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NI-DAQ User Manual for PC Compatibles, Version 6.9

1. Empty Buffer Untransferred Data Transferred Data Figure 4 1 Double Buffered Input with Sequential Data Transfers The double buffered input operation begins when the DAQ device starts writing data into the first half of the circular buffer Figure 4 1a After the device begins writing to the second half of the circular buffer NI DAQ can copy the data from the first half into the transfer buffer Figure 4 1b You can then store the data in the transfer block to disk or process it according to your application needs After the input device has filled the second half of the circular buffer the device returns to the first half of the buffer and overwrites the old data NI DAQ can now copy the second half of the circular buffer to the transfer buffer Figure 4 1c The data in the transfer buffer is again available for use by your application The process can be repeated endlessly to produce a continuous stream of data to your application Notice that Figure 4 1d is equivalent to the step in Figure 4 1b and is the start of a two step cycle National Instruments Corporation 4 3 NI DAQ User Manual for PC Compatibles Chapter 4 NI DAQ Double Buffering Potential Setbacks The double buffered coordination scheme is not flawless An application might experience two possible problems with double buffered input The first is the possibility of the DAQ device overwriting data before NI DAQ has copied it to the
2. NI DAQ User Manual for PC Compatibles xiv ni com Table 1 MIO and Al Device Classifications Continued About This Manual Number of SE Device Channels Bit Type Functionality PXI 6023E 16 12 bit PXI Al PXI 6024E 16 12 bit PXI MIO PXI 6025E 16 12 bit PXI MIO PXI 6030E 16 16 bit PXI MIO PXI 6031E 64 16 bit PXI MIO PXI 6034E 16 16 bit PXI Al PXI 6035E 16 16 bit AI 12 bit AO PXI MIO PXI 6040E 16 12 bit PXI MIO PXI 6052E 16 16 bit PXI MIO PXI 6053E 64 16 bit PXI MIO PXI 6070E 16 12 bit PXI MIO PXI 6115 4 DIFF only 12 bit PXI MIO PXI 6120 4 DIFF only 16 bit PXI MIO VXI MIO 64E 1 64 12 bit VXI MIO VXI MIO 64XE 10 64 16 bit VXI MIO National Instruments Corporation XV NI DAQ User Manual for PC Compatibles Introduction to NI DAQ This chapter describes how to set up your DAQ system and configure your DAQ devices About the NI DAQ Software for PC Compatibles Thank you for buying a National Instruments DAQ device which includes NI DAQ software for PC compatibles NI DAQ is a set of functions that control all of the National Instruments plug in DAQ devices for analog I O digital I O timing I O SCXI signal conditioning and RTSI multiboard synchronization NI DAQ has both high level DAQ I O functions for maximum ease of use and low level DAQ I O functions for maximum flexibility and performance Examples of high level functions are
3. National Instruments Corporation 3 25 NI DAQ User Manual for PC Compatibles Chapter 3 Software Overview When using SCXI analog input modules use the SCXI functions to set up the SCXI chassis and modules before using the AI DAQ SCAN and Lab_ISCAN functions shown in the following flowcharts Building Block 1 Configuration Five configuration functions are available for creating the first building block as shown in Figure 3 4 However you do not have to call all five functions every time you start a data acquisition Alter low level board configuration such as analog input mode AI_Configure Add AMUX 64T Y Configuration AI_Mux_Config Alter start trigger external conversion Y and external scan clock modes DAQ Config Y Alter pretrigger mode DAQ StopTrigger Config y Alter double buffered mode DAQ DB Config Figure 3 4 Buffered Data Acquisition Application Building Block 1 Configuration NI DAQ records the device configurations and the default configurations See the Init_DA Brds description in the NI DAQ Function Reference Online Help file for device default configurations Therefore if you are satisfied with the default or the current configurations of your devices your configuration building block will be empty and you can go on to the next building block Start NI DAQ User Manual for PC Compatibles 3 26 ni com Chapter 3 Software Overview Building B
4. s sssssssssseesessseessestsresrerrsresreseeresreresresesreses 3 16 Single Channel Analog Input Functions 00 0 eee ee eeeeeeeeeeereereees 3 16 Data Acquisition FUNCTIONS eee eect eeeeseceeeeseceeecaeeeeeeaeceeeaeenseeateneenaes 3 20 High Level Data Acquisition Functions cece eeeeeseeeeereeeeees 3 20 Low Level Data Acquisition Functions 0 0 cece cece eeeeeeeeeeeeeees 3 21 Low Level Double Buffered Data Acquisition Functions 3 23 Data Acquisition Application Tips cece ee ceeeeeeseeeseceeeeeeeeeeees 3 24 Mulltirate Scanmins 225 i iisite dik EEE RE EAEAN eaten 3 32 Analog Output Function Group ceceeeescecesecseeesesseceseeeeesecsecseeeaeesseeaeseeecaesseeeaeeeees 3 35 One Shot Analog Output FunctionS essssesesssseesersresrsresresesresrerestsseseesreresee 3 35 Analog Output Application Tips eee eee eeeeeeeeeeeeeseeneeeeeeees 3 36 Waveform Generation Functions 0 cece eeceeseeeeeseceseeeeeseeaeeneeeaeseeeeaeenees 3 39 High Level Waveform Generation Functions 000 0 eee eeeeeeeees 3 39 Low Level Waveform Generation Functions eee eeeeeeeeees 3 39 Waveform Generation Application Tips 0 0 eee eeeeereeeeeeeees 3 41 Digital 1 0 Function Group seinar aer eni a Mea evee AE EE SE 3 52 DIO 24 6025E AT MIO 16DE 10 DIO 96 and Lab and 1200 Device Groups eee eeesseeeseceseeseeeeeeseeneeesseseeeaeenees 3 55 DIO 32F and 653X Device Groups ce eececeesseeeeseceeeeseesse
5. Configure the desired module y fora single channel operation SCXI_Track_Hold_ Setup Latch the analog inputs by y putting the module into Hold mode SCXI_Track_Hold_Control Acquire data from the desired channel on the module using the AT functions Single Analog Input Do you wish to take more data while the module is in Hold mode Maintain Hold mode Yes Put the module back into Track mode to sense the new input values SCXI_Track_Hold_Control Have you acquired all the data you need from this module Yes Disable the Track Hold setup of the module to free the counter resource on the data acquisition device SCXI_Track_Hold_Setup Figure 3 45 Single Channel or Software Scanning Operation Using an SSH Module in Parallel Mode The initial SCXI_Track_Hold_Setup call signals the driver that the module is used in a single channel application and puts the module into track mode The first SCXI_Track_Hold_Control call latches or samples all the module inputs subsequent AT calls read the sampled voltages It is important to realize that all AI operations that occur between the first SCXI_Track_Hold_Control call which puts the module into NI DAQ User Manual for PC Compatibles 3 122 ni com Chapter 3 Software Overview hold mode and the second control call which puts the module into track mode acquire data that was sampled at the time of the first
6. If any of the modules to be scanned are SSH modules you must establish the Track Hold setup of each one To synchronize multiple SSH modules you can configure the module that is receiving the Track Hold control signal to send the Track Hold signal on the SCXIbus so that any other SSH module can use it The Track Hold signal can be from either the DAQ device counter or an external source The SCXI_SCAN Setup call establishes the module scan list which NI DAQ downloads to Slot 0 Each module is programmed for automatic scanning starting at its given start channel If you need the SCXIbus during the scan to route the outputs of multiple modules this function resolves any contention If you are using an SCXI 1200 you can include the SCXI 1200 in the module scan list In many of the data acquisition function descriptions in the NI DAQ Function Reference Online Help file the count parameter descriptions specify that count must be an integer multiple of the total number of channels scanned In channel scanning acquisitions in multiplexed mode the total number of channels scanned is the sum of all the elements in the numChans array in the SCXI_SCAN_ Setup function call If any of the modules in the module scan list are SCXI 1100 SCXI 1102 B C VXI SC 1102 B C SCXI 1122 SCXI 1125 SCXI 1126 SCXI 1141 SCXI 1142 SCXI 1143 SCXI 1520 SCXI 1530 SCXI 1531 or SCXI 1540 modules you can use SCXI_Set_Gain to change the gain or range setting on e
7. CTR_Simul_Op CTR_Square National Instruments Corporation 3 77 Specifies the counting configuration to use for a counter Configures the specified counter for an event counting operation and starts the counter Reads the current counter total without disturbing the counting process and returns the count and overflow conditions Disables or enables and sets the frequency of the 4 bit programmable frequency output Configures the specified counter for period or pulse width measurement Causes the specified counter to generate a specified pulse programmable delay and pulse width Converts frequency and duty cycle values of a square wave you want into the timebase and period parameters needed for input to the CTR_Square function that produces the square wave Turns off the specified counter operation and places the counter output drivers in the selected output state Restarts the specified counter operation Configures and simultaneously starts and stops multiple counters Causes the specified counter to generate a continuous square wave output of specified duty cycle and frequency NI DAQ User Manual for PC Compatibles Chapter 3 Software Overview CTR State Returns the OUT logic level of the specified counter CTR_Stop Suspends operation of the specified counter so that NI DAQ can restart the counter operation Counter Timer Operation for the CTR Functions Figure 3 26 shows the 16 bit counters avai
8. Create files of type frm form definition and event handling code bas Visual Basic generic code module or cls Visual Basic class module and add them to the project Include the NI DAQ include file for Visual Basic nidaq32 bas into your project You may also want to include nidaqens inc and nidagerr inc The NI DAQ include files for Visual Basic are located in the Include directory under your NI DAQ directory For Visual Basic 5 0 6 0 you can select the Project Add Module menu option click on the Existing tab then select the module of your choice Alternatively you can add a reference to the National Instruments Data Acquisition Type Library which is part of the NI DAQ DLL In Visual Basic 5 0 6 0 select the Project References menu option and check National Instruments Data Acquisition Library If you do not see it listed there click on the Browse button and locate nidag32 d11 in your Windows system or Windows system32 directory Run your application by clicking the Run button 3 Note In Visual Basic function declarations have scope globally throughout the project In other words you can define your prototypes in any module The functions will be recognized even in other modules For information on using the NI DAQ Visual Basic Custom Controls see the NI DAQ Events in Visual Basic for Windows section in Chapter 3 Software Overview Please also refer to the Programming Language Considerations topic in the N
9. The second potential problem occurs when an input device overwrites data that NI DAQ is simultaneously copying to the transfer buffer NI DAQ returns an overwrite error overWriteError when this occurs The situation is presented in Figure 4 3 Incoming Device Data Y Circular Buffer T 4 afi a hv i b 7 kev VA i a e ma K Transfer Buffer p a as gt _ 7Y RAW P ST Overwrite Error Empty Untransferred Transferred Corrupted Buffer Data Data Data Figure 4 3 Double Buffered Input with an Overwrite In Figure 4 3b NI DAQ has started to copy data from the first half of the circular buffer into the transfer buffer However NI DAQ is unable to copy the entire half before the DAQ device begins overwriting data in the first half buffer Figure 4 3c Consequently data copied into the transfer buffer might be corrupted that is it might contain both old and new data points Future transfers will execute normally as long as neither of the problem conditions re occur National Instruments Corporation 4 5 NI DAQ User Manual for PC Compatibles Chapter 4 NI DAQ Double Buffering Double Buffered Output Operations Double buffered output operations are similar to input operations The circular buffer is again logically divided into two halves By dividing the buffer into two halves NI DAQ can coordinate user access to the data buffer with the DAQ device T
10. WFM_from Disk Software Calibration and Device Specific Functions Each of these software calibration and configuration functions is specific to only one type of device or class of devices Refer to the NI DAQ Function Reference Online Help file to determine which functions your device supports AO Calibrate Calibrate_1200 National Instruments Corporation 3 3 Loads a set of calibration constants into the calibration DACs or copies a set of calibration constants from one of four EEPROM areas to EEPROM area 1 You can load an existing set of calibration constants into the calibration DACs from a storage area in the onboard EEPROM You can copy EEPROM storage areas 2 through 5 EEPROM area 5 contains the factory calibration constants to storage area 1 NI DAQ automatically loads the calibration constants stored in EEPROM area the first time a function pertaining to the AT AO 6 10 is called Calibrates the gain and offset values for the 1200 AI devices ADCs and DACs You can perform a new calibration or use an existing set of calibration constants by copying the constants from their storage location in the onboard EEPROM You can store up to six sets of calibration constants NI DAQ User Manual for PC Compatibles Chapter 3 Software Overview NI DAQ automatically loads the calibration constants stored in EEPROM user area 5 the first time you call a function pertaining to the device Calibrate_TIO Use the functio
11. a measurement of time based on the Julian calendar a commonly used calendar that divides each year into 12 months with 365 days 1 000 samples 1 024 words of memory a software utility that combines object modules created by a compiler and libraries which are collections of object modules into an executable program least significant bit NI DAQ User Manual for PC Compatibles Glossary master slave MB MIO MS MSB multirate scanning mux NC NO OCX output settling time P paging PC NI DAQ User Manual for PC Compatibles Type of network connection in which a request is transmitted to one or more destination nodes and those nodes send a response back to the requesting node In industrial applications the responding slave device is usually a sensor or actuator and the requesting master device is usually a controller megabytes of memory multifunction I O million samples most significant bit scanning different channels at different rates multiplexer a switching device with multiple inputs that sequentially connects each of its inputs to its output typically at high speeds in order to measure several signals with a single analog input channel normally closed normally open OLE Control eXtension Another name for OLE or ActiveX controls reflected by the OCX file extension of ActiveX control files the amount of time required for the analog output voltage to reach its final v
12. e When arising or falling edge occurred on a timing I O line How to Set Up Your DAQ System After you have installed your software and hardware and configured your hardware see Figure 1 1 to begin using NI DAQ in your application programs If you are accessing the NI DAQ device drivers through LabVIEW read the NI DAQ release notes and then use your LabVIEW Online Reference to help you get started using the data acquisition VIs in LabVIEW NI DAQ User Manual for PC Compatibles 1 2 ni com Chapter 1 Introduction to NI DAQ Install your software and hardware according to the instructions in the DAQ Quick Start Guide and if appicable the SCXI Quick Start Guide Yes Are you using LabVIEW Read the LabVIEW Measurements Manual You no longer need the NI DAQ document set Are you using NI DAQ Functions in your application LabWindows CVI Microsoft Visual C Microsoft Visual Basic or Borland C No Read the documentation appropriate for your application software such as VirtualBench ComponentWorks and Measure You no longer need the NI DAQ document set Read the sections of Chapter 2 Fundamentals of Building Windows Applications in this manual that apply to your application development environment Read the appropriate chapters in the DAQ Hardware Overview Guide an online only PDF document Read the sections in Chapter 3 Software Overview in this manua
13. 2 2 1 1 0 0 Least significant bit LSB In the cases where a digital I O port has fewer than eight lines the most significant bits in the byte format are ignored You can configure most of the digital I O ports as either input ports or output ports On the PC TIO 10 653X DSA 671X and E Series devices except for ports 2 3 and 4 on the AT MIO 16DE 10 you can program lines on the same port independently as input or output lines Some digital I O ports are permanently fixed as either input ports or output ports If you configure a port as an input port reading that port returns the value of the digital lines In this case external devices connected to and driving those lines determine the state of the digital lines If no external device is driving the lines the lines float to some indeterminate state and you can read them in either state 0 digital logic low or state 1 digital logic high If you configure a port as an output port writing to the port sets each digital line in the port to a digital logic high or low depending on the data written In this case these digital lines can drive an external device Many of the digital I O ports have read back capability if you configure the port as an output port reading the port returns the output state of that port You can use digital I O ports on the DIO 24 6025E devices and AT MIO 16DE 10 ports 2 and 3 only DIO 96 Lab and 1200 devices 653X DIO 32F PCI 6115 and
14. 3 55 DIO 32F and 653X groups 3 55 to 3 56 PCI 6115 and PCI 6120 groups 3 56 to 3 57 H handshaking mode 3 54 to 3 55 handshaking versus no handshaking digital I O 3 63 hardware support tables 1 4 to 1 6 high level data acquisition functions 3 20 to 3 21 application tips See data acquisition application tips DAQ_Op 3 20 DAQ to_Disk 3 20 Lab_ISCAN_Op 3 20 Lab_ISCAN_to_Disk 3 20 SCAN_Op 3 21 SCAN_to_Disk 3 21 high level waveform generation functions 3 39 WFM_from_Disk 3 39 WFM_Op 3 39 l ICTR_Read function 3 91 ICTR_Reset function 3 91 ICTR_Setup function 3 91 Init_DA_Brds function 3 2 NI DAQ User Manual for PC Compatibles Index initialization and general configuration functions Align _DMA_ Buffer 3 2 Get_DAQ_Device_Info 3 2 Get_NI_DAQ Version 3 2 Init_DA_Brds 3 2 Set_DAQ_Device_Info 3 3 Timeout_Config 3 3 installation See also device configuration flowchart for setting up your system 1 3 setting up your DAQ system 1 2 to 1 3 Inter Range Instrumentation Group IRIG time code protocols 3 97 to 3 98 interval counter timer functions 3 91 to 3 92 application tips 3 92 device support table 3 76 ICTR_Read 3 91 ICTR_Reset 3 91 ICTR_Setup 3 91 interval counter timer operation See also counter timer operation block diagram 3 92 ICTR functions 3 92 IRIG Inter Range Instrumentation Group time code protocols 3 97 to 3 98 L Lab and 1200 series devices counter usage in
15. GF v 1 bridgeConfig 7 FULL_BRIDGE_III strain Ar GF v 1 Vr v 1 Figure 5 1 Strain Gauge Bridge Configuration NI DAQ User Manual for PC Compatibles 5 6 ni com Chapter 5 Transducer Conversion Functions Thermistor_ Convert and Thermistor_Buf_Convert These functions convert a voltage or voltage buffer read from a thermistor into temperature Some SCXI terminal blocks have onboard thermistors that you can use to do cold junction compensation Parameter Discussion Vier is the voltage reference you apply across the thermistor circuit see Figure 5 2 in volts The thermistor on the SCXI terminal blocks has a Viet of 2 5 V R is the value of the resistor in series with your thermistor see Figure 5 2 in ohms The thermistor on the SCXI terminal blocks has an R value of 5 000 Q The TempScale integer indicates in which temperature unit you want your return values to be Constant definitions for each temperature scale are assigned in the conversion header file 1 Celsius 2 Fahrenheit 3 Kelvin 4 Rankine The Thermistor_Convert function has two remaining parameters Volts is the voltage that you read from the thermistor and Temperature is the return temperature value assigned in units determined by TempScale The Thermistor_Buf_Convert function has three remaining parameters numPts is the number of voltage points to convert VoltBuf is the array of voltages that you read from the t
16. Like counters clocks have gate signals that latch their current value or time They can latch a single time or multiple times in a buffer using interrupts or DMA Unlike counters clocks have additional hardware that eliminates drift by synchronizing the clocks to a PPS or IRIG B stream See Figure 3 37 Pa a4 a ae Z Z X GPS Satellite External Signal Gate Satellite Receiver Internal Timebase Source Used for Synchronizing Other Clocks Used for GPCTR Functionality Synch Figure 3 37 Real time Clock Synchronizing to a GPS Receiver Clock Resolution NI TIO based clocks must have a timebase which keeps the clock ticking The default timebase is the 20 MHz internal timebase If your clock has a 20 MHz timebase its resolution will be 50ns 1 50 MHz 50ns National Instruments Corporation 3 95 NI DAQ User Manual for PC Compatibles Chapter 3 Software Overview Clock Synchronization Clocks can be synchronized using an external source Currently there are two supported types of synchronization Pulse Per Second PPS and IRIG B Pulse Per Second PPS the simplest type of synchronization is a very accurate 1 Hz signal Depending on your satellite receiver the accuracy of this signal can vary from 300 to 100 ns The disadvantage of PPS is that no absolute timing information is encoded in the pulse so you must set the initial time of the clock After th
17. ND_CLOCK_x ND_PROGRAM Comment We have programmed the clock Now we need to Comment make sure that the Comment programming was Comment really successful timeAfterProgramming Satellite Receiver Time if timeAfterProgramming lastTime Comment We were successful in programming the clock in Comment time else Comment We didn t make it in time Try again IRIG The Inter Range Instrumentation Group IRIG defines a series of time code protocols which transmit a series of data frames that provide timing information in the binary data of the frame as well as at the start of frame time The clock synchronization uses a subset of the IRIG B protocol for synchronization The IRIG B frame consists of 100 bits each of which is pulse width modulated for 10 ms The resulting data stream repeats once per second with the beginning of the frame marking the 1 second epoch See Figure 3 38 National Instruments Corporation 3 97 NI DAQ User Manual for PC Compatibles Chapter 3 Software Overview Lae facies of A E poas SS 2 Time 091 Days 14 Hours 08 Minutes 32 Seconds Reference Marker 8 mS BCD Time of Year Seconds Minutes Hours gi Y PO PR 1 2 4 8 10 20 40 P11 2 4 8 10 20 40 P2 1 2 4 8 10 20 Binary One 5 mS Binary Zero 2 mS Reference 8mS Figure 3 38 IRIG B Transmission Frame Clock Accuracy Clock accuracy depends on the resolution of th
18. add the following code in the Command1_Click subroutine as follows Redim buffer 10000 GeneralDAQEvent1 ChanStr AIO GeneralDAQEvent1 Refresh refresh to set params ers DAQ Start 1 0 1 buffer s 0 10000 3 10 6 Next define what to do when the DAQ Event occurs In this example we can easily update a text box upon every 1 000 scans and also when the whole acquisition is complete Place a text box on your form It is automatically named Text 1 NI DAQ User Manual for PC Compatibles 3 14 ni com Chapter 3 Software Overview 7 Go to the code window pull down on the Object combo box and select GeneralDAQEvent1 The only Proc for this control object is Fire Within the subroutine enter the following code If DoneFlag lt gt 1 Then Text1 Text acquired Strs Scans amp scans have been Else Textl Text Acquisition is complete ers DAQ Clear 1 End If 8 Make sure that you stop any ongoing acquisition when you stop the program To do so call the DAQ Clear function before the End statement in the subroutine Command2_Click _ Place another button on your form and label it Exit The subroutine should have code as follows er DAQ Clear 1 End 9 Run the program Because you are not going to display the data onto a graph it does not matter what the data is however when you click on the Click Me button the text box should update its contents every second After all the scans are ac
19. avoid long lists of specific devices The Conventions Used in This Manual section of About This Manual lists the devices in each functional type Any device not included in a category will be referred to by its name NI DAQ User Manual for PC Compatibles 1 6 ni com Chapter 1 Introduction to NI DAQ NI DAQ Language Support NI DAQ supplies header files examples and instructions on how to use an Integrated Development Environment IDE for one of the following languages under Windows 2000 NT 98 95 e Microsoft Visual C 4 X 5 0 or 6 0 e Visual Basic 4 0 32 bit 5 0 or 6 0 e Borland C 5 X NI DAQ also provides an NI DAQ function prototype file for use with Borland Delphi 2 32 bit 3 and 4 Most of the files on the release media are compressed Always run the NI DAQ installation utilities to extract the files you want For a brief description of the directories produced by the install programs and the names and purposes of the uncompressed files consult the NI DAQ Readme File Start Programs National Instruments DAQ NI DAQ Readme File Device Configuration Before you begin your NI DAQ application development you must configure your National Instruments DAQ devices which can be plug in devices PC cards PCMCIA or external devices you connect to the parallel port of your computer NI DAQ needs the device configuration information to program your hardware properly Using Measurement amp Automation Explor
20. counter BO provides the same timebase for data acquisition and waveform generation NI DAQ User Manual for PC Compatibles 3 24 ni com Chapter 3 Software Overview DAQCard 500 700 516 Device and LPM Device Counter Timer Signals For these devices counter 0 produces the sample interval for data acquisition timing If data acquisition is not in progress you can call the ICTR functions to use counter 0 as a general purpose counter Because the CLOCKO input is connected to a 1 MHz oscillator the timebase for counter 0 is fixed External Multiplexer Support AMUX 64T You can expand the number of analog input signals measurable by the MIO and AI devices with an external multiplexer device AMUX 64T Refer to the AMUX 64T External Multiplexer Devices chapter in the DAQ Hardware Overview Guide for more information on using the AMUX 64T with your MIO and AI device See the AMUX 64T User Manual for more information on the external multiplexer device Basic Building Blocks Most of the buffered data acquisition applications are made up of four building blocks as shown in Figure 3 3 However depending on the specific devices and applications you have the NI DAQ functions comprising each building block vary Typical applications can include the NI DAQ functions in each of their four building blocks Configuration Start Checking Cleaning up Figure 3 3 Buffered Data Acquisition Basic Building Blocks
21. hardware a property of an event that occurs at an arbitrary time without synchronization to a reference clock 2 software an action or event that occurs at an unpredictable time with respect to the execution of a program Data is acquired by a DAQ system while another program or processing routine is running without apparent interruption the range of frequencies present in a signal or the range of frequencies to which a measuring device can respond G 2 ni com base address BCD BIOS bipolar bit block mode bus byte C C CI cold junction compensation compiler conversion time counter timer National Instruments Corporation G 3 Glossary A memory address that serves as the starting address for programmable registers All other addresses are located by adding to the base address binary coded decimal basic input output system a signal range that includes both positive and negative values for example 5 V to 5 V One binary digit either 0 or 1 a high speed data transfer in which the address of the data is sent followed by a specified number of back to back data words The group of conductors that interconnect individual circuitry in a computer Typically a bus is the expansion vehicle to which I O or other devices are connected Examples of PC buses are the PCI bus AT bus and EISA bus Eight related bits of data an 8 bit binary number Also used to denote the amount of memory re
22. initiate the process 7 Call DIG _Block_ Clear after the pattern generation completes Because DIG_Block_ Clear unaligns the buffer you can access the digital input pattern generation as you can with an unaligned buffer To use the same buffer again for digital output pattern generation you must call Align DMA Buffer again Double Buffered 1 0 With the double buffered DIG_DB digital I O functions you can input or output unlimited digital data without requiring unlimited memory Double buffered digital I O is useful for applications such as streaming data to disk and sending long data streams as output to external devices For an explanation of double buffering refer to Chapter 4 NI DAQ Double Buffering Digital double buffered output operations have two options The first option is to stop the digital block operation if old data is ever encountered This occurs if the DIG_DB Transfer function calls are not keeping pace with the data input or output rate that is new data is not transferred to or from the circular buffer quickly enough For digital input this option prevents the loss of incoming data For digital output this option prevents erroneous data from being transferred to an external device If the group is configured for handshaking an old data stop is only a pause and a call to one of the transfer functions resumes the digital operation If the group is configured for pattern generation an old data stop forces you to c
23. progress Remember NI DAQ requires some time after the final transfer to actually output the data National Instruments Corporation 3 47 NI DAQ User Manual for PC Compatibles Chapter 3 Software Overview The final step is to call WFM_Group_Control operation CLEAR The CLEAR operation performs all of the necessary cleanup work after a waveform generation Additionally CLEAR halts any ongoing waveform generation y Enable double buffering WFM_DB_Config y Assign channels to waveform generation group WFM_Group_Setup Load waveform buffer and specify iterations WFM_ Load Set the update rate WFM_ClockRate or WFM Set Clock Start background waveform generation WFM_Group_ Control operation START Check if the next half buffer is ready for data No WFM DB HalfReady Transfer the next half of the data to the waveform data buffer WFM_DB Transfer Do you want to transfer more data to the waveform buffer Any more data to output Clear the waveform WFM_Group_ Control operation CLEAR Figure 3 17 Double Buffered Waveform Generation NI DAQ User Manual for PC Compatibles 3 48 ni com Chapter 3 Software Overview Reference Voltages for Analog Output Devices Table 3 4 shows the output voltages produced when you select unipolar output polarity Table 3 4 Output Voltages with Unipolar Output Polarity Value in
24. to use a buffer of memory You can use the memory handle returned by GlobalLock in place of the buffer parameter in NI DAQ API functions that accept buffers Align _DMA Buffer DAQ DB Transfer DAQ Monitor DAQ Op DAQ Start DIG Block _In DIG Block _Out DIG _DB Transfer GPCTR_Config Buffer GPCTR_Read Buffer Lab _ISCAN Op Lab ISCAN Start SCAN Op SCAN Start SCAN Sequence Demux WFM_DB Transfer WFM_Load WFM_Op After using the memory unlock memory with GlobalUnlock and free it with GlobalFree Sy Note If you allocate memory from GlobalAlloc you must call GlobalLock on the memory object before passing it to NI DAQ String Passing To pass strings pass a pointer to the first element of the character array Be sure that the string is null terminated Parameter Passing By default C passes parameters by value Remember to pass pointers to variables when you need to pass by address National Instruments Corporation 2 3 NI DAQ User Manual for PC Compatibles Chapter 2 Fundamentals of Building Windows Applications Creating a Windows Application Using Microsoft Visual Basic This section assumes that you will be using the Microsoft Visual Basic IDE to manage your code development and that you are familiar with the IDE Developing an NI DAQ Application To develop an NI DAQ application follow these general steps 1 Open an existing or new Visual Basic project to manage your application code
25. y Configure lines for input Optional on 652X devices Configure ports for input DIG Line_Config DIG Prt_Config y v DIG In Line DIG In Prt No Yes Figure 3 19 Basic Digital Filtering of Input Data Application The first step is to call DIG_Filter_Config which enables filtering on the specified lines Next you can configure either the ports or the lines For the 652X devices configuring the ports by calling DIG_Prt_Config is optional because the ports have fixed directions DIG_Line_Config is also optional because the lines within the ports have fixed directions The next step is to call DIG_In_Port to read data from an input port Call DIG_In_Line to read a bit from a line The final step is to loop back if more data is to be read Digital 1 0 Application Tips This section gives a basic explanation of how to construct an application using the digital input and output functions The flowcharts are a quick reference for constructing potential applications from the NI DAQ function calls NI DAQ User Manual for PC Compatibles 3 62 ni com Chapter 3 Software Overview Handshaking Versus No Handshaking Digital 1 0 Digital ports can output or input digital data in two ways The first is to immediately read or write data to or from the port This type of digital I O is called no handshaking mode The second method is to coordinate digital data transfers with another
26. 32HS DAQCard 6533 PXI 6533 PCI 6534 and PXI 6534 Refers to the DAQCard 6601 PCI 6601 PCI 6602 PXI 6602 PCI 6608 and PXI 6608 Refers to the PCI 6602 and PXI 6602 Refers to the DAQCard 6715 PCI 6711 PXI 6711 PCI 6713 and PXI 6713 These analog input devices are listed in Table 1 Bold text denotes items that you must select or click on in the software such as menu items and dialog box options Bold text also denotes parameter names and function prototypes Refers to the DAQCard 500 and DAQCard 700 NI DAQ User Manual for PC Compatibles X ni com DIO device DIO 24 DIO 32F DIO 96 DSA device E Series device italic Lab and 1200 analog output device Lab and 1200 device LPM device MIO device MIO 16XE 50 device MIO 64 monospace monospace bold National Instruments Corporation xi About This Manual Refers to any DIO 24 DIO 32 DIO 6533 or DIO 96 Refers to the PC DIO 24 PC DIO 24PnP DAQCard DIO 24 PCI 6503 Refers to the AT DIO 32F Refers to the PC DIO 96 PC DIO 96PnP PCI DIO 96 DAQPad 6507 DAQPad 6508 and PXI 6508 Refers to the NI 4451 for PCI NI 4452 for PCI NI 4454 for PCI NI 4551 for PCI NI 4552 for PCI and NI 4472 for PXI CompactPCI dynamic signal acquisition devices These are MIO and AI devices Refer to Table 1 for a complete list of these devices Italic text denotes variables emphasis a cross reference or an introduction to a key concept This fo
27. MIO 16E 1 PC AO 2DC PC OPDIO 16 AT MIO 16E 2 PC DIO 24 PC TIO 10 AT MIO 16E 10 AT MIO 16XE 10 AT MIO 16XE 50 AT MIO 64E 3 AT DIO 32HS PC DIO 24PnP Table 1 2 NI DAQ Version 6 9 Plug in Device Support for PCI Buses PCI NI 4451 for PCI PCI DIO 96 PCI 6115 NI 4452 for PCI PCI 1200 PCI 6120 NI 4454 for PCI PCI 6023E PCI 6503 NI 4551 for PCI PCI 6024E PCI 6527 NI 4552 for PCI PCI 6025E PCI 6534 NI 6222 for PCI PCI 6031E MIO 64XE 10 PCI 6602 PCI MIO 16E 1 PCI 6032E AI 16XE 10 PCI 6608 PCI MIO 16E 4 PCI 6033E AI 64XE 10 PCI 6703 PCI MIO 16XE 10 PCI 6052E PCI 6704 PCI 6034E PCI 6071E MIO 64E 1 PCI 6711 PCI 6035E PCI 6110E PCI 6713 PCI MIO 16XE 50 PCI 6111E PCI 4452 PCI DIO 32HS NI DAQ User Manual for PC Compatibles ni com Chapter 1 Introduction to NI DAQ Table 1 3 NI DAQ Version 6 9 Plug in Device Support for PXI Buses PXI NI 4472 for PXI CompactPCI PXI 6035E PXI 6527 NI 6222 for PXI PXI 6040E PXI 6533 PXI 6023E PXI 6052E PXI 6534 PXI 6024E PXI 6070E PXI 6602 PXI 6025E PXI 6071E PXI 6608 PXI 6030E PXI 6115 PXI 6703 PXI 6031E PXI 6120 PXI 6704 PXI 6034E PXI 6508 Table 1 4 NI DAQ Version 6 9 Plug in Device Support for PC Card CardBus and VXI Buses PC Card CardBus VXI DAQCard 500 DAQCard 6533 DAQCard 6601 VXI MIO 64E 1 DAQCard 516 DAQCard 6715 DAQCard 6533 VXI MIO 64XE 10 DAQCard 700 DAQCard AI 16E 4 VXI DIO 128 DAQCard 1200 DAQCard AI 16XE 50 VXI A
28. Overview Asynchronous start functions include DAQ Start SCAN Start and Lab_ISCAN Start Figures 3 6 and 3 7 show how the start calls make up building block 2 for different devices sample timebase and Convert sampling rate to l sample interval DAQ Rate Sample multiple Select channels and channels their gain for multiple channel scanning SCAN Setup Initiate multiple channel data acquisition DAQ Start Initiate single channel data acquisition SCAN Start Figure 3 6 Buffered Data Acquisition Application Building Block 2 Start for the MIO Al and DSA Devices For DSA devices substitute DAQ_Set_Clock for DAQ Rate in Figure 3 6 DAQ Rate will not produce the correct clock settings for DSA devices If your device works with multirate scanning you can use SCAN Sequence Setup instead of SCAN Setup in building block 2 NI DAQ User Manual for PC Compatibles 3 28 ni com Chapter 3 Software Overview sample timebase and Convert sampling rate to sample interval DAQ Rate Sample multiple channels Initiate multiple channel Initiate single channel data acquisition data acquisition Lab_ISCAN Start DAQ Start Figure 3 7 Buffered Data Acquisition Application Building Block 2 Start for the 516 Devices DAQCard 500 700 Lab and 1200 Devices and LPM Devices When you have the asynchronous start calls in your building block 2 the next
29. PCI 6120 devices for handshaking and no handshaking modes These two modes have the following characteristics e No handshaking mode This mode changes the digital value at an output port when written to and returns a digital value from a digital input port when read from No handshaking signals are generated e Handshaking mode This mode is for digital I O handshaking that is a digital input port latches the data present at the input when the port receives a handshake signal and generates a handshake pulse when the computer writes to a digital output port In this mode you can read the status of a port or a group of ports to determine whether an external device has accepted data written to an output port or has latched data NI DAQ User Manual for PC Compatibles 3 54 ni com Chapter 3 Software Overview into an input port The handshaking mode for the PCI 6115 and the PCI 6120 is slightly different and is more appropriately called a clocking mode In the clocking mode no two way handshaking signals are generated Instead data is latched in or latched out when a pulse from a clock signal is detected 3 Note On the 653X DIO 32F PCI 6115 and PCI 6120 devices you must assign ports to a group before you can use handshaking mode Process control applications such as controlling or monitoring relays often use the no handshaking mode Communications applications such as transferring data between two computers often use the handshaki
