National Instruments NI-USB-621x User Manual

DAQ M Series

NI USB-621x User Manual

Bus-Powered M Series USB Devices

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March 2008 371931E-01

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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 ni.com/info and enter the info code feedback.

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Important Information

Warranty

The NI USB-6210, NI USB-6211, NI USB-6212, NI USB-6215, NI USB-6216, and NI USB-6218 are warranted against defects in materials and workmanship for a period of one year from the date of shipment, as evidenced by receipts or other documentation. National Instruments will, at its option, repair or replace equipment that proves to be defective during the warranty period. This warranty includes parts and labor.

The media on which you receive National Instruments software are warranted not to fail to execute programming instructions, due to defects in materials and workmanship, for a period of 90 days from date of shipment, as evidenced by receipts or other documentation. National Instruments will, at its option, repair or replace software media that do not execute programming instructions if National Instruments receives notice of such defects during the warranty period. National Instruments does not warrant that the operation of the software shall be uninterrupted or error free.

A Return Material Authorization (RMA) number must be obtained from the factory and clearly marked on the outside of the package before any equipment will be accepted for warranty work. National Instruments will pay the shipping costs of returning to the owner parts which are covered by warranty.

National Instruments believes that the information in this document is accurate. The document has been carefully reviewed for technical accuracy. In the event that technical or typographical errors exist, National Instruments reserves the right to make changes to subsequent editions of this document without prior notice to holders of this edition. The reader should consult National Instruments if errors are suspected. In no event shall National Instruments be liable for any damages arising out of or related to this document or the information contained in it.

EXCEPT AS SPECIFIED HEREIN, NATIONAL INSTRUMENTS MAKES NO WARRANTIES, EXPRESS OR IMPLIED, AND SPECIFICALLY DISCLAIMS ANY WARRANTY OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE. CUSTOMER’S RIGHT TO RECOVER DAMAGES CAUSED BY FAULT OR NEGLIGENCE ON THE PART OF NATIONAL

INSTRUMENTS SHALL BE LIMITED TO THE AMOUNT THERETOFORE PAID BY THE CUSTOMER. NATIONAL INSTRUMENTS WILL NOT BE LIABLE FOR DAMAGES RESULTING FROM LOSS OF DATA, PROFITS, USE OF PRODUCTS, OR INCIDENTAL OR CONSEQUENTIAL DAMAGES, EVEN IF ADVISED OF THE POSSIBILITY THEREOF. This limitation of

the liability of National Instruments will apply regardless of the form of action, whether in contract or tort, including negligence. Any action against National Instruments must be brought within one year after the cause of action accrues. National Instruments shall not be liable for any delay in performance due to causes beyond its reasonable control. The warranty provided herein does not cover damages, defects, malfunctions, or service failures caused by owner’s failure to follow the National Instruments installation, operation, or maintenance instructions; owner’s modification of the product; owner’s abuse, misuse, or negligent acts; and power failure or surges, fire, flood, accident, actions of third parties, or other events outside reasonable control.

Copyright

Under the copyright laws, this publication may not be reproduced or transmitted in any form, electronic or mechanical, 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 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.

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Patents

For patents covering National Instruments products, refer to the appropriate location: Help»Patents in your software, the patents.txt file on your CD, or ni.com/patents.

WARNING REGARDING USE OF NATIONAL INSTRUMENTS PRODUCTS

(1)NATIONAL INSTRUMENTS PRODUCTS ARE NOT DESIGNED WITH COMPONENTS AND TESTING FOR A LEVEL OF RELIABILITY SUITABLE FOR USE IN OR IN CONNECTION WITH SURGICAL IMPLANTS OR AS CRITICAL COMPONENTS IN ANY LIFE SUPPORT SYSTEMS WHOSE FAILURE TO PERFORM CAN REASONABLY BE EXPECTED TO CAUSE SIGNIFICANT INJURY TO A HUMAN.

