Document Outline

• NI USB-621x User Manual
• Support
  • Worldwide Technical Support and Product Information
  • National Instruments Corporate Headquarters
  • Worldwide Offices
• Important Information
  • Warranty
  • Copyright
  • Trademarks
  • Patents
  • WARNING REGARDING USE OF NATIONAL INSTRUMENTS PRODUCTS
• Compliance
• Contents
• About This Manual
  • Conventions
  • Related Documentation
    • NI-DAQmx for Windows
    • NI-DAQmx Base (Linux/Mac OS X/LabVIEW PDA 8.x)
    • LabVIEW
    • LabWindows/CVI
    • Measurement Studio
    • ANSI C without NI Application Software
    • .NET Languages without NI Application Software
    • Device Documentation and Specifications
    • Training Courses
    • Technical Support on the Web
• Chapter 1 Getting Started
  • Installing NI-DAQmx
  • Installing Other Software
  • Installing the Hardware
  • Device Pinouts
  • Device Specifications
  • Applying Signal Labels to the USB-621x
    • Figure 1-1. USB-621x Signal Labels
  • USB Cable Strain Relief
    • Figure 1-2. USB Cable Strain Relief Options
  • Mounting the USB-621x
    • Desktop Use
      • Figure 1-3. Applying Rubber Feet to the USB-621x
    • DIN Rail Mounting
    • Panel Mounting
      • Figure 1-4. Mounting the USB-621x on a Panel
• Chapter 2 DAQ System Overview
  • Figure 2-1. Components of a Typical DAQ System
  • DAQ Hardware
    • Figure 2-2. USB-621x Block Diagram
    • DAQ-STC2
    • Calibration Circuitry
  • Signal Conditioning
    • Sensors and Transducers
  • Cables and Accessories
    • USB-621x Mass Termination Custom Cabling
  • Programming Devices in Software
• Chapter 3 Connector and LED Information
  • I/O Connector Signal Descriptions
    • Table 3-1. I/O Connector Signals
  • +5 V Power
    • +5 V Power as an Output
    • +5 V Power as an Input
  • USB Device Fuse Replacement
    • Figure 3-1. USB-621x Mass Termination Fuse Location
  • PWR/ACT LED Indicator
    • Table 3-2. PWR/ACT LED Status
• Chapter 4 Analog Input
  • Figure 4-1. USB-621x Analog Input Circuitry
  • Analog Input Range
  • Analog Input Ground-Reference Settings
    • Figure 4-2. NI-PGIA
    • Table 4-1. Signals Routed to the NI-PGIA
    • Configuring AI Ground-Reference Settings in Software
      • Figure 4-3. Enabling Multimode Scanning in LabVIEW
  • Multichannel Scanning Considerations
  • Analog Input Data Acquisition Methods
  • Analog Input Digital Triggering
  • Field Wiring Considerations
  • Analog Input Timing Signals
    • Figure 4-4. Analog Input Timing Options
    • Figure 4-5. Interval Sampling
    • Figure 4-6. Posttriggered Data Acquisition Example
    • Figure 4-7. Pretriggered Data Acquisition Example
    • AI Sample Clock Signal
      • Using an Internal Source
      • Using an External Source
      • Routing AI Sample Clock to an Output Terminal
      • Other Timing Requirements
      • Figure 4-8. AI Sample Clock and AI Start Trigger
    • AI Sample Clock Timebase Signal
    • AI Convert Clock Signal
      • Using an Internal Source
      • Using an External Source
      • Routing AI Convert Clock to an Output Terminal
      • Using a Delay from Sample Clock to Convert Clock
      • Figure 4-9. AI Sample Clock and AI Convert Clock
      • Other Timing Requirements
      • Figure 4-10. AI Sample Clock Too Fast For AI Convert Clock; AI Sample Clock Pulses Are Gated Off
      • Figure 4-11. AI Convert Clock Too Fast For AI Sample Clock; AI Convert Clock Pulses Are Gated Off
      • Figure 4-12. AI Sample Clock and AI Convert Clock Improperly Matched; Leads To Aperiodic Sampling
      • Figure 4-13. AI Sample Clock and AI Convert Clock Properly Matched
      • Figure 4-14. Single External Signal Driving AI Sample Clock and AI Convert Clock Simultaneously
    • AI Convert Clock Timebase Signal
    • AI Hold Complete Event Signal
    • AI Start Trigger Signal
      • Using a Digital Source
      • Routing AI Start Trigger to an Output Terminal
    • AI Reference Trigger Signal
      • Figure 4-15. Reference Trigger Final Buffer
      • Using a Digital Source
      • Routing AI Reference Trigger to an Output Terminal
    • AI Pause Trigger Signal
      • Using a Digital Source
  • Getting Started with AI Applications in Software
  • Connecting Analog Input Signals on USB-6210/6211/6212 Devices
    • Table 4-2. USB-6210/6211/6212 Analog Input Configuration
    • Connecting Floating Signal Sources
      • What Are Floating Signal Sources?