30. Software Overview Another type of gated pulse generation can be called retriggerable one shot pulse where a signal pulse is produced in response to a hardware trigger To do this call CTR_Config and specify edge gating Connect your trigger signal to the GATE input Call CTR_Square to specify your pulse Subsequently each edge sent to the GATE input produces one cycle of the square wave Besides CTR_Square you also can call CTR_FOUT_Config to generate a square wave The advantage of using CTR_FOUT_Config is that it does not use a counter to generate the square wave It uses a different built in feature of the counter timer chip However unlike CTR_Square CTR_FOUT_Config can only generate a square wave with a 50 percent duty cycle NI DAQ has a number of utility functions that give you more control over the counters CTR_State is for checking the logic level of any counter output CTR_Reset halts any operation on a counter and puts the counter output to a known state CTR_Stop and CTR_Restart stop and restart any operation on a counter CTR_Simul_Op simultaneously can start stop and restart any number of counters Also CTR_Simul_Op simultaneously can save all the current counter values to their hold registers which you can read later one at a time See Figure 3 30 on how to incorporate CTR_Simul_Op with other counter functions like CTR_EvCount and CTR_Pulse NI DAQ User Manual for PC Compatibles 3 84 ni com Chapter 3 Software O
31. The values used for a b and c are shown below These values are correct for the thermistors provided on the SCXI terminal blocks If you are using a thermistor with different values for a b and c consult you thermistor NI DAQ User Manual for PC Compatibles 5 8 ni com Chapter 5 Transducer Conversion Functions data sheet you can edit the thermistor conversion routine to use your own a b and c values a 1 295361E 3 b 2 343159E 4 c 1 018703E 7 Figure 5 2 Circuit Diagram of a Thermistor in a Voltage Divider Thermocouple_Convert and Thermocouple_Buf_Convert These functions convert a voltage or voltage buffer that NI DAQ read from a thermocouple into temperature Parameter Discussion The TCType integer indicates what type of thermocouple NI DAQ used to read the temperature Constant definitions for each thermocouple type are shown in the conversion header file You can use the constants that have been defined or you can pass integer values to the routine 1 E ont ON BR WH LP Z0 awp National Instruments Corporation 5 9 NI DAQ User Manual for PC Compatibles Chapter 5 Transducer Conversion Functions CJCTemp is the temperature in Celsius that NI DAQ uses for cold junction compensation of the thermocouple temperature If you are using SCXI most likely this is the temperature that NI DAQ read from the temperature sensor on the SCXI terminal block The AMUX 64T also has a temperature sen
32. Visual Basic 2 4 to 2 6 Microsoft Visual C 2 2 to 2 3 NI DAQ examples 2 9 to 2 10 NI DAQ libraries 2 1 NI DAQ User Manual for PC Compatibles l 2 C Calibrate_1200 function 3 3 to 3 4 Calibrate_DSA function 3 4 Calibrate_E_ Series function 3 4 Calibrate_TIO function 3 4 calibration functions See software calibration and device specific functions clocks or time counters for NI TIO devices 3 95 to 3 102 accuracy 3 98 clock resolution 3 95 example clock in measurement system 3 98 to 3 99 sample use cases 3 99 to 3 102 synchronization 3 96 to 3 97 IRIG Inter Range Instrumentation Group protocols 3 97 to 3 98 pulse per second 3 96 to 3 97 real time clock synchronizing to GPS receiver figure 3 95 sample code for setting up clock using PPS 3 96 to 3 97 concatenated event counting 3 88 to 3 89 Config_Alarm_Deadband function 3 5 Config_ATrig_Event_Message function 3 5 Config _DAQ_ Event_Message function 3 5 configuration NI DAQ hardware support tables 1 4 to 1 6 using Measurement amp Automation Explorer 1 7 configuration functions See also initialization and general configuration functions AI_Change_Parameter 3 16 AI_Configure 3 16 AI_Mux_Config 3 17 AI_Setup 3 17 AO_Configure 3 35 Config_Alarm_Deadband 3 5 Config_ATrig_Event_Message 3 5 ni com Config _DAQ_Event_Message 3 5 Configure_HW_Analog_Trigger 3 4 CTR_Config 3 77 CTR_FOUT_Config 3 77 DAQ Config 3 21 DAQ_DB_ Config
33. Waveform Buffer Device 0 4 095 65 535 AT MIO 16X AT MIO 16XE 10 OV Reference PCI MIO 16XE 10 PCI MIO 16XE 50 voltage PCI 6031E MIO 64XE 10 VXI MIO 64XE 10 6052E 6053E devices All other MIO devices OV Reference voltage AT AO 6 10 OV Reference voltage 10 V in default case Lab and 1200 devices with analog output OV 5 V Table 3 5 shows the output voltages produced when you select bipolar output polarity Table 3 5 Output Voltages with Bipolar Output Polarity Value in Waveform Buffer 2 047 32 768 Device 2 048 32 767 AT MIO 16XE 10 PCI MIO 16XE 10 PCI MIO 16XE 50 PCI 6031E MIO 64XE 10 VXI MIO 64XE 10 PCI 6110E PCI 6111E 6052E 6053E devices Negative of the reference voltage Reference voltage All other MIO devices 671X devices 622XI devices Negative of the reference voltage Reference voltage National Instruments Corporation NI DAQ User Manual for PC Compatibles Chapter 3 Software Overview Table 3 5 Output Voltages with Bipolar Output Polarity Continued Value in Waveform Buffer Device 2 048 2 047 32 768 32 767 AT AO 6 10 Negative of Reference the reference voltage voltage 10 V in 10 Vin default case default case 3 NI DAQ User Manual for PC Compatibles Lab and 1200 devices with analog output Note NI 4451 left justif
34. Yes Another reading No Terminate event counting CTR_Reset Figure 3 28 Event Counting NI DAQ User Manual for PC Compatibles 3 82 ni com Chapter 3 Software Overview Another major category of counter functions is pulse generation With the NI DAQ counter functions you can call CTR_Pulse to generate a pulse or CTR_Square to generate a train of pulses a square wave To generate a pulse or a square wave see Figure 3 29 for details on the function flow When CTR_Square is used with special gating gateMode 8 you can achieve gate controlled pulse generation When the gate input is high NI DAQ uses period1 to generate the pulses When the gate input is low NI DAQ uses period2 to generate the pulses If the output mode is TC Toggled the result is two 50 percent duty square waves of different frequencies If the output mode is TC Pulse the result is two pulse trains of different frequencies Configure the pulse counter CTR_Config gt Yes No Single pulse generation Convert frequency to timebase and period intervals Generate a pulse y E CTR_Rate CTR_ Pulse Start pulse train generation CTR_Square Yes Generate a new pulse or a new pulse train No Terminate pulse generation CTR Reset Figure 3 29 Pulse Generation National Instruments Corporation 3 83 NI DAQ User Manual for PC Compatibles Chapter 3
35. appears inverted In Figure 3 27 the counter is configured to count the signal output changes state with respect to the rising edge of the timebase Programmable Frequency Output Operation The PC TIO 10 provides two 4 bit programmable frequency output signals The signals are divided down versions of the selected timebase Any of five internal timebases counter SOURCE inputs and counter GATE inputs can be selected as the FOUT source See the CTR_FOUT_Config function description in the NI DAQ Function Reference Online Help file for FOUT use and timing information National Instruments Corporation 3 81 NI DAQ User Manual for PC Compatibles Chapter 3 Software Overview Counter Timer Application Tips All NI DAQ counter timer functions can be broken down into two major categories event counting functions and pulse generation functions On top of those functions NI DAQ has utility functions CTR_EvCount and CTR_EvRead are the two functions designed for event counting See Figure 3 28 for basic building blocks of event counter applications Also read Event Counting Applications later in this chapter for details y Configure the EvCount counter CTR_Config li See Event Counting Applications for details on CTR_EvCount and CTR_Period Continuous counting on active gate signals y Start counting y Start counting CTR_EvCount CTR_Period g Retrieve count value CTR_EvRead
36. building block Checking is very useful for determining the status of the ongoing data acquisition process National Instruments Corporation 3 29 NI DAQ User Manual for PC Compatibles Chapter 3 Software Overview Building Block 3 Checking DAQ Check and Lab_ISCAN_ Check shown in Figures 3 8 and 3 9 are simple and quick ways to check the ongoing data acquisition process This call is often put in a while loop so that the application can periodically monitor the data acquisition process multiple channel Check ongoing single or p data acquisition status DAQ Check Data Acquisition complete y Yes Figure 3 8 Buffered Data Acquisition Application Building Block 3 Checking for the MIO Al and DSA Devices Lab_ISCAN Check DAQ Check Sample multiple channels Check ongoing single channel data acquisition status Check ongoing multiple channel data acquisition status Y NI DAQ User Manual for PC Compatibles 3 30 Figure 3 9 Buffered Data Acquisition Application Building Block 3 Checking for the 516 Devices DAQCard 500 700 Lab and 1200 Devices and LPM Devices ni com Chapter 3 Software Overview However if the information provided by DAQ_ Check is not sufficient DAQ Monitor or the double buffered functions might be a better choice With DAQ Monitor not only can you monitor the data acquisition process but you can also retrieve a port
37. control call One or more channels can be read while the module is in hold mode After you put the module back into track mode you can repeat the process to acquire new data Remember that the channel and gain parameters of the AI function calls refer to the DAQ device channels and gains Simply use the data acquisition channels that correspond to the module channels you want as described earlier in this section Also be aware of the SSH Track Hold timing requirements described in the SCXI 1530 1531 section of the SCXT Hardware chapter in the DAQ Hardware Overview Guide Figure 3 46 shows the function call sequence of a channel scanning application using an SSH module in parallel mode Configure the desired module for interval scanning SCXI_Track_Hold_ Setup Acquire data from the desired channels using interval scanning with the SCAN and Lab_ISCAN functions Scanned Data Acquisition Have you acquired all the data you need Yes Disable the Track Hold setup of the module to free the counter resource on the data acquisition board SCXI_Track_Hold_ Setup Figure 3 46 Channel Scanning Operation Using an SSH Module in Parallel Mode National Instruments Corporation 3 123 NI DAQ User Manual for PC Compatibles Chapter 3 Software Overview The call sequence is much simpler because the scan interval timer automatically controls the Track Hold state of the module during the i
38. counter The time lapse from the edge is then equal to event count timebase period If counters are to be concatenated for time lapse measurement use level gating where the GATE input signal goes active at the starting event and stays active Frequency measurement is a special case of event counting that is you can measure the frequency of an input signal by counting the number of signal edges that occur during a fixed amount of time For this application connect the signal to be measured to the SOURCE input of the counter and select the appropriate timebase if ctr 1 connect the signal to SOURCE1 and use timebase 6 Count either low to high or high to low edges this feature is selected by edgeMode in the CTR_Config function Using level gating and applying a gate pulse of a known fixed duration to the GATE input of the counter constrains event counting to a fixed amount of time The average frequency of the incoming signal is then equal to event count gate pulse width Another counter can supply the gating pulse for frequency measurement by connecting the OUT signal from the counter producing the gating pulse to the GATE input of the counter doing the counting see the CTR_ Pulse function description in the NI DAQ Function Reference Online Help file for more information Figure 3 33 illustrates a frequency measurement National Instruments Corporation 3 87 NI DAQ User Manual for PC Compatibles Chapter 3 Software Overvi
39. counter block diagram 3 78 counter timing and output types figure 3 81 programmable frequency output operation 3 81 data acquisition function application tips 3 24 to 3 25 interval counter timer operation 3 92 counter usage in waveform generation 3 50 to 3 51 CTR_Config function 3 77 CTR_EvCount function 3 77 CTR_EvRead function 3 77 NI DAQ User Manual for PC Compatibles l 4 CTR_FOUT_Config function 3 77 CTR_Period function 3 77 CTR_Pulse function 3 77 CTR_Rate function 3 77 CTR_Reset function 3 77 CTR_ Restart function 3 77 CTR_Simul_Op function 3 77 CTR_Square function 3 77 CTR_ State function 3 78 CTR_Stop function 3 78 customer education A 1 D DAQ system setting up 1 2 to 1 3 DAQCard 500 700 devices data acquisition application tips 3 25 interval counter timer operation 3 91 to 3 92 DAQ Check function 3 21 DAQ Clear function 3 21 DAQ Config function 3 21 DAQ_DB_ Config function 3 23 4 10 DAQ_DB_HalfReady function 3 24 4 12 DAQ_DB_ Transfer function 3 24 4 11 DAQ Monitor function 3 21 DAQ_Op function 3 20 DAQ _ Rate function 3 22 DAQ Set_clock function 3 22 DAQ Start function 3 22 DAQ StopTrigger_Config function 3 22 DAQ_to_Disk function 3 20 DAQ_VScale function 3 22 data acquisition application tips 3 24 to 3 32 basic building blocks 3 25 to 3 26 building block 1 configuration functions 3 26 building block 2 start functions 3 27 to 3 29 building block 3 check func
40. counter value is latched to the Hold Register until the gate signal becomes inactive To detect the counter overflow feed the output of the pulse width measurement counter to the source input of an event counting counter If the event counting counter value is not zero after the pulse width measurement the pulse width measurement is not correct Interval Counter Timer Functions The Interval Counter Timer functions perform interval timing I O and counter operations on the 516 devices DAQCard 500 700 Lab and 1200 devices and LPM devices Refer to the NI DAQ Function Reference Online Help file to determine which functions your device supports ICTR_Read Returns the current contents of the selected counter without disturbing the counting process and returns the count ICTR_Reset Sets the output of the selected counter to the specified state ICTR_Setup Configures the assigned counter to operate in the specified mode National Instruments Corporation 3 91 NI DAQ User Manual for PC Compatibles Chapter 3 Software Overview Interval Counter Timer Operation for the ICTR Functions Figure 3 35 shows the 16 bit counters available on the 516 devices DAQCard 500 700 Lab and 1200 devices and LPM devices CLK Counter OUT GATE Figure 3 35 Interval Counter Block Diagram Each counter has a CLK input a GATE input and an OUT output signal Use a counter to count the falling
41. digital port The second method is called digital T O with handshaking With handshaking you use dedicated transmission lines to ensure that data on the receiving end is not overwritten with new data before it is read from the input port NI DAQ supports both handshaking and no handshaking modes The application outlines within this section explain the use of both modes where they apply Digital Port I O Applications Digital port I O applications use individual digital ports to input or output digital data In addition the applications input or output data points on an individual basis You can configure individual port transfers for handshaking or no handshaking All AT and PC devices with digital I O ports can use no handshaking digital port I O DIO 24 6025E devices AT MIO 16DE 10 DIO 96 and Lab and 1200 devices can also execute handshaking digital I O for using the port I O functions Figure 3 20 illustrates the series of calls for digital port I O applications with handshaking Figure 3 21 illustrates the series of calls for digital port T O applications without handshaking National Instruments Corporation 3 63 NI DAQ User Manual for PC Compatibles Chapter 3 Software Overview Configure ports for input or output Enable optional handshaking DIG Prt_Config P Check for port ready if handshaking is enabled Not Ready DIG _Prt_Status Ready Input data from port
42. files follow the steps mentioned above in Developing an NI DAQ Application In place of nidaq h make sure you include nidagex h Also make sure you include the import library nidex32b 1ib into your project in addition to nidaq32b 1ib Refer to the NI DAQ Examples Help Start Programs National Instruments DAQ NI DAQ Examples Help for additional information regarding NI DAQ examples Special Considerations Refer to Special Considerations in the Creating a Windows Application Using Microsoft Visual C section Using Borland Delphi with NI DAQ The NI DAQ installer installs a prototype file for use with Borland Delphi 2 0 or later which is stored in the Include directory in your NI DAQ directory To use this prototype file include the file nidaq pas into your Borland Delphi project and be sure to include this line in your Delphi source code uses NIDAQ Sy Note There are no examples written with the NI DAQ API for Borland Delphi For examples on NI DAQ function flow refer to the examples of other languages and the flowchart in Chapter 3 Software Overview Refer to the note at the end of the NI DAQ Examples section of this chapter for information on examples using ComponentWorks ActiveX controls NI DAQ User Manual for PC Compatibles 2 8 ni com Chapter 2 Fundamentals of Building Windows Applications NI DAQ Examples The NI DAQ installer installs a suite of concisely written examples in the following application deve
43. for PC Compatibles 3 124 ni com Chapter 3 Table 3 12 Maximum SCX Module Settling Times Software Overview Settling Time Settling Time Settling Time Using Using Using up to Settling Time AT MIO 16XE 10 AT MIO 16XE 10 12 bit 200 kS s Using 0 006 0 0015 SCXI Module Gain Device AT MIO 16E 22 Accuracy Accuracy SCXI 1100 1 to 100 7 us 4 us 10 us 32 us no filter 200 10 us 5 5 us 10 us 33 us 500 16 us 12 us 25 us 40 us 1 000 50 us 20 us 30 us 76 us 2 000 50 us 25 us 30 us 195 us SCXI 1102 B C all gains 7 us 3 us 10 us VXI SC 1102 B C SCXI 1104 C SCXI 1112 SCXI 1120 all gains 7 us 3 us 10 us 20 us SCXI 1120D SCXI 1125 SCXI 1121 all gains 7 us 3 us 10 us 20 us SCXI 1122 all gains 10 ms 10 ms 10 ms 10 ms SCXI 1126 all gains 7 us 3 us 10 us 20 us or ranges SCXI 1140 all gains 7 us 3 us 10 us 20 us SCXI 1141 all gains 7 us 3 us 10 us 20 us SCXI 1142 SCXI 1143 SCXI 1520 SCXI 1540 1 Includes effects of a 12 bit 200 kS s device with 1 m SCXI cable assembly 2 Includes effects of AT MIO 16E 2 with 1 or 2 m SCXI cable assembly 3 Includes effects of AT MIO 16XE 10 with 1 or 2 m SCXI cable assembly Note If you are using remote SCXI the maximum data acquisition rate also depends on the serial baud rate used For more information see your SCXI user manual National Instruments Corporation 3 125 NI DAQ User Manual for PC Compatibl
44. for PCI NI 4454 for PCI NI 4551 for PCI NI 4552 for PCI and NI 4472 for PXI CompactPCI NI DAQ User Manual for PC Compatibles xii ni com About This Manual track and hold Refers to the SCXI 1140 SCXI 1520 SCXI 1530 and SCXI 1531 module VXI MIO device Refers to the VXI MIO 64E 1 and VXI MIO 64XE 10 VXI SC 1102 B C Refers to the VXI SC 1102 VXI SC 1102B and VXI SC 1102C MIO and Al Device Terminology This manual uses generic terms to describe groups of devices whenever possible The generic terms for the MIO and AI devices are based on the number of bits the platform and the functionality These devices are also collectively known as E Series devices The following table lists each MIO and AI device and the possible classifications for each Table 1 MIO and Al Device Classifications Number of SE Device Channels Bit Type Functionality AT AI 16XE 10 16 16 bit AT Al AT MIO 16DE 10 16 12 bit AT MIO AT MIO 16E 1 16 12 bit AT MIO AT MIO 16E 2 16 12 bit AT MIO AT MIO 16E 10 16 12 bit AT MIO AT MIO 16F 5 16 12 bit AT MIO AT MIO 16XE 10 16 16 bit AT MIO AT MIO 16XE 50 16 16 bit AT MIO AT MIO 64E 3 64 12 bit AT MIO DAQCard 6023E 16 12 bit PCMCIA Al DAQCard 6024E 16 12 bit PCMCIA MIO DAQCard 6062E 16 12 bit PCMCIA MIO DAQCard AI 16E 4 16 12 bit PCMCIA Al DAQCard AI 16XE 50 16 16 bit PCMCIA Al DAQPad MIO 16XE 50 16 16 bit Parallel Port MIO DAQPad 6020E 16 12
45. from your application Notice that Figure 4 4d is equivalent to the step in Figure 4 4b and is the start of a two step cycle Potential Setbacks Like double buffered input double buffered output has two potential problems The first is the possibility of the output device retrieving and outputting the same data before NI DAQ has updated the circular buffer with new data from the transfer buffer This situation is illustrated by Figure 4 5 Notice in Figure 4 5b NI DAQ has missed the opportunity to copy data from the transfer buffer to the first half of the circular buffer while the output device is retrieving data from the second half As a result the device begins to output the original data in the first half of the circular buffer before NI DAQ has updated it with data from the transfer buffer Figure 4 5c To guarantee uncorrupted output data NI DAQ is forced to wait until the device finishes retrieving data from the first half before copying the data from the transfer buffer After the device has begun to output the second half NI DAQ copies the data from the transfer buffer to the first half of the circular buffer Figure 4 5d National Instruments Corporation 4 7 NI DAQ User Manual for PC Compatibles Chapter 4 NI DAQ Double Buffering Outgoing Device Data T Circular Buffer i Transfer Buffer y Overwrite Before A ad Empty Buffer Untransferred Data T
46. function descriptions in the NI DAQ Function Reference Online Help file the count parameter descriptions specify that count must be an integer multiple of the total number of channels scanned In channel scanning acquisitions in parallel mode the total number of channels scanned is the numChans parameter in the SCAN Setup SCAN Op SCAN to Disk Lab ISCAN Start Lab_ISCAN Op or Lab _ISCAN_ to Disk function calls NI DAQ User Manual for PC Compatibles 3 120 ni com Chapter 3 Software Overview When you use the SCXI 1200 module in parallel mode you simply use the AI DAQ or Lab_ISCAN functions described earlier in this chapter with the logical device number you assigned in Measurement amp Automation Explorer You cannot use the SCXI 1200 to read channels from other analog input modules that are configured for parallel mode The SCXI 1100 SCXI 1101 SCXI 1102 B C VXI SC 1102 B C SCXI 1104 C SCXI 1112 SCXI 1122 and SCXI 1540 operate in multiplexed mode only The SCXI 1140 SCXI 1520 SCXI 1530 and SCXI 1531 modules require the use of SCX functions to configure and control the Track Hold state of the module before you can use the AI DAQ SCAN and Lab_ISCAN functions to acquire the data Figure 3 45 shows the function call sequence of a single channel or software scanning operation using these modules in parallel mode National Instruments Corporation 3 121 NI DAQ User Manual for PC Compatibles Chapter 3 Software Overview
47. settings threshold or hysteresis or with the SCXI 1102 B C to determine if the module has settled after changing gains Loads the SCXI chassis configuration information that you established in the Measurement amp Automation Explorer Sets the software states of the chassis and modules present to their default states No changes are made to the hardware states of the SCXI chassis or modules Reads the Module ID register of the SCXI module in a given slot The principal difference between this function and SCXI_Get_Module_Info is that SCXI_ModuleID_Read does a hardware read of the module You can use this function to verify that your SCXI system is configured and communicating properly NI DAQ User Manual for PC Compatibles Chapter 3 Software Overview SCXI_MuxCtr_Setup SCXI_Reset SCXI_Scale SCXI_SCAN_ Setup SCXI_Set_Config SCXI_Set_Excitation NI DAQ User Manual for PC Compatibles 3 110 Enables or disables a DAQ device counter to be used as a multiplexer counter during SCXI channel scanning to synchronize the scan list with the module scan list that NI DAQ has downloaded to Slot 0 of the SCXI chassis Resets the specified module to its default state You can also use SCXI_Reset to reset the Slot 0 scanning circuitry or to reset the entire chassis Scales an array of binary data acquired from an SCXI channel to voltage Sets up the SCXI chassis for a multiplexed scanning data acquisition opera
48. start and stop the counter operation There are nine gating modes available in the Am9513 National Instruments Corporation No Gating Counter is started and stopped by software High Level Gating Counter is active when its gate input is at high logic state The counter is suspended when its gate input is at low logic state Low Level Gating Counter is active when its gate input is at low logic state The counter is suspended when its gate input is at high logic state Rising Edge Gating Counter starts counting when it receives a low to high edge at its gate input Falling Edge Gating Counter starts counting when it receives a high to low edge at its gate input High Terminal Count Gating Counter is active when the next lower order counter reaches terminal count TC and generates a TC pulse High Level Gate N 1 Gating Counter is active when the gate input of the next higher order counter is at high logic state Otherwise the counter is suspended High Level Gate N 1 Gating Counter is active when the gate input of the next lower order counter is at high logic state Otherwise the counter is suspended Special Gating The gate input selects the reload source but does not start counting The counter uses the value stored in its internal Hold register when the gate input is high and uses the value stored in its internal Load register when the gate input is low 3 79 NI DAQ User Manual for PC Compatibles
49. supports shunt calibration for the SCXI 1122 module or the SCXI 1121 module with the SCXI 1321 terminal block It also supports shunt calibration for the SCXI 1520 module with the SCXI 1314 terminal block Selects a new channel of a multiplexed module that has previously been set up for a single channel operation using the SCXI_Single Chan Setup function Sets the connection type parameter to a specified type on a given channel or all channels on the SCXI 1520 and SCXI 1540 modules This function also allows programmatic control of external synchronization Sets the specified channel to the assigned filter setting on any SCXI module with programmable filter settings ni com SCXI_Get_Chassis Info SCXI_Get_Module_Info SCXI_Get_State SCXI_Get_Status SCXI_Load_Config SCXI_ModuleID Read National Instruments Corporation 3 109 Chapter 3 Software Overview Returns chassis configuration information Returns configuration information for the assigned SCXI chassis slot number Gets the state of a single channel or an entire port on any digital or relay module Reads the data in the status register on the specified module You can use this function with the SCXI 1160 or SCXI 1122 to determine if the relays have finished switching with the SCXI 1124 to determine if the DACs have settled with the SCXI 1126 to determine if the module has settled after changing any of its programmable functions ranges filter
50. the counter output changes state on the next source edge after reaching TC In addition you can configure the counters for positive logic output or negative inverted logic output Figure 3 27 shows examples of the four types of output signals generated NI DAQ User Manual for PC Compatibles 3 80 ni com Chapter 3 Software Overview Timebase Starting Signal TC Toggle Output TC Pulse Output i 1 gt units timebase period 1 DPDAADIAII a 1 l i Positive Negative Positive F i 4 1 i Negative 1 fi i I i i i i 0 lt sync period lt 1 1 Figure 3 27 Counter Timing and Output Types Figure 3 27 represents a counter generating a delayed pulse see CTR_Pulse in the function reference and demonstrates the four forms the output pulse can take given the four different types of output signals supported The TC toggled positive logic output looks like what is expected when generating a pulse For most of the Counter Timer functions TC toggled output is the preferred output configuration however the other signal types are also available The starting signal shown in Figure 3 27 represents either a software starting of the counter for the no gating case or some sort of signal at the GATE input The signal is either a rising edge gate or a high level gate If the signal is a low level or falling edge gate the starting signal simply
51. under Details select ComponentWorks ActiveX Controls and ComponentWorks DAQ Borland Delphi Examples These examples will be installed in the Examples Visual Basic and Examples Borland Delphi directories respectively under your NI DAQ directory NI DAQ User Manual for PC Compatibles 2 10 ni com Software Overview This chapter describes the function classes in NI DAQ and briefly describes each function NI DAQ functions are grouped according to the following classes e Initialization and general configuration Software calibration and device specific e Event message e Analog input function group One shot analog input e Single channel analog input Data acquisition e High level data acquisition e Low level data acquisition e Low level double buffered data acquisition e Analog output function group One shot analog output Waveform generation e High level waveform generation e Low level waveform generation e Digital I O function group Digital I O Group digital I O e Double buffered digital I O Change Notification Filtering e Counter Timer function group Counter timer Interval counter timer General purpose counter timer National Instruments Corporation 3 1 NI DAQ User Manual for PC Compatibles Chapter 3 Software Overview e RTSI bus trigger e SCXI e Transducer conversion Initialization and General Configuration Functions Use these general functio
52. unscaled data is sufficient or when extra time taken by AI_VRead to scale the data is National Instruments Corporation 3 17 NI DAQ User Manual for PC Compatibles Chapter 3 Software Overview detrimental to your applications Use AI_VScale to convert the binary values to voltages at a later time if you want See Figure 3 1 for the function flow typical of single point data acquisition Also refer to the NJ DAQ Examples Online Help file nidagex h1p to find a related example When using SCXI as a front end for analog input to the DAQCard 700 analog input Lab and 1200 devices MIO and AI device or LPM devices it is not advisable to use the AI_VRead function because that function does not take into account the gain of the SCXI module when scaling the data Use the AI_Read function to obtain the unscaled data then call the SCXI_Scale function using both the SCXI module gain and the DAQ device gain Change analog input default configuration AI_Configure Add AMUX 64T configuration AI_Mux Config Binary reading Retrieve an analog Retrieve an analog reading in terms of a reading in terms of binary value voltage eae yoe AI Read AI_VRead Yes Another reading Figure 3 1 Single Point Analog Reading with Onboard Conversion Timing NI DAQ User Manual for PC Compatibles 3 18 ni com Chapter 3 Software Overview When accurate sample timing is important you can use ex
53. viii ni com About This Manual The NI DAQ User Manual for PC Compatibles is for users of the NI DAQ software for PC compatibles version 6 9 NI DAQ software is a powerful application programming interface API between your data acquisition DAQ application and the National Instruments DAQ devices Source code for several example applications is included in this manual How to Use the NI DAQ Documentation Set Begin by reading the NI DAQ release notes and this manual Chapter 1 Introduction to NI DAQ contains a flowchart that illustrates how to set up your DAQ system using either NI DAQ or other National Instruments application software When you are familiar with the material in this manual you can begin to use the NI DAQ Function Reference Online Help file Nidaqpc h1p the Windows help file that contains detailed descriptions of the NI DAQ functions Other documentation includes the DAQ Hardware Overview Guide and the DAQ provider help contained in Measurement amp Automation Explorer For detailed hardware information refer to the user manual included with each device Conventions Used in This Manual 3 1102 B C modules 12 bit device The following conventions are used in this manual The symbol leads you through nested menu items and dialog box options to a final action The sequence File Page Setup Options directs you to pull down the File menu select the Page Setup item and select Options fro
54. waveform generation 3 50 to 3 51 data acquisition application tips 3 24 groups of ports 3 55 interval counter timer operation 3 92 reference voltages for waveform generation tables 3 50 Lab_ISCAN_Check function 3 22 Lab_ISCAN_Op function 3 20 Lab_ISCAN_ Start function 3 22 Lab_ISCAN_to_Disk function 3 20 languages supported by NI DAQ 1 7 NI DAQ User Manual for PC Compatibles 1 10 libraries NI DAQ 2 1 low level data acquisition functions 3 21 to 3 23 application tips See data acquisition application tips DAQ Check 3 21 DAQ Clear 3 21 DAQ Config 3 21 DAQ Monitor 3 21 DAQ Rate 3 22 DAQ Set_clock 3 22 DAQ Start 3 22 DAQ StopTrigger_Config 3 22 DAQ_VScale 3 22 Lab_ISCAN_Check 3 22 Lab_ISCAN_Start 3 22 SCAN_Demux 3 22 SCAN_Sequence_Demux 3 22 to 3 23 3 33 SCAN_Sequence_Retrieve 3 23 3 33 SCAN_Sequence_Setup 3 23 3 33 SCAN_Setup 3 23 SCAN_ Start 3 23 low level double buffered data acquisition functions 3 23 to 3 24 application tips See data acquisition application tips DAQ_DB_ Config 3 23 4 10 DAQ_DB_HalfReady 3 24 4 12 DAQ_DB _ Transfer 3 24 4 11 low level waveform generation functions 3 39 to 3 41 WFM_Chan_Control 3 39 3 52 WFM_Check 3 39 3 52 WEM_ClockRate 3 39 WEFM_DB_ Config 3 40 WFM_DB_HalfReady 3 40 WFM_DB _ Transfer 3 40 WFM_Group_Control 3 40 WFM_Group_Setup 3 40 WFM_Load 3 40 ni com WFM_ Rate 3 40 WFM_ Scale 3 41 WFM_ Set_Clock 3 41 LPM dev
55. you have time constraints limited in house technical resources or other dilemmas you may prefer to employ consulting or system integration services You can rely on the expertise available through our worldwide network of Alliance Program members To find out more about our Alliance system integration solutions visit the System Integration section of ni com National Instruments Corporation A 1 NI DAQ User Manual for PC Compatibles Appendix A Technical Support Resources Worldwide Support National Instruments has offices located around the world to help address your support needs You can access our branch office Web sites from the Worldwide Offices section of ni com Branch office web sites provide up to date contact information support phone numbers e mail addresses and current events If you have searched the technical support resources on our Web site and still cannot find the answers you need contact your local office or National Instruments corporate Phone numbers for our worldwide offices are listed at the front of this manual NI DAQ User Manual for PC Compatibles A 2 ni com Glossary Prefix Meaning Value u micro 10 m milli 10 k kilo 103 M mega 10 Symbols B coefficient d coefficient degree minus Q ohm percent plus plus or minus e strain a temperature coefficient at T 0 C A D analog to digital AC alternating current Nation
56. 1 to 0 002 C S 50 to 250 C 0 02 C 250 to 1 200 C 0 01 C 1 200 to 1 664 5 C 0 0002 C 1 664 5 to 1 768 1 C 0 002 C T 200 to 0 C 0 02 to 0 04 C 0 to 400 C 0 03 C National Instruments Corporation 5 11 NI DAQ User Manual for PC Compatibles Technical Support Resources Web Support National Instruments Web support is your first stop for help in solving installation configuration and application problems and questions Online problem solving and diagnostic resources include frequently asked questions knowledge bases product specific troubleshooting wizards manuals drivers software updates and more Web support is available through the Technical Support section of ni com NI Developer Zone The NI Developer Zone at zone ni com is the essential resource for building measurement and automation systems At the NI Developer Zone you can easily access the latest example programs system configurators tutorials technical news as well as a community of developers ready to share their own techniques Customer Education National Instruments provides a number of alternatives to satisfy your training needs from self paced tutorials videos and interactive CDs to instructor led hands on courses at locations around the world Visit the Customer Education section of ni com for online course schedules syllabi training centers and class registration System Integration If
57. 10 SCXI_Set_Gain 3 111 SCXI_Set_Input_Mode 3 111 SCXI_Set_State 3 111 SCXI_Set_Threshold 3 111 SCXI_Single_Chan_Setup 3 111 SCXI_Track_Hold_Control 3 111 SCXI_Track_Hold_Setup 3 111 SCXI_Calibrate function 3 4 3 107 to 3 108 Select_Signal function 3 4 3 102 Set_DAQ_ Device_Info function 3 3 setting up DAQ systems See device configuration installation NI DAQ User Manual for PC Compatibles Index simultaneous counter operations figure 3 85 single buffered versus double buffered data 4 1 to 4 2 single channel analog input functions 3 16 to 3 19 AI_Change_Parameter 3 16 AI_Check 3 16 AL _ Clear 3 16 AI_Configure 3 16 AI_Mux_Config 3 17 AI_Read 3 17 AI_Read_Scan 3 17 AI_Read_VScan 3 17 AI_Setup 3 17 AI_VRead 3 17 AI_VScale 3 17 application tips 3 17 to 3 19 software calibration and device specific functions 3 3 to 3 4 AO_ Calibrate 3 3 Calibrate_1200 3 3 to 3 4 Calibrate_DSA 3 4 Calibrate_E_Series 3 4 Calibrate_TIO 3 4 Configure_HW_Analog_Trigger 3 4 LPM16_Calibrate 3 4 MIO_Config 3 4 SCXI_Cal_Constants 3 107 SCXI_Calibrate 3 4 3 107 to 3 108 SCXI_Calibrate_Setup 3 108 Select_Signal 3 4 3 102 square wave generation functions 3 84 STOPTRIGI signal table 3 105 STOPTRIG2 signal table 3 105 Strain_Buf_Convert function 5 4 to 5 6 Strain_Convert function definition 5 1 purpose and use 5 4 to 5 6 string passing in Windows applications Microsoft Visual Basic 2 6 Microsoft
58. 11 to 3 13 Analog Trigger Event control 3 9 to 3 11 General DAQ Event controls 3 7 to 3 9 General DAQ Event example 3 13 to 3 15 multiple controls 3 13 using multiple controls 3 13 NI DAQ installation See installation NI DAQ libraries for Windows 2 1 NI DAQ software features 1 1 to 1 2 hardware support tables 1 4 to 1 6 language support 1 7 overview 1 3 nidaq32 dll note 2 1 NI TIO based devices See clocks or time counters for NI TIO devices no handshaking mode 3 54 NI DAQ User Manual for PC Compatibles Index 0 one shot analog input functions 3 16 to 3 19 AI_Change_Parameter 3 16 AIL Check 3 16 AI_Clear 3 16 AI_Configure 3 16 AI_Mux_Config 3 17 AIL Read 3 17 AI_Read_Scan 3 17 AI_Read_VScan 3 17 AI_Setup 3 17 AI_VRead 3 17 AI_VScale 3 17 application tips 3 17 to 3 19 one shot analog output functions AO_Change_Parameter 3 35 AO_Configure 3 35 AO_Update 3 35 AO_VScale 3 36 AO_VWrite 3 36 AO_ Write 3 36 application tips 3 36 to 3 38 OUTO signal table 3 104 OUT 1 signal table 3 104 OUT2 signal table 3 104 P Parallel mode applications SCXI modules 3 120 to 3 124 parameter passing in Windows applications Microsoft Visual Basic 2 6 Microsoft Visual C 2 3 pattern generation I O with DIO 32F 653X PCI 6115 and PCI 6120 devices 3 74 to 3 75 PC DIO 24 groups of ports 3 55 PC DIO 96 groups of ports 3 55 NI DAQ User Manual for PC Compatibles PCI 4451 device