(2)IN ANY APPLICATION, INCLUDING THE ABOVE, RELIABILITY OF OPERATION OF THE SOFTWARE PRODUCTS CAN BE IMPAIRED BY ADVERSE FACTORS, INCLUDING BUT NOT LIMITED TO FLUCTUATIONS IN ELECTRICAL POWER SUPPLY, COMPUTER HARDWARE MALFUNCTIONS, COMPUTER OPERATING SYSTEM SOFTWARE FITNESS, FITNESS OF COMPILERS AND DEVELOPMENT SOFTWARE USED TO DEVELOP AN APPLICATION, INSTALLATION ERRORS, SOFTWARE AND HARDWARE COMPATIBILITY PROBLEMS, MALFUNCTIONS OR FAILURES OF ELECTRONIC MONITORING OR CONTROL DEVICES, TRANSIENT FAILURES OF ELECTRONIC SYSTEMS (HARDWARE AND/OR SOFTWARE), UNANTICIPATED USES OR MISUSES, OR ERRORS ON THE PART OF THE USER OR APPLICATIONS DESIGNER (ADVERSE FACTORS SUCH AS THESE ARE HEREAFTER COLLECTIVELY TERMED “SYSTEM FAILURES”). ANY APPLICATION WHERE A SYSTEM FAILURE WOULD CREATE A RISK OF HARM TO PROPERTY OR PERSONS (INCLUDING THE RISK OF BODILY INJURY AND DEATH) SHOULD NOT BE RELIANT SOLELY UPON ONE FORM OF ELECTRONIC SYSTEM DUE TO THE RISK OF SYSTEM FAILURE. TO AVOID DAMAGE, INJURY, OR DEATH, THE USER OR APPLICATION DESIGNER MUST TAKE REASONABLY PRUDENT STEPS TO PROTECT AGAINST SYSTEM FAILURES, INCLUDING BUT NOT LIMITED TO BACK-UP OR SHUT DOWN MECHANISMS. BECAUSE EACH END-USER SYSTEM IS CUSTOMIZED AND DIFFERS FROM NATIONAL INSTRUMENTS' TESTING PLATFORMS AND BECAUSE A USER OR APPLICATION DESIGNER MAY USE NATIONAL INSTRUMENTS PRODUCTS IN COMBINATION WITH OTHER PRODUCTS IN A MANNER NOT EVALUATED OR CONTEMPLATED BY NATIONAL INSTRUMENTS, THE USER OR APPLICATION DESIGNER IS ULTIMATELY RESPONSIBLE FOR VERIFYING AND VALIDATING THE SUITABILITY OF NATIONAL INSTRUMENTS PRODUCTS WHENEVER NATIONAL INSTRUMENTS PRODUCTS ARE INCORPORATED IN A SYSTEM OR APPLICATION, INCLUDING, WITHOUT LIMITATION, THE APPROPRIATE DESIGN, PROCESS AND SAFETY LEVEL OF SUCH SYSTEM OR APPLICATION.

Compliance

Compliance with FCC/Canada Radio Frequency Interference Regulations

Determining FCC Class

The Federal Communications Commission (FCC) has rules to protect wireless communications from interference. The FCC places digital electronics into two classes. 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 electronics emit weak signals during normal operation that can affect radio, television, or other wireless products.

All Class A products display a simple warning statement of one paragraph in length regarding interference and undesired operation. The FCC rules have restrictions regarding the locations where FCC Class A products can be operated.

Consult the FCC Web site at www.fcc.gov for more information.

FCC/DOC Warnings

This equipment generates and uses radio frequency energy and, if not installed and used in strict accordance with the instructions in this manual and the CE marking Declaration of Conformity*, may cause interference to radio and television reception. Classification requirements are the same for the Federal Communications Commission (FCC) and the Canadian Department of Communications (DOC).

Changes or modifications not expressly approved by NI could void the user’s authority to operate the equipment under the FCC Rules.

Class A

Federal Communications Commission

This equipment has been tested and found to comply with the limits for a Class A digital device, pursuant to part 15 of the FCC Rules. These limits are designed to provide reasonable protection against harmful interference when the equipment is operated in a commercial environment. This equipment generates, uses, and can radiate radio frequency energy and, if not installed and used in accordance with the instruction manual, may cause harmful interference to radio communications. Operation of this equipment in a residential area is likely to cause harmful interference in which case the user is required to correct the interference at their own expense.

Canadian Department of Communications

This Class A digital apparatus meets all requirements of the Canadian Interference-Causing Equipment Regulations. Cet appareil numérique de la classe A respecte toutes les exigences du Règlement sur le matériel brouilleur du Canada.

Compliance with EU Directives

Users in the European Union (EU) should refer to the Declaration of Conformity (DoC) for information* pertaining to the CE marking. Refer to the Declaration of Conformity (DoC) for this product for any additional regulatory compliance information. To obtain the DoC for this product, visit ni.com/certification, search by model number or product line, and click the appropriate link in the Certification column.

*The CE marking Declaration of Conformity contains important supplementary information and instructions for the user or installer.

Contents

About This Manual

Conventions ...................................................................................................................	xiii
Related Documentation..................................................................................................	xiv

Chapter 1

Getting Started

Installing NI-DAQmx ....................................................................................................	1-1
Installing Other Software...............................................................................................	1-1
Installing the Hardware..................................................................................................	1-1
Device Pinouts ...............................................................................................................	1-1
Device Specifications ....................................................................................................	1-2
Applying Signal Labels to the USB-621x......................................................................	1-2
USB Cable Strain Relief ................................................................................................	1-3
Mounting the USB-621x................................................................................................	1-4
Desktop Use.....................................................................................................	1-4
DIN Rail Mounting..........................................................................................	1-4
Panel Mounting ...............................................................................................	1-5

