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Traditional NI-DAQ User Manual

1. 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 0 001 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 Traditional NI DAQ User Manual Technical Support and Professional Services Visit the following sections of the National Instruments Web site at ni com for technical support and professional services e Support Online technical support resources include the following Self Help Resources For immediate answers and solutions visit our extensive library of technical support resources available in English Japanese and Spanish at ni com support These resources are available for most products at no cost to registered use
2. Number of Single Ended Device SE Channels Bit Type Functionality PXI 6040E 16 12 bit PXI MIO PXI 6052E 16 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 Traditional NI DAQ User Manual xii ni com Introduction to Traditional NI DAQ This chapter presents an overview of Traditional NI DAQ About the Traditional NI DAQ Software Thank you for buying a National Instruments DAQ device which includes Traditional NI DAQ software Traditional 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 RTST multiboard synchronization Traditional 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 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 Traditional NI DAQ does not sacrifice the performance of National Instruments DAQ devices because it lets multiple devices operate at their peak performance Traditional NI DAQ includes a Buffer and Data Manager that uses sophisticated techniques for handling and managing data acquisition buffers so you can acquire and proce
3. c ccccccesssecccceessscecceeesssscececeessscececessnaaeesees 5 2 Usine This Fineto a seer a a e e 5 3 Strain_Convert and Strain_Buf_Convett ccccccccsssssssssscccccscecsecesesesesesesees 5 4 Parameter DisCUSSION reena a aaa 5 4 Using This Function enano n E sea tania 5 5 Thermistor _Convert and Thermistor_Buf_Convert ccccccesesssssssesceeseeeeees 5 7 Parameter DISCUSSION cciisesseicedscsieescavdesevescescousdenctcssesveenescousescetssdeds 5 7 Using This FUNCHON 2 ce o2t a E OR a aa 5 7 Thermocouple_Convert and Thermocouple_Buf_Convert ceeeeeeeeeee 5 9 Parameter DisCuSSION cccccsssssccccessssccccecessscececesssaceeecesssaneeeees 5 9 Using This Function 2 3 20 fi ek Aa eile hth wa en ei 5 10 Appendix A Technical Support and Professional Services Glossary Index Traditional NI DAQ User Manual viii ni com About This Manual The Traditional NI DAQ User Manual is for users of the Traditional NI DAQ application programming interface API of the NI DAQ software version 7 0 NI DAQ is a powerful API between your data acquisition DAQ application and the National Instruments DAQ devices This manual includes source code for several example applications How to Use the Traditional NI DAQ Documentation Set Begin by reading the NI DAQ 7 0 readme file and the DAQ Quick Start Guide for NI DAQ 7 0 for information on how to set up your DAQ system using Traditional NI DAQ Rea
4. Prefix Meaning Value u micro 10 m milli 103 k kilo 103 M mega 10 Symbols Numbers B coefficient d coefficient degree minus Q ohm percent plus plus or minus E strain 0A temperature coefficient at T 0 C 1102 B C modules refers to the SCXI 1102 SCXI 1102B and SCXI 1102C modules 44XX device refers to the PCI 4451 PCI 4452 PCI 4454 PCI 4472 PXI 4472 and PCI 4474 45XX device refers to the PCI 4551 and PCI 4552 6025E device refers to the PCI 6025E and PXI 6025E National Instruments Corporation G 1 Traditional NI DAQ User Manual Glossary 6052E device 61XX device 652X device 653X device 660X device 6602 device 671X device 673X devices A A D AC ACK ActiveX ActiveX control ADC ADC resolution Al AMD Traditional NI DAQ User Manual refers to the PCI 6052E PXI 6052E and DAQPad 6052E for FireWire refers to the PCI 6110 PCI 6111 PCI 6115 PXI 6115 PCI 6120 and PXI 6120 refers to the PCI 6527 and PXI 6527 refers to the AT DIO 32HS PCI DIO 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 refers to the PCI 6731 PXI 6731 PCI 6733 and PXI 6733 analog to digital alternating current acknowledge a programming system and user interface
5. For more about GPCTR functions refer to the GPCTR_Set_Application function description in the Traditional NI DAQ C Reference Help National Instruments Corporation 3 77 Traditional NI DAQ User Manual Chapter 3 Software Overview Clocks or Time Counters Sample Use Cases Traditional NI DAQ User Manual 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 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 The following 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 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 undefin
6. retCnt is the value returned from the called function You can call a DAQ function that returns an unsigned 16 bit value and stores it in retCnt if retCnt lt 0 then myUnsignedCnt CInt retCnt 4294967296 else myUnsignedCnt retCnt end if To pass an unsigned 32 bit value to a function with an unsigned 32 bit type parameter you must first compute the value to pass to the function Dim myUnsignedCnt As Double Dim ToPassVal As Long You compute the value that you want to pass to the function and store it in myUnsignedCnt 2 7 Traditional NI DAQ User Manual Chapter 2 Fundamentals of Building Windows Applications if myUnsignedCnt gt 2147483647 then ToPassVal CLng myUnsignedCnt 4294967296 else ToPassVal CLng myUnsignedCnt end if Traditional NI DAQ Examples The Traditional NI DAQ installer installs a suite of concisely written examples in the following application development environments 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 These examples illustrate how to use Traditional 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 exa
7. National Instruments Corporation 2 9 Traditional NI DAQ User Manual Software Overview This chapter describes the function classes in Traditional NI DAQ and briefly describes each function Traditional NI DAQ functions are grouped according to the following classes e Initialization and general configuration e 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 National Instruments Corporation 3 1 Traditional NI DAQ User Manual Chapter 3 Software Overview e Counter Timer function group Counter timer Interval counter timer General purpose counter timer e RTSI bus trigger e SCXI e Transducer conversion Initialization and General Configuration Functions Use these general functions for initializing and configuring your hardware and software Refer to the Traditional NI DAQ C Reference Help to determine which functions your device supports Align_DMA_Buffer Aligns the data in a DMA buffer to avoi
8. Traditional NI DAQ User Manual 3 58 ni com Chapter 3 Software Overview DIG_Trigger_Config Enables or disables the trigger mode of buffered digital I O to indicate when to start and stop the data acquisition Double Buffered Digital 1 0 Functions The double buffered digital I O DIG_DB functions perform double buffered operations during Group Digital I O operations Refer to the Traditional NI DAQ C Reference Help to determine which functions your device supports DIG_DB_Config Enables or disables double buffered digital transfer operations and sets the double buffered options DIG_DB_HalfReady 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 DIG_DB_Transfer For an input operation DIG_DB_Transfer waits until Traditional 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 Traditional 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 buffers of data National Instruments Corporation 3 59 T
9. 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 y SCXI_Set_Gain E e Acquire data from the y desired channel on the y f module using the AT Sere Single Analog Input functions or the DAQ Single Channel Data Acquisition functions If desired change the selected channel on the module SCXI_Change_Chan Have you acquired all the data you need from this module Figure 3 31 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 National Instruments Corporation 3 91 Traditional NI DAQ User Manual Chapter 3 Software Overview Traditional NI DAQ User Manual The SCXI_Set_Gain function changes the gain or range of the SCXI 1100 SCXI 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 maintains this gain or range setting until yo
10. 3 55 6353X DEVIC Groups rennene gara err AER EE AE TEN RER 3 55 PCI 6115 PCI 6120 and 673X Device Groups sssssessesersersererserersersreersee 3 56 Digital VO Functions Ti iier as ena E a o E E E E ERETT 3 57 Group Digital I O Functions sseessesesesssseesesesesrsresrestsresteestestesrnresreresresrereses 3 58 Double Buffered Digital I O Functions essesesseeesseseseerssrerssreresresrsresrsresrssese 3 59 Digital Change Notification Functions ccccceccececeeseesecseseessessenseneeneenes 3 60 Digital Filters Functions eain Wes Gate eed Soe 3 60 Digital Change Notification Applications with 652X Devices 3 60 Digital Change Detection Applications with 653X Devices 3 61 Digital I O Application Tips eee eee ee cseceeeseceseeeeeseeseeeseceeesesseseaeesees 3 62 Handshaking Versus No Handshaking Digital I O 0 3 63 Digital Port I O Applications eee eeeceseeeeeeseceeceeeeseeeaeesees 3 63 Digital Line I O Applications 20 0 ieee cceeseceseeseeeseenecnseeseeesececnsesseeeaeesees 3 65 Digital Group I O Applications cece eee eeeeeeseeeeseeseeeseeeeesesseeeeeeaeenees 3 67 Traditional NI DAQ User Manual vi ni com Contents Digital Group Block I O Applications cei ee ee ceeeseeeeeeeeeeeeeeeeeeeeseeenees 3 68 Pattern Generation I O with 653X PCI 6115 PCI 6120 and 673X Devi E Sman a E REER A E AR a 3 72 Double Buffered P O nunun srs oa eaea ia 3 73 Counter Timer Function G
11. Traditional NI DAQ User Manual Chapter 3 3 Software Overview 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 653X PCI 6115 PCI 6120 or 673X 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 653X device you can alter the handshaking mode of the group by calling DIG_Grp_Mode For the 653X PCI 6115 PCI 6120 and 673X 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 in the Pattern Generation I O with 653X PCI 6115 PCI 6120 and 673X Devices section for more information The next step for your application as illustrated in Figure 3 25 is to call DIG_Block_In or DIG_Block_Out to start the data 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 D
12. 7 Digital pattern not matched 8 Digital pattern matched 9 Counter pulse event DAQTrigVal0 Long National Instruments Corporation 3 7 Traditional NI DAQ User Manual Chapter 3 Software Overview Traditional NI DAQ User Manual Table 3 1 General DAQ Event Control Properties Continued Property Allowed Property Values DAQTrigVall Long TrigSkipCount Long 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 Traditional NI DAQ C Reference Help Set each of t hese 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 Traditional NI DAQ functions 2 Set the 1 Enabled property of the General DAQ Event control to 1
13. IRIG B stream 3 79 PPS stream 3 79 Config_Alarm_Deadband function 3 5 Config_ATrig_Event_Message function 3 5 Config _DAQ_ Event_Message function 3 5 Traditional NI DAQ User Manual l 2 configuration NI DAQ 1 2 using Measurement amp Automation Explorer 1 2 configuration functions See also initialization and general configuration functions AI_Change_Parameter 3 16 AI_Configure 3 16 AI_Mux_Config 3 16 AI_Setup 3 17 AO_Configure 3 35 Config_Alarm_Deadband 3 5 Config_ATrig_Event_Message 3 5 Config _DAQ_ Event_Message 3 5 Configure_HW_Analog_Trigger 3 4 DAQ Config 3 22 DAQ_DB_ Config 3 24 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 57 DIG_SCAN_Setup 3 58 DIG_Trigger_Config 3 59 GPCTR_Change_Parameter 3 76 4 10 GPCTR_Config_Buffer 3 76 MIO_Config 3 4 SCXI_Configure_Connection 3 86 SCXI_Configure_Filter 3 86 SCXI_Load_Config 3 86 SCXI_MuxCtr_Setup 3 87 SCXI_SCAN_ Setup 3 87 SCXI_Set_Config 3 87 SCXL_ Set_Excitation 3 88 SCXIL_Set_Gain 3 88 SCXI_Set_Input_Mode 3 88 SCXI_Set_State 3 88 ni com SCXI_Set_Threshold 3 88 SCXI_Single_Chan_Setup 3 88 SCXI_Track_Hold_Setup 3 89 Timeout_Config 3 3 WEM_DB_Config 3 40 4 10 WFM_Group_Setup 3 40 Configure_HW_Analog_ Trigger function 3 4 contacting National Instruments A 1 conven
14. True 3 Invoke the General DAQEVventn Refresh method to set the DAQ Event in the Traditional 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 4 Start an asynchronous data acquisition or generation operation 3 8 ni com Chapter 3 Software Overview 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 refer to the General DAQ Event example at the end of the Traditional NI DAQ Events in Visual Basic section Analog Trigger Event Use the Analog Trigger Event control to configure and enable an analog trigger Refer to 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 Properties Property Allo
15. 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 thermistor and TempBuf is the return array of temperature values assigned in units determined by TempScale Using This Function The following equation expresses the relationship between Volts and R the thermistor resistance Refer to Figure 5 2 R Volts Yal a National Instruments Corporation 5 7 Traditional NI DAQ User Manual Chapter 5 Traditional NI DAQ User Manual Transducer Conversion Functions Solving the previous equation for Ry we have Volts n Rg t 1 V a 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 _ 1 a b 1nR e 1nR 3 The values used fora b and c are given below
16. Chapter 3 Software Overview Traditional NI DAQ User Manual 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 Traditional 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 In many of the data acquisition function descriptions in the Traditional NI DAQ C Reference Help 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 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 each module You also can use the SCXI_Configure_Filter function for the SCXI 1122 SCXI 1125 SCXI 1126 SCXI 1141 SCXI 1142 SCXI 1143 SCXI 1530 and SCXI 1531 and the SCXI_Set_Input_Mode function for the SCXI 1122 The SCXI_MuxCtr_Setup call s
17. E a i a eee iaaii 2 3 Butter Allocation 3 23 ks ettatthas ieee ad 2 3 Stana Passini aereo ia en seven suey ceeds suteers sysop E EE E ayes beet 2 3 Parameter Passing o tesla degen aA EEE EA nE 2 3 Creating a Windows Application Using Microsoft Visual Basic 0 0 0 eee eens 2 3 Developing a Traditional NI DAQ Application ceeceescesecneeeneeeeeeeee 2 4 ExamplesProsranmss aace eA A cea tees E E 2 4 Special Considerations 000 0 eee e A A 2 5 Buller Allocation 2 00 ds te e aT a A REES 2 5 String Passing nenn e a a RO ee Ree hie 2 6 Parameter Passing ennir a E ded bovtes 2 6 Passing Unsigned 16 Bit and 32 Bit Integer Parameters 2 6 Traditional NFDAQ Example Sesine inreds a n e 2 8 National Instruments Corporation V Traditional NI DAQ User Manual Contents Chapter 3 Software Overview Initialization and General Configuration Functions ee eeeeseessceseeeeeeseteeeeseeeees 3 2 Software Calibration and Device Specific Functions 0 0 0 eile ee eeeeseeseeeeeteeeeeeeseeeaees 3 3 Event Message FUNCIONS aioin cios e feted ae LR ae eee ate 3 5 Event Messaging Application Tips eee eeeseeseeeseeneenseeeeeseceeeseeseseaeesees 3 5 Traditional NI DAQ Events in Visual Basic cccccccesssesesseeeeseeeesseeesseeees 3 6 ActiveX Controls for Visual Basic oo eee ese eeeeseeeeeeseeseeeseeeees 3 6 General DAQ Event sinner in isi anoir eaor 3 7 Analog Frie ger Evette ee E ARS 3 9 Analog Alarm Event s 5
18. General Purpose Counter Timer Functions Use the General Purpose Counter Timer GPCTR functions with the E Series 660X 671X 673X and DSA devices Refer to the GPCTR functions in the Traditional NI DAQ C Reference Help for a detailed description of how to use the GPCTR functions for a variety of applications GPCTR_Change_Parameter GPCTR_Config_Buffer GPCTR_Control GPCTR_Read_Buffer GPCTR_Set_Application GPCTR_Watch Customizes the counter operation to fit the requirements of your application by selecting a specific parameter setting Assigns the buffer that Traditional NI DAQ uses for a buffered counter operation Controls the operation of the General Purpose Counter Timer Transfers data from the previously assigned buffer during an asynchronous counter operation Selects the application for which you use the General Purpose Counter Timer The function description in the Traditional NI DAQ C Reference Help contains many application tips Monitors the state of the General Purpose Counter Timer and its operation 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 28 Traditional NI DAQ User Manual 3 76 ni com Chapter 3 Software Overvie
19. NI DAQ User Manual 3 60 ni com Chapter 3 Software Overview Digital Change Detection Applications with 653X Devices For change detection on the 653X refer to the DIG_Block_PG_Config function in the function reference For message generation on the 653X and many other devices refer to the Config_DAQ_Event_Message function in the function reference Enable filtering DIG_Filter_Config Configure Change Notification y DIG_Change_Message_Config Start Change Notification y DIG_Change_Message_Control 1 y 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 Traditional NI DAQ User Manual Chapter 3 Software Overview Enable filtering DIG_Filter_Config Optional on 652X Devices y
20. 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 SCXI 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 34 shows the function call sequence of a single channel or software scanning operation using these modules in parallel mode National Instruments Corporation 3 97 Traditional NI DAQ User Manual Chapter 3 Software Overview Configure the desired module for a single channel operation y SCXI_Track_Hold_Setup Latch the analog inputs by y putting the module into Hold mode SCXI_Track_Hold_Control Ea Acquire data from the desired channel on the module using the AT functions y Single Analog Input Do you wish to take more data while the module is in Hold mode Yes Maintain Hold mode 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 Disable the Track Hold setup of the module to free the counter resource on the data acquisition device SCXI_Track_Hold_Setup Figure 3 34 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