59. 1143 SCXI 1520 SCXI 1530 SCXI 1531 or SCXI 1540 module operating in multiplexed mode Set up the chassis for a single channel analog input operation on a specified channel on a specified module SCXI_Single Chan Setup If the desired module has programmable gain and the current module gain setting is not desirable change to the desired gain SCXI_Set_Gain y Acquire data from the y desired channel on the Single Analog Input module using the AI Single Channel Data Acquisition functions or the DAQ functions If desired change the selected channel on AA the module se Change Chan Have you acquired all the data you need from this module No Figure 3 42 Single Channel or Software Scanning Operation in Multiplexed Mode The sCxI_Single_Chan_Setup function selects the given channel to appear at the module output If the given module is not directly cabled to the DAQ device the function sends the module output on the SCXIbus and then configures the module that is cabled to the DAQ device to send the signal present on the SCXIbus to the DAQ device NI DAQ User Manual for PC Compatibles 3 114 ni com Chapter 3 Software Overview The SCXI_Set_Gain function changes the gain or range of the SCXI 1100 SCXI 1102 B C VXI SC 1102 B C SCXI 1122 SCXI 1125 SCXI 1126 SCXI 1141 SCXI 1142 SCXI 1143 SCXI 1520 SCXI 1530 SCXI 1531 or SCXI 1540 module The module m
60. 25E groups of ports 3 55 6115 and 6120 devices See PCI 6115 and PCI 6120 devices 622XI devices counter usage 3 50 FIFO lag effect 3 51 to 3 52 652X devices digital change detection applications 3 60 digital change notification applications 3 60 653X devices digital change detection applications 3 61 to 3 62 groups of ports 3 55 to 3 56 pattern generation 3 74 to 3 75 RTSI connections 3 105 to 3 106 660X devices RTSI connections 3 103 671X devices counter usage 3 50 FIFO lag effect 3 51 to 3 52 RTSI connections 3 103 A ACK 1 signal 653X RTSI connections table 3 105 DIO 32F RTSI connections table 3 104 ACK2 signal 653X RTSI connections table 3 105 DIO 32F RTSI connections table 3 104 ActiveX controls for Visual Basic 3 6 to 3 7 National Instruments Corporation AI device terminology table xv xvii AI_Change_Parameter function 3 16 AI_Check function 3 16 AI_Clear function 3 16 AI_Configure function 3 16 AI_Mux_Config function 3 17 AI_Read function 3 17 AI_Read_Scan function 3 17 AI_Read_VScan function 3 17 AI_Setup function 3 17 AI_VRead function 3 17 AI_VScale function 3 17 Align _DMA_ Buffer function 3 2 Am9513 based devices gating modes 3 79 timebases 3 78 AMUX 64T external multiplexer support 3 25 Analog Alarm Event control 3 11 to 3 13 properties table 3 11 setting program flow 3 12 to 3 13 setting properties 3 12 analog input application tips See data acquisit
61. 3 23 4 10 DAQ StopTrigger_Config 3 22 DIG_Block_PG_Config 3 58 DIG_Change_Message_Config 3 60 DIG_DB_Config 3 59 4 10 DIG_Filter_Config 3 60 DIG_Grp_Config 3 58 DIG_Line_Config 3 57 DIG_Prt_Config 3 58 DIG_SCAN_ Setup 3 59 DIG_Trigger_Config 3 59 GPCTR_Change_Parameter 3 93 4 10 MIO_Config 3 4 SCXI_Configure_Connection 3 108 SCXI_Configure_Filter 3 108 SCXI_Load_Config 3 109 SCXI_MuxCtr_Setup 3 110 SCXI_SCAN_ Setup 3 110 SCXI_Set_Config 3 110 SCXI_Set_Excitation 3 110 SCXI_Set_Gain 3 111 SCXI_Set_Input_Mode 3 111 SCXI_Set_State 3 111 SCXI_Set_Threshold 3 111 SCXI_Single_Chan_Setup 3 111 SCXI_Track_Hold_Setup 3 111 Timeout_Config 3 3 WFM_DB_Config 3 40 4 10 WFM_Group_Setup 3 40 Configure_HW_Analog_ Trigger function 3 4 conventions used in manual xi xvii counter timer application tips 3 82 to 3 91 See also counter timer functions counter timer operation concatenated event counting 3 88 to 3 89 event counting 3 86 to 3 89 National Instruments Corporation l 3 Index event counting flow chart figure 3 82 event counting functions 3 82 frequency measurement 3 87 to 3 88 general purpose counter timer functions 3 94 to 3 95 interval counter timer functions 3 92 period and continuous pulse width measurement 3 89 to 3 91 pulse generation flow chart figure 3 83 pulse width measurement 3 86 to 3 87 pulse generation functions 3 83 to 3 84 simultaneous counter operations fi
62. 5 WFM Group Control with operation START to start the waveform generation in the background and return to your application after the waveform generation has begun The next step in Figure 3 15 shows how the call to WFM_Check WFM_Check retrieves the current status of the waveform generation Your application uses this information to determine if the generation is complete or should be stopped The final step is to call WFM_Group_Control operation CLEAR The CLEAR operation performs all of the necessary cleanup work after a waveform generation Additionally CLEAR halts any ongoing waveform generation NI DAQ User Manual for PC Compatibles 3 42 ni com Chapter 3 Software Overview y Convert floating point voltages to binary values WFM_Scale Assign channels to the waveform generation group Load waveform buffer specify iterations and start waveform WFM_Group_Setup Load waveform buffer and specify iterations If iterations gt 0 the waveform generation is complete Convert output rate to timebase and interval Iterations gt 0 Yes WFM_ Rate No Set the update rate WFM_ClockRate or WFM Set Clock Start background waveform generation WFM_Group_ Control operation START SS WFM_Check Any more data to output No Clear waveform WFM_Group_Control operation CLEAR Figure 3 15 Basic Wa
63. ANY WARRANTY OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE CUSTOMER S RIGHT TO RECOVER DAMAGES CAUSED BY FAULT OR NEGLIGENCE ON THE PART OF NATIONAL INSTRUMENTS SHALL BE LIMITED TO THE AMOUNT THERETOFORE PAID BY THE CUSTOMER NATIONAL INSTRUMENTS WILL NOT BE LIABLE FOR DAMAGES RESULTING FROM LOSS OF DATA PROFITS USE OF PRODUCTS OR INCIDENTAL OR CONSEQUENTIAL DAMAGES EVEN IF ADVISED OF THE POSSIBILITY THEREOF This limitation of the liability of National Instruments will apply regardless of the form of action whether in contract or tort including negligence Any action against National Instruments must be brought within one year after the cause of action accrues National Instruments shall not be liable for any delay in performance due to causes beyond its reasonable control The warranty provided herein does not cover damages defects malfunctions or service failures caused by owner s failure to follow the National Instruments installation operation or maintenance instructions owner s modification of the product owner s abuse misuse or negligent acts and power failure or surges fire flood accident actions of third parties or other events outside reasonable control Copyright Under the copyright laws this publication may not be reproduced or transmitted in any form electronic or mechanical including photocopying recording storing in an information retrieval system or translating in whole or in part without the prio
64. AQ Function Reference Online Help file HighAlarmLevel Single voltage LowAlarmLevel Single voltage HighDeadbandWidth Single voltage LowDeadbandWidth Single voltage Index N A Tag N A Enabled 0 False default 1 True The Analog Alarm Event requires that you set the asynchronous data acquisition operation to use interrupts For more information on Analog Alarm Events refer to the description for the Config Alarm _Deadband function in the NJ DAQ Function Reference Online Help file National Instruments Corporation 3 11 NI DAQ User Manual for PC Compatibles Chapter 3 Software Overview Each of these properties should be set as follows AnalogAlarmEventn property name property value For instance to set the ChanStr property to Analog Input channel 0 for Analog Alarm Event 1 AnalogAlarmEvent1 ChanStr AIO Set up your program flow like this 1 Set the properties of the Analog Alarm Event control Next configure the acquisition or generation operations using the appropriate NI DAQ functions 2 Set the Enabled property of the Analog Alarm Event control to 1 True 3 Invoke the AnalogAlarmEventn Refresh method to set the Analog Alarm Event in the NI DAQ driver Each subsequent invocation of AnalogAlarmEventn Refresh deletes the old Analog Alarm Event and sets a new one with the current set of properties 4 Start an asynchronous data acquisition operation Call any o
65. Chapter 3 Software Overview Counter operation starts and stops relative to the selected timebase When a counter is configured for no gating the counter starts at the first timebase source edge rising or falling depending on the selection after the software configures the counter When a counter is configured for gating modes gate signals take effect at the next timebase source edge For example if a counter is configured to count rising edges and to use the falling edge gating mode the counter starts counting on the next rising edge after it receives a high to low edge on its GATE input Thus some time is spent synchronizing the GATE input with the timebase source This synchronization time creates a time lapse uncertainty from 0 to timebase period between the signal application at the GATE input and the start of the counter operation The counter generates timing signals at its OUT output If the counter is not operating you can set its output to one of three states high impedance state low logic state or high logic state The counters generate two types of output signals during counter operation TC pulse output and TC toggled output A counter reaches TC when it counts up to 65 535 or down to 0 and rolls over In many counter applications the counter reloads from an internal register when it reaches TC In TC pulse output mode the counter generates a pulse during the cycle in which it reaches TC In TC toggled output mode
66. Connections eee eeeeeeeseeseeeseeseeeseceecseecsesesesseseaeenees 3 104 DIO 32F RTSI Connections iaoee essetis aena asis 3 104 653X RTSI Comnecttons i niniin ap a a 3 105 RTSI Bus Application Tips ssesesseesssesssessesrssesrsresresrsrestesrsresesresresesresrsresresret 3 106 SCXL PUNCt ons ivi ss 35 5 naan ra aa apoia aitase 3 107 SCXI Application TIPS eisista erin E e eaa aa E ae 3 112 Building Analog Input Applications in Multiplexed Mode 3 113 Building Analog Input Applications in Parallel Mode 00 3 120 SCXI Data Acquisition Rates 0 eee eee eeeceeeeseteseeseeeeeeeeseeeaeens 3 124 Analog Output Applications eee ceceseeseeeeceeeeseeseeeseeaesnsecsesseeeseeseeeaees 3 126 Digital A pplications s cc sesissescescssssescseesisescgeveadeabs cossagsebessdsadeess A aa 3 127 National Instruments Corporation vii NI DAQ User Manual for PC Compatibles Contents Chapter 4 NI DAQ Double Buffering COV ET VIE AEEA E TEE E eee tate ae eek ei tacos Mae oa SS 4 1 Single Buffered Versus Double Buffered Data s sseeseseessseseseessesreresrsresresrsreserersreerse 4 1 Double Buffered Input Operations sseessessssesseessseerssrsresrsresrestsresrsresrestsresrsresresreees 4 2 PotentralcSetbacks vis dsceoeteedoetedes a rea E e i i aae 4 4 Double Buffered Output Operations ssessesesesessesesssrestsrtsrestsrestrresreresrentesrsresresentees 4 6 Potential Setbacks eccccssiscccseesciserececess s
67. DAQ NI DAQ User Manual for PC Compatibles Version 6 9 Data Acquisition Software for the PC Wy NATIONAL October 2000 Edition p INSTRUMENTS Part Number 321644H 01 Worldwide Technical Support and Product Information ni com National Instruments Corporate Headquarters 11500 North Mopac Expressway Austin Texas 78759 3504 USA Tel 512 794 0100 Worldwide Offices Australia 03 9879 5166 Austria 0662 45 79 90 0 Belgium 02 757 00 20 Brazil 011 284 5011 Canada Calgary 403 274 9391 Canada Ontario 905 785 0085 Canada Qu bec 514 694 8521 China 0755 3904939 Denmark 45 76 26 00 Finland 09 725 725 11 France 01 48 14 24 24 Germany 089 741 31 30 Greece 30 1 42 96 427 Hong Kong 2645 3186 India 91805275406 Israel 03 6120092 Italy 02 413091 Japan 03 5472 2970 Korea 02 596 7456 Mexico D F 5 280 7625 Mexico Monterrey 8 357 7695 Netherlands 0348 433466 New Zealand 09 914 0488 Norway 32 27 73 00 Poland 0 22 528 94 06 Portugal 351 1 726 9011 Singapore 2265886 Spain 91 640 0085 Sweden 08 587 895 00 Switzerland 056 200 51 51 Taiwan 02 2528 7227 United Kingdom 01635 523545 For further support information see the Technical Support Resources appendix To comment on the documentation send e mail to techpubs ni com Copyright 1991 2000 National Instruments Corporation All rights reserved Important Information Warranty The media on which you receive National Instruments software are warranted not to
68. DI Digital Input examples DO Digital Output examples CTR Counter timer examples SCXI SCXI examples CALIB Calibration examples National Instruments Corporation 2 9 NI DAQ User Manual for PC Compatibles Chapter 2 Fundamentals of Building Windows Applications The project files have the same file name not including extension as the source code files The following types are installed e LabWindows CVI prj project file c source file e Visual C mak generic make file c source file e Visual Basic vbp project file for Visual Basic 4 0 32 bit or later fxm form module e Borland C bat Batchfile c source file For more information about each example how to compile examples and details on the NI DAQ Example Utility functions please refer to the NI DAQ Examples Online Help file To open this file go to Start Programs National Instruments DAQ NI DAQ Examples Help You will have this file only if you installed support for LabWindows CVI Visual C Visual Basic or Borland C examples In addition to examples using the NI DAQ API you can install and use examples using the ComponentWorks DAQ controls Run the NI DAQ Setup Utility Start Programs National Instruments DAQ NI DAQ Setup and choose either of the following e Microsoft Visual Basic under Details select ComponentWorks ActiveX Controls and ComponentWorks DAQ Visual Basic Examples e Borland Delphi
69. E HEREAFTER COLLECTIVELY TERMED SYSTEM FAILURES ANY APPLICATION WHERE A SYSTEM FAILURE WOULD CREATE A RISK OF HARM TO PROPERTY OR PERSONS INCLUDING THE RISK OF BODILY INJURY AND DEATH SHOULD NOT BE RELIANT SOLELY UPON ONE FORM OF ELECTRONIC SYSTEM DUE TO THE RISK OF SYSTEM FAILURE TO AVOID DAMAGE INJURY OR DEATH THE USER OR APPLICATION DESIGNER MUST TAKE REASONABLY PRUDENT STEPS TO PROTECT AGAINST SYSTEM FAILURES INCLUDING BUT NOT LIMITED TO BACK UP OR SHUT DOWN MECHANISMS BECAUSE EACH END USER SYSTEM IS CUSTOMIZED AND DIFFERS FROM NATIONAL INSTRUMENTS TESTING PLATFORMS AND BECAUSE A USER OR APPLICATION DESIGNER MAY USE NATIONAL INSTRUMENTS PRODUCTS IN COMBINATION WITH OTHER PRODUCTS IN A MANNER NOT EVALUATED OR CONTEMPLATED BY NATIONAL INSTRUMENTS THE USER OR APPLICATION DESIGNER IS ULTIMATELY RESPONSIBLE FOR VERIFYING AND VALIDATING THE SUITABILITY OF NATIONAL INSTRUMENTS PRODUCTS WHENEVER NATIONAL INSTRUMENTS PRODUCTS ARE INCORPORATED IN A SYSTEM OR APPLICATION INCLUDING WITHOUT LIMITATION THE APPROPRIATE DESIGN PROCESS AND SAFETY LEVEL OF SUCH SYSTEM OR APPLICATION Contents About This Manual How to Use the NI DAQ Documentation Set ccc cccccceesseeceeseeeeeseeeeseneeessneeesseeeens xi Conventions Used in This Manual cccccccsscccssscceseeesseeesseeessneeeseseeesseeesseeessaeens xi MIO and AI Device Terminology sssseessssessseessersrrsrerreresrsresresrsresesresreersrestee XV Chapter 1 Introduc
70. I DAQ Function Reference Online Help file for more information on using the NI DAQ functions in Visual Basic for Windows NI DAQ User Manual for PC Compatibles 2 4 ni com Chapter 2 Fundamentals of Building Windows Applications Example Programs You can find some example programs and project files in Examples VBasic directory under your NI DAQ directory To load an example program use one of the Visual Basic project files with the vbp extension These are Visual Basic 4 0 projects which you can open only with Visual Basic 4 0 or later To load an example project with Visual Basic 4 0 or later select the menu option File Open Project then select the vbp file of your choice Refer to the NI DAQ Examples Help Start Programs National Instruments DAQ NI DAQ Examples Help for additional information regarding NI DAQ examples Special Considerations Buffer Allocation Visual Basic 4 0 is quite restrictive when allocating memory You allocate memory by declaring an array of the data type with which you want to work Visual Basic uses dynamic memory allocation so you can redimension an array to a variable size during run time However arrays are restricted to being less than 64 KB in total size this translates to about 32 767 16 bit integers 16 384 32 bit long integers or 8 191 doubles To break the 64 KB buffer size barrier you can use the Windows API functions GlobalAlloc to allocate buffers larger than 64 KB Aft
71. O 48XDC DAQCard 6023E DAQCard AO 2DC DAQCard 6024E DAQCard DIO 24 DAQCard 6062E National Instruments Corporation 1 5 NI DAQ User Manual for PC Compatibles Introduction to NI DAQ Table 1 5 NI DAQ Version 6 9 External Device Support for SCX and USB Devices SCXI USB PXI 1010 SCXI 1120D SCXI 1200 DAQPad 6507 PXI 1011 SCXI 1121 SCXI 1520 DAQPad 6508 SCXI 1000 SCXI 1122 SCXI 1530 DAQPad 6020E SCXI 1000DC SCXI 1124 SCXI 1531 DAQPad 6052E for USB SCXI 1001 SCXI 1125 SCXI 1540 SCXI 1010 SCXI 1126 SCXI 2000 SCXI 1011 SCXI 1140 SCXI 2400 SCXI 1100 SCXI 1141 SCXI 1122 SCXI 1101 SCXI 1142 VXI SC 1000 SCXI 1102 SCXI 1143 VXI SC 1102 SCXI 1102B SCXI 1160 VXI SC 1102B SCXI 1102C SCXI 1161 VXI SC 1102C SCXI 1104 SCXI 1162 VXI SC 1150 SCXI 1104C SCXI 1162HV SCXI 1112 SCXI 1163 SCXI 1120 SCXI 1163R This device works with NEC PC 9800 computers only when used with remote SCXI 2 These devices do not work with NEC PC 9800 computers Table 1 6 NI DAQ Version 6 9 External Device Support for Parallel Port 1394 and Other Devices Parallel Port 1394 Other Devices DAQPad 1200 DAQPad MIO 16XE 50 DAQPad 6052E for 1394 DAQPad 6070E AMUX 64T SC 2040 SC 2042 RTD SC 2043 SG SC 2345 NI 6224 for Ethernet Throughout this manual many of the devices are grouped into categories that are similar in functionality The categories are often used in the text to
72. Out_Line 3 57 DIG_Out_Prt 3 58 DIG_Prt_Config 3 58 DIG_Prt_Status 3 58 double buffered digital I O functions 3 59 DIG_DB_Config 3 59 4 10 DIG_DB_HalfReady 3 59 4 12 DIG_DB_ Transfer 3 59 4 11 group digital I O functions 3 58 to 3 59 DIG_Block_Check 3 58 DIG_Block_Clear 3 58 DIG_Block_In 3 58 DIG_Block_Out 3 58 DIG_Block_PG_Config 3 58 DIG_Grp_Config 3 58 DIG_Grp_Mode 3 58 DIG_Grp_Status 3 58 NI DAQ User Manual for PC Compatibles l 6 DIG_In_Grp 3 58 DIG_Out_Grp 3 59 DIG_SCAN_Setup 3 59 DIG_Trigger_Config 3 59 groups of ports DIO 24 6025E AT MIO 16DE 10 DIO 96 and Lab and 1200 series 3 55 DIO 32F and 653X 3 55 to 3 56 overview 3 52 to 3 55 DIG_Line_Config function 3 57 DIG_Out_Grp function 3 59 DIG_Out_Line function 3 57 DIG_Out_Prt function 3 58 DIG_Prt_Config function 3 58 DIG_Prt_Status function 3 58 DIG_SCAN_Setup function 3 59 DIG_Trigger_Config function 3 59 DIO 24 groups of ports 3 55 DIO 32F groups of ports 3 55 to 3 56 pattern generation 3 74 to 3 75 RTSI bus connections 3 104 to 3 105 DIO 96 groups of ports 3 55 documentation conventions used in manual xi xvii how to use NI DAQ manual set xi double buffered data acquisition 4 1 to 4 12 application tips 3 31 to 3 32 input operations 4 2 to 4 5 problem situations 4 4 to 4 5 output operations 4 6 to 4 9 problem situations 4 7 to 4 9 overview 4 1 single buffered versus double buffered data 4 1 to 4 2 dou
73. Output data to port DIG In Prt DIG Out Prt No Yes Figure 3 20 Basic Port Input or Output Application with Handshaking Y DIG Prt_Config t Input data from port z Output data to port DIG In Prt DIG Out _Prt No Yes Figure 3 21 Basic Port Input or Output Application without Handshaking NI DAQ User Manual for PC Compatibles 3 64 ni com Chapter 3 Software Overview The first step is to call DIG_Prt_Config with which you configure the individual digital ports for input or output and enable handshaking If handshaking is disabled do not check the port status step 2 of Figure 3 21 If handshaking is enabled call DIG_PRT_ Status to determine if an output port is ready to output a new data point or if an input port has latched new data The third step is to input or output the data point Call DIG_In_Prt toread data from an input port Call DIG_Out_Prt to write data to an output port The final step is to loop back if more data is to be input or output These four steps form the basis of a simple digital port I O application Digital Line 1 0 Applications Digital line I O applications are similar to digital port I O applications except that digital line I O applications input or output data on a bit by bit basis rather than by port The digital line I O can only transfer data in no handshaking mode National Instruments Corporation 3 65 NI DAQ User Manual for PC Compat
74. Q device Sets the module channel enables the module output and routes the module output on the SCXIbus if necessary Resolves any contention on the SCXIbus by disabling the output of any module that was previously driving the SCXIbus You also can use this function to set up to read the temperature sensor on a terminal block connected to the front connector of the module Controls the track and hold modules track hold state that you set up for a single channel operation Establishes the track hold behavior of a track and hold module and sets up the module for either a single channel or an interval scanning operation NI DAQ User Manual for PC Compatibles Chapter 3 Software Overview SCXI Application Tips There are three categories of SCXI applications analog input applications analog output applications and digital applications Figure 3 41 shows the basic structure of an SCXI application Load SCXI configuration that was entered in the Measurement amp Automation Explorer and initialize software defaults SCXI_Load_Config Reset the chassis and modules to their default hardware settings SCXI_Reset Y Y Y Analog Input Operations Analog Output Operations Digital Operations Yes Reset the chassis and modules to their default hardware settings SCXI_Reset Figure 3 41 General SCXIbus Application The figures in the following sections show the d
75. SI_Conn calls RTSI_Conn RTSI_DisConn Disconnect all device and clock signals from RTSI bus RTSI_ Clear Disconnect device signal from RTSI bus Disconnect clock signal from RTSI bus RTSI_ Clock Figure 3 40 Basic RTSI Application Calls NI DAQ User Manual for PC Compatibles 3 106 ni com Chapter 3 Software Overview Call RTSI_Clock RTSI_Conn to connect the signals Each completed signal path requires RTSI_Conn calls The first call specifies the device signal to transmit onto a RTSI bus trigger line The second call specifies the device signal that receives a RTSI bus trigger line After the signals are connected you are ready to do the actual work of your application After you finish with the RTSI bus disconnect the device from the bus To do this call RTSI_DisConn RTSI Clock for each connection made Alternatively call RTSI_Clear to sever all connections from your device to the RTSI bus SCXI Functions Refer to the NI DAQ Function Reference Online Help file to determine which functions your device supports SCXI_AO Write SCXI_Cal_Constants SCXI_Calibrate National Instruments Corporation 3 107 Sets the DAC channel on the SCXI 1124 module to the specified voltage or current output value You also can use this function to write a binary value directly to the DAC channel or to translate a voltage or current value to the corresponding binary value Ca
76. TSI_Conn Connects a device signal to the specified RTSI bus trigger line RTSI_DisConn Disconnects a device signal from the specified RTSI bus trigger line Select_Signal Connects or disconnects a device signal to a RTSI bus trigger line Refer to the NI DAQ Function Reference Online Help file to determine if your device supports RTSI The RTSI bus is implemented via a 34 pin ribbon cable connector on the AT NEC PCI E Series PCI DSA and 671X devices The RTSI bus is implemented on VXI DAQ devices using the VXIbus trigger lines On PXI DAQ and DSA devices the RTSI bus is implemented using PXI trigger bus lines On 1394 E Series DAQ devices the RTSI bus is implemented with a 15 pin mini DSUB connector The RTSI bus has a NI DAQ User Manual for PC Compatibles 3 102 ni com Chapter 3 Software Overview 7 wire trigger bus Each device that works with a RTSI bus interface contains a number of useful signals that can be driven onto or received from the trigger lines Each device is equipped with a switch with which an onboard signal is connected to any one of the RTSI bus trigger lines through software control By programming one device to drive a particular trigger line and another device to receive from the same trigger line you can hardware connect the two devices Use the RTSI Bus Trigger functions described in this chapter for this type of programmable signal interconnection between devices Through the RTSI bus you can trig
77. True 3 Invoke the AnalogTriggerEventn Refresh method to actually set the Analog Trigger Event in the NI DAQ driver Each subsequent invocation of AnalogTriggerEventn Refresh deletes the old Analog Trigger Event and sets a new one with the current set of properties 4 Start an asynchronous data acquisition operation When the Analog Trigger conditions are met the AnalogTriggerEventn_ Fire procedure is called You can perform the necessary event processing within this procedure such as updating a global count variable or toggling digital I O lines NI DAQ User Manual for PC Compatibles 3 10 ni com Chapter 3 Software Overview The AnalogTriggerEventn_ Fire procedure is prototyped as follows Sub AnalogTriggerEventn Fire DoneFlag As Integer Scans As Long The parameter DoneFlag equals 1 if the acquisition was over when the Analog Trigger Event fired Otherwise it is 0 Scans equals the number of the scan that caused the Analog Trigger Event to fire Analog Alarm Event Use the Analog Alarm Event control to configure and enable an analog trigger See the Event Message Functions section earlier in this chapter for a definition of the analog trigger Table 3 3 lists the properties for the Analog Alarm Event control Table 3 3 Analog Alarm Event Control Properties Property Allowed Property Values Name GeneralDAQEventn default Board l n default Chanstr See Config DAQ Event Message in the NI D
78. Visual C 2 3 NI DAQ User Manual for PC Compatibles 1 14 synchronization of clocks See clocks or time counters for NI TIO devices system integration by National Instruments A 1 T technical support resources A 1 to A 2 Thermistor_Buf_Convert function 5 7 to 5 9 Thermistor_Convert function definition 5 1 purpose and use 5 7 to 5 9 Thermocouple_Buf_Convert function 5 9 to 5 11 Thermocouple_Convert function definition 5 1 purpose and use 5 9 to 5 11 time counters See clocks or time counters for NI TIO devices time lapse measurement 3 87 Timeout_Config function 3 3 transducer conversion functions 5 1 to 5 11 overview 5 1 to 5 2 RTD_Buf_Convert 5 2 to 5 4 RTD_Convert 5 1 5 2 to 5 4 Strain_Buf_Convert 5 4 to 5 6 Strain_Convert 5 1 5 4 to 5 6 Thermistor_Buf_Convert 5 7 to 5 9 Thermistor_Convert 5 1 5 7 to 5 9 Thermocouple_Buf_Convert 5 9 to 5 11 Thermocouple_Convert 5 1 5 9 to 5 11 V Visual Basic See Microsoft Visual Basic for Windows ni com Index W Web support from National Instruments A 1 WFM_Chan_Control function 3 39 3 52 waveform generation application WFM_ Check function 3 39 3 52 tips 3 41 to 3 52 National Instruments Corporation basic applications 3 41 to 3 43 basic waveform generation with pauses 3 44 to 3 46 counter usage 3 50 to 3 51 double buffered applications 3 47 to 3 48 external triggering 3 52 FIFO lag effect 3 51 to 3 52 minimum update interva
79. Writes digital output data to the specified digital group Configures the specified group for port assignment direction input or output and size Enables or disables the trigger mode of buffered digital I O to indicate when to start and stop the data acquisition The double buffered digital I O DIG_DB functions perform double buffered operations during Group Digital I O operations Refer to the NI DAQ Function Reference Online Help file to determine which functions your device supports DIG_DB Config DIG _DB HalfReady DIG DB Transfer National Instruments Corporation 3 59 Enables or disables double buffered digital transfer operations and sets the double buffered options Checks whether the next half buffer of data is available during a double buffered digital block operation You can use DIG DB HalfReady to avoid the possible waiting period that can occur because DIG _DB Transfer waits until the data can be transferred before returning For an input operation DIG DB Transfer waits until NI DAQ can transfer half the data from the buffer being used for double buffered digital block input to another buffer which is passed to the function For an output operation DIG _DB Transfer waits until NI DAQ can transfer the data from the buffer passed to the function to the buffer being used for double buffered digital block output You can execute DIG DB Transfer repeatedly to read or write sequential half buffer
80. a acquisition requires some simple changes to the first and third basic building blocks Configuration and Checking respectively In building block 1 turn on double buffered mode data acquisition through the DAQ DB _ Config call After the double buffered mode is enabled all subsequent data acquisitions are in double buffered mode In building block 3 different checking functions are needed Figure 3 10 shows a simple way to monitor the data acquisition in progress and to retrieve data when they are available For further details on double buffered data acquisition consult Chapter 4 NI DAQ Double Buffering National Instruments Corporation 3 31 NI DAQ User Manual for PC Compatibles Chapter 3 3 NI DAQ User Manual for PC Compatibles Software Overview Check for next half buffer availability DAQ DB HalfReady Next half buffer ready for transfer Retrieve half of the data in Yes the data acquisition buffer DAQ DB Transfer Data acquisition complete Figure 3 10 Double Buffered Data Acquisition Application Building Block 3 Checking Multirate Scanning Use multirate scanning to scan multiple channels at different scan rates and acquire the minimum amount of data necessary for your application This is particularly useful if you are scanning very fast and want to write your data to disk or if you are acquiring large amounts of data and want to keep your buffe
81. ach module You also can use the SCXI_Configure_Filter function for the SCXI 1122 SCXI 1125 SCXI 1126 SCXI 1141 SCXI 1142 and SCXI 1143 SCXI 1530 SCXI 1531 and the SCxI_Set_Input_Mode function for the SCXI 1122 The SCXI_MuxCtr_Setup call synchronizes the module scan list with the DAQ device or SCXI 1200 scan list In most cases especially when using interval scanning it is best to ensure that the number of samples NI DAQ takes in one pass through the module scan list is the same as the number of samples NI DAQ takes in one pass through the DAQ device scan list Please refer to the SCXI_MuxCtr_Setup function description in the NI DAQ Function Reference Online Help file After you have set up the SCXI chassis and modules you can perform more than one channel scanning operation using the SCAN or Lab_ISCAN functions without reconfiguring the SCXI chassis or modules National Instruments Corporation 3 119 NI DAQ User Manual for PC Compatibles Chapter 3 Software Overview When you are using the SCXI 1200 to acquire the data pass channel 0 to the Lab_ISCAN functions the SCXI Slot 0 takes care of all the channel switching Building Analog Input Applications in Parallel Mode When you operate the SCXI 1120 D SCXI 1121 SCXI 1125 SCXI 1126 SCXI 1141 SCXI 1142 and SCXI 1143 modules in parallel mode you need no further SCXI function calls beyond those shown in Figure 3 43 to set up the modules for analog input operations Afte
82. aintains this gain or range setting until you call the function again to change it You can also do any other module specific programming at this point such as SCXI_Configure_ Filter or SCXI_Set_Input_Mode To achieve software scanning select a different channel on the module using the SCXI_Change_Chan function after acquiring data from the channel you want with the AI or DAQ functions If you want a channel on a different module call the SCXI_Single Chan Setup function again to enable the appropriate module outputs and manage the SCXIbus signal routing Figure 3 43 shows the function call sequence of a single channel or software scanning application using a Simultaneous Sample and Hold SSH module in multiplexed mode National Instruments Corporation 3 115 NI DAQ User Manual for PC Compatibles Chapter 3 Software Overview Configure the desired module for a single channel operation SCXI_Track_Hold_ Setup Set up the chassis for a single channel analog input operation on a specified channel y ona specified module SCXI_Single Chan Setup Latch the analog inputs by putting the module into Hold mode SCXI_Track_Hold_Control Acquire data from the desired channel on the module using the AI functions Single Analog Input If desired change the p selected channel on the module If desired change the selected channel on the module SCXI_Change_Chan SCXI_Chang
83. al Instruments Corporation G 1 NI DAQ User Manual for PC Compatibles Glossary ACK ActiveX ActiveX control ADC ADC resolution Al AMD analog trigger API ARB asynchronous background acquisition bandwidth NI DAQ User Manual for PC Compatibles acknowledge A programming system and user interface that lets you work with interactive objects Formerly called OLE a standard software tool that adds additional functionality to any compatible ActiveX container A D converter an electronic device often an integrated circuit that converts an analog voltage to a digital number The resolution of the ADC which is measured in bits An ADC with 16 bits has a higher resolution and thus a higher degree of accuracy than a 12 bit ADC analog input Advanced Micro Devices A trigger that occurs at a user selected point on an incoming analog signal Triggering can be set to occur at a specific level on either an increasing or a decreasing signal positive or negative slope Analog triggering can be implemented either in software or in hardware When implemented in software LabVIEW all data is collected transferred into system memory and analyzed for the trigger condition When analog triggering is implemented in hardware no data is transferred to system memory until the trigger condition has occurred application programming interface pertaining to arbitrary waveform generation NI 54XX devices only 1
84. alue within specified limits a technique used for extending the address range of a device to point into a larger address space personal computer G 8 ni com PCI port posttriggering PPS pretriggering programmed I O pts PXI R RAM remote SCXI REQ resolution ROM RTC National Instruments Corporation G 9 Glossary Peripheral Component Interconnect a digital port consisting of four or eight lines of digital input and or output the technique used on a DAQ board to acquire a programmed number of samples after trigger conditions are met Pulse per second A signal normally produced by a GPS receiver the technique used on a DAQ board to keep a continuous buffer filled with data so that when the trigger conditions are met the sample includes the data leading up to the trigger condition the standard method a CPU uses to access an I O device each byte of data is read or written by the CPU points PCI eXtensions for Instrumentation PXI is an open specification that builds off the CompactPCI specification by adding instrumentation specific features random access memory An SCXI configuration in which a serial port cable is connected to an SCXI 2000 chassis or an SCXI 100X chassis with an SCXI 2400 remote communications module Multiple Remote SCXI units can be connected to one serial port in a PC by using RS 485 You can use either an RS 485 interface card in your PC or an RS 485 converter on t
85. an output operation latched from the digital lines Instead group operations are done from a buffer In the case of digital output operations values are written to a buffer and latched onto the digital lines when the appropriate edge from a clock signal is detected For digital input operations values are latched from the digital lines to the buffer when the appropriate edge of the clock signal is detected Either a rising edge or a falling edge of the clock signal can be specified for latching the values The clock source can be a timing signal used internally or generated external to the board and it must be routed to one of the RTSI lines Digital 1 0 Functions The digital I O DIG functions perform nonhandshaked digital line and port I O Refer to the NI DAQ Function Reference Online Help file to determine which functions your device supports DIG In Line Returns the digital logic state of the specified digital input line in the specified port DIG In Prt Returns digital input data from the specified digital I O port DIG Line Config Configures the specified line on a specified port for direction input or output DIG Out_Line Sets or clears the specified digital output line in the specified digital port National Instruments Corporation 3 57 NI DAQ User Manual for PC Compatibles Chapter 3 Software Overview DIG _Out_Prt DIG Prt_Config DIG Prt_Status Group Digital 1 0 Functions Writes digital output d
86. an sequence vector SCAN Sequence Retrieve Initiate multiple channel data acquisition SCAN Start C Check ongoing data acquisition status DAQ Check Data acquisition complete Yes Rearrange the data in your data acquisition buffer so that all data from each channel is stored in adjacent elements of your buffer SCAN Sequence_Demux for use in the SCAN_Sequence_Demux function Figure 3 11 Multirate Scanning NI DAQ User Manual for PC Compatibles 3 34 ni com Chapter 3 Software Overview Analog Output Function Group The Analog Output function group contains two sets of functions the Analog Output Ao functions which perform single D A conversions and the Waveform WFM functions which perform buffered D A conversions 3 Note Use the SCXI functions described later in this chapter for the SCXI 1124 analog output module One Shot Analog Output Functions Use the Analog Output functions to perform single D A conversions with analog output devices Refer to the NI DAQ Function Reference Online Help file to determine which functions your device supports AO Change Parameter Selects a specific parameter setting for the analog output section or analog output channel These parameters might be data transfer conditions filter settings or similar device settings AO _ Configure Records the output range and polarity selected for each analog output channel by t
87. ansfers will execute normally as long as neither of these problem conditions occur again Double Buffered Functions Double buffered functions exist for analog input DAQ analog output WFM digital input output DIG and general purpose counter GPCTR operations This section explains what each of the functions do and the order in which you should call them National Instruments Corporation 4 9 NI DAQ User Manual for PC Compatibles Chapter 4 NI DAQ Double Buffering Double Buffer Configuration Functions The Double Buffer Configuration functions enable and disable double buffering for input and output operations and you can select double buffering options if any are available The configuration functions are as follows DAQ DB Config e WFM DB Config e DIG DB Config GPCTR_Change_Parameter For analog input operations call DAQ_DB_ Config prior to calling DAQ Start ora SCAN Start to enable or disable double buffering For waveform operations call WFM_DB_ Config prior to calling WFM_Load to enable or disable double buffering For digital block input and output operations call DIG_DB_ Config prior to calling DIG_Block_In orDIG_ Block _Out to enable or disable double buffering For counter operations before calling GPCTR_Contro1 to start your counter call GPCTR_Change_Parameter to enable or disable continuous buffering with ND_Doub1le Counters transfer their data continuously not in half buffers Do
