用户手册目录NI USB-621x User Manual1Support2Worldwide Technical Support and Product Information2National Instruments Corporate Headquarters2Worldwide Offices2Important Information3Warranty3Copyright3Trademarks3Patents3WARNING REGARDING USE OF NATIONAL INSTRUMENTS PRODUCTS3Contents5About This Manual13Conventions13Related Documentation14NI-DAQmx for Windows14LabVIEW14LabWindows™/CVI™15Measurement Studio15ANSI C without NI Application Software15.NET Languages without NI Application Software16Device Documentation and Specifications16Training Courses16Technical Support on the Web16Chapter 1 Getting Started17Figure 1-1. USB-6210/621117Figure 1-2. USB-6215/621818Installing NI-DAQmx18Installing Other Software18Installing the Hardware19Device Pinouts19Device Specifications19Device Accessories19Chapter 2 DAQ System Overview20Figure 2-1. Components of a Typical DAQ System20DAQ Hardware20Figure 2-2. USB-621x Block Diagram21DAQ-STC221Calibration Circuitry21Signal Conditioning22Sensors and Transducers22Programming Devices in Software23Chapter 3 Connector Information24I/O Connector Signal Descriptions24Table 3-1. I/O Connector Signals24+5 V Power25+5 V Power as an Output25+5 V Power as an Input26Chapter 4 Analog Input27Figure 4-1. M Series Analog Input Circuitry27Analog Input Circuitry27Analog Input Range28Table 4-1. Input Ranges for NI 621x29Analog Input Ground-Reference Settings29Table 4-2. Analog Input Ground-Reference Settings29Figure 4-2. NI-PGIA30Table 4-3. Signals Routed to the NI-PGIA30Configuring AI Ground-Reference Settings in Software31Figure 4-3. Enabling Multimode Scanning in LabVIEW31Multichannel Scanning Considerations32Use Low Impedance Sources32Carefully Choose the Channel Scanning Order33Avoid Switching from a Large to a Small Input Range33Insert Grounded Channel between Signal Channels33Minimize Voltage Step between Adjacent Channels34Avoid Scanning Faster Than Necessary34Example 134Example 235Analog Input Data Acquisition Methods35Software-Timed Acquisitions35Hardware-Timed Acquisitions35Buffered36Non-Buffered36Analog Input Digital Triggering36Field Wiring Considerations37Analog Input Timing Signals37Figure 4-4. Analog Input Timing Options38Figure 4-5. Interval Sampling38Figure 4-6. Posttriggered Data Acquisition Example39Figure 4-7. Pretriggered Data Acquisition Example40AI Sample Clock Signal40Using an Internal Source41Using an External Source41Routing AI Sample Clock Signal to an Output Terminal41Other Timing Requirements41Figure 4-8. ai/SampleClock and ai/StartTrigger42AI Sample Clock Timebase Signal42AI Convert Clock Signal42Using an Internal Source43Using an External Source43Routing AI Convert Clock Signal to an Output Terminal43Using a Delay from Sample Clock to Convert Clock43Figure 4-9. ai/SampleClock and ai/ConvertClock44Other Timing Requirements44Figure 4-10. ai/SampleClock Too Fast45Figure 4-11. ai/ConvertClock Too Fast45Figure 4-12. ai/SampleClock and ai/ConvertClock Improperly Matched45Figure 4-13. ai/SampleClock and ai/ConvertClock Properly Matched46Figure 4-14. Single External Signal Driving ai/SampleClock and ai/ConvertClock Simultaneously46AI Convert Clock Timebase Signal46AI Hold Complete Event Signal47AI Start Trigger Signal47Using a Digital Source47Routing AI Start Trigger to an Output Terminal47AI Reference Trigger Signal48Figure 4-15. Reference Trigger Final Buffer48Using a Digital Source49Routing AI Reference Trigger Signal to an Output Terminal49AI Pause Trigger Signal49Using a Digital Source49Getting Started with AI Applications in Software50Chapter 5 Connecting AI Signals on the USB-6210/6211 Devices51Table 5-1. Analog Input Configuration52Connecting Floating Signal Sources53What Are Floating Signal Sources?53When to Use Differential Connections with Floating Signal