21. SOURCE increments or decrements the counter e GATE is used to indicate when to start or stop counting intervals or when to save the counter contents in the save register e AUX UP_DOWN controls the direction of the counting When configured for hardware control of counting direction the counter counts up when AUX UP_DOWN is high and it counts down when AUX UP_DOWN is low When using a counter for pulse generation the input signals perform the following functions e The counter uses SOURCE as a timebase to generate the pulse e The user specifies the pulse parameters in terms of periods of the SOURCE input e GATE can serve as a trigger signal to generate a pulse after the first active gate edge or after each active gate edge The GATE input can operate in either buffered or non buffered mode Buffered measurements are similar to their single measurement counterparts However multiple successive measurements are made The result of each measurement is saved in the Hardware Save Register on each active edge of GATE A buffered measurement generates a data stream This data stream is transferred to your computer via DMA or interrupts The maximum transfer rates for these buffered measurements are system dependent Non buffered measurements do not use a buffer Unbuffered data appears on the OUT output on each active edge of GATE National Instruments Corporation 3 75 Traditional NI DAQ User Manual Chapter 3 Software Overview
22. 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 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 Traditional NI DAQ has updated the circular buffer with new data from the transfer buffer This situation is illustrated by Figure 4 5 Notice that in Figure 4 5b Traditional 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 Traditional NI DAQ has updated it with data from the transfer buffer Figure 4 5c To guarantee uncorrupted output data Traditional 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 Traditional 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 Traditional NI DAQ User Manual Chapte
23. a flowchart outlining the basic line I O application TIO DSA 62XX 652X PCI PXI 6703 6704 DIO 6533 DIO 32HS or E Series device Yes y Configure lines for input y Configure ports for input DIG_Line_Config DIG_Prt_Config gt y y DIG_In_Line DIG_In_Prt No Yes Traditional NI DAQ User Manual Figure 3 22 Basic Line Input or Output Application First configure the digital lines for input or output You can program 653X devices PCI 6703 PCI 6704 PXI 6703 PXI 6704 671X 673X 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 call DIG_In_Line or DIG_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 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 information except for the PCI 6115 PCI 6120 and 673X devices which can create groups smaller than the port size for
24. 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 powering up the clock will run until the power to the TIO ASIC is turned off RTSI Bus Trigger Functions The Real Time System Integration RTSD Bus Trigger functions connect and disconnect signals over the RTSI bus trigger lines Refer to the Traditional NI DAQ C Reference Help to determine which functions your device supports National Instruments Corporation 3 79 Traditional NI DAQ User Manual Chapter 3 Software Overview RTSI Bus Traditional NI DAQ User Manual RTSI_Clear Disconnects all RTSI bus trigger lines from signals on the specified device RTSI_Clock Connects or disconnects the system clock from th
25. both waveform generation and analog input data acquisition Refer to the WFM_Set_Clock function in the Traditional NI DAQ C Reference Help for an explanation of the restrictions this causes This counter is separate from the general purpose counters The MIO 671X 673X and E Series devices use dedicated counters from the DAQ STC chip for waveform generation control and timing 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 counter 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 NI 4451 for PCI NI 4551 for PCI 671X and 673X Devices Group 1 analog output channels use an onboard FIFO to output data values to the DACs Traditional NI DAQ continuously writes values to the FIFO as long as the FIFO is not full Traditional NI DAQ transfers data values from the FIFO to the DACs at regular intervals using an onboard or externa
26. buffered data acquisition functions 3 24 digital I O function group 653X device groups 3 55 application tips 3 62 byte mapping to digital I O lines table 3 54 digital I O functions 3 57 digital line I O applications 3 65 DIO 24 6025E AT MIO 16DE 10 and DIO 96 device groups 3 55 double buffered digital I O functions 3 59 group digital I O functions 3 58 overview 3 53 PCI 6115 PCI 6120 and 673X device groups 3 56 event message functions application tips 3 5 list of functions 3 5 NI DAQ events in Visual Basic for Windows 3 6 initialization and general configuration functions 3 2 list of function groups 3 1 RTSI bus trigger functions 653X RTSI connections 3 81 application tips 3 83 E series DSA 660X and 671X RTSI connections 3 81 ni com list of functions 3 79 SCXI functions application tips 3 89 list of functions 3 84 software calibration and device specific functions 3 3 transducer conversion functions function descriptions 5 2 list of functions 5 1 overview 5 1 waveform generation functions application tips 3 41 high level waveform generation functions 3 39 low level waveform generation functions 3 39 G General DAQ Event controls examples 3 8 properties table 3 7 setting properties 3 8 general purpose counter timer functions application tips 3 76 GPCTR_Change_Parameter 3 76 4 10 GPCTR_Config_Buffer 3 76 GPCTR_Control 3 76 GPCTR_Read_Buffer 3 76 GPCTR_Set_Applicat
27. controls 3 13 NI DAQ installation See installation NI DAQ libraries for Windows 2 1 NI DAQ software features 1 1 overview 1 2 nidaq32 dll note 2 1 NI TIO based devices See clocks or time counters for NI TIO devices no handshaking mode 3 55 0 one shot analog input functions AI_Change_Parameter 3 16 AIL Check 3 16 AI Clear 3 16 AI_Configure 3 16 AI_Mux_Config 3 16 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 one shot analog output functions AO_Change_Parameter 3 35 AO_Configure 3 35 AO_Update 3 35 AO_VScale 3 35 AO_VWrite 3 36 Traditional NI DAQ User Manual Index AO_ Write 3 36 application tips 3 36 online technical support A 1 P Parallel mode applications SCXI modules 3 96 parameter passing in Windows applications Microsoft Visual Basic 2 6 Microsoft Visual C 2 3 pattern generation I O with 653X PCI 6115 PCI 6120 and 673X devices 3 72 PC DIO 24 groups of ports 3 53 PCI 4451 devices counter usage 3 51 FIFO lag effect 3 51 PCI 6115 and PCI 6120 devices groups of ports 3 56 pattern generation 3 72 PCLK1 signal table 3 82 PCLK2 signal table 3 82 PC LPM 16 counter timer signals 3 25 LPM16_Calibrate function 3 4 phone technical support A 1 professional services A 1 programming examples A 1 R reference voltages for analog output devices bipolar output polarity table 3 50 unip
28. 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 Traditional NI DAQ User Manual Chapter 3 Software Overview Account for changes in the jumper settings Enable software voltage update y AO_Configure y Output voltage to board AO_VWrite p Wait until you are ready to output voltage Update Yes Output voltage from board AO_Update No Done outputting data Yes 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 3 Note Implement buffered analog output using the Waveform Generation wFM functions Traditional NI DAQ User Manual 3 38 ni com Chapter 3 Software Overview Waveform Generation Functions Use the Waveform Generation wFM functions to perform buffered analog output operations with the MIO devices 671X devices 673X devices and AT AO 6 10 devices Refer to the Traditional NI DAQ C Reference Help to determine which functions your device supports High Level Waveform Generation
29. digital operations Figure 3 23 is a flowchart for group digital applications that handshake one point at a time Only the 653X devices can execute group input or output one point at a time y Configure groups for input or output DIG_Grp_Config y After handshaking mode DIG_Grp_Mode gt a Check if group is ready for transfer Not Ready DIG_Grp_Status y Input data from group y Output data to group DIG_In_Grp DIG_Out_Grp y Figure 3 23 Simple Digital Group Input or Output Application 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 second step of Figure 3 23 to alter the handshaking National Instruments Corporation 3 67 Traditional NI DAQ User Manual Chapter 3 Software Overview mode of the 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 third step 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 flowchart is to loop back until all of the data has been input or output Digital Group Block 1 0 Applications Traditional NI DAQ al
30. 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 clear 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 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 National Instruments Corporation 3 73 Traditional NI DAQ User Manual Chapter 3 Software Overview 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 Traditional NI DAQ reprograms the DMA For a group configured for pattern generation this split can cause glitches in the digital input or outp
31. 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 Traditional 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 Traditional 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 Traditional 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 Corporation 3 5 Traditional NI DAQ User Manual Chapter 3 Software Overview After your application receives an event message it can carry out the appropriate
32. 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 Traditional NI DAQ User Manual 3 98 ni com Chapter 3 Software Overview 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 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 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 AT function calls refer to the DAQ device channels and gains Use the data acquisition channels that correspond to the module channels you want as described earlier in this section Figure 3 35 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 y Acquire data from the desired channels using interval scanning with the SCAN and Lab_ISCAN functions y Scanned Data Acquisition Have you acquired all the data you need No Yes Disable the Track Hold setup of the module to free the counter resource on the data acquisition boa
33. is analogous to waveform generation but instead of writing voltages to the analog output channels Traditional NI DAQ writes digital patterns to the digital ports The 653X PCI 6115 PCI 6120 and 673X use DMA to service pattern generation However certain buffers require Traditional 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 Traditional NI DAQ Double Buffering for more information Double Buffered 1 0 With the double buffered DIG_pDB 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 Traditional 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
34. it to the transfer buffer This situation is illustrated by Figure 4 2 Incoming Device Data y Circular Buffer y Transfer Buffer Empty Buffer Untransferred Data Transferred Data Overwrite Before Traditional NI DAQ User Manual Figure 4 2 Double Buffered Input with an Overwrite Before Copy Notice that in Figure 4 2b Traditional 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 Traditional NI DAQ has copied it to the transfer buffer Figure 4 2c To guarantee uncorrupted data Traditional 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 Traditional NI DAQ copies the data from the first half of the circular buffer to the transfer buffer Figure 4 2d 4 4 ni com Chapter 4 Traditional NI DAQ Double Buffering For the previously described situation Traditional 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 warn
35. refer to DAQ_Config in the Traditional NI DAQ C Reference Help 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 Traditional 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 AI_Mux_Config Configures the number of multiplexer AMUX 64T devices connected to an MIO and AI device and informs Traditional NI DAQ User Manual 3 16 ni com AI_Read AI_Read_Scan AI_Read_VScan AI_Setup AI_VRead AI_VScale Chapter 3 Software Overview Traditional NI DAQ if any AMUX 64T devices are attached to the system This function applies only to the MIO and AI devices Reads an analog input channel initiates an A D conversion on an analog input channel and returns the unscaled result Returns reading
36. sequential half buffers of the data Traditional NI DAQ User Manual 3 24 ni com Chapter 3 Software Overview Data Acquisition Application Tips 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 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 Traditional NI DAQ functions comprising each building block vary Typical applications can include the Traditional NI DAQ functions in each of their four building blocks Configuration Start Checking Cleaning up Figure 3 3 Buffered Data Acquisition Basic Building Blocks 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 flowc
37. the pretrigger mode of data acquisition and indicates the number of data points to acquire after you apply the 3 22 ni com DAQ_VScale Lab_ISCAN_Check Lab_ISCAN_Start SCAN_Demux SCAN_Sequence_Demux SCAN_Sequence_Retrieve SCAN_Sequence_Setup National Instruments Corporation 3 23 Chapter 3 Software Overview 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 from each channel is stored in adjacent elements of your buffer Returns the scan sequence created by Traditional NI DAQ as a result of a previous call to SCAN_Sequence_Se
38. 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 Traditional 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 By default all analog output channels for 671X 673X and MIO devices are in group 1 Assigns a waveform buffer to one or more analog output channels and indicates the number of waveform cycles to generate For the 671X devices 673X devices and E Series devices 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 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 ni com Chapter 3 Software Overview analog output configuration settings to perform the conversions WFM_Set_Clock Sets a
39. 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 y and the number of channels to scan on each module 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 1148 or 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_MuxCtr_Setup Acquire the data using the SCAN or Lab_ISCAN functions Remember if there are any SSH modules to be scanned you must use interval scanning Scanned Data Acquisition Have you acquired all the data you need gt p Disable the Track Hold setup of the SSH modules to free the counter resource on the DAQ device SCXI_Track_Hold_Setup y Figure 3 33 Channel Scanning Operation Using Modules in Multiplexed Mode 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 National Instruments Corporation 3 95 Traditional NI DAQ User Manual
40. 4E 16 12 bit PCMCIA MIO DAQCard 6062E 16 12 bit PCMCIA MIO DAQPad 6020E 16 12 bit USB MIO Traditional NI DAQ User Manual X ni com About This Manual Table 1 MIO and Al Device Technical Details Continued Number of Single Ended Device SE Channels Bit Type Functionality DAQPad 6052E for 16 16 bit FireWire MIO FireWire DAQPad 6070E for 16 12 bit Fire Wire MIO FireWire PCI 6013 16 16 bit PCI MIO PCI 6014 16 16 bit PCI MIO PCI 6023E 16 12 bit PCI Al 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 Al PCI 6033E AI 64XE 10 64 16 bit PCI Al PCI 6034E 16 16 bit PCI Al PCI 6035E 16 16 bit AI 12 bit AO PCI MIO PCI 6040E 16 12 bit PCI MIO PCI MIO 16E 4 PCI 6052E 16 16 bit PCI MIO PCI 6070E 16 12 bit PCI MIO PCI MIO 16E 1 PCI 6071E MIO 64E 1 64 12 bit PCI MIO PCI 6110 4 DIFF only 12 bit AI 16 bit AO PCI MIO PCI 6111 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 16XE 10 16 16 bit PCI MIO PCI MIO 16XE 50 16 16 bit PCI MIO PXI 6025E 16 12 bit PXI MIO PXI 6030E 16 16 bit PXI MIO PXI 6031E 64 16 bit PXI MIO National Instruments Corporation xi Traditional NI DAQ User Manual About This Manual Table 1 MIO and Al Device Technical Details Continued
41. AQ User Manual Chapter 3 Software Overview Traditional NI DAQ User Manual 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 Traditional NI DAQ C Reference Help to determine which functions your device supports DAQ_Check Checks if the current data acquisition operation is complete and returns the status and the number of samples acquired to that point DAQ_ Clear Cancels the current data acquisition operation both single channel and multiple channel scanned and reinitializes the data acquisition circuitry DAQ_Config Stores configuration information for subsequent data acquisition operations DAQ_ Monitor 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 DAQ_ Rate Converts a data acquisition rate into the timebase and sample interval values needed to produce the rate you want DAQ_Set_Clock Sets the scan rate for a group of channels DAQ_ Start Initiates an asynchronous single channel data acquisition operation and stores its input in an array DAQ StopTrigger_Config Enables
42. AQ does not return control to your application until the transfer is complete As a result your application might crash if Traditional NI DAQ cannot complete the 4 10 ni com Chapter 4 Traditional NI DAQ Double Buffering 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 allocated 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 DAQ_DB_ Transfer WFM_DB_ Transfer DIG_DB_Transfer 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_Buf fer 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 d
43. Configure lines for input v Configure ports for input DIG_Line_Config DIG_Prt_Config AA y 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 Traditional NI DAQ User Manual 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 Traditional NI DAQ function calls 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 digital port The second met