88. art is to loop back until all of the data has been input or output NI DAQ User Manual for PC Compatibles 3 68 ni com Chapter 3 Software Overview Digital Group Block I O Applications NI DAQ also contains group digital I O functions which operate on blocks of data Figure 3 24 outlines the basic steps for applications that use block I O Configure DIO 32F DIO 6533 DIO 32HS PCI 6115 and PCI 6120 i device groups for input and output Configure DIO 24 6025E devices AT MIO 16DE 10 DIO 96 Lab PC SCXI 1200 DAQCard 1200 or Yy DAQPad 1200 groups for input or output DIG Scan Setup DIG Grp_Config Alter handshaking mode DIG Grp Mode DIO 32F and DIO 6533 only Enable or disable pattern generation DIG Block _PG Config Enable or disable start and stop triggers DIG Trigger Config DIO 6533 only y Start block input y Start block output DIG Block_In DIG Block_Out Any more data to input or output Yes DIG Block_Check No Clear block operation if DIG_Block_Check did not DIG Block Clear Figure 3 24 Digital Block Input or Output Application National Instruments Corporation 3 69 NI DAQ User Manual for PC Compatibles Chapter 3 3 3 Software Overview Note The DIO 32F 653X DIO 24 6025E devices AT MIO 16DE 10 DIO 96 and Lab and 1200 devices all can perform group block operati
89. at the PPS keeps the subsecond counters synchronized The initial time for NI TIO clocks is specified in seconds from 12 00 a m January 1 of the current year You can think of this as Julian seconds if it is easier Most GPS receivers produce a PPS stream You must allow for a window of error when using PPS When you receive the time from the receiver you must set the clock up within 1 second If you wait any longer your clock will be off by 1 or more seconds The SetUpClockUsingPPS section shows pseudocode for ensuring that your clock has been set safely SetUpClockUsingPPS Comment Get the latest time from the RS 232 port of the receiver It has a Comment resolution of one second initialTime Satellite Receiver Time lastTime initialTime Comment This is for initialization While initialTime lastTime Comment Get the latest time lastTime Satellite Receiver Time Comment We now are at the beginning of the next second Comment This will minimize the chance of taking too long Comment to program the clock GPCTR_Control deviceNumber ND _CLOCK_x ND_RESET GPCTR_Set_Application deviceNumber ND_CLOCK x ND_SIMPLE_TIME_MSR NI DAQ User Manual for PC Compatibles 3 96 ni com Chapter 3 Software Overview GPCTR_Change_Parameter deviceNumber ND CLOCK x ND_SYNCHRONIZATION METHOD ND PULSE PER SECOND GPCTR_Change_ Parameter deviceNumber ND CLOCK x ND_SECONDS last Time GPCTR_Control deviceNumber
90. ata to the specified digital port Configures the specified port for direction input or output Returns a status word indicating the handshake status of the specified port The Group Digital I O DIG_Block DIG Grp and DIG_ SCAN functions perform handshaked I O on groups of ports Refer to the NI DAQ Function Reference Online Help file to determine which functions your device supports DIG Block _Check DIG Block Clear DIG Block In DIG Block Out DIG Block PG Config DIG Grp _ Config DIG Grp Mode DIG _Grp_ Status DIG In Grp NI DAQ User Manual for PC Compatibles 3 58 Returns the number of items remaining to be transferred after a DIG_Block_Inor DIG Block Out call Halts any ongoing asynchronous transfer allowing another transfer to be initiated Initiates an asynchronous data transfer from the specified group to memory Initiates an asynchronous data transfer from memory to the specified group Enables or disables the pattern generation mode of buffered digital I O Configures the specified group for port assignment direction input or output and size Configures the specified group for handshake signal modes Returns a status word indicating the handshake status of the specified group Reads digital input data from the specified digital group ni com DIG Out_Grp DIG_SCAN Setup DIG Trigger Config Double Buffered Digital 1 0 Functions Chapter 3 Software Overview
91. ata transfer After you start the operation you can call DIG_Block_Check to get the current progress of the transfer If the block operation completes prior to a DIG Block Check call DIG_Block_Check automatically calls DIG _Block_Clear which performs cleanup work The final step of a digital block operation is to call DIG_Block_ Clear DIG Block Clear performs the necessary cleanup work after a digital block operation You must call this function explicitly if DIG _Block_Check did not already call DIG_Block_ Clear Note DIG Block Clear halts any ongoing block operation Therefore call DIG _Block_Clear only if you are certain the block operation has completed or you want to stop the current operation NI DAQ User Manual for PC Compatibles 3 70 ni com Chapter 3 Software Overview Digital Double Buffered Group Block 1 0 Applications You also can configure group block operations as double buffered operations for DIO 32 devices With double buffered operations you can do continuous input or output with a limited amount of memory See the Double Buffered I O section later in this chapter for an explanation of double buffering Figure 3 25 outlines the basic steps for digital double buffered group block I O applications National Instruments Corporation 3 71 NI DAQ User Manual for PC Compatibles Chapter 3 Software Overview y Configure groups for input or output DIG_Grp_Config Enable double buffering DIG_DB Co
92. ating 3 or 4 With rising edge triggered gating a counter can measure the time interval National Instruments Corporation 3 89 NI DAQ User Manual for PC Compatibles Chapter 3 Software Overview tl in Figure 3 33 between two rising edges of the gate signal With falling edge triggered gating a counter can measure the time interval between two falling edges of the gate signal After you call CTR_Config and apply the signal being measured to the appropriate gate you can call CTR_Period to initiate period measurement The specified counter starts counting on the first gate edge and latches the counter value to the onboard Hold Register after the counter detects a second gate edge After each period measurement the counter reloads itself with a 0 and starts a new measurement Figure 3 34 shows a continuous period measurement SOURCE Timebase GATE Periodic Signal CTR_EvRead Latched Count Period 1 1 gt i lt lt I act eee cL he Figure 3 34 Continuous Period Measurement While the measurement is occurring call CTR_EvRead to retrieve the counter value saved in the Hold Register The period is then equal to the value returned by CTR_EvRead timebase If you choose an improper timebase frequency CTR_EvRead retrieves a smaller count value A small count indicates that the timebase frequency is either too low or too high compared to the gate signal I
93. ation 3 5 NI DAQ User Manual for PC Compatibles Chapter 3 Software Overview After your application receives an event message it can carry out the appropriate task such as updating the screen or saving data to disk To restart your data acquisition process after it completes you do not need to call the message configuration calls again They remain defined as long as your application does not explicitly remove them or call Init_DA Brds To add or remove a message first clear your data acquisition process Then call one of the three event message configuration functions NI DAQ Events in Visual Basic for Windows ActiveX Controls for Visual Basic Unlike standard control flow programming languages event occurrences drive Visual Basic code You interact with outside events through the properties and procedures of a control For any given control there is a set of procedures called event procedures that affect that control For example a command button named Run has a procedure called Run_Click that is called when you click on the Run button If you want something to run when you click the Run button enter code in the Run_Click procedure When a program starts executing Visual Basic looks for events related to controls and calls control procedures as necessary You do not write an event loop There are three NI DAQ ActiveX controls for Visual Basic applications e General Data Acquisition Event dagevent ocx e Analog Trigg
94. ation for clocked digital I O when you have a group that is written to or read from based on the output of a counter The DIG Block _PG Config function enables the pattern generation mode of digital I O When pattern generation is enabled a subsequent DIG _Block_Inor DIG Block_Out call automatically uses this mode Each group for the DIO 32F and 653X devices has its own onboard counter so that each can simultaneously run in this mode at different rates Use an external counter by connecting its output to the appropriate REQ pin at the T O connector For an input group pattern generation is analogous to a data acquisition operation but instead of reading analog input channels NI DAQ reads the digital ports For an output group pattern generation is analogous to waveform generation but instead of writing voltages to the analog output channels NI DAQ writes digital patterns to the digital ports The DIO 32F 653X PCI 6115 and PCI 6120 use DMA to service pattern generation However certain buffers require NI DAQ to reprogram the DMA controller during the pattern generation The extra time needed to reprogram increases the minimum request interval thus decreasing the maximum rate unless you use dual DMA Refer to Chapter 4 NI DAQ Double Buffering for more information ny Note For the AT DIO 32F DIG_Block_Inand DIG Block _Out return a warning if it is necessary to reprogram the DMA controller Also page boundaries in a buffer that is to b
95. bit USB MIO DAQPad 6052E for 1394 16 16 bit 1394 MIO DAQPad 6052E for USB 16 16 bit USB MIO National Instruments Corporation xiii NI DAQ User Manual for PC Compatibles About This Manual Table 1 MIO and Al Device Classifications Continued Number of SE Device Channels Bit Type Functionality DAQPad 6070E 16 12 bit 1394 MIO NEC AI 16E 4 16 12 bit NEC Al NEC AI 16XE 50 16 16 bit NEC Al NEC MIO 16E 4 16 12 bit NEC MIO NEC MIO 16XE 50 16 16 bit AI NEC MIO NI 6222 for PCI 24 16 bit AI 12 bit AO PCI MIO NI 6222 for PXI 24 16 bit AI 12 bit AO PXI MIO NI 6224 for Ethernet 56 16 bit AI 12 bit AO Ethernet MIO PCI 6023E 16 12 bit PCI AI PCI 6024E 16 12 bit PCI MIO PCI 6025E 16 12 bit PCI MIO PCI 6031E MIO 64XE 10 64 16 bit PCI MIO PCI 6032E AI 16XE 10 16 16 bit PCI AI PCI 6033E AI 64XE 10 64 16 bit PCI AI PCI 6034E 16 16 bit PCI AI PCI 6035E 16 16 bit AI 12 bit AO PCI MIO PCI 6052E 16 16 bit PCI MIO PCI 6053E 64 16 bit PCI MIO PCI 6071E MIO 64E 1 64 12 bit PCI MIO PCI 6110E 4 DIFF only 12 bit AI 16 bit AO PCI MIO PCI 6111E 2 DIFF only 12 bit AI 16 bit AO PCI MIO PCI 6115 4 DIFF only 12 bit PCI MIO PCI 6120 4 DIFF only 16 bit PCI MIO PCI MIO 16E 1 16 12 bit PCI MIO PCI MIO 16E 4 16 12 bit PCI MIO PCI MIO 16XE 10 16 16 bit PCI MIO PCI MIO 16XE 50 16 16 bit PCI MIO PXI 6011E 16 16 bit PXI MIO
96. ble buffered functions configuration functions 4 10 DAQ_DB_Config 3 23 4 10 DIG_DB_Config 3 59 4 10 ni com GPCTR_Change_Parameter 3 93 4 10 WFM_DB_Config 4 10 digital I O functions applications double buffered I O 3 75 to 3 76 group block I O applications 3 69 to 3 70 DIG_DB_Config 3 59 4 10 DIG_DB_HalfReady 3 59 4 12 DIG_DB_ Transfer 3 59 4 11 HalfReady functions 4 11 to 4 12 DAQ_DB_HalfReady 3 24 4 12 DIG_DB_HalfReady 3 59 4 12 GPCTR_Read_Buffer 4 12 WFM_DB_HalfReady 4 12 low level double buffered data acquisition functions 3 23 to 3 24 application tips 3 31 to 3 32 DAQ_DB_ Config 3 23 4 10 DAQ_DB_HalfReady 3 24 4 12 DAQ_DB_ Transfer 3 24 4 11 transfer functions 4 10 to 4 11 DAQ_DB_ Transfer 3 24 4 11 DIG_DB_ Transfer 3 59 4 11 GPCTR_Read_Buffer 4 11 WFM_DB _ Transfer 4 11 double buffered waveform generation applications 3 47 to 3 48 DSA devices RTSI connections 3 103 E E series devices Calibrate_E_ Series function 3 4 counter usage 3 50 FIFO lag effect 3 51 to 3 52 RTSI bus connections 3 103 event counting 3 86 to 3 89 concatenated event counting 3 88 to 3 89 National Instruments Corporation l 7 Index CTR_EvCount function 3 77 CTR_EvRead function 3 77 flow chart 3 82 frequency measurement 3 87 to 3 88 overview 3 86 pulse width measurement 3 86 to 3 87 time lapse measurement 3 87 timer event counting figure 3 86 event message functions 3 5 See al
97. buffered configure a buffer for use during the acquisition using the GPCTR_Config_ Buffer function Next change some of the counter attributes depending on your type of application by calling GPCTR_Change_Parameter For example set the counter source to the internal 100 kHz timebase set the initial value of the counter to 0 or set the output mode of the counter to pulse mode Arm the counter with the settings you made by calling GPCTR_Control If you configure the counter to use a start trigger the counter will not start counting until it receives the start trigger signal Otherwise the counter immediately begins counting Check the status of the counters by using the GPCTR_Watch function If you are doing a continuous buffered operation read the buffer by calling GPCTR_Read_Buffer When the operation has completed or you want to abort the operation reset the counter by calling GPCTR_Control with appropriate control code NI DAQ User Manual for PC Compatibles 3 94 ni com Chapter 3 Software Overview For more about GPCTR functions refer to the GPCTR_Set_Application function description in NI DAQ Function Reference Online Help file Clocks or Time Counters NI TIO based devices have built in clocks which are specialized time counters that retrieve current time and timestamp one or more digital triggers The number of clocks available depends on the number of NI TIO chips on your device Most devices have one clock per NI TIO chip
98. by the ability of the CPU to process the data within a given period of time Specifically data must be processed by the application at least as fast as the rate at which the device is writing or reading data For many applications this requirement depends on the speed and efficiency of the computer system and programming language NI DAQ User Manual for PC Compatibles 4 12 ni com Transducer Conversion Functions This chapter describes the NI DAQ Transducer Conversion functions NI DAQ includes source code for these functions The Transducer Conversion functions convert analog input voltages read from thermocouples RTDs thermistors and strain gauges into temperature or strain units RTD_Convert Supplied single voltage and voltage buffer routines convert voltages read from an RTD into resistance and then into temperature in units for Celsius Fahrenheit Kelvin or Rankine Strain Convert Supplied single voltage and voltage buffer routines convert voltages read from a strain gauge into measured strain using the appropriate formula for the strain gauge bridge configuration used Thermistor_ Convert Supplied single voltage and voltage buffer routines convert voltages read from thermistors into temperature Thermocouple Convert Supplied single voltage and voltage buffer routines convert voltages read from B E J K N R S or T type thermocouples into temperature in Celsius Fahrenheit Kelvin or Rankine NI DAQ i
99. ce and calibrates its own A D and D A circuits without manual adjustments by the user an analog input that is measured with respect to a common ground See master slave a programmed event that triggers an event such as data acquisition NI 54XX boards only an entry in a sequence list System Timing Controller 1 hardware a property of an event that is synchronized to a reference clock 2 software a property of a function that begins an operation and returns only when the operation is complete NI DAQ User Manual for PC Compatibles G 10 ni com T TC throughput rate transfer rate TSR U unipolar USB V V VDC VPICD VXI National Instruments Corporation G 11 Glossary terminal count the data measured in bytes s for a given continuous operation calculated to include software overhead the rate measured in bytes s at which data is moved from source to destination after software initialization and set up operations the maximum rate at which the hardware can operate Terminate and Stay Resident a signal range that is always positive for example 0 to 10 V universal serial bus volt volts direct current Virtual Programmable Interrupt Controller Device VMEbus eXtensions for Instrumentation NI DAQ User Manual for PC Compatibles Index Numbers 1200 series devices See Lab and 1200 series devices 445 land 4551 devices counter usage 3 50 FIFO lag effect 3 51 to 3 52 60
100. ce or 671X device You can simultaneously change the voltages at all the analog output channels The final steps in Figure 3 13 form a simple loop New voltages are output until the data ends Analog Output with Software Update Application Another application option is to enable later software updates Like the external update mode voltages written to the device are not immediately output Instead the device does not output the voltages until you call AO_Update In later software update mode the device changes voltages simultaneously at all the channels Figure 3 14 illustrates a modified version of the flowchart in Figure 3 13 National Instruments Corporation 3 37 NI DAQ User Manual for PC Compatibles Chapter 3 Software Overview Account for changes in the jumper settings Enable software voltage update AO_Configure Output voltage to board AO _ VWrite Wait until you are ready to output voltage Update Yes Output voltage from board AO Update Done outputting data Figure 3 14 Analog Output with Software Updates The first modification you make is to enable later internal updates when you call AO_Configure The next change which follows the AO_VWrite step is the decision to wait or to output the voltage If you want the voltage to be output your application must call AO_Update to write out the voltage The rest of the flowchart is identical to Figure 3 13 B N
101. ce such as a DAQ board or a GPIB interface board dynamic signal acquisition digital signal processing D subminiature connector electronically erasable programmable read only memory ROM that can be erased with an electrical signal and reprogrammed Enhanced Graphics Adapter Extended Industry Standard Architecture a message sent by an event driven program a program with a loop that waits for events to occur a voltage pulse from an external source that triggers an event such as A D conversion NI DAQ User Manual for PC Compatibles Glossary FIFO gain group GPS GPS receiver GUI H VO ID IDE A first in first out memory buffer the first data stored is the first data sent to the acceptor FIFOs are often used on DAQ devices to temporarily store incoming or outgoing data until that data can be retrieved or output For example an analog input FIFO stores the results of A D conversions until the data can be retrieved into system memory a process that requires the servicing of interrupts and often the programming of the DMA controller This process can take several milliseconds in some cases During this time data accumulates in the FIFO for future retrieval With a larger FIFO longer latencies can be tolerated In the case of analog output a FIFO permits faster update rates because the waveform data can be stored on the FIFO ahead of time This again reduces the effect of latencies associated with getting th
102. conventional driver software is single buffering In single buffered input operations a fixed number of samples are acquired at a specified rate and transferred into computer memory After the memory buffer stores the data the computer can analyze display or store the data to the hard disk for later processing Single buffered output operations output a fixed number of samples from computer memory at a specified rate After outputting data the buffer can be updated with new or freed data Single buffered operations are relatively simple to implement can usually take advantage of the full hardware speed of the DAQ device and are very useful for many applications The major disadvantage of single buffered operations is that the amount of data that can be input or output is limited to the amount of free memory available in the computer National Instruments Corporation 4 1 NI DAQ User Manual for PC Compatibles Chapter 4 NI DAQ Double Buffering In double buffered input operations the data buffer is configured as a circular buffer For input operations the DAQ device fills the circular buffer with data When the end of the buffer is reached the device returns to the beginning of the buffer and fills it with data again This process continues indefinitely until it is interrupted by a hardware error or cleared by a function call Double buffered output operations also use a circular buffer In this case however the DAQ device retrieves
103. d group 2 One group is configured as an input group and the other is configured as an output group Because these devices only have one digital port a group can consist of any combination of digital lines 0 7 For example group 1 can be configured as an input group containing lines 0 4 and group 2 as an output group containing lines 5 7 Alternatively group 1 can be configured as an output group containing lines 1 3 5 7 and group 2 as an input group containing lines 0 2 4 6 A portion of the eight available lines can also be configured for group operations with the remaining unused lines configured for NI DAQ User Manual for PC Compatibles 3 56 ni com Chapter 3 Software Overview immediate digital operations However both groups cannot be configured for input or output at the same time Although a group can consist of non contiguous lines there is no logical grouping of the lines and an 8 bit value is still passed from the input function or returned from the output function For example if a group is configured for output with lines 0 1 2 4 and the group is to be written with all ones the hex value of 0x17 is passed to the function instead of OxF Group operations are buffered operations only which means immediate digital operations are not possible with these devices using handshaking Because all group operations are buffered there is no support for a status operation indicating when an input operation has been latched to or
104. d in the executable files Note Use the 32 bit nidag32 d11 If you are programming in C or C link in the appropriate import library See the following sections for language specific details Using function prototypes is a good programming practice That is why NI DAQ is packaged with function prototype files for different Windows development tools The installation utility copies the appropriate prototype files for the development tools you choose If you are not using any of the development tools that NI DAQ works with you must create your own function prototype file National Instruments Corporation 2 1 NI DAQ User Manual for PC Compatibles Chapter 2 Fundamentals of Building Windows Applications Creating a Windows Application Using Microsoft Visual C This section assumes that you will be using the Microsoft Visual C Integrated Development Environment IDE to manage your code development and that you are familiar with the IDE Developing an NI DAQ Application To develop an NI DAQ application follow these general steps 1 Example Programs Open an existing or new Visual C project to manage your application code Create files of type c C source code or cpp C source code and add them to the project Make sure you include the NI DAQ header file nidaq h as such in your source code files include nidaq h You may also want to include nidagens h and nidagerr h Optionally you can include other
105. d it or until an acquisition error has occurred Low Level Data Acquisition Functions These functions are low level primitives used for setting up starting and monitoring asynchronous data acquisition operations Refer to the NI DAQ Function Reference Online Help file to determine which functions your device supports DAQ Check DAQ Clear DAQ Config DAQ Monitor National Instruments Corporation 3 21 Checks if the current data acquisition operation is complete and returns the status and the number of samples acquired to that point Cancels the current data acquisition operation both single channel and multiple channel scanned and reinitializes the data acquisition circuitry Stores configuration information for subsequent data acquisition operations Returns data from an asynchronous data acquisition in progress During a multiple channel acquisition you can call DAQ Monitor to retrieve data from a single channel or from all channels being scanned Using the oldest newest mode you can specify whether DAQ Monitor returns sequential oldest blocks of data or the most recently acquired newest blocks of data NI DAQ User Manual for PC Compatibles Chapter 3 Software Overview DAQ Rate DAQ Set _Clock DAQ Start DAQ StopTrigger Config DAQ VScale Lab_ISCAN Check Lab_ISCAN Start SCAN_Demux SCAN Sequence _Demux NI DAQ User Manual for PC Compatibles 3 22 Converts a data acquisition
106. data from the circular buffer for output When the end of the buffer is reached the device begins retrieving data from the beginning of the buffer again Unlike single buffered operations double buffered operations reuse the same buffer and are therefore able to input or output an infinite number of data points without requiring an infinite amount of memory However for double buffering to be useful there must be a means by which to access the data for updating storing and processing The next two sections explain how to access the data for double buffered input and output operations Double Buffered Input Operations The data buffer for double buffered input operations is configured as a circular buffer In addition NI DAQ logically divides the buffer into two equal halves no actual division exists in the buffer By dividing the buffer into two halves NI DAQ can coordinate user access to the data buffer with the DAQ device The coordination scheme is simple NI DAQ copies data from the circular buffer in sequential halves to a transfer buffer you create You can process or store the data in the transfer buffer however you choose NI DAQ User Manual for PC Compatibles 4 2 ni com Chapter 4 NI DAQ Double Buffering Figure 4 1 illustrates a series of sequential data transfers Incoming Device Data l Circular Buffer a b 5 Transfer Buffer a
107. dule channels The respective chapters on the DIO 96 DIO 24 AT MIO 16DE1 10 6025E and DIO 32F and 653Xs devices in the DAQ Hardware Overview Guide list the onboard port numbers used for each device type if the SCXI 1162 HV or SCXI 1163 R is configured for parallel mode The MIO and AI devices Lab PC and SCXI 1200 cannot use the SCXI 1162 HV or the SCXI 1163 R in parallel mode National Instruments Corporation 3 127 NI DAQ User Manual for PC Compatibles NI DAQ Double Buffering Overview This chapter describes using double buffered data acquisitions with NI DAQ This chapter applies to counter operations However you can read samples of any size Conventional data acquisition software techniques such as single buffered data acquisition work well for most applications However more sophisticated applications involving larger amounts of data at higher rates require more advanced techniques for managing the data One such technique is double buffering National Instruments uses double buffering techniques in its driver software for continuous uninterrupted input or output of large amounts of data This chapter discusses the fundamentals of double buffering including specific information on how the NI DAQ double buffered functions work i Note Input and output refer to both digital and analog operations in this chapter Single Buffered Versus Double Buffered Data The most common method of data buffering found in
108. e simultaneous sampling device Italic text in this font denotes text that is a placeholder for a word or value that you must supply Refers to the NI DAQ software for PC compatibles unless otherwise noted Refers to the NI 4551 NI 4552 DAQCard 6601 PCI 6601 PCI 6602 PXI 6602 PCI 6608 PXI 6608 Refers to the IBM PC XT IBM PC AT and compatible computers Refers to the National Instruments products that use the high performance expansion bus architecture originally developed by Intel Refers to PCI eXtensions for Instrumentation derived from the CompactPCI standard Refers to an SCXI configuration where either an SCXI 2000 chassis or an SCXI 2400 remote communications module is connected to the PC serial port SCXI 1102 B C refers to the SCXI 1102 SCXI 1102B and SCXI 1102C SCXI 1120 D refers to the SCXI 1120 and SCXI 1120D SCXI 1104 C refers to the SCXI 1104 and SCXI 1104C Refers to the SCXI 1100 SCXI 1101 SCXI 1102 SCXI 1104 SCXI 1104C SCXI 1112 SCXI 1120 SCXI 1120D SCXI 1121 SCXI 1122 SCXI 1125 SCXI 1140 SCXI 1141 SCXI 1142 SCXI 1143 and SCXI 1520 Refers to the SCXI 1124 module Refers to the SCXI 1000 SCXI 1000DC SCXI 1001 and SCXI 2000 Refers to the SCXI 1160 SCXI 1161 SCXI 1162 SCXI 1162HV SCXI 1163 and SCXI 1163R Refers to the SCXI 1190 SCXI 1191 SCXI 1127 and SCXI 1128 Refers to the PCI 6110E PCI 6111E PCI 6115 PXI 6115 PCI 6120 PXI 6120 NI 4451 for PCI NI 4452
109. e used for 32 bit digital pattern generation cause unpredictable results for AT bus computer users regardless of the request interval used For the DIO 32F another option is to use the utility function Align DMA Buffer to avoid the negative effects of page boundaries in the following cases e When using digital I O pattern generation at small request intervals for buffers with page boundaries e When using 32 bit digital I O pattern generation at any speed To use Align _ DMA Buffer however you must allocate a buffer that is larger than the sample count to make room for Align DMA Buffer to move the data around When the buffer is aligned make the normal calls to DIG_Block_Inand DIG Block_Out A call to DIG_Block Clear either directly or indirectly through DIG_Block_ Check unaligns the data buffer if the data buffer was previously aligned by a call to NI DAQ User Manual for PC Compatibles 3 74 ni com Chapter 3 Software Overview Align DMA Buffer To use the Align DMA Buffer utility function follow these steps 1 Allocate a buffer twice as large as the number of data samples you are generating If you are using digital output build your digital pattern in the buffer Call DIG_Grp_ Config for port assignment Call DIG_Block_PG Config to enable pattern generation te SS Call Align DMA Buffer as described in the NI DAQ Function Reference Online Help file 6 Call DIG_Block_ In or DIG Block _Out with the aligned buffer to
110. e appropriate root Thus these conversion routines are accurate only for temperatures above 0 C Your RTD documentation should give you Ro and the A and B coefficients for the Callendar Van Diisen equation The most common RTDs are 100 Q platinum RTDs that either follow the European temperature curve also known as the DIN 43760 standard or the American curve The values for A and B are as follows e European Curve DIN 43760 A 3 90802 x 10 B 5 80195 x 10 7 a 3 85 x 10 3 1 492 e American Curve A 3 9784 x 10 B 5 8408 x 10 7 a 3 92 x 103 1 492 National Instruments Corporation 5 3 NI DAQ User Manual for PC Compatibles Chapter 5 Transducer Conversion Functions Some RTD documentation contains values for amp and d from which you can calculate A and B using the following equations A 0 1 0 100 B a0 10 000 1007 where is the temperature coefficient at T 0 C C a 8 1 000 000 where B is a characteristic of your RTD similar to the o and equation coefficients Strain_Convert and Strain_Buf_Convert These functions convert a voltage or voltage buffer that NI DAQ read from a strain gauge to units of strain Parameter Discussion The bridgeConfig integer indicates in what type of bridge configuration the strain gauge is mounted Figure 5 1 shows all the different bridge configurations and the corresponding values that you should pass in bridgeConfig Vex is the exc
111. e clock source and the accuracy of the synchronization pulse The source of your IRIG B stream determines the accuracy of the synchronization pulse You can calculate the clock accuracy by adding the resolution of the clock source and the accuracy of the synchronization pulse both in nanoseconds For example if you have a 50ns resolution and a 100ns synchronization pulse accuracy your clock accuracy is as follows 50ns 100ns 150ns Example Clock in a Measurement System The block diagram in Figure 3 39 illustrates a system in which all the clock capabilities of the TIO can be exploited The chassis has its TIO board 6602 synchronized to a GPS but the other modules are not clock capable Each of the other modules is programmed to assert a PXI trigger when it receives an event The TIO board is set up to time stamp the triggers of the other modules as well as to save the clock value on the first time stamp With the system configured you can determine the precise relationship of all triggers throughout the system to correlate the data If you clone the system you can correlate all the data from the individual systems as a whole NI DAQ User Manual for PC Compatibles 3 98 ni com Chapter 3 Software Overview PPS GPS Revr y RS232 Controller 6602 E Series 1407 t Trigger 1 Trigger 2 Figure 3 39 Example Clock in a Measurement System Sample Use Cases The fo
112. e data from system memory to the DAQ device the factor by which a signal is amplified sometimes expressed in decibels a collection of digital ports combined to form a larger entity for digital input and or output Global Positioning System A satellite based system created and maintained by the U S Department of Defense that allows its users to determine their position velocity and time An instrument that receives signals from GPS satellites graphical user interface hertz input output identification Integrated Development Environment NI DAQ User Manual for PC Compatibles G 6 ni com TEEE import library interrupt interrupt latency IRIG IRQ ISA iterations J Julian kS Kword linker LSB National Instruments Corporation G 7 Glossary Institute of Electrical and Electronics Engineers a file that contains information the linker needs to resolve external references to exported dynamic link library DLL functions so the system can locate the specified DLL and exported DLL functions at run time a computer signal indicating that the CPU should suspend its current task to service a designated activity the delay between the time hardware asserts an interrupt and when the interrupt service routine is activated Inter Range Instrumentation Group A pulse modulated signal normally produced by a GPS receiver interrupt request Industry Standard Architecture repetitions of the buffer
113. e function This function waits until the data to be transferred is available before returning You can execute DAQ DB Transfer repeatedly to return sequential half buffers of the data Data Acquisition Application Tips Lab and 1200 Device Counter Timer Signals For the Lab and 1200 devices counter A2 produces the total sample interval for data acquisition timing However if the total sample interval is greater than 65 535 us counter BO generates the clock for a slower timebase which counter A2 uses for the total sample interval Thus the ICTR_Setup and ICTR_Reset functions cannot use counter BO for the duration of the data acquisition operation In addition the Waveform Generation functions cannot use counter BO if the total update interval for waveform generation is also greater than 65 535 us and counter BO must produce a timebase for waveform generation different from the timebase counter BO produced for data acquisition If waveform generation is not in progress counter BO is available for data acquisition if you have made no ICTR_Setup call on counter BO since startup or if you have made an ICTR_Reset call on counter BO If waveform generation is in progress and is using counter BO to obtain the timebase required to produce the total update interval counter BO is only available for data acquisition if this timebase is the same as that required by the Data Acquisition functions to produce the total sample interval In this case
114. e the various gating modes of CTR_Config to control counting Figure 3 31 illustrates timer event counting SOURCE Event Signal Start Stop Signal CTR_EvRead Count 1 2 3 4 5 5 GATE Figure 3 31 Timer Event Counting For pulse width measurement configure a counter to count for the duration of a pulse For this application you can use any timebase including an external clock connected to the counter SOURCE input Use level gating modes for pulse width measurements in which the pulse to be measured is connected to the counter GATE input Pulse width is then equal to event count timebase period Figure 3 32 shows a typical pulse width measurement NI DAQ User Manual for PC Compatibles 3 86 ni com Chapter 3 Software Overview A SOURCE Timebase l GATE Pulse l CTR_EvRead Count 1 2 3 4 5 6 7 8 8 Pulse Width 8 ti Figure 3 32 Pulse Width Measurement For time lapse measurement configure a counter to count from the occurrence of some event For this application you can use any timebase including an external clock connected to the counter SOURCE input You can use edge triggered gating modes if a single counter performs the event counting and if cont 0 in CTR_EvCount In this case the starting event is an edge applied to the GATE input of the
115. e_Chan Do you wish to take more data while the module is in Hold mode Maintain Hold mode Yes Put the module back into Track mode to sense the new input values SCXI_Track_Hold_Setup Have you acquired all the data you need from this module No Figure 3 43 Single Channel or Software Scanning Operation Using a Simultaneous Sample and Hold Module in Multiplexed Mode NI DAQ User Manual for PC Compatibles 3 116 ni com Chapter 3 Software Overview Notice the similarities between Figure 3 43 and Figure 3 44 which shows the corresponding application in parallel mode The SCXI_Track_Hold_Setup calls and the SCXI_Track_Hold_ Control calls are the same In multiplexed mode however an SCXI_Single Chan Setup call is required to select the multiplexed channel and appropriately route the output to the DAQ device or SCXI 1200 module The SCXI_Change_Chan call can change the channel on the module either while the module is in hold mode or after the module has been returned to track mode Figure 3 43 shows the function call sequence of a channel scanning application in multiplexed mode Remember that only the MIO and AI devices the Lab PC the SCXI 1200 and the DAQCard 1200 work with channel scanning in multiplexed mode You can use any combination of module types in a scanning operation If any track and hold modules are to be scanned use interval scanning if you are using a plug in DAQ dev
116. edges of the signal applied to the CLK input The counter GATE input gates counting operations If your device uses an 8253 or MSM82C54 chip refer to the data sheet in your device specific manual to see how the GATE inputs affect the counting operation in different counting modes Interval Counter Timer Application Tips NI DAQ interval counter functions interface to the six different counting modes of 8253 counter chips on these devices To choose the mode of operation call ICTR_Setup Refer to the ICTR_Setup function description in the NI DAQ Function Reference Online Help file for descriptions of all six different counter modes After a counter is armed with ICTR_Setup call ICTR_Read to retrieve the current counter value Furthermore to halt any counter operation call ICTR_Reset NI DAQ User Manual for PC Compatibles 3 92 ni com General Purpose Counter Timer Functions Chapter 3 Software Overview Use the General Purpose Counter Timer GPCTR functions with the E Series 622X1 660X 671X NI TIO based and DSA devices Refer to the GPCTR functions in the NI DAQ Function Reference Online Help file for a detailed description of how to use the GPCTR functions for a variety of applications GPCTR_Change_ Parameter GPCT GPCT GPCT R Config Buffer R Control R Read Buffer GPCTR_Set_Application GPCTR_Watch National Instruments Corporation 3 93 Customizes the counter operation to fit the requirements