Sources53When to Use Referenced Single-Ended (RSE) Connections with Floating Signal Sources53When to Use Non-Referenced Single-Ended (NRSE) Connections with Floating Signal Sources54Using Differential Connections for Floating Signal Sources55Figure 5-1. Differential Connections for Floating Signal Sources without Bias Resistors55Figure 5-2. Differential Connections for Floating Signal Sources with Single Bias Resistor56Figure 5-3. Differential Connections for Floating Signal Sources with Balanced Bias Resistors57Figure 5-4. Differential Connections for AC Coupled Floating Sources with Balanced Bias Resistors58Using Non-Referenced Single-Ended (NRSE) Connections for Floating Signal Sources58Figure 5-5. NRSE Connections for Floating Signal Sources58Using Referenced Single-Ended (RSE) Connections for Floating Signal Sources59Figure 5-6. RSE Connections for Floating Signal Sources59Connecting Ground-Referenced Signal Sources59What Are Ground-Referenced Signal Sources?59When to Use Differential Connections with Ground-Referenced Signal Sources60When to Use Non-Referenced Single-Ended (NRSE) Connections with Ground-Referenced Signal Sources60When to Use Referenced Single-Ended (RSE) Connections with Ground-Referenced Signal Sources61Using Differential Connections for Ground-Referenced Signal Sources62Figure 5-7. Differential Connections for Ground-Referenced Signal Sources62Using Non-Referenced Single-Ended (NRSE) Connections for Ground-Referenced Signal Sources63Figure 5-8. Single-Ended Connections for Ground-Referenced Signal Sources (NRSE Configuration)63Chapter 6 Connecting AI Signals on the USB-6215/6218 Devices64Differential Measurements64Differential Pairs64Table 6-1. I/O Connector Signals64Figure 6-1. Connecting a Device to a USB-6215/6218 Using Differential Connections65Referenced Single-Ended (RSE) Measurements66Figure 6-2. Connecting a Device to a USB-6215/6218 Using RSE Connections66Non-Referenced Single-Ended (NRSE) Measurements67Figure 6-3. Connecting a Device to a USB-6215/6218 Using NRSE Connections67Chapter 7 Analog Output68Figure 7-1. M Series Analog Output Circuitry68Analog Output Circuitry68AO Range69Minimizing Glitches on the Output Signal69Analog Output Data Generation Methods69Software-Timed Generations69Hardware-Timed Generations69Analog Output Digital Triggering71Connecting Analog Output Signals71Figure 7-2. Analog Output Connections71Analog Output Timing Signals72Figure 7-3. Analog Output Timing Options72AO Start Trigger Signal72Using a Digital Source72Routing AO Start Trigger Signal to an Output Terminal73AO Pause Trigger Signal73Figure 7-4. ao/PauseTrigger with Other Signal Source73Using a Digital Source73AO Sample Clock Signal74Using an Internal Source74Using an External Source74Routing AO Sample Clock Signal to an Output Terminal74Other Timing Requirements74Figure 7-5. ao/SampleClock and ao/StartTrigger75AO Sample Clock Timebase Signal75Getting Started with AO Applications in Software76Chapter 8 Digital I/O77Figure 8-1. M Series Digital I/O Circuitry77Static DIO78I/O Protection78Increasing Current Drive78Connecting Digital I/O Signals79Figure 8-2. Digital I/O Connections79Getting Started with DIO Applications in Software80Chapter 9 Counters81Figure 9-1. M Series Counters81Counter Input Applications82Counting Edges82Single Point (On-Demand) Edge Counting82Figure 9-2. Single Point (On-Demand) Edge Counting82Figure 9-3. Single Point (On-Demand) Edge Counting with Pause Trigger83Buffered (Sample Clock) Edge Counting83Figure 9-4. Buffered (Sample Clock) Edge Counting83Non-Cumulative Buffered Edge Counting84Figure 9-5. Non-Cumulative Buffered Edge Counting84Controlling the Direction of Counting84Pulse-Width Measurement85Single Pulse-Width Measurement85Figure 9-6. Single