      • When to Use Differential Connections with Floating Signal Sources
      • When to Use Referenced Single-Ended (RSE) Connections with Floating Signal Sources
      • When to Use Non-Referenced Single-Ended (NRSE) Connections with Floating Signal Sources
      • Using Differential Connections for Floating Signal Sources
      • Figure 4-16. Differential Connections for Floating Signal Sources without Bias Resistors
      • Figure 4-17. Differential Connections for Floating Signal Sources with Single Bias Resistor
      • Figure 4-18. Differential Connections for Floating Signal Sources with Balanced Bias Resistors
      • Figure 4-19. Differential Connections for AC Coupled Floating Sources with Balanced Bias Resistors
      • Using Non-Referenced Single-Ended (NRSE) Connections for Floating Signal Sources
      • Figure 4-20. NRSE Connections for Floating Signal Sources
      • Using Referenced Single-Ended (RSE) Connections for Floating Signal Sources
      • Figure 4-21. RSE Connections for Floating Signal Sources
    • Connecting Ground-Referenced Signal Sources
      • What Are Ground-Referenced Signal Sources?
      • When to Use Differential Connections with Ground-Referenced Signal Sources
      • When to Use Non-Referenced Single-Ended (NRSE) Connections with Ground-Referenced Signal Sources
      • When to Use Referenced Single-Ended (RSE) Connections with Ground-Referenced Signal Sources
      • Using Differential Connections for Ground-Referenced Signal Sources
      • Figure 4-22. Differential Connections for Ground-Referenced Signal Sources
      • Using Non-Referenced Single-Ended (NRSE) Connections for Ground-Referenced Signal Sources
      • Figure 4-23. Single-Ended Connections for Ground-Referenced Signal Sources (NRSE Configuration)
  • Connecting Analog Input Signals on USB-6215/6216/6218 Devices
    • Taking Differential Measurements
      • Figure 4-24. Connecting to the USB-6215/6216/6218 in Differential Mode
    • Taking Referenced Single-Ended (RSE) Measurements
      • Figure 4-25. Connecting to the USB-6215/6216/6218 in RSE Mode
    • Taking Non-Referenced Single-Ended (NRSE) Measurements
      • Figure 4-26. Connecting to the USB-6215/6216/6218 in NRSE Mode
• Chapter 5 Analog Output
  • Figure 5-1. USB-621x Analog Output Circuitry
  • AO Range
  • Minimizing Glitches on the Output Signal
  • Analog Output Data Generation Methods
  • Analog Output Digital Triggering
  • Connecting Analog Output Signals
    • Figure 5-2. Analog Output Connections
  • Analog Output Timing Signals
    • Figure 5-3. Analog Output Timing Options
    • AO Start Trigger Signal
      • Using a Digital Source
      • Routing AO Start Trigger to an Output Terminal
    • AO Pause Trigger Signal
      • Figure 5-4. AO Pause Trigger Example
      • Figure 5-5. AO Pause Trigger with Other Signal Source
      • Using a Digital Source
    • AO Sample Clock Signal
      • Using an Internal Source
      • Using an External Source
      • Routing AO Sample Clock to an Output Terminal
      • Other Timing Requirements
      • Figure 5-6. AO Sample Clock and AO Start Trigger
    • AO Sample Clock Timebase Signal
  • Getting Started with AO Applications in Software
• Chapter 6 Digital I/O
  • Digital I/O on USB-6210/6211/6215/6218 Devices
    • Figure 6-1. USB-6210/6211/6215/6218 Digital I/O Circuitry
    • Static DIO on USB-6210/6211/6215/6218 Devices
    • I/O Protection on USB-6210/6211/6215/6218 Devices
    • Increasing Current Drive on USB-6210/6211/6215/6218 Devices
    • Connecting Digital I/O Signals on USB-6210/6211/6215/6218 Devices