117. egins the waveform generation after you call it If the number of iterations is nonzero WFM_Op does not return until the waveform generation is done and all cleanup work is complete Setting the iterations equal to 0 signals NI DAQ to place the waveform generation in continuous double buffered mode In continuous double buffered mode waveform generation occurs in the background and the WFM_Op function returns immediately to your application See the Double Buffered Waveform Generation Applications section later in this chapter for more information The second option to start a waveform generation is to call the following sequence of functions 1 WFM_Group_Setup required only for the AT AO 6 10 to assign one or more analog output channels to a group 2 WFM_ Load to assign a waveform buffer to one or more analog output channels National Instruments Corporation 3 41 NI DAQ User Manual for PC Compatibles Chapter 3 Software Overview 3 WFM_Rate to convert a data output rate to a timebase and an update interval that generates the rate you want WFM_Rate only supports some devices Because it does not have a device number parameter it cannot return an error if you use it with a non supported device See the NI DAQ Function Reference Online Help file for supported devices 4 WFM ClockRate or WFM Set Clock to set the update rate see the NI DAQ Function Reference Online Help file to find out which function supports your device
118. ement has Index 1 andsoon You have only one procedure for each type of event custom control however you can determine which control array element caused the event to occur by examining the Index property e You can place multiple controls from the Visual Basic Tool Box onto the form Each individual custom control of the same type is then distinguished by the number after the name of the custom control such as GeneralDAQEvent1 GeneralDAQEvent2 and so on Consequently you can have separate procedures for each custom control such as GeneralDAQEvent1 Fire GeneralDAQEvent2_ Fire and so on General DAQ Event Example The following steps provide an outline of how to use the General DAQ Event control in a Visual Basic program A working knowledge of Visual Basic is assumed otherwise this example is complete except for error checking 1 To use the GeneralDAQEvent control you must first include the proper control into your project e Ifyou are using Visual Basic 4 0 32 bit select the Tools Custom Controls option and select the National Instruments GeneralDA QEvent custom control e Ifyou are using Visual Basic 5 0 select the Project Components option and select the National Instruments GeneralDA QEvent custom control In either version if you do not find the custom control listed click on the Browse button and find the custom control in the NI DAQ subdirectory under your Windows directory National Instruments Corpo
119. eneral DAQ Event control to 1 True 3 Invoke the GeneralDAQEventn Refresh method to set the DAQ Event in the NI DAQ driver Each subsequent use of GeneralDAQEventn Refresh deletes the old DAQ Event and sets a new one with the current set of properties NI DAQ User Manual for PC Compatibles 3 8 ni com Chapter 3 Software Overview 4 Start an asynchronous data acquisition or generation operation 5 When the selected event occurs the GeneralDAQEventn Fire procedure is called You can perform the necessary event processing within this procedure such as updating a global count variable or toggling digital I O lines The GeneralDAQEventn_ Fire procedure is prototyped as follows Sub GeneralDAQEventn_ Fire DoneFlag As Integer Scans As Long The parameter DoneFlag equals 1 if the acquisition was over when the DAQ Event fired Otherwise it is 0 Scans equals the number of the scan that caused the DAQ Event to fire For a detailed example of how to use the General DAQ Event control in a Visual Basic program please see the General DAQ Event example at the end of the NI DAQ Events in Visual Basic for Windows section Analog Trigger Event Use the Analog Trigger Event control to configure and enable an analog trigger See the Event Message Functions section earlier in this chapter for a definition of the analog trigger Table 3 2 lists the properties for the Analog Trigger Event control Table 3 2 Analog Trigger Event Control P
120. eneration The first way is to call the high level function WFM_Op The second way is to call the following sequence of functions WFM_Group_Setup only required on the AT AO 6 10 WFM_Load WFM_ClockRate or WFM_Set_Clock WFM_Group_Control operation START The WFM_Group_ Setup function assigns one or more analog output channels to a group The WFM_Load function assigns a waveform buffer to one or more analog output channels This buffer is called a circular buffer The WFM_ClockRate and WFM_Set_Clock functions see the NI DAQ Function Reference Online Help file for the function that supports your device assign an update rate to a group of analog output channels Calling WFM_Group_Control operation START starts the background waveform generation WFM_Group Control returns to your application after the waveform generation begins After the operation begins you can perform unlimited transfers to the circular waveform buffer To transfer data to the circular buffer call the WFM_DB_ Transfer function After you call the function NI DAQ waits until it is able to transfer the data before returning to the application To avoid the waiting period you can call WFM_DB HalfReady to determine if the transfer can be made immediately If WFM_DB HalfReady indicates NI DAQ is not ready for a transfer your application is free to do other processing and check the status later After the final transfer you can call WFM_Check to get the current transfer
121. equence created by NI DAQ as a result of a previous call to SCAN Sequence Setup SCAN Sequence Setup Initializes the device for a multirate scanned data acquisition operation Initialization includes selecting the channels to be scanned assigning gains to these channels and assigning different sampling rates to each channel by dividing down the base scan rate SCAN Setup Initializes circuitry for a scanned data acquisition operation Initialization includes storing a table of the channel sequence and gain setting for each channel to be digitized SCAN Start Initiates a multiple channel scanned data acquisition operation with or without interval scanning and stores its input in an array Low Level Double Buffered Data Acquisition Functions These functions are low level primitives used for setting up and monitoring asynchronous double buffered data acquisition operations Refer to the NI DAQ Function Reference Online Help file to determine which functions your device supports DAQ DB Config Enables or disables double buffered data acquisition operations National Instruments Corporation 3 23 NI DAQ User Manual for PC Compatibles Chapter 3 Software Overview DAQ DB HalfReady Checks if the next half buffer of data is available during a double buffered data acquisition DAQ DB Transfer Transfers half of the data from the buffer being used for double buffered data acquisition to another buffer which is passed to th
122. er Measurement amp Automation Explorer is a Windows based application that you use to configure and view National Instruments DAQ device settings under Windows 2000 NT 98 95 i Note To use Measurement amp Automation Explorer quit any applications that are performing DAQ operations Double click the Measurement amp Automation icon on your desktop to run Measurement amp Automation Explorer Refer to the Measurement amp Automation Explorer online help for more information and detailed instructions National Instruments Corporation 1 7 NI DAQ User Manual for PC Compatibles Fundamentals of Building Windows Applications This chapter describes the fundamentals of creating NI DAQ applications in Windows 2000 NT 98 95 The following section contains general information about building NI DAQ applications describes the nature of the NI DAQ files used in building NI DAQ applications and explains the basics of making applications using the following tools Borland C for Windows e Microsoft Visual C e Microsoft Visual Basic If you are not using the tools listed consult your development tool reference manual for details on creating applications that call DLLs The NI DAQ Libraries 3 The NI DAQ for Windows function libraries are DLLs which means that NI DAQ routines are not linked into the executable files of applications Only the information about the NI DAQ routines in the NI DAQ import libraries is store
123. er allocation you must lock memory with GlobalLock to use a buffer of memory You can use the memory handle returned by GlobalLock in place of the buffer parameter in NI DAQ API functions that accept buffers Align DMA Buffer DAQ DB Transfer DAQ Monitor DAQ Op DAQ Start DIG Block _In DIG Block Out DIG DB Transfer GPCTR_Config_ Buffer GPCTR_Read_ Buffer Lab ISCAN Op Lab _ISCAN Start SCAN Op SCAN Start SCAN Sequence _Demux WFM DB Transfer WFM Load WFM_Op The NI DAQ header file declares the buffer parameter As Any After using the memory you must unlock memory with GlobalUnlock and free it with GLobalFree Ss Note If you allocate memory from GlobalAlloc you must call GlobalLock on the memory object before passing it to NI DAQ National Instruments Corporation 2 5 NI DAQ User Manual for PC Compatibles Chapter 2 Fundamentals of Building Windows Applications The following paragraph illustrates declarations of functions For Visual Basic 4 0 or later 32 bit Declare Function GlobalAlloc Lib kernel32 Alias GlobalAlloc ByVal wFlags As Long ByVal dwBytes As Long As Long Declare Function GlobalFree Lib kernel32 Alias GlobalFree ByVal hMem As Long As Long Declare Function GlobalLock Lib kernel32 Alias GlobalLock ByVal hMem As Long As Long Declare Function GlobalReAlloc Lib kernel32 Alias GlobalReAlloc ByVal hMem As Long ByVal dwBytes As Long ByVal wFlags As Long As Lo
124. er Event atrigev ocx e Analog Alarm Event alarmev ocx The NI DAQ installer places all of these ActiveX controls in the NIDAQ subdirectory of your Windows 2000 NT 98 95 directory under the file names shown NI DAQ User Manual for PC Compatibles 3 6 ni com Chapter 3 Software Overview These three ActiveX controls actually call the NI DAQ Config DAQ Event Message Config ATrig Event Message and Config Alarm _Deadband functions Visual Basic applications cannot receive Windows messages but if you use NI DAQ ActiveX controls shown previously in this section your Visual Basic application can receive NI DAQ messages Sy Note You can use the OCXs in Visual Basic version 4 0 32 bit or later General DAQ Event You use the General DAQ Event control to configure and enable a single data acquisition event See the Event Message Functions section earlier in this chapter for a complete description of NI DAQ events Table 3 1 lists the properties for the General DAQ Event control 3 Note An n represents a generic number and is not the same value in every occurrence Table 3 1 General DAQ Event Control Properties Property Allowed Property Values Name GeneralDAQEventn default Board l n default Chanstr See Config DAQ Event Message in the NI DAQ Function Reference Online Help file DAQEvent 0 Acquired or generated n scans 1 Every n scans 2 Completed operation or stopped by error 3 Voltage o
125. es Chapter 3 Software Overview Table 3 13 SCXI 1200 Module Settling Rates Maximum Acquisition Gain Rate Settling Time 1 83 3 kS s 12 us 2 to 50 55 kS s 18 us 100 25 kS s 40 us The SCXI 1200 module acquisition rate is limited by the rate at which your PC can service interrupts from the parallel port This is a machine dependent rate The filter setting on the SCXI 1100 and the SCXI 1122 dramatically affects settling time See the Specifications appendix in your SCXI module user manual for details Sy Note The SCXI 1122 uses relays to switch the input channels the module requires 10 ms to settle when the relays switch so the sampling rate in a channel scanning operation cannot exceed 100 Hz If you want to take many readings from each channel and average them to reduce noise you should use the single channel or software scanning method shown in Figure 3 45 instead of the channel scanning method shown in Figure 3 46 This means you select one channel on the module acquire many samples on that channel using the DAQ functions select the next channel and so on This increases the lifetime of your module relays When you have selected a particular channel you can use the fastest sample rate your DAQ device supports with the DAQ functions Analog Output Applications Using the SCXI 1124 analog output module with the NI DAQ functions is simple Call the SCxI_AO Write function to write the voltages you want t
126. es tables 3 49 to 3 50 DIG_Block_Check function 3 58 DIG_Block_Clear function 3 58 DIG_Block_In function 3 58 DIG_Block_Out function 3 58 DIG_Block_PG_Config function 3 58 DIG_Change_Message_Config function 3 60 DIG_Change_Message_Control function 3 60 DIG_DB_Config function 3 59 4 10 DIG_DB_HalfReady function 3 59 4 12 DIG_DB_ Transfer function 3 59 4 11 DIG_Filter_Config function 3 60 DIG_Grp_Config function 3 58 DIG_Grp_Mode function 3 58 DIG_Grp_Status function 3 58 DIG_In_Grp function 3 58 DIG_In_Line function 3 57 DIG_In_ Prt function 3 57 digital I O application tips 3 62 to 3 76 digital change detection with 652X devices 3 60 with 653X devices 3 61 to 3 62 NI DAQ User Manual for PC Compatibles Index digital change notification with 652X devices 3 60 digital double buffered group block T O 3 71 to 3 73 digital group block I O 3 69 to 3 70 digital group I O 3 67 to 3 68 digital line I O 3 65 to 3 66 digital port I O applications 3 63 to 3 65 double buffered I O 3 75 to 3 76 handshaking versus no handshaking digital I O 3 63 pattern generation I O with DIO 32F DIO 653X PCI 6115 and PCI 6120 devices 3 74 to 3 75 SCXI applications 3 127 digital I O functions 3 52 to 3 60 byte mapping to digital I O lines table 3 53 to 3 54 DIG_In_Line 3 57 DIG_In_Prt 3 57 digital change notification functions 3 60 digital filtering function 3 60 DIG_Line_Config 3 57 DIG_
127. escaccevsteaesxceosdeden ceeds E a SS 4 7 Double Buffered Functions ccccccsscccccessscccccessssseeceesssseeeccessssseeceesesssseeeeeesseeeeeees 4 9 Double Buffer Configuration Functions 000 0 eee eeeeseeeeeeeeneeeseeseeneeeseenaes 4 10 Double Buffer Transfer Functions ccccccccecssssccceeessseeeceesesnseecceesssseeeeeens 4 10 Double Buffer HalfReady Functions 20 0 0 ceeeesceeeseceseceseeceeeeseeeneeceeeeseeesase 4 11 COmCIUSION ASEE EE A E AET E S EE Pranddndae EEEE TS 4 12 Chapter 5 Transducer Conversion Functions F cton DestriptohSe serie sie aa a i a ae eia 5 2 RTD_Convert and RTD_Buf_Convett oeoeessssssseseeeseerrerrrrrrsrssssssssessrrrrerere 5 2 Parameter Discussion inkiser naa 5 2 Using This Function sisa nanena e a ea 5 3 Strain_Convert and Strain_Buf_Convert sesesessseeereeererererssseseersrrrrrreeeeeeees 5 4 Parameter DISCUSSION nap r A ee E T RRT 5 4 Using This FUNCHON A raies E R EE EE ES 5 5 Thermistor _Convert and Thermistor_Buf_Convetft cccccsesssssessseceseseeees 5 7 Parameter DiSCUSSION ires hentad pirr ai 5 7 Using This F nctoi seri esea e a eat BRAG Gee 5 8 Thermocouple_Convert and Thermocouple_Buf_Convert cei ceeeeeeeeeees 5 9 Parameter DiSCUSSION cccccsssssccccessssecccecesscccecsesssaeeeecessnaneeeees 5 9 Usine This BUNCH OM assen a a e 5 10 Appendix A Technical Support Resources Glossary Index NI DAQ User Manual for PC Compatibles
128. eseeneeeaesneeeaeenaes 3 55 PCI 6115 and PCI 6120 Device Groups eesssessereseerseesresrsresreersresrrsrsrrsrseese 3 56 Digital VO Finctions y noi e a E tee dae sae 3 57 Group Digital I O Functions 0 eee eee eceeseesceeseeseeeseeeeeeseceeeeaesseeeaeeseeeaeeaeees 3 58 Double Buffered Digital I O Functions 0 0 eseeeceeseeeeeeseeneeeseeneeaes 3 59 Digital Change Notification Functions 0 cc cece essescssesesessessesseseesseneeaes 3 60 Digital Filtering FUNCtion nn eee ni a SS 3 60 Digital Change Notification Applications with 652X Devices 3 60 Digital Change Detection Applications with 653X Devices 3 61 NI DAQ User Manual for PC Compatibles vi ni com Contents Digital I O Application Tips eee eee ese ceeceseceeeeseeeeeseceeeesessesesesseseaeesees 3 62 Handshaking Versus No Handshaking Digital I O 3 63 Digital Port I O Applications eee eeeseeeeeseeeeeesecneeeseeseenseesees 3 63 Digital Line I O Applications eee eseeeeseceeeeseeseceseceeeeaeeeeeaesneseaeesees 3 65 Digital Group I O Applications sessseessseessesesssreetsesrertsreersresrresrnsrsresrsresese 3 67 Digital Group Block I O Applications essessseesseeesseressrsrrersrrsrrsrsrrsrsrrsreseseee 3 69 Digital Double Buffered Group Block I O Applications 0 eee 3 71 Pattern Generation I O with the DIO 32F 653X PCI 6115 and PCI 6120 Devices sesessesssesssesssesrseesrrersresrrsrsresrssesresrsrrsreet 3 74 Dou b
129. etailed call sequences for different types of SCXI operations In effect each of the remaining flowcharts in this section is an enlargement of the Analog Input Operations the Analog Output Operations or the Digital Operations node in Figure 3 41 Please refer to the function descriptions in the NI DAQ Function Reference Online Help file for detailed information about each function used in the flowcharts You can divide the SCXI analog input applications further into two categories single channel applications and channel scanning NI DAQ User Manual for PC Compatibles 3 112 ni com Chapter 3 Software Overview applications The distinction between the two categories is simple single channel applications do not involve automatic channel switching by the hardware during an analog input process channel scanning applications do After you have set up the SCXI system single channel applications use the AI or the DAQ class of functions described earlier in this chapter to acquire the input data To acquire data from more than one channel you need multiple AI or DAQ function calls and you might need explicit SCXI function calls to change the selected SCXI channel this specific type of single channel application is called software scanning After you have set up the SCXI system channel scanning applications use the SCAN and Lab_ISCAN classes of functions described earlier in this chapter to acquire the input data Building Analog Inp
130. ew SOURCE Periodic Signal a GATE Known Pulse 2 CTR_EvRead Count Frequency 4 t1 Figure 3 33 Frequency Measurement For 16 bit resolution event counting and pulse width time lapse or frequency measurement you only need one counter Select cont 0 so that you are notified if the counter overflows see the CTR_EvRead and CTR_EvCount function descriptions in the NI DAQ Function Reference Online Help file If cont 1 event counting continues when the counter rolls over and no overflow condition is registered cont 1 is useful when more than one counter is concatenated for event counting You can use any gating mode In addition select TC toggled output type and positive output polarity during the CTR_Config call so that overflow detection works properly For greater than 16 bit resolution you can concatenate two or more counters Configure a low order counter to count the incoming edges or to measure the incoming pulse Connect the OUT signal of the low order counter to the SOURCE input of the next high order counter by specifying a timebase of 0 for the next high order counter Configure the next high order counter to count once every time the low order counter rolls over You can connect the OUT signal of the next high order counter to the SOURCE input of an additional counter The last counter referred to as the high order counter will perform overflow detection The lower order counters increment co
131. f the timebase frequency is too low the counter can only count a few source edges However if the timebase frequency is too high the counter counts too many source edges causing counter overflow In case of counter overflow a small count typically 1 or 2 is saved on the Hold Register and the counter reloads itself with a zero and waits for a new gate trigger to make a new measurement For a pulse width measurement you use the same NI DAQ calls used for period measurement except that you should set gateMode to high level or low level gating 1 or 2 With high level gating a counter can measure the duration of a positive pulse With low level gating a counter can measure the duration of a negative pulse After you call CTR_ Period the counter starts counting after the gate becomes active When the gate becomes NI DAQ User Manual for PC Compatibles 3 90 ni com Chapter 3 Software Overview inactive the counter value latches to the Hold Register You then can call CTR_EvRead to retrieve the saved value Pulse width is then equal to the value returned by CTR_EvRead timebase When the counter value is latched to the Hold Register the counter reloads itself with a zero and waits for the gate to go active to begin a new measurement For measuring pulse width you need a rough estimate of the duration of the pulse being measured When you configure a counter to measure pulse width the counter continues counting in case of overflow No
132. fail to execute programming instructions due to defects in materials and workmanship for a period of 90 days from date of shipment as evidenced by receipts or other documentation National Instruments will at its option repair or replace software media that do not execute programming instructions if National Instruments receives notice of such defects during the warranty period National Instruments does not warrant that the operation of the software shall be uninterrupted or error free A Return Material Authorization RMA number must be obtained from the factory and clearly marked on the outside of the package before any equipment will be accepted for warranty work National Instruments will pay the shipping costs of returning to the owner parts which are covered by warranty National Instruments believes that the information in this document is accurate The document has been carefully reviewed for technical accuracy In the event that technical or typographical errors exist National Instruments reserves the right to make changes to subsequent editions of this document without prior notice to holders of this edition The reader should consult National Instruments if errors are suspected In no event shall National Instruments be liable for any damages arising out of or related to this document or the information contained in it EXCEPT AS SPECIFIED HEREIN NATIONAL INSTRUMENTS MAKES NO WARRANTIES EXPRESS OR IMPLIED AND SPECIFICALLY DISCLAIMS
133. fer and specify iterations Va WFM Load y Convert output rate to timebase and interval 7 WFM_Rate y Set the update and delay rates WFM_ClockRate Start background waveform generation WFM Group Control operation START Should you pause waveform generation Yes Pause wave Pause the waveform generator WFM Group Control No Start waveform ti m PAUSE generation operation where it was paused Resume waveform generation No Resume wave VEM Group eo y Yes Clear waveform operation RESUME WFM_ Group Control operation CLEAR Figure 3 16 Waveform Generation with Pauses NI DAQ User Manual for PC Compatibles 3 46 ni com Chapter 3 Software Overview Double Buffered Waveform Generation Applications You also can configure waveform generation as a double buffered operation Double buffered operations can perform continuous waveform generation with a limited amount of memory For an explanation of double buffering refer to Chapter 4 NI DAQ Double Buffering Figure 3 17 outlines the basic steps for double buffered waveform applications First enable double buffering by calling WFM_DB_ Config as shown in the first step of Figure 3 17 Although every step is not in the diagram you might also call WFM_ Rate and or WFM_Scale as described in the basic waveform application outline There are two ways in which your application can start waveform g
134. files for example rc def that you have created for graphical user interface GUI applications Specify the directory which contains the NI DAQ header files under the preprocessor include directory settings in your compiler For Visual C 4 X this is under Build Settings C C For Visual C 5 0 6 0 this is under Project Settings C C The NI DAQ header files are located in the Include directory under your NI DAQ directory Add the NI DAQ import library nidag32 1ib to the project The NI DAQ import library files are located in the Lib directory under your NI DAQ directory Build your application You can find some example programs and project files in Examples Visualc directory under your NI DAQ directory To load an example program use one of the generic makefiles with the mak extension To load an example project with Visual C 4 X or later select the menu option File Open Project Workspace and select List Files of Type to be Makefiles Then select the mak file of your choice NI DAQ User Manual for PC Compatibles 2 2 ni com Chapter 2 Fundamentals of Building Windows Applications Refer to the NI DAQ Examples Help Start Programs National Instruments DAQ NI DAQ Examples Help for additional information regarding NI DAQ examples Special Considerations Buffer Allocation To allocate memory you can use the Windows API function GlobalAlloc After allocation lock memory with GlobalLock
135. ger one device from another device share clocks and signals between devices and synchronize devices to the same signals The RTSI bus also can connect signals on a single device To specify the signals on each device that you can connect to the RTSI bus trigger lines each device signal is assigned a signal code number Make all references to that signal by using the signal code number in the RTSI bus trigger function calls The signal codes for each device that can use the RTSI bus trigger lines are outlined later in this section Each signal listed in this chapter also has a signal direction If a signal is listed with a source direction that signal can drive the trigger lines If a signal is listed with a receiver direction that signal must be received from the trigger lines A bidirectional signal direction means that the signal can act as either a source or a receiver depending on the application E Series DSA 660X and 671X RTS Connections For information regarding signals on the E Series DSA 660X and 671X devices that you can connect to the RTSI bus refer to the Select_Signal function description in the NI DAQ Function Reference Online Help file 3 Note Ifyou have a PXI DSA board in slot 2 star trigger controller slot do not drive any signals on RTSI 6 from other modules in the chassis You can use other RTSI lines National Instruments Corporation 3 103 NI DAQ User Manual for PC Compatibles Chapter 3 Software Overv
136. gnal Specify the pulse delay Translate the actual trigger time into the number of seconds since the beginning of the current year x seconds Read the clock value y seconds Specify pulse delay x y Specify the appropriate trigger pulse width Arm the counter Read the clock value If the clock value is still y seconds you are done Ifthe clock value is more than y seconds reset the counter and return to the beginning of step 2 3 101 NI DAQ User Manual for PC Compatibles Chapter 3 Software Overview e Configure analog input analog output operation to trigger upon receiving a pulse on the counter output e Counter produces a pulse when the clock value reaches the desired time interval 3 Poll the armed attribute of the counter until it is disarmed when the counter has generated the trigger pulse 4 At the end of the operation free up any hardware and software resources After powering up the clock will run until the power to the TIO ASIC is turned off RTS Bus Trigger Functions RTS Bus The Real Time System Integration RTSD Bus Trigger functions connect and disconnect signals over the RTSI bus trigger lines Refer to the NI DAQ Function Reference Online Help file to determine which functions your device supports RTSI_Clear Disconnects all RTSI bus trigger lines from signals on the specified device RTSI_Clock Connects or disconnects the system clock from the RTSI bus R
137. gure 3 85 time lapse measurement 3 87 timer event counting figure 3 86 utility functions 3 84 counter timer functions 3 76 to 3 78 See also counter timer application tips counter timer operation CTR_Config 3 77 CTR_EvCount 3 77 CTR_EvRead 3 77 CTR_FOUT_Config 3 77 CTR_Period 3 77 CTR_Pulse 3 77 CTR_Rate 3 77 CTR_Reset 3 77 CTR_Restart 3 77 CTR_Simul_Op 3 77 CTR_Square 3 77 CTR_State 3 78 CTR_Stop 3 78 device support table 3 76 general purpose counter timer functions application tips 3 94 to 3 95 GPCTR_Change_Parameter 3 93 4 10 GPCTR_Config_Buffer 3 93 GPCTR_Control 3 93 GPCTR_Read_Buffer 3 93 4 11 4 12 NI DAQ User Manual for PC Compatibles Index GPCTR_Set_Application 3 93 GPCTR_Watch 3 93 interval counter timer functions application tips 3 92 ICTR_Read 3 91 ICTR_Reset 3 91 ICTR_Setup 3 91 interval counter timer block diagram 3 92 counter timer operation See also interval counter timer functions interval counter timer operation Am9513 based devices gating modes 3 79 timebases 3 78 clocks or time counters 3 95 to 3 102 clock accuracy 3 98 clock resolution 3 95 clock synchronization 3 96 to 3 97 example clock in measurement system 3 98 to 3 99 IRIG Inter Range Instrumentation Group protocols 3 97 to 3 98 pulse per second 3 96 to 3 97 sample code for setting up clock using PPS 3 96 to 3 97 sample use cases 3 99 to 3 102 CTR function operation 3 78 to 3 81
138. he RS 232 port request The smallest signal increment that can be detected by a measurement system Resolution can be expressed in bits in proportions or in percent of full scale For example a system has 12 bit resolution one part in 4 096 resolution and 0 0244 of full scale read only memory Real time clock A clock capable of recording the exact time of events that counts time in days hours minutes seconds and fractions of seconds NI DAQ User Manual for PC Compatibles Glossary RTD RTSI S s S Sample and Hold S H SCXI SDK self calibrating Single Ended SE Inputs slave software trigger stage STC synchronous Resistive Temperature Detector A metallic probe that measures temperature based upon its coefficient of resistivity Real Time System Integration bus The National Instruments timing bus that connects DAQ devices directly by means of connectors on top of the boards for precise synchronization of functions samples per second used to express the rate at which a DAQ device samples an analog signal seconds samples a circuit that acquires and stores an analog voltage on a capacitor for a short period of time Signal Conditioning eXtensions for Instrumentation the National Instruments product line for conditioning low level signals within an external chassis near sensors Software Development Kit a property of a DAQ device that has an extremely stable onboard referen
139. he coordination scheme is simple NI DAQ copies data from a transfer buffer you create to the circular buffer in sequential halves The data in the transfer buffer can be updated between transfers Figure 4 4 illustrates a series of sequential data transfers Outgoing Device Data T Circular Buffer E Transfer Buffer AN at Data Ready Successfully Empty Bust for Output Output Data Figure 4 4 Double Buffered Output with Sequential Data Transfers NI DAQ User Manual for PC Compatibles 4 6 ni com Chapter 4 NI DAQ Double Buffering The double buffered output operation begins when the output device begins outputting data from the first half of the circular buffer Figure 4 4a After the device begins retrieving data from the second half of the circular buffer NI DAQ can copy the prepared data from the transfer buffer to the first half of the circular buffer Figure 4 4b Your application can then update the data in the transfer buffer After the output device is finished with the second half of the circular buffer the device returns to the first half buffer and begins outputting updated data from the first half NI DAQ can now copy the transfer buffer to the second half of the circular buffer Figure 4 4c The data in the transfer buffer is again available for update by your application The process can be repeated endlessly to produce a continuous stream of output data
140. he jumper settings on the device and indicates the update mode of the DACs Use this function if you have changed the jumper settings affecting analog output range and polarity from their factory settings Also use this function to change the analog output settings on devices without jumpers AO Update Updates analog output channels on the specified device to new voltage values when the later internal update mode is enabled by a previous call to AO Configure National Instruments Corporation 3 35 NI DAQ User Manual for PC Compatibles Chapter 3 Software Overview AO VScale AO VWrite AO Write Scales a voltage to a binary value that when written to one of the analog output channels produces the specified voltage Accepts a floating point voltage value scales it to the proper binary number and writes that number to an analog output channel to change the output voltage Writes a binary value to one of the analog output channels changing the voltage produced at the channel Analog Output Application Tips This section contains a basic explanation of how to construct an application using the analog output functions The flowcharts are a quick reference for constructing potential applications from the NI DAQ function calls For most purposes AO_VWrite is the only function required to generate single analog voltages It converts the floating point voltage to binary and writes the value to the device AO_VWrite is the equ
141. hermistor and TempBuf is the return array of temperature values assigned in units determined by TempScale National Instruments Corporation 5 7 NI DAQ User Manual for PC Compatibles Chapter 5 Transducer Conversion Functions Using This Function The following equation expresses the relationship between Volts and R the thermistor resistance see Figure 5 2 Volts Vret Ry Ry R9 Solving the previous equation for R we have R Ry Volts Ves Volts After this function calculates R the function uses the following equation to convert R the thermistor resistance to temperature in Kelvin The function then converts the temperature to the temperature scale you want if necessary T 1 a b n R cn R 43 The values used for a b and c are given below If you are using a thermistor with different values for a b and c consult your thermistor data sheet you can edit the thermistor conversion routine to use your own a b and c values a 1 295361E 3 The following equation expresses the relationship between Volts and R the thermistor resistance see Figure 5 2 Volts Vret Ry Ry R9 Solving the previous equation for R you have R R Volts Vier Volts When you calculate Rj you use the following equation to convert R the thermistor resistance to temperature in Kelvin Then convert the temperature to the temperature scale you want if necessary T 1 a b n R cn R 43
142. ibles Chapter 3 Software Overview Figure 3 22 is a flowchart outlining the basic line I O application TIO DSA 62XX 652X PCI PXI 6703 6704 DIO 6533 DIO 32HS VXI AO 48XDC or E Series device Configure ports for Y Configure lines for input or output Y input or output DIG Line Config DIG Prt_Config a e Y Input data from line Y Output data to line DIG In Line DIG Out_Line No Yes Figure 3 22 Basic Line Input or Output Application First configure the digital lines for input or output You can program 653X devices PC TIO 10 PCI 6703 PCI 6704 PXI 6703 PXI 6704 622XI 671X and E Series devices on an individual line basis To do this call DIG_Line Config You must configure all other devices on a port by port basis As a result you must configure all lines within a port for the same direction Call DIG_Prt_Config to configure a port for input or output For the 652X devices it is not necessary to configure a port or line since the line direction is preconfigured The next step is to callDIG_In_ Line orDIG Out Line to output or input a bit from or to the line The final step is to loop back until NI DAQ has transferred all of the data NI DAQ User Manual for PC Compatibles 3 66 ni com Chapter 3 Software Overview Digital Group 1 0 Applications Digital group I O applications use one or more digital ports as a single group to input or output digital inf
143. ice the module directly connected to the DAQ device must be one of the SSH modules National Instruments Corporation 3 117 NI DAQ User Manual for PC Compatibles Chapter 3 Software Overview Configure each SSH Module in the module scan list for interval scanning SCXI_Track_Hold Setup Specify the module scan list the start channel of each module and the number of channels to scan on each module y SCXI_SCAN Setup Set the gain and or filter settings of each SCXI 1100 SCXI 1102 B C SCXI 1122 SCXI 1125 SCXI 1141 SCXI 1142 SCXI 1143 or y SCXI 1540 module in the module scan list SCXI_Set_Gain and or SCXI Configure_Filter Set up the Mux Counter on the DAQ device so that the total number of samples to be taken in one scan on the DAQ device is equal to y the total number of channels in one scan of the module scan list SCXI M xCtr Setup Acquire the data using the SCAN or Lab_ISCAN functions S H Remember if there are any SSH modules to be scanned y you must use interval scanning Scanned Data Acquisition Have you acquired all the data you need No Yes Disable the Track Hold setup of the SSH modules __ _ s to free the counter resource on the DAQ device y SCXI_Track_Hold_Setup y Figure 3 44 Channel Scanning Operation Using Modules in Multiplexed Mode NI DAQ User Manual for PC Compatibles 3 118 ni com Chapter 3 Software Overview
144. ices See PC LPM 16 LPM16_Calibrate function 3 4 manual See documentation Measurement amp Automation Explorer application 1 7 Microsoft Visual Basic for Windows building Windows applications 2 4 to 2 6 buffer allocation 2 5 to 2 6 example programs 2 5 parameter passing 2 6 procedure 2 4 string passing 2 6 NI DAQ events 3 6 to 3 15 ActiveX controls 3 6 to 3 7 Analog Alarm Event control 3 11 to 3 13 Analog Trigger Event control 3 9 to 3 11 General DAQ Event controls 3 7 to 3 9 General DAQ Event example 3 13 to 3 15 multiple controls 3 13 using multiple controls 3 13 special considerations 2 5 to 2 6 Microsoft Visual C building Windows applications 2 2 to 2 3 example programs 2 2 to 2 3 special considerations 2 3 MIO devices counter usage in waveform generation 3 50 FIFO lag effect 3 51 to 3 52 National Instruments Corporation l 11 Index MIO and AI device terminology table xv xvii reference voltages for waveform generation table 3 49 MIO_Config function 3 4 MIO E series devices See E series devices Multiplexed mode applications SCXI 3 113 to 3 120 multiplexer device AMUX 64T 3 25 multirate scanning flow chart for 3 34 functions for 3 33 purpose and use 3 32 to 3 33 NI 4551 devices counter usage 3 50 FIFO lag effect 3 51 to 3 52 NI Developer Zone A 1 NI DAQ events in Visual Basic for Windows 3 6 to 3 15 ActiveX controls 3 6 to 3 7 Analog Alarm Event control 3
