed It does not wait for a pacer clock tick and it does not use the Mixed Data Buffer or a data queue If you need to acquire a single analog value why use a Get Single Value object instead of a Get Data Panel object with a setting of one point The answer lies in the way the sample is acquired When the Get Data Panel object is executed the board acquires data and begins filling the Mixed Data Buffer that was set aside The data is then passed to the channel s data queue If you set the Get Data Panel object to retrieve only one sample from the data queue memory is wasted memory needlessly Another reason to use the Get Single Value object instead of Get Data Panel is if your board does not support continuous data acquisition To determine if your board supports continuous acquisition check the row labelled Continuous Operation Support in the supported options table in the board s device driver documentation A Yes in the column under the A D subsystem indic
151. l Your Data Acquisition Board To use DT VPI ensure that a data acquisition board from Data Translation is installed Refer to the manual shipped with your board for information on installing the hardware Then to perform the data acquisition examples in this manual you must connect an external function generator or other signal source to your Data Translation data acquisition board An oscilloscope if available can be used to display the output of the data acquisition board but is not required The following steps outline how to make these specific connections For more information on connecting external input and output devices consult your data acquisition hardware manual Connecting the Screw Terminal Panel To connect the screw terminal panel to your installed data acquisition board simply plug in the cable provided with the screw terminal panel as described in the following steps your hardware user manual and or screw terminal panel user manual has more information 1 Insert one end of the cable to the J1 connector on the data acquisition board 2 Insert the other end into the J1 connector on the screw terminal panel Chapter 1 Connecting a Function Generator for Input To connect a function generator or other signal generator to the screw terminal panel perform these steps 1 Attach the high side positive red or white to the screw terminal panel s channel 0 2 For differential inputs attach the l
152. ld Set Field and Sequencer objects and in I O transaction objects Feature An item on a menu that you select to cause a particular action to occur for example to open a file or to get a particular object Feedback A continuous thread path of sequence and or data lines that uses values from the previous execution to change values in the current execution Flow See Data Flow and Execution Flow Glossary Frequency Source Either an on board oscillator or a user supplied signal that provides a clock used in data acquisition Function The name and action of objects where the output is a function of the input These objects are located under Math or AdvMath menus and may be used in the Formula object For example sqrt x is a function is not Global Variable A named variable that is set globally and which can be used by name in any context of a VEE program For example a global variable can be set with Set Global in the root context of the program and can be accessed by name with Get Global or from certain expressions within the context of a UserObject However a local variable with the same name as the global variable takes precedence in an expression Grayed Feature A menu feature that is displayed in gray rather than black indicating that the feature is not active or not available Group Window A group window in Microsoft Windows is a window that contains icons for a group of applications Each icon starts an ap
153. le exists You should see some value in the data container on the output terminal as shown in Figure 48 ND Contg 5 Contes wc honbee Mame E Mode Data Container lvorredcn wm ee CRD cance Sape Seala Figure 48 The Output Terminal on the A D Config Object after It Is Run 90 Analog Input Starting an Analog Input Acquisition There are several ways to start analog data acquisition and the easiest way is to do nothing By default the A D Config object is set to start acquisition automatically when a Get Data Panel or Get Data Function object executes Another way to start acquisition on the hardware is to use the Start Acq object This object is different than the VEE Start object in that it starts a subsystem on the data acquisition hardware and does not start the execution of a VEE thread If you do not want analog input to start automatically when the Get Data Panel or Get Data Function executes include a Start Acq object before the Get Data Panel or Get Data Function object The Get Data Panel and Get Data Function objects start acquisition automatically only the first time If you stop acquisition and want to start it again you need a Start Acq object 91 Chapter 4 Acquiring Data from a Single Channel The simplest data acquisition program acquires a specified number of samples from a single channel DT VPI example program ADSIMPLE VEE in the Examples Dataacq directory i
154. lecting an output type 153 specifying a subsystem handle 154 starting an operation 155 analog to digital conversion xii ASCII file format 133 ATLABFIL VEE example program 246 B breakpoints 226 Build Waveform object 56 building a waveform 56 burst mode 104 108 142 162 configuring 105 166 optimizing analog output 183 using when writing data to file 131 bus master 195 buttons Configure 45 52 62 68 71 Cut 55 71 Delete Line 38 73 74 Line Probe 26 minimize 18 New 43 60 Open 70 Print 36 Run 33 Save 36 54 58 65 69 77 Show Data Flow 25 Index Show Execution Flow 26 Step 226 Stop 48 54 69 97 C C T Config object 209 CAL2801 VEE example program 246 CAL2812 VEE example program 246 CAL2821 VEE example program 246 CALCJC VEE example program 246 Calculate Actual Rates 142 183 Call Function object 229 changing object parameters 34 changing the configuration 70 changing the title of an object 20 channel list 83 92 149 disabling automatic build of 138 channel type 230 channel types 87 channel gain list entries 271 channels states of 100 162 writing to a file 133 clock configuring 88 configuring C T as 210 external frequency 170 204 208 source 170 204 208 using counter timer as 209 Close Subsystem object 122 142 183 CNTEVENT VEE example program 246 COHERENCE VEE example program 246 collecting data 55 Collector object 55 CompensationVolts 242 Configure button 45 52 62 68 7
155. lick anywhere on the object except in text edit boxes and hold down the mouse button An outline of the object appears while you drag the mouse 2 Move the outline to the middle of the work area while continuing to hold the mouse button down 3 Release the mouse button The object jumps to the new location Selecting the Object Menu Each object has an object menu which enables you to change attributes 15 Chapter 2 such as the size position and title of the object Also you can get online help for the specific object from the object menu To select the object menu perform these steps 1 Position the mouse over the object 2 Click the right mouse button The object menu appears as shown in Figure 6 ee inin iea Fumton D pe Frquenty M Dro Time Span Hele Aum Poets E Popga ee Figure 6 The Function Generators Object Menu Now you can click one of the object menu choices to perform the action you desire To make the object menu disappear click an empty area outside the menu Copying an Object To copy the Function Generator object and save it in a buffer for pasting late perform these steps 1 Select the object 16 2 Click the Copy button M The object goes to a buffer for pasting later It is not deleted from the work area Each time you use Copy or Cut whatever is in the buffer is overwritten If it is running stop the program before cutting or copying
156. licking the Cut button on the tool bar _ 2 Select the Until Break object and cut it as well 3 Select Flow C gt Repeat C gt For Count and place the For Count object in the same location that the Until Break was in 4 Change the value in the For Count object to 100 5 Select Data gt Collector and place the Collector object below and slightly to the right of the Get Single Value object 6 Double click the Collector object to open it 7 Connect the data output pin from the Get Single Value object to the data input pin on the Collector object 8 Connect the sequence output pin from the For Count object to the XEQ data input pin on the Collector object 55 Chapter 3 The XEQ read execute pin is a ping used to cause the Collector object to execute We want the Collector object to collect when all 100 samples have been acquired Therefore when the For Count object is done looping its sequence output pin activates causing a ping on the Collector object s XEQ pin 9 Connect the For Count object as shown in Figure 28 Po Cami 100 AD Ce Configure a Subir E 1 Binge nteper f corset Date Output Sape E nei Dim Array iL Figure 28 Changing the SINGLE VEE Program Step 7 Build a Waveform You are nearly done Once it has been collected in the Collector object the data is stored in a one dimensional array To transform this array into a wavefo
157. litude Input 40 Step a Run sags eect E end E E oe ses ed iri 41 Lesson 3 Acquire Analog Data 0 0000 cece eee 43 Step 1 Gather the Equipment 0000 43 Step 2 Add the Objects 0 eee eee eee 44 Step 3 Configure the A D Subsystem 45 Step Runt cit cae ies he ae aa Ue 47 Contents Step 5 Acquire Continuously 0 000000 00 48 Step 6 Save Your Program 6 e eee eee 49 Lesson 4 Acquire with Get Single Value 50 Step 1 Gather the Equipment 00 50 Step 2 Add the Objects 0 eee eee ee eee onl Step 3 Configure the A D Subsystem 52 Step 4s RUNN cainii ee Aig cette N su oaals 53 Step 5 Save Your Program 00 cece eee ee 54 Step 6 Collect the Data 0 cece eee eee eee 55 Step 7 Build a Waveform 000 c cece eee eee 56 Step 8 Save and Run n nuansa asunaren rnrn rrena 58 Lesson 5 Output Analog Data n asase sssr renra 60 Step 1 Gather the Equipment 00006 61 Step 2 Add the Objects i ccisccs cece nannaa 61 Step 3 Configure the D A Subsystem 62 Dtep 4s Runs ieca inet ge 4 stan a aun eu niece eit 64 Step 5 Save Your Program 6 e eee cece eee 65 Lesson 6 Digital Input and Output 0004 66 Step 1 Gather the Equipment 00000 66 Step 2 Add
158. lock period is divided evenly between high and low 50 In Figure 102 the pulse type is Low to High and the duty cycle setting is 30 205 Chapter 8 active pulse width k IJLILILIL pc total clock period Figure 102 A Signal Generated by the Counter Timer with a Low to High Pulse Type and a Duty Cycle Setting of 30 Gate Types If the gate source is None the counter timer operation is enabled immediately in software If the gate source is External one of the following gate types may be available High Level enable the counter timer operation when the gate signal is high disable the counter timer operation when the gate signal is low Low Level enable the counter timer operation when the gate signal is low disable the counter timer operation when the gate signal is high Rising Edge start and the continue counter timer operation on the rising edge of the gate signal Falling Edge start and continue the counter timer operation on the falling edge of the gate signal Figure 103 shows a signal generated by a counter timer operation using a low to high pulse type and a duty cycle of 30 enabled by an external high level gate 206 Using Counters and Timers aclive pulse widih k output o TOIL o total clock period enable hightewe gate input fexternal trigger disable Figure 103 A Signal Generated by the Counter Timer Note Some gate types may not be supported by y
159. lt file name gt has a bad header The file header is not a data acquisition file header See Appendix C for more information Data width in file lt file name gt does not match device The data width specified by the file header is not the same as the data width required by the subsystem Resolution in file lt file name gt does not match device The resolution specified by the file header is not the same as the resolution required by the subsystem Data encoding in file lt file name gt does not match device The data encoding in the file header is not the same as the data encoding required by the subsystem Voltage range or gain in file lt file name gt does not match device The voltage range in the file header as determined from minvolts and maxvolts is not the same as the range required by the subsystem System error opening file lt file name gt Generic error could be anon DOS disk a bad file sector or access denied for example The file lt file name gt is already open The file is open and cannot be shared Close the file File lt file name gt has an illegal size Partial samples are not allowed 2051 2052 2053 2054 2055 2056 2057 2058 Requested Rate exceeds the maximum throughput of the Counter Timer device Choose a slower rate Consult your data acquisition hardware manual for maximum rate information Requested Rate is less than the minimum throughput of the Counter Timer devic