      • Figure 6-2. USB-6210/6211/6215/6218 Digital I/O Connections
    • Getting Started with DIO Applications in Software on USB-6210/6211/6215/6218 Devices
  • Digital I/O on USB-6212/6216 Devices
    • Figure 6-3. USB-6212/6216 Digital I/O Circuitry
    • Static DIO on USB-6212/6216 Devices
    • I/O Protection on USB-6212/6216 Devices
    • Programmable Power-Up States on USB-6212/6216 Devices
    • Increasing Current Drive on USB-6212/6216 Devices
    • Connecting Digital I/O Signals on USB-6212/6216 Devices
      • Figure 6-4. USB-6212/6216 Digital I/O Connections
    • Getting Started with DIO Applications in Software on USB-6212/6216 Devices
• Chapter 7 PFI
  • Figure 7-1. USB-621x PFI Input Circuitry
  • Figure 7-2. USB-621x PFI Output Circuitry
  • Using PFI Terminals as Timing Input Signals
  • Exporting Timing Output Signals Using PFI Terminals
  • Using PFI Terminals as Static Digital I/Os
  • Connecting PFI Input Signals
    • Figure 7-3. PFI Input Signals Connections
  • PFI Filters
    • Table 7-1. Filters
    • Figure 7-4. Filter Example
  • I/O Protection
  • Programmable Power-Up States
• Chapter 8 Counters
  • Figure 8-1. USB-621x Counters
  • Counter Input Applications
    • Counting Edges
      • Single Point (On-Demand) Edge Counting
      • Figure 8-2. Single Point (On-Demand) Edge Counting
      • Figure 8-3. Single Point (On-Demand) Edge Counting with Pause Trigger
      • Buffered (Sample Clock) Edge Counting
      • Figure 8-4. Buffered (Sample Clock) Edge Counting
      • Controlling the Direction of Counting
    • Pulse-Width Measurement
      • Single Pulse-Width Measurement
      • Figure 8-5. Single Pulse-Width Measurement
      • Buffered Pulse-Width Measurement
      • Figure 8-6. Buffered Pulse-Width Measurement
    • Period Measurement
      • Single Period Measurement
      • Figure 8-7. Single Period Measurement
      • Buffered Period Measurement
      • Figure 8-8. Buffered Period Measurement
    • Semi-Period Measurement
      • Single Semi-Period Measurement
      • Buffered Semi-Period Measurement
      • Figure 8-9. Buffered Semi-Period Measurement
    • Frequency Measurement
      • Figure 8-10. Method 1
      • Figure 8-11. Method 1b
      • Figure 8-12. Method 2
      • Figure 8-13. Method 3
      • Choosing a Method for Measuring Frequency
      • Table 8-1. Frequency Measurement Method 1
      • Table 8-2. Frequency Measurement Method Comparison
    • Position Measurement
      • Measurements Using Quadrature Encoders
      • Figure 8-14. X1 Encoding
      • Figure 8-15. X2 Encoding
      • Figure 8-16. X4 Encoding
      • Figure 8-17. Channel Z Reload with X4 Decoding
      • Measurements Using Two Pulse Encoders
      • Figure 8-18. Measurements Using Two Pulse Encoders
    • Two-Signal Edge-Separation Measurement
      • Single Two-Signal Edge-Separation Measurement
      • Figure 8-19. Single Two-Signal Edge-Separation Measurement
      • Buffered Two-Signal Edge-Separation Measurement
      • Figure 8-20. Buffered Two-Signal Edge-Separation Measurement
  • Counter Output Applications
    • Simple Pulse Generation
      • Single Pulse Generation
      • Figure 8-21. Single Pulse Generation
      • Single Pulse Generation with Start Trigger
      • Figure 8-22. Single Pulse Generation with Start Trigger
      • Retriggerable Single Pulse Generation
      • Figure 8-23. Retriggerable Single Pulse Generation
    • Pulse Train Generation
      • Continuous Pulse Train Generation
      • Figure 8-24. Continuous Pulse Train Generation