Pulse-Width Measurement85Buffered Pulse-Width Measurement85Figure 9-7. Buffered Pulse-Width Measurement86Period Measurement86Single Period Measurement87Figure 9-8. Single Period Measurement87Buffered Period Measurement87Figure 9-9. Buffered Period Measurement88Table 9-1. Time N Descriptions88Semi-Period Measurement89Single Semi-Period Measurement89Buffered Semi-Period Measurement89Figure 9-10. Buffered Semi-Period Measurement89Frequency Measurement90Method 1-Measure Low Frequency with One Counter90Figure 9-11. Method 190Method 1b-Measure Low Frequency with One Counter (Averaged)91Figure 9-12. Method 1b91Method 2-Measure High Frequency with Two Counters91Figure 9-13. Method 292Method 3-Measure Large Range of Frequencies Using Two Counters92Figure 9-14. Method 393Choosing a Method for Measuring Frequency93Table 9-2. Frequency Measurement Method 194Table 9-3. Frequency Measurement Method Comparison95Position Measurement95Measurements Using Quadrature Encoders95Figure 9-15. X1 Encoding96Figure 9-16. X2 Encoding96Figure 9-17. X4 Encoding96Figure 9-18. Channel Z Reload with X4 Decoding97Measurements Using Two Pulse Encoders97Figure 9-19. Measurements Using Two Pulse Encoders98Two-Signal Edge-Separation Measurement98Single Two-Signal Edge-Separation Measurement98Figure 9-20. Single Two-Signal Edge-Separation Measurement99Buffered Two-Signal Edge-Separation Measurement99Figure 9-21. Buffered Two-Signal Edge-Separation Measurement99Counter Output Applications100Simple Pulse Generation100Single Pulse Generation100Figure 9-22. Single Pulse Generation100Single Pulse Generation with Start Trigger100Figure 9-23. Single Pulse Generation with Start Trigger101Retriggerable Single Pulse Generation101Figure 9-24. Retriggerable Single Pulse Generation101Pulse Train Generation102Continuous Pulse Train Generation102Figure 9-25. Continuous Pulse Train Generation102Frequency Generation103Using the Frequency Generator103Figure 9-26. Frequency Generator Block Diagram103Figure 9-27. Frequency Generator Output Waveform103Frequency Division104Pulse Generation for ETS104Figure 9-28. Pulse Generation for ETS105Counter Timing Signals105Counter n Source Signal106Table 9-4. Counter Applications and Counter n Source106Routing a Signal to Counter n Source106Routing Counter n Source to an Output Terminal106Counter n Gate Signal107Routing a Signal to Counter n Gate107Routing Counter n Gate to an Output Terminal107Counter n Aux Signal107Routing a Signal to Counter n Aux107Counter n A, Counter n B, and Counter n Z Signals108Routing Signals to A, B, and Z Counter Inputs108Counter n Up_Down Signal108Counter n HW Arm Signal108Routing Signals to Counter n HW Arm Input108Counter n Internal Output and Counter n TC Signals109Routing Counter n Internal Output to an Output Terminal109Frequency Output Signal109Routing Frequency Output to a Terminal109Default Counter/Timer Pinouts109Table 9-5. Default NI-DAQmx Counter/Timer Pins for USB-6210/6211/6215 Devices109Table 9-6. Default NI-DAQmx Counter/Timer Pins for USB-6218 Devices110Counter Triggering111Arm Start Trigger111Start Trigger111Pause Trigger111Other Counter Features112Sample Clock112Figure 9-29. Sample Clock Example112Table 9-7. Time N Descriptions113Cascading Counters113Counter Filters113Table 9-8. Filters114Figure 9-30. Filter Example114Prescaling114Figure 9-31. Prescaling115Duplicate Count Prevention115Example Application That Works Correctly (No Duplicate Counting)116Figure 9-32. Duplicate Count Prevention Example116Example Application That Works Incorrectly (Duplicate Counting)117Figure 9-33. Duplicate Count Example117Example Application That Prevents Duplicate Count117Figure 9-34. Duplicate Count Prevention Example117Enabling Duplicate Count Prevention in NI-DAQmx118Chapter 