National Instruments Data Acquisition Device NI USB-621x User Manual
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National Instruments Data Acquisition Device NI USB-621x User Manual

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March 2008
371931E-01

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  • Page 1 DAQ M Series NI USB-621x User Manual Bus-Powered M Series USB Devices NI USB-621x User Manual Français Deutsch ni.com/manuals March 2008 371931E-01...
  • Page 2 Thailand 662 278 6777, Turkey 90 212 279 3031, United Kingdom 44 (0) 1635 523545 For further support information, refer to the Technical Support and Professional Services appendix. To comment on National Instruments documentation, refer to the National Instruments Web site at and enter ni.com/info the info code feedback ©...

  • Page 3: Important Information

    Instruments Corporation. National Instruments respects the intellectual property of others, and we ask our users to do the same. NI software is protected by copyright and other intellectual property laws. Where NI software may be used to reproduce software or other materials belonging to others, you may use NI software only to reproduce materials that you may reproduce in accordance with the terms of any applicable license or other legal restriction.
  • Page 4 These classes are known as Class A (for use in industrial-commercial locations only) or Class B (for use in residential or commercial locations). All National Instruments (NI) products are FCC Class A products. Depending on where it is operated, this Class A product could be subject to restrictions in the FCC rules. (In Canada, the Department of Communications (DOC), of Industry Canada, regulates wireless interference in much the same way.) Digital...

  • Page 5: Table Of Contents

    I/O Connector Signal Descriptions ...3-1 +5 V Power ...3-3 +5 V Power as an Output ...3-3 +5 V Power as an Input ...3-3 USB Device Fuse Replacement ...3-3 PWR/ACT LED Indicator ...3-5 © National Instruments Corporation NI USB-621x User Manual...
  • Page 6 Contents Chapter 4 Analog Input Analog Input Range... 4-2 Analog Input Ground-Reference Settings ... 4-3 Configuring AI Ground-Reference Settings in Software... 4-5 Multichannel Scanning Considerations... 4-5 Analog Input Data Acquisition Methods... 4-8 Analog Input Digital Triggering... 4-10 Field Wiring Considerations... 4-10 Analog Input Timing Signals ...
  • Page 7 Using an Internal Source...5-7 Using an External Source...5-8 Routing AO Sample Clock to an Output Terminal...5-8 Other Timing Requirements...5-8 AO Sample Clock Timebase Signal ...5-8 Getting Started with AO Applications in Software ...5-9 © National Instruments Corporation Contents NI USB-621x User Manual...
  • Page 8 Contents Chapter 6 Digital I/O Digital I/O on USB-6210/6211/6215/6218 Devices ... 6-1 Static DIO on USB-6210/6211/6215/6218 Devices ... 6-2 I/O Protection on USB-6210/6211/6215/6218 Devices... 6-2 Increasing Current Drive on USB-6210/6211/6215/6218 Devices ... 6-3 Connecting 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 ...
  • Page 9 Counter n Internal Output and Counter n TC Signals ...8-29 Routing Counter n Internal Output to an Output Terminal...8-29 Frequency Output Signal...8-29 Routing Frequency Output to a Terminal ...8-29 Default Counter/Timer Pinouts...8-30 Counter Triggering ...8-31 © National Instruments Corporation Contents NI USB-621x User Manual...
  • Page 10 Contents Other Counter Features... 8-32 Sample Clock ... 8-32 Cascading Counters... 8-33 Counter Filters... 8-33 Prescaling ... 8-34 Duplicate Count Prevention ... 8-35 Example Application That Works Correctly (No Duplicate Counting) ... 8-35 Example Application That Works Incorrectly (Duplicate Counting) ... 8-36 Example Application That Prevents Duplicate Count...
  • Page 11 Index Device Pinouts Figure A-1. USB-6210 Pinout ...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-6218 Pinout ...A-13 © National Instruments Corporation Contents NI USB-621x User Manual...

  • Page 12: About This Manual

    About This Manual The NI USB-621x User Manual contains information about using the National Instruments USB-621x data acquisition (DAQ) devices with NI-DAQmx 8.7.1 and later. NI USB-6210, USB-6211, USB-6212, USB-6215, USB-6216, and USB-6218 devices feature up to 32 analog input (AI) channels, up to two analog output (AO) channels, two counters, and up to eight lines of digital input (DI) and up to eight lines of digital output (DO), or 32 bidirectional static DIO lines.

  • Page 13: Related Documentation

    NI-DAQmx for Windows software, your NI-DAQmx-supported DAQ device, and how to confirm that your device is operating properly. Select Start»All Programs»National Instruments» NI-DAQ»NI-DAQmx for USB Devices Getting Started. The NI-DAQ Readme lists which devices are supported by this version of NI-DAQ.
  • Page 14 NI-DAQmx Base VI Reference Help. The NI-DAQmx Base C Reference 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. All NI-DAQmx Base documentation for Linux is installed at...

  • Page 15: Measurement Studio

    About This Manual LabWindows/CVI The Data Acquisition book of the LabWindows/CVI Help contains 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 Assistant. In LabWindows Using LabWindows/CVI»Data Acquisition.

  • Page 16: Device Documentation And Specifications

    Select Start»All Programs»National Instruments»NI-DAQmx Help. The NI-DAQmx C Reference Help describes the NI-DAQmx Library functions, which you can use with National Instruments data acquisition devices to develop instrumentation, acquisition, and control applications. Select Start»All Programs»National Instruments»NI-DAQ» NI-DAQmx C Reference Help.

  • Page 17: Technical Support On The Web

    DAQ specifications and manuals are available as PDFs. You must have Adobe Acrobat Reader with Search and Accessibility 5.0.5 or later installed to view the PDFs. Refer to the Adobe Systems Incorporated Web site at National Instruments Product Manuals Library at updated documentation resources. NI USB-621x User Manual ni.com/training ni.com/support...

  • Page 18: Getting Started

    The NI-DAQmx for USB Devices Getting Started Guide contains non-software-specific information about how to install USB devices. Device Pinouts Refer to Appendix A, pinouts. © National Instruments Corporation , offers NI-DAQmx users step-by-step ni.com/manuals Device-Specific Information, for USB-621x device NI USB-621x User Manual...

  • Page 19: Device Specifications

    Chapter 1 Getting Started Device Specifications Refer to the NI USB-621x Specifications, available on the NI-DAQ Device Documentation Browser or from information about USB-621x devices. Applying Signal Labels to the USB-621x Your USB-621x kit includes labels for the combicon connectors on USB-621x Screw Terminal devices.

  • Page 20: Usb Cable Strain Relief

    USB Cable Strain Relief Groove (Large) USB Cable Strain Relief Groove (Small) USB Cable © National Instruments Corporation Cable Strain Relief Groove Method—Press the USB cable into one of the two grooves on the underside of the USB-621x. Choose the USB cable groove that matches your USB cable size, as shown in Figure 1-2a.

  • Page 21: Mounting The Usb-621X

    Chapter 1 Getting Started Mounting the USB-621x You can use the USB-621x on a desktop or mount it to a standard DIN rail or a panel. Desktop Use You can use the USB-621x on a desktop. The USB-621x has grooves on the underside that allow it to be stacked with other like-sized USB-621x devices.