160. m a data type that contains less information to one that contains more information See also Data Type and Demote Propagation The rules that objects and programs follow when they operate or run See also Data Flow 289 Glossary 290 Pull Down Menu A menu that is pulled down from the menu bar when you position the pointer over a menu title and click the left mouse button Radio Button A diamond shaped button in VEE dialog boxes that allows you to select a setting that is mutually exclusive with other radio buttons in that dialog box To select a setting click on the radio button To remove the setting click on another radio button in the same dialog box Record A data type that has named data fields which can contain multiple values Each field can contain another Record container a Scalar or an Array The Record data type has the highest precedence of all VEE data types However data cannot be converted to and from the Record data type through the automatic promotion demotion process Records must be built unbuilt using the using Build Record and UnBuild Record objects Restore To return a minimized window or an icon to its full size as a window or open view by double clicking on it Run To start the objects on a program or thread operating Sample 1 A representation of an analog signal obtained by looking at single values in the signal The values are close enough together in time to accurately recreate the s
161. minvolts Real64 maxvolts Real64 numchannels Int16 2 bytes specifying the header size in bytes This number includes the total size of the channel gain list entries as well 2 bytes specifying the version of the file header Changed for DT VPI 4 0 40 bytes specifying the board name as defined by the user when the driver was installed The board name is a null terminated ASCII string 40 bytes specifying the subsystem name The subsystem name is a null terminated ASCII string 2 bytes specifying the size of each data sample in bytes 2 bytes specifying the resolution of the board in bits typically 12 or 16 2 bytes specifying the encoding of the data A value of 0 is binary encoding and a value of 1 is twos complement encoding 8 bytes specifying the minimum voltage of the voltage range 8 bytes specifying the maximum voltage of the voltage range 2 bytes specifying the number of channels in the channel gain list 269 Appendix C 270 frequency Real64 timedate Real64 retriggerfreq Real64 8 bytes specifying the aggregate clock rate 8 bytes specifying the time and date the file was created The value is the number of seconds since 00 00 hours 1 January 0001 AD given in UTC 8 bytes specifying the retrigger rate if triggered scan mode is used Otherwise the value is zero Channel Gain List Entries These channel gain list entries are repeated numchannels times channel Int16 2 by
162. mory use 108 169 menu bar 10 Mixed Data Buffer 97 99 108 127 161 modifying a program 38 71 MONITOR VEE example program 241 248 moving objects 15 MULITFILE VEE example program 248 MULITI VEE example program 248 multi channel file configuration 135 MULTIFILE VEE example program 138 N New button 43 60 Noise Generator object 38 40 Nyquist theorem 47 84 O object menu pictured 16 selecting 15 objects A D Config 26 44 51 81 Acq Status 100 122 142 173 adding 14 31 44 51 61 67 adding an error output pin to 122 adding terminals 23 Alloc Real 75 Allocate Array 173 Build Waveform 56 C T Config 209 Call Function 229 changing parameters 34 changing the title 20 changing object views 18 Close Subsystem 122 142 183 Collector 55 connecting 23 32 control bar 18 copying 16 Counter 199 cutting 17 D A Config 61 147 Delay 199 deleting 17 deleting terminals 24 Digital In Config 67 187 Digital Out Config 187 dragging 15 duplicating 16 Enum 107 Execute Program PC 139 FFT x 99 For Count 55 103 127 135 Formula 200 From File 129 177 Function Generator 14 31 61 151 157 Get C T Frequency 118 171 Get C T Measure Duration 118 171 Get C T Mode 118 171 Get C T Pulse Width 118 171 Get Channel Buffer Size 117 170 Get Channel Filter 118 171 Get Clocking 117 170 Index Get Data Function 142 199 Get Data Mode 118 171 Get Data Panel 26 44 9
163. n count is 8 enter a channel rate of 160 Hz Assume for example that you want to sample three channels 0 1 and 2 each time an external trigger pulse occurs The initial trigger is an external trigger the retrigger is an internal trigger Trigger pulses are expected 10 times per second or 10 Hz and you want the period between each channel in the scan to be 0 1 ms or 10 kHz Lastly you want to acquire seven samples for each channel in the scan Set up the triggered scan as follows e Inthe A D Config dialog box Add channels 0 1 and 2 to the Current Channels List and Set the channel rate to 70 Hz the expected trigger frequency multiplied by the multi scan count e Inthe A D Timing dialog box Set the Trigger Source to External Set the Trigger Mode to Triggered Scan Set the Re trigger Source to Internal Set the Sample Clock Frequency to 10 kHz and Set the Multi scan count to 7 Analog Input After two trigger pulses the order in which the channels were sampled in this example appears as shown in Figure 63 Sample Clock Channels 0 1 and 2 are acquired 7 Frequency 10 kHz times per scan multi scan count m 012012012012012012012 012012012012012012012 External Trigger Internal Retrigger Occurs Occurs Channel Rate 70 Hz Retrigger Clock Rate Figure 63 Channel Sampling Order Example on Disk The TRIGSCAN VEE example program in the Examples Dataacq directory shows how to
164. nal Input or Type Description Output hSubsys input Int32 subsystem handle Ret Value output Int32 subsystem handle Resolution input Int32 number of bits of resolution 237 Chapter 10 238 dtv GetSingleValueEx dtv GetSingleValueEx allows you to retrieve a single value from a subsystem on a specified channel using a specified gain Table 24 dtv GetSingleValueEx Terminal Input or Type Description Output hSubsys input Int32 subsystem handle Channel input Int32 subsystem channel Gain input Real Gain hSubSys output Int32 subsystem handle Value output Int32 single raw data value dtv PutSingleValueEx dtv PutSingleValueEx allows you to output a single value on a specified channel using a specified gain Table 25 dtv PutSingleValueEx Terminal Input or Type Description Output hSubsys input Int32 subsystem handle Channel input Int32 subsystem channel Gain input Real Gain hSubSys output Int32 subsystem handle Value output Int32 single raw data value Advanced Functionality dtv GetTriggerThreshold dtv GetTriggerThreshold returns the current trigger threshold level of the subsystem pointed to by hSubsys Table 26 dtv GetTriggerThreshold Terminal Input or Type Description Output hSubsys input Int32 subsystem handle Ret Value output Int32 subsystem handle Threshold output Int32 trigger threshold le
165. nalog data or outputting analog data Each channel is connected to an external analog device which either provides a signal to be acquired or accepts an analog signal The channels are always used in order from lowest to highest Checkbox A recessed square box on VEE menus and dialog boxes that allows you to select a setting To select a setting click on the box and a checkmark appears in the box to indicate a selection has been made To cancel the setting simply click on the box again Click To press and release a mouse button quickly Clicking usually selects a menu feature or object in the VEE window See also Double Click and Drag Compiled Function A user defined function created by dynamically linking a program written in a programming language such as C into the VEE process For Windows the user must create a DLL Dynamically Linked Library file and a definition file The Import Library object attaches the shared library or DLL to the VEE process and parses the definition file declarations The Compiled Function can then be called with the Call Function object or from certain expressions See also User Function Glossary Component A single instrument function or measurement value in a VEE instrument panel or component driver For example a voltmeter driver contains components that record the range trigger source and latest reading See also Component Driver Driver Files State and Instrument Panel Composite Data
166. need a Put Data Panel object for each configured channel For example Figure 84 shows what the DACONT VEE example program in the Examples Dataacq directory looks like mgm l piwan Trace al i y 5 Figure 84 Example on Disk DACONT VEE A one to one correspondence exists between the number of Put Data Panel objects and the number of channels selected in the D A Configuration dialog box For this example the D A Config object was configured only for channel 0 as shown in Figure 85 159 Chapter 5 Edi Channel Ow Cheare Gan Fishes He _ Beno Cyrent Channels Chearel Gan Piste Hel T Capian acua reas Figure 85 Configuration for One Channel What s Really Going On Figure 86 illustrates how data is stored in memory and then retrieved by DT VPI Data Queues Mixed Data Buffer Ch 10 Put Data Panel gt one Two seconds of data output data for all configured 3 channels CRITICAL THRESHOLD 5 sec Mixed Data Buffer must have at least the critical threshold amount of data to continue Figure 86 Acquired Data is Stored in Memory then is Retrieved by DT VPI 160 Analog Output Now let s look at this program to learn the how DT VPI handles data e When you click Run the D A Config object initializes the board and sets up the channel list Enough memory for two seconds of data for all channels is set aside as the Mixed Data B
167. nfigure a subsystem on a data acquisition board The subsystem configuration objects are e A D Config e D A Config e Digital In Config e Digital Out Config e C T Config Glossary Subsystem Handle A number identifying the subsystem of interest to data acquisition objects After a subsystem configuration object is run a handle for that subsystem exists This handle is passed as input to any data acquisition object that needs to interact with that subsystem Terminal The internal representation of a pin that displays information about the pin and the data container held by the pin Double click the terminal to view the container information Thread A set of objects connected by solid lines in a VEE program A program with multiple threads can run all threads simultaneously Title Bar The rectangular bar at the top of the open view of an object or window which shows the title of the object or window Tool Bar The rectangular bar at the top of the VEE window which provides buttons to control VEE programs open and save files and many other handy tools Transaction The specifications for input and output I O used by certain objects in VEE These include the To File From File and Sequencer objects Transactions appear as English like phrases listed in the open view of these objects User Defined Function VEE allows two types of user defined functions the User Function and Compiled Function Triggered Scan A kind
168. ng a Single Analog Value 00004 101 Acquiring a Burst of Data 0 000 e eee eee 104 Acquiring Pre Trigger Data 0006 cece eee eee eee 109 Acquiring Data Using a Triggered Scan 0 112 Changing the Subsystem Configuration 5 n7 Handling Acquisition Errors 0 0 0 c cece eee ee 121 Sending Data to a Disk File 6 cece cece eee 125 Sending Data Through DDE 0 00 c eee eee 139 Optimizing Analog Input 0 0 asnus nern eee eee 142 79 Chapter 4 80 This chapter discusses how to control your data acquisition hardware to perform analog input It includes information on configuring the channel list setting the sampling rate and gain and using an external clock or trigger This chapter also includes many example programs and explanations of using the data acquisition objects provided by D TVPI You will learn how to create programs to e Acquire data and display it e Acquire data on several channels e Acquire data continuously e Acquire a single value repeatedly e Acquire a known number of samples or acquire for a known duration e Acquire data before a trigger event e Acquire scans of data when a trigger occurs e Handle errors and e Send data to a file or to another application through DDE Analog Input Connecting External Sensors Before you can acquire analog data you need to connect your ext
169. nization of the ports use the advanced function dtv GetResolution in a Call Function object see page 237 To change the organization of the ports use the function dtv SetResolution Select a Digital In Config object to specify that you want to use all available digital lines or one port for input Select a Digital Out Config object to specify that you want to use all available digital lines or one port for output When you click the Configure button on a Digital In Config or Digital Out Config object you do not see a dialog box to set up a channel list A channel list is inappropriate when working with digital input and output devices Instead the Select Device and Subsystem dialog box appears as shown in Figure 96 187 Chapter 6 If you have more than one device installed in your computer then select a device from the drop down list under Device Name Once a board is selected DT VPI indicates whether the digital lines are organized as one port or more than one port If they are organized as one port then DIN Unit 0 appears grayed out under SubsystemTo Use However if they are organized as more than one port then DIN Unit 0 is not grayed out and you can choose among the ports Select Device and Subsystem x Sub syitern Type aie Lr A ema Dran mE Heip Bub aysha io wc Figure 96 The Select Device and Subsystem Dialog Box 188 Digital Input and Output Acquiring a Single Digital Value Dig
170. nnel and still provide gap free data acquisition Double Click To press and release a mouse button twice in rapid succession Double clicking is usually a short cut to selecting and performing an action For example double clicking on a file name from File gt Open will select the file and open it 283 Glossary 284 Drag To press and continue to hold down a mouse button while moving the mouse Dragging moves something for example an object or scroll slider Entry Field A field that is typically part of a dialog box or an editable object and which is used for text entry An entry field appears recessed For example the open view of the For Range object has entry fields where you type values that specify the beginning ending and step values Error Message Information that appears in an error dialog box explaining that a problem has occurred Error Pin A pin that traps any errors that occur in an object Instead of getting an error message the error number is output on the error pin When an error is generated the data output pins are not activated Execute The action of a program or parts of a program running Execution Flow The order in which objects operate See also Data Flow Expression An equation in an entry field that can contain the input terminal names and any Math or AdvMath functions An expression is evaluated at run time Expressions are allowed in Formula If Then Else Get Values Get Fie