10 PFI119Figure 10-1. NI 621x PFI Input Circuitry119Figure 10-2. NI 621x PFI Output Circuitry120Using PFI Terminals as Timing Input Signals120Exporting Timing Output Signals Using PFI Terminals121Using PFI Terminals as Static Digital I/Os121Connecting PFI Input Signals121Figure 10-3. PFI Input Signals Connections122PFI Filters122Table 10-1. Filters123Figure 10-4. Filter Example123I/O Protection124Programmable Power-Up States124Chapter 11 Isolation and Digital Isolators125Table 11-1. Ground Symbols125Figure 11-1. General NI 621x Block Diagram125Digital Isolation126Benefits of an Isolated DAQ Device126Reducing Common-Mode Noise126Creating an AC Return Path127Isolated Systems127Non-Isolated Systems127Chapter 12 Digital Routing and Clock Generation12980 MHz Timebase12920 MHz Timebase129100 kHz Timebase130Chapter 13 Bus Interface131USB Signal Streams131Data Transfer Methods131USB Signal Stream131Programmed I/O132Changing Data Transfer Methods132Chapter 14 Triggering133Triggering with a Digital Source133Figure 14-1. Falling-Edge Trigger133Appendix A Device-Specific Information135Figure A-1. USB-6210 Pinout136Table A-1. Default NI-DAQmx Counter/Timer Pins136Table A-2. PWR/ACT LED Status137Figure A-2. USB-6211/6215 Pinout139Table A-3. Default NI-DAQmx Counter/Timer Pins139Table A-4. PWR/ACT LED Status140Figure A-3. USB 6218 Pinout142Table A-5. Default NI-DAQmx Counter/Timer Pins142Table A-6. PWR/ACT LED Status143Appendix B Troubleshooting145Figure B-1. ai/SampleClock and ai/ConvertClock146Appendix C Technical Support and Professional Services148Glossary150A150B-C152D154E156F157G-I158K159L-M160N161O-P162Q-S164T166U-V167W168Index169Symbols169Numerics169A169B-C170D171E172F-I173K-N174O-R175S176T-U177W-X178Device Pinouts136Figure A-1. USB-6210 Pinout136Figure A-2. USB-6211/6215 Pinout139Figure A-3. USB 6218 Pinout142文件大小: 4.0 MB页数: 178Language: English打开用户手册
用户手册目录NI USB-621x User Manual1Support2Worldwide Technical Support and Product Information2National Instruments Corporate Headquarters2Worldwide Offices2Important Information3Warranty3Copyright3Trademarks3Patents3WARNING REGARDING USE OF NATIONAL INSTRUMENTS PRODUCTS3Contents5About This Manual13Conventions13Related Documentation14NI-DAQmx for Windows14LabVIEW14LabWindows™/CVI™15Measurement Studio15ANSI C without NI Application Software15.NET Languages without NI Application Software16Device Documentation and Specifications16Training Courses16Technical Support on the Web16Chapter 1 Getting Started17Figure 1-1. USB-6210/621117Figure 1-2. USB-6215/621818Installing NI-DAQmx18Installing Other Software18Installing the Hardware19Device Pinouts19Device Specifications19Device Accessories19Chapter 2 DAQ System Overview20Figure 2-1. Components of a Typical DAQ System20DAQ Hardware20Figure 2-2. USB-621x Block Diagram21DAQ-STC221Calibration Circuitry21Signal Conditioning22Sensors and Transducers22Programming Devices in Software23Chapter 3 Connector Information24I/O Connector Signal Descriptions24Table 3-1. I/O Connector Signals24+5 V Power25+5 V Power as an Output25+5 V Power as an Input26Chapter 4 Analog Input27Figure 4-1. M Series Analog Input Circuitry27Analog Input Circuitry27Analog Input Range28Table 4-1. Input Ranges for NI 621x29Analog Input Ground-Reference Settings29Table 4-2. Analog Input Ground-Reference Settings29Figure 4-2. NI-PGIA30Table 4-3. Signals Routed to the NI-PGIA30Configuring AI Ground-Reference Settings in Software31Figure 4-3. Enabling Multimode Scanning in LabVIEW31Multichannel Scanning Considerations32Use Low Impedance Sources32Carefully Choose the Channel Scanning Order33Avoid Switching from a Large to a Small Input Range33Insert Grounded Channel between Signal Channels33Minimize Voltage Step between Adjacent Channels34Avoid Scanning