National-instruments Data Acquisition Device NI USB-621x Manual do Utilizador

DAQ M SeriesNI USB-621x User ManualBus-Powered M Series USB DevicesNI USB-621x User Manualni.com/manualsDeutschFrançaisMarch 2008371931E-01

ContentsNI USB-621x User Manual x ni.comOther Counter Features...

Chapter 8 Counters© National Instruments Corporation 8-7 NI USB-621x User ManualBuffered Period MeasurementBuffered period measurement is similar to s

Chapter 8 CountersNI USB-621x User Manual 8-8 ni.comcondition is not met, the counter returns a zero. Refer to the Duplicate Count Prevention section

Chapter 8 Counters© National Instruments Corporation 8-9 NI USB-621x User ManualFigure 8-9 shows an example of a buffered semi-period measurement.Figu

Chapter 8 CountersNI USB-621x User Manual 8-10 ni.comYou can configure the counter to measure one period of the gate signal. The frequency of F1 is th

Chapter 8 Counters© National Instruments Corporation 8-11 NI USB-621x User ManualAverage the remaining K period measurements to determine the average

Chapter 8 CountersNI USB-621x User Manual 8-12 ni.comFigure 8-12 illustrates this method. Another option would be to measure the width of a known peri

Chapter 8 Counters© National Instruments Corporation 8-13 NI USB-621x User ManualFigure 8-13. Method 3Then route the Counter 0 Internal Output signal

Chapter 8 CountersNI USB-621x User Manual 8-14 ni.com80 MHz Timebase. Your measurement may return 1600 ± 1 cycles depending on the phase of the signal

Chapter 8 Counters© National Instruments Corporation 8-15 NI USB-621x User ManualTable 8-2 summarizes some of the differences in methods of measuring

Chapter 8 CountersNI USB-621x User Manual 8-16 ni.comFigure 8-14. X1 Encoding• X2 Encoding—The same behavior for X1 encoding holds for X2 encoding ex

Contents© National Instruments Corporation xi NI USB-621x User ManualAppendix ADevice-Specific InformationUSB-6210 ...

Chapter 8 Counters© National Instruments Corporation 8-17 NI USB-621x User Manualhigh during at least a portion of the phase you specify for reload. F

Chapter 8 CountersNI USB-621x User Manual 8-18 ni.comTwo-Signal Edge-Separation MeasurementTwo-signal edge-separation measurement is similar to pulse-

Chapter 8 Counters© National Instruments Corporation 8-19 NI USB-621x User ManualFigure 8-19 shows an example of a single two-signal edge-separation m

Chapter 8 CountersNI USB-621x User Manual 8-20 ni.comCounter Output ApplicationsSimple Pulse GenerationSingle Pulse GenerationThe counter can output a

Chapter 8 Counters© National Instruments Corporation 8-21 NI USB-621x User ManualFigure 8-22 shows a generation of a pulse with a pulse delay of four

Chapter 8 CountersNI USB-621x User Manual 8-22 ni.comPulse Train GenerationContinuous Pulse Train GenerationThis function generates a train of pulses

Chapter 8 Counters© National Instruments Corporation 8-23 NI USB-621x User ManualFrequency GenerationYou can generate a frequency by using a counter i

Chapter 8 CountersNI USB-621x User Manual 8-24 ni.comFrequency Output can be routed out to any output PFI terminal. All PFI terminals are set to high-

Chapter 8 Counters© National Instruments Corporation 8-25 NI USB-621x User Manualfor ETS; the delay from the trigger to the pulse increases after each

Chapter 8 CountersNI USB-621x User Manual 8-26 ni.comCounter n Source SignalThe selected edge of the Counter n Source signal increments and decrements

© National Instruments Corporation xiii NI USB-621x User ManualAbout This ManualThe NI USB-621x User Manual contains information about using the Natio

Chapter 8 Counters© National Instruments Corporation 8-27 NI USB-621x User ManualCounter n Gate SignalThe Counter n Gate signal can perform many diffe

Chapter 8 CountersNI USB-621x User Manual 8-28 ni.com• AI Reference Trigger (ai/ReferenceTrigger)• AI Start Trigger (ai/StartTrigger)In addition, Coun

Chapter 8 Counters© National Instruments Corporation 8-29 NI USB-621x User ManualRouting Signals to Counter n HW Arm InputAny of the following signals