145. ich counter A2 uses for the total update interval The ICTR_Setup and ICTR_Reset functions cannot then use counter BO for the duration of the waveform generation ni com Chapter 3 Software Overview operation In addition the data acquisition functions DAQ Start and Lab_ISCAN Start cannot use counter BO if the total sample interval for data acquisition is also greater than 65 535 us unless the timebase required for data acquisition is the same as the timebase counter BO produces for waveform generation If data acquisition is not in progress counter BO is available for waveform generation if ICTR_Setup has not been called on counter BO since startup or an CTR_Reset call has been made on counter BO If data acquisition is in progress and is using counter BO to produce the sample timebase counter BO is available for waveform generation only if this timebase is the same as required by the Waveform Generation functions to produce the total update interval In this case counter BO produces the same timebase for data acquisition and waveform generation On the AT AO 6 10 counter 0 produces the total update interval for group waveform generation and counter produces the total update interval for group 2 waveform generation However if the total update interval is greater than 65 535 us for either group or 2 counter 2 is used by counter 0 group 1 or counter group 2 to produce the total update interval If either group is using coun
146. ied in 5 V 5 V for PCI and NI 4551 for PCI devices use signed 18 bit binary data a 32 bit word Their output voltage range is 10 V Minimum Update Intervals The rate at which a device can output analog data is limited by the performance of the host computer For waveform generation the limitation is in terms of minimum update intervals The update interval is the period of time between outputting new voltages Therefore the minimum update interval specifies the smallest possible time delay between outputting new data points In other words the minimum update interval specifies the fastest rate at which a device can output data Refer to Chapter 4 NI DAQ Double Buffering for more information on the minimum update intervals Counter Usage NI 4451 for PCI and NI 4551 for PCI devices use the same counter for both waveform generation and analog input data acquisition See WFM_Set_Clock in the NI DAQ Function Reference Online Help file for an explanation of the restrictions this causes This counter is separate from the general purpose counters The MIO 671X 622X1 and E Series devices use dedicated counters from the DAQ STC chip for waveform generation control and timing On the Lab and 1200 devices and analog output devices counter A2 produces the total update interval for waveform generation However if the total update interval is greater than 65 535 us counter BO generates the clock for a slower timebase wh
147. ies your application when a user specified DAQ event occurs Using event messaging eliminates continuous polling of data acquisition processes Config Alarm Deadband Specify alarm on off condition for data acquisition event messaging Config _ATrig Event Message Specify analog input trigger level and slope for data acquisition event messaging Config _DAQ Event Message Specify analog input analog output digital input or digital output trigger condition for event messaging Event Messaging Application Tips To receive notification from the NI DAQ data acquisition process in case of special events you can call Config Alarm _Deadband Config _ATrig_ Event_Message or Config DAQ Event Message to specify an event in which you are interested If you are interested in more than one event you can call any of those three functions again for each event After you have configured all event messages you can begin your data acquisition by calling SCAN Start DIG Block_In and so on When any of the events you specified occur NI DAQ notifies your application Event notification can be done through user defined callbacks and or the Windows Message queue When a user specified event occurs NI DAQ calls the user defined callback if defined and or puts a message into the Windows Message queue if you specified a window handle Your application receives the message when it calls the Windows GetMessage API National Instruments Corpor
148. iew AT AO 6 10 RTSI Connections The AT AO 6 10 contains six signals that you can connect to the RTSI bus trigger lines Table 3 9 shows these signals Table 3 9 AT AO 6 10 RTSI Bus Signals Signal Name Signal Direction Signal Code OUTO Source 0 GATE2 Receiver 1 EXTUPD Source 2 OUT2 Source 3 OUTI1 Source 4 EXTUPDATE Bidirectional 5 The signals GATE2 OUTO OUT1 and OUT2 are input and output signals from the MSM82C53 Counter Timer on the AT AO 6 10 device OUTO OUT1 and OUT2 are outputs of counters 0 1 and 2 respectively GATE2 is the gating signal for counter 2 The signals EXTUPDATE and EXTUPD externally update selected DACs The EXTUPDATE signal is shared with the I O connector For more information about the AT AO 6 10 signals see your device user manual DIO 32F RTS Connections The DIO 32F contains four signals that you can connect to the RTSI bus trigger lines Table 3 10 shows these signals Table 3 10 DIO 32F RTS Bus Signals Signal Name Signal Direction Signal Code REQI Receiver 0 REQ2 Receiver 1 ACK1 Source 2 ACK2 Source 3 NI DAQ User Manual for PC Compatibles 3 104 ni com Chapter 3 Software Overview The signals REQ and REQ are request signals received from the I O connector An external device drives these signals during handshaking ACK1 and ACK2 are supplied for handshaking with the DIO 32F over the RTSI bus Fo
149. if partial transfers of half buffers are enabled Counter Timer Function Group The Counter Timer function group contains three sets of functions the General Purpose Counter Timer GPCTR functions the Interval Counter Timer ICTR functions and the Counter Timer CTR functions These sets of functions perform a variety of timing I O and counter operations such as event counting period and frequency measurement and single pulse and pulse train generation See your hardware user manual to find out which operations are supported by your device Table 3 8 shows the sets of functions according to the devices they support B Note For TIO based 45XX DSA devices use only counters 0 and 1 Refer to the NI DAQ Function Reference Online Help or the device user manual for counter pinouts Table 3 8 Devices Supported by the GPCTR ICTR and CTR Functions 516 Devices E Series 622X11 660X DAQCard 500 700 Lab and Functional Set 671X and DSA Devices 1200 Devices LPM Devices PC TIO 10 GPCTR yes no no ICTR no yes no CTR no no yes NI DAQ User Manual for PC Compatibles 3 76 ni com Counter Timer Functions Chapter 3 Software Overview The Counter Timer CTR functions perform counting timing I O and timing counter operations on the Am9513 based MIO devices and the PC TIO 10 CTR_Config CTR_EvCount CTR_EvRead CTR_FOUT_Config CTR Period CTR_Pulse CTR_Rate CTR_Reset CTR_Restart
150. igned ports to a group the group acts as a single entity controlling 8 16 or 32 digital lines simultaneously The DIO 32F has National Instruments Corporation 3 55 NI DAQ User Manual for PC Compatibles Chapter 3 Software Overview certain restrictions on which ports can be assigned to which groups Refer to Table 3 7 for details Table 3 7 Legal Group Assignments for DIO 32F Devices Assigned Group Group Size Ports Name in Bits and Ports Port 0 1 8 bit group one port Port 1 1 8 bit group one port Port 2 2 8 bit group one port Port 3 2 8 bit group one port Ports 0 and 1 1 16 bit group two ports Ports 2 and 3 2 16 bit group two ports Ports 0 1 2 and 3 1 32 bit group four ports After you assign ports to a group the group controls handshaking of that port These ports are then read from or written to simultaneously by writing or reading 8 or 16 bits at one time from the group You can configure the groups for various handshake configurations The configuration choices include a handshaking protocol inverted or non inverted ACK and REQ lines and a programmed transfer settling time Sy Note Implement buffered digital I O via the DIG_Block functions described in detail in the NI DAQ Function Reference Online Help file PCI 6115 and PCI 6120 Device Groups On the PCI 6115 and PCI 6120 devices port 0 can be broken into two smaller groups These groups are referred to as group an
151. ily halts or restarts waveform generation for a single analog output channel WFM_ Check Returns status information concerning a waveform generation operation WFM_ClockRate Sets an update rate and a delay rate for a group of analog output channels National Instruments Corporation 3 39 NI DAQ User Manual for PC Compatibles Chapter 3 Software Overview WFM_DB Config WFM DB HalfReady WFM_DB Transfer WFM_Group_ Control WFM_Group_Setup WFM_Load WFM Rate NI DAQ User Manual for PC Compatibles 3 40 Enables and disables the double buffered mode of waveform generation Checks if the next half buffer for one or more channels is available for new data during a double buffered waveform generation operation You can use WFM DB HalfReady to avoid the waiting period possible with the double buffered transfer functions Transfers new data into one or more waveform buffers selected in WFM_Load as waveform generation is in progress WFM_DB Transfer waits until NI DAQ can transfer the data from the buffer to the waveform buffer Controls waveform generation for a group of analog output channels Assigns one or more analog output channels to a waveform generation group A call to WFM_Group_ Setup is required only for the AT AO 6 10 By default all analog output channels for the Lab and 1200 analog output 671X devices and MIO devices are in group 1 Assigns a waveform buffer to one or more analog output channel
152. ion application tips analog input functions See data acquisition functions one shot analog input functions analog output application tips 3 36 to 3 38 equivalent analog output calls figure 3 36 SCXI applications 3 126 simple application 3 37 software update application 3 37 to 3 38 analog output devices reference voltages for tables 3 49 to 3 50 analog output functions 3 35 to 3 36 See also waveform generation functions AO_Change_Parameter 3 35 AO_Configure 3 35 AO_Update 3 35 NI DAQ User Manual for PC Compatibles Index AO_VScale 3 36 AO_VWrite 3 36 AO_ Write 3 36 Analog Trigger Event control 3 9 to 3 11 properties table 3 9 to 3 10 setting properties 3 10 to 3 11 AO_ Calibrate function 3 3 AO_Change_Parameter function 3 35 AO_Configure function 3 35 AO_Update function 3 35 AO_VScale function 3 36 AO_VWrite function 3 36 AO_ Write function 3 36 applications for Windows See building Windows applications AT AO 6 10 counter usage in waveform generation 3 51 FIFO lag effect 3 51 to 3 52 reference voltages for waveform generation tables 3 50 RTSI bus connections 3 104 AT DIO 32F See DIO 32F AT MIO 16DE 10 groups of ports 3 55 Borland C Windows applications 2 7 to 2 8 Borland Delphi 2 8 buffer allocation in Windows applications Microsoft Visual Basic 2 5 to 2 6 Microsoft Visual C 2 3 building Windows applications 2 1 to 2 10 Borland C 2 7 to 2 8 Microsoft
153. ion of the acquired data With the double buffered functions you can retrieve half of the data buffer at a time Double buffered functions are very useful when your application has a real time strip chart displaying the incoming data Building Block 4 Cleaning up The purpose of this building block is to stop the data acquisition and free any system resources such as DMA channels used for the data acquisition DAQ_ Clear is the only function needed for this building block and is automatically called by the check functions described in the previous building block when the data acquisition is complete Therefore you can eliminate this last building block if your application continuously calls the previously described check functions until the data acquisition is complete Ss Note DAQ Clear does not alter the device configurations made by building block 1 Double Buffered Data Acquisition The double buffered DAQ_DB data acquisition functions return data from an ongoing data acquisition without interrupting the acquisition These functions use a double or circular buffering scheme that permits half buffers of data to be retrieved and processed as the data becomes available By using a circular buffer you can collect an unlimited amount of data without needing an unlimited amount of memory Double buffered data acquisition is useful for applications such as streaming data to disk and real time data display Initiating double buffered dat
154. itation voltage in volts that you used If the value of Vex is 0 a default excitation voltage of 3 333 V is assumed The SCXI 1121 module provides excitation voltages of 10 V and 3 333 V The SCXI 1122 module provides an excitation voltage of 3 333 V GF is the gauge factor of the strain gauge v is Poisson s Ratio needed only in certain bridge configurations Rg is the strain gauge nominal value in ohms RL is the lead resistance in ohms In many cases the lead resistance is negligible and you can pass a value of 0 for RL to the routine Otherwise you can measure RL to be more accurate Vinit is the unstrained voltage of the strain gauge in volts after it is mounted in its bridge configuration Read this voltage at the beginning of your application and save it to pass to the strain gauge conversion routines NI DAQ User Manual for PC Compatibles 5 4 ni com Chapter 5 Transducer Conversion Functions The Strain Convert routine has two remaining parameters strainVolts is the voltage that NI DAQ read from the strain gauge and strainVal is the return strain value The Strain Buf Convert routine has three remaining parameters numPts is the number of voltage points to convert strainVoltBuf is the array that contains the voltages that NI DAQ read from the strain gauge and strainValBuf is the return array that contains the strain values Using This Function The conversion formula used is based solely on the bridge configura
155. ivalent of a call to AO_VScale followed by a call to AO_Write Figure 3 12 illustrates the equivalency Scale floating point voltage to y binary value AO VScale y Output binary voltage to board AO Write y Scale floating point voltage to binary value and output binary voltage to board AO VWrite Figure 3 12 Equivalent Analog Output Calls The following applications are shown using AO_VWrite However substituting the equivalent AO _VScale and AO Write calls will not change the results NI DAQ User Manual for PC Compatibles 3 36 ni com Chapter 3 Software Overview Simple Analog Output Application Figure 3 13 illustrates the basic series of calls for a simple analog output application Account for any changes in the jumper settings Enable external update pulses AO Configure Output voltage to board AO VWrite Done outputting data Figure 3 13 Simple Analog Output Application The call to AO_Configure in Figure 3 13 must be made only if you have changed the jumper settings of an MIO AT AO 6 10 or Lab PC device You also might call AO_Configure to enable external updating of the voltage When you select external update mode voltages written to the device are not output until you apply a pulse to pin 48 EXTUPDATE on the AT AO 6 10 to pin 39 EXTUPDATE on the Lab and 1200 analog output devices or to the selected pin on an E Series devi
156. l that apply to the NI DAQ function groups you will use in your application Chapter 3 contains valuable NI DAQ concepts including flowcharts for NI DAQ applications Look at the internally documented example source code on your distribution media for your application language and environment y Use the the NI DAQ Function Reference Online Help file for specific information about individual NI DAQ functions Figure 1 1 How to Set up Your DAQ System NI DAQ Overview NI DAQ is a library of routines that work with National Instruments DAQ devices NI DAQ helps you overcome difficulties ranging from simple device initialization to advanced high speed data logging The number of services you need for your applications depends on the types of DAQ devices you have and the complexity of your applications National Instruments Corporation 1 3 NI DAQ User Manual for PC Compatibles Chapter 1 Introduction to NI DAQ NI DAQ Hardware Support National Instruments periodically upgrades NI DAQ to add support for new DAQ hardware To ensure that this version of NI DAQ supports your hardware consult Tables 1 1 through 1 5 Table 1 1 NI DAQ Version 6 9 Plug in Device Support for AT PC and NEC Buses AT PC NEC AT AI 16XE 10 Lab PC PC DIO 96 NEC AI 16E 4 AT AO 6 10 Lab PC 1200 PC DIO 96PnP NEC AI 16XE 50 AT DIO 32F Lab PC 1200AI PC LPM 16 NEC MIO 16E 4 AT MIO 16DE 10 PC 516 PC LPM 16PnP NEC MIO 16XE 50 AT
157. lable on the PC TIO 10 SOURCE Counter OUT GATE Figure 3 26 Counter Block Diagram Each counter has a SOURCE input a GATE input and an output labeled OUT The counters can use several timebases for counting operations A counter can use the signal supplied at any of the Am9513 five SOURCE or GATE inputs for counting operations The Am9513 also makes available five internal timebases that any counter can use e I MHz clock 1 us resolution e 100 kHz clock 10 us resolution e 10 kHz clock 100 us resolution e 1 kHz clock 1 ms resolution e 100 Hz clock 10 ms resolution ys Note A 5 MHz internal timebase 200 ns resolution is also available on SOURCE 5 for counters to 5 and SOURCE 10 for counters 6 to 10 on the PC TIO 10 You can also program the counter to use the output of the next lower order counter as a signal source This arrangement is useful for counter concatenation For example you can program counter 2 to count the output of counter 1 thus creating a 32 bit counter NI DAQ User Manual for PC Compatibles 3 78 ni com Chapter 3 Software Overview You can configure a counter to count either falling or rising edges of the selected internal timebase SOURCE input GATE input or next lower order counter signal You can use the counter GATE input to gate counting operations After you software configure a counter for an operation a signal at the GATE input can
158. lculates calibration constants for the particular channel and range or gain using measured voltage binary pairs You can use this function with any SCXI analog input or analog output module The constants can be stored and retrieved from NI DAQ memory or the module EEPROM if your module has an EEPROM The driver uses the calibration constants to scale analog input data more accurately when you use the SCXI_ Scale function and output data when you use SCXI_AO Write Provides a single call calibration for the SCXI 1112 SCXI 1125 SCXI 1520 and SCXI 1540 modules With the SCXI 1112 and SCXI 1125 calling NI DAQ User Manual for PC Compatibles Chapter 3 Software Overview SCXI_Calibrate_ Setup SCXI_Change_Chan SCXI_Configure_ Connection SCXI_Configure Filter NI DAQ User Manual for PC Compatibles 3 108 this function calibrates individual channels However with the SCXI 1540 calling this function calibrates every channel You also use this function to update the actual onboard reference voltage value on the SCXI 1125 EEPROM and to copy calibration constants to the module s default EEPROM load area from another EEPROM area or from NI DAQ memory Grounds the amplifier inputs of an SCXI 1100 SCXI 1101 SCXI 1122 or SCXI 1141 SCXI 1142 or SCXI 1143 so that you can determine the amplifier offset You also can use this function to switch a shunt resistor across your bridge circuit to test the circuit This function
159. le B ffered T O sssri spritsen eeose araoak reana eias iesist 3 75 Counter Timer Function Group 0 cece eecceseeeeseceseeseeseeeseceeceseeseeeaecneeesesseensesseensessees 3 76 Counter Timer F n toS nonnai a R 3 77 Counter Timer Operation for the CTR Functions 3 78 Programmable Frequency Output Operation eee eee 3 81 Counter Timer Application Tips eee eeeeseeseceeceeeeeetseeneeenees 3 82 Interval Counter Timer Functions 000 0 eee seeesesseesseeeceseeseenseesseneeeaeenaes 3 91 Interval Counter Timer Operation for the ICTR Functions 3 92 Interval Counter Timer Application Tips 0 eee eects eeeeeseeeees 3 92 General Purpose Counter Timer Functions eceeeeseessceseeseeeeeeseeeeeeeeeees 3 93 General Purpose Counter Timer Application Tips eee 3 94 Clocks or Time Counters ic ccsceeads cate cetecsensscsteceschsvecidaanssvetuaes aN a aa AnS 3 95 Clock Resolutionssss ccs sociscatescsiescaced eshesh eds errata eaer nise iaa irira Etan 3 95 Clock Synchronization issin aa 3 96 Clock Accuracy piara aaa a RE R a a a 3 98 Example Clock in a Measurement System sseseseeesserrererrersrrerreree 3 98 Sample Use Cases niei apia isis eg ii eioi isossa 3 99 RTSI Bus Trigger Functions ssssesesesesesesresessererseeseserrsrersensrersrernesensreeeseseese 3 102 RPSTEBUS aeei aioa a ERE a E E R ARRS 3 102 E Series DSA 660X and 671X RTSI Connections ccccecccccceessseeeeeeees 3 103 AT AO 6 10 RTSI
160. lear and restart the block operation The second option available only to output groups is the ability to transfer data that is less than half the circular buffer size to the circular buffer This option is useful when long digital data streams are being output but the size of the data stream is not evenly divisible by the size of half of the circular National Instruments Corporation 3 75 NI DAQ User Manual for PC Compatibles Chapter 3 Software Overview buffer This option imposes the restriction that the double buffered digital block output is halted when a partial block of data has been output This means that the data from the first call to DIG_DB_ Transfer with a count less than half the circular buffer size is the last data output by the device Notice however that enabling either of the double buffered digital output options causes an artificial split in the digital block buffer requiring DMA reprogramming at the end of each half buffer For a group that is configured for handshaking such a split means that a pause in data transfer can occur while NI DAQ reprograms the DMA For a group configured for pattern generation this split can cause glitches in the digital input or output pattern time lapses greater than the programmed period during DMA reprogramming Therefore you should enable these options only if necessary Both options can be enabled or disabled by the DIG_DB Config function nye Note EISA chaining is disabled
161. llocated to complete a synchronous function call for a device For counter operations the transfer function takes timeout as one of the parameters so you do need to call Timeout_Config prior to calling the transfer function The transfer functions are as follows e DAQ DB Transfer e WFM DB Transfer e DIG DB Transfer e GPCTR_Read_ Buffer For analog input operations call DAQ DB Transfer after starting a double buffered analog acquisition to perform a double buffered transfer For waveform operations call WFM_DB Transfer after starting a double buffered waveform generation to perform a double buffered transfer For digital block input and output operations call DIG_DB Transfer after starting a double buffered digital operation to perform a double buffered transfer For counter operations call GPCTR_Read_Buffer after starting the operation to transfer a specified portion of the double buffer Double Buffer HalfReady Functions With the Double Buffer HalfReady functions applications can avoid the delay possible when calling the double buffer transfer function When you call either of the transfer functions NI DAQ waits until the transfer to or from the circular buffer can be made that is the DAQ device is operating on the opposite half of the circular buffer The Double Buffer HalfReady functions check if a double buffer transfer can be completed immediately If the call to Double Buffer HalfReady indicates a transfer cannot be
162. llowing cases are examples of applications that can use clocks Use Case 1 The user records the time of n events with software timing precision A user wants to record the time of an external event for example when a key is pressed on a keyboard when a data packet is received by a CAN controller or when a temperature is read from an AI channel The software program flow is as follows 1 National Instruments Corporation Initialize the clock for this application e Specify the synchronization signal type none e Specify the initial DHMS value the default value of DHMS is undefined Read the clock value days hours minutes seconds when the external event happens to determine the time of the event At the end of the operation free up any hardware and software resources After powering up the clock will run until the power to the TIO ASIC is turned off 3 99 NI DAQ User Manual for PC Compatibles Chapter 3 Software Overview Use Case 2 The user records the time of a single event on two physically distributed data acquisition systems with hardware timing precision A user wants to record how a lightning strike at a power grid in city A travels to a grid station in city B The lightning sensors in both cities produce a TTL pulse upon receiving the lightning bolt in city A Another user wants to correlate buffered analog input measurements across distributed data acquisition systems He connects a GPS recei
163. location iomorro eia oen E EK EREE 2 5 Strine Passan a a o e EN ate 2 6 Parameter Passing ooe ar E E A TRA ANA 2 6 Creating a Windows Application Using Borland C sesesseesseessrersresreeesrrerseesreerses 2 7 Developing an NI DAQ Application ssseseeeeeeseeeeeessessessessessessrssessessessrese 2 7 Example PrograS inian e E aE aa eean 2 7 Special Considerations s in revue ein ois dia e e ia aTa EA EE S 2 8 Using Borland Delphi with NI DAQ sesseeeseesssesrsresresrsresrsresrerrsresrsrenreresresresesresrerestse 2 8 NI DAQ Examples norane en iea thats E EA E AE A EEEE 2 9 National Instruments Corporation V NI DAQ User Manual for PC Compatibles Contents Chapter 3 Software Overview Initialization and General Configuration Functions cceseeeeseeeereeeeeeseeeeeeseeeees 3 2 Software Calibration and Device Specific Functions 00 eee eeeceeeeeeeeeeeeeeeeeeeeeaees 3 3 Event Message Functions inyectan n a ees ee ee Siete 3 5 Event Messaging Application Tips ccc ceeeeeceeseeeeeeseeeseeseceeeeseesseeaeeneeeaes 3 5 NI DAQ Events in Visual Basic for Windows cescceeesceseeeeeeceneeeeeeeeaeeeaes 3 6 ActiveX Controls for Visual Basic wo cece eeeeseeseeeeeeeeeeeeseeenees 3 6 General DAQ Event nnne arr es ae ai 3 7 Analog TMs ser Eventa Seo eee e e a a E an 3 9 Analog Alarm Ev nt ssisrsninnaa n o 3 11 Analog Input Function Group eresien e A E R A E 3 15 One Shot Analog Input Functions
164. lock 2 Start NI DAQ has high level and low level start functions The high level start functions are as follows e DAQ Op e SCAN Op MIO AI and DSA devices only e Lab ISCAN Op DAQCard 500 700 516 devices LPM devices and Lab and 1200 devices only e DAQ to Disk e SCAN to Disk MIO AI and DSA devices only e Lab ISCAN_ to Disk DAQCard 500 700 516 devices LPM devices and Lab and 1200 devices only A high level start call initiates data acquisition but does not return to the function caller until the data acquisition is complete For that reason you do not need the next building block Checking when you use high level start functions Scan Multiple Channels Qan zscmn op Is Lab ISCAN to Disk SCAN to Disk Figure 3 5 Buffered Data Acquisition Application Building Block 2 Start The major advantage of the high level start functions is that they are simple A single call can produce a buffer full or a disk full of data However if your application is acquiring data at a very slow rate or is acquiring a lot of data the high level start functions might tie up the computer for a significant amount of time Therefore NI DAQ has some low level or asynchronous start functions that initiate data acquisition and return to the calling program function caller immediately National Instruments Corporation 3 27 NI DAQ User Manual for PC Compatibles Chapter 3 Software
165. lopment environments e LabWindows CVI 5 0 x e Microsoft Visual C 2 x 32 bit or later e Microsoft Visual Basic 4 0 32 bit or later e Borland C 5 0 These examples illustrate how to use NI DAQ functions to perform a single task All examples are devoid of any code to extract values from GUI objects so that you can focus on how the code flow is formed In addition most parameters are hardcoded at the top of the routine so that if you decide to change them you can simply change the assignment The examples correspond to the function flowcharts that you will see in Chapter 3 Software Overview If a task and a flowchart in the following chapter suits your data acquisition needs you should find a corresponding example to get you started Each example consists of the following files e An appropriate project file for the programming language except for Borland C where bat files are included to help build the executable e A single source code file to illustrate the task at hand e A library of NI DAQ example utility functions for buffer creation waveform plotting error checking and implementing a delay 3 Note None of the examples are installed in their executable exe format To run them you first must build them or load them into the IDE for the appropriate programming language The examples are stored in the hierarchy shown below for each language AI Analog Input examples AO Analog Output examples
166. ls 3 50 reference voltages for analog output devices bipolar output polarity table 3 49 to 3 50 unipolar output polarity table 3 49 waveform generation functions 3 39 to 3 41 high level waveform generation functions 3 39 WFM_from_Disk 3 39 WFM_Op 3 39 low level waveform generation functions 3 39 to 3 41 WFM_Chan_ Control 3 39 3 52 WFM_Check 3 39 3 52 WFM_ClockRate 3 39 WFM_DB_Config 3 40 4 10 WEFM_DB_HalfReady 3 40 4 12 WFM_DB _ Transfer 3 40 4 11 WFM_Group_Control 3 40 WFM_Group_Setup 3 40 WFM_Load 3 40 WFM_Rate 3 40 WFM_ Scale 3 41 WFM_Set_Clock 3 41 l 15 WFM_ClockRate function 3 39 WFM_DB_Config function 3 40 4 10 WFM_DB_HalfReady function 3 40 4 12 WFM_DB _ Transfer function 3 40 4 11 WFM_from_Disk function 3 39 WFM_Group_Control function 3 40 WFM_Group_Setup function 3 40 WFM_Load function 3 40 WFM_Op function 3 39 WFM_ Rate function 3 40 WFM_ Scale function 3 41 WFM_ Set_Clock function 3 41 Windows applications building 2 1 to 2 10 Borland C 2 7 to 2 8 Borland Delphi 2 8 Microsoft Visual Basic 2 4 to 2 6 Microsoft Visual C 2 2 to 2 3 NI DAQ examples 2 9 to 2 10 NI DAQ libraries 2 1 Worldwide technical support A 2 NI DAQ User Manual for PC Compatibles
167. m the last dialog box This icon denotes a note which alerts you to important information Refers to the SCXI 1102 SCXI 1102B and SCXI 1102C modules and the VXI SC 1102 VXI SC 1102B and VXI SC 1102C submodules These MIO and AJ devices are listed in Table 1 National Instruments Corporation ix NI DAQ User Manual for PC Compatibles About This Manual 1200 and 1200AIT device 1394 16 bit device 44XX device 45XX device 516 device 6025E device 6052E device 6053E device 61XX device 622XI device 652X device 653X device 660X device 6602 device 671X device AI device bold DAQCard 500 700 Refers to the DAQCard 1200 DAQPad 1200 Lab PC 1200 Lab PC 1200AI PCI 1200 and SCXI 1200 Refers to a high speed external bus that implements the JEEE 1394 serial bus protocol These MIO and AI devices are listed in Table 1 Refers to the NI 4451 for PCI NI 4452 for PCI NI 4454 for PCI and NI 4472 for PXI CompactPCI Refers to the NI 4551 for PCI and NI 4552 for PCI Refers to the DAQCard 516 and PC 516 Refers to the PCI 6025E and PX 6025E Refers to the PCI 6052E PXI 6052E DAQPad 6052E for1394 and DAQPad 6052E for USB Refers to the PCI 6053E and PXI 6053E Refers to the PCI 6110E PCI 6111E PCI 6115 PXI 6115 PCI 6120 and PXI 6120 Refers to the NI 6222 for PCI NI 6222 for PXI and NI 6224 for Ethernet Refers to the PCI 6527 and PXI 6527 Refers to the AT DIO 32HS PCI DIO
168. made your application can do other work and try again later National Instruments Corporation 4 11 NI DAQ User Manual for PC Compatibles Chapter 4 NI DAQ Double Buffering Conclusion The HalfReady functions are as follows DAQ DB HalfReady WFM DB HalfReady e DIG DB HalfReady GPCTR_Read_ Buffer For analog input operations call DAQ DB HalfReady after starting a double buffered analog acquisition but prior to calling DAQ DB Transfer to check the transfer status of the operation For analog output problems call WFM_DB HalfReady after starting a double buffered waveform generation but prior to calling WFM_DB_ Transfer to check the transfer status of the operation For digital block input and output operations call DIG_DB HalfReady after starting a double buffered digital operation but prior to calling DIG DB Transfer to check the transfer status of the operation For counter operations call GPCTR_Read_Buf fer after calling GPCTR_Control with a timeOut of 0 to check the transfer status of the operation Counters actually transfer their data in a continuous manner not a double buffered manner Double buffering is a data acquisition software technique for continuously inputting or outputting large amounts of data with limited available system memory However double buffering might not be practical for high speed input or output applications The throughput of a double buffered operation is typically limited
169. n Reference Online Help file for further details Your application is now ready to start a waveform generation Call WFM Group Control operation START to start the waveform generation in the background WFM_Group_ Control will return to your application after the waveform generation begins The next step in Figure 3 16 is an application decision to pause the waveform generation The application uses a number of conditions for making this decision including status information returned by WFM_Check Pause the waveform generation by calling WFM_Group_Control operation PAUSE PAUSE stops the waveform generation and maintains the current waveform voltage at the channel output NI DAQ User Manual for PC Compatibles 3 44 ni com Chapter 3 Software Overview Resume the waveform generation by calling WFM_Group_Control operation RESUME RESUME restarts the waveform generation at the data point where it was paused The output rate and the data buffer are unchanged The final step is to call WFM_Group_Control operation CLEAR CLEAR performs all the necessary cleanup work after a waveform generation Additionally CLEAR halts any ongoing waveform generation National Instruments Corporation 3 45 NI DAQ User Manual for PC Compatibles Chapter 3 Software Overview y Assign channels to waveform generation group Va WFM_Group_ Setup Yy Convert floating point voltages to binary values fe WFM Scale y Load waveform buf
170. n an analog input channel and returns the unscaled result AI Read_Scan Returns readings for all analog input channels selected by Scan_Setup AI Read VScan Returns readings in volts for analog input channels selected by Scan_Setup AI_Setup Selects the specified analog input channel and gain setting for externally pulsed conversion operations AI VRead Reads an analog input channel initiates an A D conversion on an analog input channel and returns the result scaled to a voltage in units of volts AI _VScale Converts the binary result from an AI_ Read call to the actual input voltage Single Channel Analog Input Application Tips All of the NI DAQ functions described in this section are for nonbuffered single point analog input readings For buffered data acquisition consult the Data Acquisition Functions section later in this chapter Two of the AT functions are related to device configuration If you have changed the device jumper settings from the factory default settings or want to reprogram the E Series devices call AI_Configure at the beginning of your application to inform NI DAQ about the changes Furthermore if you have connected multiplexer devices AMUX 64T to your MIO and AI devices call AI_Mux_Config once at the beginning of your application to inform NI DAQ about the multiplexer devices For most purposes AI_VRead is the only function required to perform single point analog input readings Use AI_Read when
171. n to calibrate the crystal oscillator on your timing I O 660X device Calibrate DSA Use this function to calibrate your DSA device Calibrate _E Series Use this function to calibrate your E Series device or 671X device and to select a set of calibration constants for NI DAQ to use Configure HW Analog Trigger Configures the hardware analog trigger available on your E Series device LPM16_ Calibrate Calibrates the LPM device converter The function calculates the correct offset voltage for the voltage comparator adjusts positive linearity and full scale errors to less than 0 5 LSB each and adjusts zero error to less than 1 LSB MIO Config Turns dithering on and off For the MIO 64 this function also lets you specify whether to use AMUX 64T channels or onboard channels SCXI_ Calibrate Performs a self calibration or internal calibration for certain SCXI modules Select _Signal Selects the source and polarity of certain signals used by the E Series and DSA devices You typically need to use this function to externally control timing to use the RTSI bus or to configure one of the I O connector PFI pins NI DAQ User Manual for PC Compatibles 3 4 ni com Chapter 3 Software Overview Event Message Functions NI DAQ Event Message functions are an efficient way to monitor your background data acquisition processes without dedicating your foreground process for status checking The NI DAQ Event Message dispatcher notif
172. nding temperature is done by using inverse equations that are specified for a given TCType for different subranges These inverse equations have an error tolerance as shown in Table 5 1 All the reference equations and inverse equations used in these routines are from NIST Monograph 175 NI DAQ User Manual for PC Compatibles 5 10 ni com Chapter 5 Transducer Conversion Functions Table 5 1 shows the valid temperature ranges and accuracies for the inverse equations used for each thermocouple type The errors listed in the table refer to the equations only they do not take into consideration the accuracy of the thermocouple itself the SCXI modules or the DAQ device that is used to take the voltage reading Table 5 1 Temperature Error for Thermocouple Inverse Equations Thermocouple Type Temperature Range Error B 250 to 700 C 0 02 to 0 03 C 700 to 1 820 C 0 01 to 0 02 C E 200 to 0 C 0 01 to 0 03 C 0 to 1 000 C 0 02 C J 210 to 0 C 0 05 to 0 03 C 0 to 760 C 0 04 C 760 to 1 200 C 0 04 to 0 03 C K 200 to 0 C 0 02 to 0 04 C 0 to 500 C 0 05 to 0 04 C 500 to 1 372 C 0 05 to 0 06 C N 200 to 0 C 0 02 to 0 03 C 0 to 600 C 0 02 to 0 03 C 600 to 1 300 C 0 04 to 0 02 C R 50 to 250 C 0 02 C 250 to 1 200 C 0 005 C 1 200 to 1 664 5 C 0 0005 to 0 001 C 1 664 5 to 1 768 1 C 0 00
173. ne which functions your device supports DAQ_Op DAQ to Disk Lab ISCAN Op Lab_ISCAN to Disk NI DAQ User Manual for PC Compatibles 3 20 Performs a synchronous single channel data acquisition operation DAQ Op does not return until NI DAQ has acquired all the data or an acquisition error has occurred Performs a synchronous single channel data acquisition operation and saves the acquired data in a disk file DAQ to Disk does not return until NI DAQ has acquired and saved all the data or an acquisition error has occurred Performs a synchronous multiple channel scanned data acquisition operation Lab_ISCAN_Op does not return until NI DAQ has acquired all the data or an acquisition error has occurred Performs a synchronous multiple channel scanned data acquisition operation and simultaneously saves the acquired data in a disk file Lab ISCAN_ to Disk does not return until NI DAQ has acquired all the data and saved all the data or an acquisition error has occurred ni com SCAN_Op SCAN _to_Disk Chapter 3 Software Overview Performs a synchronous multiple channel scanned data acquisition operation SCAN_Op does not return until NI DAQ has acquired all the data or an acquisition error has occurred Performs a synchronous multiple channel scanned data acquisition operation and simultaneously saves the acquired data ina disk file SCAN _to_ Disk does not return until NI DAQ has acquired all the data and save