Chapter 2

DAQ System Overview

DAQ Hardware ..............................................................................................................	2-1
DAQ-STC2......................................................................................................	2-2
Calibration Circuitry........................................................................................	2-2
Signal Conditioning .......................................................................................................	2-3
Sensors and Transducers .................................................................................	2-3
Cables and Accessories..................................................................................................	2-4
USB-621x Mass Termination Custom Cabling...............................................	2-4
Programming Devices in Software ................................................................................	2-5

Chapter 3

Connector and LED Information

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

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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 ........................................................................................	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 Signal .................................................................	4-15
AI Convert Clock Signal.................................................................................	4-16
Using an Internal Source ..................................................................	4-16
Using an External Source .................................................................	4-16
Routing AI Convert Clock to an Output Terminal ...........................	4-16
Using a Delay from Sample Clock to Convert Clock ......................	4-17
Other Timing Requirements .............................................................	4-17
AI Convert Clock Timebase Signal ................................................................	4-19
AI Hold Complete Event Signal .....................................................................	4-19
AI Start Trigger Signal....................................................................................	4-20
Using a Digital Source......................................................................	4-20
Routing AI Start Trigger to an Output Terminal ..............................	4-20
AI Reference Trigger Signal ...........................................................................	4-21
Using a Digital Source......................................................................	4-22
Routing AI Reference Trigger to an Output Terminal .....................	4-22
AI Pause Trigger Signal..................................................................................	4-22
Using a Digital Source......................................................................	4-22
Getting Started with AI Applications in Software ........................................................	4-22
Connecting Analog Input Signals on USB-6210/6211/6212 Devices ..........................	4-23
Connecting Floating Signal Sources ...............................................................	4-25
What Are Floating Signal Sources?..................................................	4-25
When to Use Differential Connections with Floating
Signal Sources ...............................................................................	4-25
When to Use Referenced Single-Ended (RSE) Connections
with Floating Signal Sources .........................................................	4-25
When to Use Non-Referenced Single-Ended (NRSE)
Connections with Floating Signal Sources ....................................	4-26
Using Differential Connections for Floating Signal Sources ...........	4-27

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Using Non-Referenced Single-Ended (NRSE) Connections
for Floating Signal Sources............................................................	4-30
Using Referenced Single-Ended (RSE) Connections for
Floating Signal Sources..................................................................	4-31
Connecting Ground-Referenced Signal Sources .............................................	4-31
What Are Ground-Referenced Signal Sources?................................	4-31
When to Use Differential Connections with Ground-Referenced
Signal Sources................................................................................	4-32
When to Use Non-Referenced Single-Ended (NRSE)
Connections with Ground-Referenced Signal Sources ..................	4-32
When to Use Referenced Single-Ended (RSE) Connections with
Ground-Referenced Signal Sources ...............................................	4-33
Using Differential Connections for Ground-Referenced
Signal Sources................................................................................	4-33
Using Non-Referenced Single-Ended (NRSE) Connections for
Ground-Referenced Signal Sources ...............................................	4-34
Connecting Analog Input Signals on USB-6215/6216/6218 Devices...........................	4-36
Taking Differential Measurements..................................................................	4-36
Taking Referenced Single-Ended (RSE) Measurements ................................	4-37
Taking Non-Referenced Single-Ended (NRSE) Measurements .....................	4-38
Chapter 5
Analog Output
AO Range ......................................................................................................................	5-2
Minimizing Glitches on the Output Signal ....................................................................	5-2
Analog Output Data Generation Methods .....................................................................	5-2
Analog Output Digital Triggering .................................................................................	5-3
Connecting Analog Output Signals ...............................................................................	5-4
Analog Output Timing Signals ......................................................................................	5-4
AO Start Trigger Signal...................................................................................	5-5
Using a Digital Source ......................................................................	5-5
Routing AO Start Trigger to an Output Terminal.............................	5-6
AO Pause Trigger Signal.................................................................................	5-6
Using a Digital Source ......................................................................	5-7
AO Sample Clock Signal.................................................................................	5-7
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

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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 ...........................................................	6-4
Digital I/O on USB-6212/6216 Devices........................................................................	6-4
Static DIO on USB-6212/6216 Devices .........................................................	6-5
I/O Protection on USB-6212/6216 Devices....................................................	6-5
Programmable Power-Up States on USB-6212/6216 Devices .......................	6-6
Increasing Current Drive on USB-6212/6216 Devices...................................	6-6
Connecting Digital I/O Signals on USB-6212/6216 Devices.........................	6-6
Getting Started with DIO Applications in Software on
USB-6212/6216 Devices..............................................................................	6-7

Chapter 7

PFI

Using PFI Terminals as Timing Input Signals ..............................................................	7-2
Exporting Timing Output Signals Using PFI Terminals...............................................	7-3
Using PFI Terminals as Static Digital I/Os ...................................................................	7-3
Connecting PFI Input Signals........................................................................................	7-4
PFI Filters ......................................................................................................................	7-4
I/O Protection ................................................................................................................	7-6
Programmable Power-Up States....................................................................................	7-6