  • Page 22: Panel Mounting

    Note Note Apply strain relief, as described in the mounting the USB-621x. © National Instruments Corporation Figure 1-4. Mounting the USB-621x on a Panel USB Cable Strain Relief Download and print the panel mounting template PDF attached in the KnowledgeBase document, USB-621x Panel Mounting Template.
  • Page 23 Chapter 1 Getting Started NI USB-621x User Manual Remove the USB cable from the connector on the USB-621x. Screw a #8 or M4 screw into the bottom point on the panel. Set the USB-621x on the screw by fitting it into the bottom screw notch on the underside of the USB-621x.

  • Page 24: Daq System Overview

    DAQ hardware digitizes signals, performs D/A conversions to generate analog output signals, and measures and controls digital I/O signals. Figure 2-2 features components common to all USB-621x devices. © National Instruments Corporation Hardware Software Figure 2-1. Components of a Typical DAQ System...

  • Page 25: Daq-Stc2

    Chapter 2 DAQ System Overview Analog Input Analog Output Digital I/O Counters DAQ-STC2 The DAQ-STC2 implements a high-performance digital engine for M Series data acquisition hardware. Some key features of this engine include the following: • • • • • •...

  • Page 26: Signal Conditioning

    For more information about sensors, refer to the following documents: • • © National Instruments Corporation For general information about sensors, visit If you are using LabVIEW, refer to the LabVIEW Help by selecting Help»Search the LabVIEW Help in LabVIEW and then navigate to the Taking Measurements book on the Contents tab.

  • Page 27: Cables And Accessories

    Chapter 2 DAQ System Overview • Cables and Accessories Cable and accessory options for USB-621x devices are as follows: • • USB-621x Mass Termination Custom Cabling NI offers cables and accessories for many applications. However, if you want to develop your own cable, adhere to the following guidelines for best results: •...

  • Page 28: Programming Devices In Software

    Programming Devices in Software National Instruments measurement devices are packaged with NI-DAQ driver software, an extensive library of functions and VIs you can call from your application software, such as LabVIEW or LabWindows/CVI, to program all the features of your NI measurement devices. Driver software...

  • Page 29: Connector And Led Information

    Signal Name Reference AI GND — AI <0..31> Varies AI SENSE — © National Instruments Corporation Device-Specific Information, for device I/O Applying Signal Labels to the USB-621x Getting Started, for information about applying signal Table 3-1. I/O Connector Signals Direction —...
  • Page 30 P0.<0..15> D GND PFI <0..7>/P1.<0..7>, D GND PFI <8..15>/P2.<0..7> — © National Instruments Corporation Table 3-1. I/O Connector Signals (Continued) Direction Output Analog Output Channels 0 to 1—These terminals supply the voltage output of AO channels 0 to 1. —...

  • Page 31: +5 V Power

    Chapter 3 Connector and LED Information +5 V Power The +5 V terminals on the I/O connector can be use as either an output or an input. Both terminals are internally connected on the USB-621x. +5 V Power as an Output Because the USB-621x devices are bus powered, there is a 50 mA limit on the total current that can be drawn from the +5 V terminals and the digital outputs.
  • Page 32 Unscrewing and reinstalling the thread-forming screws over time will produce a Note compromised connection between the device top and bottom. © National Instruments Corporation Replace the broken fuse in the socket. Figure 3-1 shows the fuse location. 0.75A,125V Fuse, Socketed Figure 3-1.

  • Page 33: Pwr/Act Led Indicator

    Chapter 3 Connector and LED Information PWR/ACT LED Indicator The PWR/ACT LED indicator indicates device status. Table 3-2 shows the behavior of the PWR/ACT LED. LED State Not lit Device not powered or device error. Refer to device is powered. On, not blinking Device error.

  • Page 34: Analog Input

    The main blocks featured in the USB-621x analog input circuitry are as follows: • • • • © National Instruments Corporation NI-PGIA Input Range Selection Figure 4-1. USB-621x Analog Input Circuitry I/O Connector—You can connect analog input signals to the USB-621x device through the I/O connector.

  • Page 35: Analog Input Range

    Chapter 4 Analog Input • • • Analog Input Range The input range affects the resolution of the USB-621x device for an AI channel. For example, a 16-bit ADC converts analog inputs into one of 65,536 (= 2 So, for an input range of –10 V to 10 V, the voltage of each code of a 16-bit ADC is: USB-621x devices use a calibration method that requires some codes (typically about 5% of the codes) to lie outside of the specified range.

  • Page 36: Analog Input Ground-Reference Settings

    NI-PGIA. The NI-PGIA is a differential amplifier. That is, the NI-PGIA amplifies (or attenuates) the difference in voltage between its two inputs. The NI-PGIA drives the ADC © National Instruments Corporation Input Range Differential mode—In DIFF mode, USB-621x devices measure the difference in voltage between two AI signals.
  • Page 37 Chapter 4 Analog Input with this amplified voltage. The amount of amplification (the gain) is determined by the analog input range, as shown in Figure 4-2. Table 4-1 shows how signals are routed to the NI-PGIA. AI Ground-Reference Settings NRSE DIFF For differential measurements, AI 0 and AI 8 are the positive and negative inputs of differential analog input channel 0.

  • Page 38: Configuring Ai Ground-Reference Settings In Software

    USB-621x devices are designed to have fast settling times. However, several factors can increase the settling time which decreases the accuracy © National Instruments Corporation of the NI-DAQmx API. You must use a new VI for Figure 4-3. Enabling Multimode Scanning in LabVIEW...
  • Page 39 The capacitance of the cable also can increase the settling time. National Instruments recommends using individually shielded, twisted-pair wires that are 2 m or less to connect AI signals to the device. Refer to the...
  • Page 40 © National Instruments Corporation approximately 4 V step from 4 V to 1 mV is 1,000% of the new full-scale range. For a 16-bit device to settle within 0.0015% (15 ppm or 1 LSB) of the ±200 mV full-scale range on channel 1, the input circuitry must settle to within 0.000031% (0.31 ppm or...

  • Page 41: Analog Input Data Acquisition Methods

    Chapter 4 Analog Input • Analog Input Data Acquisition Methods When performing analog input measurements, you either can perform software-timed or hardware-timed acquisitions: • NI USB-621x User Manual Avoid Scanning Faster Than Necessary—Designing your system to scan at slower speeds gives the NI-PGIA more time to settle to a more accurate level.
  • Page 42 • © National Instruments Corporation Hardware-Timed Acquisitions—With hardware-timed acquisitions, a digital hardware signal, AI Sample Clock, controls the rate of the acquisition. This signal can be generated internally on your device or provided externally. Hardware-timed acquisitions have several advantages over software-timed acquisitions: –...

  • Page 43: Analog Input Digital Triggering

    Chapter 4 Analog Input Analog Input Digital Triggering Analog input supports three different triggering actions: • • • Refer to the AI Pause Trigger Signal A digital trigger can initiate these actions. All USB-621x devices support digital triggering. USB-621x devices do not support analog triggering. Field Wiring Considerations Environmental noise can seriously affect the measurement accuracy of the device if you do not take proper care when running signal wires between...

  • Page 44: Analog Input Timing Signals

    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 the sample period, which is determined by the following equation: © National Instruments Corporation Analog Comparison Event Ctr n Internal Output AI Sample...
  • Page 45 Chapter 4 Analog Input AI Convert Clock controls the Convert Period, which is determined by the following equation: The sampling rate is the fastest you can acquire data on the device and still achieve Note accurate results. For example, if a USB-621x device has a sampling rate of 250 kS/s, this sampling rate is aggregate—one channel at 250 kS/s or two channels at 125 kS/s per channel illustrates the relationship.
  • Page 46 • • • • • • • • © National Instruments Corporation AI Start Trigger AI Sample Clock AI Convert Clock Scan Counter Figure 4-7. Pretriggered Data Acquisition Example AI Sample Clock Signal AI Sample Clock Timebase Signal AI Convert Clock Signal...