Faster Than Necessary34Example 134Example 235Analog Input Data Acquisition Methods35Software-Timed Acquisitions35Hardware-Timed Acquisitions35Buffered36Non-Buffered36Analog Input Digital Triggering36Field Wiring Considerations37Analog Input Timing Signals37Figure 4-4. Analog Input Timing Options38Figure 4-5. Interval Sampling38Figure 4-6. Posttriggered Data Acquisition Example39Figure 4-7. Pretriggered Data Acquisition Example40AI Sample Clock Signal40Using an Internal Source41Using an External Source41Routing AI Sample Clock Signal to an Output Terminal41Other Timing Requirements41Figure 4-8. ai/SampleClock and ai/StartTrigger42AI Sample Clock Timebase Signal42AI Convert Clock Signal42Using an Internal Source43Using an External Source43Routing AI Convert Clock Signal to an Output Terminal43Using a Delay from Sample Clock to Convert Clock43Figure 4-9. ai/SampleClock and ai/ConvertClock44Other Timing Requirements44Figure 4-10. ai/SampleClock Too Fast45Figure 4-11. ai/ConvertClock Too Fast45Figure 4-12. ai/SampleClock and ai/ConvertClock Improperly Matched45Figure 4-13. ai/SampleClock and ai/ConvertClock Properly Matched46Figure 4-14. Single External Signal Driving ai/SampleClock and ai/ConvertClock Simultaneously46AI Convert Clock Timebase Signal46AI Hold Complete Event Signal47AI Start Trigger Signal47Using a Digital Source47Routing AI Start Trigger to an Output Terminal47AI Reference Trigger Signal48Figure 4-15. Reference Trigger Final Buffer48Using a Digital Source49Routing AI Reference Trigger Signal to an Output Terminal49AI Pause Trigger Signal49Using a Digital Source49Getting Started with AI Applications in Software50Chapter 5 Connecting AI Signals on the USB-6210/6211 Devices51Table 5-1. Analog Input Configuration52Connecting Floating Signal Sources53What Are Floating Signal Sources?53When to Use Differential Connections with Floating Signal Sources53When to Use Referenced Single-Ended (RSE) Connections with Floating Signal Sources53When to Use Non-Referenced Single-Ended (NRSE) Connections with Floating Signal Sources54Using Differential Connections for Floating Signal Sources55Figure 5-1. Differential Connections for Floating Signal Sources without Bias Resistors55Figure 5-2. Differential Connections for Floating Signal Sources with Single Bias Resistor56Figure 5-3. Differential Connections for Floating Signal Sources with Balanced Bias Resistors57Figure 5-4. Differential Connections for AC Coupled Floating Sources with Balanced Bias Resistors58Using Non-Referenced Single-Ended (NRSE) Connections for Floating Signal Sources58Figure 5-5. NRSE Connections for Floating Signal Sources58Using Referenced Single-Ended (RSE) Connections for Floating Signal Sources59Figure 5-6. RSE Connections for Floating Signal Sources59Connecting Ground-Referenced Signal Sources59What Are Ground-Referenced Signal Sources?59When to Use Differential Connections with Ground-Referenced Signal Sources60When to Use Non-Referenced Single-Ended (NRSE) Connections with Ground-Referenced Signal Sources60When to Use Referenced Single-Ended (RSE) Connections with Ground-Referenced Signal Sources61Using Differential Connections for Ground-Referenced Signal Sources62Figure 5-7. Differential Connections for Ground-Referenced Signal Sources62Using Non-Referenced Single-Ended (NRSE) Connections for Ground-Referenced Signal Sources63Figure 5-8. Single-Ended Connections for Ground-Referenced Signal Sources (NRSE Configuration)63Chapter 6 Connecting AI Signals on the USB-6215/6218 Devices64Differential Measurements64Differential Pairs64Table 6-1. I/O Connector Signals64Figure 6-1. Connecting a Device to a USB-6215/6218 Using Differential Connections65Referenced Single-Ended (RSE) Measurements66Figure 6-2. Connecting a