Chapter 8

Counters

Counter Input Applications ...........................................................................................	8-2
Counting Edges ...............................................................................................	8-2
Single Point (On-Demand) Edge Counting ......................................	8-2
Buffered (Sample Clock) Edge Counting.........................................	8-3
Controlling the Direction of Counting..............................................	8-4
Pulse-Width Measurement..............................................................................	8-4
Single Pulse-Width Measurement ....................................................	8-4
Buffered Pulse-Width Measurement ................................................	8-5
Period Measurement .......................................................................................	8-6
Single Period Measurement..............................................................	8-6
Buffered Period Measurement..........................................................	8-7

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Semi-Period Measurement ..............................................................................	8-8
Single Semi-Period Measurement.....................................................	8-8
Buffered Semi-Period Measurement.................................................	8-8
Frequency Measurement .................................................................................	8-9
Choosing a Method for Measuring Frequency .................................	8-13
Position Measurement .....................................................................................	8-15
Measurements Using Quadrature Encoders......................................	8-15
Measurements Using Two Pulse Encoders.......................................	8-17
Two-Signal Edge-Separation Measurement....................................................	8-18
Single Two-Signal Edge-Separation Measurement ..........................	8-18
Buffered Two-Signal Edge-Separation Measurement ......................	8-19
Counter Output Applications .........................................................................................	8-20
Simple Pulse Generation .................................................................................	8-20
Single Pulse Generation ....................................................................	8-20
Single Pulse Generation with Start Trigger ......................................	8-20
Retriggerable Single Pulse Generation .............................................	8-21
Pulse Train Generation ....................................................................................	8-22
Continuous Pulse Train Generation ..................................................	8-22
Frequency Generation .....................................................................................	8-23
Using the Frequency Generator ........................................................	8-23
Frequency Division .........................................................................................	8-24
Pulse Generation for ETS................................................................................	8-24
Counter Timing Signals .................................................................................................	8-25
Counter n Source Signal..................................................................................	8-26
Routing a Signal to Counter n Source...............................................	8-26
Routing Counter n Source to an Output Terminal ............................	8-26
Counter n Gate Signal .....................................................................................	8-27
Routing a Signal to Counter n Gate ..................................................	8-27
Routing Counter n Gate to an Output Terminal................................	8-27
Counter n Aux Signal ......................................................................................	8-27
Routing a Signal to Counter n Aux...................................................	8-27
Counter n A, Counter n B, and Counter n Z Signals.......................................	8-28
Routing Signals to A, B, and Z Counter Inputs ................................	8-28
Counter n Up_Down Signal ............................................................................	8-28
Counter n HW Arm Signal ..............................................................................	8-28
Routing Signals to Counter n HW Arm Input...................................	8-29
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

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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......................	8-36
Enabling Duplicate Count Prevention in NI-DAQmx......................	8-37

Chapter 9

Isolation and Digital Isolators on USB-6215/6216/6218 Devices

Digital Isolation .............................................................................................................	9-2
Benefits of an Isolated DAQ Device .............................................................................	9-2
Reducing Common-Mode Noise...................................................................................	9-3
Creating an AC Return Path............................................................................	9-3
Isolated Systems ...............................................................................	9-4
Non-Isolated Systems .......................................................................	9-4

Chapter 10

Digital Routing and Clock Generation

80 MHz Timebase .........................................................................................................	10-1
20 MHz Timebase .........................................................................................................	10-1
100 kHz Timebase.........................................................................................................	10-1

Chapter 11

Bus Interface

USB Signal Stream........................................................................................................	11-1
Data Transfer Methods ..................................................................................................	11-1
Changing Data Transfer Methods ...................................................................	11-2

Chapter 12

Triggering

Triggering with a Digital Source...................................................................................

12-1

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		Contents
Appendix A
Device-Specific Information
USB-6210 ......................................................................................................................		A-2
USB-6211/6215 .............................................................................................................		A-4
USB-6212/6216 Screw Terminal...................................................................................		A-6
USB-6212/6216 Mass Termination ...............................................................................		A-8
USB-6218 ......................................................................................................................		A-13
Appendix B
Troubleshooting
Appendix C
Technical Support and Professional Services
Glossary
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

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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.
Conventions
	The following conventions are used in this manual:
<>	Angle brackets that contain numbers separated by an ellipsis represent
	a range of values associated with a bit or signal name—for example,
	AO <3..0>.
»	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 select Options
	from the last dialog box.
	This icon denotes a note, which alerts you to important information.
	This icon denotes a caution, which advises you of precautions to take to
	avoid injury, data loss, or a system crash. When this symbol is marked on a
	product, refer to the Read Me First: Safety and Radio-Frequency
	Interference for information about precautions to take.
bold	Bold text denotes items that you must select or click in the software, such
	as menu items and dialog box options. Bold text also denotes parameter
	names.
italic	Italic text denotes variables, emphasis, a cross-reference, or an introduction
	to a key concept. Italic text also denotes text that is a placeholder for a word
	or value that you must supply.
monospace	Text in this font denotes text or characters that you should enter from the
	keyboard, sections of code, programming examples, and syntax examples.
	This font is also used for the proper names of disk drives, paths, directories,
	programs, subprograms, subroutines, device names, functions, operations,
	variables, filenames, and extensions.