44. DAQ Traditional NI DAQ User Manual Version 7 0 Data Acquisition Software for the PC Wy NATIONAL April 2003 Edition p INSTRUMENTS Part Number 370696A 01 Worldwide Technical Support and Product Information ni com National Instruments Corporate Headquarters 11500 North Mopac Expressway Austin Texas 78759 3504 USA Tel 512 683 0100 Worldwide Offices Australia 61 2 9672 8846 Austria 43 0 662 45 79 90 0 Belgium 32 0 2 757 00 20 Brazil 55 11 3262 3599 Canada Calgary 403 274 9391 Canada Montreal 514 288 5722 Canada Ottawa 613 233 5949 Canada Qu bec 514 694 8521 Canada Toronto 905 785 0085 Canada Vancouver 514 685 7530 China 86 21 6555 7838 Czech Republic 42 02 2423 5774 Denmark 45 45 76 26 00 Finland 385 0 9 725 725 11 France 33 0 1 48 14 24 24 Germany 49 0 89 741 31 30 Greece 30 2 10 42 96 427 Hong Kong 2645 3186 India 91 80 4190000 Israel 972 0 3 6393737 Italy 39 02 413091 Japan 81 3 5472 2970 Korea 82 02 3451 3400 Malaysia 603 9059 6711 Mexico 001 800 010 0793 Netherlands 31 0 348 433 466 New Zealand 64 09 914 0488 Norway 47 0 32 27 73 00 Poland 48 0 22 3390 150 Portugal 351 210 311 210 Russia 7 095 238 7139 Singapore 65 6 226 5886 Slovenia 386 3 425 4200 South Africa 27 0 11 805 8197 Spain 34 91 640 0085 Sweden 46 0 8 587 895 00 Switzerland 41 56 200 51 51 Taiwan 886 2 2528 7227 United Kingdom 44 0 1635 523545 For further support information refer to the Technical Support and Profe
45. E DESIGN PROCESS AND SAFETY LEVEL OF SUCH SYSTEM OR APPLICATION Contents About This Manual How to Use the Traditional NI DAQ Documentation Set cccesceeeseeeeeseeeeseeeees ix Conventions Used in This Manual ccccccscccssssccssseccesseeeesseeesseeesseeeesseeeessaeeessaeees ix MIO and AI Device Terminology 0 eee eececeeeseeceeseceseeseeeseeseeseeeasenseeaeenes X Chapter 1 Introduction to Traditional NI DAQ About the Traditional NI DAQ Software 0 cccccccsscceesseeeesneeeesneeeeeneeeeesseeesseeeeneneeeees 1 1 How to Set Up Your DAQ System eseesesesesereeserssrersersreersrsessereresesesesesseneesensereseersre 1 2 Traditional NI DAQ OVverview c ccccsssceessseeesseecesseeeeseseeessneeesseeeseeeeessneeeseaeeeseneeeees 1 2 Device Configuration si sivsscecsnes ccesteeticteceeetadacehey evens scuvleusde abu jetcheneeelendica Meus vsseveacstvetes 1 2 Using Measurement amp Automation Explorer eeeeseeseeeeseeeeeeseeees 1 2 Chapter 2 Fundamentals of Building Windows Applications The Traditional NI DAQ Libraries ccccccccccccsssssccccesesssccecceessssceeecesssseeeceeeessseeeeeens 2 1 Creating a Windows Application Using Microsoft Visual C eee eeeeeeeereeeees 2 2 Developing a Traditional NI DAQ Application cee cesceeeseeseeeeneeeneeenees 2 2 Example Programs sccsc isevihescdinn ceed dosh detentions ed Galas eae area 2 2 Special Consideratons y e s2 8 Aiea seve Ate ptte
46. Empty Buffer a 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 Traditional NI DAQ can copy the data from the first half into the transfer buffer Figure 4 1b You then can 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 Traditional 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 Traditional NI DAQ User Manual Chapter 4 Traditional 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 Traditional NI DAQ has copied
47. Eventn Refresh method to actually set the Analog Trigger Event in the Traditional 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 Traditional NI DAQ User Manual 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 Refer to 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 1 n default ChanStr Refer to Config_DAQ_Event_Message in the Traditional NI DAQ C Refer
48. 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 Temporarily 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 Traditional NI DAQ User Manual Chapter 3 Software Overview WFM_DB_Config WFM_DB_HalfReady WFM_DB_ Transfer WFM_Group_Control WFM_Group_Setup WFM_Load WFM_Rate WFM_Scale Traditional NI DAQ User Manual
49. IG_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 Traditional NI DAQ User Manual DIG_Block_Clear only if you are certain the block operation has completed or you want to stop the current operation 3 70 ni com Chapter 3 Software Overview y Configure groups for input or output DIG_Grp_Config y Enable double buffering DIG_DB Config Start block input y p DIG_Block_In y Start block output DIG_Block_Out No r DIG_DB_HalfReady Is Traditional NI DAQ ready to transfer Transfer next half of the data to or Yes from the digital data buffer Yes DAQ_DB_ DIG_Block_Check Transfer Do you wish to transfer more data to or from the digital buffer Any more data to output No Output operations only Clear block operation if No DIG_Block_Check did not DIG_Bl ock_Clear National Instruments Corporation Figure 3 25 Double Buffered Block Operation 3 71 Traditional NI DAQ User Manual Chapter 3 Software Overview The first step for an application is to call DIG_Grp_Co
50. IO devices system integration services A 1 T technical support A 1 telephone technical support A 1 Thermistor_Buf_Convert function 5 7 Thermistor_Convert function definition 5 1 purpose and use 5 7 Thermocouple_Buf_Convert function 5 9 Traditional NI DAQ User Manual Index Thermocouple_Convert function definition 5 1 purpose and use 5 9 time counters See clocks or time counters for NI TIO devices Timeout_Config function 3 3 training customer A 1 transducer conversion functions overview 5 1 RTD_Buf_Convert 5 2 RTD_Convert 5 1 5 2 Strain_Buf_Convert 5 4 Strain_Convert 5 1 5 4 Thermistor_Buf_Convert 5 7 Thermistor_Convert 5 1 5 7 Thermocouple_Buf_Convert 5 9 Thermocouple_Convert 5 1 5 9 troubleshooting resources A 1 V Visual Basic See Microsoft Visual Basic for Windows W waveform generation application tips basic applications 3 41 basic waveform generation with pauses 3 44 counter usage 3 51 double buffered applications 3 47 external triggering 3 52 FIFO lag effect 3 51 minimum update intervals 3 51 reference voltages for analog output devices bipolar output polarity table 3 50 unipolar output polarity table 3 50 Traditional NI DAQ User Manual I 12 waveform generation functions high level waveform generation functions WFM_from_Disk 3 39 WEFM_Op 3 39 low level waveform generation functions WEM_Chan_Control 3 39 WEM_Check 3 39 WEFM_ClockRate 3 39 WEF
51. If you are using a thermistor with different values for a b and c refer to 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 Refer to Figure 5 2 R NENG C t Solving the previous equation for R you have Volts ne R t XV mer 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 1 a b 1nR e 1nR 3 5 8 ni com Chapter 5 Transducer Conversion Functions 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 refer to you thermistor data sheet you can edit the thermistor conversion routine to use your own a b and c values a 1 295361E 3 b 2 343159E4 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 Traditional NI DAQ read from a thermocouple into temperature Parameter Discussion The TCType integer indicates what type of thermocouple Traditional NI DAQ used to read the tem
52. M_DB_ Config 3 40 4 10 WFM_DB_HalfReady 3 40 4 11 WFM_DB _ Transfer 3 40 4 11 WFM_Group_Control 3 40 WFM_Group_Setup 3 40 WEM_Load 3 40 WFM_Rate 3 40 WFM_ Scale 3 40 WFM_Set_Clock 3 41 Web professional services A 1 technical support A 1 WFM_Chan_Control function 3 39 3 52 WFM_ Check function 3 39 3 52 WFM_ClockRate function 3 39 WFM_DB_Config function 3 40 4 10 WFM_DB_HalfReady function 3 40 4 11 WFM_DB _ Transfer function 3 40 4 11 WFM_from_Disk function 3 39 WFM_Group_Control function 3 40 WEFM_Group_Setup function 3 40 WFM_Load function 3 40 WEM_Op function 3 39 WFM_ Rate function 3 40 WFM_ Scale function 3 40 ni com
53. 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 ARE 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 APPROPRIAT
54. SCAN_Sequence_Demux function Figure 3 11 Multirate Scanning Traditional NI DAQ User Manual 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 wF functions which perform buffered D A conversions Ss 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 Traditional NI DAQ C Reference Help 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 the 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
55. Unused Source internal clock or Source 7 receiver external clock 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 STOPTRIG1 and STOPTRIG2 signals in the DIG_Trigger_Config function in the Traditional NI DAQ C Reference Help Traditional NI DAQ User Manual 3 82 ni com Chapter 3 Software Overview RTSI Bus Application Tips This section gives a basic explanation of how to construct an application that uses RTSI bus Traditional NI DAQ functions Use the flowcharts as a quick reference for constructing potential applications from the Traditional 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 29 illustrates the normal order of RTSI function calls National Instruments Corporation 3 83 Traditional NI DAQ User Manual Chapter 3 Software Overview Connect clock signals on RTSI bus RTSI_Clo
56. _BRIDGE_1I Ri e bridgeConfig 2 QTR_BRIDGE_II bridgeConfig 5 FULL_BRIDGE_ Vr GF strain e strain e bridgeConfig 6 FULL_BRIDGE_II 2Vr GF v 1 strain bridgeConfig 7 FULL_BRIDGE_III 2Vr GF v 1 Vr v 1 R1 R2 dummy R AV RL in fo 4Vr RL strain e 44 Ee strain GF 1 2V Ry GF 1 2Vr R1 RL RL VW J VVV zis S1 R1 8 re ar RL gt I is tie oy Vex Con WW Vex or VW pe eee Roo iS bridgeConfig 3 HALF_BRIDGE_1 bridgeConfig 4 HALF_BRIDGE_II 4Vr RL 2Vr RL t strain GF 2 Vi x strain e GE 1 Ri Traditional NI DAQ User Manual Figure 5 1 Strain Gage Bridge Configuration 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 in volts Refer to Figure 5 2 The thermistor on the SCXI terminal blocks has a Ver of 2 5 V R is the value of the resistor in series with your thermistor in ohms Refer to Figure 5 2 The thermistor on the SCXI terminal blocks has an R value of
57. _Out_Prt Traditional NI DAQ User Manual Figure 3 20 Basic Port Input or Output Application with Handshaking 3 64 ni com Chapter 3 Software Overview DIG_Prt_Config Input data from port Output data to port DIG In Prt DIG OUE PrE No Yes Figure 3 21 Basic Port Input or Output Application without Handshaking 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 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 to read 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 Traditional NI DAQ User Manual Chapter 3 Software Overview Figure 3 22 is
58. acters 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 Italic text in this font denotes text that is a placeholder for a word or value that you must supply MIO and Al Device Terminology This manual uses generic terms to describe groups of devices whenever possible The generic terms for the multifunction I O MIO and analog input AJ devices are based on the number of bits the platform and the functionality The following table lists each MIO and AI device and the technical details for each Table 1 MIO and Al Device Technical Details Number of Single Ended Device SE 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 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 AI DAQCard 602
59. ads 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 Traditional NI DAQ User Manual Chapter 3 Software Overview SCXI_Set_Excitation SCXI_Set_Gain SCXTI_Set_Input_Mode SCXI_Set_State SCXI_Set_Threshold SCXI_Single_Chan_Setup SCXI_Strain_Null Traditional NI DAQ User Manual 3 88 MAX 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 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 DAQ device Sets the module channel enables the module output and routes the module o
60. aintain 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 32 Single Channel or Software Scanning Operation Using a Simultaneous Sample and Hold Module in Multiplexed Mode National Instruments Corporation 3 93 Traditional NI DAQ User Manual Chapter 3 Software Overview Notice the similarities between Figure 3 32 and Figure 3 33 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 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 33 shows the function call sequence of a channel scanning application in multiplexed mode Remember that only the MIO and AI devices 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 device the module directly connected to the DAQ device must be one of the SSH modules Traditional NI DAQ User Manual 3 94 ni com Chapter
61. aintains the current waveform voltage at the channel output 3 44 ni com Chapter 3 Software Overview Resume the waveform generation by calling WrM_Group_Control operation R ESUM E R ESUME 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 Traditional NI DAQ User Manual Chapter 3 Software Overview y Assign channels to waveform generation group WFM_Group_Setup y Convert floating point voltages to binary values WFM_Scale y Load waveform buffer and specify iterations WFM_Load y Convert output rate to timebase and interval WFM_Rate y Set the update and delay rates WFM_ClockRate y Start background waveform generation WFM_Group_Control operation RESUMI Should you pause waveform generation Yes Pause wave WFM_Group_Control Pause the No Start waveform generation where it was paused No Yy Resume waveform generation Resume wave WFM_Group_Control operation RESUME Yes Clear waveform WFM_Group_Control operatio
62. al a property of a DAQ device that has an extremely stable onboard reference and calibrates its own A D and D A circuits without manual adjustments by the user refers to the PCI 6110 PCI 6111 PCI 6115 PXI 6115 PCI 6120 PXI 6120 PCI 4451 PCI 4452 PCI 4454 PCI 4551 PCI 4552 PCI 4472 PXI 4472 and PCI 4474 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 terminal count the data measured in bytes s for a given continuous operation calculated to include software overhead refers to the SCXI 1140 SCXI 1520 SCXI 1530 and SCXI 1531 refers to the Traditional NI DAQ software unless otherwise noted 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 G 12 ni com U unipolar USB V V VDC VPICD Glossary 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 Nati
63. al NI DAQ C Reference Help to determine which functions your device supports AO_Calibrate 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 1 the first time a function pertaining to the AT AO 6 10 is called Calibrate_1200 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 National Instruments Corporation 3 3 Traditional NI DAQ User Manual Chapter 3 Software Overview Traditional NI DAQ User Manual Calibrate_TIO Calibrate_DSA Calibrate_E Series can store up to six sets of calibration constants Traditional NI DAQ automatically loads the calibration constants stored in EEPROM user area 5 the first time you call a function pertaining to the device Use the function to calibrate the crystal oscillator on your timing I O 660X device Use this function to calibrate your DSA device Use this function to calibrate yo
64. ard or pad that can contain multiple channels and conversion devices Plug in boards and PCMCIA cards are all examples of DAQ devices SCXI modules are distinct from devices 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 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 the addition of Gaussian noise to the analog input signal 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 device such as a DAQ board or a GPIB interface board dynamic signal acquisition Traditional NI DAQ User Manual Glossary DSA device DSP DSUB E EEPROM EGA EISA E Series device event driven mes
65. ata 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 Sy 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 data 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 b
66. be broken into two smaller groups These groups are referred to as group and 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 can be configured as an output group containing lines 1 3 5 and 7 and group 2 as an input group containing lines 0 2 4 and 6 A portion of the eight available lines can also be configured for group operations with the remaining unused lines configured for 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 and 4 and the group is to be written with all ones the hex value of 0x17 is passed to the function instead of OxF 3 56 ni com Chapter 3 Software Overview 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 operat
67. bed earlier in this chapter to acquire the input data Building Analog Input 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 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 If you are using a PXI DAQ device with an internal connection to the PXI 1010 or PXI 1011 SCXIbus then ND_PXI_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 3 90 ni com Chapter 3 Software Overview Figure 3 31 shows the function call sequence of a single channel or software scanning application using an SCXI 1100 SCXI 1101 SCXI 1102 B C SCXI 1104 C SCXI 1112 SCXI 1120 D SCXI 1121 SCXI 1122 SCXI 1125 SCXI 1126 SCXI 1141 SCXI 1142 SCXI 1143 SCXI 1520 SCXI 1530 SCXI 1531 or SCXI 1540 module operating in multiplexed mode
68. cannot use the SCXI 1162 HV or the SCXI 1163 R in parallel mode National Instruments Corporation 3 103 Traditional NI DAQ User Manual Traditional NI DAQ Double Buffering This chapter describes using double buffered data acquisitions with Traditional NI DAQ This chapter applies to counter operations however you can read samples of any size Overview 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 Traditional NI DAQ double buffered functions work Sy 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 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
69. 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 refer to the SCXI_Cal_Constants function description 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 SCKI_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 SCXI_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 Traditional NI DAQ maintains However if you are using the SCXI 1163 R in parallel mode SCXI_Get_State reads the hardware States Traditional NI DAQ User Manual 3 102 ni com Chapter 3 Software Overview 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 module channels The MIO and AI devices
70. 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 WeM_ClockRate function description in the Traditional NI DAQ C Reference Help 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 m
71. ck Connect each device signal to a specified RTSI bus trigger line A completed signal path y requires two RTSI_Conn calls RTSI_Conn Disconnect device signal from RTSI bus y A Disconnect all device ATOT DLECONH and clock signals from RTSI bus Disconnect clock signal y from RTSI bus v RTSI_Clear RTSI_Clock v Figure 3 29 Basic RTSI Application Calls 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 Traditional NI DAQ C Reference Help to determine which functions your device supports SCXI_AO_Write Sets the DAC channel on the SCXI 1124 module to the specified voltage or current output value You also can use this Traditional NI DAQ User Manual 3 84 ni com SCXI_Cal_Constants SCXI_Calibrate SCXI_Calibrate_Setup National Instruments Corporation Chapter 3 Software Overview function to write a bina