174. ne of the four following procedures AnalogAlarm_HighAlarmOon e AnalogAlarm_HighAlarmOff AnalogAlarm_LowAlarmOn e AnalogAlarm_LowAlarmoff You can perform necessary event processing within this procedure such as updating a global count variable or toggling digital I O lines The four Analog Alarm procedures are prototyped as follows Sub AnalogAlarmn HighAlarmOn DoneFlag As Integer Scans As Long Sub AnalogAlarmn HighAlarmoff DoneFlag As Integer Scans As Long Sub AnalogAlarmn LowAlarmOn DoneFlag As Integer Scans As Long Sub AnalogAlarmn LowAlarmoff DoneFlag As Integer Scans As Long NI DAQ User Manual for PC Compatibles 3 12 ni com Chapter 3 Software Overview The parameter DoneFlag equals if the acquisition was over when the Analog Alarm Event fired Otherwise it is 0 Scans equals the number of the scan that caused the Analog Alarm Event to fire Using Multiple Controls In general a program might contain any number of General DAQ Event Analog Trigger Event and Analog Alarm Event controls Just like regular Visual Basic controls there are two ways you can place multiple controls on a Visual Basic form e You can create control arrays by copying and pasting a control that already exists on the form Each individual element in the control array is then distinguished by the Index property and the event procedures is an extra parameter Index as Integer The first element has Index 0 the second el
175. nfig y Start block input DIG Block_In y Start block output DIG Block_Out No D Is NI DAQ ready to transfer the next half of the data IG_DB HalfReady Transfer next half of the data to or from the digital data buffer Yes DIG_DB_Transfer Do you wish to transfer more data to or from the digital buffer Yes DIG _ Block_Check No g Any more data to output Output operations only No Clear block operation if DIG_Block_Check did not DIG Block_Clear NI DAQ User Manual for PC Compatibles Figure 3 25 Double Buffered Block Operation 3 72 ni com Chapter 3 Software Overview The first step for an application is to call DIG_Grp_ Config to configure individual ports as a group Although the steps have been left out of the diagram you can alter the handshaking mode and enable pattern generation as shown in Figure 3 24 and explained in the Digital Group Block I O Applications section earlier in this chapter Next enable double buffering by calling DIG_DB_ Config second step of Figure 3 25 To start the digital block input or output call DIG_Block_In or DIG Block Out After the operation has started you can perform unlimited transfers to or from the circular buffer Input operations transfer new data from the digital buffer for storage or processing Output operations transfer new data to the digital buffer for output To transfer
176. ng Declare Function GlobalUnlock Lib kernel32 Alias GlobalUnlock ByVal hMem As Long As Long String Passing In Visual Basic variables of data type String need no special modifications to be passed to NI DAQ for Windows functions Visual Basic automatically appends a null character to the end of a string before passing it by reference because strings cannot be passed by value in Visual Basic to a procedure or function Parameter Passing By default Visual Basic passes parameters by reference Prepend the ByVal keyword if you need to pass by value NI DAQ User Manual for PC Compatibles 2 6 ni com Chapter 2 Fundamentals of Building Windows Applications Creating a Windows Application Using Borland C This section assumes that you will be using the Borland C IDE to manage your code development and that you are familiar with the IDE Developing an NI DAQ Application To develop an NI DAQ application follow these general steps 1 Open an existing or new Borland C project to manage your application code 2 Create files of type c C source code or cpp C source code and add them to the project e Make sure you include the NI DAQ header file nidaq h as such in your source code files include nidaq h e You may also want to include nidaqens h and nidagerr h e Optionally you can include other files for example rc def for GUI applications 3 Specify the directory that contai
177. ng mode DIO 24 6025E AT MIO 16DE 10 DIO 96 and Lab and 1200 Device Groups You can group together any combination of ports 0 1 3 4 6 7 9 and 10 on the DIO 96 ports 0 and 1 on the DIO 24 and Lab and 1200 devices and ports 2 and 3 on the 6025E devices and AT MIO 16DE 10 to make up larger ports For example with the DIO 96 you can program ports 0 3 9 and 10 to make up a 32 bit handshaking port or program all eight ports to make up a 64 bit handshaking port See Digital I O Application Tips later in this chapter and the DIG_SCAN_Setup function description in the NI DAQ Function Reference Online Help file for more details DIO 32F and 653X Device Groups On the DIO 32F and 653X devices you can assign ports 0 through 3 referring to ports DIOA through DIOD to one of two groups for handshaking These groups are referred to as group and group 2 Group 1 uses handshake lines REQ1 and ACK1 Group 2 uses handshake lines REQ2 and ACK2 The group senses the REQ line An active REQ signal is an indication that the group must perform a read or write The group drives the ACK line After the group has performed a read or write it drives the ACK line to its active state Refer to your device user manual for more information on the handshaking signals A group can be 8 16 or 32 bits wide An 8 bit group can be port 0 1 2 or 3 A 16 bit group can be ports 0 and 1 or ports 2 and 3 A 32 bit group is all four ports After you have ass
178. ns NI DAQ User Manual for PC Compatibles 3 60 ni com Chapter 3 Software Overview Digital Change Detection Applications with 653X Devices For change detection on the 653X see the DIG_Block_PG Config function in the function reference For message generation on the 653X and many other devices see the Config DAQ Event Message function in the function reference Enable filtering DIG Filter_Config y Configure Change Notification DIG_Change_Message_Config y Start Change Notification 7 DIG Change Message Control lt lt _ _ _ _ Yy No Yes Stop Change Notification DIG_Change_Message_Control Figure 3 18 Basic Digital Change Notification To configure change notification call DIG_Change_Message_Config With DIG_Change_Message_Config you can configure individual digital lines for rising falling or rising and falling edge detection Call DIG Filter_Config to enable filtering on some or all of the lines The next step is to start change detection messaging by calling the DIG _Change_Message_Control function with the start control code To stop change notification call DIG_Change_Message_Control with the stop control code These steps form the basis of a basic digital change notification application National Instruments Corporation 3 61 NI DAQ User Manual for PC Compatibles Chapter 3 Software Overview Enable filtering DIG Filter Config
179. ns 3 103 to 3 106 653X devices 3 105 to 3 106 AT AO 6 10 3 104 DIO 32F 3 104 to 3 105 E series DSA 660XX and 671X 3 103 RTSI bus trigger functions RTSI_Clear 3 102 RTSI_Clock 3 102 RTSI_Conn 3 102 RTSI_DisConn 3 102 Select_Signal 3 102 S SCAN_Demux function 3 22 SCAN_Op function 3 21 SCAN_Sequence_Demux function 3 22 to 3 23 3 33 SCAN_Sequence_Retrieve function 3 23 3 33 SCAN_Sequence_Setup function 3 23 3 33 SCAN_Setup function 3 23 SCAN_ Start function 3 23 SCAN_to_Disk function 3 21 SCXI application tips 3 112 to 3 124 analog output applications 3 126 data acquisition rates 3 124 to 3 126 National Instruments Corporation l 13 Index digital applications 3 127 general SCXIbus application flowchart 3 112 Multiplexed mode 3 113 to 3 120 Parallel mode 3 120 to 3 124 SCXI 1200 module settling rates table 3 126 settling rates table 3 125 settling times table 3 125 SCXI functions 3 107 to 3 111 SCXI_AO_Write 3 107 SCXI_Cal_Constants 3 107 SCXI_Calibrate 3 107 to 3 108 SCXI_Calibrate_Setup 3 108 SCXI_Change_Chan 3 108 SCXI_Configure_Connection 3 108 SCXI_Configure_Filter 3 108 SCXI_Get_Chassis_Info 3 109 SCXI_Get_Module_Info 3 109 SCXI_Get_State 3 109 SCXI_Get_Status 3 109 SCXI_Load_Config 3 109 SCXI_ModuleID_Read 3 109 SCXI_MuxCtr_Setup 3 110 SCXI_Reset 3 110 SCXI_Scale 3 110 SCXI_SCAN_ Setup 3 110 SCXI_Set_Config 3 110 SCXI_Set_Excitation 3 1
180. ns for initializing and configuring your hardware and software Refer to the NI DAQ Function Reference Online Help file to determine which functions your device supports Align DMA Buffer Get_DAQ Device Info Get_NI_DAQ Version Init DA Brds NI DAQ User Manual for PC Compatibles 3 2 Aligns the data ina DMA buffer to avoid crossing a physical page boundary This function is for use with DMA waveform generation and digital I O pattern generation Retrieves parameters pertaining to the device operation Returns the version number of the NI DAQ library Initializes the hardware and software states of a National Instruments DAQ device to its default state and then returns a numeric device code that corresponds to the type of device initialized Any operation that the device is performing is halted NI DAQ automatically calls this function your application does not have to call it explicitly This function is useful for reinitializing the device hardware for reinitializing the NI DAQ software and for determining which device has been assigned to a particular slot number ni com Set_DAQ Device Info Timeout _Config Chapter 3 Software Overview Selects parameters pertaining to the device operation Establishes a timeout limit that is used by the synchronous functions to ensure that these functions eventually return control to your application Examples of synchronous functions are DAQ Op DAQ DB Transfer and
181. ns the NI DAQ header and import library files under the source directories Include Libary settings of your compiler For Borland C 5 0 this directory is under Options Projects Directories The NI DAQ header files are located in the Include directory under your NI DAQ directory and the import library files are located in the Lib directory under your NI DAQ directory 4 Add the NI DAQ import library nidaq32 1ib to the project Build your application Example Programs You can find some example programs and project files in Examples Borlandc directory under your NI DAQ directory To build an example program run one of the batch files with the bat extension from a DOS prompt You will have to modify the batch file to set one of the environmental variables to point to your Borland C IDE directory If you open one of the batch files with a text editor you will see the following line set BorlandDir e apps bc5 National Instruments Corporation 2 7 NI DAQ User Manual for PC Compatibles Chapter 2 Fundamentals of Building Windows Applications Change the right hand side of the equal sign to indicate your Borland C IDE directory For help on the usage of the batch file type lt batchfile bat gt froma DOS prompt where lt batchfile bat gt is the file name of batch file you want to run for example AlIonePoint bat To create your own example project with Borland C 5 0 or later using the provided example
182. nstalls the source files for these functions in the same directories as the example programs You can cut and paste include or merge these conversion routines into your application source files in order to call the routines in your application National Instruments Corporation 5 1 NI DAQ User Manual for PC Compatibles Chapter 5 Transducer Conversion Functions The conversion routines are included in NI DAQ as source files rather than driver function calls so that you have complete access to the conversion formulas You can edit the conversion formulas or replace them with your own to meet your application s specific accuracy requirements Comments in the conversion source code simplify the process of making only necessary changes A header file for each language convert h for C C convert bas for Visual Basic contains the constant definitions used in the conversion routines Include or merge this header file into your application program The transducer conversion routine descriptions apply to all languages Function Descriptions RTD_Convert and RTD_Buf_Convert These functions convert a voltage or voltage buffer that NI DAQ reads from an RTD into temperature Parameter Discussion The convType integer indicates whether to use the given conversion formula or to use a user defined formula that you have put into the routine 0 The given conversion formula l Use a user defined formula that has been added to the r
183. nt also denotes text that is a placeholder for a word or value that you must supply Refers to the DAQCard 1200 DAQPad 1200 Lab PC Lab PC 1200 PCI 1200 and SCXI 1200 Refers to the DAQCard 1200 DAQPad 1200 Lab PC Lab PC 1200 Lab PC 1200AI PCI 1200 and SCXI 1200 Refers to the PC LPM 16 and PC LPM 16PnP Refers to multifunction I O devices See Table 1 for a list of these devices Refers to the AT MIO 16XE 50 DAQPad MIO 16XE 50 and NEC MIO 16XE 50 and PCI MIO 16XE 50 Refers to the AT MIO 64E 3 PCI 6031E PCI 6071E VXI MIO 64E 1 and VXI MIO 64XE 10 Text in this font denotes text or characters that you should enter from the keyboard sections of code programming examples and syntax examples This font is also used for the proper names of disk drives paths directories programs subprograms subroutines device names functions operations properties methods variables filenames and extensions and code excerpts Bold text in this font denotes the messages and responses that the computer automatically prints to the screen This font also emphasizes lines of code that are different from the other examples NI DAQ User Manual for PC Compatibles About This Manual monospace italic NI DAQ NI TIO based device PC PCI Series PXI remote SCXI SCXI 1102 B C SCXI 1120 D SCXI 1104 C SCXI analog input module SCXI analog output module SCXI chassis SCX digital module SCXI switch modul
184. nterval scanning operation Remember that only the MIO and AI devices Lab PC PCI 1200 SCXI 1200 and DAQCard 1200 devices work with channel scanning using tan SSH module SCXI Data Acquisition Rates The settling time of the SCXI modules can affect the maximum data acquisition rates that your DAQ device can achieve The settling times of the different SCXI modules at each gain setting are listed in Table 3 12 for three different DAQ devices The maximum data acquisition rate you can use will be the inverse of the settling time for your SCXI module and DAQ device For example if the settling time is listed as 7 us your maximum data acquisition rate will be 1 7 us 143 kS s If you are using a DAQ device with a maximum acquisition rate faster than the AT MIO 16E 2 such as the PCI MIO 16E 1 you should use the settling times and corresponding maximum acquisition rates listed for the AT MIO 16E 2 If you are using a DAQ device with a maximum acquisition rate slower than 200 kS s such as the PCI 6032E you should add 1 us to the settling time of your DAQ device The maximum acquisition rate for the PCI 6032E would be 1 10 us 1 us 90 9 kS s If you are using a DAQ device faster than 200 kS s but slower than the AT MIO 16E 2 such as an AT MIO 64E 3 you can interpolate between the settling times listed for these devices to calculate an appropriate settling time and corresponding maximum data acquisition rate NI DAQ User Manual
185. ntinuously and generate output pulses when they roll over NI DAQ User Manual for PC Compatibles 3 88 ni com Chapter 3 Software Overview For 32 bit counting use two counters For 48 bit counting use three counters and so on The counter configurations for concatenated event counting are as follows e Low order counter configuration gateMode cither level gating or no gating edgeMode any value outType TC pulse output type outPolarity positive polarity timebase any value cont 1 continuous counting e Intermediate counter configuration edgeMode count rising edges indicates that the low order counter rolled over gateMode no gating outType TC pulse output type outPolarity positive polarity timebase 0 counts lower order counter output cont 1 continuous counting e High order counter configuration edgeMode count rising edges indicates that the low order counter rolled over gateMode no gating outType TC toggled output type for proper overflow detection outPolarity positive polarity timebase 0 counts lower order counter output cont 0O counter stops on overflow Period and Continuous Pulse Width Measurement Applications With the proper use of CTR_Config CTR_Period and CTR_EvRead you can configure a counter to make period or continuous pulse width measurements To make a period measurement call CTR_Config with gateMode set to either rising or falling edge triggered g
186. o the module DAC channels You can use the SCXI_Get_ Status function to determine when the DAC channels have settled to their final analog output voltages To calculate new calibration constants for SCXI_AO Write to use for the voltage to binary conversion instead of the factory calibration constants that are shipped in the module EEPROM follow the procedure outlined in the SCXI_Cal_Constants function description NI DAQ User Manual for PC Compatibles 3 126 ni com Chapter 3 Software Overview Digital Applications If you configured your digital or relay modules for multiplexed mode use the SCXI_Set_State and SCXI_Get_State functions to access your digital or relay channels If you are using the SCXI 1160 module you might want to use the SCXI_Get_ Status function after calling the SCXI_Set_State function SCXI_Get_Status tells you when the SCXI 1160 relays have finished switching If you are using the SCXI 1162 HV module SCxXI_Get_State reads the module input channels For the other digital and relay modules SCXI_Get_State returns a software copy of the current state that NI DAQ maintains However if you are using the SCXI 1163 R in parallel mode SCXI_Get_State reads the hardware states If you are using the SCXI 1162 HV or SCXI 1163 R in parallel mode you can use the SCXI functions as described above or you can call the DIG In Prt and DIG Out_Prt functions using the correct DAQ device port numbers that correspond to the SCXI mo
187. of your application by selecting a specific parameter setting Assigns the buffer that NI DAQ uses for a buffered counter operation Controls the operation of the general purpose counter Transfers data from the previously assigned buffer during an asynchronous counter operation Selects the application for which you use the general purpose counter The function description in the NI DAQ Function Reference Online Help file contains many application tips Monitors the state of the general purpose counter and its operation NI DAQ User Manual for PC Compatibles Chapter 3 Software Overview General Purpose Counter Timer Application Tips The General Purpose Counter Timer GPCTR functions perform a variety of event counting time measurement and pulse and pulse train generation operations including buffered operations When using the GPCTR functions follow the generic program flow as shown in Figure 3 36 Select Counter Application Program Counter Arm Configure Buffer if needed Change Counter Attributes Read Attributes or Buffer Reset Counter Figure 3 36 Generic Program Flow for All GPCTR Counter Applications To select the type of application you want to use for example simple event counting buffered event counting period measurement and so on call the GPCTR_Set_Application function with the appropriate application parameter If the application is
188. ons However the DIO 24 6025E devices AT MIO 16DE 10 DIO 96 and Lab and 1200 devices have special wiring requirements for groups larger than one port The wiring for both the input and output cases for these devices is explained in the DIG_SCAN Setup function description No additional wiring is necessary for the DIO 32F and 653X devices The first step for a group block I O application is to call DIG_Grp Config or DIG_SCAN Setup to configure individual ports as a group Call DIG Grp Config if you have a DIO 32F 653X PCI 6115 or a PCI 6120 device Call DIG_SCAN_ Setup for all other devices The DIO 32F is restricted to group sizes of two and four ports for block I O If you are using a DIO 32F or 653X device you can alter the handshaking mode of the group by calling DIG_Grp Mode For the DIO 32F 653X PCI 6115 and PCI 6120 you can perform digital pattern generation by calling DIG_Block_PG Config as shown in Figure 3 24 Pattern generation is simply reading in or writing out digital data at a fixed rate This is the digital equivalent of analog waveform generation To enable pattern generation call DIG_Block_ PG Config as shown in Figure 3 24 You cannot handshake with pattern generation so do not connect any handshaking lines Refer to the explanation of pattern generation later in this chapter for more information The next step for your application as illustrated in Figure is to call DIG _Block_In or DIG Block_Out to start the d
189. orm generation functions 3 39 low level waveform generation functions 3 39 to 3 41 ni com G GATE2 signal table 3 104 gated pulse generation 3 83 to 3 84 gating modes Am9513 based devices 3 79 General DAQ Event controls 3 7 to 3 9 examples 3 13 to 3 15 properties table 3 7 to 3 8 setting properties 3 8 to 3 9 general purpose counter timer functions application tips 3 94 to 3 95 GPCTR_Change_Parameter 3 93 4 10 GPCTR_Config_Buffer 3 93 GPCTR_Control 3 93 GPCTR_Read_Buffer 3 93 GPCTR_Set_Application 3 93 GPCTR_Watch 3 93 Get_DAQ_Device_Info function 3 2 Get_NI_DAQ_Version function 3 2 GPCTR_Change_Parameter function 3 93 4 10 GPCTR_Config_Buffer function 3 93 GPCTR_Control function 3 93 GPCTR_Read_Buffer function 3 93 4 11 4 12 GPCTR_Set_Application function 3 93 GPCTR_Watch function 3 93 group digital I O applications digital double buffered group block I O 3 71 to 3 73 digital group block I O 3 69 to 3 70 digital group I O 3 67 to 3 68 group digital I O functions 3 58 to 3 59 DIG_Block_Check 3 58 DIG_Block_Clear 3 58 DIG_Block_In 3 58 DIG_Block_Out 3 58 DIG_Block_PG_Config 3 58 DIG_Grp_Config 3 58 DIG_Grp_Mode 3 58 DIG_Grp_Status 3 58 National Instruments Corporation l 9 Index DIG_In_Grp 3 58 DIG_Out_Grp 3 59 DIG_SCAN_Setup 3 59 DIG_Trigger_Config 3 59 groups of ports DIO 24 6025E AT MIO 16DE 10 DIO 96 and Lab and 1200 series groups
190. ormation except for the PCI 6115 and the PCI 6120 which can create groups smaller than the port size for digital operations Figure 3 23 is a flowchart for group digital applications that input and output data one point at a time Only the DIO 32F and 653X devices can execute group input or output one point at a time y Configure groups for input or output DIG Grp Config y Alter handshaking mode DIG Grp Mode Check if group is ready for transfer Not Ready DIG _Grp_ Status Ready Y Input data from group Y Output data from group DIG In cme _i DIG Out conc Figure 3 23 Simple Digital Group Input or Output Application National Instruments Corporation 3 67 NI DAQ User Manual for PC Compatibles Chapter 3 Software Overview At the start of your application call DIG_Grp_ Config to configure the individual digital ports as a group After the ports are grouped call DIG Grp Mode step 2 of Figure 3 23 to alter the handshaking mode of the DIO 32F and 653X devices The various handshaking modes and the default settings are explained in the DIG_Grp_ Mode function description The next step in your application is to check if the port is ready for a transfer step 3 of Figure 3 23 To do this call DIG_Grp_ Status If the group status indicates it is ready call DIG_Out_Grp or DIG _In Grp to transfer the data to or from the group The final step of the flowch
191. ote Implement buffered analog output using the Waveform Generation wFM functions NI DAQ User Manual for PC Compatibles 3 38 ni com Chapter 3 Software Overview Waveform Generation Functions Use the Waveform Generation WF functions to perform buffered analog output operations with the MIO devices 671X devices AT AO 6 10 devices and Lab and 1200 analog output devices Refer to the NI DAQ Function Reference Online Help file to determine which functions your device supports High Level Waveform Generation Functions The following high level Waveform Generation functions accomplish with a single call tasks that require several low level calls to accomplish WFM_ from Disk Assigns a disk file to one or more analog output channels selects the rate and the number of times the data in the file is to be generated and starts the generation WFM_from_Disk always waits for completion before returning unless you call Timeout_Config WFM_Op Assigns a waveform buffer to one or more analog output channels selects the rate and the number of times the data in the buffer is to be generated and starts the generation If the number of buffer generations is finite WFM_Op waits for completion before returning unless you call Timeout_Config Low Level Waveform Generation Functions Low level Waveform Generation functions are for setting up starting and controlling synchronous waveform generation operations WFM_ Chan Control Temporar
192. outine Tex is the excitation current in amps that was used with the RTD If a 0 is passed in Iex a default excitation current of 150 x 10 A 150 mA is assumed Ro is the RTD resistance in ohms at 0 C A and B are the coefficients of the Callendar Van Diisen equation that fit your RTD The TempScale integer indicates which temperature units you want your return values to be Constant definitions for each temperature scale are given in the conversion header file 1 Celsius 2 Fahrenheit 3 Kelvin 4 Rankine NI DAQ User Manual for PC Compatibles 5 2 ni com Chapter 5 Transducer Conversion Functions The RTD_Convert routine has two remaining parameters RTDVolts is the voltage that NI DAQ read from the RTD and RTDTemp is the return temperature value The RTD Buf Convert routine has three remaining parameters numPts is the number of voltage points to convert RTDVoltBuf is the array that contains the voltages that NI DAQ read from the RTD and RTDTempBuf is the return array that contains the temperatures Using This Function The conversion routines first find the RTD resistance by dividing RTDVolts or each element of RTDVoltBuf by Iex The function converts that resistance to a temperature using a solution to the Callendar Van Diisen equation for RTDs R Roll At Bt C t 100 t For temperatures above 0 C the C coefficient is 0 and the equation reduces to a quadratic equation for which we have found th
193. quired you should see the text box display a completion message If you run into errors refer to the NI DAQ Function Reference Online Help file for guidance 10 Click on the Exit button to stop the program Analog Input Function Group The analog input function group contains two sets of functions the one shot analog input functions which perform single A D conversions and the data acquisition functions which perform multiple clocked buffered A D functions Within the analog input functions single channel analog input AT functions perform single A D conversions on one channel Within the data acquisition functions there are high level low level and low level double buffered functions If you are using SCXI analog input modules other than the SCXI 1200 you must use the SCXI functions first to program the SCXI hardware Then you can use these functions to acquire the data using your DAQ device or SCXI 1200 module National Instruments Corporation 3 15 NI DAQ User Manual for PC Compatibles Chapter 3 Software Overview One Shot Analog Input Functions Single Channel Analog Input Functions Use the single channel Analog Input functions for analog input on the 516 devices DAQCard 700 analog input Lab and 1200 devices MIO and AI devices and LPM devices Refer to the NI DAQ Function Reference Online Help file to determine which functions your device supports AI_ Check Returns the status of the analog input circuit
194. quired to store one byte of data Celsius computing index a method of compensating for inaccuracies in thermocouple circuits A software utility that converts a source program in a high level programming language such as C C Visual Basic version 5 0 or Borland Delphi into an object or compiled program in machine language Compiled programs run 10 to 1 000 times faster than interpreted programs the time required in an analog input or output system from the moment a channel is interrogated such as with a read instruction to the moment that accurate data is available a circuit that counts external pulses or clock pulses timing NI DAQ User Manual for PC Compatibles Glossary coupling CPU D D A DAC DAQ DC DDS device differential input digital port DIN DIO dithering the manner in which a signal is connected from one location to another central processing unit digital to analog D A converter an electronic device often an integrated circuit that converts a digital number into a corresponding analog voltage or current 1 data acquisition collecting and measuring electrical signals from sensors transducers and test probes or fixtures and inputting them to a computer for processing 2 data acquisition collecting and measuring the same kinds of electrical signals with A D and or DIO devices plugged into a computer and possibly generating control signals with D A and or DIO de
195. quisition functions 3 23 to 3 24 digital I O function group 3 52 to 3 60 application tips 3 62 to 3 76 byte mapping to digital I O lines table 3 53 to 3 54 digital I O functions 3 57 to 3 58 digital line I O applications 3 65 to 3 66 DIO 24 6025E AT MIO 16DE 10 DIO 96 and Lab and 1200 series groups 3 55 DIO 32F and 653X groups 3 55 to 3 56 double buffered digital I O functions 3 59 group digital I O functions 3 58 to 3 59 overview 3 52 to 3 55 NI DAQ User Manual for PC Compatibles l 8 event message functions application tips 3 5 to 3 6 list of functions 3 5 NI DAQ events in Visual Basic for Windows 3 6 to 3 15 initialization and general configuration functions 3 2 to 3 3 interval counter timer functions application tips 3 92 interval counter timer operation 3 92 list of functions 3 91 list of function groups 3 1 to 3 2 RTSI bus trigger functions 653X RTSI connections 3 105 to 3 106 application tips 3 106 to 3 107 AT AO 6 10 RTSI connections 3 104 DIO 32F RTSI connections 3 104 to 3 105 E series DSA 660X and 671X RTSI connections 3 103 list of functions 3 102 SCXI functions application tips 3 112 to 3 124 list of functions 3 107 to 3 111 software calibration and device specific functions 3 3 to 3 4 transducer conversion functions function descriptions 5 2 to 5 11 list of functions 5 1 overview 5 1 to 5 2 waveform generation functions application tips 3 41 to 3 52 high level wavef
196. r more information about the DIO 32F signals see the AT DIO 32F User Manual 653X RTSI Connections The 653X devices except for the DAQCard 653X contain eight signals that you can connect to the RTSI bus trigger lines Table 3 11 shows these signals The direction of each signal depends on the function you are performing Some signals have a different direction when you enable pattern generation using DIG_ Block PG Config than when you leave pattern generation disabled Make sure that you do not configure a signal as a RTSI receiver when you use that signal as a device output For example do not configure the 653X device to receive the REQ line from the RTSI bus if you are using internal requests or if you have made an external connection that drives the REQ pin on the I O connector Table 3 11 653X RTSI Bus Signals Signal Direction Signal Direction Handshaking Signal Direction Signal Name Pattern Direction No Pattern Generation No Handshaking Signal Code REQ1 Receiver external Receiver Receiver 0 requests or source internal requests REQ2 Receiver external Receiver Receiver 1 requests or source internal requests ACK1 Receiver Source Source 2 STARTTRIG1 ACK2 Receiver Source Source 3 STARTTRIG2 STOPTRIG1 Receiver Unused Receiver 4 STOPTRIG2 Receiver Unused Receiver 5 PCLK1 Unused Source internal clock or Source 6 receiver external clock PCLK2 Unused Source inte
197. r size to a minimum Note Multirate scanning is a feature that is implemented for all E Series devices except the 61 1X devices Multirate scanning works by scanning each channel at a rate that is a fraction of the specified scan rate For example if you want to scan four channels at 6 000 4 000 3 000 and 1 000 scans per second specify a scan rate of 12 000 scans per second and a scan rate divisor vector of 2 3 4 3 32 ni com Chapter 3 Software Overview NI DAQ includes three functions for multirate scanning e SCAN Sequence _ Setup e SCAN Sequence Retrieve e SCAN Sequence _Demux Use SCAN_Sequence_ Setup to identify the channels to scan their gains and their scan rate divisors After the data is acquired use SCAN Sequence Retrieve and SCAN Sequence _Demux to arrange the data into a more convenient format Figure 3 11 shows how to use the multirate scanning functions in conjunction with other NI DAQ functions National Instruments Corporation 3 33 NI DAQ User Manual for PC Compatibles Chapter 3 Software Overview timebase and sample interval convert scan Convert sampling rate to sample rate to scan timebase and scan interval DAQ Rate Select channels and their gains and scan rate divisors SCAN Sequence Setup Allocate your buffer using the values returned by SCAN Sequence Setup in the scansPerSequence and samplesPerSequence output variables Retrieve the sc
198. r written consent of National Instruments Corporation Trademarks ComponentWorks CVI DAQCard DAQ Designer DAQPad DAQ PnP DAQ STC LabVIEW National Instruments ni com NI DAQ PXI RTSI SCXI and VirtualBench are trademarks of National Instruments Corporation Product and company names mentioned herein are trademarks or trade names of their respective companies WARNING REGARDING USE OF NATIONAL INSTRUMENTS PRODUCTS 1 NATIONAL INSTRUMENTS PRODUCTS ARE NOT DESIGNED WITH COMPONENTS AND TESTING FOR A LEVEL OF RELIABILITY SUITABLE FOR USE IN OR IN CONNECTION WITH SURGICAL IMPLANTS OR AS CRITICAL COMPONENTS IN ANY LIFE SUPPORT SYSTEMS WHOSE FAILURE TO PERFORM CAN REASONABLY BE EXPECTED TO CAUSE SIGNIFICANT INJURY TO A HUMAN 2 IN ANY APPLICATION INCLUDING THE ABOVE RELIABILITY OF OPERATION OF THE SOFTWARE PRODUCTS CAN BE IMPAIRED BY ADVERSE FACTORS INCLUDING BUT NOT LIMITED TO FLUCTUATIONS IN ELECTRICAL POWER SUPPLY COMPUTER HARDWARE MALFUNCTIONS COMPUTER OPERATING SYSTEM SOFTWARE FITNESS FITNESS OF COMPILERS AND DEVELOPMENT SOFTWARE USED TO DEVELOP AN APPLICATION INSTALLATION ERRORS SOFTWARE AND HARDWARE COMPATIBILITY PROBLEMS MALFUNCTIONS OR FAILURES OF ELECTRONIC MONITORING OR CONTROL DEVICES TRANSIENT FAILURES OF ELECTRONIC SYSTEMS HARDWARE AND OR SOFTWARE UNANTICIPATED USES OR MISUSES OR ERRORS ON THE PART OF THE USER OR APPLICATIONS DESIGNER ADVERSE FACTORS SUCH AS THESE AR
199. r you have initialized and reset the SCXI chassis and modules you can use the AI DAQ SCAN or Lab_ISCAN functions with the DAQ device Remember that the channel and gain parameters of the AI DAQ SCAN and Lab_ISCAN functions refer to the DAQ device channels and gains For example to acquire a single reading from channel 0 on the module call the AI_ Read function with the channel parameter set to 0 The gain parameter refers to the DAQ device gain You then can use the SCXI_ Scale function to convert the binary reading to a voltage The AI_VRead function call is not generally useful in SCXI applications because it does not take into account the gain applied at the SCXI module when scaling the binary reading To build a channel scanning application using the SCXI 1120 D SCXI 1121 SCXI 1125 SCXI 1126 SCXI 1141 SCXI 1142 or SCXI 1143 in parallel mode use the SCAN and Lab_ISCAN functions to scan the channels on the DAQ device that correspond to channels on the module you want For example to scan channels 0 1 and 3 on the module using an MIO 16 device call the SCAN_Op function with the channel vector set to 0 1 3 The gain vector should contain the MIO and AI device channel gains After the data is acquired you can demultiplex it and send the data for each channel to the DAQ_VScale function Remember to pass the total gain to the DAQ_VScale function to obtain the voltage read at the module input In many of the data acquisition
200. ransferred Data Figure 4 5 Double Buffered Output with an Overwrite Before Copy For this situation NI DAQ returns an overwrite before a copy warning overWriteError This warning indicates that the device has output old data but the data was uncorrupted during output Subsequent transfers will not return the warning as long as they keep pace with the output device as in Figure 4 4 The second potential problem is when an output device retrieves data that NI DAQ is simultaneously overwriting with data from the transfer buffer NI DAQ returns an overwrite error overWriteError when this occurs The situation is presented in Figure 4 6 NI DAQ User Manual for PC Compatibles 4 8 ni com Chapter 4 NI DAQ Double Buffering Outgoing Device Data anc Circular Buffer i T oa Pai a OY Cae J A b Lv Vi 4 z EA e aoa EE f Pi Overwrite Error Empty Data Ready Successfully Corrupted Buffer for Output Output Data Output Figure 4 6 Double Buffered Output with an Overwrite In Figure 4 6b NI DAQ has started to copy data from the transfer buffer to the first half of the circular buffer However NI DAQ is unable to copy all of the data before the output device begins retrieving data from the first half Figure 4 6c Consequently device data output might be corrupted it might contain both old and new data points Future tr
201. rate into the timebase and sample interval values needed to produce the rate you want Sets the scan rate for a group of channels Initiates an asynchronous single channel data acquisition operation and stores its input in an array Enables the pretrigger mode of data acquisition and indicates the number of data points to acquire after you apply the stop trigger pulse at the appropriate PFI pin Converts the values of an array of acquired binary data and the gain setting for that data to actual input voltages measured Checks if the current scan data acquisition operation begun by the Lab_ISCAN Start function is complete and returns the status the number of samples acquired to that point and the scanning order of the channels in the data array Initiates a multiple channel scanned data acquisition operation and stores its input in an array Rearranges or demultiplexes data acquired by a SCAN operation into row major order that is each row of the array holding the data corresponds to a scanned channel for easier access by C applications SCAN_Demux does not need to be called by BASIC applications to rearrange two dimensional arrays because these arrays are accessed in column major order Rearranges the data produced by a multirate acquisition so that all the data ni com Chapter 3 Software Overview from each channel is stored in adjacent elements of your buffer SCAN Sequence Retrieve Returns the scan s
202. ration 3 13 NI DAQ User Manual for PC Compatibles Chapter 3 Software Overview 2 To place the GeneralDAQEvent control into your form go to the tool box window and select the GeneralDAQEvent tool labelled DAQ EVENT 3 Click somewhere on the form and while holding down the mouse button drag the mouse to place the control onto the form You will see a small icon which does not appear in run time 4 To set up a DAQ Event that notifies you after every n scans DAQ Event 1 unless you decide to make n very large you can use the Set_DAQ Device Info function to set the device analog inputs to use interrupts The constants used in this function come from NIDAQCNS INC See the function description for Set_DAQ Device_Info in the NI DAQ Function Reference Online Help file for more information You must also configure some parameters so that the GeneralDAQEvent can occur when it needs to In the Form_Load event routine add the following to the existing code er Set _DAQ Device Info 1 ND DATA XFER MODE AI ND_INTERRUPTS set AI to use INTR GeneralDAQEvent1 Board 1 assume Device 1 GeneralDAQEvent1 DAQEvent 1 event every N scans GeneralDAQEvent1 DAQTrigValO 1000 set N 1000 scans GeneralDAQEvent1 Enabled True 5 Next start an asynchronous operation Use the NI DAQ function DAQ Start Set up your program so it does a DAQ_ Start on channel 0 when you click on a button you have placed on your form To do so