Chapter 8 CountersNI USB-621x User Manual 8-30 ni.comDefault Counter/Timer PinoutsBy default, NI-DAQmx routes the counter/timer inpu ts and outputs to

Chapter 8 Counters© National Instruments Corporation 8-31 NI USB-621x User ManualCounter TriggeringCounters support three different triggering actions

Chapter 8 CountersNI USB-621x User Manual 8-32 ni.comOther Counter FeaturesSample ClockWhen taking counter measurements, you can enable a sample clock

Chapter 8 Counters© National Instruments Corporation 8-33 NI USB-621x User ManualCascading CountersYou can internally route the Counter n Internal Out

Chapter 8 CountersNI USB-621x User Manual 8-34 ni.comFigure 8-29. Filter ExampleEnabling filters introduces jitter on the input signal. For the 125 n

Chapter 8 Counters© National Instruments Corporation 8-35 NI USB-621x User ManualPrescaling is not available if the counter Source is one of the inter

Chapter 8 CountersNI USB-621x User Manual 8-36 ni.comthe first rising Source edge after the rising edge of Gate. The details of when exactly the count

About This ManualNI USB-621x User Manual xiv ni.comPlatform Text in this font denotes a specific platform and indicates that the text following it app

Chapter 8 Counters© National Instruments Corporation 8-37 NI USB-621x User ManualFigure 8-33. Duplicate Count Prevention ExampleEven if the Source pu

© National Instruments Corporation 9-1 NI USB-621x User Manual9Isolation and Digital Isolators on USB-6215/6216/6218 DevicesUSB-6215/6216/6218 devices

Chapter 9 Isolation and Digital Isolators on USB-6215/6216/6218 Devices© National Instruments Corporation 9-2 NI USB-621x User ManualThe non-isolated

Chapter 9 Isolation and Digital Isolators on USB-6215/6216/6218 DevicesNI USB-621x User Manual 9-3 ni.comof error and noise, are the result of a measu

Chapter 9 Isolation and Digital Isolators on USB-6215/6216/6218 Devices© National Instruments Corporation 9-4 NI USB-621x User ManualIsolated SystemsA

© National Instruments Corporation 10-1 NI USB-621x User Manual10Digital Routing and Clock GenerationThe digital routing circuitry has the following m

© National Instruments Corporation 11-1 NI USB-621x User Manual11Bus InterfaceThe bus interface circuitry of USB-621x devices efficiently moves data b

Chapter 11 Bus InterfaceNI USB-621x User Manual 11-2 ni.comOutput Data Generation Methods section of Chapter 5, Analog Output, for more information.Ch

© National Instruments Corporation 12-1 NI USB-621x User Manual12TriggeringA trigger is a signal that causes an action, such as starting or stopping t

Chapter 12 TriggeringNI USB-621x User Manual 12-2 ni.comYou also can program your USB-621x device to perform an action in response to a trigger from a

About This Manual© National Instruments Corporation xv NI USB-621x User ManualThe NI-DAQmx Base VI Reference Help contains VI reference and general in

© National Instruments Corporation A-1 NI USB-621x User ManualADevice-Specific InformationThis appendix contains device pinouts and other information

Appendix A Device-Specific InformationNI USB-621x User Manual A-2 ni.comUSB-6210USB-6210 PinoutFigure A-1 shows the pinout of the USB-6210.For a detai

Appendix A Device-Specific Information© National Instruments Corporation A-3 NI USB-621x User ManualNote For more information about default NI-DAQmx c

Appendix A Device-Specific InformationNI USB-621x User Manual A-4 ni.comUSB-6211/6215USB-6211/6215 PinoutFigure A-2 shows the pinout of the USB-6211 a

Appendix A Device-Specific Information© National Instruments Corporation A-5 NI USB-621x User ManualNote For more information about default NI-DAQmx c

Appendix A Device-Specific InformationNI USB-621x User Manual A-6 ni.comUSB-6212/6216 Screw TerminalUSB-6212/6216 Screw Terminal PinoutFigure A-3 show

Appendix A Device-Specific Information© National Instruments Corporation A-7 NI USB-621x User ManualNote For more information about default NI-DAQmx c

Appendix A Device-Specific InformationNI USB-621x User Manual A-8 ni.comUSB-6212/6216 Mass TerminationUSB-6212/6216 Mass Termination PinoutFigure A-4