Device to a USB-6215/6218 Using RSE Connections66Non-Referenced Single-Ended (NRSE) Measurements67Figure 6-3. Connecting a Device to a USB-6215/6218 Using NRSE Connections67Chapter 7 Analog Output68Figure 7-1. M Series Analog Output Circuitry68Analog Output Circuitry68AO Range69Minimizing Glitches on the Output Signal69Analog Output Data Generation Methods69Software-Timed Generations69Hardware-Timed Generations69Analog Output Digital Triggering71Connecting Analog Output Signals71Figure 7-2. Analog Output Connections71Analog Output Timing Signals72Figure 7-3. Analog Output Timing Options72AO Start Trigger Signal72Using a Digital Source72Routing AO Start Trigger Signal to an Output Terminal73AO Pause Trigger Signal73Figure 7-4. ao/PauseTrigger with Other Signal Source73Using a Digital Source73AO Sample Clock Signal74Using an Internal Source74Using an External Source74Routing AO Sample Clock Signal to an Output Terminal74Other Timing Requirements74Figure 7-5. ao/SampleClock and ao/StartTrigger75AO Sample Clock Timebase Signal75Getting Started with AO Applications in Software76Chapter 8 Digital I/O77Figure 8-1. M Series Digital I/O Circuitry77Static DIO78I/O Protection78Increasing Current Drive78Connecting Digital I/O Signals79Figure 8-2. Digital I/O Connections79Getting Started with DIO Applications in Software80Chapter 9 Counters81Figure 9-1. M Series Counters81Counter Input Applications82Counting Edges82Single Point (On-Demand) Edge Counting82Figure 9-2. Single Point (On-Demand) Edge Counting82Figure 9-3. Single Point (On-Demand) Edge Counting with Pause Trigger83Buffered (Sample Clock) Edge Counting83Figure 9-4. Buffered (Sample Clock) Edge Counting83Non-Cumulative Buffered Edge Counting84Figure 9-5. Non-Cumulative Buffered Edge Counting84Controlling the Direction of Counting84Pulse-Width Measurement85Single Pulse-Width Measurement85Figure 9-6. Single Pulse-Width Measurement85Buffered Pulse-Width Measurement85Figure 9-7. Buffered Pulse-Width Measurement86Period Measurement86Single Period Measurement87Figure 9-8. Single Period Measurement87Buffered Period Measurement87Figure 9-9. Buffered Period Measurement88Table 9-1. Time N Descriptions88Semi-Period Measurement89Single Semi-Period Measurement89Buffered Semi-Period Measurement89Figure 9-10. Buffered Semi-Period Measurement89Frequency Measurement90Method 1-Measure Low Frequency with One Counter90Figure 9-11. Method 190Method 1b-Measure Low Frequency with One Counter (Averaged)91Figure 9-12. Method 1b91Method 2-Measure High Frequency with Two Counters91Figure 9-13. Method 292Method 3-Measure Large Range of Frequencies Using Two Counters92Figure 9-14. Method 393Choosing a Method for Measuring Frequency93Table 9-2. Frequency Measurement Method 194Table 9-3. Frequency Measurement Method Comparison95Position Measurement95Measurements Using Quadrature Encoders95Figure 9-15. X1 Encoding96Figure 9-16. X2 Encoding96Figure 9-17. X4 Encoding96Figure 9-18. Channel Z Reload with X4 Decoding97Measurements Using Two Pulse Encoders97Figure 9-19. Measurements Using Two Pulse Encoders98Two-Signal Edge-Separation Measurement98Single Two-Signal Edge-Separation Measurement98Figure 9-20. Single Two-Signal Edge-Separation Measurement99Buffered Two-Signal Edge-Separation Measurement99Figure 9-21. Buffered Two-Signal Edge-Separation Measurement99Counter Output Applications100Simple Pulse Generation100Single Pulse Generation100Figure 9-22. Single Pulse Generation100Single Pulse Generation with Start Trigger100Figure 9-23. Single Pulse Generation with Start Trigger101Retriggerable Single Pulse Generation101Figure 9-24. Retriggerable Single Pulse Generation101Pulse Train Generation102Continuous Pulse Train Generation102Figure 9-25. Continuous Pulse Train Generation102Frequency