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National Instruments USB-621 Series, User Manual


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Contents

©

 National Instruments Corporation

ix

NI USB-621x User Manual

Chapter 8
Counters

Co

u

nter Inp

u

t Applications............................................................................................8-2

Co

u

nting Edges ...............................................................................................8-2

Single Point (On-Demand) Edge Co

u

nting ......................................8-2

B

u

ffered (Sample Clock) Edge Co

u

nting .........................................8-3

Controlling the Direction of Co

u

nting ..............................................8-4

P

u

lse-Width Meas

u

rement ..............................................................................8-4

Single P

u

lse-Width Meas

u

rement.....................................................8-4

B

u

ffered P

u

lse-Width Meas

u

rement.................................................8-5

Period Meas

u

rement........................................................................................8-6

Single Period Meas

u

rement ..............................................................8-6

B

u

ffered Period Meas

u

rement ..........................................................8-7

Semi-Period Meas

u

rement ..............................................................................8-8

Single Semi-Period Meas

u

rement.....................................................8-8

B

u

ffered Semi-Period Meas

u

rement.................................................8-9

Freq

u

ency Meas

u

rement .................................................................................8-10

Choosing a Method for Meas

u

ring Freq

u

ency .................................8-14

Position Meas

u

rement .....................................................................................8-15

Meas

u

rements Using Q

u

adrat

u

re Encoders ......................................8-16

Meas

u

rements Using Two P

u

lse Encoders .......................................8-18

B

u

ffered (Sample Clock) Position Meas

u

rement .............................8-18

Two-Signal Edge-Separation Meas

u

rement....................................................8-19

Single Two-Signal Edge-Separation Meas

u

rement ..........................8-20

B

u

ffered Two-Signal Edge-Separation Meas

u

rement ......................8-20

Co

u

nter O

u

tp

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t Applications .........................................................................................8-21

Simple P

u

lse Generation .................................................................................8-21

Single P

u

lse Generation ....................................................................8-21

Single P

u

lse Generation with Start Trigger ......................................8-22

Retriggerable Single P

u

lse Generation .............................................8-22

P

u

lse Train Generation ....................................................................................8-23

Contin

u

o

u

s P

u

lse Train Generation ..................................................8-23

Finite P

u

lse Train Generation ...........................................................8-24

Freq

u

ency Generation .....................................................................................8-25

Using the Freq

u

ency Generator ........................................................8-25

Freq

u

ency Division .........................................................................................8-26

P

u

lse Generation for ETS................................................................................8-26

Co

u

nter Timing Signals .................................................................................................8-27

Co

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nter 

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 So

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rce Signal..................................................................................8-28

Ro

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ting a Signal to Co

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 So

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Ro

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ting Co

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Summary of Contents for USB-621 Series

Page 1: ...nal Instruments USB 6210 Manual Get Pricing Availability at ApexWaves com Call Today 1 800 915 6216 Email sales apexwaves com https www apexwaves com modular systems national instruments m series USB...

Page 2: ...DAQ M Series NI USB 621x User Manual Bus Powered M Series USB Devices NI USB 621x User Manual ni com manuals Deutsch Fran ais April 2009 371931F 01...

Page 3: ...banon 961 0 1 33 28 28 Malaysia 1800 887710 Mexico 01 800 010 0793 Netherlands 31 0 348 433 466 New Zealand 0800 553 322 Norway 47 0 66 90 76 60 Poland 48 22 328 90 10 Portugal 351 210 311 210 Russia...

Page 4: ...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 National Instrument...

Page 5: ...Pinouts 1 2 Device Specifications 1 2 Applying Signal Labels to the USB 621x 1 3 USB Cable Strain Relief 1 4 Mounting the USB 621x 1 6 Desktop Use 1 6 DIN Rail Mounting 1 6 Panel Mounting 1 7 USB Devi...

Page 6: ...4 11 AI Sample Clock Signal 4 14 Using an Internal Source 4 14 Using an External Source 4 14 Routing AI Sample Clock to an Output Terminal 4 14 Other Timing Requirements 4 14 AI Sample Clock Timebase...

Page 7: ...enced Signal Sources 4 31 When to Use Differential Connections with Ground Referenced Signal Sources 4 32 When to Use Non Referenced Single Ended Connections with Ground Referenced Signal Sources 4 32...

Page 8: ...nnecting Digital I O Signals on USB 6210 6211 6215 6218 Devices 6 3 Getting Started with DIO Applications in Software on USB 6210 6211 6215 6218 Devices 6 4 Digital I O on USB 6212 6216 Devices 6 4 St...

Page 9: ...t 8 15 Measurements Using Quadrature Encoders 8 16 Measurements Using Two Pulse Encoders 8 18 Buffered Sample Clock Position Measurement 8 18 Two Signal Edge Separation Measurement 8 19 Single Two Sig...

Page 10: ...quency Output Signal 8 31 Routing Frequency Output to a Terminal 8 31 Default Counter Timer Pinouts 8 32 Counter Triggering 8 33 Other Counter Features 8 34 Sample Clock 8 34 Cascading Counters 8 35 C...

Page 11: ...am 11 1 Data Transfer Methods 11 1 Changing Data Transfer Methods 11 2 Chapter 12 Triggering Triggering with a Digital Source 12 1 Appendix A Device Specific Information USB 6210 A 2 USB 6211 6215 A 4...

Page 12: ...t A 2 Figure A 2 USB 6211 6215 Pinout A 4 Figure A 3 USB 6212 6216 Screw Terminal Pinout A 6 Figure A 4 USB 6212 6216 Mass Termination Pinout A 9 Figure A 5 USB 6212 6216 BNC Top Panel and Pinout A 14...