171. nnelType 230 dtv SetCriticalThreshold 163 231 dtv SetMixedBufferSize 236 dtv SetResolution 190 192 237 dtv SetTriggerThreshold 239 ThAverage 242 VoltsToDegrees 243 aggregate sampling rate 117 aliasing 84 ALLCHAN VEE example program 138 246 Alloc Real object 75 Allocate Array object 173 Allow Gaps data mode 99 142 161 183 295 Index 296 analog input acquiring a burst of data 104 acquiring a single value 101 acquiring data continuously 96 acquiring data from a single channel 92 acquiring data from multiple channels 94 building a channel list 83 configuring 81 displaying data 93 external trigger 107 filtering a signal 85 optimizing 142 pre trigger data 109 running with analog output 194 selecting a board 82 selecting a clock 88 selecting a gain 86 selecting a sampling rate 84 selecting a trigger 88 selecting an input range 87 selecting an input type 87 sending through DDE 139 specifying a subsystem handle 89 starting an operation 91 triggered scan 112 using C T as a trigger 212 using C T signal as pacer clock 209 writing to disk files 125 129 analog output burst mode 166 configuring 147 configuring the channel list 149 connecting external devices 147 continuous output 159 critical threshold 162 163 optimizing 183 outputting a single value 164 overview 146 reading from disk 177 running with analog input 194 selecting a board 148 selecting an output range 153 selecting an output rate 150 se
172. nslation s then current rates Specialized Application Support Charges for labor travel time transportation subsistence and materials during normal business hours excluding holidays observed by Data Translation The troubleshooting of faulty Licensee programming logic may also be subject to Specialized Application Support Charges and is not covered under this Support Policy Direct authoring or development of customized application code is not provided hereunder but may be available on a per call basis upon payment of Specialized Application Support Charges 4 LICENSEE S OBLIGATIONS Licensee agrees a that the Designated Contact persons identified on the Support Order Form or such other replacement individuals as Licensee may designate in writing to Data Translation shall be the sole contacts for the coordination and receipt of the Support Services set forth in Section 2 of this Support Policy b to maintain for the term of the support an internet address for electronic mail communications with Data Translation c to provide reasonable supporting data including written descriptions of problems as requested by Data Translation and to aid in the identification of reported problems d to install and treat all software releases delivered under this Support Policy as Software in accordance with the terms of the Agreement and e to maintain the Agreement in force and effect 5 TERM AND TERMINATION 5 1 Term For each Produ
173. nsures that the loop starts after the analog input subsystem is configured and has a subsystem handle Note that the subsystem handle is sent to each of the Get Data Panel objects as input On each cycle the Until Break object pings the sequence in pin of the Get Data Panel object for channel 0 which reads the specified number of samples and then alerts the next Get Data Panel object that it is OK to do so as well by a sequence ping When all of the Get Data Panel objects have executed and the data has been graphed the loop repeats until you stop the program by clicking the Stop button E on the tool bar The subsystem continues acquiring data for a few moments more until the data queues and Mixed Data Buffer is filled 97 Chapter 4 What s Really Going On Figure 55 illustrates how data is stored in memory and then retrieved by DT VPI Mied Daia Butter fend seconds vaarti of dete acquired for all cewfigqured channels deta Figure 55 Acquired Data Stored in Memory then Retrieved by DT VPI Now let s look deep into the program to learn how DT VPI handles data e When you click Run the A D Config object initializes the board and sets up the channel list Enough memory for two seconds of data for all channels is set aside as the Mixed Data Buffer The subsystem is in Ready state e When the Get Data Panel object is executed acquisition begins automatically the subsystem is running All three channels
174. nternally supplied Internal using the list box next to Source Select Triggered Scan from the list box next to Mode and select the Re trigger Source this trigger source retriggers the scan once it is started Tamara BEDE Ei Source nens Grimma Goch Foaquence He E Heo ddi Tigga iua Esana Torir Esate Hah Troed Sem F Triope ees Sample Clock Frequency Ha _a fin 1 T Catalase ponas gi Figure 62 Setting Up Triggering for Triggered Scan Then set the Sample Clock Frequency which is the frequency between channels in the scan For example suppose you want to sample two channels 1 ms apart each time a trigger pulse is received The sample clock rate is 1 channel per 1 ms or 1000 cycles 1000 ms this corresponds to a sample clock frequency of 1000 Hz 113 Chapter 4 114 If you want to acquire several samples from several channels each time a trigger or retrigger pulse occurs you can also set the multi scan count For example if you want to acquire eight samples from two channels each time a trigger or retrigger occurs and perhaps average these samples later set the multi scan count to 8 Note that if you specify a multi scan count ensure that the channel frequency that is entered in the Rate box of the A D Config dialog box is the result of the expected trigger frequency multiplied by the multi scan count For example if you expect a trigger every 20 Hz and the multi sca
175. nters and Timers describes how to configure the counter timer subsystem and use it as a clock a trigger to count events and to measure a frequency Chapter 9 Developing Programs for VEE RunTime provides some tips for developing programs that can be used in different hardware configurations with VEE RunTime Chapter 10 Advanced Functionality details three methods of accessing DT VPI s advanced functionality calling advanced functions in a Call Function object using the unsecured versions of the data acquisition UserObjects and integrating specialized thermocouple linearization UserFunctions into your own programs Appendix A Example Programs describes the examples provided with DT VPI Appendix B Error Codes describes the error codes that DT VPI can return Appendix C File Formats contains reference information about the file headers used in DT VPI xvii About this Manual xviii e Appendix D Product Support describes how to obtain technical support should you require it e An index completes this manual Conventions Used in this Manual The following conventions are used in this manual When information applies to both VEE Pro and VEE OneLab the term VEE is used VEE provides the fundamental visual programming environment The term DT VPI refers to the component from Data Translation DT VPI provides objects used to specifically control data acquisition hard
176. o learn about these aspects of programming in VEE you need to read through the user manuals that are supplied with VEE The manual is organized as follows e Chapter 1 Installing DT VPI describes how to install DT VPI and refers you to your data acquisition hardware manual if you have not yet installed your hardware e Chapter 2 Quick Start covers the basics of using objects If you are already familiar with VEE then you can skip this chapter e Chapter 3 Your First Program guides you through several lessons on using the data acquisition objects in DT VPI e Chapter 4 Analog Input describes how to configure the A D subsystem and create programs to acquire analog data Many different types of analog input are discussed such as continuous input burst mode single value as well as sending data to disk and through DDE e Chapter 5 Analog Output describes how to configure the D A subsystem and create programs to output analog data Continuous burst mode and single value output are discussed as well as how to set up the Function Generator object to generate data for output About this Manual Chapter 6 Digital Input and Output explains how to configure the digital input and output subsystems and how to acquire and output single digital values Chapter 7 Simultaneous A D and D A describes what you need to know to run two subsystems simultaneously Chapter 8 Using Cou
177. object instead of the Get Data Panel object The Get Data Function object runs more efficiently because it is a function call not a UserObject Use the Write to File feature if you need to acquire and store data fast over 10 kHz Writing data directly to disk uses a binary format for the unprocessed data To read the data use DT VPI example program DTVFILE VEE which uses the information in the file header to process the raw data values to voltages When using 16 input channels or more use the multi channel feature to write data for all the channels to a single file Analog Input e If you are collecting data quickly increase the number of points each Get Data Panel object or Get Data Function object should retrieve from memory A seconds worth of data is typically an appropriate amount e Do not type 0 in the Points edit box of aGet Data Panel object If you enter 0 then DT VPI retrieves all currently acquired data from memory If you are acquiring data quickly then depending on how much memory you have in your system the amount of data may be too much for DT VPI to handle Generally you should not retrieve more than 500 000 points at a time 143 Chapter 4 144 Analog Output Connecting External Devices 000 cece ee eee 147 Configuring for Analog Output 00 000008 147 Starting an Analog Output 0 0 0 cece eee eee eee 155 Outputting Analog Data from a Single Chann
178. of 1536 samples An error is raised in this situation as well because the Get Data Panel object is trying to retrieve more data than is stored in the data queues To correct this error either reduce the loop to two iterations so the total number of samples retrieved is exactly 1024 or increase the number of samples in the Burst mode configuration to 1536 Analog Input Acquiring Pre Trigger Data Sometimes you want to acquire data before a trigger event occurs This type of operation is called pre trigger acquisition For example assume you are performing in vehicle testing and you want to measure data on channel 0 before the car crashes and plot the pre trigger data on a strip chart Figure 59 shows how the program might appear we Canig E Cooipre haa j i Gan Pre Trigger Dota Pargi a E l Linii ire ak i sul i bubs Lit om a na iws na i Thal oa E oa Sheps 1 A Tea Figure 59 Pre Trigger Mode Configuration 109 Chapter 4 Configuring for Pre Trigger Acquisition To acquire pre trigger data first set up the acquisition as you normally would specifying the channel parameters for your application using the A D Config dialog box Then click the Timing button in the A D Advanced Configuration dialog box shown in Figure 60 In the Trigger section the lower part of the dialog box select a Pre trigger Source Note that the available pre trigger sources depend on the capabilities of your
179. of data acquisition where data from several channels are sampled each time a trigger pulse is received The data for each channel is in the same time domain over which you have control See Chapter 4 for more information UserFunction A user defined function created from a UserObject by selecting Make UserFunction from a UserObject s user menu The UserFunction exists in background but provides the same functionality as the original UserObject 293 Glossary 294 You can call a UserFunction with the Call Function object or from certain expressions A UserFunction can be created and called locally or it can be saved ina library and imported into a VEE program with Import Library See also Compiled Function and UserObject User Interface The part of an application that permits a user and the application to communicate with each other to perform certain tasks VEE uses a graphical user interface which includes windows menus dialog boxes and objects UserObject An object that can encapsulate a group of objects to perform a particular purpose within a program A UserObject allows you to use top down design techniques when building a program and to build user defined objects that can be saved in a library and reused View See Detail View Icon Open View and Panel View Wait See Sleep Window A rectangular area on the screen that contains a particular application program such as VEE Work Area The area within th
180. of the base file name For example if your post trigger file name is aindata dtv the pre trigger data file name is aindatap dtv Likewise if your post trigger file name is chnOdata dtv the pre trigger data file name is chnOdatp dtv Note You can specify the post trigger file name only To retrieve pre trigger data use the Get PreTrigger Data Panel or Get PreTrigger Data Function object To retrieve post trigger data use the Get Data Panel or Get Data Function object 111 Chapter 4 Acquiring Data Using a Triggered Scan Sometimes you want to acquire data on several channels and have each channel sampled whenever a trigger pulse is received This type of data acquisition is called triggered scan First configure the input channels as you normally would setting the channel s rate to the frequency at which the trigger pulse is expected in triggered scan mode this is the re triggering rate For example if the trigger is expected 70 times per second set the channel s rate to 70 Hz as shown in Figure 61 Configuration DT3010 7 Analog Input 0 Figure 61 Setting Up the Channels and the Channel Rate for Triggered Scan 112 Analog Input To configure a trigger and retrigger click the Timing button in the A D Advanced Configuration dialog box shown in Figure 62 In the Trigger section the lower part of the dialog box indicate whether the initial trigger is externally supplied External or i