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About This Manual

Platform	Text in this font denotes a specific platform and indicates that the text
	following it applies only to that platform.

Related Documentation

Each application software package and driver includes information about writing applications for taking measurements and controlling measurement devices. The following references to documents assume you have NI-DAQ 8.7.1 or later, and where applicable, version 7.1 or later of the NI application software.

NI-DAQmx for Windows

The NI-DAQmx 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. 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. Select Start»All Programs»National Instruments»NI-DAQ»

NI-DAQ Readme.

The NI-DAQmx Help contains general information about measurement concepts, key NI-DAQmx concepts, and common applications that are applicable to all programming environments. Select Start»All Programs» National Instruments»NI-DAQ»NI-DAQmx Help.

NI-DAQmx Base (Linux/Mac OS X/LabVIEW PDA 8.x)

The NI-DAQmx Base Getting Started Guide describes how to install your NI-DAQmx Base software, your NI-DAQmx Base-supported DAQ device, and how to confirm that your device is operating properly. In Windows, select Start»All Programs»National Instruments»NI-DAQmx Base» Documentation»Getting Started Guide.

Getting Started with NI-DAQmx Base for Linux and Mac Users describes how to install your NI-DAQmx Base software, your NI-DAQmx Base-supported DAQ device, and how to confirm that your device is operating properly on your Mac/Linux machine.

The NI-DAQmx Base Readme lists which devices are supported by this version of NI-DAQmx Base. In Windows, select Start»All Programs» National Instruments»NI-DAQmx Base»DAQmx Base Readme.

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About This Manual

The NI-DAQmx Base VI Reference Help contains VI reference and general information about measurement concepts. In LabVIEW, select Help» 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.

Note All NI-DAQmx Base documentation for Linux is installed at /usr/local/ natinst/nidaqmxbase/documentation.

Note All NI-DAQmx Base documentation for Mac OS X is installed at /Applications/ National Instruments/NI-DAQmx Base/documentation.

Note USB-6212/6216 devices are not supported in NI-DAQmx Base.

LabVIEW

If you are a new user, use the Getting Started with LabVIEW manual to familiarize yourself with the LabVIEW graphical programming environment and the basic LabVIEW features you use to build data

acquisition and instrument control applications. Open the Getting Started with LabVIEW manual by selecting Start»All Programs»National Instruments»LabVIEW»LabVIEW Manuals or by navigating to the labview\manuals directory and opening LV_Getting_Started.pdf.

Use the LabVIEW Help, available by selecting Help»Search the LabVIEW Help in LabVIEW, to access information about LabVIEW programming concepts, step-by-step instructions for using LabVIEW, and reference information about LabVIEW VIs, functions, palettes, menus, and tools. Refer to the following locations on the Contents tab of the LabVIEW Help for information about NI-DAQmx:

•Getting Started»Getting Started with DAQ—Includes overview information and a tutorial to learn how to take an NI-DAQmx measurement in LabVIEW using the DAQ Assistant.

•VI and Function Reference»Measurement I/O VIs and Functions—Describes the LabVIEW NI-DAQmx VIs and properties.

•Taking Measurements—Contains the conceptual and how-to information you need to acquire and analyze measurement data in LabVIEW, including common measurements, measurement

fundamentals, NI-DAQmx key concepts, and device considerations.

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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™/CVI™, select Help»Contents, then select

Using LabWindows/CVI»Data Acquisition.

The NI-DAQmx Library book of the LabWindows/CVI Help contains

API overviews and function reference for NI-DAQmx. Select Library

Reference»NI-DAQmx Library in the LabWindows/CVI Help.

Measurement Studio

If you program your NI-DAQmx-supported device in Measurement Studio using Visual C++, Visual C#, or Visual Basic .NET, you can interactively create channels and tasks by launching the DAQ Assistant from MAX or from within Visual Studio .NET. You can generate the configuration code based on your task or channel in Measurement Studio. Refer to the DAQ Assistant Help for additional information about generating code. You also can create channels and tasks, and write your own applications in your ADE using the NI-DAQmx API.

For help with NI-DAQmx methods and properties, refer to the NI-DAQmx

.NET Class Library or the NI-DAQmx Visual C++ Class Library included in the NI Measurement Studio Help. For general help with programming in Measurement Studio, refer to the NI Measurement Studio Help, which is fully integrated with the Microsoft Visual Studio .NET help. To view this help file in Visual Studio. NET, select Measurement Studio»

NI Measurement Studio Help.

To create an application in Visual C++, Visual C#, or Visual Basic .NET, follow these general steps:

1.In Visual Studio .NET, select File»New»Project to launch the New Project dialog box.