203. rnal clock or Source 7 receiver external clock National Instruments Corporation 3 105 NI DAQ User Manual for PC Compatibles Chapter 3 Software Overview REQ and REQ are request signals generated internally or received from the I O connector ACK1 and ACK2 are acknowledge signals used for handshaking mode in pattern generation mode they can carry start trigger signals instead PCLK1 and PCLK2 are the peripheral clock lines for burst mode STOPTRIGI and STOPTRIG2 are used for data acquisition timing For more information about the 653X signals refer to the DIO 653X User Manual Find additional explanations of the ACK1 ACK2 STOPTRIGI and STOPTRIG2 signals in the DIG_Trigger_ Config function in the NI DAQ Function Reference Online Help file RTSI Bus Application Tips This section gives a basic explanation of how to construct an application that uses RTSI bus NI DAQ functions Use the flowcharts as a quick reference for constructing potential applications from the NI DAQ function calls An application that uses the RTSI bus has three basic steps 1 Connect the signals from the device to the RTSI bus 2 Execute the work of the application 3 Disconnect the signals from the RTSI bus Figure 3 40 illustrates the normal order of RTSI function calls y Connect clock signals on RTSI bus RTSI_Clock Connect each device signal to a specified RTSI bus trigger line A completed signal path requires two RT
204. roperties Property Allowed Property Values Name GeneralDAQEventn default Board l n default Chanstr See Config DAQ Event Message in the NI DAQ Function Reference Online Help file Level Single voltage WindowSize Single voltage Slope 0 Positive default 1 Negative TrigSkipCount Long PreTrigScans Long PostTrigScans Long National Instruments Corporation 3 9 NI DAQ User Manual for PC Compatibles Chapter 3 Software Overview Table 3 2 Analog Trigger Event Control Properties Continued Property Allowed Property Values Index N A Tag N A Enabled 0 False default 1 True The Analog Trigger Event requires that you set the asynchronous data acquisition operation to use interrupts For more information on Analog Trigger Events refer to the descriptions for the Config ATrig Event Message function in the NI DAQ Function Reference Online Help file Each of these properties should be set as follows AnalogTriggerEventn property name property value For example to set the ChanStr property to Analog Input channel 0 for Analog Trigger Event 1 AnalogTriggerEvent1 ChanStr AIO Set up your program flow like this 1 Set the properties of the Analog Trigger Event control Next configure the acquisition or generation operations using the appropriate NI DAQ functions 2 Set the Enabled property of the Analog Trigger Event control to 1
205. ry and an analog input reading if one is available AI_Check is intended for use when A D conversions are initiated by external pulses applied at the appropriate pin see DAQ Config in the NI DAQ Function Reference Online Help file for information on enabling external conversions AI Clear Clears the analog input circuitry and empties the FIFO memory AI Change Parameter Selects a specific parameter setting for the analog input section or analog input channel Use this to set the coupling for AI channels AI_ Configure Informs NI DAQ of the input mode single ended or differential input range and input polarity selected for the device Use this function if you change the jumpers affecting the analog input configuration from their factory settings For the E Series devices which have no jumpers for analog input configuration this function programs the device for the settings you want For the E Series devices you can configure the input mode and polarity on a per channel basis Also use AI_ Configure to specify whether to drive AISENSE to onboard ground NI DAQ User Manual for PC Compatibles 3 16 ni com Chapter 3 Software Overview AI Mux Config Configures the number of multiplexer AMUX 64T devices connected to an MIO and AI device and informs NI DAQ if any AMUX 64T devices are attached to the system This function applies only to the MIO and AI devices AI Read Reads an analog input channel initiates an A D conversion o
206. s counter usage 3 50 FIFO lag effect 3 51 to 3 52 PCI 6115 and PCI 6120 devices groups of ports 3 56 to 3 57 pattern generation 3 74 to 3 75 PCLK1 signal table 3 105 PCLK2 signal table 3 105 PC LPM 16 counter timer signals 3 25 interval counter timer operation 3 92 LPM16_Calibrate function 3 4 period and continuous pulse width measurement applications 3 89 to 3 91 plug in device support AT PC and NEC buses table 1 4 PC Card CardBus and VXI buses table 1 5 PCI buses table 1 4 PXI buses table 1 5 programmable frequency output operation 3 81 pulse generation application tips 3 83 to 3 84 CTR_ Pulse function 3 77 flow chart 3 83 retriggerable one shot pulse 3 84 pulse per second synchronization 3 96 to 3 97 pulse width measurement event counting application 3 86 to 3 87 period and continuous pulse width measurement applications 3 89 to 3 91 R reference voltages for analog output devices bipolar output polarity table 3 49 to 3 50 unipolar output polarity table 3 49 ni com REQ signal 653X RTSI connections table 3 105 DIO 32F RTSI connections table 3 104 REQ signal 653X RTSI connections table 3 105 DIO 32F RTSI connections table 3 104 retriggerable one shot pulse 3 84 RTD_Buf_Convert function 5 2 to 5 4 RTD_Convert function definition 5 1 purpose and use 5 2 to 5 4 RTSI bus application tips 3 106 to 3 107 description 3 102 to 3 103 RTSI bus connectio
207. s and indicates the number of waveform cycles to generate For the 67 LX devices E Series devices and AT AO 6 10 this function also enables or disables FIFO mode waveform generation Converts a waveform generation update rate into the timebase and update interval values needed to produce the rate you want ni com Chapter 3 Software Overview WFM Scale Translates an array of floating point values that represent voltages into an array of binary values that produce those voltages The function uses the current analog output configuration settings to perform the conversions WFM_ Set _Clock Sets an update rate for a group of channels Waveform Generation Application Tips This section outlines a basic explanation of constructing an application with the Waveform Generation functions The flowcharts are a quick reference for constructing potential applications from the NI DAQ function calls Basic Waveform Generation Applications A basic waveform application outputs a series of voltages to an analog output channel Figure 3 15 illustrates the ordinary series of calls for a basic waveform application The first step of Figure 3 15 calls WFM_Scale The WFM_Scale function converts floating point voltages to integer values thus producing the voltages DAC values you want You have two options available for starting a waveform generation The first option is to call the high level function WFM_Op The WFM_Op function immediately b
208. s of data NI DAQ User Manual for PC Compatibles Chapter 3 Software Overview Digital Change Notification Functions The Digital Change Notification functions provide messaging for lines and ports on the 652X devices For other boards such as the DIO 24 the Config DAQ Event Message function handles event messaging DIG Change Message Config Configures 652X devices to detect rising or falling edges on input lines and to notify you by generating a message DIG Change Message_Control Controls the change notification operation of the digital input lines on 652X devices Digital Filtering Function The Digital Filtering function provides signal conditioning to filter the inputs of 652X devices DIG Filter Config Configures filtering for the input lines on 652X devices Digital Change Notification Applications with 652X Devices Digital change notification applications automatically detect changes on input lines and notify you or your software by message These applications may use digital filtering to eliminate signals that may trigger unwanted change notification Digital filtering can be used alone to condition and debounce input data Figure 3 18 illustrates the series of calls needed for change notification on the input data Figure 3 19 illustrates the series of calls needed for filtering the input data without change notification Only 652X devices can execute change notification and filtering applications using these functio
209. so NI DAQ events in Visual Basic for Windows application tips 3 5 to 3 6 Config_Alarm_Deadband 3 5 Config_ATrig_Event_Message 3 5 Config_DAQ _Event_Message 3 5 event procedures 3 6 external device support table parallel port 1394 and other devices 1 6 SCXI and USB devices 1 6 external multiplexer support AMUX 64T 3 25 external triggering of waveform generation 3 52 EXTUPD signal table 3 104 EXTUPDATE signal table 3 104 F FIFO lag effect 3 51 to 3 52 frequency measurement 3 87 to 3 88 frequency output counter timer functions 3 81 functions analog input functions one shot analog input functions 3 16 to 3 19 single channel analog input application tips 3 17 to 3 19 single channel analog input functions 3 16 to 3 19 NI DAQ User Manual for PC Compatibles Index analog output functions application tips 3 36 to 3 38 list of functions 3 35 to 3 36 counter timer functions application tips 3 82 to 3 91 counter timer operation 3 78 to 3 81 device support table 3 76 general purpose counter timer functions 3 93 interval counter timer functions 3 91 to 3 92 list of functions 3 77 to 3 78 programmable frequency output operation 3 81 data acquisition functions application tips 3 24 to 3 32 double buffered data acquisition application tips 3 31 to 3 32 high level data acquisition functions 3 20 to 3 21 low level data acquisition functions 3 21 to 3 23 low level double buffered data ac
210. sor that you can use for this purpose The TempScale integer indicates in which temperature unit you want your return values to be Constant definitions for each temperature scale are shown in the conversion header file 1 Celsius 2 Fahrenheit 3 Kelvin 4 Rankine The Thermocouple Convert routine has two remaining parameters TC Volts is the voltage that NI DAQ read from the thermocouple and TCTemp is the return temperature value The Thermocouple Buf Convert routine has three remaining parameters numPts is the number of voltage points to convert TCVoltBuf is the array that contains the voltages that NI DAQ read from the thermocouple and TCTempBuf is the return array that contains the temperatures Using This Function These routines convert TCVolts or each element of TC VoltBuf into a corresponding temperature after performing the necessary cold junction compensation Cold junction compensation is done by converting CJCTemp into an equivalent thermocouple voltage and adding it to TCVolts The actual temperature to voltage conversion is done by choosing the appropriate reference equation that characterizes the correct temperature subrange for the specific TCType The valid temperature range for a given TCType is divided into several subranges with each subrange characterized by a reference equation The computed voltage is then added to TC Volts to perform the cold junction correction The conversion of TC Volts into a correspo
211. streaming data to disk or acquiring a certain number of data points Examples of low level functions are writing directly to the DAQ device registers or calibrating the analog inputs NI DAQ does not sacrifice the performance of National Instruments DAQ devices because it lets multiple devices operate at their peak performance NI DAQ includes a Buffer and Data Manager that uses sophisticated techniques for handling and managing data acquisition buffers so that you can acquire and process data simultaneously NI DAQ can transfer data using DMA interrupts or software polling NI DAQ can use DMA to transfer data into memory above 16 MB even on ISA bus computers With the NI DAQ Resource Manager you can use several functions and several devices simultaneously The Resource Manager prevents multiboard contention over DMA channels interrupt levels and RTSI channels National Instruments Corporation 1 1 NI DAQ User Manual for PC Compatibles Chapter 1 Introduction to NI DAQ NI DAQ can send event driven messages to Windows or Windows NT applications each time a user specified event occurs Thus polling is eliminated and you can develop event driven DAQ applications Some examples of NI DAQ user events are e When a specified number of analog samples has been acquired e When the analog level and slope of a signal match specified levels e When the signal is inside or outside a voltage band e When a specified digital I O pattern is matched
212. ta remaining in the FIFO for the specified channel The same is true for the RESUME operation on a group 1 channel NI DAQ cannot place data for the specified channel into the FIFO until the FIFO is empty e WFM Check The values returned in pointsDone and itersDone indicate the number of points that NI DAQ has written to the FIFO for the specified channel A time lag occurs from the point when NI DAQ writes the data to the FIFO when NI DAQ outputs the data to the DAC e When you use double buffered waveform generation with group 1 make sure the total number of points for all of the group 1 channels specified in the count parameter in WFM_Load is at least twice the size of the FIFO Refer to your device user manual for information on the analog output FIFO size e For 61XX devices with onboard memory data is transferred to the memory in blocks of 32 bytes Therefore when you use double buffered waveform generation that does not end in a 32 byte sample boundary the last few points will not be output With PCI E Series 622XI devices and 671X devices in NI DAQ 5 1 and later you can reduce or even eliminate the FIFO lag effect by specifying the FIFO condition NI DAQ uses to determine when to put more data into the FIFO Refer to the AO Change Parameter function in NI DAQ Function Reference Online Help file for details Externally Triggering Your Waveform Generation Operation You can initiate a waveform generation operation from an ex
213. ter 2 to produce the sample timebase counter 2 is available to the other group only if the timebase is the same as the timebase required by the Waveform Generation functions to produce the total update interval In this case counter 2 produces the same timebase for both waveform generation groups FIFO Lag Effect on the MIO E Series AT AO 6 10 NI 4451 for PCI NI 4551 for PCI 622XI and 671X Devices Group 1 analog output channels use an onboard FIFO to output data values to the DACs NI DAQ continuously writes values to the FIFO as long as the FIFO is not full NI DAQ transfers data values from the FIFO to the DACs at regular intervals using an onboard or external clock You see a lag effect for group 1 channels because of the FIFO buffering That is a value written to the FIFO is not output to the DAC until all of the data values currently in the FIFO have been output to the DACs This time lag is dependent upon the update rate specified in WFM_ClockRate Refer to your device user manual for a more detailed discussion of the onboard FIFO National Instruments Corporation 3 51 NI DAQ User Manual for PC Compatibles Chapter 3 Software Overview Three functions are affected by the FIFO lag effect wFM_Chan_Control WFM_ Check and double buffered waveform generation WFM Chan _Control When you execute operation PAUSE for a group 1 channel the effective pause does not occur until the FIFO has finished writing all of the da
214. ternal trigger signal in much the same manner as for analog input See the Select _Signal function in the NI DAQ Function Reference Online Help file Digital 1 0 Function Group The Digital I O function group contains three sets of functions the Digital T O DIG functions the Group Digital I O DIG_Block DIG_Grp and DIG_SCAN functions and the double buffered Digital I O DIG_DB functions Refer to the NI DAQ Functions Listed by Hardware Product NI DAQ User Manual for PC Compatibles 3 52 ni com Chapter 3 Software Overview section in the NI DAQ Function Reference Online Help file to find out which digital functions your device supports The SCXI functions control the SCX digital and relay modules These devices contain a number of digital I O ports of up to eight digital lines in width The name port refers to a set of digital lines Digital lines are also referred to as bits in this text In many instances you control the set of digital lines as a group for both reading and writing purposes and for configuration purposes For example you can configure the port as an input port or as an output port which means that the set of digital lines making up the port consist of either all input lines or all output lines In NI DAQ you refer to ports by number Many digital I O devices label ports by letter For these devices use port number 0 for port A port number 1 for port B and so on For example the DIO 24 contains three por
215. ternal conversion pulses with AI_Clear AI_Setup and AI_Check to sample your signal on the analog input channels See Figure 3 2 for the function flow typical of single point data acquisition using external conversion pulses However this method works only if your computer is faster than the rate of conversion pulses Refer to the Data Acquisition Functions section later in this chapter to learn more about interrupt and DMA driven data acquisition by using high speed data acquisition When you are using SCXI analog input modules use the SCXI functions to set up the SCXI chassis and modules before using the AI functions described in Figures 3 1 and 3 2 Change analog input default configuration AI_Configure Add AMUX 64T configuration AI_Mux_Config Clean up onboard FIFO y memory for new conversion AI Clear Select an analog Y input channel AI_ Setup P Check for new data in V FIFO memory AI_Check Yes Another reading Figure 3 2 Single Point Analog Reading with External Conversion Timing National Instruments Corporation 3 19 NI DAQ User Manual for PC Compatibles Chapter 3 Software Overview Data Acquisition Functions High Level Data Acquisition Functions These high level data acquisition functions are synchronous calls that acquire data and return when data acquisition is complete Refer to the NI DAQ Function Reference Online Help file to determi
216. tion Figure 5 1 shows the seven bridge configurations supported and the corresponding formulas For all bridge configurations NI DAQ uses the following formula to obtain V V strainVolts Vinit Vex In the circuit diagrams shown in Figure 5 1 Voy is the voltage you measure and pass to the Strain Convert function as the strainVolts parameter In the quarter bridge and half bridge configurations R4 and R are dummy resistors that are not directly incorporated into the conversion formula The SCXI 1121 and SCXI 1122 modules provide R4 and R for a bridge completion network if needed Refer to your Getting Started with SCXI manual for more information on bridge completion networks and voltage excitation National Instruments Corporation 5 5 NI DAQ User Manual for PC Compatibles Chapter 5 Transducer Conversion Functions RL WW Rg e RL W res Rg dumm AL g y bridgeConfig 1 QTR_BRIDGE_I bridgeConfig 2 QTR_BRIDGE_Il 4Vr RL i 4Vr RL strain A 1 strain SFGov x GF 1 2V a RL Ni R1 ran SS Rg e ra RL iS 7 ae 7 J on Ww ii 7 9 a mA i R2 RL Raye bridgeConfig 3 HALF_BRIDGE_ bridgeConfig 4 HALF_BRIDGE_lII i Ar RL 2Vr RL t n eemnes strain GFO Nr VT strain GE 1 Rg bridgeConfig 6 FULL_BRIDGE ll i x 2Vr Nr strain strain
217. tion that the assigned DAQ device will perform The function downloads a module scan list to Slot 0 that determines the sequence of scanned modules and how many channels on each module are scanned This function can program each module with its given start channel as well as resolve any contention on the SCXIbus Changes the configuration of the SCXI chassis that you established in Measurement amp Automation Explorer Sets the software states of the chassis and modules specified to their default states Does not change the SCXI chassis or module hardware states Sets a specified excitation parameter to a supplied value on a given channel or all channels on the SCXI 1520 SCXI 1530 SCXI 1531 and SCXI 1540 modules ni com SCXI_Set_Gain SCXI_Set_Input_Mode SCXI_Set_State SCXI_Set_Threshold SCXI_Single Chan Setup SCXI_Track_Hold_Control SCXI_Track_Hold_Setup National Instruments Corporation 3 111 Chapter 3 Software Overview Sets the specified channel to the given gain or range setting on any SCXI module that works with programmable gain or range settings Configures the SCXI 1122 for differential mode or 4 wire mode Sets the state of a single channel or an entire port on any digital or relay module Used to set the high and low threshold values for the SCXI 1126 frequency to voltage module Sets up a multiplexed module for a single channel analog input operation to be performed by the given DA
218. tion to NI DAQ About the NI DAQ Software for PC Compatibles 20 0 0 eee eeceessceeceeeeeeeeseteeeesetsees 1 1 How to Set Up Your DAQ System eee eeseesecseeseeesecseeeseeseceesaeseeessessaeeeeeeeeaees 1 2 NIEDAQO OvervieW onae E ladees enews idan eae tees 1 3 NI DAQ Hardware Support 0 0 0 cee eececeseeeeeeseceeesseeseseaeceeceaeeeeeaesneeeaeenaes 1 4 NI DAQ Language Support 0 cee eee eeeeseeeseeeceeeeseesseeascnsessesnsesseenaeesees 1 7 Device Configurations i en nire a des ceeds cbectenss cosas seed Ue EEE E Sevens 1 7 Using Measurement amp Automation EXplorer esseeesserereereersrrserresrrerssesrses 1 7 Chapter 2 Fundamentals of Building Windows Applications The NEDA O OE S A e a a a EAS 2 1 Creating a Windows Application Using Microsoft Visual C 2 2 Developing an NI DAQ Application eceeseesceesseceseeeseeeeaeeeeeesneeeteeeeeeenaes 2 2 Example Programs ennenen a a eae lies 2 2 Special COnSiderations 3 sce cssessvesievessuvesstovvey a ewe ates cee pete aes 2 3 Butter Allocation esis kstieieteies ian E ae 2 3 Stins PASSING 2 aiea es eee des a RSE EEA E era 2 3 Parameter Passings csissucediersilva a a a eae 2 3 Creating a Windows Application Using Microsoft Visual Basic eee eeeeeeeees 2 4 Developing an NI DAQ Application ccceseesceeeneceseeeeeetsneceneeeseeeeeeeneeeeaes 2 4 Example Programs Arere a ourdre eia eai as e a Ai 2 5 Special Considerations iecrioua i e a ian aE RE S 2 5 Butler Al
219. tions 3 30 to 3 31 ni com building block 4 cleaning up 3 31 DAQCard 500 700 516 devices and LPM device counter timer signals 3 25 double buffered data acquisition 3 31 to 3 32 external multiplexer support AMUX 64T 3 25 Lab and 1200 device counter timer signals 3 24 data acquisition functions high level data acquisition functions 3 20 to 3 21 DAQ_Op 3 20 DAQ_to_Disk 3 20 Lab_ISCAN_Op 3 20 Lab_ISCAN_to_Disk 3 20 SCAN_Op 3 21 SCAN_to_Disk 3 21 low level data acquisition functions 3 21 to 3 23 DAQ_ Check 3 21 DAQ Clear 3 21 DAQ Config 3 21 DAQ Monitor 3 21 DAQ Rate 3 22 DAQ_Set_clock 3 22 DAQ Start 3 22 DAQ _StopTrigger_Config 3 22 DAQ_VScale 3 22 Lab_ISCAN_Check 3 22 Lab_ISCAN_Start 3 22 SCAN_Demux 3 22 SCAN_Sequence_Demux 3 22 to 3 23 3 33 SCAN_Sequence_Retrieve 3 23 3 33 SCAN_Sequence_Setup 3 23 3 33 SCAN_Setup 3 23 SCAN_Start 3 23 National Instruments Corporation l 5 Index low level double buffered data acquisition functions 3 23 to 3 24 DAQ_DB_Config 3 23 4 10 DAQ_DB_HalfReady 3 24 4 12 DAQ_DB_Transfer 3 24 4 11 multirate scanning 3 32 to 3 34 data acquisition rates SCXI modules 3 124 to 3 126 device configuration NI DAQ hardware support tables 1 4 to 1 6 using Measurement amp Automation Explorer 1 7 devices See also specific device e g AT AO 6 10 MIO and AI device terminology table xv xvii reference voltages for analog output devic
220. to or from the circular buffer call the DIG_DB_ Transfer function After you call the function NI DAQ waits until it can transfer the data before returning to the application To avoid the waiting period call DIG_DB HalfReady to determine if NI DAQ can make the transfer immediately If DIG_DB_HalfReady indicates that NI DAQ is not ready for a transfer your application can do other processing and check the status later After the final transfer you can call DIG_Block_ Check to get the current progress of the transfer For example if you are using double buffered output NI DAQ requires some time after the final transfer to actually output the data In addition if NI DAQ completes the block operation prior to aDIG_Block_Check call DIG_Block_Check automatically calls DIG _Block_Clear to perform cleanup work The final step of a double buffered block operation is to call DIG_Block_Clear which performs the necessary cleanup work after a digital block operation You must explicitly call this function if DIG _Block_Check did not already call it ky Note DIG Block Clear halts any ongoing block operation Therefore call DIG_Block_ Clear only if you are certain the block operation is complete or if you want to stop the current operation National Instruments Corporation 3 73 NI DAQ User Manual for PC Compatibles Chapter 3 Software Overview Pattern Generation 1 0 with the DIO 32F 653X PCI 6115 and PCI 6120 Devices Use pattern gener
221. transfer buffer This situation is illustrated by Figure 4 2 Incoming Device Data yy y Circular Buffer y Transfer Buffer Empty Buffer Untransferred Data Transferred Data Overwrite Before Figure 4 2 Double Buffered Input with an Overwrite Before Copy Notice that in Figure 4 2b NI DAQ has missed the opportunity to copy data from the first half of the circular buffer to the transfer buffer while the DAQ device is writing data to the second half As a result the DAQ device begins overwriting the data in the first half of the circular buffer before NI DAQ has copied it to the transfer buffer Figure 4 2c To guarantee uncorrupted data NI DAQ must wait until the device finishes overwriting data in the first half before copying the data into the transfer buffer After the device has begun to write to the second half NI DAQ copies the data from the first half of the circular buffer to the transfer buffer Figure 4 2d NI DAQ User Manual for PC Compatibles 4 4 ni com Chapter 4 NI DAQ Double Buffering For the previously described situation NI DAQ returns an overwrite before copy warning overWriteError This warning indicates that the data in the transfer buffer is valid but some earlier input data has been lost Subsequent transfers will not return the warning as long as they keep pace with the DAQ device as in Figure 4 1
222. ts of eight digital lines each Ports 0 1 and 2 are labeled PA PB and PC on the DIO 24 I O connector The eight digital lines making up port 0 lines 0 through 7 are labeled PAO through PA7 In some cases you can combine digital I O ports into a larger entity called a group On the DIO 32F and 653X devices for example you can assign any of the ports DIOA through DIOD to one of two groups On the PCI 6115 and PCI 6120 you can also create groups smaller than the port size For example both the PCI 6115 and the PCI 6120 have one digital port of eight lines but you can configure five lines as an input group and three lines as an output group A group of ports are handshaked or clocked as a unit The Digital I O functions can write to and read from both an entire port and single digital lines within the port To write to an entire port NI DAQ writes a byte of data to the port in a specified digital output pattern To read from a port NI DAQ returns a byte of data in a specified digital output pattern The byte mapping to the digital I O lines is as follows Table 3 6 Byte Mapping to Digital I O Lines Bit Number Digital I O Line Number 7 7 Most significant bit MSB 6 6 5 5 4 4 3 3 National Instruments Corporation 3 53 NI DAQ User Manual for PC Compatibles Chapter 3 Software Overview Table 3 6 Byte Mapping to Digital I O Lines Continued Bit Number Digital I O Line Number
223. uble Buffer Transfer Functions After a double buffered operation begins the Double Buffer Transfer functions transfer data to or from a circular buffer The direction of the transfer depends on the direction of the double buffered operations Along with copying data the Double Buffer Transfer functions also check for possible errors during the transfer For input operations DB_Transfer copies data from alternating halves of the circular input buffer to the transfer buffer For output operations DB_ Transfer copies data from the buffer passed to the function to alternating halves of the circular output buffer The function might return an overwrite before a copy warning or an overwrite error overWriteError if a problem occurs during the transfer B Note Waveform transfer functions do not detect overwrite before copy or overwrite errors NI DAQ User Manual for PC Compatibles 4 10 ni com Chapter 4 NI DAQ Double Buffering The DB_ Transfer functions for DAQ WFM DIG and GPCTR are synchronous for both input and output operations In other words when your application calls these functions NI DAQ does not return control to your application until the transfer is complete As a result your application might crash if NI DAQ cannot complete the transfer To avoid this situation call the Timeout_Config function for DAQ WFM DIG and GPCTR prior to starting a double buffered operation The timeout configuration function sets the maximum time a
224. ut Applications in Multiplexed Mode Multiplexed applications require the use of SCXI functions to select the multiplexed channels select the programmable module features route signals on the SCXIbus and program Slot 0 After you have set up the SCXI chassis and modules you can use the AI DAQ SCAN and Lab_ISCAN functions to acquire the data either with a plug in DAQ device or the SCXI 1200 The channel parameter that is passed to each of these functions is almost always 0 because the multiplexed output of a module is connected by default to analog input channel 0 of the DAQ device or SCXI 1200 If you are using a PXI DAQ device with an internal connection to the PXI 1010 or PXI 1011 SCXIbus then ND_PXxI_ SC is the channel parameter When you use multiple chassis the modules in each chassis are multiplexed to a separate analog input channel In that case the channel parameters of the AI DAQ SCAN and Lab_ISCAN functions should be the DAQ device channel that corresponds to the chassis you want for the operation You cannot use the SCXI 1200 with multiple chassis National Instruments Corporation 3 113 NI DAQ User Manual for PC Compatibles Chapter 3 Software Overview Figure 3 42 shows the function call sequence of a single channel or software scanning application using an SCXI 1100 SCXI 1101 SCXI 1102 B C VXI SC 1102 B C SCXI 1104 C SCXI 1112 SCXI 1120 D SCXI 1121 SCXI 1122 SCXI 1125 SCXI 1126 SCXI 1141 SCXI 1142 SCXI
225. ut of bounds 4 Voltage within bounds 5 Analog positive slope triggering 6 Analog negative slope triggering 7 Digital pattern not matched 8 Digital pattern matched 9 Counter pulse event DAQTrigValo Long DAQTrigVal1 Long TrigSkipCount Long National Instruments Corporation NI DAQ User Manual for PC Compatibles Chapter 3 Software Overview Table 3 1 General DAQ Event Control Properties Continued Property Allowed Property Values PreTrigScans Long PostTrigScans Long Index N A Tag N A Enabled 0 False default 1 True Some General DAQ Events can be implemented only by a select group of National Instruments DAQ devices Also some General DAQ Events require that you set the asynchronous data acquisition or generation operation to use interrupts For more information on the different types of General DAQ Events refer to the description for the Config DAQ Event Message function in the NI DAQ Function Reference Online Help file Set each of these properties as follows GeneralDAQEventn property name property value For example to set the ChanStr property to Analog Input channel 0 for GeneralDAQEvent 1 GeneralDAQEvent1 ChanStr AIO Set up your program flow like this 1 Set the properties of the General DAQ Event control Then configure the acquisition or generation operations using the appropriate NI DAQ functions 2 Set the Enabled property of the G
226. veform Generation Application National Instruments Corporation 3 43 NI DAQ User Manual for PC Compatibles Chapter 3 Software Overview Basic Waveform Generation with Pauses The application skeleton described in this section is nearly identical to the basic waveform generation application skeleton The difference is that the description in this section includes the pause and resume operations Figure 3 16 illustrates the ordinary series of calls for a basic waveform application with pauses The first step of Figure 3 16 calls WFM_Group_Setup The WFM Group_ Setup function assigns one or more analog output channels to a group The second step is to assign a buffer to the analog output channels using the calls WFM_ Scale and WFM_ Load The WFM_ Scale function converts floating point voltages to integer values that produce the voltages you want The WFM_Load function assigns a waveform buffer to one or more analog output channels The next step is to assign an update rate to the group of channels using the calls WFM_Rate and WFM_ClockRate The WFM_Rate function converts a data output rate to a timebase and an update interval that generates the rate you want The WFM_ClockRate function assigns a timebase update interval and delay interval to a group of analog output channels Notice that there are restrictions for using the WFM_ClockRate function to specify delay rate Refer to the WFM_ClockRate function description in the NI DAQ Functio
227. ver to an NI TIO device on each system and connects the scan clock to the gate input of the clock The first active edge on the scan clock on each system will record the global time that sample was taken The user can use the sample rate on each system to calculate the absolute time each sample was taken assuming sample rates remain constant throughout the experiment The software program flow is as follows 1 Initialize the clock for this application e Specify the synchronization signal source PFI line RTSI line e Specify the synchronization method If source is PPS read the current time from the GPS receiver via a serial port and set it as the initial DHMS value of the clock or choose any arbitrary value Initialization will take about 2 seconds If source is IRIG B simply wait for 2 seconds after programming the hardware The clock will automatically synchronize to the GPS signal e Specify gate signal source and polarity e Clock value automatically latches upon receiving the first pulse on its gate input 2 Poll the armed attribute of the clock until it is disarmed when the external event happens The clock is always armed in hardware but the software abstraction of the clock will be unarmed after it latches the first point 3 Read the clock value days hours minutes seconds to determine the time of the external event 4 At the end of the operation free up any hardware and software resources After po
228. verview Call CTR_Config to configure each counter used for simultaneous operations CTR_Config Select all counters for simultaneous operations CTR_Simul_Op Call CTR_EvCount for each counter selected through CTR_Simul_Op CTR_EvCount Simultaneously start all counters CTR_Simul_Op Simultaneously save all counter values CTR_Simul_Op CTR_EvRead Read all counters again Yes No Call CTR_Reset for each counter to terminate event counting CTR_Reset Cancel reservation of counters CTR_Simul_Op Call CTR_EvRead to retrieve each counter value Figure 3 30 Simultaneous Counter Operation National Instruments Corporation 3 85 NI DAQ User Manual for PC Compatibles Chapter 3 Software Overview Event Counting Applications CTR_EvCount and CTR_EvRead work with four types of event counting timing measurements event counting pulse width measurement time lapse measurement and frequency measurement CTR_EvCount also supports the concatenation of counters so that you can obtain 32 bit or 48 bit resolution for these measurements For event counting applications the events counted are the signal transitions or edges of an input SOURCE signal therefore you should set timebase to a value from 6 10 NI DAQ can count either low to high or high to low edges this feature is selected by edgeMode in the CTR_Config function In addition you can us
229. vices in the same computer direct current Direct Digital Synthesis A plug in DAQ board card or pad that can contain multiple channels and conversion devices Plug in boards PCMCIA cards and devices such as the DAQPad 1200 which connects to your computer parallel port are all examples of DAQ devices SCXI modules are distinct from devices with the exception of the SCXI 1200 which is a hybrid an analog input consisting of two terminals both of which are isolated from computer ground whose difference is measured See port Deutsche Industrie Norme German Industrial Standard digital I O the addition of Gaussian noise to the analog input signal NI DAQ User Manual for PC Compatibles G 4 ni com DLL DMA driver DSA DSP DSUB E EEPROM EGA EISA event driven message external trigger National Instruments Corporation G 5 Glossary Dynamic link library A software module in Microsoft Windows containing executable code and data that can be called or used by Windows applications or other DLLs Functions and data in a DLL are loaded and linked at run time when they are referenced by a Windows application or other DLLs Direct memory access a method by which data can be transferred to from computer memory from to a device or memory on the bus while the processor does something else DMA is the fastest method of transferring data to from computer memory software that controls a specific hardware devi
230. wering up the clock will run until the power to the TIO ASIC is turned off NI DAQ User Manual for PC Compatibles 3 100 ni com Chapter 3 Software Overview Use Case 3 The user generates a single trigger pulse event on two physically distributed data acquisition systems A user wants to generate a sine wave at location A and make buffered analog input measurements at location B at precisely the same time The sine wave generated at location A affects the measurements made at location B The software program flow is as follows 1 Initialize the clock for this application Specify the synchronization signal source PFI line RTSI line Specify the synchronization method If source is PPS read the current time from the GPS receiver via a serial port and set it as the initial DHMS value of the clock or choose any arbitrary value Initialization will take about 2 seconds For more information on initializing the clock with PPS refer to the SetUpClockUsingPPS section If source is IRIG B simply wait for 2 seconds after programming the hardware The clock will automatically synchronize to the GPS signal Route the PPS output of the receiver to one of the counter source lines for the TIO counter to receive 2 Set up the counter National Instruments Corporation Configure one of the counters for single pulse generation Application type single pulse generation Source source line carrying the PPS si

NI-DAQ User Manual for PC Compatibles, Version 6.9

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