National Instruments NI 6221, NI 6225, NI 6220, NI 6224, NI 6250, NI 6229 M, NI 6251, NI 6254, NI 6255, NI 6280, NI 6259 M, NI 6281, NI 6284, NI 6289 M User Manual
Specifications and Main Features
Frequently Asked Questions
User Manual
DAQ M Series
M Series User Manual
NI 622x, NI 625x, and NI 628x Devices
M Series User Manual
June 2007
371022H-01
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The M Series User Manual contains information about using the National
Instruments M Series data acquisition (DAQ) devices with NI-DAQ 8.6 and
later. M Series devices feature up to 80 analog input (AI) channels, and up
to four analog output (AO) channels, up to 48 lines of digital input/output
(DIO), and two counters.
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.
boldBold 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.
italicItalic 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.
monospaceText 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,
PlatformText 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 8.6 or later, and where applicable, version 7.0 or later of the
NI application software.
NI-DAQmx for Windows
The DAQ Getting Started Guide describes how to install your NI-DAQmx
for Windows software, how to install your NI-DAQmx-supported DAQ
device, and how to confirm that your device is operating properly. Select
Start»All Programs»National Instruments»NI-DAQ»DAQ Getting
Started Guide.
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 for Linux
The DAQ Getting Started Guide describes how to install your
NI-DAQmx-supported DAQ device and confirm that your device is
operating properly.
The NI-DAQ Readme for Linux lists supported devices and includes
software installation instructions, frequently asked questions, and known
issues.
The C Function Reference Help describes functions and attributes.
M Series User Manualxvini.com
The NI-DAQmx for Linux Configuration Guide provides configuration
instructions, templates, and instructions for using test panels.
Note All NI-DAQmx documentation for Linux is installed at
/usr/local/natinst/nidaqmx/docs.
Note USB-622x/625x devices are not supported in NI-DAQmx for Linux.
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.
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
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.
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.
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.
M Series User Manualxviiini.com
™
/CVI™, select Help»Contents, then select
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
2.Find the Measurement Studio folder for the language you want to
3.Choose a project type. You add DAQ tasks as a part of this step.
About This Manual
Project dialog box.
create a program in.
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-DAQ»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.
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 622x Specifications contains all specifications for the NI 6220,
NI 6221, NI 6224, NI 6225, and NI 6229 M Series devices.
The NI 625x Specifications contains all specifications for the NI 6250,
NI 6251, NI 6254, NI 6255, and NI 6259 M Series devices.
The NI 628x Specifications contains all specifications for the NI 6280,
NI 6281, NI 6284, and NI 6289 M Series devices.
NI-DAQmx includes the Device Document Browser, which contains online
documentation for supported DAQ and SCXI devices, such as documents
describing device pinouts, features, and operation. You can find, view,
and/or print the documents for each device using the Device Document
Browser at any time by inserting the CD. After installing the Device
Document Browser, device documents are accessible from Start»
All Programs»National Instruments»NI-DAQ»Browse Device
Documentation.
M Series User Manualxxni.com
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
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 some DAQ 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.
www.adobe.com to download Acrobat Reader. Refer to the
M Series devices feature up to 80 analog input (AI) channels, up to four
analog output (AO) channels, up to 48 lines of digital input/output (DIO),
and two counters. If you have not already installed your device, refer to the
DAQ Getting Started Guide. For specifications arranged by M Series
device family, refer to the specifications document for your device on
ni.com/manuals.
Before installing your DAQ device, you must install the software you plan
to use with the device.
Installing NI-DAQmx
The DAQ Getting Started Guide, which you can download at
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.
1
Installing Other Software
If you are using other software, refer to the installation instructions that
accompany your software.
Installing the Hardware
The DAQ Getting Started Guide contains non-software-specific
information about how to install PCI, PCI Express, PXI, PXI Express, and
USB devices, as well as accessories and cables.
Device Pinouts
Refer to Appendix A, Device-Specific Information, for M Series device
pinouts.
Refer to the specifications for your device, the NI 622x Specifications, the
NI 625x Specifications, or the NI 628x Specifications, available on the
NI-DAQ Device Document Browser or
detailed information about M Series devices.
ni.com/manuals, for more
Device Accessories and Cables
NI offers a variety of accessories and cables to use with your DAQ device.
Refer to Appendix A, Device-Specific Information, or
information.
ni.com for more
Applying the Signal Label to USB-622x/625x Screw
Terminal Devices
(USB-622x/625x Screw Terminal Devices) The supplied signal label can be
adhered to the inside cover of the USB-622x/625x Screw Terminal device
with supplied velcro strips as shown in Figure 1-1.
Figure 1-1. Applying the USB-622x/625x Screw Terminal Signal Label
M Series User Manual1-2ni.com
USB Cable Strain Relief
(USB-622x/625x Screw Terminal and USB-622x/625x Mass Termination Devices)
Use the supplied strain relief hardware to provide strain relief for your USB
cable. Adhere the cable tie mount to the rear panel of the USB-622x/625x
Screw Terminal or USB-622x/625x Mass Termination device, as shown in
Figure 1-2. Thread a zip tie through the cable tie mount and tighten around
the USB cable.