2.Find the Measurement Studio folder for the language you want to create a program in.

3.Choose a project type. You add DAQ tasks as a part of this step.

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ANSI C without NI Application Software

The NI-DAQmx Help contains API overviews and general information about measurement concepts. 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.

.NET Languages without NI Application Software

With the Microsoft .NET Framework version 1.1 or later, you can use NI-DAQmx to create applications using Visual C# and Visual Basic .NET without Measurement Studio. You need Microsoft Visual Studio .NET 2003 or Microsoft Visual Studio 2005 for the API documentation to be installed.

The installed documentation contains the NI-DAQmx API overview, measurement tasks and concepts, and function reference. This help is fully integrated into the Visual Studio .NET documentation. To view the NI-DAQmx .NET documentation, go to Start»Programs»National Instruments»NI-DAQ»NI-DAQmx .NET Reference Help. Expand

NI Measurement Studio Help»NI Measurement Studio .NET Class Library»Reference to view the function reference. Expand

NI Measurement Studio Help»NI Measurement Studio .NET Class Library»Using the Measurement Studio .NET Class Libraries to view conceptual topics for using NI-DAQmx with Visual C# and Visual Basic

.NET.

To get to the same help topics from within Visual Studio, go to Help» Contents. Select Measurement Studio from the Filtered By drop-down list and follow the previous instructions.

Device Documentation and Specifications

The NI USB-621x Specifications contains all specifications for the

USB-6210, USB-6211, USB-6212, USB-6215, USB-6216, and USB-6218

M Series devices.

Documentation for supported devices and accessories, including PDF and help files describing device terminals, specifications, features, and operation are on the NI-DAQmx CD that includes Device Documentation.

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Insert the CD, open the Device 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 application with NI products, NI offers training courses. To enroll in a course or obtain a detailed course outline, refer to ni.com/training.

Technical Support on the Web

For additional support, refer to ni.com/support or zone.ni.com.

Note You can download these documents at ni.com/manuals.

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 www.adobe.com to download Acrobat Reader. Refer to the National Instruments Product Manuals Library at ni.com/manuals for updated documentation resources.

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1

Getting Started

NI USB-621x 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. If you have not already installed your device, refer to the NI-DAQmx for USB Devices Getting Started Guide.

Before installing your DAQ device, you must install the software you plan to use with the device.

Installing NI-DAQmx

The NI-DAQmx for USB Devices Getting Started Guide, 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 application.

Installing Other Software

If you are using other software, refer to the installation instructions that accompany your software.

Installing the Hardware

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, Device-Specific Information, for USB-621x device pinouts.

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Device Specifications

Refer to the NI USB-621x Specifications, available on the NI-DAQ Device Documentation Browser or from ni.com/manuals, for more detailed 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. You can choose 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 connector, and apply the label, as shown in Figure 1-1.

	P/N 19XXXX REVX
1	msi	6000
or
2
or
or		1
		or
		2
		or
		3
		or
		4

1	Terminal Number Label		3	Differential Signal Name Label
2	Single-Ended Signal Name Label		4	User-Defined Custom Label

Figure 1-1. USB-621x Signal Labels

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USB Cable Strain Relief

You can provide strain relief for the USB cable in the following ways:

•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.

•Zip Tie Method—Thread a zip tie through the zip tie bar on the underside of the USB-621x and tighten around the USB cable, as shown in Figure 1-2b.

3

3

4

2

1

5

or

	a		b
1	USB Cable Strain Relief Groove (Large)	4	Zip Tie
2	USB Cable Strain Relief Groove (Small)	5	Zip Tie Bar
3	USB Cable

Figure 1-2. USB Cable Strain Relief Options

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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.

For secure desktop use. adhere the supplied rubber non-skid feet to the underside of the device, as shown in Figure 1-3.

Note Do not apply the rubber feet if you are panel mounting the USB-621x or stacking the device on another USB-621x device.

Figure 1-3. Applying Rubber Feet to the USB-621x

DIN Rail Mounting

The DIN rail mounting kit (part number 779689-01, not included in your USB-621x kit) is an accessory you can use to mount the USB-621x family of products to a standard DIN rail.

Note Apply strain relief, as described in the USB Cable Strain Relief section, before mounting the USB-621x to a DIN rail.

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Panel Mounting

To mount the USB-621x to a board or panel, complete the following steps while referring to Figure 1-4.

Figure 1-4.

Mounting the USB-621x on a Panel

Note Do not apply the rubber feet to the USB-621x when panel mounting the 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 KnowledgeBase document, USB-621x Panel Mounting Template. Go to ni.com/info and enter the info code ex3x98 to locate the KnowledgeBase.

2.Using the template, mark the bottom point and top point on the panel.

(USB-621x Screw Terminal Devices) The points will be 171.45 mm (6.75 in.) from each other.

(USB-621x Mass Termination Devices) The points will be 182.56 mm (7.188 in.) from each other.