Page 13: ...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 selec...

Page 14: ...AQmx for USB Devices Getting Started Guide describes how to install your NI DAQmx for Windows software your NI DAQmx supported DAQ device and how to confirm that your device is operating properly Sele...

Page 15: ...ence Help contains C reference and general information about measurement concepts In Windows select Start All Programs National Instruments NI DAQmx Base Documentation C Function Reference Help Note A...

Page 16: ...ins measurement concepts for NI DAQmx This book also contains Taking an NI DAQmx Measurement in LabWindows CVI which includes step by step instructions about creating a measurement task using the DAQ...

Page 17: ...l Instruments data acquisition devices to develop instrumentation acquisition and control applications Select Start All Programs National Instruments NI DAQ NI DAQmx C Reference Help NET Languages wit...

Page 18: ...ce Documentation directory and double click the Device Documents shortcut for your language to find view and print device documents Training Courses If you need more help getting started developing an...

Page 19: ...de which you can download from ni com manuals offers NI DAQmx users step by step instructions for installing software and hardware configuring channels and tasks and getting started developing an appl...

Page 20: ...libration using Measurement Automation Explorer MAX by completing the following steps 1 Launch MAX 2 Select My System Devices and Interfaces NI DAQmx Devices your device 3 Initiate self calibration us...

Page 21: ...labels with pin numbers or signal names or blank labels Choose one of the labels align the correct label with the terminals printed on the top panel of your device or the 16 position combicon connecto...

Page 22: ...e the USB cable groove that matches your USB cable size as shown in Figure 1 2a Zip Tie Method USB 621x Screw Terminal Mass Termination Devices Thread a zip tie through the zip tie bar on the undersid...

Page 23: ...e as shown in Figure 1 3 Figure 1 3 USB Cable Strain Relief on USB 621x BNC Devices Note You can provide cable management for signal wires to from the screw terminals and BNC connectors on USB 621x BN...

Page 24: ...Screw Terminal Mass Termination Devices For secure desktop use adhere the supplied rubber non skid feet to the underside of the USB 621x device as shown in Figure 1 4 Note Do not apply the rubber fee...

Page 25: ...he device Note Apply strain relief as described in the USB Cable Strain Relief section before panel mounting the USB 621x 1 Download and print the panel mounting template PDF attached in the Knowledge...

Page 26: ...h the USB 621x top screw hole into the panel USB Device Security Cable Slot USB 621x BNC Devices The security cable slot shown in Figure 1 3 allows you to attach an optional antitheft device to your U...

Page 27: ...ccessory connection The following sections contain more information about the components of a typical DAQ system Figure 2 1 Components of a Typical DAQ System DAQ Hardware DAQ hardware digitizes signa...

Page 28: ...er timer modules with hardware gating Static DI DO and DIO signals USB Hi Speed 2 0 interface Up to four USB Signal Streams for acquisition and generation functions Calibration Circuitry The USB 621x...

Page 29: ...nd multiplexing In addition many transducers require excitation currents or voltages bridge completion linearization or high amplification for proper and accurate operation Therefore most computer bas...

Page 30: ...B 621x Mass Termination devices BNC Cables for USB 621x BNC Devices Use standard BNC cables with the USB 621x BNC device The BNC Male Plug to BNC Male Plug Cables Kit part number 779697 01 contains fo...

Page 31: ...ples to help you get started developing an application You can modify example code and save it in an application You can use examples to develop a new application or add example code to an existing ap...

Page 32: ...round These terminals are the reference point for single ended AI measurements in RSE mode and the bias current return point for differential measurements All three ground references AI GND AO GND and...

Page 33: ...P1 0 7 D GND Output USB 6210 6211 6215 6218 Devices Programmable Function Interface or Static Digital Output Channels 0 to 7 You can route many different internal AI AO or counter timer outputs to ea...

Page 34: ...t them from short circuit conditions1 If your USB 621x device has more than one 5 V terminal you can connect the external power supply to one terminal and use the other as a power source USER USB 621x...

Page 35: ...to ni com info and entering the info code earthground You can attach a wire to the ground lug screw of any USB 621x BNC device as shown in Figure 3 1 Figure 3 1 Grounding a USB 621x BNC Device throug...

Page 36: ...ion Fuse Location 4 Replace the device top and reattach with the screws Note Unscrewing and reinstalling the thread forming screws over time will produce a compromised connection between the device to...

Page 37: ...D Status LED State Device Status Not lit Device not powered or device error Refer to ni com support if device is powered On not blinking Device error Refer to ni com support Single blink Operating nor...

Page 38: ...Reference Settings section Also refer to Appendix A Device Specific Information for device I O connector pinouts Mux Each USB 621x device has one analog to digital converter ADC The multiplexers mux...

Page 39: ...is lost USB 621x devices can handle multiple A D conversion operations with DMA interrupts or programmed I O Isolation Barrier and Digital Isolators Refer to Chapter 9 Isolation and Digital Isolators...

Page 40: ...SENSE input The AI ground reference setting determines how you should connect your AI signals to the USB 621x device For more information refer to one of the following sections depending on your devi...

Page 41: ...ferred to as AI terminal configuration Caution The maximum input voltages rating of AI signals with respect to AI GND and for differential signals with respect to each other are listed in the NI USB 6...

Page 42: ...tage measurement using the NI DAQmx C API set the terminalConfig property Refer to the NI DAQmx C Reference Help for more information Multichannel Scanning Considerations USB 621x devices can scan mul...

Page 43: ...l to your DAQ device to decrease the impedance seen by the DAQ device Refer to the KnowledgeBase document Decreasing the Source Impedance of an Analog Input Signal by going to ni com info and entering...