Appendix A Device-Specific Information© National Instruments Corporation A-9 NI USB-621x User ManualFigure A-4. USB-6212/6216 Mass Termination Pinout

Appendix A Device-Specific InformationNI USB-621x User Manual A-10 ni.comNote For more information about default NI-DAQmx counter inputs, refer to Con

About This ManualNI USB-621x User Manual xvi ni.comLabWindows/CVIThe Data Acquisition book of the LabWindows/CVI Help contains measurement concepts fo

Appendix A Device-Specific Information© National Instruments Corporation A-11 NI USB-621x User ManualRefer to the SCC Advisor, available by going to n

Appendix A Device-Specific InformationNI USB-621x User Manual A-12 ni.comCustom Cabling and ConnectivityThe CA-1000 is a configurable enclosure that g

Appendix A Device-Specific Information© National Instruments Corporation A-13 NI USB-621x User ManualUSB-6218USB-6218 PinoutFigure A-5 shows the pinou

Appendix A Device-Specific InformationNI USB-621x User Manual A-14 ni.comNote For more information about default NI-DAQmx counter inputs, refer to Con

© National Instruments Corporation B-1 NI USB-621x User ManualBTroubleshootingThis section contains common questions about USB-621x devices. If your q

Appendix B TroubleshootingNI USB-621x User Manual B-2 ni.comare various methods of achieving this reference while maintaining a high common-mode rejec

Appendix B Troubleshooting© National Instruments Corporation B-3 NI USB-621x User ManualAnalog OutputI am seeing glitches on the output signal. How ca

© National Instruments Corporation C-1 NI USB-621x User ManualCTechnical Support and Professional ServicesVisit the following sections of the National

Appendix C Technical Support and Professional ServicesNI USB-621x User Manual C-2 ni.com• Declaration of Conformity (DoC)—A DoC is our claim of compli

© National Instruments Corporation G-1 NI USB-621x User ManualGlossary Symbol Prefix Valueppico10–12nnano10–9μ micro 10–6m milli 10–3k kilo 103Mmega10

About This Manual© National Instruments Corporation xvii NI USB-621x User ManualANSI C without NI Application SoftwareThe NI-DAQmx Help contains API o

GlossaryNI USB-621x User Manual G-2 ni.comAA Amperes—the unit of electric current.A/D Analog-to-Digital. Most often used as A/D converter.AC Alternati

Glossary© National Instruments Corporation G-3 NI USB-621x User Manualarm The process of getting an instrument ready to perform a function. For exampl

GlossaryNI USB-621x User Manual G-4 ni.comCE European emissions control standard.channel Pin or wire lead to which you apply or from which you read th

Glossary© National Instruments Corporation G-5 NI USB-621x User ManualDD GND Digital ground signal.DAC Digital-to-Analog Converter—An electronic devic

GlossaryNI USB-621x User Manual G-6 ni.comDIFF Differential mode—An analog input mode consisting of two terminals, both of which are isolated from com

Glossary© National Instruments Corporation G-7 NI USB-621x User Manualencoder A device that converts linear or rotary displacement into digital or pul

GlossaryNI USB-621x User Manual G-8 ni.comfloating signal sou rces Signal sources with voltage signals that are not connected to an absolute reference

Glossary© National Instruments Corporation G-9 NI USB-621x User ManualII/O Input/Output—The transfer of data to/from a computer system involving commu

GlossaryNI USB-621x User Manual G-10 ni.comLLabVIEW A graphical programming language.LED Light-Emitting Diode—A semiconductor light source.lowpass fil

Glossary© National Instruments Corporation G-11 NI USB-621x User ManualmuxMultiplexer—A set of semiconductor or electromechanical switches arranged to

About This ManualNI USB-621x User Manual xviii ni.comInsert the CD, open the Device Documentation directory, and double-click the Device Documents sho

GlossaryNI USB-621x User Manual G-12 ni.comPFI Programmable Function Interface.PGIA Programmable Gain Instrumentation Amplifier.physical channel See c

Glossary© National Instruments Corporation G-13 NI USB-621x User ManualRSE Referenced Single-Ended mode—All measurements are made with respect to a co

GlossaryNI USB-621x User Manual G-14 ni.comsingle-buffered Describes a device that acquires a specified number of samples from one or more channels an