  • Page 47: Ai Sample Clock Signal

    Chapter 4 Analog Input AI Sample Clock Signal Use the AI Sample Clock (ai/SampleClock) signal to initiate a set of measurements. Your USB-621x device samples the AI signals of every channel in the task once for every AI Sample Clock. A measurement acquisition consists of one or more samples.

  • Page 48: Ai Sample Clock Timebase Signal

    AI Sample Clock Timebase is divided down to provide one of the possible sources for AI Sample Clock. You can configure the polarity selection for AI Sample Clock Timebase as either rising or falling edge. © National Instruments Corporation AI Convert Clock Signal section for more information about the...

  • Page 49: Ai Convert Clock Signal

    Chapter 4 Analog Input AI Convert Clock Signal Use the AI Convert Clock (ai/ConvertClock) signal to initiate a single A/D conversion on a single channel. A sample (controlled by the AI Sample Clock) consists of one or more conversions. You can specify either an internal or external signal as the source of AI Convert Clock.

  • Page 50: Using A Delay From Sample Clock To Convert Clock

    AI Sample Clock. Figures 4-10, 4-11, 4-12, and 4-13 show timing sequences for a four-channel acquisition (using AI channels 0, 1, 2, and 3) and demonstrate proper and improper sequencing of AI Sample Clock and AI Convert Clock. © National Instruments Corporation Delay Convert From...
  • Page 51 Chapter 4 Analog Input Channel Measured Channel Measured AI Sample Clock AI Convert Clock Channel Measured NI USB-621x User Manual AI Sample Clock AI Convert Clock 1 2 3 Sample #1 Figure 4-10. AI Sample Clock Too Fast For AI Convert Clock; AI Sample Clock Pulses Are Gated Off AI Sample Clock AI Convert Clock...

  • Page 52: Ai Convert Clock Timebase Signal

    The AI Hold Complete Event (ai/HoldCompleteEvent) signal generates a pulse after each A/D conversion begins. You can route AI Hold Complete Event out to any output PFI terminal. © National Instruments Corporation AI Sample Clock AI Convert Clock 1 2 3 Sample #1 Figure 4-13.

  • Page 53: Ai Start Trigger Signal

    Chapter 4 Analog Input The polarity of AI Hold Complete Event is software-selectable, but is typically configured so that a low-to-high leading edge can clock external AI multiplexers indicating when the input signal has been sampled and can be removed. AI Start Trigger Signal Use the AI Start Trigger (ai/StartTrigger) signal to begin a measurement acquisition.

  • Page 54: Ai Reference Trigger Signal

    When the reference trigger occurs, the DAQ device continues to write samples to the buffer until the buffer contains the number of posttrigger samples desired. Figure 4-15 shows the final buffer. © National Instruments Corporation and enter the info code Reference Trigger...

  • Page 55: Using A Digital Source

    Chapter 4 Analog Input Using a Digital Source To use AI Reference Trigger with a digital source, specify a source and an edge. The source can be any input PFI signal. The source also can be one of several internal signals on your DAQ device. Refer to Device Routing in MAX in the NI-DAQmx Help or the LabVIEW Help in version 8.0 or later for more information.

  • Page 56: Connecting Analog Input Signals On Usb-6210/6211/6212 Devices

    NI-DAQmx Help or the LabVIEW Help in version 8.0 or later. Connecting Analog Input Signals on USB-6210/6211/6212 Devices Table 4-2 summarizes the recommended input configuration for both types of signal sources on USB-6210/6211/6212 devices. © National Instruments Corporation 4-23 Chapter 4 Analog Input NI USB-621x User Manual...

  • Page 57: Floating Signal Sources

    Chapter 4 Analog Input Table 4-2. USB-6210/6211/6212 Analog Input Configuration AI Ground-Reference Setting Differential (DIFF) Non-Referenced Single-Ended (NRSE) Referenced Single-Ended (RSE) Refer to the Analog Input Ground-Reference Settings software considerations. † Refer to the Connecting Ground-Referenced Signal Sources NI USB-621x User Manual Floating Signal Sources (Not Connected to Building Ground)

  • Page 58: Connecting Floating Signal Sources

    • • • © National Instruments Corporation The input signal is low level (less than 1 V). The leads connecting the signal to the device are greater than 3 m (10 ft). The input signal requires a separate ground-reference point or return signal.

  • Page 59: When To Use Non-Referenced Single-Ended (Nrse) Connections With Floating Signal Sources

    Chapter 4 Analog Input DIFF input connections are recommended for greater signal integrity for any input signal that does not meet the preceding conditions. In the single-ended modes, more electrostatic and magnetic noise couples into the signal connections than in DIFF configurations. The coupling is the result of differences in the signal path.

  • Page 60: Using Differential Connections For Floating Signal Sources

    This configuration does not load down the source (other than the very high input impedance of the NI-PGIA). © National Instruments Corporation Floating Signal Source –...
  • Page 61 Chapter 4 Analog Input You can fully balance the signal path by connecting another resistor of the same value between the positive input and AI GND on the 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 combination (sum) of the two resistors.
  • Page 62 Figure 4-19. © National Instruments Corporation AI– Input Multiplexers AI SENSE...

  • Page 63: Using Non-Referenced Single-Ended (Nrse) Connections For Floating Signal Sources

    Chapter 4 Analog Input Using Non-Referenced Single-Ended (NRSE) Connections for Floating Signal Sources It is important to connect the negative lead of a floating signals source to AI GND (either directly or through a resistor). Otherwise the source may float out of the valid input range of the NI-PGIA and the DAQ device returns erroneous data.

  • Page 64: Using Referenced Single-Ended (Rse) Connections For Floating Signal Sources

    1 and 100 mV, but the difference can be much higher if power distribution circuits are improperly connected. If a grounded signal source is incorrectly measured, this © National Instruments Corporation Configuring AI Ground-Reference Settings in section for more information about the DAQ Assistant.

  • Page 65: When To Use Differential Connections With Ground-Referenced Signal Sources

    Chapter 4 Analog Input difference can appear as measurement error. Follow the connection instructions for grounded signal sources to eliminate this ground potential difference from the measured signal. When to Use Differential Connections with Ground-Referenced Signal Sources Use DIFF input connections for any channel that meets any of the following conditions: •...

  • Page 66: When To Use Referenced Single-Ended (Rse) Connections With Ground-Referenced Signal Sources

    Using Differential Connections for Ground-Referenced Signal Sources Figure 4-22 shows how to connect a ground-referenced signal source to the USB-6210/6211/6212 device configured in DIFF mode. © National Instruments Corporation 4-33 NI USB-621x User Manual...

  • Page 67: Using Non-Referenced Single-Ended (Nrse) Connections For Ground-Referenced Signal Sources

    Chapter 4 Analog Input Referenced Common- Noise and 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 ground, shown as V AI+ and AI– must both remain within ±11 V of AI GND. Using Non-Referenced Single-Ended (NRSE) Connections for Ground-Referenced Signal Sources Figure 4-23 shows how to connect ground-reference signal sources to the...
  • Page 68 Using the DAQ Assistant, you can configure the channels for RSE or NRSE input modes. Refer to the Software © National Instruments Corporation AI <0..15> or AI <16..n> Input Multiplexers –...