72. 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 3 80 ni com Chapter 3 Software Overview 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 671X and 673X RTSI Connections For information regarding signals on the E Series DSA 660X 671X and 673X devices that you can connect to the RTSI bus refer to the Select_Signal function description in the Traditional NI DAQ C Reference Help 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 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 refer to your device user
73. ction 3 60 DIG_Change_Message_Control function 3 60 Traditional NI DAQ User Manual l 4 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 DIG_Line_Config function 3 57 DIG_Out_Grp function 3 58 DIG_Out_Line function 3 57 DIG_Out_Prt function 3 57 DIG_Prt_Config function 3 57 DIG_Prt_Status function 3 57 DIG_SCAN_Setup function 3 58 DIG_Trigger_Config function 3 59 digital I O application tips digital change detection with 652X devices 3 60 with 653X devices 3 61 digital change notification with 652X devices 3 60 digital group block I O 3 68 digital group I O 3 67 digital line I O 3 65 digital port I O applications 3 63 double buffered I O 3 73 handshaking versus no handshaking digital I O 3 63 SCXI applications 3 89 digital I O functions byte mapping to digital I O lines table 3 54 DIG_In_Line 3 57 DIG_In_Prt 3 57 DIG_Line_Config 3 57 DIG_Out_Line 3 57 DIG_Out_Prt 3 57 DIG_Prt_Config 3 57 ni com Index DIG_Prt_Status 3 57 single buffered versus double buffered digital change notification functions 3 60 data 4 1 digital filtering function 3 60 double buffered functions double buffered digital I O functions configuration fun
74. ctions DIG_DB_Config 4 10 DAQ_DB_ Config 3 24 4 10 DIG_DB_HalfReady 3 59 4 12 DIG_DB_Config 3 59 4 10 DIG_DB_ Transfer 3 59 4 11 GPCTR_Change_Parameter group digital I O functions 3 76 4 10 DIG_Block_Check 3 58 WFM_DB_Config 4 10 DIG_Block_Clear 3 58 digital I O functions DIG_Block_In 3 58 applications DIG_Block_Out 3 58 double buffered I O 3 73 DIG_Block_PG_Config 3 58 group block I O DIG_Grp_Config 3 58 applications 3 68 DIG_Grp_Mode 3 58 DIG_DB_Config 4 10 DIG_Grp_Status 3 58 DIG_DB_HalfReady 3 24 DIG_In_Grp 3 58 3 59 4 12 DIG_Out_Grp 3 58 DIG_DB _ Transfer 3 59 4 11 DIG_SCAN_ Setup 3 58 HalfReady functions DIG_Trigger_Config 3 59 DAQ_DB_HalfReady 3 24 4 11 groups of ports DIG_DB_HalfReady 3 59 4 12 653X 3 55 GPCTR_Read_Buffer 4 12 DIO 24 6025E AT MIO 16DE 10 WFM_DB_HalfReady 4 11 and DIO 96 3 55 low level double buffered data PCI 6115 PCI 6120 and 673X 3 56 acquisition functions overview 3 53 application tips 3 31 DIO 96 groups of ports 3 55 DAQ_DB_Config 3 24 4 10 DAQ_DB_HalfReady 3 24 4 11 DAQ_ DB Transfer 3 24 4 11 transfer functions 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 drivers instrument A 1 software A 1 documentation conventions used in manual ix how to use NI DAQ manual set ix online library A 1 double buffered data acquisition appl
75. d crossing a physical page boundary This function is for use with DMA waveform generation and digital I O pattern generation Get_DAQ_Device_Info Retrieves parameters pertaining to the device operation Get_NI_DAQ Version Returns the version number of the Traditional NI DAQ library Init_DA_Brds 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 Traditional 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 Traditional NI DAQ software and for determining which Traditional NI DAQ User Manual 3 2 ni com Chapter 3 Software Overview device has been assigned to a particular slot number Set_DAQ_Device_Info Selects parameters pertaining to the device operation Timeout_Config 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 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 Tradition
76. d this manual to learn about programming with Traditional NI DAQ When you are familiar with the material in this manual you can begin to use the Traditional NI DAQ reference help files for more information on functions and VIs Other documentation includes Measurement amp Automation Explorer Help for Traditional NI DAQ a help file installed with Measurement amp Automation Explorer MAX For detailed hardware information refer to the user manual included with each device Conventions Used in This Manual 3 bold italic 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 from the last dialog box This icon denotes a note which alerts you to important information Bold text denotes items that you must select or click in the software such as menu items and dialog box options Bold text also denotes parameter names and function prototypes Italic text denotes variables emphasis a cross reference or an introduction to a key concept This font also denotes text that is a placeholder for a word or value that you must supply National Instruments Corporation ix Traditional NI DAQ User Manual About This Manual monospace monospace bold monospace italic Text in this font denotes text or char
77. e RTSI bus RTSI_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 Traditional NI DAQ C Reference Help to determine if your device supports RTSI The RTSI bus is implemented via a 34 pin ribbon cable connector on the AT PCI E Series PCI DSA 67LX and 673X devices On PXI DAQ and DSA devices the RTSI bus is implemented using PXI trigger bus lines On E Series DAQ devices for FireWire the RTSI bus is implemented with a 15 pin mini DSUB connector The RTSI bus has a 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 trigger one device from another device share clocks and signals between devices and synchronize devices to the same signals The RTSI bus also can
78. e to sample timebase and sample interval DAQ_Rate Sample multiple channels Select channels and their gain for multiple channel scanning SCAN_Setup Initiate single channel data acquisition Initiate multiple channel data acquisition DAQ_Start SCAN_Start t 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 Traditional NI DAQ User Manual 3 28 ni com Chapter 3 Software Overview sample timebase and Convert sampling rate to sample interval DAQ_Rate Yes No Sample multiple channels Initiate multiple channel data acquisition Initiate single channel data acquisition Lab_ISCAN_Start DAQ_ Start t Figure 3 7 Buffered Data Acquisition Application Building Block 2 Start for the LPM Devices When you have the asynchronous start calls in your building block 2 the next building block Checking is very useful for determining the status of the ongoing data acquisition process National Instruments Corporation 3 29 Traditional NI DAQ User Manual Chapter 3 Software Overview Building Block 3 Checki
79. eck functions 3 30 building block 4 cleaning up 3 31 double buffered data acquisition 3 31 external multiplexer support AMUX 64T 3 25 LPM device counter timer signals 3 25 data acquisition functions high level data acquisition functions DAQ_Op 3 20 DAQ to_Disk 3 21 Lab_ISCAN_Op 3 21 Lab_ISCAN_to_Disk 3 21 SCAN_Op 3 21 SCAN_to_Disk 3 21 low level data acquisition functions DAQ Check 3 22 DAQ Clear 3 22 DAQ Config 3 22 DAQ_ Monitor 3 22 Traditional NI DAQ User Manual Index DAQ Rate 3 22 DAQ_Set_Clock 3 22 DAQ Start 3 22 DAQ StopTrigger_Config 3 22 DAQ_ VScale 3 23 Lab_ISCAN_Check 3 23 Lab_ISCAN_ Start 3 23 SCAN_Demux 3 23 SCAN_Sequence_Demux 3 23 3 33 SCAN_Sequence_Retrieve 3 23 3 33 SCAN_Sequence_Setup 3 23 3 33 SCAN_Setup 3 24 SCAN_ Start 3 24 low level double buffered data acquisition functions DAQ_DB_Config 3 24 4 10 DAQ_DB_HalfReady 3 24 4 11 DAQ_DB _ Transfer 3 24 4 11 multirate scanning 3 32 data acquisition rates SCXI modules 3 100 device configuration NI DAQ 1 2 using Measurement amp Automation Explorer 1 2 devices See also specific device e g AT AO 6 10 MIO and AI device terminology x reference voltages for analog output devices tables 3 50 diagnostic resources A 1 DIG_Block_Check functions 3 58 DIG_Block_Clear functions 3 58 DIG_Block_In functions 3 58 DIG_Block_Out functions 3 58 DIG_Block_PG_Config functions 3 58 DIG_Change_Message_Config fun
80. ed 2 Read the clock value days hours minutes seconds when the external event happens to determine the time of the event 3 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 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 3 78 ni com Chapter 3 Software Overview Another user wants to correlate buffered analog input measurements across distributed data acquisition systems He connects a GPS receiver 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
81. ed high speed data logging The number of tasks you need for your applications depends on the types of DAQ devices you have and the complexity of your applications Device Configuration Before you begin your Traditional NI DAQ application development you must configure your National Instruments DAQ devices Traditional NI DAQ needs the device configuration information to program your hardware correctly Using Measurement amp Automation Explorer Measurement amp Automation Explorer MAX is a Windows based application that you use to configure and view National Instruments DAQ device settings under Windows 2000 NT XP Me 98 Sy Note To use MAX quit any applications that are performing DAQ operations Traditional NI DAQ User Manual 1 2 ni com Chapter 1 Introduction to Traditional NI DAQ Double click the Measurement amp Automation icon on your desktop to run MAX Refer to the Measurement amp Automation Explorer Help for Traditional NI DAQ for more information and detailed instructions on configuring your devices and accessories National Instruments Corporation 1 3 Traditional NI DAQ User Manual Fundamentals of Building Windows Applications This chapter describes the fundamentals of creating Traditional NI DAQ applications in Windows 2000 NT XP Me 98 The following section contains general information about building Traditional NI DAQ applications describes the nature of the Traditional NI DAQ files used
82. elay possible when calling the double buffer transfer function When you call either of the transfer functions Traditional 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 made your application can do other work and try again later The HalfReady functions are as follows DAQ_DB_HalfReady e WFM_DB_HalfReady National Instruments Corporation 4 11 Traditional NI DAQ User Manual Chapter 4 Traditional NI DAQ Double Buffering Conclusion DI G_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_DI B_ 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_Hal fReady 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 wit
83. enabled by a previous call to AO_Configure AO_VScale Scales a voltage to a binary value that when written to one of the analog output channels produces the specified voltage National Instruments Corporation 3 35 Traditional NI DAQ User Manual Chapter 3 Software Overview AO_VWrite 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 AO_Write 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 Traditional 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_vVWrite is the equivalent of a call to AO_VScale followed by a call to AO_Write Figure 3 12 illustrates the equivalency i Scale floating point voltage to binary value y Scale floating point voltage AO_VScale to binary value and output binary voltage to board Output binary voltage to board AO_VWrite AO_Write Figure 3 12 Equivalent Analog Output Calls The following applications are shown usi
84. ence Help HighAlarmLevel Single voltage LowAlarmLevel Single voltage HighDeadbandwWidth 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 Traditional NI DAQ C Reference Help National Instruments Corporation 3 11 Traditional NI DAQ User Manual Chapter 3 Software Overview Traditional NI DAQ User Manual 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 Traditional 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 Traditional 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 asynchro
85. eneric 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 Traditional NI DAQ User Manual 2 2 ni com Chapter 2 Fundamentals of Building Windows Applications Special Considerations When developing an application using Visual C consider the following special considerations Buffer Allocation To allocate memory you can use the Windows API function GlobalAlloc After allocation 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 Traditional 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_Buf fer 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 ay Note If you allocate memory from GlobalAlloc you must call GlobalLock on the memory object before passing it to Traditional 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 pass
86. es in the following sections show the detailed call sequences for different types of SCXI operations In effect each of the remaining National Instruments Corporation 3 89 Traditional NI DAQ User Manual Chapter 3 Software Overview Traditional NI DAQ User Manual flowcharts in this section is an enlargement of the Analog Input Operations the Analog Output Operations or the Digital Operations node in Figure 3 30 Refer to the function descriptions in the Traditional NI DAQ C Reference Help 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 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 AT 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 descri
87. es parameters by value Remember to pass pointers to variables when you need to pass by address 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 National Instruments Corporation 2 3 Traditional NI DAQ User Manual Chapter 2 Fundamentals of Building Windows Applications Developing a Traditional NI DAQ Application To develop a Traditional NI DAQ application follow these general steps 1 Open an existing or new Visual Basic project to manage your application code 2 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 3 Include the Traditional NI DAQ include file for Visual Basic nidaq32 bas into your project You also might want to include nidaqcens inc and nidagerr inc The Traditional 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 the Existing tab and 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 Traditional NI DAQ DLL In Visual Basic 5 0 6 0 select the Project gt References menu option and chec
88. et_Config 3 87 SCXL_Set_Excitation 3 88 SCXI_Set_Gain 3 88 SCXI_Set_Input_Mode 3 88 SCXIL_Set_State 3 88 SCXI_Set_Threshold 3 88 SCXI_Single_Chan_Setup 3 88 SCXI_Strain_Null 3 88 SCXI_Track_Hold_Control 3 89 SCXI_Track_Hold_Setup 3 89 SCXI_Calibrate function 3 4 Select_Signal function 3 4 3 80 Set_DAQ_ Device_Info function 3 3 setting up DAQ systems See device configuration installation single buffered versus double buffered data 4 1 single channel analog input functions AI_Change_Parameter 3 16 AI_Check 3 16 AL Clear 3 16 AI_Configure 3 16 AI_Mux_Config 3 16 AI_ Read 3 17 AI_Read_Scan 3 17 AI_Read_VScan 3 17 AI_ Setup 3 17 AI_VRead 3 17 National Instruments Corporation l 11 Index AI_VScale 3 17 application tips 3 17 software drivers A 1 software calibration and device specific functions AO_Calibrate 3 3 Calibrate_1200 3 3 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 85 SCXI_Calibrate 3 4 3 85 SCXI_Calibrate_Setup 3 85 Select_Signal 3 4 STOPTRIGI signal table 3 82 STOPTRIG2 signal table 3 82 Strain_Buf_Convert function 5 4 Strain_Convert function definition 5 1 purpose and use 5 4 string passing in Windows applications Microsoft Visual Basic 2 6 Microsoft Visual C 2 3 support technical A 1 synchronization of clocks See clocks or time counters for NI T
89. fficient 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 Traditional NI DAQ User Manual These functions convert a voltage or voltage buffer that Traditional NI DAQ read from a strain gage to units of strain Parameter Discussion The bridgeConfig integer indicates in what type of bridge configuration the strain gage is mounted Figure 5 1 shows all the different bridge configurations and the corresponding values that you should pass in bridgeConfig Vex is the excitation 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 gage factor of the strain gage v is Poisson s Ratio needed only in certain bridge configurations Rg is the strain gage 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 1S the unstrained voltage of the strain gage 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 gage conversion routines The Strain_Convert routine has two remaining pa
90. 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 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 National Instruments Corporation 3 19 Traditional NI DAQ User Manual Chapter 3 Software Overview Change analog input y 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 input channel Da y AI_Setup Check for new data in y FIFO memory AI_Check Yes Another reading Figure 3 2 Single Point Analog Reading with External Conversion Timing 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 Traditional NI DAQ C Reference Help to determine which functions your device supports Performs a synchronous single channel DAQ_Op data acquisition operation DAQ_Op does Traditional NI DAQ User Manual 3 20 ni co
91. 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 National Instruments Corporation 4 1 Traditional NI DAQ User Manual Chapter 4 Traditional NI DAQ Double Buffering 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 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 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 a
92. g 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 National Instruments refers to the NI DAQ software unless otherwise noted refers to the NI 4551 NI 4552 DAQCard 6601 PCI 6601 PCI 6602 PXI 6602 PCI 6608 PXI 6608 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 value within specified limits a technique used for extending the address range of a device to point into a larger address space 1 personal computer 2 Refers to the IBM PC XT IBM PC AT and compatible computers Peripheral Component Interconnect Traditional NI DAQ User Manual Glossary PCI Series port posttriggering PPS pretriggering programmed I O pts PXI R RAM REQ resolution ROM RTC RTD Traditional NI DAQ User Manual refers to the National Instruments products that use the high performance expansion bus architecture originally developed by Intel 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