Glossary© National Instruments Corporation G-15 NI USB-621x User ManualtoutOutput delay time.transducer A device that responds to a physical stimulu s

GlossaryNI USB-621x User Manual G-16 ni.comVmMeasured voltage.VOHVo l t s , o utput high.VOLVo l t s , o utput low.VoutVo l t s o ut.VsSignal sourc

© National Instruments Corporation I-1 NI USB-621x User ManualIndexSymbols+5 V powerinput, 3-3output, 3-3source, 3-3Numerics100 kHz Timebase, 10-120 M

IndexNI USB-621x User Manual I-2 ni.comAI Reference Trigger, 4-21AI Sample Clock, 4-14AI Sample Clock Timebase, 4-15AI Start Trigger, 4-20analog outpu

Index© National Instruments Corporation I-3 NI USB-621x User Manualconnectinganalog input signals on USB-6210/6211/6212 devices, 4-23analog input sign

IndexNI USB-621x User Manual I-4 ni.comcrosstalk when sampling multiple channels, B-1custom cabling, 2-4DDACs, 5-1DAQhardware, 2-1system, 2-1DAQ-STC2,

Index© National Instruments Corporation I-5 NI USB-621x User Manualdouble-buffered acquisition, 4-9drivers (NI resources), C-1duplicate count preventi

© National Instruments Corporation 1-1 NI USB-621x User Manual1Getting StartedNI USB-621x devices feature up to 32 analog input (AI) channels, up to t

IndexNI USB-621x User Manual I-6 ni.comground-referenced signal sourcesconnecting, 4-31description, 4-31using in differential mode, 4-33using in NRSE

Index© National Instruments Corporation I-7 NI USB-621x User Manualmethods, data transfer, 11-1minimizingglitches on the output signal, 5-2output sign

IndexNI USB-621x User Manual I-8 ni.compins, default, 8-30position measurement, 8-15power, +5 V, 3-3input, 3-3output, 3-3power-up states, 7-6USB-6212/

Index© National Instruments Corporation I-9 NI USB-621x User ManualAO Pause Trigger, 5-6AO Sample Clock, 5-7AO Sample Clock Timebase, 5-8AO Start Trig

IndexNI USB-621x User Manual I-10 ni.comtiming output signals, exporting using PFI terminals, 7-3training, xviiitraining and certification (NI resourc

Index© National Instruments Corporation I-11 NI USB-621x User Manualmass termination variant cables and accessories, 2-4panel mounting, 1-5specificati

Chapter 1 Getting StartedNI USB-621x User Manual 1-2 ni.comDevice SpecificationsRefer to the NI USB-621x Specifications, available on the NI-DAQ Devic

SupportWorldwide Technical Support and Product Informationni.comNational Instruments Corporate Headquarters11500 North Mopac Expressway Austin, Texas

Chapter 1 Getting Started© National Instruments Corporation 1-3 NI USB-621x User ManualUSB Cable Strain ReliefYou can provide strain relief for the US

Chapter 1 Getting StartedNI USB-621x User Manual 1-4 ni.comMounting the USB-621xYou can use the USB-621x on a desktop or mount it to a standard DIN ra

Chapter 1 Getting Started© National Instruments Corporation 1-5 NI USB-621x User ManualPanel MountingTo mount the USB-621x to a board or panel, comple

Chapter 1 Getting StartedNI USB-621x User Manual 1-6 ni.com3. Remove the USB cable from the connector on the USB-621x.4. Screw a #8 or M4 screw into t

© National Instruments Corporation 2-1 NI USB-621x User Manual2DAQ System OverviewFigure 2-1 shows a typical DAQ system, which includes the USB-621x d

Chapter 2 DAQ System OverviewNI USB-621x User Manual 2-2 ni.comFigure 2-2. USB-621x Block DiagramDAQ-STC2The DAQ-STC2 implements a high-performance d

Chapter 2 DAQ System Overview© National Instruments Corporation 2-3 NI USB-621x User ManualFactory-calibration constants are permanently stored in an

Chapter 2 DAQ System OverviewNI USB-621x User Manual 2-4 ni.com•If you are using other application software, refer to Common Sensors in the NI-DAQmx H

Chapter 2 DAQ System Overview© National Instruments Corporation 2-5 NI USB-621x User ManualProgramming Devices in SoftwareNational Instruments measure