Generation103Using the Frequency Generator103Figure 9-26. Frequency Generator Block Diagram103Figure 9-27. Frequency Generator Output Waveform103Frequency Division104Pulse Generation for ETS104Figure 9-28. Pulse Generation for ETS105Counter Timing Signals105Counter n Source Signal106Table 9-4. Counter Applications and Counter n Source106Routing a Signal to Counter n Source106Routing Counter n Source to an Output Terminal106Counter n Gate Signal107Routing a Signal to Counter n Gate107Routing Counter n Gate to an Output Terminal107Counter n Aux Signal107Routing a Signal to Counter n Aux107Counter n A, Counter n B, and Counter n Z Signals108Routing Signals to A, B, and Z Counter Inputs108Counter n Up_Down Signal108Counter n HW Arm Signal108Routing Signals to Counter n HW Arm Input108Counter n Internal Output and Counter n TC Signals109Routing Counter n Internal Output to an Output Terminal109Frequency Output Signal109Routing Frequency Output to a Terminal109Default Counter/Timer Pinouts109Table 9-5. Default NI-DAQmx Counter/Timer Pins for USB-6210/6211/6215 Devices109Table 9-6. Default NI-DAQmx Counter/Timer Pins for USB-6218 Devices110Counter Triggering111Arm Start Trigger111Start Trigger111Pause Trigger111Other Counter Features112Sample Clock112Figure 9-29. Sample Clock Example112Table 9-7. Time N Descriptions113Cascading Counters113Counter Filters113Table 9-8. Filters114Figure 9-30. Filter Example114Prescaling114Figure 9-31. Prescaling115Duplicate Count Prevention115Example Application That Works Correctly (No Duplicate Counting)116Figure 9-32. Duplicate Count Prevention Example116Example Application That Works Incorrectly (Duplicate Counting)117Figure 9-33. Duplicate Count Example117Example Application That Prevents Duplicate Count117Figure 9-34. Duplicate Count Prevention Example117Enabling Duplicate Count Prevention in NI-DAQmx118Chapter 10 PFI119Figure 10-1. NI 621x PFI Input Circuitry119Figure 10-2. NI 621x PFI Output Circuitry120Using PFI Terminals as Timing Input Signals120Exporting Timing Output Signals Using PFI Terminals121Using PFI Terminals as Static Digital I/Os121Connecting PFI Input Signals121Figure 10-3. PFI Input Signals Connections122PFI Filters122Table 10-1. Filters123Figure 10-4. Filter Example123I/O Protection124Programmable Power-Up States124Chapter 11 Isolation and Digital Isolators125Table 11-1. Ground Symbols125Figure 11-1. General NI 621x Block Diagram125Digital Isolation126Benefits of an Isolated DAQ Device126Reducing Common-Mode Noise126Creating an AC Return Path127Isolated Systems127Non-Isolated Systems127Chapter 12 Digital Routing and Clock Generation12980 MHz Timebase12920 MHz Timebase129100 kHz Timebase130Chapter 13 Bus Interface131USB Signal Streams131Data Transfer Methods131USB Signal Stream131Programmed I/O132Changing Data Transfer Methods132Chapter 14 Triggering133Triggering with a Digital Source133Figure 14-1. Falling-Edge Trigger133Appendix A Device-Specific Information135Figure A-1. USB-6210 Pinout136Table A-1. Default NI-DAQmx Counter/Timer Pins136Table A-2. PWR/ACT LED Status137Figure A-2. USB-6211/6215 Pinout139Table A-3. Default NI-DAQmx Counter/Timer Pins139Table A-4. PWR/ACT LED Status140Figure A-3. USB 6218 Pinout142Table A-5. Default NI-DAQmx Counter/Timer Pins142Table A-6. PWR/ACT LED Status143Appendix B Troubleshooting145Figure B-1. ai/SampleClock and ai/ConvertClock146Appendix C Technical Support and Professional Services148Glossary150A150B-C152D154E156F157G-I158K159L-M160N161O-P162Q-S164T166U-V167W168Index169Symbols169Numerics169A169B-C170D171E172F-I173K-N174O-R175S176T-U177W-X178Device Pinouts136Figure A-1. USB-6210 Pinout136Figure A-2. USB-6211/6215 Pinout139Figure A-3. USB 6218 Pinout142文件大小: 4.0 MB页数: 178Language: English打开用户手册