93. group 2 Group 1 uses handshake lines REQ1 and ACK1 Group 2 uses handshake lines REQ2 and ACK2 The group National Instruments Corporation 3 55 Traditional NI DAQ User Manual Chapter 3 Software Overview 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 assigned ports to a group the group acts as a single entity controlling 8 16 or 32 digital lines simultaneously 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 Traditional NI DAQ C Reference Help PCI 6115 PCl 6120 and 673X Device Groups Traditional NI DAQ User Manual On the PCI 6115 PCI 6120 and 673X devices port 0 can
94. h 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 Traditional NI DAQ User Manual 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 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 4 12 ni com Transducer Conversion Functions This chapter describes the Traditional NI DAQ Transducer Conversion functions Traditional NI DAQ includes source code for these functions The Transducer Conversion functions convert analog input voltages read from thermocouples RTDs thermistors and strain gages 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 rou
95. harts National Instruments Corporation 3 25 Traditional NI DAQ User Manual Chapter 3 Software Overview Traditional NI DAQ User Manual 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 Configuration AI_Mux_Config Alter start trigger external conversion and external scan clock modes DAQ_ Config Alter pretrigger mode y DAQ_StopTrigger_Config vy Alter double buffered mode DAQ_DB_ Config y Figure 3 4 Buffered Data Acquisition Application Building Block 1 Configuration Traditional NI DAQ records the device configurations and the default configurations Refer to the Init_DA_Brds description in the Traditional NI DAQ C Reference Help 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 Building Block 2 Start Traditional NI DAQ has high level and low level start functions The high level start functions are as follows DAQ_Op e SCAN_Op MIO AI and DSA devices only 3 26 ni com Chapter 3 Software Over
96. he Microsoft Visual C IDE to manage your code development and that you are familiar with the IDE Developing a Traditional NI DAQ Application To develop a Traditional 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 Traditional NI DAQ header file nidag h as such in your source code files include nidaq h You also might want to include nidagcens h and nidagerr h You also can include other files for example rc def that you have created for graphical user interface GUI applications Specify the directory which contains the Traditional 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 Traditional NI DAQ header files are located in the Include directory under your NI DAQ directory Add the Traditional NI DAQ import library nidaq32 1ib to the project The Traditional NI DAQ import library files are located in the Lib directory under your NI DAQ directory Build your application You can find example programs and project files in Examples Visualc directory under your NI DAQ directory To load an example program use one of the g
97. he 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 6LXX 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 671X devices and 673X devices in NI DAQ 5 1 and later you can reduce or even eliminate the FIFO lag effect by specifying the FIFO condition Traditional NI DAQ uses to determine when to put more data into the FIFO Refer to the AO_Change_Parameter function in Traditional NI DAQ C Reference Help for details Externally Triggering Your Waveform Generation Operation You can initiate a waveform generation operation from an external trigger signal in much the same manner as for analog input Refer to the Select_Signal function in the Traditional NI DAQ C Reference Help 3 52 ni com Chapter 3 Software Overview 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 NJ DAQ Functions Listed by Hardware Product section of the Traditional NI DAQ C Reference Help to find out which digital functi
98. hese routines convert TCVolts or each element of TCVoltBuf 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 TCVolts into a corresponding 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 5 10 ni com Chapter 5 Transducer Conversion Functions Table 5 1 All the reference equations and inverse equations used in these routines are from NIST Monograph 175 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
99. hod 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 Traditional 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 1 0 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 devices with digital I O ports can use no handshaking digital port I O DIO 24 6025E devices AT MIO 16DE 10 and DIO 96 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 Traditional NI DAQ User Manual 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 y Input data from port y Output data to port DIG_In_Prt DIG
100. ial considerations Buffer Allocation Visual Basic 4 0 is 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 After 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 Traditional 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 Traditional 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 ay Note If you allocate memory from GlobalAlloc you must call GlobalLock on the memory object before passing it to Traditional NI DAQ The following paragraph illustrates declarations of fu
101. ication tips 3 31 input operations 4 2 potential setbacks 4 4 output operations 4 6 potential setbacks 4 7 overview 4 1 National Instruments Corporation l 5 Traditional NI DAQ User Manual Index E E Series devices Calibrate_E_Series function 3 4 counter usage 3 51 FIFO lag effect 3 51 RTSI bus connections 3 81 event counting 3 74 event message functions See also NI DAQ events in Visual Basic for Windows application tips 3 5 Config_Alarm_Deadband 3 5 Config_ATrig_Event_Message 3 5 Config _DAQ_ Event_Message 3 5 event procedures 3 6 example code A 1 external multiplexer support AMUX 64T 3 25 external triggering of waveform generation 3 52 EXTUPD signal 3 81 EXTUPDATE signal 3 81 F FIFO lag effect 3 51 frequency measurement 3 74 frequently asked questions A 1 functions analog input functions one shot analog input functions 3 16 single channel analog input application tips 3 17 single channel analog input functions 3 16 analog output functions application tips 3 36 list of functions 3 35 counter timer functions application tips 3 76 counter timer operation 3 74 Traditional NI DAQ User Manual l 6 general purpose counter timer functions 3 76 list of functions 3 76 data acquisition functions application tips 3 25 double buffered data acquisition application tips 3 31 high level data acquisition functions 3 20 low level data acquisition functions 3 22 low level double
102. in building Traditional NI DAQ applications and explains the basics of making applications using the following tools e Microsoft Visual C e Microsoft Visual Basic If you are not using the tools listed refer to your development tool reference manual for details on creating applications that call DLLs The Traditional NI DAQ Libraries 3 The Traditional NI DAQ function libraries are DLLs which means that Traditional NI DAQ routines are not linked into the executable files of applications Only the information about the Traditional NI DAQ routines in the Traditional NI DAQ import libraries is stored in the executable files Note Use the 32 bit nidaq32 d11 If you are programming in C or C link in the appropriate import library Refer to the following sections for language specific details Using function prototypes is a good programming practice That is why Traditional 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 Traditional NI DAQ works with you must create your own function prototype file National Instruments Corporation 2 1 Traditional NI DAQ User Manual Chapter 2 Fundamentals of Building Windows Applications Creating a Windows Application Using Microsoft Visual C This section assumes that you will be using t
103. ing as long as they keep pace with the DAQ device as in Figure 4 1 The second potential problem occurs when an input device overwrites data that Traditional NI DAQ is simultaneously copying to the transfer buffer Traditional NI DAQ returns an overwrite error overWriteError when this occurs The situation is presented in Figure 4 3 Incoming Device Data Y Circular Buffer i 0 a hv i b 7 KW i a e ma Transfer Buffer p Pa y r va ru Overwrite Error Empty Untransferred Transferred Corrupted Buffer Data Data Data Figure 4 3 Double Buffered Input with an Overwrite In Figure 4 3b Traditional NI DAQ has started to copy data from the first half of the circular buffer into the transfer buffer However Traditional 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 Traditional NI DAQ User Manual Chapter 4 Traditional 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 divid
104. ing the buffer into two halves Traditional NI DAQ can coordinate user access to the data buffer with the DAQ device The coordination scheme is simple Traditional 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 A Outgoing Device Data r wv Transfer Buffer FAG at Data Ready Successfully Empty Buff ieee for Output Output Data Circular Buffer Traditional NI DAQ User Manual Figure 4 4 Double Buffered Output with Sequential Data Transfers 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 Traditional NI DAQ can copy the prepared data from the transfer buffer to the first half of the circular buffer Figure 4 4b Your application then can update the data in the transfer buffer After the output device is finished 4 6 ni com Chapter 4 Traditional NI DAQ Double Buffering 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 Traditional NI DAQ can now copy the transfer buffer to the second half of the circular buffer Figure 4 4c
105. input functions analog output application tips equivalent analog output calls figure 3 36 SCXI applications 3 102 simple application 3 37 software update application 3 37 analog output devices reference voltages for tables 3 50 analog output functions See also waveform generation functions AO_Change_Parameter 3 35 AO_Configure 3 35 AO_Update 3 35 AO_VScale 3 35 AO_VWrite 3 36 AO_ Write 3 36 Analog Trigger Event control properties table 3 9 setting properties 3 9 AO_ Calibrate function 3 3 AO_Change_Parameter function 3 35 Traditional NI DAQ User Manual Index AO_Configure function 3 35 AO_Update function 3 35 AO_VScale function 3 35 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 reference voltages for waveform generation tables 3 50 AT MIO 16DE 10 groups of ports 3 55 buffer allocation in Windows applications Microsoft Visual Basic 2 5 Microsoft Visual C 2 3 building Windows applications Microsoft Visual Basic 2 3 Microsoft Visual C 2 2 NI DAQ examples 2 8 NI DAQ libraries 2 1 C Calibrate _1200 function 3 3 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 sample use cases 3 78 synchronization
106. ins the voltages that Traditional 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 t3 For temperatures above 0 C the C coefficient is 0 and the equation reduces to a quadratic equation for which we have found the appropriate root Thus these conversion routines are accurate only for temperatures above 0 C Your RTD documentation should give you Rg 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 EN 60751 standard or the American curve The values for A and B are as follows e European Curve DIN EN 60751 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 103 B 5 8408 x 10 7 a 3 92 x 10 3 1 492 Some RTD documentation contains values for a and 0 from which you can calculate A and B using the following equations A a 1 9 100 B a0 10 000 1007 National Instruments Corporation 5 3 Traditional NI DAQ User Manual Chapter 5 Transducer Conversion Functions where is the temperature coe
107. ion 3 76 GPCTR_Watch 3 76 Get_DAQ_Device_Info function 3 2 Get_NI_DAQ Version function 3 2 GPCTR_Change_Parameter function 3 76 4 10 GPCTR_Config_Buffer function 3 76 GPCTR_Control function 3 76 GPCTR_Read_Buffer function 3 76 4 11 4 12 GPCTR_Set_Application function 3 76 GPCTR_Watch function 3 76 National Instruments Corporation l 7 Index group digital I O functions 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 DIG_In_Grp 3 58 DIG_Out_Grp 3 58 DIG_SCAN_Setup 3 58 DIG_Trigger_Config 3 59 group digitial I O applications digital double buffered group block T O 3 59 digital group block I O 3 68 digital group I O 3 67 groups of ports 653X group 3 55 DIO 24 6025E AT MIO 16DE 10 and DIO 96 3 55 PCI 6115 6120 and 673X groups 3 56 H handshaking mode 3 55 handshaking versus no handshaking digital T O 3 63 help professional services A 1 technical support A 1 high level data acquisition functions See also data acquisition application tips DAQ_Op 3 20 DAQ _to_Disk 3 21 Lab_ISCAN_Op 3 21 Lab_ISCAN_to_Disk 3 21 SCAN_Op 3 21 SCAN_to_Disk 3 21 Traditional NI DAQ User Manual Index high level waveform generation functions WFM_from_Disk 3 39 WFM_Op 3 39 Init_DA_Brds function 3 2 initialization and general configuration functions Align _DMA_Buffe
108. ion indicating when an input operation has been latched to or 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 Traditional NI DAQ C Reference Help 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 DIG_Out_Prt Writes digital output data to the specified digital port DIG_Prt_Config Configures the specified port for direction input or output DIG_Prt_S
109. k National Instruments Data Acquisition Library If you do not see it listed there click the Browse button and locate nidaq32 d11 in your Windows system or Windows system32 directory 4 Run your application by clicking the Run button B 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 refer to the Traditional NI DAQ Events in Visual Basic section of Chapter 3 Software Overview Refer to the Traditional NI DAQ reference help files for more information on using the Traditional NI DAQ functions in Visual Basic for Windows Example Programs You can find example programs and project files in the Examples VBasic directory under your Traditional 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 version 4 0 or later Traditional NI DAQ User Manual 2 4 ni com Chapter 2 Fundamentals of Building Windows Applications To load an example project with Visual Basic 4 0 or later versions select the menu option File Open Project then select the vbp file of your choice Special Considerations When developing an application using Visual Basic consider the following spec
110. l clock You see a lag effect for group channels because of the FIFO National Instruments Corporation 3 51 Traditional NI DAQ User Manual Chapter 3 Software Overview Traditional NI DAQ User Manual 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 Three functions are affected by the FIFO lag effect wFmM_Chan_Control WFM_Check and double buffered waveform generation e WFM_Chan_Control When you execute operation PAUSE for a group channel the effective pause does not occur until the FIFO has finished writing all of the data remaining in the FIFO for the specified channel The same is true for the RESUME operation on a group 1 channel Traditional 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 Traditional NI DAQ has written to the FIFO for the specified channel A time lag occurs from the point when Traditional NI DAQ writes the data to the FIFO when Traditional 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 t
111. l 3 42 ni com Chapter 3 Software Overview j 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 WFM_Load Convert output rate to timebase and interval Yes Iterations gt 0 WFM_Rate Set the update rate No WFM_ClockRate or WFM_Set_Clock Start background waveform generation WFM_Group_Control operation START g WFM_Check Any more data to output Clear waveform WFM_Group_Control operation CLEAR Figure 3 15 Basic Waveform Generation Application National Instruments Corporation 3 43 Traditional NI DAQ User Manual Chapter 3 Software Overview Traditional NI DAQ User Manual 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
112. l NI DAQ installer places all of these ActiveX controls in the NIDAQ subdirectory of your Windows 2000 NT XP Me 98 directory under the file names shown These three ActiveX controls actually call the Traditional 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 Traditional NI DAQ ActiveX controls shown previously in this section your Visual Basic application can receive Traditional NI DAQ messages iy 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 Refer to the Event Message Functions section for a complete description of Traditional 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 1 n default ChanStr Refer to Config_DAQ_Event_Message in the Traditional NI DAQ C Reference Help DAQEvent 0 Acquired or generated n scans 1 Every n scans 2 Completed operation or stopped by error 3 Voltage out of bounds 4 Voltage within bounds 5 Analog positive slope triggering 6 Analog negative slope triggering
113. latencies associated with getting the data from system memory to the DAQ device refers to a high speed external bus that implements the JEEE 1394 serial bus protocol G 6 ni com gain group GPS GPS receiver GUI T O ID IDE IEEE import library interrupt interrupt latency IRIG IRQ National Instruments Corporation G 7 Glossary 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 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 receive
114. m DAQ_to_Disk Lab_ISCAN_Op Lab_ISCAN_to_Disk SCAN_Op SCAN_to_Disk National Instruments Corporation 3 21 Chapter 3 Software Overview not return until Traditional 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 Traditional 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 Traditional 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 Traditional NI DAQ has acquired all the data and saved all the data or an acquisition error has occurred Performs a synchronous multiple channel scanned data acquisition operation SCAN_Op does not return until Traditional 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 SCAN_to_Disk does not return until Traditional NI DAQ has acquired all the data and saved it or until an acquisition error has occurred Traditional NI D