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3.Remove the USB cable from the connector on the USB-621x.

4.Screw a #8 or M4 screw into the bottom point on the panel.

5.Set the USB-621x on the screw by fitting it into the bottom screw notch on the underside of the USB-621x.

6.Screw a #8 or M4 screw through the USB-621x top screw hole into the panel.

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DAQ System Overview

Figure 2-1 shows a typical DAQ system, which includes the USB-621x device, programming software, and PC (DAQ systems involving the USB-621x Mass Termination device can also include signal conditioning devices and a cable for accessory connection). The following sections contain more information about the components of a typical DAQ system.

DAQ	DAQ	Personal Computer
Hardware	Software	or Laptop

Figure 2-1. Components of a Typical DAQ System

DAQ Hardware

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.

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				Isolation
		Analog Input		Barrier
				(USB-6215/
				6216/6218
		Analog Output		devices only)
	Connector		Digital
		Digital I/O	Routing	Digital	Bus	Bus
			and Clock	Isolators	Interface
			Generation
	I/O
		Counters
		PFI
				Figure 2-2. USB-621x Block Diagram

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:

•Flexible AI and AO sample and convert timing

•Many triggering modes

•Independent AI, AO, and CTR FIFOs

•Generation and routing of internal and external timing signals

•Two flexible 32-bit counter/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 analog inputs and outputs have calibration circuitry to correct gain and offset errors. You can calibrate the device to minimize AI and AO errors caused by time and temperature drift at run time. No external circuitry is necessary; an internal reference ensures high accuracy and stability over time and temperature changes.

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Factory-calibration constants are permanently stored in an onboard EEPROM and cannot be modified. When you self-calibrate the device, software stores new constants in a user-modifiable section of the EEPROM. To return a device to its initial factory calibration settings, software can copy the factory-calibration constants to the user-modifiable section

of the EEPROM. Refer to the NI-DAQmx Help or the LabVIEW Help in version 8.0 or later for more information about using calibration constants.

For a detailed calibration procedure for USB-621x devices, refer to the

B/E/M/S Series Calibration Procedure for NI-DAQmx by clicking

Manual Calibration Procedures on ni.com/calibration.

Signal Conditioning

Many sensors and transducers require signal conditioning before a measurement system can effectively and accurately acquire the signal. The front-end signal conditioning system can include functions such as signal amplification, attenuation, filtering, electrical isolation,

simultaneous sampling, and multiplexing. In addition, many transducers require excitation currents or voltages, bridge completion, linearization, or high amplification for proper and accurate operation. Therefore, most computer-based measurement systems include some form of signal conditioning in addition to plug-in data acquisition DAQ devices.

Sensors and Transducers

Sensors can generate electrical signals to measure physical phenomena, such as temperature, force, sound, or light. Some commonly used sensors are strain gauges, thermocouples, thermistors, angular encoders, linear encoders, and resistance temperature detectors (RTDs).

To measure signals from these various transducers, you must convert them into a form that a DAQ device can accept. For example, the output voltage of most thermocouples is very small and susceptible to noise. Therefore, you may need to amplify or filter the thermocouple output before digitizing it. The manipulation of signals to prepare them for digitizing is called signal conditioning.

For more information about sensors, refer to the following documents:

•For general information about sensors, visit ni.com/sensors.

•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.

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•If you are using other application software, refer to Common Sensors in the NI-DAQmx Help or the LabVIEW Help in version 8.0 or later.

Cables and Accessories

Cable and accessory options for USB-621x devices are as follows:

•Combicon Accessory for USB-621x Screw Terminal Devices (Optional)—Your USB-621x kit includes combicon connectors with screws and signal labels. The NI USB-621x Accessory Kit (part number 779807-01) contains four additional combicon connectors with screws, a screwdriver, and additional signal labels. You can use the combicon accessory to create custom connection solutions for USB-621x Screw Terminal devices.

•Cables and Accessories for USB-621x Mass Termination Devices—Refer to the USB-6212/6216 Mass Termination Cables and Accessories section of Appendix A, Device-Specific Information, for a list of cables and accessories for USB-621x Mass Termination devices.

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:

•For AI signals, use shielded, twisted-pair wires for each AI pair of differential inputs. Connect the shield for each signal pair to the ground reference at the source.

•Route the analog lines separately from the digital lines.

•When using a cable shield, use separate shields for the analog and digital sections of the cable. Failure to do so results in noise coupling into the analog signals from transient digital signals.

For more information about the connectors used for DAQ devices, refer to the KnowledgeBase document, Specifications and Manufacturers for Board Mating Connectors, by going to ni.com/info and entering the info code rdspmb.

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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 has an application programming interface (API), which is a library of VIs, functions, classes, attributes, and properties for creating applications for your device.

USB-621x devices use the NI-DAQmx driver. NI-DAQmx includes a collection of programming examples 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 application.

To locate LabVIEW and LabWindows/CVI examples, open the National

Instruments Example Finder.