© National Instruments Corporation 3-1 NI USB-621x User Manual3Connector and LED InformationThe I/O Connector Signal Descriptions and +5 V Power secti

Important InformationWarrantyThe NI USB-6210, NI USB-6211, NI USB-6212, NI USB-6215, NI USB-6216, and NI USB-6218 are warranted against defects in ma

Chapter 3 Connector and LED Information© National Instruments Corporation 3-2 NI USB-621x User ManualAO <0..1> AO GND Output Analog Output Chann

Chapter 3 Connector and LED InformationNI USB-621x User Manual 3-3 ni.com+5 V PowerThe +5 V terminals on the I/O connector can be use as either an out

Chapter 3 Connector and LED Information© National Instruments Corporation 3-4 NI USB-621x User Manual3. Replace the broken fuse in the socket. Figure

Chapter 3 Connector and LED InformationNI USB-621x User Manual 3-5 ni.comPWR/ACT LED IndicatorThe PWR/ACT LED indicator indicates device status. Table

© National Instruments Corporation 4-1 NI USB-621x User Manual4Analog InputFigure 4-1 shows the analog input circuitry of USB-621x devices.Figure 4-1.

Chapter 4 Analog InputNI USB-621x User Manual 4-2 ni.comminimizes settling times for all input ranges. The NI-PGIA can amplify or attenuate an AI sign

Chapter 4 Analog Input© National Instruments Corporation 4-3 NI USB-621x User ManualFor more information about setting ranges, refer to the NI-DAQmx H

Chapter 4 Analog InputNI USB-621x User Manual 4-4 ni.comwith this amplified voltage. The amount of amplification (the gain) is determined by the analo

Chapter 4 Analog Input© National Instruments Corporation 4-5 NI USB-621x User ManualConfiguring AI Ground-Reference Settings in SoftwareYou can progra

Chapter 4 Analog InputNI USB-621x User Manual 4-6 ni.comof your measurements. To ensure fast settling times, you should do the following (in order of

ComplianceCompliance with FCC/Canada Radio Frequency Interference RegulationsDetermining FCC ClassThe Federal Communications Commission (FCC) has rul

Chapter 4 Analog Input© National Instruments Corporation 4-7 NI USB-621x User Manualapproximately 4 V step from 4 V to 1 mV is 1,000% of the new full-

Chapter 4 Analog InputNI USB-621x User Manual 4-8 ni.com• Avoid Scanning Faster Than Necessary—Designing your system to scan at slower speeds gives th

Chapter 4 Analog Input© National Instruments Corporation 4-9 NI USB-621x User Manual• Hardware-Timed Acquisitions—With hardware-timed acquisitions, a

Chapter 4 Analog InputNI USB-621x User Manual 4-10 ni.comAnalog Input Digital TriggeringAnalog input supports three different triggering actions:• Sta

Chapter 4 Analog Input© National Instruments Corporation 4-11 NI USB-621x User ManualAnalog Input Timing SignalsIn order to provide all of the timing

Chapter 4 Analog InputNI USB-621x User Manual 4-12 ni.comFigure 4-5. Interval SamplingAI Convert Clock controls the Convert Period, which is determin

Chapter 4 Analog Input© National Instruments Corporation 4-13 NI USB-621x User ManualPretriggered data acquisition allows you to view data that is acq

Chapter 4 Analog InputNI USB-621x User Manual 4-14 ni.comAI Sample Clock SignalUse the AI Sample Clock (ai/SampleClock) signal to initiate a set of me

Chapter 4 Analog Input© National Instruments Corporation 4-15 NI USB-621x User Manualsoftware or hardware can stop it once a finite acquisition comple

Chapter 4 Analog InputNI USB-621x User Manual 4-16 ni.comAI Convert Clock SignalUse the AI Convert Clock (ai/ConvertClock) signal to initiate a single

© National Instruments Corporation v NI USB-621x User ManualContentsAbout This ManualConventions ...