181. on of the A D Configuration dialog box When execution passes to the Get Data Panel objects the subsystem is running but does not start acquiring data because it is waiting for an event to trigger it When the hammer starts falling a TTL signal is output our external trigger and the subsystem begins acquiring data As usual the data is stored in the Mixed Data Buffer and then pulled out sorted by channel and placed in the data queues When each data queue has exactly 1024 samples in it the acquisition stops on that channel When acquisition stops on all channels the subsystem stops The Get Data Panel object retrieves the number of samples specified in its Points edit box and passes this data to other objects in the program Note Because only enough memory is set aside for the specified number of samples or number of seconds of data in the data queues using burst mode results in more efficient use of memory Suppose you set the Get Data Panel object to retrieve 1025 samples and enable burst mode for 1024 samples Because the Get Data Panel object tries to retrieve more data than has been acquired error 2012 The acquisition or output is complete occurs To correct this error set the Get Data Panel object to retrieve 1024 samples Suppose further that burst mode is set to acquire 1024 samples again but the program uses a looping construct whereby the Get Data Panel object retrieves 512 samples three times for a total
182. orming the following steps 1 Click the Save button E By default VEE saves your files to the MY DOCUMENTS VEE PROGRAMS directory The Save File dialog box shown in Figure 16 appears 36 Your First Program Sven VEE Pogan a i el f mal Flepams fengieves Saves as hype HEE Fioganre vea Cancel Figure 16 Saving a VEE Program to a File 2 Enter a name for example SIMPLE and click Save VEE automatically adds the extension VEE to the file name Note To re save your program to the same file name select File gt Save or click fal or press GS at any time It is a good idea to save your file frequently while you are developing a program 37 Chapter 3 38 Lesson 2 Modify Your Simple Program 5 minutes In Lesson 2 you will modify the program you created in Lesson 1 You will add noise to the waveform and then add an adjustable amplitude input to the noise Restart VEE if necessary and open the program from Lesson 1 SIMPLE VEE by selecting File o gt Open Step 1 Make Some Noise Add some noise to the waveform Click the Delete Line button on the tool bar l Click the connection between the Function Generator object and the Waveform Time object The connection disappears Minimize the Function Generator object to an icon To do this click the minimize button in the upper right corner of the object Select Device C gt Virtual Source C gt Noise Gener
183. our hardware Refer to the supported options table in your hardware device driver documentation Delay and Pulse Width Delay and Pulse Width are an alternative to using Frequency and Duty Cycle to define the shape of the counter timer output and are typically used with one shot mode Delay is the amount of time in milliseconds ms between the beginning of the counter timer output and the active portion of the pulse The pulse width is the duration of the active portion of the pulse in milliseconds as shown in Figure 104 207 Chapter 8 delay pulse width pije JL Figure 104 Delay and Pulse Width of a Counter Timer s One Shot Signal Duration When the counter timer is set to measure the frequency of events pulses in a TTL signal the Duration is the total duration over which the signal is measured in seconds as shown in Figure 105 Duration 5 Lma to High events 4 High to Low events Figure 105 Measuring the Frequency of Events Clock Frequency If an internal clock source is selected then its frequency is determined by entering a value in Frequency Hz in the C T Configuration dialog box If an external clock source is selected then enable DT VPI to be aware of its frequency by entering its frequency or the closest you can estimate in the External Clock Frequency Hz edit box 208 Using Counters and Timers Using the Counter Timer as a Clock The counter timer can be used to generate a u
184. ource and enter in the desired frequency of the clock in the Frequency Hz edit box If you are using an external frequency as the clock source select External and enter the estimated frequency in the External Clock Frequency Hz edit box Indicate the pulse type High to Low or Low to High and its width in the Duty Cycle edit box If you select a gate source other than None the square wave output is generated based on the gate specified High Level Low Level Rising Edge Falling Edge Select DT DataAcq gt A D Config Now click the Configure button on the A D Config object If you have more than one data acquisition board in your computer then select the A D subsystem you want to interact with in the Select Subsystem dialog box In the A D Configuration dialog box click the Timing button Set the Clock Source to External After connecting a signal source to channel 0 and you have already connected the output from the first C T to the A D external clock input on the screw terminal panel the program is ready to run Using Counters and Timers What s Really Going On When you run this program the Start Acq object executes and starts the counter timer subsystem The counter timer begins generating a signal at the specified frequency and outputs it That signal reaches the A D subsystem s external clock input because they are connected on the screw terminal panel and analog data is acquired using the external
185. ow Gaps mode but the subsystem continues to run e When the thread finishes executing the program stops but data acquisition continues on the hardware until the Mixed Data Buffer fills Then data acquisition stops If you pause or stop the VEE program data acquisition continues until the data queues and Mixed Data Buffer fill or until a Stop Acq object is executed 99 Chapter 4 100 States of an A D Channel Since the Get Data Panel returns when it has retrieved all of the samples specified you may be interested in finding out how many samples still remain in that channel s data queue by executing an Acq Status object Acq Status also provides information about the status for the channel as shown in Table 3 Table 3 States of an A D Channel Status from Acq Channel Status Status Object Ready Subsystem is initialized but not started No data exists in memory yet Executing a Stop Acq or Set Config object returns each channel in the subsystem to Ready Running The hardware is acquiring data on the channel or awaiting an external trigger Note that the channel continues to run even after Get Data Panel retrieves its specified samples Done The channel Stopped for one of the following reasons a Burst mode finished b The data mode is Gap Free and the channel s data queue ran out of space c Hardware errors such as overrun 2008 or trigger 2006 errors occurred Note that the Get Data Pane
186. ow side negative black to channel 0 return For single ended inputs attach the low side to any signal ground Connecting an Oscilloscope for Output To connect an oscilloscope to the screw terminal panel perform these steps 1 Attach the high side positive red or white to D A 0 Out 2 Attach the low side negative black to D A 0 Ground Step 2 Install the Device Driver DT Open Layers device drivers are provided on the Data Acquisition OMNI CD that is shipped with your board Ensure that the WOM device driver for the operating system you are using is installed Refer to the manuals shipped with your board for information on installing your device driver Step 3 Install VEE Open the VEE package which is included in the box along with DT VPI Install VEE Pro or VEE OneLab following the instructions in the VEE documentation Installing DT VPI Step 4 Install DT VPI Once you have set up your computer installed the data acquisition hardware and device driver and installed VEE Pr or VEE OneLab you are ready to install DT VPI using the following instructions 1 Start Microsoft Windows 2 Insert Data Translation s DT VPI CD into an available CD ROM drive 3 Click Start located on the task bar then click Run The Run dialog box appears 4 Inthe command line text box enter D Setup exe where D is the CD ROM drive designation you are using for this installation then click OK The Install S
187. own You can enlarge the object or reduce it as much as you want Changing the Title of an Object To change the title of an object perform these steps 1 Select Edit Properties from the object menu The Edit Properties dialog box shown in Figure 9 appears 2 Type the new title and click OK To enter a new title start typing over the highlighted text When you click OK the new title appears in the title bar If you minimize the object the new title labels the icon 20 Type a new title here ft Show Tile Bar E Show Terminals eer Error Checking E Eror On Alacing om cma e Figure 9 The Edit Properties Dialog Box Note You can save time by using standard Windows editing techniques For example the left and right arrow keys move the cursor and the elet and Backspace delete letters as you would expect 21 Chapter 2 22 Understanding Pins and Terminals A single object can do little by itself However by connecting objects together with lines you can construct a VEE program The points of connection are the input and output pins Most objects have one or more of the following kinds of pins as shown in Figure 10 e Pins on the left hand side of an object are data input pins e Pins on the right hand side of an object are data output pins e The pin on the top of an object is the sequence input pin e The pin on the bottom of an object is the sequence output pin Seq
188. ows The minimize button is located at the right end of the object s title bar Change a Function Generator object from its open view to its icon by clicking once on the minimize button You can use the icon to save space in your work area To return to the open view double click the icon To change parameters the object must be in open view The two views of the Function Generator object are shown in Figure 7 Click here to iconize Function Cosine Double click to open Frequency 1000 Amplitude L Crotset oF Fune Phase beg oo Time Span 20m Num Points JRE Open view Icon view Figure 7 Open View and Icon View of an Object Changing the Size of an Object You can change the size of an object in open view or icon To change the size of an object perform these steps 1 Position the mouse pointer over the lower right hand corner of the object until you see a left angle 2 Click and drag to the desired size Or 1 Select Size from the object menu The mouse pointer becomes a left angle 2 Move this bracket as shown in Figure 8 to define the size that you want then click 19 Chapter 2 Frequency 1000 Amplitude 1 Deasa 0 Funcll Phase deg Jf oo Time Span m tum Points 256 Left angle bracket 7 Figure 8 Resizing an Object Note that this procedure is a little different than that for resizing a window Try resizing the object a few times on your
189. pen Layers Errors The following DT Open Layers errors are generated from the device driver For a description of VEE errors refer to your VEE documentation Error Description Number 0 Operation complete no error 1 Invalid subsystem capability requested 2 Illegal element type specified 3 Illegal subsystem specified 4 Insufficient DMA channels are available to perform the requested operation 5 The channel gain list size is out of range 6 Illegal channel gain list entry specified 7 The specified channel is out of range 8 Illegal channel type requested 9 Illegal encoding value requested 10 Illegal trigger source requested 11 Illegal resolution requested 12 Illegal clock source value requested 13 The specified clock frequency is out of range 14 Illegal pulse type requested 15 The pulse width is out of range 16 Illegal counter mode requested Error Number 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 Description Illegal cascade mode requested Illegal data flow requested Invalid window handle specified The requested subsystem is already in use The requested subsystem is not in use The subsystem is already running The subsystem has no channel list The subsystem has no gain list The subsystem has no filter list The subsystem has not been configured Single value operation was attempted while in continuous data flow mode or vice versa Stop issue
190. pike on the output of the counter timer Therefore if you are using the counter timer as an external clock or external trigger ensure that the Start Acq object is executed for the counter timer subsystem before starting the A D subsystem Configuring the C T as aTrigger To configure this example program click Configure on the C T Config object If you have more than one counter timer subsystem on your board select the subsystem whose output you connected to the A D external trigger input on the screw terminal panel Click OK Then set the Mode to One Shot leaving the Delay at 0 5 ms and the Pulse Width at 0 5 ms Click OK to close the C T Configuration dialog box Now click the Configure button on the A D Config object If you have more than one data acquisition board in your computer select the A D subsystem you want to use in the Select Subsystem dialog box In the A D Configuration dialog box click the Timing button Set the Trigger Source to External After connecting a signal source to channel 0 and you have already connected the output from the first C T to the A D external trigger input on the screw terminal panel the example program is ready to run 213 Chapter 8 What s Really Going On When you run this program the Start Acq object is executed which starts the delay period for the one shot pulse The Get C T Mode and Set C T Mode objects ensure that the counter timer is set for one shot mode even i