Chapter 1Getting Started
Figure 1-2. USB Cable Strain Relief on USB-622x/625x Screw Terminal and
(USB-622x/625x BNC Devices) Thread a zip tie through two of the strain relief
holes on the end cap to provide strain relief for your USB cable as shown
in Figure 1-3. The strain relief holes can also be used as cable management
for signal wires to/from the screw terminals and BNC connectors.
Figure 1-3. USB Cable Strain Relief on USB-622x/625x BNC Devices
M Series User Manual1-4ni.com
DAQ System Overview
r
Figure 2-1 shows a typical DAQ system, which includes sensors,
transducers, signal conditioning devices, cables that connect the various
devices to the accessories, the M Series device, programming software, and
PC. The following sections cover the components of a typical DAQ system.
2
Signal
Sensors and
Transducers
Conditioning
DAQ Hardware
Cables and
Accessories
Figure 2-1. Components of a Typical DAQ System
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 M Series devices.
The DAQ-STC2 and DAQ-6202 implement 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, DI, and DO FIFOs
•Generation and routing of RTSI signals for multi-device
synchronization
•Generation and routing of internal and external timing signals
•Two flexible 32-bit counter/timer modules with hardware gating
•Digital waveform acquisition and generation
•Static DIO signals
•True 5 V high current drive DO
•DI change detection
•PLL for clock synchronization
•Seamless interface to signal conditioning accessories
•PCI/PXI interface
•Independent scatter-gather DMA controllers for all acquisition and
generation functions
Digital
Routing
and Clock
Generation
RTSI
Figure 2-2. General M Series Block Diagram
Bus
Interface
Bus
M Series User Manual2-2ni.com
Calibration Circuitry
The M Series 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.
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 M Series devices, refer to the
B/E/M/S Series Calibration Procedure for NI-DAQmx by clicking Manual
Calibration Procedures on
Signal Conditioning
Chapter 2DAQ System Overview
ni.com/calibration.
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
•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.
•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.
Signal Conditioning Options
SCXI
SCXI is a front-end signal conditioning and switching system for various
measurement devices, including M Series devices. An SCXI system
consists of a rugged chassis that houses shielded signal conditioning
modules that amplify, filter, isolate, and multiplex analog signals from
thermocouples or other transducers. SCXI is designed for large
measurement systems or systems requiring high-speed acquisition.
ni.com/sensors.
System features include the following.
•Modular architecture—Choose your measurement technology
•Expandability—Expand your system to 3,072 channels
•Integration—Combine analog input, analog output, digital I/O, and
switching into a single, unified platform
•High bandwidth—Acquire signals at high rates
•Connectivity—Select from SCXI modules with thermocouple
connectors or terminal blocks
Note SCXI is not supported on PCI-6221 (37-pin) or all variants of USB-622x/625x
devices.
M Series User Manual2-4ni.com
Chapter 2DAQ System Overview
SCC
SCC is a front-end signal conditioning system for M Series plug-in data
acquisition devices. An SCC system consists of a shielded carrier that holds
up to 20 single- or dual-channel SCC modules for conditioning
thermocouples and other transducers. SCC is designed for small
measurement systems where you need only a few channels of each signal
type, or for portable applications. SCC systems also offer the most
comprehensive and flexible signal connectivity options.
System features include the following.
•Modular architecture—Select your measurement technology on a
per-channel basis
•Small-channel systems—Condition up to 16 analog input and
eight digital I/O lines
•Low-profile/portable—Integrates well with other laptop computer
measurement technologies
•High bandwidth—Acquire signals at rates up to 1.25 MHz
•Connectivity—Incorporates panelette technology to offer custom
connectivity to thermocouple, BNC, LEMO
MIL-Spec connectors
™
(B Series), and
Note PCI Express users should consider the power limits on certain SCC modules without
an external power supply. Refer to the specifications for your device, and the Disk Drive
Power Connector section of Chapter 3, Connector and LED Information, for information
about power limits and increasing the current the device can supply on the +5 V terminal.
Note SCC is not supported on the PCI-6221 (37-pin), USB-622x/625x Screw Terminal, or
USB-622x/625x BNC devices.
5B Series
5B is a front-end signal conditioning system for plug-in data acquisition
devices. A 5B system consists of eight or 16 single-channel modules that
plug into a backplane for conditioning thermocouples and other analog
signals. National Instruments offers a complete line of 5B modules,
carriers, backplanes, and accessories.
Note 5B is not supported on the PCI-6221 (37-pin), USB-622x/625x Screw Terminal, or
Note For more information about SCXI, SCC, and 5B Series products, refer to
ni.com/signalconditioning.
Cables and Accessories
NI offers a variety of products to use with M Series devices, including
cables, connector blocks, and other accessories, as follows:
•Shielded cables and cable assemblies, and unshielded ribbon cables
and cable assemblies
•Screw terminal connector blocks, shielded and unshielded
•RTSI bus cables
•SCXI modules and accessories for isolating, amplifying, exciting, and
multiplexing signals; with SCXI you can condition and acquire up to
3,072 channels
•Low-channel-count signal conditioning modules, devices, and
accessories, including conditioning for strain gauges and RTDs,
simultaneous sample and hold circuitry, and relays
Custom Cabling
For more specific information about these products, refer to
Refer to the Custom Cabling section of this chapter, the Field Wiring
Considerations section of Chapter 4, Analog Input, and Appendix A,
Device-Specific Information, for information about how to select
accessories for your M Series device.
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
ni.com.
M Series User Manual2-6ni.com
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