    • Frequency Generation
      • Using the Frequency Generator
      • Figure 8-25. Frequency Generator Block Diagram
      • Figure 8-26. Frequency Generator Output Waveform
    • Frequency Division
    • Pulse Generation for ETS
      • Figure 8-27. Pulse Generation for ETS
  • Counter Timing Signals
    • Counter n Source Signal
      • Table 8-3. Counter Applications and Counter n Source
      • Routing a Signal to Counter n Source
      • Routing Counter n Source to an Output Terminal
    • Counter n Gate Signal
      • Routing a Signal to Counter n Gate
      • Routing Counter n Gate to an Output Terminal
    • Counter n Aux Signal
      • Routing a Signal to Counter n Aux
    • Counter n A, Counter n B, and Counter n Z Signals
      • Routing Signals to A, B, and Z Counter Inputs
    • Counter n Up_Down Signal
    • Counter n HW Arm Signal
      • Routing Signals to Counter n HW Arm Input
    • Counter n Internal Output and Counter n TC Signals
      • Routing Counter n Internal Output to an Output Terminal
    • Frequency Output Signal
      • Routing Frequency Output to a Terminal
  • Default Counter/Timer Pinouts
    • Table 8-4. Default NI-DAQmx Counter/Timer Pins for USB-6210/6211/6215 Devices
  • Counter Triggering
  • Other Counter Features
    • Sample Clock
      • Figure 8-28. Sample Clock Example
    • Cascading Counters
    • Counter Filters
      • Table 8-5. Filters
      • Figure 8-29. Filter Example
    • Prescaling
      • Figure 8-30. Prescaling
    • Duplicate Count Prevention
      • Example Application That Works Correctly (No Duplicate Counting)
      • Figure 8-31. Duplicate Count Prevention Example
      • Example Application That Works Incorrectly (Duplicate Counting)
      • Figure 8-32. Duplicate Count Example
      • Example Application That Prevents Duplicate Count
      • Figure 8-33. Duplicate Count Prevention Example
      • Enabling Duplicate Count Prevention in NI-DAQmx
• Chapter 9 Isolation and Digital Isolators on USB-6215/6216/6218 Devices
  • Figure 9-1. USB-6215/6216/6218 Block Diagram
  • Digital Isolation
  • Benefits of an Isolated DAQ Device
  • Reducing Common-Mode Noise
    • Creating an AC Return Path
      • Isolated Systems
      • Non-Isolated Systems
• Chapter 10 Digital Routing and Clock Generation
  • 80 MHz Timebase
  • 20 MHz Timebase
  • 100 kHz Timebase
• Chapter 11 Bus Interface
  • USB Signal Stream
  • Data Transfer Methods
    • Changing Data Transfer Methods
• Chapter 12 Triggering
  • Triggering with a Digital Source
    • Figure 12-1. Falling-Edge Trigger
• Appendix A Device-Specific Information
  • USB-6210
    • Figure A-1. USB-6210 Pinout
    • Table A-1. Default NI-DAQmx Counter/Timer Pins
  • USB-6211/6215
    • Figure A-2. USB-6211/6215 Pinout
    • Table A-2. Default NI-DAQmx Counter/Timer Pins
  • USB-6212/6216 Screw Terminal
    • Figure A-3. USB-6212/6216 Screw Terminal Pinout
    • Table A-3. Default NI-DAQmx Counter/Timer Pins
  • USB-6212/6216 Mass Termination
    • Figure A-4. USB-6212/6216 Mass Termination Pinout
    • Table A-4. Default NI-DAQmx Counter/Timer Pins
  • USB-6218
    • Figure A-5. USB-6218 Pinout
    • Table A-5. Default NI-DAQmx Counter/Timer Pins
• Appendix B Troubleshooting
  • Figure B-1. AI Sample Clock and AI Convert Clock
• Appendix C Technical Support and Professional Services
• Glossary
  • Symbols
  • A
  • B-C
  • D
  • E
  • F
  • G-H
  • I
  • L-M
  • N-P
  • Q-R
  • S
  • T
  • U-V
  • W
• Index
  • Symbols
  • Numerics
  • A
  • B-C
  • D
  • E-G
  • H-M
  • N-P
  • Q-S
  • T
  • U
  • W-X