Page 44: ...4 V signal is connected to channel 0 and a 1 mV signal is connected to channel 1 Suppose the input range for channel 0 is 10 V to 10 V and the input range of channel 1 is 200 mV to 200 mV You can conn...

Page 45: ...settle from 8 s to 4 s In some cases the slower scan rate system returns more accurate results Example 2 If the time relationship between channels is not critical you can sample from the same channel...

Page 46: ...ne point at a time One property of buffered I O operations is the sample mode The sample mode can be either finite or continuous Finite sample mode acquisition refers to the acquisition of a specific...

Page 47: ...routing in general Minimize noise pickup and maximize measurement accuracy by taking the following precautions Use differential AI connections to reject common mode noise Use individually shielded twi...

Page 48: ...gure 4 4 Analog Input Timing Options USB 621x devices use AI Sample Clock ai SampleClock and AI Convert Clock ai ConvertClock to perform interval sampling As Figure 4 5 shows AI Sample Clock controls...

Page 49: ...r two channels at 125 kS s per channel illustrates the relationship Posttriggered data acquisition allows you to view only data that is acquired after a trigger event is received A typical posttrigger...

Page 50: ...e Clock until the value reaches zero The sample counter is then loaded with the number of posttriggered samples in this example three Figure 4 7 Pretriggered Data Acquisition Example If an AI Referenc...

Page 51: ...mple clock timebase Using an External Source Use any input PFI line as the source of AI Sample Clock Routing AI Sample Clock to an Output Terminal You can route AI Sample Clock out to any output PFI t...

Page 52: ...Convert Clock Signal section for more information about the timing requirements between AI Convert Clock and AI Sample Clock Figure 4 8 shows the relationship of AI Sample Clock to AI Start Trigger F...

Page 53: ...ng NI DAQmx chooses the conversion rate so that the AI Convert Clock pulses are evenly spaced throughout the sample To explicitly specify the conversion rate use AI Convert Clock Rate DAQmx Timing pro...

Page 54: ...s are met For example the device ignores both AI Sample Clock and AI Convert Clock until it receives a valid AI Start Trigger signal Once the device recognizes an AI Sample Clock pulse it ignores subs...

Page 55: ...erly Matched Leads To Aperiodic Sampling Figure 4 13 AI Sample Clock and AI Convert Clock Properly Matched AI Sample Clock AI Convert Clock Sample 1 Sample 2 Sample 3 Channel Measured 1 2 3 0 1 2 3 0...

Page 56: ...or AI Convert Clock Use one of the following signals as the source of AI Convert Clock Timebase AI Sample Clock Timebase 20 MHz Timebase AI Convert Clock Timebase is not available as an output on the...

Page 57: ...can be any of the following signals USB 6210 6211 6215 Devices PFI 0 3 USB 6212 6216 Devices PFI 0 15 USB 6218 Devices PFI 0 3 PFI 8 11 Counter n Internal Output The source also can be one of several...

Page 58: ...nce trigger condition If the reference trigger condition occurs before the DAQ device captures the specified number of pretrigger samples the DAQ device ignores the condition If the buffer becomes ful...

Page 59: ...o pause and resume a measurement acquisition The internal sample clock pauses while the external trigger signal is active and resumes when the signal is inactive You can program the active level of th...

Page 60: ...programming analog input applications and triggers in software refer to the NI DAQmx Help or the LabVIEW Help in version 8 0 or later Connecting Analog Input Signals on USB 6210 6211 6212 Devices Tab...

Page 61: ...tions of the RSE NRSE and DIFF modes and software considerations Refer to the Connecting Ground Referenced Signal Sources section for more information Note USB 621x BNC Devices Refer to the appropriat...

Page 62: ...ter than 3 m 10 ft The input signal requires a separate ground reference point or return signal The signal leads travel through noisy environments Two analog input channels AI and AI are available for...

Page 63: ...Single Ended Connections with Floating Signal Sources Only use non referenced single ended input connections if the input signal meets the following conditions The input signal is high level greater t...

Page 64: ...Signal Sources without Bias Resistors However for larger source impedances this connection leaves the differential signal path significantly off balance Noise that couples electrostatically onto the p...

Page 65: ...USB 6210 6211 6212 device as shown in Figure 4 18 This fully balanced configuration offers slightly better noise rejection but has the disadvantage of loading the source down with the series combinat...

Page 66: ...he source but small enough not to produce significant input offset voltage as a result of input bias current typically 100 k to 1 M In this case connect the negative input directly to AI GND If the so...

Page 67: ...Floating Signal Sources All of the bias resistor configurations discussed in the Using Differential Connections for Floating Signal Sources section apply to the non referenced single ended bias resis...

Page 68: ...figure the channels for referenced single ended or non referenced single ended input modes Refer to the Configuring AI Ground Reference Settings in Software section for more information about the DAQ...

Page 69: ...quires a separate ground reference point or return signal The signal leads travel through noisy environments Two analog input channels AI and AI are available Differential signal connections reduce no...

Page 70: ...mode noise in the signal and the ground potential difference between the signal source and the device ground Refer to the Using Non Referenced Single Ended Connections for Ground Referenced Signal So...

Page 71: ...d Referenced Signal Sources With this type of connection the NI PGIA rejects both the common mode noise in the signal and the ground potential difference between the signal source and the device groun...

Page 72: ...d reference to AI SENSE AI SENSE is internally connected to the negative input of the NI PGIA Therefore the ground point of the signal connects to the negative input of the NI PGIA Any potential diffe...