191. plication in the group Hertz Hz Samples per second For example if an analog signal is sampled 1000 times every second its sampling rate is 1000 Hz or 1 kHz Highlight 1 The colored band or shadow around an object that provides a visual cue to the status of the object 2 The change of color on a menu feature that indicates you are pointing to that feature Host To begin a thread or subthread For example the subthread that is hosted by For Count is the subthread that iterates 285 Glossary 286 Hypertext A system of linking topics so that you can jump to a related topic when you want more information In on line help systems typically hypertext links are designated with underlined text When you click on such text related information is presented Icon The small graphical representation of a VEE object such as the representation of an instrument a control or a display Interrupt A signal that requires immediate attention that may suspend a process such as the execution of a computer program An interrupt is usually caused by an event external to that process After the interrupt is serviced the process may be resumed Label The text area or name on an icon or button that identifies that object or button Library A collection of often used objects or small programs grouped together for easy access Line A link between two objects in VEE that transmits data containers to be processed See also Sub
192. put continuously e Output a single value e Output a known number of samples or output for a known duration e Change the configuration while the program is running e Handle errors and e Read data from a file or from another application through DDE Analog Output Connecting External Devices Before you can output analog data connect your device requiring analog input Your hardware manual has detailed instructions on connecting external devices Configuring for Analog Output Now it is time to start building your data acquisition program For an analog output program you need the D A Config object Select DT DataAcq gt D A Config and click Configure Table 6 directs you to the appropriate dialog box to perform various configurations These configurations are discussed in the following pages Table 6 Configuring the D A Subsystem To Configure In the D A Config Object click The D A channel list Configure Sampling output rates for channels Configure Sampling rates burst mode read from file and data mode Gap Free or Allow Gaps for channels Configure and then Advanced The output voltage range Configure and then Hardware The output channel type Configure and then Hardware The clock source Configure and then Timing The trigger source Configure and then Timing 147 Chapter 5 Selecting a Board when More than One
193. q directory demonstrates continuous retrieval of single values from a digital input subsystem Note If you need to change the resolution of the DIN or DOUT subsystem and your board supports this option you can use the advanced function dtv SetResolution See Chapter 10 Advanced Functionality for information on this function Simultaneous A D and D A Hardware SUpport ioii iad tases neniaie toned gb iniiai 195 Starting Two Subsystems Simultaneously 200 Sharing DMA Resources 0 0 0 e eee eee eee 201 193 Chapter 7 This chapter provides device specific information about running the A D and D A subsystems at the same time You will learn e Whether your hardware supports running two subsystems simultaneously and if so using which data transfer modes e How to start two subsystems simultaneously e How to prime the analog output subsystem with data and e Considerations for using the computer s DMA resources 194 Simultaneous A D and D A Hardware Support Table 9 lists the data acquisition boards from Data Translation and the combinations of data transfer methods that are supported when using the A D and D A subsystems simultaneously The data transfer methods are DMA Bus Master Single Value and Polled I O For analog input you are using the DMA transfer method when you use the Get Data Panel or Get Data Function object and check Use DMA Data Transfer in th
194. r the maximum number of open files permitted by your system Choose this mode by placing an X in the checkbox next to Multi channel File in theWrite to File section of the A D Advanced Configuration dialog box The data is always gap free Each channel s sampling rate is the same the rate is computed by dividing the aggregate rate by the number of channels Your choice of aggregate rate is determined by the data acquisition subsystem capabilities This data format uses the VEE Multi channel File Format see Appendix C for file header information In the example shown in Figure 75 three analog input channels are used 0 1 and 2 There is a Get Data Panel object for each channel and the number of points is 512 Since the For Count object loops twice the total number of points retrieved is 1024 The first channel is displayed on the XY Trace object 135 Chapter 4 136 wD Gorig Configure hiubme a i sa z F i i aae Tae l 1 Gel Data Pane 4 i Tracel Get Data Fane l a Get Data Pane Figure 75 An Example Program for Writing Three Channels to One File To configure for this example click the Configure button on the A D Config object Click the Advanced button To avoid accidentally filling up your hard disk enable burst mode by placing an X in the checkbox next to Enable in the Burst Duration section Make sure 1024 samples is selected for the burst duration 512 points 2 loops Enabl
195. ram is ready to run Step 8 Save and Run To save and run your program perform these steps 1 Save your program by clicking the Save button on the tool bar 2 Use the same settings on the external function generator as you did before a square wave at 100 Hz 3 Run the program Acquiring 100 single values takes a few moments so be patient The output is displayed in the Waveform Time object as shown in Figure 30 Your First Program Treel Budd Waveform Figure 30 Output after Acquiring Single Values and Building a Waveform 4 Save your program again by clicking the Save button on the tool bar fal 59 Chapter 3 Lesson 5 Output Analog Data Digital data can be converted to analog data and with the aid of your data acquisition hardware output to external analog devices such as an oscilloscope You can use digital data generated internally in VEE or use acquired analog data that has been converted to digital values by your data acquisition hardware In Lesson 5 you will create a new program that generates some data using a Function Generator object displays the signal in VEE and outputs an analog signal to an oscilloscope if one is connected Restart VEE if you have quit If VEE is already running clear the work area by clicking the New button on the tool bar pa Note If your board does not support continuous output you cannot use the Put Data Panel object when outputting data
196. rdware to find out if the analog input and output subsystems support gap free data transfers with zero one or two DMA channels If your board supports OLSSC_SUP_GAPFREE_NODMA you can run all subsystems simultaneously without using any DMA resource leaving them available for other devices in your system If your board supports OLSSC_SUP_GAPFREE_SINGLEDMA for A D or D A you can run that subsystem with one DMA channel If it supports OLSSC_SUP_GAPFREE_DUALDMA for A D or D A you need two DMA channels to run that subsystem in continuous gap free mode Using Counters and Timers Terminology serdari sence tobceig eth ada aa 205 Using the Counter Timer as a Clock 00006 209 Using the Counter Timer as a Trigger 05 212 Using the Counter Timer to Count Events 216 Using the Counter Timer to Measure Frequency 218 Optimizing Counter Timers 0 000 cece 221 203 Chapter 8 204 inkerreal Exbernal Aside from the pacer clock used internally by your data acquisition board see Chapter 4 some boards provide user clocks or counter timers for external use Counter timers can be used in many configurations Counters can be used singly or in combination with other counters They can also be used with external or internal frequency clock sources and gates The following diagram illustrates the components of a single counter timer dock source countentimer 0 o
197. resets the context of a UserObject before it operates each time See also Context and PreRun Aliasing In data acquisition an error condition arising when a signal is sampled at too slow a rate resulting in a misrepresentation of the analog signal Array A data shape that contains a systematic arrangement of data items in one or more dimensions The data items are accessed via indexes See also Data Shape Analog to Digital Conversion The process of sampling an analog signal and converting it to digital values Asynchronous In an asynchronous operation a device operates without a common signal to synchronize events Rather the events occur at unspecified times VEE control pins are asynchronous Auto Execute An option on the object menus of the data constant objects When Auto Execute is set the object operates when its value is edited Base Frequency See Frequency Source Bitmap A bit pattern or picture In VEE you can display a bitmap on an icon Buffer An area in memory where information is stored temporarily 279 Glossary 280 Button 1 A button on a mouse 2 A graphical object in VEE that simulates a real life pushbutton and appears to pop out from your screen When you press a button in VEE by clicking on it with the mouse an action occurs Cascading Menu A sub menu on a pull down or pop up menu that provides additional selections Channel List A list of the channels used in acquiring a
198. rizes the configuration objects and their purposes Table 8 Summary of the Get and Set Config Object s Name Description Get and Set Sampling Obtain or specify the sampling rate and gain settings for each channel in a given subsystem Get and Set Clocking Obtain or specify the clocking source and external clock frequency for a given subsystem Get and Set Channel Buffer Size Obtain or specify the buffer size of a given channel for a given subsystem Get and Set Range Obtain or specify the programmable voltage range for a given subsystem Get and Set Trigger Obtain or specify the trigger source for a given subsystem Analog Output Table 8 Summary of the Get and Set Config Objects cont Name Description Get and Set Sample Clock Obtain or specify the channel to channel Frequency sample frequency for an internal re trigger and triggered scan of channels Get and Set Channel Filter Obtain or specify the low pass cutoff frequency for a given channel on a given subsystem Get and Set Data Mode Obtain or specify the data I O management configuration for the given channels for a given subsystem Get and Set Multi Channel Mode Obtain or specify the use of multi channel file output aggregate rate and automatic build of the channel gain list Get and Set C T Mode Obtain or specify the mode gate source gate type and pulse type of a C T s
199. rm use a Build Waveform object This object takes a set of values and distributes the values evenly over a span of time It then outputs a waveform To add a Build Waveform object 1 Select Data gt Build Data C gt Waveform and place the Build Waveform object to the right of the Collector object 2 Double click the Build Waveform object to open it 56 Your First Program 3 Connect the data output pin labelled Array from the Collector object to the data input pin labelled Array on the Build Waveform object 4 Select Display C gt Waveform Time and place the object to the right of the Get Single Value object 5 Connect the data output pin from the Build Waveform object to the data input pin on the Waveform Time object 6 Minimize all the objects except the Waveform Time object by clicking the minimize button in the right hand corner of each object You can move objects around to arrange them nicely The program looks something like that shown in Figure 29 For Count Figure 29 Ready to Build a Waveform 57 Chapter 3 58 Note Since we do not know the actual duration over which we are collecting single values the time span in the Build Waveform object is O arbitrary but will do for this example The example program ADSINGLE VFE uses a Timer object to determine the duration and 7 minutes then uses that value as the time span in the Build Waveform object Your prog
200. s Step 2 Connect the Objects Data flows from one object to another through connections For this lesson make a correction to the Waveform Time object so that data flows from the Function Generator object to the Waveform Time object 1 A line is automatically routed between the two pins your program is Click the left mouse button just outside of the data output pin on the Function Generator object When your cursor is near the pin a small square appears around the pin Click the mouse pointer again near the data input pin on the Waveform Time object complete 32 Your First Program Step 3 Run Your Program Once you have placed the objects you need on the work area and connected them you are ready to run the program 1 Click the Run button in the tool bar The program displays a 1000 Hz cosine wave in the Waveform Time object as shown in Figure 12 Function core Frequency tao ampu 1 wot Oo r Prez eg f a TreSan an Mum Pants see Figure 12 The Output from the Simple Program Note From now on when we say to run your program just click the Run button in the tool bar or press C 33 Chapter 3 Step 4 Change Object Parameters You can change the parameters of an object in its open view as follows 1 Inthe Function Generator object click Cosine or the arrow in the Function field A drop down list of selections sho