Chapter 4 Analog Input© National Instruments Corporation 4-17 NI USB-621x User ManualUsing a Delay from Sample Clock to Convert ClockWhen using an int

Chapter 4 Analog InputNI USB-621x User Manual 4-18 ni.comFigure 4-10. AI Sample Clock Too Fast For AI Convert Clock; AI Sample Clock Pulses Are Gated

Chapter 4 Analog Input© National Instruments Corporation 4-19 NI USB-621x User ManualFigure 4-13. AI Sample Clock and AI Convert Clock Properly Match

Chapter 4 Analog InputNI USB-621x User Manual 4-20 ni.comThe polarity of AI Hold Complete Event is software-selectable, but is typically configured so

Chapter 4 Analog Input© National Instruments Corporation 4-21 NI USB-621x User Manualcomplete description of the use of AI Start Trigger and AI Refere

Chapter 4 Analog InputNI USB-621x User Manual 4-22 ni.comUsing a Digital SourceTo use AI Reference Trigger with a digital source, specify a source and

Chapter 4 Analog Input© National Instruments Corporation 4-23 NI USB-621x User ManualNote For more information about programming analog input applicat

Chapter 4 Analog InputNI USB-621x User Manual 4-24 ni.comTable 4-2. USB-6210/6211/6212 Analog Input ConfigurationAI Ground-Reference Setting*Floating

Chapter 4 Analog Input© National Instruments Corporation 4-25 NI USB-621x User ManualConnecting Floating Signal SourcesWhat Are Floating Signal Source

Chapter 4 Analog InputNI USB-621x User Manual 4-26 ni.comDIFF input connections are recommended for greater signal integrity for any input signal that

ContentsNI USB-621x User Manual vi ni.comChapter 4Analog InputAnalog Input Range...

Chapter 4 Analog Input© National Instruments Corporation 4-27 NI USB-621x User ManualUsing Differential Connections for Floating Signal SourcesIt is i

Chapter 4 Analog InputNI USB-621x User Manual 4-28 ni.comFigure 4-17. Differential Connections for Floating Signal Sources with Single Bias ResistorY

Chapter 4 Analog Input© National Instruments Corporation 4-29 NI USB-621x User ManualFigure 4-18. Differential Connections for Floating Signal Source

Chapter 4 Analog InputNI USB-621x User Manual 4-30 ni.comFigure 4-19. Differential Connections for AC Coupled Floating Sources with Balanced Bias Res

Chapter 4 Analog Input© National Instruments Corporation 4-31 NI USB-621x User ManualUsing the DAQ Assistant, you can configure the channels for RSE o

Chapter 4 Analog InputNI USB-621x User Manual 4-32 ni.comdifference can appear as measurement error. Follow the connection instructions for grounded s

Chapter 4 Analog Input© National Instruments Corporation 4-33 NI USB-621x User ManualIn the single-ended modes, more electrostatic and magnetic noise

Chapter 4 Analog InputNI USB-621x User Manual 4-34 ni.comFigure 4-22. Differential Connections for Ground-Referenced Signal SourcesWith this type of

Chapter 4 Analog Input© National Instruments Corporation 4-35 NI USB-621x User ManualFigure 4-23. Single-Ended Connections for Ground-Referenced Sign

Chapter 4 Analog InputNI USB-621x User Manual 4-36 ni.comConnecting Analog Input Signals on USB-6215/6216/6218 DevicesYou can connect the USB-6215/621

Contents© National Instruments Corporation vii NI USB-621x User ManualUsing Non-Referenced Single-Ended (NRSE) Connections for Floating Signal Sources

Chapter 4 Analog Input© National Instruments Corporation 4-37 NI USB-621x User ManualThe differential connection configuration allows the common-mode

Chapter 4 Analog InputNI USB-621x User Manual 4-38 ni.comTaking Non-Referenced Single-Ended (NRSE) MeasurementsTo reach a compromise between RSE and d

© National Instruments Corporation 5-1 NI USB-621x User Manual5Analog OutputMost USB-621x devices have analog output functionality. USB-621x devices t

Chapter 5 Analog OutputNI USB-621x User Manual 5-2 ni.com• AO Sample Clock—The AO Sample Clock signal reads a sample from the DAC FIFO and generates t

Chapter 5 Analog Output© National Instruments Corporation 5-3 NI USB-621x User Manual– Hardware-timed acquisitions can use hardware triggering.Hardwar

Chapter 5 Analog OutputNI USB-621x User Manual 5-4 ni.comA digital trigger can initiate these actions on USB-621x devices. Refer to the AO Start Trigg