Page 73: ...module When connecting various sources to the USB 6215 6216 6218 you can use differential single ended or a combination of single ended and differential connections Note You must always connect AI GND...

Page 74: ...Using the referenced single ended measurement configuration allows the USB 6215 6216 6218 to take measurements on all AI channels when all channels share a common ground Figure 4 25 shows an reference...

Page 75: ...for a remote sense for the negative input of the instrumentation amplifier PGIA that is shared among all channels configured for non referenced single ended mode The behavior of this configuration is...

Page 76: ...B 621x devices Figure 5 1 USB 621x Analog Output Circuitry The main blocks featured in the USB 621x analog output circuitry are as follows DAC0 and DAC1 Digital to analog converters DACs convert digit...

Page 77: ...ches depending on the frequency and nature of the output signal Visit ni com support for more information about minimizing glitches Analog Output Data Generation Methods When performing an analog outp...

Page 78: ...continues until you stop the operation There are three methods of continuous generation that control what data is written These methods are regeneration FIFO regeneration and non regeneration modes Re...

Page 79: ...AO Pause Trigger Signal sections for more information about these triggering actions Connecting Analog Output Signals AO 0 1 are the voltage output signals for AO channels 0 and 1 AO GND is the ground...

Page 80: ...O Sample Clock Timebase Signal AO Start Trigger Signal Use the AO Start Trigger ao StartTrigger signal to initiate a waveform generation If you do not use triggers you can begin a generation with a so...

Page 81: ...e the generation of AO samples in a DAQ sequence That is when AO Pause Trigger is active no samples occur If the AO Sample Clock is derived from AO Sample Clock Timebase for example when you choose th...

Page 82: ...ger specify a source and a polarity The source can be any input PFI signal The source also can be one of several other internal signals on your USB 621x device Refer to Device Routing in MAX in the NI...

Page 83: ...ble internal counter divides down the AO Sample Clock Timebase signal Using an External Source Use any input PFI line as the source of AO Sample Clock Routing AO Sample Clock to an Output Terminal You...

Page 84: ...AO Sample Clock Timebase signal 20 MHz Timebase 100 kHz Timebase USB 6211 6215 Devices PFI 0 3 USB 6212 6216 Devices PFI 0 15 USB 6218 Devices PFI 0 3 PFI 8 11 AO Sample Clock Timebase is not availab...

Page 85: ...eneration Finite generation Continuous generation Waveform generation You can perform these generations through programmed I O or USB Signal Stream data transfer mechanisms Some of the applications al...

Page 86: ...se lines also can be used as PFI inputs USB 6210 6211 6215 6218 devices have up to eight static digital output lines P1 0 7 These lines also can be used as PFI output By default the digital output lin...

Page 87: ...DI lines and updates of DO lines are software timed I O Protection on USB 6210 6211 6215 6218 Devices Each DI DO and PFI signal is protected against overvoltage undervoltage and overcurrent conditions...

Page 88: ...de receiving TTL signals and sensing external device states such as the state of the switch shown in the figure Digital output applications include sending TTL signals and driving external devices suc...

Page 89: ...software refer to the NI DAQmx Help or the LabVIEW Help in version 8 0 or later Digital I O on USB 6212 6216 Devices USB 6212 6216 devices contain Up to 16 DIO signals P0 0 15 Each signal can be indi...

Page 90: ...gainst overvoltage undervoltage and overcurrent conditions as well as ESD events However you should avoid these fault conditions by following these guidelines If you configure a PFI or DIO line as an...

Page 91: ...ore information about setting power up states in NI DAQmx or MAX Increasing Current Drive on USB 6212 6216 Devices The total internal current limit for digital outputs and power drawn from the 5 V ter...

Page 92: ...Applications in Software on USB 6212 6216 Devices You can use the USB 6212 6216 device in the following digital I O applications Static digital input Static digital output Note For more information ab...

Page 93: ...nfigured as the following A static digital output A timing output signal from AI AO or counter timer functions Note USB 6212 6216 Devices PFI signals on USB 6212 6216 devices can be configured as inpu...

Page 94: ...ing PFI Terminals as Timing Input Signals Use PFI terminals to route external timing signals to many different USB 621x functions Each input PFI terminal can be routed to any of the following signals...

Page 95: ...HoldCompleteEvent AI Reference Trigger ai ReferenceTrigger AI Sample Clock ai SampleClock AI Start Trigger ai StartTrigger AO Sample Clock ao SampleClock AO Start Trigger ao StartTrigger Counter n So...

Page 96: ...rs You can enable a programmable debouncing filter on each PFI signal When the filters are enabled your device samples the input on each rising edge of a filter clock USB 621x devices use an onboard o...

Page 97: ...25 ns N 5 Figure 7 4 Filter Example Enabling filters introduces jitter on the input signal For the 125 ns and 6 425 s filter settings the jitter is up to 25 ns On the 2 56 ms setting the jitter is up...

Page 98: ...have a smaller operating range than the AI signals Treat the DAQ device as you would treat any static sensitive device Always properly ground yourself and the equipment when handling the DAQ device o...

Page 99: ...621x Counters Counter 0 Counter 0 Source Counter 0 Timebase Counter 0 Aux Counter 0 HW Arm Counter 0 A Counter 0 B Counter 0 Up_Down Counter 0 Z Counter 0 Gate Counter 0 Internal Output Counter 0 TC I...

Page 100: ...ng up or down The counter values can be read on demand or with a sample clock Single Point On Demand Edge Counting With single point on demand edge counting the counter counts the number of edges on t...

Page 101: ...sampled on each active edge of a sample clock A USB Signal Stream transfers the sampled values to host memory The count values returned are the cumulative counts since the counter armed event that is...