115. 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 7 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 National Instruments Corporation 3 81 Traditional NI DAQ User Manual Chapter 3 Software Overview Table 3 7 653X RTSI Bus Signals Signal Direction Signal Direction Handshaking Signal Direction Signal Name Pattern Direction No Pattern Generation No Handshaking Signal Code REQI 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 STOPTRIGI1 Receiver Unused Receiver 4 STOPTRIG2 Receiver Unused Receiver 5 PCLK1 Unused Source internal clock or Source 6 receiver external clock PCLK2
116. ments Corporation 3 13 Traditional NI DAQ User Manual Chapter 3 Software Overview Traditional NI DAQ User Manual To place the GeneralDAQEvent control into your form go to the tool box window and select the GeneralDAQEvent tool labelled DAQ EVENT 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 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 Refer to the function description for Set_DAQ_Device_Info in the Traditional NI DAQ C Reference Help for more information You also must 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 DAQTrigVal0 1000 set N 1000 scans GeneralDAQEvent1 Enabled True Next start an asynchronous operation Use the Traditional NI DAQ function DAQ_Start Set up your program so it does aDAQ_Start on channel 0 when you click a button yo
117. 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 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 Resistive Temperature Detector a metallic probe that measures temperature based upon its coefficient of resistivity G 10 ni com RTSI S s s S Sample and Hold S H 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 module SDK National Instruments Corporation G 11 Glossary Real Time System Integration bus the National Instrument
118. mples 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 e A single source code file to illustrate the task at hand e A library of Traditional NI DAQ example utility functions for buffer creation waveform plotting error checking and implementing a delay Sy 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 Traditional NI DAQ User Manual 2 8 ni com Chapter 2 Fundamentals of Building Windows Applications DI Digital Input examples DO Digital Output examples CTR Counter timer examples SCXI SCXI examples CALIB Calibration examples 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 frm form module
119. n CLEAR operation PAUS waveform generator Figure 3 16 Waveform Generation with Pauses Traditional NI DAQ User Manual 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 Traditional 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 generation 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 assign an update rate to a gr
120. n 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 Traditional NI DAQ logically divides the buffer into two equal halves no actual division exists in the buffer By dividing the buffer into two halves Traditional NI DAQ can coordinate user access to the data buffer with the DAQ device The coordination scheme is simple Traditional 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 Traditional NI DAQ User Manual 4 2 ni com Chapter 4 Traditional NI DAQ Double Buffering Figure 4 1 illustrates a series of sequential data transfers Incoming Device Data Circular Buffer a KV b 5 Transfer Buffer a A z 1 v1 2 oan z 4 c JN z 2 J lt 7 2 r r d z r G a 2 1 gt a 2 j Pid A AJ
121. n 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 Traditional 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 wrM_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 begins 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 Traditional 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 Refer to the Double Buffered Waveform Generation Applications section for more information The second option to start a waveform generation i
122. nctions 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 National Instruments Corporation 2 5 Traditional NI DAQ User Manual Chapter 2 Traditional NI DAQ User Manual Fundamentals of Building Windows Applications Lib kernel32 Alias Long As Long Lib kernel32 Alias Long ByVal dwBytes As Long Lib kernel32 Long As Long Declare Function GlobalLock GlobalLock ByVal hMem As Declare Function GlobalReAlloc GlobalReAlloc ByVal hMem As Long ByVal wFlags As Long As Declare Function GlobalUnlock Alias GlobalUnlock ByVal hMem As String Passing In Visual Basic variables of data type String need no special modifications to be passed to Traditional NI DAQ 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 Passing Unsigned 16 Bit and 32 Bit Integer Parameters The Visual Basic INTEGER type is a signed value Visual Basic considers any value greater than 32 767 a negative number To pass unsigned 16 bit
123. nes 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 3 54 ni com Chapter 3 Software Overview You can use digital I O ports on the DIO 24 6025E devices DIO 96 653X DIO 32F 673X PCI 6115 and 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 ou
124. nfig 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 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 to or from the circular buffer call the DIG_DB_Transfer function After you call the function Traditional NI DAQ waits until it can transfer the data before returning to the application To avoid the waiting period call DIG_DB_Hal fReady to determine if Traditional NI DAQ can make the transfer immediately If DIG_DB_HalfReady indicates that Traditional 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 Traditional NI DAQ requires some time after the final transfer to actually output the data In addition if Traditional NI DAQ completes the block operation prior
125. ng For digital block input and output operations call DIG_DB_Config prior to calling DIG_Block_In or DIG_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_Doub1e Counters transfer their data continuously not in half buffers Double 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 3 Note Waveform transfer functions do not detect overwrite before copy or overwrite errors Traditional NI DAQ User Manual 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 Traditional NI D
126. ng 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 Check ongoing single or multiple channel data acquisition status DAQ_Check Data Acquisition complete Figure 3 8 Buffered Data Acquisition Application Building Block 3 Checking for the MIO Al and DSA Devices Yes Sample multiple channels Check ongoing multiple Check ongoing single channel data acquisition channel data acquisition status status Vv Lab_ISCAN_Check DAQ_Check Figure 3 9 Buffered Data Acquisition Application Building Block 3 Checking for the LPM Devices 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 Traditional NI DAQ User Manual 3 30 ni com Chapter 3 Software Overview process but you can also retrieve a portion 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 d
127. ng AO_vwrite However substituting the equivalent AO_VScale and AO_Write calls will not change the results Traditional NI DAQ User Manual 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 a y Output voltage to board AO_VWrite y 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 or AT AO 6 10 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 or to the selected pin on an E Series 671X or 673X 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
128. nous data acquisition operation Call any one of the four following procedures e AnalogAlarm_HighAlarmOn e AnalogAlarm_HighAlarmoff AnalogAlarm_LowAlarmOn 2 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 3 12 ni com Chapter 3 Software Overview The parameter DoneFlag equals 1 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 sec
129. olar output polarity table 3 50 REQ signal 653X RTSI connections table 3 82 REQ signal 653X RTSI connections table 3 82 RTD_Buf_Convert function 5 2 RTD_Convert function definition 5 1 Traditional NI DAQ User Manual purpose and use 5 2 RTSI bus application tips 3 83 description 3 80 RTSI bus connections 653X 3 81 E series DSA 660X 67 LX and 673X 3 81 RTSI bus trigger functions RTSI_Clear 3 80 RTSI_Clock 3 80 RTSI_Conn 3 80 RTSI_DisConn 3 80 Select_Signal 3 80 S SCAN_Demux function 3 23 SCAN_Op function 3 21 SCAN_Sequence_Demux function 3 23 3 33 SCAN_Sequence_Retrieve function 3 23 3 33 SCAN_Sequence_Setup function 3 23 3 33 SCAN_Setup function 3 24 SCAN_Start function 3 24 SCAN_to_Disk function 3 21 SCXI application tips analog output applications 3 102 data acquisition rates 3 100 digital applications 3 102 general SCXIbus application flowchart 3 89 Multiplexed mode 3 90 Parallel mode 3 96 settling times table 3 101 SCXI functions SCXI_AO_ Write 3 84 SCXI_Cal_Constants 3 85 SCXI_Calibrate 3 85 SCXI_Calibrate_Setup 3 85 ni com SCXI_Change_Chan 3 86 SCXI_Configure_Connection 3 86 SCXI_Configure_Filter 3 86 SCXI_Get_Chassis_Info 3 86 SCXI_Get_Module_Info 3 86 SCXI_Get_State 3 86 SCXI_Get_Status 3 86 SCXI_Load_Config 3 86 SCXI_ModuleID_Read 3 87 SCXI_MuxCtr_Setup 3 87 SCXI_Reset 3 87 SCXI_Scale 3 87 SCXI_SCAN_Setup 3 87 SCXI_S
130. onal Instruments Corporation G 13 Traditional NI DAQ User Manual Index Numerics 4451 and 4551 devices counter usage 3 51 FIFO lag effect 3 51 6025E groups of ports 3 55 6115 and 6120 devices See PCI 6115 and 6120 devices 652X devices digital change notification applications 3 60 653X devices digital change detection applications 3 61 groups of ports 3 55 pattern generation 3 72 RTSI connections 3 81 660X devices RTSI connections 3 81 671X devices counter usage 3 51 FIFO lag effect 3 51 RTSI connections 3 81 673X devices counter usage 3 51 FIFO lag effect 3 51 RTSI connections 3 81 A ACK1 signal 653X RTSI connections table 3 82 ACK2 signal 653X RTSI connections table 3 82 ActiveX controls for Visual Basic 3 6 AI device terminology table x AI_Change_Parameter function 3 16 AI_Check function 3 16 AIL_Clear function 3 16 AI_Configure function 3 16 National Instruments Corporation AI_Mux_Config function 3 16 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 AMUX 64T external multiplexer support 3 25 Analog Alarm Event control properties table 3 11 setting program flow 3 12 setting properties 3 12 analog input application tips See data acquisition application tips analog input functions See data acquisition functions one shot analog
131. ond element has Index 1 and so on 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 GeneralDAQEvent custom control e Ifyou are using Visual Basic 5 0 select the Project Components option and select the National Instruments GeneralDAQEvent custom control In either version if you do not find the custom control listed click the Browse button and find the custom control in the NI DAQ subdirectory under your Windows directory National Instru
132. ons 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 ports 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 653X devices for example you can assign any of the ports DIOA through DIOD to one of two groups On the PCI 6115 PCI 6120 and 673X devices you also can 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 line
133. orm Buffer Device 2 048 2 047 32 768 32 767 AT MIO 16XE 10 Negative of Reference PCI MIO 16XE 10 the reference voltage PCI MIO 16XE 50 voltage PCI 6031E MIO 64XE 10 PCI 6110 PCI 6111 6052E devices All other MIO devices Negative of Reference 671X devices the reference voltage voltage AT AO 6 10 Negative of Reference the reference voltage voltage 10 V in 10 V in default case default case 673X devices Negative of Reference the reference voltage voltage Traditional NI DAQ User Manual 3 50 ni com Chapter 3 Software Overview B Note NI PCI 4451and NI PCI 4551 devices use signed 18 bit binary data left justified in 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 Traditional NI DAQ Double Buffering for more information on the minimum update intervals Counter Usage NI PCI 4451 and NI PCI 4551 devices use the same counter for
134. oup of analog output channels Refer to the Traditional NI DAQ C Reference Help for the function that supports your device Calling WwrM_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 Traditional 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 Traditional NI DAQ is not ready for a transfer your application is free to do other processing and check the status later National Instruments Corporation 3 47 Traditional NI DAQ User Manual Chapter 3 Software Overview Traditional NI DAQ User Manual After the final transfer you can call WFM_Check to get the current transfer progress Remember Traditional NI DAQ requires some time after the final transfer to actually output the data The final step is to call WEM_Group_Control operation CL FAR The CLEAR operation performs all of the necessary cleanup work after a waveform generation Additionally CLEAR halts any ongoing waveform generation 3 48 ni com Chapter 3 Software Ove
135. parameters refer to the following examples e Ifthe function is supposed to return an unsigned 16 bit integer and you are reading back a negative number add 65 536 to the negative number Dim myUnsignedCnt As Long Dim retCnt As Integer retCnt is the value returned from the called function You can call a DAQ function that returns an unsigned 16 bit value and store the value in retCnt if retCnt lt 0 then myUnsignedCnt CInt retCnt 65536 else myUnsignedCnt retCnt end if 2 6 ni com Chapter 2 Fundamentals of Building Windows Applications To pass an unsigned 16 bit value to a function with an unsigned 16 bit type parameter you must first compute the value to pass to the function Dim myUnsignedCnt As Long Dim ToPassVal As Integer You compute the value that you want to pass to the function and store it in myUnsignedCnt if myUnsignedCnt gt 32767 then ToPassVal CInt myUnsignedCnt 65536 else ToPassVal CInt myUnsignedCnt end if The Visual Basic LONG integer type is a signed 32 bit type Visual Basic considers any value greater than 2 147 483 647 a negative number To pass unsigned 16 bit parameters refer to the following examples National Instruments Corporation If the function is supposed to return an unsigned 32 bit integer and you are reading back a negative number then add 4 294 967 296 to the negative number Dim myUnsignedCnt As Double Dim retCnt As Long
136. perature 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 Nn nn A U N Hawas National Instruments Corporation 5 9 Traditional NI DAQ User Manual Chapter 5 Transducer Conversion Functions Traditional NI DAQ User Manual E B N CJCTemp is the temperature in Celsius that Traditional NI DAQ uses for cold junction compensation of the thermocouple temperature If you are using SCXI most likely this is the temperature that Traditional NI DAQ read from the temperature sensor on the SCXI terminal block The AMUX 64T also has a temperature sensor 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 TCVolts is the voltage that Traditional 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 Traditional NI DAQ read from the thermocouple and TCTempBuf is the return array that contains the temperatures Using This Function T
137. plication program The transducer conversion routine descriptions apply to all languages Function Descriptions RTD_ Convert and RTD_Buf_Convert Traditional NI DAQ User Manual These functions convert a voltage or voltage buffer that Traditional 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 routine 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 5 2 ni com Chapter 5 Transducer Conversion Functions The RTD_Convert routine has two remaining parameters RTD Volts is the voltage that Traditional NI DAQ reads 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 conta
138. quired you should see the text box display a completion message If you run into errors refer to the Traditional NI DAQ C Reference Help for guidance 10 Click 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 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 National Instruments Corporation 3 15 Traditional NI DAQ User Manual Chapter 3 Software Overview One Shot Analog Input Functions Single Channel Analog Input Functions Use the single channel analog input functions on the MIO and AI devices Refer to the Traditional NI DAQ C Reference Help to determine which functions your device supports AI_Check Returns the status of the analog input circuitry 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
139. r interrupt request Traditional NI DAQ User Manual Glossary ISA iterations J Julian kS Kword L linker LSB master slave MAX MB MIO MIO device Traditional NI DAQ User Manual MIO 16XE 50 device Industry Standard Architecture repetitions of the buffer 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 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 Measurement amp Automation Explorer megabytes of memory multifunction I O refers to multifunction I O devices refers to the AT MIO 16XE 50 and PCI 6070E PCI MIO 16XE 50 G 8 ni com MIO 64 MS MSB multirate scanning mux NI NI DAQ NI TIO based device NO 0 OCX output settling time P paging PC PCI National Instruments Corporation G 9 Glossary refers to the AT MIO 64E 3 PCI 6031E and PCI 6071E million samples most significant bit scannin
140. r 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 setting up your DAQ system 1 2 instrument drivers A 1 K KnowledgeBase A 1 L Lab_ISCAN_Check function 3 23 Lab_ISCAN_Op function 3 21 Lab_ISCAN_ Start function 3 23 Lab_ISCAN_to_Disk function 3 21 libraries NI DAQ 2 1 low level data acquisition functions application tips See data acquisition application tips DAQ_ Check 3 22 DAQ Clear 3 22 DAQ Config 3 22 DAQ Monitor 3 22 DAQ Rate 3 22 DAQ Set_Clock 3 22 DAQ Start 3 22 Traditional NI DAQ User Manual 1 8 DAQ StopTrigger_Config 3 22 DAQ_VScale 3 23 Lab_ISCAN_Check 3 23 Lab_ISCAN_ Start 3 23 SCAN_Demux 3 23 SCAN_Sequence_Demux 3 23 3 33 SCAN_Sequence_Retrieve 3 23 3 33 SCAN_Sequence_Setup 3 23 3 33 SCAN_Setup 3 24 SCAN_ Start 3 24 low level double buffered data acquisition functions 3 24 application tips See data acquisition application tips DAQ_DB_Config 4 10 DAQ_DB_HalfReady 3 24 4 11 DAQ_DB_ Transfer 3 24 4 11 low level waveform generation functions WFM_Chan_Control 3 39 3 52 WFM_Check 3 52 WEFM_ClockRate 3 39 WFM_DB_HalfReady 3 40 WFM_DB _ Transfer 3 40 WFM_Group_Control 3 40 WFM_Group_Setup 3 40 WFM_Load 3 40 WFM_ Rate 3 40 WFM_ Scale 3 40 WFM_Set_Clock 3 41 LPM devices See PC LPM 16 LPM16_Calibrate function 3 4 manual See documen