Chapter 5 Analog Output© National Instruments Corporation 5-5 NI USB-621x User ManualFigure 5-3. Analog Output Timing OptionsUSB-621x devices feature

Chapter 5 Analog OutputNI USB-621x User Manual 5-6 ni.comThe source also can be one of several internal signals on your USB-621x device. Refer to Devi

Chapter 5 Analog Output© National Instruments Corporation 5-7 NI USB-621x User ManualIf you are using any signal as the source of your sample clock, t

Chapter 5 Analog OutputNI USB-621x User Manual 5-8 ni.comUsing an External SourceUse any input PFI line as the source of AO Sample Clock.Routing AO Sa

ContentsNI USB-621x User Manual viii ni.comChapter 6Digital I/ODigital I/O on USB-6210/6211/6215/6218 Devices ...

Chapter 5 Analog Output© National Instruments Corporation 5-9 NI USB-621x User Manual• (USB-6212/6216 Devices) PFI <0..15>•(USB-6218 Devices) PF

© National Instruments Corporation 6-1 NI USB-621x User Manual6Digital I/ORefer to one of the following sections, depending on you r device:• Digital

Chapter 6 Digital I/ONI USB-621x User Manual 6-2 ni.comFigure 6-1. USB-6210/6211/6215/6218 Digital I/O CircuitryThe DI terminals are named P0.<0..

Chapter 6 Digital I/O© National Instruments Corporation 6-3 NI USB-621x User ManualIncreasing Current Drive on USB-6210/6211/6215/6218 DevicesThe tota

Chapter 6 Digital I/ONI USB-621x User Manual 6-4 ni.comGetting Started with DIO Applications in Software on USB-6210/6211/6215/6218 DevicesYou can use

Chapter 6 Digital I/O© National Instruments Corporation 6-5 NI USB-621x User ManualFigure 6-3. USB-6212/6216 Digital I/O CircuitryThe following secti

Chapter 6 Digital I/ONI USB-621x User Manual 6-6 ni.comProgrammable Power-Up States on USB-6212/6216 DevicesAt system startup and reset, the hardware

Chapter 6 Digital I/O© National Instruments Corporation 6-7 NI USB-621x User ManualFigure 6-4. USB-6212/6216 Digital I/O ConnectionsCautionExceeding

© National Instruments Corporation 7-1 NI USB-621x User Manual7PFIUSB-621x devices have multiple Programmable Function Interface (PFI) signals.Each in

Chapter 7 PFINI USB-621x User Manual 7-2 ni.comFigure 7-2 shows the circuitry of an output PFI line.Figure 7-2. USB-621x PFI Output CircuitryWhen a t

Contents© National Instruments Corporation ix NI USB-621x User ManualSemi-Period Measurement ...

Chapter 7 PFI© National Instruments Corporation 7-3 NI USB-621x User Manual• AO Sample Clock Timebase (ao/SampleClockTimebase)•AO Pause Trigger (ao/Pa

Chapter 7 PFINI USB-621x User Manual 7-4 ni.comConnecting PFI Input SignalsAll PFI input connections are referenced to D GND. Figure 7-3 shows this re

Chapter 7 PFI© National Instruments Corporation 7-5 NI USB-621x User ManualAssume that an input terminal has been low for a long time. The input termi

Chapter 7 PFINI USB-621x User Manual 7-6 ni.comI/O ProtectionEach DI, DO, and PFI signal is protected against overvoltage, undervoltage, and overcurre

© National Instruments Corporation 8-1 NI USB-621x User Manual8CountersUSB-621x devices have two general-purpose 32-bit counter/timers and one frequen

Chapter 8 CountersNI USB-621x User Manual 8-2 ni.comThe counters have seven input signals, although in most applications only a few inputs are used.Fo

Chapter 8 Counters© National Instruments Corporation 8-3 NI USB-621x User ManualFigure 8-3. Single Point (On-Demand) Edge Counting with Pause Trigger

Chapter 8 CountersNI USB-621x User Manual 8-4 ni.comControlling the Direction of CountingIn edge counting applications, the counter can count up or do

Chapter 8 Counters© National Instruments Corporation 8-5 NI USB-621x User ManualFigure 8-5 shows an example of a single pulse-width measurement.Figure

Chapter 8 CountersNI USB-621x User Manual 8-6 ni.comcondition is not met, consider using duplicate count prevention, described in the Duplicate Count