Page 102: ...th a known period to the Source input of the counter The counter counts the number of rising or falling edges on the Source signal while the pulse on the Gate signal is active You can calculate the pu...

Page 103: ...hile the Gate input remains active On each trailing edge of the Gate signal the counter stores the count in a hardware save register A USB Signal Stream transfers the stored values to host memory Figu...

Page 104: ...the counter The counter counts the number of rising or falling edges occurring on the Source input between the two active edges of the Gate signal You can calculate the period of the Gate input by mul...

Page 105: ...e middle of a period of the Gate input The counter does not store a measurement for this incomplete period Figure 8 8 shows an example of a buffered period measurement In this example a period is defi...

Page 106: ...od Measurement In semi period measurements the counter measures a semi period on its Gate input signal after the counter is armed A semi period is the time between any two consecutive edges on the Gat...

Page 107: ...value for this incomplete semi period Figure 8 9 shows an example of a buffered semi period measurement Figure 8 9 Buffered Semi Period Measurement Note that if you are using an external signal as the...

Page 108: ...good for low frequency signals You can route the signal to measure F1 to the Gate of a counter You can route a known timebase Ft to the Source of the counter The known timebase can be 80MHzTimebase F...

Page 109: ...n timebase can be 80MHzTimebase For signals that might be slower than 0 02 Hz use a slower known timebase You can configure the counter to make K 1 buffered period measurements Recall that the first p...

Page 110: ...can generate the pulse externally and connect it to a PFI terminal You only need to use one counter if you generate the pulse externally Route the signal to measure F1 to the Source of the counter Co...

Page 111: ...0 as shown in Figure 8 13 Assume this signal to measure has frequency F1 Configure Counter 0 to generate a single pulse that is the width of N periods of the source input signal Figure 8 13 Method 3 T...

Page 112: ...uency corresponds to 1 600 cycles of the 80 MHz Timebase Your measurement may return 1 600 1 cycles depending on the phase of the signal with respect to the timebase As your frequency becomes larger t...

Page 113: ...ces in methods of measuring frequency For information about connecting counter signals refer to the Default Counter Timer Pinouts section Position Measurement You can use the counters to perform posit...

Page 114: ...he type of encoding X1 X2 or X4 Figure 8 14 shows a quadrature cycle and the resulting increments and decrements for X1 encoding When channel A leads channel B the increment occurs on the rising edge...

Page 115: ...ffers with quadrature encoder designs You must refer to the documentation for your quadrature encoder to obtain timing of channel Z with respect to channels A and B You must then ensure that channel Z...

Page 116: ...lock Position Measurement With buffered position measurement position measurement using a sample clock the counter increments based on the encoding used after the counter is armed The value of the cou...

Page 117: ...ive edge occurs on the Aux input the counter counts the number of rising or falling edges on the Source The counter ignores additional edges on the Aux input The counter stops counting upon receiving...

Page 118: ...easurement Figure 8 20 Single Two Signal Edge Separation Measurement Buffered Two Signal Edge Separation Measurement Buffered and single two signal edge separation measurements are similar but buffere...

Page 119: ...ration Single Pulse Generation The counter can output a single pulse The pulse appears on the Counter n Internal Output signal of the counter You can specify a delay from when the counter is armed to...

Page 120: ...a delay from the Start Trigger to the beginning of the pulse You also can specify the pulse width The delay and pulse width are measured in terms of a number of active edges of the Source input After...

Page 121: ...tion For information about connecting counter signals refer to the Default Counter Timer Pinouts section Pulse Train Generation Continuous Pulse Train Generation This function generates a train of pul...

Page 122: ...er n Internal Output signal is equal to the frequency of the Source input divided by M N For information about connecting counter signals refer to the Default Counter Timer Pinouts section Finite Puls...

Page 123: ...r generates the Frequency Output signal The Frequency Output signal is the Frequency Output Timebase divided by a number you select from 1 to 16 The Frequency Output Timebase can be either the 20 MHz...

Page 124: ...ive edge on Gate the counter cumulatively increments the delay between the Gate and the pulse on the output by a specified amount Thus the delay between the Gate and the pulse produced successively in...

Page 125: ...uts section Counter Timing Signals USB 621x devices feature the following counter timing signals Counter n Source Signal Counter n Gate Signal Counter n Aux Signal Counter n A Signal Counter n B Signa...

Page 126: ...11 6215 Devices PFI 0 3 USB 6212 6216 Devices PFI 0 15 USB 6218 Devices PFI 0 3 PFI 8 11 In addition Counter 1 TC or Counter 1 Gate can be routed to Counter 0 Source Counter 0 TC or Counter 0 Gate can...

Page 127: ...AI Sample Clock ai SampleClock AI Convert Clock ai ConvertClock AO Sample Clock ao SampleClock In addition Counter 1 Internal Output or Counter 1 Source can be routed to Counter 0 Gate Counter 0 Inter...

Page 128: ...ent input selectors for each of the A B and Z inputs You can route any input PFI signal to each input Counter n Up_Down Signal Counter n Up_Down is another name for the Counter n B signal Counter n HW...

Page 129: ...e Counter n Internal Output signal changes in response to Counter n TC The two software selectable output options are pulse output on TC and toggle output on TC The output polarity is software selecta...

Page 130: ...nals in the NI DAQmx Help or the LabVIEW Help in version 8 0 or later for more information about how to connect your signals for common counter measurements and generations USB 621x default PFI lines...

Page 131: ...igger can be configured to begin a finite or continuous pulse generation Once a continuous generation has triggered the pulses continue to generate until you stop the operation in software For finite...