201. s used as the input signal Click the Run button on the tool bar The output is shown in Figure 50 z Congue hubses d This exaegie deeenecraces che Sieplesr way To aque daca Crai a AD ahr i l Om igura the ASD mobrystem ta malest deviga um defaulica Coc all piber eectings Figure 50 ADSIMPLE VEE after Acquiring Analog Data Try other displays such as Logging AlphaNumeric Strip Chart or Spectrum Freq 93 Chapter 4 Acquiring Data from Multiple Channels Acquiring data from several channels is a simple extension of the last program You need a Get Data Panel object for each channel you select in the A D Configuration dialog box For example Figure 51 shows a program that acquires data on three channels Stairs j d i pa Leda fon Yama 3 3 Traced i Qe Coto Pa r hm 1 4 aly r hemma i Tet i z 4 biaa Conic Habe i Prinia j Oria a M M OS Get Duds Farai e Chami hhubewn E hitre Pami TO Dh i Figure 51 A ProgramTo Acquire Data on Three Channels A one to one correspondence exists between the number of Get Data Panel objects and the number of channels selected in the A D Configuration dialog box For this example the A D Config object was configured for channels 0 1 and 2 as shown in Figure 52 94 Analog Input Figure 52 Configuration for Three Channels Example on Disk The MU
202. s one or more subsystems on it which work independently to acquire or output analog or digital data The following subsystems are provided e Analog input A D e Analog output D A e Digital input DIN e Digital output DOUT and e Counter timer C T DT VPI provides objects that interact with the subsystems on your data acquisition board These objects acquire analyze display or output data For each subsystem there is an object used to configure the subsystem before it begins to operate During configuration your data acquisition board is informed about which channels are going to be used for data acquisition or output and at what sampling rate and gain This information is passed to every other data acquisition object that needs to interact with that subsystem on the data acquisition hardware In the following chapters each subsystem is discussed in detail You will learn how to make external connections configure the subsystem and to connect and use related data acquisition objects Whenever possible the examples on the distribution disks are used and explained In addition the intricacies of using two or more systems simultaneously as well as optimizing your data acquisition program are described xiii About this Manual What Can My Board Do You can write data acquisition programs in VEE with DT VPI using any data acquisition board from DataTranslation This manual describes how to use the data acqu
203. s shown in Figure 49 AD Simpe esas 3 fD Gong 2 Configure hour sai aj lej Auto Srat we T Figure 49 Example on Disk ADSIMPLE VEE As you learned in the last section the A D Config object is required Click the Configure button select the board to use if necessary and specify the channel gain and sampling rate configuration In this example the default configuration of channel 0 at a sampling rate of 1000 Hz is used The Get Data Panel object needs the subsystem handle from the A D Config object You must also indicate which channel you have selected in the A D Configuration dialog box and the number of samples or data points to acquire Enter information directly into the user edit boxes In this example we are using the default settings channel 0 and 1000 samples or points 92 Analog Input Note Make sure that each Get Data Panel object has a corresponding channel configured in the A D Config object Mismatched channels result in a run time error A display object is often used to display the acquired data Because the Get Data Panel object outputs waveform data either a Waveform Time object or an XY Trace object can be used Waveform data has relative time values associated with each data point and thus can be plotted on a Volts vs Time graph Before running this program connect the external device that is supplying an analog signal In this example a 1 Hz sine wave wa
204. s you to indicate which board to use You can access only one board at a time The D A Configuration dialog box enables you to specify which channels you wish to use for data acquisition and the sampling rate and gain for each Change the sampling rate for channel 0 to 2000 Hz Click Add to make the change Click OK to close the dialog box 63 Chapter 3 Note Refer to Selecting an Output Rate starting on page 150 for more information on setting the D A sampling rate to match the frequency time span and number of points in the Function Generator object 6 minutes Your program is ready to run If you have an oscilloscope connected make one last check to be sure it is turned on Step 4 Run Run your program 1 Click Auto Scale on the Waveform Time object to see the output better The output is shown in Figure 33 The waveform is also displayed on the oscilloscope if one is connected at Dih Conrig E Condgas biais p Awvetcars Tiree ig oF A Fui Cat Pangi z bee z Fan Geneon a ou Trost 008 z amter E Papii H Enans y ATDIREK oa o ED re wt au aa il E Fia aF Tracel ii a Tha k3 i S it Tima Som Thre J aj Hu Fiii 1311 3 un Tere Figure 33 Outputting a Generated Waveform 64 Your First Program Step 5 Save Your Program Though this program will not be used in the next lesson you might want to save it for your
205. screw terminal panel connected to the data acquisition board in your system refer to your screw terminal panel documentation e A function generator or other signal source connected to A D channel 0 on the screw terminal panel Make sure the signal source is turned ON 50 Your First Program Step 2 Add the Objects To perform analog input add one object that configures the hardware one object that gathers the data and one object that displays the data 1 Select DT DataAcq gt A D Config and place the A D Config object in the left of the work area Select DT DataAcq gt Data C gt Get Single Value and place this object to the right of the A D Config object The Get Single Value object acquires one sample from the A D subsystem immediately upon executing It does not wait for a pacer clock so a sampling rate is not needed Select Data gt Constant C gt Int 32 and place the Int 32 object to the left of the Get Single Value object This object provides the channel number Select Flow C gt Repeat gt Until Break and place the Until Break object above the Get Single Value object Select Display gt Strip Chart and place this object to the right of the Get Single Value object Connect the objects as shown in Figure 26 51 Chapter 3 52 AD Gomi ae Ba a Trecat ai Figure 26 An Analog Input Program Using Get Single Value Step 3 Configure the A D Subsystem As in the la
206. sequence error Cannot allocate timer data for driver Invalid timer handle Invalid timer mode Invalid timer frequency Invalid timer callback procedure Invalid timer DMA buffer size Illegal synchronous digital I O value requested Cannot allocate simultaneous start list Illegal simultaneous start list handle specified Invalid subsystem handle on simultaneous start list No subsystem handles on simultaneous start list The subsystem has no channel inhibit list The subsystem has no digital I O list The subsystem has not been prestarted Invalid notification procedure Invalid DT Connect transfer count Invalid DT Count transfer size Error Number 111 112 113 114 115 116 117 118 119 200 201 202 203 204 205 206 207 208 209 210 211 Description Cannot allocate channel inhibit list Cannot allocate digital I O list Channel inhibit list has been filled incorrectly DASS handle is already on simultaneous start list Cannot allocate range list No range list No buffers in process Additional required subsystem in use Wrap mode mismatch Cannot allocate a buffer control block for the requested data buffer Cannot allocate the requested data buffer Invalid buffer handle HBUF specified Could not lock specified HBUF Specified HBUF is locked Specified HBUF is already on a different list Reallocation of a buffer control block was unsuccessful Reallocation of the data b
207. ser supplied signal for use as the pacer clock for a data acquisition instead of the onboard oscillator The counter timer is configured to output a generated signal of a certain frequency this signal is then used by the A D subsystem as an external clock To accomplish this the output from the counter timer for example C T OUT1 on the screw terminal panel must be connected to the A D external clock input A D EXT CLK on the screw terminal panel Figure 106 shows an example of using the counter timer as a clock GT Config Start Acq I m 7 E AD Config Get Data Panel LA T Y Trace Note Fad on screw terminal panel C T G UTL is connected to AD BST CLE Figure 106 Using a Signal Generated by the C T as the External Clock to the A D Subsystem Note When it executes C T Config object initializes the counter timers on any Data Translation data acquisition board The initialization causes a spike on the output of the counter timer Therefore if you are using the counter timer as an external clock or external trigger ensure that the Start Acq object is executed for the counter timer subsystem before starting the A D subsystem 209 Chapter 8 210 Configuring the C T as a Clock To use the counter timer circuit as a clock select DT DataAcq gt C T Config and click Configure Set the mode to Generate Rate If you are using the internal clock as the source select Internal under Clock S
208. st Mode You probably noticed that the program to acquire data in burst mode uses the same objects we have already worked with The difference lies in the configuration To set up burst mode you need to use the A D Advanced Configuration dialog box On the A D Config object click Configure Because you intend to acquire a burst of data click Advanced The A D Configuration dialog box enlarges to show advanced features one of which is burst mode Using the A D Advanced Configuration dialog box you can set up the channel list just as you would normally For our example we intend to use channels 0 1 and 2 As you add each channel click the checkbox labeled Enable in the Burst Duration section and click the radio button next to Samples Set the channels to the following rates and gains Channel Rate Hz Gain Burst Burst Duration Enabled samples 0 10000 1 yes 1024 1 10000 1 yes 1024 2 10000 1 yes 1024 Figure 58 shows how the dialog box should look when you are done 105 Chapter 4 106 Configuration DT3010 7 Analog Input 0 p Hifo a frome 10 00 Figure 58 Configuring the A D Subsystem To Acquire Data in Burst Mode Note In general it is more precise to specify burst duration in terms of number of samples instead of number of seconds In this way you know exactly how many samples to expect Analog Input Using an External Trigger To make things a little more interesting we will a
209. st lesson we will be using the A D subsystem which performs the analog data acquisition from the external signal source converting it to digital form for use by VEE Before you can run the program you need to configure the A D subsystem on the data acquisition board however in this lesson the A D Config object is used only to configure a subsystem handle the channel list sampling rate and gain have no meaning when using Get Single Value 1 Click the Configure button on the A D Config object The A D Configuration dialog box appears Your First Program Note If you have more than one data acquisition board installed or more than one instance of that board a dialog box asks you to indicate which board to use You can access only one board at a time Since the sampling rate gain and channel list are meaningless when using Get Single Value just click OK to close the dialog box and to configure the A D subsystem Note The Get Single Value object uses the hsubsys from the A D Config object but does not use the channel list The Integer Constant object passes the channel number and the appropriate gain is automatically used to acquire the signal Your program is ready to run Make one last check to be sure your equipment is connected correctly and turned on Step 4 Run To run your program perform these steps 1 Set the external function generator to output a waveform a square wave will work ni
210. subsystem to sample data at a rate of 1000 Hz Therefore according to the Nyquist theorem the high est frequency component of the input signal must be less than half of 1000 Hz to avoid aliasing Since the input signal is well under 500 Hz we do not have a risk of aliasing Run the program by clicking the Run button Click Auto Scale on the Waveform Time object to see the output better The output is shown in Figure 24 47 Chapter 3 48 ajre Figure 24 512 Samples of Acquired Data Step 5 Acquire Continuously You can repeat the analog input continuously until you press the Stop button To do this we will add an Until Break object 1 2 Select Flow C gt Repeat C gt Until Break and place the Until Break object above the Get Data Panel object Connect the A D Config object s sequence output pin to the Until Break object s sequence input pin This connection ensures that the A D subsystem is configured before the acquisition loop begins Connect the Until Break object s data output pin to the Get Data Panel object s sequence input pin as shown in Figure 25 Your First Program Figure 25 Acquiring Data Continuously 4 Run the program The Waveform Time object displays 512 points of the acquired signal at a time 5 When you are ready to stop the program click the Stop button Acquisition actually continues for a moment or two until the memory buffers on the hardware