  • Page 69: Connecting Analog Input Signals On Usb-6215/6216/6218 Devices

    Chapter 4 Analog Input Connecting Analog Input Signals on USB-6215/6216/6218 Devices You can connect the USB-6215/6216/6218 directly to a variety of devices and other signal sources. Make sure the devices you connect to the USB-6215/6216/6218 are compatible with the input specifications of the module.

  • Page 70: Taking Referenced Single-Ended (Rse) Measurements

    10 V of AI GND. In an RSE connection configuration, each input channel is measured with respect to AI GND. © National Instruments Corporation , to be rejected during the measurement of V AI 1...

  • Page 71: Taking Non-Referenced Single-Ended (Nrse) Measurements

    Chapter 4 Analog Input Taking Non-Referenced Single-Ended (NRSE) Measurements To reach a compromise between RSE and differential measurements, you can use an NRSE measurement configuration. This configuration allows for a remote sense for the negative (–) input of the instrumentation amplifier (PGIA) that is shared among all channels configured for NRSE mode.

  • Page 72: Analog Output

    AO 0 AO 1 The main blocks featured in the USB-621x analog output circuitry are as follows: • • © National Instruments Corporation DAC0 AO FIFO DAC1 AO Sample Clock Figure 5-1. USB-621x Analog Output Circuitry DAC0 and DAC1—Digital-to-analog converters (DACs) convert digital codes to analog voltages.

  • Page 73: Ao Range

    Chapter 5 Analog Output • • AO Range The AO range is ±10 V for USB-621x devices. Minimizing Glitches on the Output Signal When you use a DAC to generate a waveform, you may observe glitches on the output signal. These glitches are normal; when a DAC switches from one voltage to another, it produces glitches due to released charges.

  • Page 74: Analog Output Digital Triggering

    Analog Output Digital Triggering Analog output supports two different triggering actions: • • © National Instruments Corporation – Hardware-timed acquisitions can use hardware triggering. Hardware-timed operations are buffered. During hardware-timed AO generation, data is moved from a PC buffer to the onboard FIFO on the USB-621x device using USB Signal Streams before it is written to the DACs one sample at a time.

  • Page 75: Connecting Analog Output Signals

    Chapter 5 Analog Output A digital trigger can initiate these actions on USB-621x devices. Refer to 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 reference for AO <0..1>. Figure 5-2 shows how to make AO connections to the device.

  • Page 76: Ao Start Trigger Signal

    To use AO Start Trigger, specify a source and an edge. The source can be one of the following signals: • • • • • © National Instruments Corporation Ctr n Internal Output AO Sample Clock Timebase Programmable Clock Divider...

  • Page 77: Routing Ao Start Trigger To An Output Terminal

    Chapter 5 Analog Output The source also can be one of several internal signals on your USB-621x device. Refer to Device Routing in MAX in the NI-DAQmx Help or the LabVIEW Help in version 8.0 or later for more information. You also can specify whether the waveform generation begins on the rising edge or falling edge of AO Start Trigger.

  • Page 78: Using A Digital Source

    One of the following internal signals can drive AO Sample Clock: • • A programmable internal counter divides down the AO Sample Clock Timebase signal. © National Instruments Corporation Pause Trigger Sample Clock Figure 5-5. AO Pause Trigger with Other Signal Source AO Sample Clock Timebase (divided down)

  • Page 79: Using An External Source

    Chapter 5 Analog Output 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 can route AO Sample Clock (as an active low signal) out to any output PFI terminal.

  • Page 80: Getting Started With Ao Applications In Software

    Note For more information about programming analog output applications and triggers in software, refer to the NI-DAQmx Help or the LabVIEW Help in version 8.0 or later. © National Instruments Corporation PFI <0..15> (USB-6212/6216 Devices) (USB-6218 Devices) PFI <0..3>, PFI <8..11>...

  • Page 81: Digital I/O On Usb-6210/6211/6215/6218 Devices

    Figure 6-1 shows the circuitry of one DI line and one DO line. The following sections provide information about the various parts of the DIO circuit. © National Instruments Corporation Digital I/O on USB-6210/6211/6215/6218 Devices— USB-6210/6211/6215/6218 devices have up to eight lines of digital inputs (DI) and up to eight lines of digital output (DO).

  • Page 82: Static Dio On Usb-6210/6211/6215/6218 Devices

    Chapter 6 Digital I/O The DI terminals are named P0.<0..7> on the USB-6210/6211/6215/6218 device I/O connector. The DO terminals are named P1.<0..7> on the USB-6210/6211/6215/6218 device I/O connector. The voltage input and output levels and the current drive levels of the DIO lines are listed in the NI USB-621x Specifications.

  • Page 83: Increasing Current Drive On Usb-6210/6211/6215/6218 Devices

    Exceeding the maximum input voltage ratings, which are listed in the Caution NI USB-621x Specifications, can damage the DAQ device and the computer. NI is not liable for any damage resulting from such signal connections. © National Instruments Corporation Connector and LED P1.<0..3> TTL Signal P0.<0..3>...

  • Page 84: Getting Started With Dio Applications In Software On Usb-6210/6211/6215/6218 Devices

    Chapter 6 Digital I/O Getting Started with DIO Applications in Software on USB-6210/6211/6215/6218 Devices You can use the USB-6210/6211/6215/6218 device in the following digital I/O applications: • • For more information about programming digital I/O applications and triggers in Note software, refer to the NI-DAQmx Help or the LabVIEW Help in version 8.0 or later.

  • Page 85: Static Dio On Usb-6212/6216 Devices

    ESD events. However, you should avoid these fault conditions by following these guidelines: • • • • © National Instruments Corporation Static DO Buffer Digital Line Direction Control Static DI Figure 6-3. USB-6212/6216 Digital I/O Circuitry If you configure a PFI or DIO line as an output, do not connect it to any external signal source, ground signal, or power supply.

  • Page 86: Programmable Power-Up States On Usb-6212/6216 Devices

    Chapter 6 Digital I/O Programmable Power-Up States on USB-6212/6216 Devices At system startup and reset, the hardware sets all PFI and DIO lines to high-impedance inputs by default. The DAQ device does not drive the signal high or low. Each line has a weak pull-down resistor connected to it, as described in the NI USB-621x Specifications.

  • Page 87: Getting Started With Dio Applications In Software On Usb-6212/6216 Devices

    • • For more information about programming digital I/O applications and triggers in Note software, refer to the NI-DAQmx Help or the LabVIEW Help in version 8.0 or later. © National Instruments Corporation P1.<0..3> TTL Signal P0.<0..3> D GND USB-6212/6216 Device Figure 6-4.

  • Page 88: Pfi

    PFI line. PFI/DIO Pin I/O Protection Weak Pull-Down © National Instruments Corporation A static digital input A timing input signal for AI, AO, or counter/timer functions A static digital output A timing output signal from AI, AO, or counter/timer functions...

  • Page 89: Using Pfi Terminals As Timing Input Signals

    Chapter 7 Figure 7-2 shows the circuitry of an output PFI line. Isolation Barrier (USB-6215/ 6216/6218 devices only) Digital Timing Signals Isolators When a terminal is used as a timing input or output signal, it is called PFI x. When a terminal is used as a static digital input or output, it is called P0.x, P1.x, or P2.x.

  • Page 90: Exporting Timing Output Signals Using Pfi Terminals

    P1.x. On USB-6212/6216 devices, all PFI lines can be individually configured as static digital inputs or static digital outputs, called P0.x. © National Instruments Corporation AO Sample Clock Timebase (ao/SampleClockTimebase) AO Pause Trigger (ao/PauseTrigger) Counter input signals for either counter—Source, Gate, Aux,...