•In LabVIEW, select Help»Find Examples.

•In LabWindows/CVI, select Help»NI Example Finder.

Measurement Studio, Visual Basic, and ANSI C examples are located in the following directories:

•NI-DAQmx examples for Measurement Studio-supported languages are in the following directories:

–MeasurementStudio\VCNET\Examples\NIDaq

–MeasurementStudio\DotNET\Examples\NIDaq

•NI-DAQmx examples for ANSI C are in the

NI-DAQ\Examples\DAQmx ANSI C Dev directory

For additional examples, refer to zone.ni.com.

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Connector and LED Information

The I/O Connector Signal Descriptions and +5 V Power sections contain information about NI USB-621x connectors. The PWR/ACT LED Indicator section contains information about the NI USB-621x PWR/ACT LED.

Refer to Appendix A, Device-Specific Information, for device I/O connector pinouts. Refer to the Applying Signal Labels to the USB-621x section of Chapter 1, Getting Started, for information about applying signal labels.

I/O Connector Signal Descriptions

Table 3-1 describes the signals found on the I/O connectors. Not all signals are available on all devices.

		Table 3-1.	I/O Connector Signals
Signal Name	Reference	Direction		Description
AI GND	—	—		Analog Input Ground—These terminals are the reference
				point for single-ended AI measurements in RSE mode and the
				bias current return point for DIFF measurements. All three
				ground references—AI GND, AO GND, and D GND—are
				connected on the device.
AI <0..31>	Varies	Input		Analog Input Channels 0 to 31—For single-ended
				measurements, each signal is an analog input voltage channel.
				In RSE mode, AI GND is the reference for these signals. In
				NRSE mode, the reference for each AI <0..31> signal is
				AI SENSE.
				For differential measurements, AI 0 and AI 8 are the positive
				and negative inputs of differential analog input channel 0.
				Similarly, the following signal pairs also form differential input
				channels:
				<AI 1, AI 9>, <AI 2, AI 10>, <AI 3, AI 11>, <AI 4, AI 12>,
				<AI 5, AI 13>, <AI 6, AI 14>, <AI 7, AI 15>, <AI 16, AI 24>,
				<AI 17, AI 25>, <AI 18, AI 26>, <AI 19, AI 27>,
				<AI 20, AI 28>, <AI 21, AI 29>, <AI 22, AI 30>,
				<AI 23, AI 31>
AI SENSE	—	Input		Analog Input Sense—In NRSE mode, the reference for each
				AI <0..31> signal is AI SENSE.

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Table 3-1. I/O Connector Signals (Continued)

Signal Name	Reference	Direction	Description
AO <0..1>	AO GND	Output	Analog Output Channels 0 to 1—These terminals supply the
			voltage output of AO channels 0 to 1.
AO GND	—	—	Analog Output Ground—AO GND is the reference for
			AO <0..1>. All three ground references—AI GND, AO GND,
			and D GND—are connected on the device.
D GND	—	—	Digital Ground—D GND supplies the reference for
			PFI <0..15>/P0/P1 and +5 V. All three ground
			references—AI GND, AO GND, and D GND—are connected
			on the device.
+5 V	D GND	Input or	+5 V Power—These terminals provide a +5 V power source or
		Output	can be used to externally power the digital outputs.
PFI <0..3>,	D GND	Input	(USB-6210/6211/6215/6218 Devices) Programmable
PFI <8..11>/P0.<0..7>			Function Interface or Static Digital Input
			Channels 0 to 7—Each PFI terminal can be used to supply an
			external source for AI, AO, or counter/timer inputs.
			You also can use these terminals as static digital input lines.
PFI <4..7>,	D GND	Output	(USB-6210/6211/6215/6218 Devices) Programmable
PFI <12..15>/P1.<0..7>			Function Interface or Static Digital Output
			Channels 0 to 7—You can route many different internal AI,
			AO, or counter/timer outputs to each PFI terminal.
			You also can use these terminals as static digital output lines.
P0.<0..15>	D GND	Input or	(USB-6212/6216 Devices) Port 0 Digital I/O
		Output	Channels 0 to 15—You can individually configure each signal
			as an input or output.
PFI <0..7>/P1.<0..7>,	D GND	Input or	(USB-6212/6216 Devices) Programmable Function Interface
PFI <8..15>/P2.<0..7>		Output	or Digital I/O Channels 0 to 15—Each of these terminals can
			be individually configured as a PFI terminal or a digital I/O
			terminal.
			As a PFI input, each terminal can be used to supply an external
			source for AI, AO, DI, and DO timing signals or counter/timer
			inputs.
			As a PFI output, you can route many different internal AI, AO,
			DI, or DO timing signals to each PFI terminal. You also can
			route the counter/timer outputs to each PFI terminal.
			As a Port 1 or Port 2 digital I/O signal, you can individually
			configure each signal as an input or output.
NC	—	—	No connect—Do not connect signals to these terminals.

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