211. tes specifying the channel in the channel gain list gain Intl6 2 bytes specifying the gain applied to the previous channel 271 Appendix C 272 Product Support General Checklist 0 000000 ccc cece cee ee eee ees 274 Service and Support tanime cece eee 275 GlOSSaty iis s8 Gates god ee eace toe eee ee gee 279 273 Appendix D 274 General Checklist Should you experience problems using DT VPI please follow these steps 1 Read all the appropriate sections of this manual Make sure that you have added any Read This First information to your manual and that have used this information Check your distribution disk for a README file If present this disk will include the latest installation and configuration information Check that you have installed and configured your board properly See the instructions in Chapter 1 Installing DT VPI in this manual Check that you have installed your hardware properly See the installation documentation for your board Check that you have installed any other software properly See the installation documentation for the associated software Search the DT Knowledgebase in the Support section of the Data Translation web site at www datatranslation com for an answer to your problem If you are still having problems please follow the instructions provided in the next section Service and Support Service and Support If you h
212. the dtv GetFileSize advanced function The file it creates MUTLCHAN DTV can be read by the MUTLFILE VEE program Configuring for Slow Sampling Rates By default the Disable Auto CGL option in the A D Advanced Configuration dialog box is unchecked enabled DT VPI automatically builds the channel gain list so that the specified channels and their specified rates can be achieved To achieve the sampling rate closest to that specified for each channel data may actually be collected for unspecified channels but never used However the automatic channel gain list is somewhat inefficient when using low sampling rates less than 1 kHz Therefore you may want to avoid having DT VPI automatically build the channel gain list To do so place an X in the checkbox next to Disable Auto CGL This disables the automatic build of the Channel Gain List and causes data to be sampled only from the specified channels Individual channel sampling rates are ignored instead the aggregate rate is set and the channel rates are equal aggregate rate divided by the number of channels Analog Input Sending Data Through DDE Dynamic Data Exchange or DDE defines a message based protocol for communication between Windows applications The communication takes place between a DDE client and DDE server The DDE client requests a conversation with the DDE server about a certain topic The client can then request information or services from the server send
213. the Objects 0 cece eee eee 67 Step 3 Configure the Digital Input Port 68 Step 4s Runt aii dicen bees aad sani nein eke 69 Step 5 Save Your Program 66 cece ee eee 69 Lesson 7 Change the Configuration Programmatically 70 Step 1 Gather the Equipment 00000 70 Step 2 Modify the Program 00 00 0000 00s 71 Step 3 Add the Configuration Objects 72 Step 4 Add User Input 00 0 cece eee eee 74 Steps RUD iaceinctasededcas a wale ee whale Ed eds 76 Step 6 Save Your Program 66 6 eee eee eee 77 Contents vi What s Next iuc acti nd gente nd eR eed hea Me add awe es 78 Chapter 4 Analog Input 0 0 02 eee eee eee 79 Connecting External Sensors 0 000 e eee eens 81 Configuring for Analog Input 0 00000 81 Selecting a Board when More than One Data Acquisition Board Is Installed 0000 c cece eee ees 82 Building a Channel List 0 00000 eee eee 83 Selecting a Sampling Rate 0 0 00 e eee 84 Filtering an Analog Input Signal 85 Selecting the Gain 0 eee eee 86 Selecting an Input Range and Type 5 87 Selecting a Clock and Trigger Source 205 88 Specifying a Subsystem Handle 0 89 Starting an Analog Input Acquisition 5 91 Acquiring Data from a Single Channel
214. the header size in bytes 2 bytes specifying the version of the file header 40 bytes specifying the board name as defined by the user when the driver was installed The board name is a null terminated ASCII string 40 bytes specifying the subsystem name The subsystem name is a null terminated ASCII string 2 bytes specifying the size of each data sample in bytes 2 bytes specifying the resolution of the board in bits typically 12 or 16 2 bytes specifying the encoding of the data A value of 0 is binary encoding and a value of 1 is twos complement encoding 8 bytes specifying the minimum voltage of the voltage range This value is the minimum voltage of the device s range divided by the gain 8 bytes specifying the maximum voltage of the voltage range This value is the maximum voltage for the device s range divided by gain 2 bytes specifying the channel number 8 bytes specifying the rate 8 bytes specifying the time and date the file was created The value is the number of seconds since 00 00 hours 1 January 0001 AD given in UTC Multi Channel Format This section contains reference information about the file header used by the A D Config object for multi channel files The header is a minimum of 128 bytes long and additionally includes the channel gain list entries and data headersize Int16 version Intl6 boardname Char 40 subsysname Char 40 datawidth Int16 resolution Int16 encoding Int16
215. thread and Thread Main Menu The menus located in the VEE menu bar The main menus may be opened by clicking or dragging on the menu titles in the menu bar Mapping To associate a set of independent values with an array when the array is a function of the values Maximize To enlarge a window to its maximum size In VEE the UserObject has a maximize button Glossary Menu A collection of features that are presented in a list See also Cascading Menu Main Menu Object Menu Pop Up Menu and Pull Down Menu Menu Bar A rectangular bar at the top of the VEE window that contains titles of the pull down main menus from which you select features Menu Title The name of a menu within the VEE menu bar For example File or Edit Minimize 1 To reduce an open view of an object to its smallest size an icon 2 To reduce a window to its smallest size an icon Mouse A pointing device that you move across a surface to move a pointer within the VEE window Mouse Button One of the buttons on a mouse that you can click double click or drag to perform a particular action with the corresponding pointer in the VEE window Network A group of computers and peripherals linked together to allow the sharing of data and work loads Object A graphical representation of an element in a program such as an instrument control display or mathematical operator An object is placed in the work area and connected to other objects to
216. ting 36 screw terminal panel 3 218 securing a program 226 selecting a board 148 analog input 82 sequence input pin 22 Index sequence output pin 22 SERIALIO VEE example program 248 service 275 Set C T Frequency object 118 171 Set C T Measure Duration object 118 171 Set C T Mode object 118 171 Set C T Pulse Width object 118 171 Set Channel Buffer Size object 117 170 Set Channel Filter object 118 171 Set Clocking object 117 170 Set Config objects 117 170 Set Data Mode object 118 171 Set Multi Channel Mode object 118 171 Set Range object 117 170 Set Sample Clock Frequency object 171 Set Sampling Clock Frequency object 118 Set Sampling object 72 117 119 170 173 199 Set Trigger object 107 117 170 214 sharing DMA resources 201 Show Data Flow button 25 Show Execution Flow button 26 Show Terminals option 22 Simple Driver 26 SIMULTAN VEE example program 198 248 single value 101 164 Single Value transfer 195 single ended channels 87 154 sizing an object 19 SLOWAD VFE example program 248 Spectrum Freq object 93 Start Acq object 91 155 174 Start object 27 starting analog input operations 91 analog output operations 155 two subsystems simultaneously 200 VEE 8 states of channels 100 162 Step button 226 Stop Acq object 119 122 131 162 173 using with Get Config object 172 Stop button 48 54 69 97 Strip Chart object 51 53 93 subsystem A D 45 changing configur
217. tomatically when the Put Data Panel or Put Data Function receives the data include a Start Acq object after the Put Data Panel or Put Data Function object Be sure to deselect the Automatic Start option in the D A Advanced Configuration dialog box Note If Automatic Start is selected in the D A Configuration dialog box executing a Start Acq object after a Put Data Panel or Put Data Function object raises error 2010 155 Chapter 5 Outputting Analog Data from a Single Channel The simplest analog data output program outputs a specified number of samples from a single channel Figure 82 shows what the DASIMPLE VEE example program in the Examples Dataacq directory looks like cl DA cong Conngune habra Ih a E EZE p Pur Data Pane el ee Function Generator Ce E T AL Scata Time Figure 82 Example on Disk DASIMPLE VEE As you learned in the last section the D A Config object is required Click the Configure button select the board to use if necessary and specify the channel gain and sampling rate configuration In this example the default configuration of channel 0 at a sampling rate of 1000 Hz is used Take a moment to consider the connection from the D A Config object to the Put Data Panel object The Put Data Panel object is always to the right of the D A Config object because it needs the subsystem handle from the D A Config object 156 Analog Output In the
218. ubsystem Get and Set C T Frequency Obtain or specify the frequency and duty cycle of a C T subsystem Get and Set C T Pulse Width Obtain or specify the delay and pulse width of a C T subsystem Get and Set C T Measure Duration Obtain or specify the duration over which to measure events Note For more information on the get and set config objects refer to the DT VPI online help Often the get and set config objects are used as a pair Place the get config object so that it executes before the set config object Then connect the outputs from the get config object to the inputs of the set config object except for the one or two parameters you intend to change 171 Chapter 5 172 CAUTION Because the set config objects change the configuration of the subsystem it is important that you not reconfigure a running subsystem To avoid this situation place a Stop Acq object before the get config object For example the program shown in Figure 90 uses the Get Sampling and Set Sampling objects to change the analog output rate the sampling rate The D A Config object is configured to output a 1000 Hz on channel 0 DACO Automatic Start is selected as usual We have retitled the Allocate Real 32 Array Object to Real Array w New Rate D miany 4 Dia Config p Put Date Farw i Siop Acg Funchon Generator Funcion Cosine Frequency Fy Amplitude 10 i oe Dex
219. uence input pin Get Data Panel E Channel l l hEubsys k Data input pin T Data output pins N mus Points l Data Sequence output pin Figure 10 The Various Pins on an Object Some objects have all four kinds of pins while others have only one or two kinds of pins In an object s open view the data input and output pins can be represented as input and output terminals which display their terminal labels The terminal labels are visible only in the open view and only if the Show Terminals option is active Connecting Objects Data flows from one object to another through connections from left to right A data flow connection is made between the data output pin of the first object and the data input pin on the second object To connect two objects first place the objects on the work area 1 Click the left mouse button just outside of the data output pin of the first object Do not click on the pin itself or inside the object When it is in the right position the cursor turns into a small square 2 Position the mouse pointer near the data input pin on the other object When it is near an available data input pin a small square appears around the input pin 3 Click A line is automatically routed between the two pins the connection is complete Adding Data Input Terminals to an Object You can add an input terminal to an unlocked object if you need one by performing one of thes
220. uffer The subsystem is in Ready state e The Function Generator object generates 1000 points of data and passes the data to the Put Data Panel object The Function Generator object generates data once only e When the Put Data Panel object executes Automatic Start is checked in the D A Configuration dialog box the subsystem is in the Running state The data for each channel in this case one channel is stored in its own data queue DT VPI sets aside enough memory for each data queue to hold four seconds of data depending on the channel s sampling rate e Oneach iteration of the Until Break object the data is pulled out of the data queue mixed together if another channel were configured and stored in the Mixed Data Buffer If one channel has less data than is allowed by the critical threshold then depending on the data mode for that channel that channel goes to the Done state in Gap Free data mode or to Waiting state in Allow Gaps data mode The goal is to keep the Mixed Data Buffer as full as possible If however VEE is executing an object that takes awhile to complete the Mixed Data Buffer might empty If this happens data acquisition stops on all channels You can remedy this situation by priming the Put Data Panel object with more data e When the thread finishes executing the program stops but data acquisition continues until the Mixed Data Buffer is emptied then data output stops If you pause or stop th