  • Page 91: Connecting Pfi Input Signals

    Chapter 7 Connecting PFI Input Signals All PFI input connections are referenced to D GND. Figure 7-3 shows this reference, and how to connect an external PFI 0 source and an external PFI 2 source to two PFI terminals. PFI Filters You can enable a programmable debouncing filter on each PFI signal.
  • Page 92 10.025 μs. Refer to the KnowledgeBase document, Digital Filtering with M Series, for more information about digital filters and counters. To access this KnowledgeBase, go to © National Instruments Corporation Table 7-1. Filters Pulse Width Needed to...

  • Page 93: I/O Protection

    Chapter 7 I/O Protection Each DI, DO, and PFI signal is protected against overvoltage, undervoltage, and overcurrent conditions as well as ESD events. However, you should avoid these fault conditions by following these guidelines: • • • • Programmable Power-Up States At system startup and reset, the hardware sets all output PFI and DO lines to high-impedance by default.

  • Page 94: Counters

    Input Selection Muxes Input Selection Muxes Input Selection Muxes © National Instruments Corporation Counter 0 Counter 0 Source (Counter 0 Timebase) Counter 0 Gate Counter 0 Internal Output Counter 0 Aux...

  • Page 95: Counter Input Applications

    Chapter 8 Counters The counters have seven input signals, although in most applications only a few inputs are used. For information about connecting counter signals, refer to the Counter/Timer Pinouts Counter Input Applications Counting Edges In edge counting applications, the counter counts edges on its Source after the counter is armed.

  • Page 96: Buffered (Sample Clock) Edge Counting

    Figure 8-4 shows an example of buffered edge counting. Notice that counting begins when the counter is armed, which occurs before the first active edge on Gate. © National Instruments Corporation Counter Armed Pause Trigger (Pause When Low)

  • Page 97: Controlling The Direction Of Counting

    Chapter 8 Counters Controlling the Direction of Counting In edge counting applications, the counter can count up or down. You can configure the counter to do the following: • • • For information about connecting counter signals, refer to the Counter/Timer Pinouts Pulse-Width Measurement In pulse-width measurements, the counter measures the width of a pulse on...

  • Page 98: Buffered Pulse-Width Measurement

    Note that if you are using an external signal as the Source, at least one Source pulse should occur between each active edge of the Gate signal. This condition ensures that correct values are returned by the counter. If this © National Instruments Corporation GATE SOURCE Counter Value Figure 8-5.

  • Page 99: Period Measurement

    Chapter 8 Counters condition is not met, consider using duplicate count prevention, described in the For information about connecting counter signals, refer to the Counter/Timer Pinouts Period Measurement In period measurements, the counter measures a period on its Gate input signal after the counter is armed.

  • Page 100: Buffered Period Measurement

    Note that if you are using an external signal as the Source, at least one Source pulse should occur between each active edge of the Gate signal. This condition ensures that correct values are returned by the counter. If this © National Instruments Corporation Counter Armed Figure 8-8. Buffered Period Measurement...

  • Page 101: Semi-Period Measurement

    Chapter 8 Counters condition is not met, the counter returns a zero. Refer to the Count Prevention For information about connecting counter signals, refer to the Counter/Timer Pinouts Semi-Period Measurement In semi-period measurements, the counter measures a semi-period on its Gate input signal after the counter is armed.

  • Page 102: Frequency Measurement

    Counter/Timer Pinouts Frequency Measurement You can use the counters to measure frequency in several different ways. You can choose one of the following methods depending on your application: • © National Instruments Corporation Counter Armed GATE SOURCE Counter Value Buffer Figure 8-9.
  • Page 103 Chapter 8 Counters • NI USB-621x User Manual You can configure the counter to measure one period of the gate signal. The frequency of F1 is the inverse of the period. Figure 8-10 illustrates method 1. Gate Source Single Period Measurement Figure 8-10.
  • Page 104 • © National Instruments Corporation Average the remaining K period measurements to determine the average period of F1. The frequency of F1 is the inverse of the average period. Figure 8-11 illustrates this method. Gate Source Buffered Period Measurement Average Period of F1 = Frequency of F1 = Figure 8-11.
  • Page 105 Chapter 8 Counters Pulse Gate Source Pulse-Width Measurement • NI USB-621x User Manual Figure 8-12 illustrates this method. Another option would be to measure the width of a known period instead of a known pulse. Width of Pulse (T) Pulse Width of Pulse Frequency of F1 =...

  • Page 106: Choosing A Method For Measuring Frequency

    The best method to measure frequency depends on several factors including the expected frequency of the signal to measure, the desired accuracy, how many counters are available, and the measurement duration. • © National Instruments Corporation Signal to SOURCE Measure (F1)
  • Page 107 Chapter 8 Counters Task Actual Frequency to Measure Timebase Frequency Actual Number of Timebase Periods Worst Case Measured Number of Timebase Periods Measured Frequency Error Error % • • • NI USB-621x User Manual 80 MHz Timebase. Your measurement may return 1600 ± 1 cycles depending on the phase of the signal with respect to the timebase.

  • Page 108: Position Measurement

    Measurements Using Quadrature Encoders The counters can perform measurements of quadrature encoders that use X1, X2, or X4 encoding. A quadrature encoder can have up to three channels—channels A, B, and Z. • © National Instruments Corporation Measures High Number of Measurements Returned Many section.
  • Page 109 Chapter 8 Counters • • Ch A Ch B Counter Value Channel Z Behavior Some quadrature encoders have a third channel, channel Z, which is also referred to as the index channel. A high level on channel Z causes the counter to be reloaded with a specified value in a specified phase of the quadrature cycle.

  • Page 110: Measurements Using Two Pulse Encoders

    The counter increments on each rising edge of channel A. The counter decrements on each rising edge of channel B, as shown in Figure 8-18. Counter Value 2 For information about connecting counter signals, refer to the Counter/Timer Pinouts © National Instruments Corporation Ch A Ch B Ch Z Max Timebase...

  • Page 111: Two-Signal Edge-Separation Measurement

    Chapter 8 Counters Two-Signal Edge-Separation Measurement Two-signal edge-separation measurement is similar to pulse-width measurement, except that there are two measurement signals—Aux and Gate. An active edge on the Aux input starts the counting and an active edge on the Gate input stops the counting. You must arm a counter to begin a two edge separation measurement.

  • Page 112: Buffered Two-Signal Edge-Separation Measurement

    A USB Signal Stream transfers the stored values to host memory. Figure 8-20 shows an example of a buffered two-signal edge-separation measurement. For information about connecting counter signals, refer to the Counter/Timer Pinouts © National Instruments Corporation Counter Armed GATE SOURCE Counter Value Figure 8-19.

  • Page 113: Counter Output Applications

    Chapter 8 Counters Counter Output Applications Simple Pulse Generation 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 the beginning of the pulse.

  • Page 114: Retriggerable Single Pulse Generation

    (using the rising edge of Source). GATE (Start Trigger) SOURCE Figure 8-23. Retriggerable Single Pulse Generation For information about connecting counter signals, refer to the Default Counter/Timer Pinouts section. © National Instruments Corporation 8-21 NI USB-621x User Manual...

  • Page 115: Pulse Train Generation

    Chapter 8 Counters Pulse Train Generation Continuous Pulse Train Generation This function generates a train of pulses with programmable frequency and duty cycle. The pulses appear on the Counter n Internal Output signal of the counter. You can specify a delay from when the counter is armed to the beginning of the pulse train.