Page 132: ...iod to measure The counter begins counting rising edges of Source t2 The rising edge of Sample Clock indicates that the USB 621x device should store the result of the measurement of the current period...

Page 133: ...clock with a 40 MHz frequency Note NI DAQmx only supports filters on counter inputs The following is an example of low to high transitions of the input signal High to low transitions work similarly As...

Page 134: ...o and rolls over This counter can run faster than the larger counters which simply count the rollovers of this smaller counter Thus the prescaler acts as a frequency divider on the Source and puts out...

Page 135: ...uld store the number of times an external Source pulses between rising edges on the Gate signal Example Application That Works Correctly No Duplicate Counting Figure 8 33 shows an external buffered si...

Page 136: ...r does not write the correct data to the buffer Figure 8 34 Duplicate Count Example Example Application That Prevents Duplicate Count With duplicate count prevention the counter synchronizes both the...

Page 137: ...chronously to the Source signal With duplicate count prevention the counter value and Counter n Internal Output signals change synchronously to the 80 MHz Timebase Enabling Duplicate Count Prevention...

Page 138: ...d clock generation are referenced to an isolated ground as shown in Figure 9 1 Figure 9 1 USB 6215 6216 6218 Block Diagram The bus interface circuitry is referenced to a non isolated ground The follow...

Page 139: ...evices section of Chapter 6 Digital I O The Connecting PFI Input Signals section of Chapter 7 PFI Digital Isolation USB 6215 6216 6218 devices use digital isolators Unlike analog isolators digital iso...

Page 140: ...on parasitic resistances causing voltage spikes These voltage spikes are called common mode noise a noise source that travels in the ground and is therefore common to both the ground and any signal re...

Page 141: ...pacitor between the isolated board ground and earth ground The voltage rating of the capacitor must be larger than the voltage drop between the isolated ground and earth ground Non Isolated Systems A...

Page 142: ...User input through the PFI terminals Routes and generates the main clock signals for the USB 621x device 80 MHz Timebase The 80 MHz Timebase can be used as the Source input to the 32 bit general purpo...

Page 143: ...each measurement and acquisition block Analog input Analog output Counter 0 Counter 1 Data Transfer Methods The two primary ways to transfer data across the USB bus are as follows USB Signal Stream A...

Page 144: ...ni com Changing Data Transfer Methods USB 621x devices have four dedicated USB Signal Stream channels To change your data transfer mechanism between USB Signal Streams and programmed I O use the Data...

Page 145: ...ng sections The Analog Input Digital Triggering section of Chapter 4 Analog Input The Analog Output Digital Triggering section of Chapter 5 Analog Output The Counter Triggering section of Chapter 8 Co...

Page 146: ...ser Manual 12 2 ni com You also can program your USB 621x device to perform an action in response to a trigger from a digital source The action can affect the following Analog input acquisition Analog...

Page 147: ...s USB 6210 USB 6211 6215 USB 6212 6216 Screw Terminal USB 6212 6216 Mass Termination USB 6212 6216 BNC USB 6218 Screw Terminal USB 6218 BNC Refer to the NI USB 621x Specifications available on the NI...

Page 148: ...s section of Chapter 3 Connector and LED Information Figure A 1 USB 6210 Pinout 5 6 7 8 1 2 3 4 13 14 15 16 9 10 11 12 AI 1 AI 9 AI 2 AI 10 AI 3 AI 11 AI SENSE AI 4 AI 12 AI 5 AI 13 AI GND AI 6 AI 14...

Page 149: ...DAQmx Help or the LabVIEW Help in version 8 0 or later Table A 1 Default NI DAQmx Counter Timer Pins Counter Timer Signal Default Terminal Number Name CTR 0 SRC 1 PFI 0 CTR 0 GATE 2 PFI 1 CTR 0 AUX 1...

Page 150: ...nal Descriptions section of Chapter 3 Connector and LED Information Figure A 2 USB 6211 6215 Pinout 5 6 7 8 1 2 3 4 13 14 15 16 9 10 11 12 AI 1 AI 9 AI 2 AI 10 AI 3 AI 11 AI SENSE AI 4 AI 12 AI 5 AI 1...

Page 151: ...DAQmx Help or the LabVIEW Help in version 8 0 or later Table A 2 Default NI DAQmx Counter Timer Pins Counter Timer Signal Default Terminal Number Name CTR 0 SRC 1 PFI 0 CTR 0 GATE 2 PFI 1 CTR 0 AUX 1...

Page 152: ...I 5 AI 13 AI GND AI 6 AI 14 AI 7 AI 15 PFI 0 P1 0 PFI 1 P1 1 PFI 2 P1 2 PFI 3 P1 3 D GND PFI 4 P1 4 PFI 5 P1 5 PFI 6 P1 6 PFI 7 P1 7 5 V D GND AO 0 AO 1 AO GND AI 0 AI 8 5 6 7 8 1 2 3 4 13 14 15 16 9...

Page 153: ...p or the LabVIEW Help in version 8 0 or later Table A 3 Default NI DAQmx Counter Timer Pins Counter Timer Signal Default Terminal Number Name CTR 0 SRC 33 PFI 8 CTR 0 GATE 34 PFI 9 CTR 0 AUX 35 PFI 10...

Page 154: ...Mass Termination USB 6212 6216 Mass Termination Pinout Figure A 4 shows the pinout of the USB 6212 Mass Termination and USB 6216 Mass Termination For a detailed description of each signal refer to th...

Page 155: ...AI GND AI 3 AI 10 AI GND AI 1 AI 8 D GND PFI 8 P2 0 PFI 7 P1 7 PFI 13 P2 5 PFI 4 P1 4 PFI 3 P1 3 PFI 2 P1 2 D GND PFI 15 P2 7 D GND PFI 10 P2 2 PFI 11 P2 3 P0 3 P0 7 P0 2 D GND P0 5 P0 0 D GND AO GND...