141. r 4 Traditional NI DAQ Double Buffering Outgoing Device Data T Circular Buffer i Transfer Buffer rd a 4 a e ua H for e P Overwrite Before A Copy Empty Buffer Untransferred Data Transferred Data Figure 4 5 Double Buffered Output with an Overwrite before Copy For this situation Traditional 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 Traditional NI DAQ is simultaneously overwriting with data from the transfer buffer Traditional NI DAQ returns an overwrite error overWriteError when this occurs The situation is presented in Figure 4 6 Traditional NI DAQ User Manual 4 8 ni com Chapter 4 Traditional NI DAQ Double Buffering Outgoing Device Data Circular Buffer Empty Buffer an al 7 a S V Te b Lv Cae 4 1 p 5 1 L Pes y a 7 2 mw Transfer Buffer a Overwrite Error Fa z 4 s A F z z z Data Ready Successfully Corrupted for Output Output Data Output Figure 4 6 Double Buffered Output with an Ove
142. raditional NI DAQ User Manual 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 functions Traditional
143. rameters strainVolts is the voltage that Traditional NI DAQ read from the strain gage 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 Traditional 5 4 ni com Chapter 5 Transducer Conversion Functions NI DAQ read from the strain gage and strainValBuf is the return array that contains the strain values Using This Function The conversion formula used is based solely on the bridge configuration Figure 5 1 shows the seven bridge configurations supported and the corresponding formulas For all bridge configurations Traditional NI DAQ uses the following formula to obtain V _ SstrainVolts V init i 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 Ry and R are dummy resistors that are not directly incorporated into the conversion formula The SCXI 1121 and SCXI 1122 modules provide R and R for a bridge completion network if needed Refer to the Getting Started with SCXI user manual for more information on bridge completion networks and voltage excitation National Instruments Corporation 5 5 Traditional NI DAQ User Manual Chapter 5 Transducer Conversion Functions bridgeConfig 1 QTR
144. rate for the PCI 6032E would be __ 99 9ks s 10 us 1 us 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 3 100 ni com Chapter 3 Table 3 8 Maximum SCXI 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 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 ps 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 ps 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 effec
145. rd y SCXI_Track_Hold_Setup y Figure 3 35 Channel Scanning Operation Using an SSH Module in Parallel Mode The call sequence is much simpler because the scan interval timer automatically controls the Track Hold state of the module during the National Instruments Corporation 3 99 Traditional NI DAQ User Manual Chapter 3 Software Overview Traditional NI DAQ User Manual interval scanning operation Remember that only the MIO and AI devices work with channel scanning using an 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 8 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 ae 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
146. roup ssessesesseerssrsrsresrsresresesrrstststerrntestesrsresresrntesreeeseentnees 3 74 Counter Timer Operation for the GPCTR Functions esseeeeseeeeeeeeeesreereeeees 3 74 General Purpose Counter Timer Functions ssessereseeesseerrrrsrrsrsrrsrsrrsrerese 3 76 General Purpose Counter Timer Application Tips eseeeeseeeserrsesesersrsrrereer 3 76 Clocks or Time Counters ices cossededcany ssatecescnevdeadea E NEER ASS 3 78 Sample Use Cases iiir easar sscestaseosuas ssdsgssscabseoutsaddevecaseevas 3 78 Use Case 1 x ssectesieientectesvs spielen sssuncvsvicue VEEE E E EEEE 3 78 USE Case H2 wesc oi iara p ara E E EATA Ta 3 78 RTSI Bus Trigger Functions s in aia 3 79 RIS Buss siges sesctet egg scsi ca Moses tleg dedi se eaaa E R AE Stadia Sahai ieee 3 80 E Series DSA 660X 671X and 673X RTSI Connections cccceeeeeeeeeees 3 81 653X REST Commectns isseire a si Ea aiia a 3 81 RTSI Bus Application Tips 0 eee ee eee eseeseceeceseceeeeseeeeesecseeeaeeeseaeeseeeaeeaes 3 83 SCXE PUNCHONS ii 0 45 Aisi dsiidtialiteieeaeesosaiaits ssa E bikie se aein die Av eee 3 84 SCX Application TIPS esena ai bestia ei E E RER 3 89 Building Analog Input Applications in Multiplexed Mode 3 90 Building Analog Input Applications in Parallel Mode 00 3 96 SCXI Data Acquisition Rates 0 cece eee cssceeeseeeeeseeeeseeseeeseeaeees 3 100 Analog Output Applications eee ce ceeeseceeeeseeeseeseceeeeaeenseeaesneeeaeenaeae
147. rrors 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 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 rea
148. rs and include software drivers and updates a KnowledgeBase product manuals step by step troubleshooting wizards hardware schematics and conformity documentation example code tutorials and application notes instrument drivers discussion forums a measurement glossary and so on Assisted Support Options Contact NI engineers and other measurement and automation professionals by visiting ni com ask Our online system helps you define your question and connects you to the experts by phone discussion forum or email e Training Visitni com custed for self paced tutorials videos and interactive CDs You also can register for instructor led hands on courses at locations around the world e System Integration lIf you have time constraints limited in house technical resources or other project challenges NI Alliance Program members can help To learn more call your local NI office or visit ni com alliance If you searched ni com and could not find the answers you need contact your local office or NI corporate headquarters Phone numbers for our worldwide offices are listed at the front of this manual You also can visit the Worldwide Offices section of ni com niglobal to access the branch office Web sites which provide up to date contact information support phone numbers email addresses and current events National Instruments Corporation A 1 Traditional NI DAQ User Manual Glossary
149. rview y Enable double buffering WFM_DB_Config y Assign channels to waveform generation group WFM_Group_Setup y Load waveform buffer and specify iterations WFM_Load y Set the update rate FM_ClockRate or WFM_Set_Clock Start background waveform generation WFM_Group_Control operation START gt 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 No Any more data to output Clear the waveform WFM_Group_Control operation CLEAR Figure 3 17 Double Buffered Waveform Generation National Instruments Corporation 3 49 Traditional NI DAQ User Manual 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 Waveform Buffer Device 0 4 095 65 535 AT MIO 16XE 10 PCI MIO 16XE 10 OV Reference voltage PCI MIO 16XE 50 PCI 6031E MIO 64XE 10 6052E devices All other MIO devices OV Reference voltage 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 Wavef
150. rwrite In Figure 4 6b Traditional NI DAQ has started to copy data from the transfer buffer to the first half of the circular buffer However Traditional 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 transfers 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 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 National Instruments Corporation 4 9 Traditional NI DAQ User Manual Chapter 4 Traditional NI DAQ Double Buffering The configuration functions are as follows e DAQ_DB_ Config WFM_DB_Config DIG_DB_Config s 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 bufferi
151. ry value directly to the DAC channel or to translate a voltage or current value to the corresponding binary value Calculates 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 Traditional 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 SCX I 1540 modules With the SCXI 1112 and SCXI 1125 calling 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 Traditional 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 supports shunt calibration for the SCXI 1122 module or the SCXI 1121 mod
152. s Use AI_VScal1e to convert the binary National Instruments Corporation Traditional NI DAQ User Manual Chapter 3 Software Overview values to voltages at a later time if you want Refer to Figure 3 1 for the function flow typical of single point data acquisition Also refer to the NI DAQ Examples Online Help nidagex h1p to find a related example When using SCXI as a front end for analog input to the MIO and AI 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 Traditional NI DAQ User Manual 3 18 ni com Chapter 3 Software Overview Change analog input y default configuration AI_Configure Add AMUX 64T configuration y AI_Mux Config gt y Yes No Binary reading Retrieve an analog Retrieve an analog reading in terms of a reading in terms of binary value y voltage AI_Read AI_VRead Yes Another reading Figure 3 1 Single Point Analog Reading with Onboard Conversion Timing When accurate sample timing is important you can use external conversion pulses with AI_Clear AI_Setup and AI_Check to sample your signal on the analog input channels Refer to Figure 3 2 for the function
153. s 0 cevatescesev castes svete centers n 3 11 Analog Input Function Group iesise tea EARR E ER 3 15 One Shot Analog Input Functions ssssssesssssessessseesesesestrersresresreresreresresenresre 3 16 Single Channel Analog Input Functions 000 00 eeeeseeseereeeeee 3 16 Data Acquisition FUnctions cece esceceeseceseeseceeecseeesessecseeeaseneseatensenaes 3 20 High Level Data Acquisition Functions 000 0 cece eeeeseereeeeeeeees 3 20 Low Level Data Acquisition Functions ce eeeeeeseeeeeseeeeeesees 3 22 Low Level Double Buffered Data Acquisition Functions 3 24 Data Acquisition Application Tips eee eee eeeeeseceeceeeseeenees 3 25 Mulltirate Scanning soenan E E rena 3 32 Analog Output Function Group cece eeceseesscesesseceseeeeesesseceseeseeeseeasceeecsesneeeseenaes 3 35 One Shot Analog Output Functions ccc eseeseeseceeeeeeeeetseseeeeeeseees 3 35 Analog Output Application Tips eee sees eeseeseeeseeseeeseeseees 3 36 Waveform Generation Functions 200 0 cece eeeeeseeseceseeeeesecseeneeeaeseeeeseeaees 3 39 High Level Waveform Generation Functions 00 0 0 eeeeeeeeeeees 3 39 Low Level Waveform Generation Functions 0 eeeeeeeeeeeeees 3 39 Waveform Generation Application Tips oe eee eeeeereeeeees 3 41 Digital VO Function Group sssi scectdscouessasnvevsetevs susvbeosnossuvacsesttoreutesnseveuces E ASE 3 53 DIO 24 6025E AT MIO 16DE 10 and DIO 96 Device Groups
154. s 3 102 Digital Applications sic si5 3is azelss coven nnne a a attaches 3 102 Chapter 4 Traditional NI DAQ Double Buffering OVERVI CW indeasiaiivecsasbecscvanens ged EA cdots oa leu sh subek des SUasdeevenbeittuvaaods E e ESEE 4 1 Single Buffered versus Double Buffered Data seseeessereseerseeeresesesrsresresrsresrsersresre 4 1 Double Buffered Input Operations sseessessesessesrsesteetsrestsrestsesresrsrenresesresrsreseeneneeses 4 2 Potential Setbacks nuina a a ed ine Ae waa 4 4 Double Buffered Output Operations 20 0 eee eee eeeeeeceeesseeseceseeseeeeecaseesecaeeneeeaeenees 4 6 Potential Setbacks ccssesciscivecezelceienicucbaldevsnnchadeavhcdestsageaceenedvegesecossteesaaves bovine 4 7 Double Buffered Functions dsm oeer leesett iee aae e e aE Er i e a ie 4 9 Double Buffer Configuration Functions esseeseseesseersersresrsrrsresesresrsresresree 4 9 Double Buffer Transfer Functions eseesseseeesesseesesesessrssessesseesressessessessesse 4 10 Double Buffer HalfReady Functions esseessessseessseersrrsrsresresrrsesrsresrrerereste 4 11 CONCIUSION ords ee E E a E E a a a asea 4 12 National Instruments Corporation vii Traditional NI DAQ User Manual Contents Chapter 5 Transducer Conversion Functions Function Descriptions s s 3 5 c8 c4scsebesessgeestoncaasi nn n a a TS 5 2 RTD_Convert and RTD_Buf_Convett sssesssssessserererrrrrrrsrsssesesssrsererrrrreeeee 5 2 Parameter DiSCUSSION
155. s as an output group A group of ports are handshaked or clocked as a unit National Instruments Corporation 3 53 Traditional NI DAQ User Manual Chapter 3 Software Overview Traditional NI DAQ User Manual 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 Traditional NI DAQ writes a byte of data to the port in a specified digital output pattern To read from a port Traditional 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 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 653X DSA 671X 673X 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 li
156. s for all analog input channels selected by Scan_Setup Returns readings in volts for analog input channels selected by Scan_Setup Selects the specified analog input channel and gain setting for externally pulsed conversion operations 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 Converts the binary result from an AI_Read call to the actual input voltage Single Channel Analog Input Application Tips All of the Traditional NI DAQ functions described in this section are for nonbuffered single point analog input readings For buffered data acquisition refer to the Data Acquisition Functions section 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 Traditional 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 Traditional 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 unscaled data is sufficient or when extra time taken by AI_VRead to scale the data is detrimental to your application
157. s 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 refers to the SCXI 1102 SCXI 1102B and SCXI 1102C refers to the SCXI 1120 and SCXI 1120D 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 SCXJ 1124 module refers to the SCXI 1000 SCXI 1000DC and SCXI 1001 refers to the SCXI 1160 SCXI 1161 SCXI 1162 SCXI 1162HV SCXI 1163 and SCXI 1163R refers to the SCXI 1127 SCXI 1128 SCXI 1129 SCXI 1160 SCXI 1161 SCXI 1163R SCXI 1190 SCXI 1191 and SCXI 1192 Software Development Kit Traditional NI DAQ User Manual Glossary self calibrating simultaneous sampling module Single Ended SE Inputs slave software trigger stage STC synchronous T TC throughput rate track and hold module Traditional NI DAQ transfer rate TSR Traditional NI DAQ User Manu
158. s to call the following sequence of functions 1 WFM_Group_Setup 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 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 National Instruments Corporation 3 41 Traditional NI DAQ User Manual Chapter 3 Software Overview it cannot return an error if you use it with a non supported device Refer to the Traditional NI DAQ C Reference Help for supported devices 4 WFM_ClockRate or WFM_Set_Clock to set the update rate Refer to the Traditional NI DAQ C Reference Help to find out which function supports your device 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 WEM_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 Traditional NI DAQ User Manua
159. sage external trigger FIFO FireWire Traditional NI DAQ User Manual refers to the PCI 4451 PCI 4452 PCI 4454 PCI 4472 PCI 4551 PCI 4552 PXI 4472 and PCI 4474 dynamic signal acquisition devices 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 refers to MIO and AI devices 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 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
160. so 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 Traditional NI DAQ User Manual 3 68 ni com Chapter 3 Software Overview Configure DIO 32F DIO 6533 DIO 32HS PCI 6115 PCI 6120 and 673X device groups for input and output DIG_Grp_Config Configure DIO 24 6025E devices AT MIO 16DE 10 or DIO 96 for input or output DIG_Grp_Mode DIG_Scan_Setup DIO 32F and DIO 6533 Enable or disable pattern generation Alter handshaking mode DIG_Block_PG_Config Enable or disable start and stop triggers DIG_Trigger_Config DIO 6533 only Start block input Start block output DIG_Block_In DIG_Block_Out Any more data to input or output Yes DIG_Block_Check Clear block operation if DIG_Block_Check did not DIG_Block_Clear Figure 3 24 Digital Block Input or Output Application Sy Note The 653X DIO 24 6025E devices AT MIO 16DE 10 and DIO 96 all can perform group block operations However the DIO 24 6025E devices AT MIO 16DE 10 and DIO 96 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 653X devices National Instruments Corporation 3 69
161. 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 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 Traditional NI DAQ User Manual Glossary byte C C CI cold junction compensation compiler conversion time counter timer coupling CPU D D A DAC DAQ Traditional NI DAQ User Manual eight related bits of data an 8 bit binary number Also used to denote the amount of memory required to store one byte of data Celsius computing index a method of compensating for inaccuracies in thermocouple circuits a
162. 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 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 devices in the same computer G 4 ni com DC DDS device differential input digital port DIN DIO DIO device DIO 24 DIO 32F DIO 96 dithering DLL DMA driver DSA National Instruments Corporation G 5 Glossary direct current Direct Digital Synthesis a plug in DAQ board c
163. sonable 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 prior written consent of National Instruments Corporation Trademarks CVI DAQCard DAQPad LabVIEW National Instruments NI ni com NI DAQ RTSI and SCXI are trademarks of National Instruments Corporation FireWire is a trademark of Apple Computer Inc Other product and company names mentioned herein are trademarks or trade names of their respective companies Patents For patents covering National Instruments products refer to the appropriate location Help Patents in your software the patents txt file on your CD or ni com patents 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