  • Page 116: Frequency Generation

    Figure 8-26 shows the frequency generator output waveform when the divider is set to 5. Frequency Output Timebase FREQ OUT (Divisor = 5) © National Instruments Corporation Frequency Output Timebase Frequency Generator Divisor (1–16) Figure 8-25. Frequency Generator Block Diagram Figure 8-26.

  • Page 117: Frequency Division

    Chapter 8 Counters Frequency Output can be routed out to any output PFI terminal. All PFI terminals are set to high-impedance at startup. The FREQ OUT signal also can be routed to DO Sample Clock and DI Sample Clock. In software, program the frequency generator as you would program one of the counters for pulse train generation.

  • Page 118: Counter Timing Signals

    In this section, n refers to either Counter 0 or 1. For example, Counter n Source refers to two signals—Counter 0 Source (the source input to Counter 0) and Counter 1 Source (the source input to Counter 1). © National Instruments Corporation GATE D2 = D1 + ΔD Figure 8-27.

  • Page 119: Counter N Source Signal

    Chapter 8 Counters Counter n Source Signal The selected edge of the Counter n Source signal increments and decrements the counter value depending on the application the counter is performing. Table 8-3 lists how this terminal is used in various applications.

  • Page 120: Counter N Gate Signal

    Each counter has independent input selectors for the Counter n Aux signal. Any of the following signals can be routed to the Counter n Aux input: • • • © National Instruments Corporation PFI <0..3> (USB-6210/6211/6215 Devices) (USB-6212/6216 Devices) PFI <0..15>...

  • Page 121: Counter N A, Counter N B, And Counter N Z Signals

    Chapter 8 Counters • • In addition, Counter 1 Internal Output, Counter 1 Gate, Counter 1 Source, or Counter 0 Gate can be routed to Counter 0 Aux. Counter 0 Internal Output, Counter 0 Gate, Counter 0 Source, or Counter 1 Gate can be routed to Counter 1 Aux.

  • Page 122: Routing Signals To Counter N Hw Arm Input

    The Frequency Output (FREQ OUT) signal is the output of the frequency output generator. Routing Frequency Output to a Terminal You can route Frequency Output to any output PFI terminal. © National Instruments Corporation (USB-6210/6211/6215 Devices) PFI <0..3> PFI <0..15>...

  • Page 123: Default Counter/Timer Pinouts

    Chapter 8 Counters Default Counter/Timer Pinouts By default, NI-DAQmx routes the counter/timer inputs and outputs to the USB-6210/6211/6215 device PFI pins as shown in Table 8-4. Note You can find the default NI-DAQmx counter/timer pins for all USB-621x devices in the applicable section of Appendix A, You can use these defaults or select other sources and destinations for the counter/timer signals in NI-DAQmx.

  • Page 124: Counter Triggering

    • • • © National Instruments Corporation Arm Start Trigger—To begin any counter input or output function, you must first enable, or arm, the counter. Software can arm a counter or configure counters to be armed on a hardware signal. Software calls this hardware signal the Arm Start Trigger.

  • Page 125: Other Counter Features

    Chapter 8 Counters Other Counter Features Sample Clock When taking counter measurements, you can enable a sample clock. When you use a sample clock, measurements are saved after an active edge of the sample clock. Figure 8-28 shows an example of using a sample clock with a buffered period measurement.

  • Page 126: Cascading Counters

    The filter setting for each input can be configured independently. On power up, the filters are disabled. Figure 8-29 shows an example of a low to high transition on an input that has its filter set to 125 ns (N = 5). © National Instruments Corporation section. Table 8-5. Filters...

  • Page 127: Prescaling

    Chapter 8 Counters PFI Terminal Filter Clock (40 MHz) Filtered Input Enabling filters introduces jitter on the input signal. For the 125 ns and 6.425 μs filter settings, the jitter is up to 25 ns. On the 2.56 ms setting, the jitter is up to 10.025 μs.

  • Page 128: Duplicate Count Prevention

    The counter synchronizes or samples the Gate signal with the Source signal, so the counter does not detect a rising edge in Gate until the next Source pulse. In this example, the counter stores the values in the buffer on © National Instruments Corporation Gate Source Buffer Figure 8-31.

  • Page 129: Example Application That Works Incorrectly (Duplicate Counting)

    Chapter 8 Counters the first rising Source edge after the rising edge of Gate. The details of when exactly the counter synchronizes the Gate signal vary depending on the synchronization mode. Example Application That Works Incorrectly (Duplicate Counting) In Figure 8-32, after the first rising edge of Gate, no Source pulses occur, so the counter does not write the correct data to the buffer.

  • Page 130: Enabling Duplicate Count Prevention In Ni-Daqmx

    80 MHz Timebase. Enabling Duplicate Count Prevention in NI-DAQmx Duplicate count prevention is automatically used with USB-621x devices. Disabling duplicate count prevention is not supported. © National Instruments Corporation Counter detects rising Gate edge. Figure 8-33. Duplicate Count Prevention Example...

  • Page 131: Isolation And Digital Isolators On Usb-6215/6216/6218 Devices

    The bus interface circuitry is referenced to a non-isolated ground. The following table lists the ground symbols. USB-6216 devices have PFI/static DIO circuitry. © National Instruments Corporation , and digital routing and clock generation are referenced to an Isolation Barrier...

  • Page 132: Digital Isolation

    With isolation, engineers can safely measure a small signal in the presence of a large common-mode voltage signal. Some advantages of isolation are as follows: • • © National Instruments Corporation Chapter 9 Isolation and Digital Isolators on USB-6215/6216/6218 Devices Connecting Analog Input Signals on USB-6215/6216/6218 Devices...

  • Page 133: Reducing Common-Mode Noise

    Chapter 9 Isolation and Digital Isolators on USB-6215/6216/6218 Devices • Reducing Common-Mode Noise Isolated products require an isolated power supply to deliver power to the isolated side from the non-isolated side. Isolated power supplies work by switching voltages through a transformer with high-speed transistors. Switching voltages through the transformer cause charging and discharging of the parasitic capacitances and inductances in the switching power supplies that occur on every switch cycle, resulting in high-speed...

  • Page 134: Isolated Systems

    AC return path is only needed for high or source impedances. An AC return path can be created by connecting a capacitor between the device’s isolated ground and earth ground. © National Instruments Corporation NI USB-621x User Manual...

  • Page 135: Digital Routing And Clock Generation

    32-bit general-purpose counter/timers. The 100 kHz Timebase is generated by dividing down the 20 MHz Timebase by 200. © National Instruments Corporation Manages the flow of data between the bus interface and the acquisition/generation sub-systems (analog input, analog output, digital I/O, and the counters).

  • Page 136: Bus Interface

    Data Transfer Methods The two primary ways to transfer data across the USB bus are USB Signal Stream and programmed I/O: • • © National Instruments Corporation Analog input Analog output Counter 0 Counter 1 USB Signal Stream—A method to transfer data between the device and computer memory using USB bulk transfers without intervention of the microcontroller on the NI device.

  • Page 137: Changing Data Transfer Methods

    Chapter 11 Bus Interface 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 Transfer Mechanism property node function in NI-DAQmx. NI USB-621x User Manual Output Data Generation Methods Output, for more information.

  • Page 138: Triggering

    A rising edge is a transition from a low logic level to a high logic level. A falling edge is a high to low transition. Figure 12-1 shows a falling-edge trigger. © National Instruments Corporation Analog Input Digital Triggering Input...
  • Page 139 Chapter 12 Triggering 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: • • • NI USB-621x User Manual Analog input acquisition Analog output generation Counter behavior 12-2 ni.com...