Page 156: ...ompatibility EMC requirements this product must be operated with shielded cables and accessories If unshielded cables or accessories are used the EMC specifications are no longer guaranteed unless all...

Page 157: ...des BNC connectivity to all analog signals some digital signals and spring terminals for other digital signals BNC 2111 Provides BNC connectivity to 16 single ended analog input signals two analog out...

Page 158: ...ndividually shielded twisted pair of wires Analog outputs are also individually shielded R68 68 Highly flexible unshielded ribbon cable Custom Cabling and Connectivity The CA 1000 is a configurable en...

Page 159: ...13 NI USB 621x User Manual USB 6212 6216 BNC USB 6212 6216 BNC Pinout Figure A 5 shows the pinout of the USB 6212 BNC and USB 6216 BNC For a detailed description of each signal refer to the I O Connec...

Page 160: ...I USB 621x User Manual A 14 ni com Figure A 5 USB 6212 6216 BNC Top Panel and Pinout NI USB 6212 6216 AI x AI x GS 0 1 F 5 k AI GND FS USB 621x Device Floating Source AI x AI x GS 0 1 F 5 k AI GND FS...

Page 161: ...ced signal GS source Refer to the Connecting Analog Input Signals on USB 6210 6211 6212 Devices or Connecting Analog Input Signals on USB 6215 6216 6218 Devices section of Chapter 4 Analog Input for m...

Page 162: ...each BNC connector that you use for two single ended channels set the source type switch to the GS position This setting disconnects the built in ground reference resistor from the negative terminal...

Page 163: ...onnecting Analog Input Signals on USB 6210 6211 6212 Devices or Connecting Analog Input Signals on USB 6215 6216 6218 Devices section of Chapter 4 Analog Input For a detailed description of each signa...

Page 164: ...nal as shown in Figure A 11 Figure A 11 USER BNC Connection Figure A 12 shows an example of how to use the USER BNC To access the PFI 8 P2 0 signal from a BNC connect USER on the screw terminal block...

Page 165: ...P0 0 In PFI 1 P0 1 In PFI 2 P0 2 In PFI 3 P0 3 In D GND PFI 4 P1 0 Out PFI 5 P1 1 Out PFI 6 P1 2 Out PFI 7 P1 3 Out 5 V D GND AO 0 AO 1 AO GND AI 0 AI 8 5 6 7 8 1 2 3 4 13 14 15 16 9 10 11 12 21 22 23...

Page 166: ...he LabVIEW Help in version 8 0 or later Table A 6 Default NI DAQmx Counter Timer Pins Counter Timer Signal Default Terminal Number Name CTR 0 SRC 1 PFI 0 CTR 0 GATE 2 PFI 1 CTR 0 AUX 34 PFI 9 CTR 0 OU...

Page 167: ...orporation A 21 NI USB 621x User Manual USB 6218 BNC USB 6218 BNC Pinout Figure A 14 shows the pinout of the USB 6218 BNC For a detailed description of each signal refer to the I O Connector Signal De...

Page 168: ...on NI USB 621x User Manual A 22 ni com Figure A 14 USB 6218 BNC Top Panel and Pinout NI USB 6218 AI x AI x GS 0 1 F 5 k AI GND FS USB 621x Device Floating Source AI x AI x GS 0 1 F 5 k AI GND FS USB 6...

Page 169: ...gnal FS source or a ground referenced signal GS source Refer to the Connecting Analog Input Signals on USB 6215 6216 6218 Devices section of Chapter 4 Analog Input for more information To measure a fl...

Page 170: ...t circuitry on the USB 6218 BNC When the switch is set to the FS position AI x is grounded through a 0 1 F capacitor in parallel with a 5 k resistor Figure A 16 Analog Input Circuitry FS GS AI 0 AI x...

Page 171: ...he BNC connector labeled AI 0 provides access to single ended channels AI 0 and AI 8 the BNC connector labeled AI 1 provides access to single ended channels AI 1 and AI 9 and so on Up to 32 single end...

Page 172: ...A 19 USER BNC Connection Figure A 20 shows an example of how to use the USER BNC To access the PFI 9 P0 5 signal from a BNC connect USER on the screw terminal block to PFI 9 P0 5 with a wire Figure A...

Page 173: ...AI 0 To circumvent this problem use a voltage follower that has operational amplifiers op amps with unity gain for each high impedance source before connecting to a USB 621x device Otherwise you must...

Page 174: ...ound Referenced Signal Sources section of Chapter 4 Analog Input for more information How can I use the AI Sample Clock and AI Convert Clock signals on a USB 621x device to sample the AI channel s USB...

Page 175: ...ches on the output signal These glitches are normal when a DAC switches from one voltage to another it produces glitches due to released charges The largest glitches occur when the most significant bi...

Page 176: ...Service Program Membership This program entitles members to direct access to NI Applications Engineers via phone and email for one to one technical support as well as exclusive access to on demand tra...

Page 177: ...ct by visiting ni com certification Calibration Certificate If your product supports calibration you can obtain the calibration certificate for your product at ni com calibration If you searched ni co...

Page 178: ...al Glossary Symbol Prefix Value p pico 10 12 n nano 10 9 micro 10 6 m milli 10 3 k kilo 103 M mega 106 Symbols Percent Positive of or plus Negative of or minus Plus or minus Less than Greater than Les...

Page 179: ...er 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...