221. uffer was unsuccessful Invalid sample size specified Cannot allocate buffer transfer list Invalid list handle specified Cannot free list because buffer s name has not yet been removed 265 Appendix B 266 Error Number 212 213 214 215 216 217 218 219 Description Specified HBUF is not locked Invalid DMA channel specified DMA channel is already in use by another subsystem Invalid interrupt level requested The requested interrupt level is already in use by another DT Open Layers subsystem There are no samples in the specified buffer There are too many samples specified for the buffer Buffer is too small for requested copy operation A File Formats Single Channel Format 0 000 cece eee eee eee ee 268 Multi Channel Format 00 0 0 cece cece ee eee 269 Channel Gain List Entries 0 000 000 ccc eee ee eee 271 267 Appendix C 268 Single Channel Format This section contains reference information about the file header used by the A D Config and D A Config objects for disk I O The format discussed is VEE binary format As listed in the following table the header is 124 bytes long and is followed by the data headersize Int16 version Intl6 boardname Char 40 subsysname Char 40 datawidth Int16 resolution Int16 encoding Int16 minvolts Real64 maxvolts Real64 channel Int16 frequency Real64 timedate Real64 2 bytes specifying
222. uired configuration If multiple subsystems are installed one must be selected to execute a subsystem configuration object The Channel Number entered is invalid for the current operation Either the channel is not on the current channel list or it is a channel that is not supported by the subsystem More data points than can be accepted by the current Channel Buffer Size have been put to this channel A Put Data Panel or Put Data Function object tried to write too many data points toa D A subsystem channel that has not been started Too many data points were requested from a subsystem A Get Data Panel or Get Data Function object was executed with a C T subsystem hSubsys and the number of points specified was greater than one Input must be Int32 Input must be Real Input must be Text Input must be Enum Input arrays must be of the same size and shape 2029 2030 2031 2032 2033 2034 2035 2036 2037 2038 2039 The saved device configuration is invalid Please reconfigure the device The program was saved with a configuration that included a board name and subsystem type that does not match the present configuration Can not find any supported hardware No DT Open Layers Windows driver and board was found in the system Analog output device required for threshold triggering in use Please close the analog output device on this board The analog threshold trigger requires the D A subsystem to be
223. ure your equipment is correctly connected and turned on Step 5 Run Run your program 1 When acquisition stops change the setting on the Real Slider object by dragging the knob up or down Note the effect in the Waveform Time object each time you run Figure 40 shows the output with the sampling rate set to 3961 Hz Your First Program Figure 40 Changing the Sampling Rate with a Real Slider Step 6 Save Your Program If you want to save the changes you just made to the original AD VEE program click the Save button E Otherwise select Save As from the File menu and provide a different file name such as AD2 77 Chapter 3 78 What s Next Now that you have finished this introduction to DT VPI s data acquisition capabilities try some things on your own Use the following documents in addition to this one to help you VEE Multimedia tutorials VEE on line help VEE Pro User s Guide VEE Pro Advanced Techniques VEE OneLab User s Guide VEE OneLab Advanced Techniques and DT VPI on line help B Analog Input Connecting External Sensors 0 000 e eee eee eee 81 Configuring for Analog Input 0 0 0 c eee eee 81 Starting an Analog Input Acquisition 4 91 Acquiring Data from a Single Channel 92 Acquiring Data from Multiple Channels 94 Acquiring Analog Data Continuously 004 96 Acquiri
224. ut Pin A connection point on the right side of an object that propagates data flow to the next object and passes the results of the first object s operation on to the next object DataSet A collection of Record containers saved into a file for later retrieval The To DataSet object collects Record data on its input and writes that data to a named file the DataSet The From DataSet object retrieves Record data from the named file the DataSet and outputs that data as Record containers on its Rec output pin See also Record Data Shape A pre defined structure that defines how data is grouped together for example an array Data Type A pre defined structure that determines how data is organized and treated by VEE for example Real or Complex DDE Client An application that requests a DDE conversation with another application VEE has only client capabilities See also DDE Dynamic Data Exchange DDE Dynamic Data Exchange A communication mechanism that allows VEE to communicate with other Windows applications that support DDE VEE can send data to and receive data from such applications Also VEE can execute commands in the other application Examples of Windows applications that support DDE are Microsoft Excel and Microsoft Word for Windows DDE Server An application that responds to a request for a DDE conversation from another application VEE does not have DDE server capabilities See also DDE Dynamic Data Exchange
225. utput Solhware termal gate trigger Figure 101 Components of a Single Counter Timer This chapter discusses how to control the counters timers on your data acquisition hardware This chapter includes many example programs and explanations of using the data acquisition objects provided by DT VPI You will learn how to create programs to e Use the counter timer as a clock e Use the counter timer as a trigger e Provide an external trigger to the counter timer e Use the counter timer to count events and e Use the counter timer to measure frequency Using Counters and Timers Terminology Before you configure the counter timer you need to understand the terminology used when dealing with counter timers In DT VPI counter timers can be set to one of four modes e Generate Rate mode to use the counter timer as a clock e One shot mode to use the counter timer as a trigger e Count Events mode to use the counter timer as a counter e Measure Frequency mode to use the counter timer to measure the frequency of occurrence of an event Pulse Type If the pulse type is High to Low the low portion of the total clock period is the active portion of the counter timer output If the pulse type is Low to High the high portion of the total clock period is the active portion of the counter timer output Duty Cycle The duty cycle indicates the percentage of the total clock period that is active By default the total c
226. ve percent 25 off the then current list prices for such releases 3 EXCLUSIONS Support Services do not include a the provision of or support for Products other than those identified in the Agreement as to which the applicable license and support fees shall have been paid including without limitation compilers debuggers linkers or other third party software or hardware tools or components used in conjunction with any Product b services required as a result of neglect misuse accident relocation or improper operation of any Product or component thereof or the failure to maintain proper operating and environmental conditions c support for processors other than Licensed Processors or for Products modified by or on behalf of Licensee d repair or restoration of any Software arising from or caused by any casualty act of God riot war failure or interruption of any electrical power air conditioning telephone or communication line or any other like cause Data Translation Support Policy It is Licensee s responsibility to have adequate knowledge and proficiency with the use of the compilers and various software languages and operating systems used with the Products and this Support Policy does not cover training of or detailed direction on the correct use of these compilers operating systems or components thereof On site assistance shall not be provided hereunder but may be available on a per call basis at Data Tra
227. vel dtv SetTriggerThreshold dtv SetTriggerThreshold sets the trigger threshold level in DACO When the analog input signal passes the threshold level the subsystem begins to report the data samples Boards such as the DT2839 and DT3010 Series that support threshold triggering can use this function Typically the input to hSubsys is the subsystem handle for the A D subsystem Table 27 dtv SetTriggerThreshold Terminal Input or Type Description Output hSubsys input Int32 subsystem handle Ret Value output Int32 subsystem handle Threshold input Int32 trigger threshold level 239 Chapter 10 Accessing the Unsecured Data Acquisition UserObjects If you need to tinker with the inner workings of the subsystem configuration objects or the get and put data objects you have access to the unsecured versions of those UserObjects Select File gt Merge or File gt Open and select one of the following files from the WEE Pro 6 0 DataAcq or VEE OneLab 6 0 DataAcq directory Table 28 Files Containing the Unsecured Versions of the UserObjects Filename Description adconfig vee A D Config object ctconfig vee C T Config object daconfig vee D A Config object diconfig vee Digital In Config object doconfig vee Digital Out Config object getdataf vee Get Data Function object getdatap vee Get Data Panel object getptdat
228. ware The term click a menu selection icon button or object means to move the mouse pointer to the appropriate location and quickly press and release the left mouse button The term double click means to click the left mouse button twice in rapid succession The typographical conventions are listed in the table below Table 1 Convention s Example of Convention Description DT VPI User s Manual Italic is used for book titles and new terms Get Data Panel object Helvetica font is used for names of objects DT DataAcq menu Bold is used for menu names text in dialog boxes or any text you see on the screen About this Manual Table 1 Conventions cont Example of Convention Description File gt Open The arrow C gt is used in a shorthand notation to show the location of VEE features in the menus For example File C gt Open means to select the File menu and then select Open Represents a key on the PC keyboard that you should press Press Represents a combination of keys on the PC keyboard that you should press at the same time Related Documents The following documents may help you to use DT VPI with VEE e DT VPIonline help e VEE Multimedia tutorials e VEE online help e VEE Pro User s Guide e VEE Pro Advanced Techniques e VEE OneLab User s Guide and e VEE OneLab Advanced Techniques xix About this Manual Where to G
229. wn in Figure 13 appears Aula y Time Figure 13 Changing Cosine to Sine 2 Click Sine to select the sine function 3 Edit the Frequency field to read 100 instead of 1000 as shown in Figure 14 34 Your First Program oom f fc Prase Deg fo Time Span iin Mm Pata o Figure 14 Changing the Frequency from 1000 Hz to 100 Hz Run the program The displayed waveform is now a 100 Hz sine wave as shown in Figure 15 Figure 15 The Output from the Program 35 Chapter 3 Try changing a few object parameters on your own e Click Deg or the arrow in the Function Generator object and change the phase units to Rad Now click the Phase value field and enter the value PI Click the Run button _ and note the phase shift in the displayed waveform Now change the Phase value back to 0 and the units back to Deg e The y axis limits of the Waveform Time object are preset to 1 through 1 Click each value field and change the limits to 2 through 2 you will see the waveform displayed within the new limits Now click Auto Scale the waveform is automatically scaled from 1 to 1 Step 5 Print the Screen To print the screen click the Print button on the tool bar VEE prints the VEE window on the printer indicated in the Print setup dialog box Step 6 Save Your Program You can save your program whatever is in the work area whether a complete program or not at any time by perf
230. xis of time If you are outputting data that you originally acquired use the same sampling rate for both analog input and output Analog Output If you are outputting data generated internally in VEE such as with the Function Generator object then the process is a little more complicated For example suppose you want to output 10 cycles of a cosine waveform on the DAC Set up the Function Generator object s settings to generate a cosine wave with a Frequency of 1000 Hz and a Time Span of 10 ms A frequency of 1000 Hz 1000 samples per second means that each cycle is 1 ms long If you set the Function Generator object s Time Span for 10 ms then data for 10 cycles is generated You could also set the Function Generator object s Frequency for 2000 Hz and its Time Span for 20 ms and still get 10 cycles The number of points generated by the Function Generator object is related to the Rate you set for the DAC in the D A Config object s configuration dialog box The Rate setting is actually the sampling frequency which is the frequency at which the generated data points are output that is a high sampling frequency means they are close together in time and a low sampling frequency means that data points are output far apart in time You can adjust the D A Rate and the Function Generator object s NumPoints setting to achieve the right duration for the output waveform and the right frequency of the output waveform

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