  • Page 140: Device-Specific Information

    Refer to the NI USB-621x Specifications, available on the NI-DAQ Device Documentation Browser or from information about USB-621x devices. To obtain documentation for devices not listed here, refer to manuals © National Instruments Corporation USB-6210 USB-6211/6215 USB-6212/6216 Screw Terminal USB-6212/6216 Mass Termination USB-6218 ni.com/manuals...

  • Page 141: Figure

    Appendix A Device-Specific Information USB-6210 USB-6210 Pinout Figure A-1 shows the pinout of the USB-6210. For a detailed description of each signal, refer to the Descriptions NI USB-621x User Manual section of Chapter 3, Connector and LED PFI 0/P0.0 (In) PFI 1/P0.1 (In) PFI 2/P0.2 (In) PFI 3/P0.3 (In)
  • Page 142 Note For more information about default NI-DAQmx counter inputs, refer to Connecting Counter Signals in the NI-DAQmx Help or the LabVIEW Help in version 8.0 or later. © National Instruments Corporation Table A-1. Default NI-DAQmx Counter/Timer Pins Counter/Timer Signal CTR 0 SRC...

  • Page 143: Usb-6211/6215 Pinout

    Appendix A Device-Specific Information USB-6211/6215 USB-6211/6215 Pinout Figure A-2 shows the pinout of the USB-6211 and USB-6215. For a detailed description of each signal, refer to the Descriptions NI USB-621x User Manual section of Chapter 3, Connector and LED PFI 0/P0.0 (In) PFI 1/P0.1 (In) PFI 2/P0.2 (In) PFI 3/P0.3 (In)
  • Page 144 Note For more information about default NI-DAQmx counter inputs, refer to Connecting Counter Signals in the NI-DAQmx Help or the LabVIEW Help in version 8.0 or later. © National Instruments Corporation Table A-2. Default NI-DAQmx Counter/Timer Pins Counter/Timer Signal CTR 0 SRC...

  • Page 145: Usb-6212/6216 Screw Terminal Pinout

    Appendix A Device-Specific Information USB-6212/6216 Screw Terminal USB-6212/6216 Screw Terminal Pinout Figure A-3 shows the pinout of the USB-6212 Screw Terminal and USB-6216 Screw Terminal. For a detailed description of each signal, refer to the Descriptions NI USB-621x User Manual section of Chapter 3, Connector and LED PFI 0/P1.0...
  • Page 146 Note For more information about default NI-DAQmx counter inputs, refer to Connecting Counter Signals in the NI-DAQmx Help or the LabVIEW Help in version 8.0 or later. © National Instruments Corporation Table A-3. Default NI-DAQmx Counter/Timer Pins Counter/Timer Signal CTR 0 SRC...

  • Page 147: Usb-6212/6216 Mass Termination

    Appendix A Device-Specific Information USB-6212/6216 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 the Descriptions NI USB-621x User Manual section of Chapter 3, Connector and LED I/O Connector Signal...

  • Page 148: Usb-6212/6216 Mass Termination Pinout

    +5 V D GND PFI 5/P1.5 PFI 6/P1.6 D GND PFI 9/P2.1 PFI 12/P2.4 PFI 14/P2.6 NC = No Connect © National Instruments Corporation AI GND AI 9 AI 2 AI GND AI 11 AI SENSE AI 12 AI 5...
  • Page 149 Appendix A Device-Specific Information Note For more information about default NI-DAQmx counter inputs, refer to Connecting Counter Signals in the NI-DAQmx Help or the LabVIEW Help in version 8.0 or later. USB-6212/6216 Mass Termination Cables and Accessories This section describes some cable and accessory options for USB-6212/6216 Mass Termination devices.
  • Page 150 • • • • Screw Terminal Accessories National Instruments offers several styles of screw terminal connector blocks. Use an SH68-68-EPM shielded cable to connect a USB-6212/6216 Mass Termination device to a connector block, such as the following: • • •...
  • Page 151 Appendix A Device-Specific Information Custom Cabling and Connectivity The CA-1000 is a configurable enclosure that gives user-defined connectivity and flexibility through customized panelettes. Visit for more information about the CA-1000. Refer to the Chapter 2, cabling solutions. NI USB-621x User Manual USB-621x Mass Termination Custom Cabling DAQ System Overview, for more information about custom...

  • Page 152: Usb-6218

    USB-6218 USB-6218 Pinout Figure A-5 shows the pinout of the USB-6218. For a detailed description of each signal, refer to the Descriptions © National Instruments Corporation section of Chapter 3, Connector and LED PFI 0/P0.0 (In) PFI 1/P0.1 (In) PFI 2/P0.2 (In) PFI 3/P0.3 (In)
  • Page 153 Appendix A Device-Specific Information Note For more information about default NI-DAQmx counter inputs, refer to Connecting Counter Signals in the NI-DAQmx Help or the LabVIEW Help in version 8.0 or later. NI USB-621x User Manual Table A-5. Default NI-DAQmx Counter/Timer Pins Counter/Timer Signal CTR 0 SRC CTR 0 GATE...

  • Page 154: Troubleshooting

    Troubleshooting This section contains common questions about USB-621x devices. If your questions are not answered here, refer to the National Instruments KnowledgeBase at Analog Input I am seeing crosstalk or ghost voltages when sampling multiple channels. What does this mean?
  • Page 155 Appendix B Troubleshooting are various methods of achieving this reference while maintaining a high common-mode rejection ratio (CMRR). These methods are outlined in the Connecting Analog Input Signals on USB-6210/6211/6212 Devices Connecting Analog Input Signals on USB-6215/6216/6218 Devices sections of Chapter 4, AI GND is an AI common signal that routes directly to the ground connection point on the devices.
  • Page 156 DAC code changes. You can build a lowpass deglitching filter to remove some of these glitches, depending on the frequency and nature of the output signal. Visit ni.com/support © National Instruments Corporation Appendix B for more information about minimizing glitches. Troubleshooting...