Page 180: ...d impedance applications buffer 1 Temporary storage for acquired or generated data 2 A memory device that stores intermediate data between two devices bus buses The group of electrical conductors that...

Page 181: ...c noise pick up that is common to both the positive and negative polarities of the input leads to the instrument front end Common mode rejection is only a relevant specification for systems having a b...

Page 182: ...d I O transfers the CPU in the PC reads data from the DAQ device whenever the CPU receives a software signal to acquire a single data point Interrupt based data transfers occur when the DAQ device sen...

Page 183: ...se values are represented by numbers digital trigger A TTL level signal having two discrete levels A high and a low level DIO Digital input output driver Software unique to the device or type of devic...

Page 184: ...ta can be stored on the FIFO ahead of time This again reduces the effect of latencies associated with getting the data from system memory to the DAQ device filter A physical device or digital algorith...

Page 185: ...SI unit for measurement of frequency One hertz Hz equals one cycle per second 2 The number of scans read or updates written per second I I O Input Output The transfer of data to from a computer syste...

Page 186: ...e PGIA is allowed to settle before the next channel is sampled The interchannel delay is regulated by AI Convert Clock interface Connection between one or more of the following hardware software and t...

Page 187: ...nt panel optional shields and so on A module contains everything required to occupy one or more slots in a mainframe SCXI and PXI devices are modules monotonicity A characteristic of a DAC in which th...

Page 188: ...rence or system ground Also called floating signal sources Some common example of non referenced signal sources are batteries transformers or thermocouples NRSE Non Referenced Single Ended mode All me...

Page 189: ...th the signals on the tracks offset by 90 from each other This makes it possible to detect the direction of the motion R range The maximum and minimum parameters between which a sensor instrument or d...

Page 190: ...and produces a corresponding electrical signal Primary characteristics of sensors are sensitivity frequency range and linearity signal conditioning 1 Electronic equipment that makes transducer or oth...

Page 191: ...e A synchronous process is therefore locked and no other processes can run during this time T task In NI DAQmx a collection of one or more channels timing and triggering and other properties that appl...

Page 192: ...Source clock period tsp Source pulse width TTL Transistor Transistor Logic A digital circuit composed of bipolar transistors wired in a certain manner A typical medium speed digital technology Nominal...

Page 193: ...er Manual G 16 ni com Vs Signal source voltage virtual channel See channel W waveform 1 The plot of the instantaneous amplitude of a signal as a function of time 2 Multiple voltage readings taken at a...

Page 194: ...ConvertClockTimebase 4 19 ai HoldCompleteEvent 4 19 ai PauseTrigger 4 22 ai ReferenceTrigger 4 21 ai SampleClock 4 14 ai SampleClockTimebase 4 15 ai StartTrigger 4 20 analog input 4 1 channels samplin...

Page 195: ...pleClock 5 8 ao StartTrigger 5 5 applications counter input 8 2 counter output 8 21 edge counting 8 2 applying rubber feet 1 6 arm start trigger 8 33 B BNC cables 2 4 connecting signals A 15 A 23 boar...

Page 196: ...B 6216 Mass Termination pinout A 8 USB 6216 Screw Terminal pinout A 6 USB 6218 BNC pinout A 21 USB 6218 Screw Terminal pinout A 19 USB 6259 BNC pinout A 13 A 21 considerations for field wiring 4 10 fo...

Page 197: ...6 device information A 1 pinouts 1 2 specifications 1 2 A 1 USB 6210 A 2 USB 6211 A 4 USB 6212 BNC A 13 USB 6212 Mass Termination A 8 USB 6212 Screw Terminal A 6 USB 6215 A 4 USB 6216 BNC A 13 USB 62...

Page 198: ...gle two signal 8 20 enabling duplicate count prevention in NI DAQmx 8 39 encoders quadrature 8 16 encoding X1 8 16 X2 8 16 X4 8 17 equivalent time sampling 8 26 examples NI resources C 1 exporting tim...

Page 199: ...nced single ended mode 4 35 when to use in differential mode 4 32 when to use in non referenced single ended mode 4 32 when to use in RSE mode 4 33 H hardware 1 1 2 1 hardware timed acquisitions 4 9 g...

Page 200: ...ders 8 18 measuring high frequency with two counters 8 12 large range of frequencies using two counters 8 13 low frequency with one counter 8 10 averaged 8 11 methods data transfer 11 1 minimizing gli...

Page 201: ...s pinouts counter default 8 32 device 1 2 USB 6210 A 2 USB 6211 A 4 USB 6212 BNC A 13 USB 6212 Mass Termination A 8 USB 6212 Screw Terminal A 6 USB 6215 A 4 USB 6216 BNC A 13 USB 6216 Mass Termination...

Page 202: ...ptions 3 1 labels for USB 621x Screw Terminal 1 3 sources floating 4 25 ground referenced 4 31 Signal Stream USB 11 1 signals AI Convert Clock 4 16 AI Convert Clock Timebase 4 19 AI Hold Complete Even...

Page 203: ...ic DIO USB 6210 6211 6215 6218 6 2 USB 6212 6216 6 5 using PFI terminals as 7 3 strain relief 1 4 support technical C 1 switching from a large to a small input range 4 6 synchronous counting mode 8 37...

Page 204: ...212 Screw Terminal A 6 analog input signals 4 23 default counter timer pins A 7 digital I O 6 4 pinout A 6 USB 6215 A 4 analog input signals 4 36 default counter timer pins A 5 digital I O 6 1 pinout...

Page 205: ...signal labels 1 3 signal wire management 1 5 specifications xviii stacking 1 6 USB cable strain relief 1 4 using low impedance sources 4 6 using PFI terminals as static digital I Os 7 3 as timing inp...

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