164. ss data simultaneously Traditional NI DAQ can transfer data using DMA interrupts or software polling Traditional NI DAQ can use DMA to transfer data into memory above 16 MB even on ISA bus computers With the 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 Traditional NI DAQ User Manual Chapter 1 Introduction to Traditional NI DAQ Traditional 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 Traditional 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 e When a rising or falling edge occurred on a timing I O line How to Set Up Your DAQ System Refer to the DAQ Quick Start Guide for NI DAQ 7 0 for more information on installing and configuring your hardware and software Traditional NI DAQ Overview Traditional NI DAQ is a library of routines that work with National Instruments DAQ devices Traditional NI DAQ helps you perform tasks ranging from simple device initialization to advanc
165. ssional Services appendix To comment on the documentation send email to techpubs ni com 1991 2003 National Instruments Corporation All rights reserved Important Information Warranty The media on which you receive National Instruments software are warranted not to 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 e
166. 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 Traditional NI DAQ Events in Visual Basic 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 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 Traditional NI DAQ ActiveX controls for Visual Basic applications e General Data Acquisition Event daqevent ocx e Analog Trigger Event atrigev ocx e Analog Alarm Event alarmev ocx Traditional NI DAQ User Manual 3 6 ni com Chapter 3 Software Overview The Traditiona
167. tation Measurement amp Automation Explorer application 1 2 Microsoft Visual Basic for Windows building Windows applications buffer allocation 2 5 example programs 2 4 ni com parameter passing 2 6 procedure 2 4 string passing 2 6 NI DAQ events ActiveX controls 3 6 Analog Alarm Event control 3 11 Analog Trigger Event control 3 9 General DAQ Event controls 3 7 General DAQ Event example 3 8 using multiple controls 3 13 special considerations 2 5 Microsoft Visual C building Windows applications 2 2 example programs 2 2 special considerations 2 3 MIO devices counter usage in waveform generation 3 51 FIFO lag effect 3 51 MIO and AI device terminology table x reference voltages for waveform generation table 3 50 MIO_Config function 3 4 MIO E series devices See E series devices Multiplexed mode applications SCXI 3 90 multiplexer device AMUX 64T 3 25 multirate scanning flow chart for 3 34 functions for 3 33 purpose and use 3 32 National Instruments customer education A 1 professional services A 1 system integration services A 1 technical support A 1 worldwide offices A 1 National Instruments Corporation l 9 Index NI 4551 devices counter usage 3 51 FIFO lag effect 3 51 NI DAQ events in Visual Basic for Windows ActiveX controls 3 6 Analog Alarm Event control 3 11 Analog Trigger Event control 3 9 General DAQ Event controls 3 7 General DAQ Event example 3 8 using multiple
168. tatus Returns a status word indicating the handshake status of the specified port National Instruments Corporation 3 57 Traditional NI DAQ User Manual Chapter 3 Software Overview Group Digital 1 0 Functions The Group Digital I O DIG_Block DIG_Grp and DIG_SCAN functions perform handshaked I O on groups of ports Refer to the Traditional NI DAQ C Reference Help to determine which functions your device supports DIG_Block_Check Returns the number of items remaining to be transferred after a DIG_Block_In or DIG_Block_Out call DIG_Block_Clear Halts any ongoing asynchronous transfer allowing another transfer to be initiated DIG _Block_In Initiates an asynchronous data transfer from the specified group to memory DIG_Block_Out Initiates an asynchronous data transfer from memory to the specified group DIG_Block_PG_Config Enables or disables the pattern generation mode of buffered digital I O DIG_Grp_Config Configures the specified group for port assignment direction input or output and size DIG_Grp_Mode Configures the specified group for handshake signal modes DIG_Grp_Status Returns a status word indicating the handshake status of the specified group DIG_In_Grp Reads digital input data from the specified digital group DIG_Out_Grp Writes digital output data to the specified digital group DIG_SCAN_Setup Configures the specified group for port assignment direction input or output and size
169. ter 3 Software Overview NI DAQ includes three functions for multirate scanning SCAN_Sequence_Setup e SCAN_Sequence_Retrieve s 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 Traditional NI DAQ functions National Instruments Corporation 3 33 Traditional NI DAQ User Manual Chapter 3 Software Overview Convert sampling rate to sample timebase and sample interval convert scan rate to scan timebase and scan interval DAQ_Rate Select channels and their gains y and scan rate divisors SCAN_Sequence_Setup y Allocate your buffer using the values returned by SCAN_Sequence_Setup in the scansPerSequence and samplesPerSequence output variables Retrieve the scan sequence vector SCAN_Sequence_Retrieve Initiate multiple channel data acquisition y SCAN_Start gt Check ongoing data acquisition status y DAQ_Check Data acquisition complete Yes Rearrange the data in your data acquisition buffer so that all data from each channel is stored v in adjacent elements of your buffer SCAN_Sequence_Demux Add AMUX 64T y configuration for use in the
170. 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 G 2 ni com analog trigger API ARB asynchronous background acquisition bandwidth base address BCD BIOS bipolar bit block mode bus National Instruments Corporation G 3 Glossary 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 hardware a property of an event that occurs at an arbitrary time without synchronization to a reference clock 2
171. 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_VScal1e function to obtain the voltage read at the module input In many of the data acquisition function descriptions in the Traditional NI DAQ C Reference Help 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 The SCXI 1100 SCXI 1101 SCXI 1102 B C SCXI 1104 C SCXI 1112
172. tines convert voltages read from a strain gage into measured strain using the appropriate formula for the strain gage 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 Traditional NI DAQ installs 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 The conversion routines are included in Traditional NI DAQ as source files rather than driver function calls so that you have complete access to the National Instruments Corporation 5 1 Traditional NI DAQ User Manual Chapter 5 Transducer Conversion Functions 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 ap
173. tings 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 MAX ni com SCXI_ModuleID_Read SCXI_MuxCtr_Setup SCXI_Reset SCXI_Scale SCXI_SCAN_Setup SCXI_Set_Config National Instruments Corporation 3 87 Chapter 3 Software Overview 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 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 Traditional NI DAQ has downloaded to Slot 0 of the SCXI chassis Resets the specified module to its default state You also can 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 operation that the assigned DAQ device will perform The function downlo
174. tions used in manual ix counter usage in waveform generation 3 51 counter timer application tips See also counter timer functions counter timer operation event counting 3 74 general purpose counter timer functions 3 76 counter timer functions See also counter timer application tips counter timer operation general purpose counter timer functions application tips 3 76 GPCTR_Change_Parameter 3 76 4 10 GPCTR_Config_Buffer 3 76 GPCTR_Control 3 76 GPCTR_Read_Buffer 3 76 4 11 4 12 GPCTR_Set_Application 3 76 GPCTR_Watch 3 76 counter timer operation clocks or time counters clock synchronization 3 78 IRIG B 3 79 PPS 3 79 sample use cases 3 78 data acquisition function application tips 3 25 customer education A 1 professional services A 1 technical support A 1 National Instruments Corporation l 3 Index D DAQ system setting up 1 2 DAQ Check function 3 22 DAQ Clear function 3 22 DAQ Config function 3 22 DAQ_DB_Config function 3 24 4 10 DAQ_DB_HalfReady function 3 24 4 11 DAQ_DB _ Transfer function 3 24 4 11 DAQ Monitor function 3 22 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 21 DAQ_VScale function 3 23 data acquisition application tips basic building blocks 3 25 building block 1 configuration functions 3 26 building block 2 start functions 3 26 building block 3 ch
175. to a DIG_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 nye 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 Pattern Generation 1 0 with 653X PCI 6115 PCI 6120 and 673X Devices Traditional NI DAQ User Manual Use pattern generation 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 3 72 ni com Chapter 3 Software Overview DIG_Block_In or DIG_Block_Out call automatically uses this mode Each group for the 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 I O connector For an input group pattern generation is analogous to a data acquisition operation but instead of reading analog input channels Traditional NI DAQ reads the digital ports For an output group pattern generation
176. tput port or has latched data into an input port The handshaking mode for the PCI 6115 PCI 6120 and 673X devices 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 PCI 6115 PCI 6120 and 673X 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 handshaking mode DIO 24 6025E AT MIO 16DE 10 and DIO 96 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 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 Refer to Digital I O Application Tips section and the DIG_SCAN_Setup function description of the Traditional NI DAQ C Reference Help for more details 653X Device Groups On the 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 1 and
177. ts 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 refer to your SCXI user manual The filter setting on the SCXI 1100 and the SCXI 1122 dramatically affects settling time Refer to the Specifications appendix in your SCXI module user manual for details National Instruments Corporation 3 101 Traditional NI DAQ User Manual Chapter 3 Software Overview B 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 34 instead of the channel scanning method shown in Figure 3 35 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 Traditional NI DAQ functions is simple Call the SCXI_AO_Write function to write the voltages you want to the module DAC
178. tup Initializes the device for a multirate scanned data acquisition operation Initialization includes selecting the channels to be scanned assigning gains to Traditional NI DAQ User Manual Chapter 3 Software Overview 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 Traditional NI DAQ C Reference Help to determine which functions your device supports DAQ_DB_ Config Enables or disables double buffered data acquisition operations 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 the function This function waits until the data to be transferred is available before returning You can execute DAQ_DB_Transfer repeatedly to return
179. u call the function again to change it You also can 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 32 shows the function call sequence of a single channel or software scanning application using a Simultaneous Sample and Hold SSH module in multiplexed mode 3 92 ni com 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 on a 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 AT functions Single Analog Input m SCXI_Change_Chan SCXI_Change_Chan a A A If desired change the Do you wish If desired change the selected channel on to take more selected channel on the module data while the the module module is in Hold mode M
180. u have placed on your form To do so add the following code in the Command1_Click subroutine as follows Redim buffer 10000 GeneralDAQEvent1 ChanStr AIO GeneralDAQEvent1 Refresh refresh to set params er DAQ Start 1 0 1 buffer 0 10000 3 10 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 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 3 14 ni com Chapter 3 Software Overview Text1 Text Str Scans amp scans have been acquired Else Text1 Text Acquisition is complete er 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 the Click Me button the text box should update its contents every second After all the scans are ac
181. uffered 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 refer to Chapter 4 Traditional NI DAQ Double Buffering National Instruments Corporation 3 31 Traditional NI DAQ User Manual Chapter 3 Software Overview Traditional NI DAQ User Manual 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 buffer size to a minimum 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 and 12 3 32 ni com Chap
182. ule with the SCXI 1321 terminal Traditional NI DAQ User Manual Chapter 3 Software Overview SCXI_Change_Chan SCXI_Configure_Connection SCXI_Configure_Filter SCXI_Get_Chassis_Info SCXI_Get_Module_Info SCXI_Get_State SCXI_Get_Status SCXI_Load_Config Traditional NI DAQ User Manual 3 86 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 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 set
183. ur E Series 671X or 673X device and to select a set of calibration constants for Traditional NI DAQ to use Configure_HW_Analog_Trigger LPM16_Calibrate MIO_Config SCXI_Calibrate Select_Signal 3 4 Configures the hardware analog trigger available on your E Series device 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 each and adjusts zero error to less than 1 LSB Turns dithering on and off For the MIO 64 this function also lets you specify whether to use AMUX 64T channels or onboard channels Performs a self calibration or internal calibration for certain SCXI modules 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 com Chapter 3 Software Overview Event Message Functions Traditional 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 Event Message dispatcher notifies 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
184. ut 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 if partial transfers of half buffers are enabled Counter Timer Function Group The Counter Timer function group contains the General Purpose Counter Timer GPCTR functions These 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 Refer to your hardware user manual to find out which operations are supported by your device Counter Timer Operation for the GPCTR Functions Figure 3 26 shows the 16 bit counters available on DSA devices supported by GPCTR functions SOURCE Counter OUT GATE Figure 3 26 16 bit Counter Block Diagram Traditional NI DAQ User Manual 3 74 ni com Chapter 3 Software Overview Each counter has a SOURCE input a GATE input and an output labeled OUT 24 bit and 32 bit counters also have an AUX UP_DOWN input as shown in Figure 3 27 SOURCE GATE Counter OUT AUX UP_DOWN Figure 3 27 24 bit and 32 bit Counter Block Diagram When using a 24 bit or 32 bit counter for event counting the input signals perform the following functions e
185. utput 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 Nulls the offset in the specified strain gage on an SCXI 1520 strain gage module by adjusting the internal potentiometers ni com Chapter 3 Software Overview SCXI_Track_Hold_Control Controls the track and hold modules track hold state that you set up for a single channel operation SCXI_Track_Hold_Setup 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 SCXI Application Tips There are three categories of SCXI applications analog input applications analog output applications and digital applications Figure 3 30 shows the basic structure of an SCXI application Load SCXI configuration that was entered in the MAX and initialize software defaults SCXI_Load_Config Reset the chassis and modules to their default hardware settings SCXI_Reset ai y Vv Vv Analog Input Operations Analog Output Operations Digital Operations Yy Yes Reset the chassis and modules to their default hardware settings SCXI_Reset Figure 3 30 General SCXIbus Application The figur
186. view e Lab_ISCAN_Op LPM devices only DAQ_to_Disk e SCAN_to_Disk MIO AI and DSA devices only e Lab _ISCAN_to_Disk LPM 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 Streaming to disk Scan Multiple Channels Scan Multiple Channels MIO Al or Yes DSA Device MIO Al or DSA Device 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 Traditional 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 Traditional NI DAQ User Manual Chapter 3 Software 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 Convert sampling rat
187. w Select Counter Application Program Counter Arm Read Attributes or Buffer Configure Buffer if needed Change Counter Attributes Reset Counter Figure 3 28 Generic Program Flow for All GPCTR 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 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
188. wed Property Values Name GeneralDAQEventn default Board 1 n default ChanStr Refer to Config_DAQ_Event_Message in the Traditional NI DAQ C Reference Help Level Single voltage WindowSize Single voltage Slope 0 Positive default 1 Negative TrigSkipCount Long PreTrigScans Long PostTrigScans Long National Instruments Corporation 3 9 Traditional NI DAQ User Manual Chapter 3 Software Overview Table 3 2 Analog Trigger Event Control Properties Continued Property Allowed Property Values Index N A Tag N A Enabled O0 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 Traditional NI DAQ C Reference Help 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 Traditional NI DAQ functions 2 Set the Enabled property of the Analog Trigger Event control to 1 True 3 Invoke the AnalogTrigger
189. ynchronizes the module scan list with the DAQ device scan list In most cases especially when using interval scanning it is best to ensure that the number of samples Traditional NI DAQ takes in one pass through the module scan list is the same as the number of samples Traditional NI DAQ takes in one pass through the DAQ device scan list Refer to the SCXI_MuxCtr_Setup function description in the Traditional NI DAQ C Reference Help 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 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 34 to set up the modules for analog input operations After you have initialized and reset the SCXI chassis and modules you can use the 3 96 ni com Chapter 3 Software Overview 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

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