  • Page 157: Technical Support And Professional Services

    Technical Support and Professional Services Visit the following sections of the National Instruments Web site at ni.com • • • © National Instruments Corporation for technical support and professional services: Support—Technical support resources at the following: – Self-Help Technical Resources—For answers and solutions,...
  • Page 158 Appendix C Technical Support and Professional Services • • If you searched your local office or NI corporate headquarters. Phone numbers for our worldwide offices are listed at the front of this manual. You also can visit the Worldwide Offices section of office Web sites, which provide up-to-date contact information, support phone numbers, email addresses, and current events.
  • Page 159 ± Plus or minus. < Less than. > Greater than. ≤ Less than or equal to. ≥ Greater than or equal to. Per. º Degree. Ω Ohm. © National Instruments Corporation Value –12 –9 –6 –3 NI USB-621x User Manual...
  • Page 160 Glossary Amperes—the unit of electric current. Analog-to-Digital. Most often used as A/D converter. Alternating current. accuracy A measure of the capability of an instrument or sensor to faithfully indicate the value of the measured signal. This term is not related to resolution; however, the accuracy level can never be better than the resolution of the instrument.
  • Page 161 When that relationship is known, the instrument may then be adjusted (calibrated) for best accuracy. cascading Process of extending the counting range of a counter chip by connecting to the next higher counter. © National Instruments Corporation Glossary NI USB-621x User Manual...
  • Page 162 Glossary European emissions control standard. channel Pin or wire lead to which you apply or from which you read the analog or digital signal. Analog signals can be single-ended or differential. For digital signals, you group channels to form ports. Ports usually consist of either four or eight digital channels.
  • Page 163 An electronic board that performs general analog or digital I/O functions on one or multiple channels, connected to a PC through a bus or I/O port, such as PCI, PXI, Ethernet, USB, or serial. © National Instruments Corporation Glossary NI USB-621x User Manual...
  • Page 164 Glossary DIFF Differential mode—An analog input mode consisting of two terminals, both of which are isolated from computer ground, whose difference is measured. differential input An input circuit that actively responds to the difference between two terminals, rather than the difference between one terminal and ground. Often associated with balanced input circuitry, but also may be used with an unbalanced source.
  • Page 165 The condition where a common mode voltage exists, or may exist, between earth ground and the instrument or circuit of interest. Neither the high, nor the low side of a circuit is at earth potential. © National Instruments Corporation Glossary NI USB-621x User Manual...
  • Page 166 Glossary floating signal sources Signal sources with voltage signals that are not connected to an absolute reference of system ground. Also called non-referenced signal sources. Some common examples of floating signal sources are batteries, transformers, and thermocouples. FREQ OUT Frequency Output signal. frequency The number of alternating signals that occur per unit time.
  • Page 167 2. A computer signal indicating that the CPU should suspend its current task to service a designated activity. Current, output high. Current, output low. See interrupt, interrupt request line. © National Instruments Corporation Glossary NI USB-621x User Manual...
  • Page 168 Glossary LabVIEW A graphical programming language. Light-Emitting Diode—A semiconductor light source. lowpass filter A filter that passes signals below a cutoff frequency while blocking signals above that frequency. Least Significant Bit. Meter. M Series An architecture for instrumentation-class, multichannel data acquisition devices based on the earlier E Series architecture with added new features.
  • Page 169 The period of a signal, most often measured from one zero crossing to the next zero crossing of the same slope. The period of a signal is the reciprocal of its frequency (in Hz). Period is designated by the symbol T. © National Instruments Corporation instrumentation amplifier.
  • Page 170 Glossary Programmable Function Interface. PGIA Programmable Gain Instrumentation Amplifier. physical channel See channel. posttriggering The technique used on a DAQ device to acquire a programmed number of samples after trigger conditions are met. power source An instrument that provides one or more sources of AC or DC power. Also known as power supply.
  • Page 171 When the arbitrary waveform generator goes through the staging list only once. © National Instruments Corporation G-13 Glossary NI USB-621x User Manual...
  • Page 172 Glossary single-buffered Describes a device that acquires a specified number of samples from one or more channels and returns the data when the acquisition is complete. single-ended input A circuit that responds to the voltage on one input terminal and ground. See also single-ended output A circuit whose output signal is present between one output terminal and...
  • Page 173 USB 2.0 retains compatibility with the original USB specification. Volts. Common-mode voltage. Ground loop voltage. Volts, input high. Volts, input low. Volts in. © National Instruments Corporation G-15 Glossary NI USB-621x User Manual...
  • Page 174 Glossary Measured voltage. Volts, output high. Volts, output low. Volts out. Signal source voltage. virtual channel See channel. waveform 1. The plot of the instantaneous amplitude of a signal as a function of time. 2. Multiple voltage readings taken at a specific sampling rate. NI USB-621x User Manual G-16 ni.com...
  • Page 175 AI Pause Trigger signal, 4-22 AI Reference Trigger signal, 4-21 AI Sample Clock signal, 4-14 AI Sample Clock Timebase signal, 4-15 AI Start Trigger signal, 4-20 © National Instruments Corporation ai/ConvertClock, 4-16 ai/ConvertClockTimebase, 4-19 ai/HoldCompleteEvent, 4-19 ai/PauseTrigger, 4-22 ai/ReferenceTrigger, 4-21...
  • Page 176 Index AI Reference Trigger, 4-21 AI Sample Clock, 4-14 AI Sample Clock Timebase, 4-15 AI Start Trigger, 4-20 analog output, 5-1 circuitry, 5-1 connecting signals, 5-4 data generation methods, 5-2 fundamentals, 5-1 getting started with applications in software, 5-9 glitches on the output signal, 5-2 range, 5-2 timing signals, 5-4 trigger signals, 5-3...
  • Page 177 Counter n Aux signal, 8-27 Counter n B signal, 8-28 Counter n Gate signal, 8-27 Counter n HW Arm signal, 8-28 © National Instruments Corporation Counter n Internal Output signal, 8-29 Counter n Source signal, 8-26 Counter n TC signal, 8-29...
  • Page 178 Index crosstalk when sampling multiple channels, B-1 custom cabling, 2-4 DACs, 5-1 hardware, 2-1 system, 2-1 DAQ-STC2, 2-2 data acquisition methods, 4-8 generation methods, 5-2 transfer methods, 11-1 changing, 11-2 programmed I/O, 11-1 USB Signal Stream, 11-1 Declaration of Conformity (NI resources), C-2 default counter terminals, 8-30 NI-DAQmx counter/timer pins, 8-30...
  • Page 179 4-25 description, 4-25 using in differential mode, 4-27 using in NRSE mode, 4-30 © National Instruments Corporation using in RSE mode, 4-31 when to use in differential mode, 4-25 when to use in NRSE mode, 4-26 when to use in RSE mode, 4-25...
  • Page 180 Index ground-referenced signal sources connecting, 4-31 description, 4-31 using in differential mode, 4-33 using in NRSE mode, 4-34 when to use in differential mode, 4-32 when to use in NRSE mode, 4-32 when to use in RSE mode, 4-33 hardware, 1-1, 2-1 hardware-timed acquisitions, 4-9 generations, 5-2...
  • Page 181 4-7 mounting DIN rail, 1-4 panel, 1-5 multichannel scanning considerations, 4-5 MUX, 4-1 National Instruments support and services, C-1 .NET languages documentation, xvii NI-DAQmx default counter terminals, 8-30 documentation, xiv device documentation browser, xvii enabling duplicate count prevention, 8-37...
  • Page 182 Index pins, default, 8-30 position measurement, 8-15 power, +5 V, 3-3 input, 3-3 output, 3-3 power-up states, 7-6 USB-6212/6216, 6-6 prescaling, 8-34 programmable function interface, 7-1 power-up states, 7-6 USB-6212/6216, 6-6 programmed I/O, 11-1 changing data transfer methods, 11-2 programming devices in software, 2-5 programming examples (NI resources), C-1 pulse encoders, 8-17...
  • Page 183 8-6 point edge counting, 8-2 pulse generation, 8-20 retriggerable, 8-21 with start trigger, 8-20 pulse-width measurement, 8-4 semi-period measurement, 8-8 © National Instruments Corporation two-signal edge-separation measurement, 8-18 single-ended connections for floating signal sources, 4-31 RSE configuration, 4-31 software...
  • Page 184 Index timing output signals, exporting using PFI terminals, 7-3 training, xviii training and certification (NI resources), C-1 transducers, 2-3 trigger, 12-1 arm start, 8-31 pause, 8-31 start, 8-31 triggering, 12-1 analog input, 4-10 counter, 8-31 with a digital source, 12-1 troubleshooting analog input, B-1 analog output, B-3...
  • Page 185 PFI terminals as static digital I/Os, 7-3 as timing input signals, 7-2 to export timing output signals, 7-3 using short high-quality cabling, 4-6 © National Instruments Corporation waveform generation signals, 5-4 Web resources, C-1 X1 encoding, 8-15 X2 encoding, 8-16...

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