NI DAQ M Series User manual

PCI-6236

DAQ M Series
NI 6236 User Manual
Isolated Current Input/Voltage Output Devices
NI 6236 User Manual
May 2006
371948A-01

Support
Worldwide Technical Support and Product Information
ni.com
National Instruments Corporate Headquarters
11500 North Mopac Expressway Austin, Texas 78759-3504 USA Tel: [phone]
Worldwide Offices
Australia 1800 300 800, Austria 43 0 662 45 79 90 0, Belgium 32 0 2 757 00 20, Brazil 55 11 3262 3599,
Canada 800 433 3488, China 86 21 6555 7838, Czech Republic 420 224 235 774, Denmark 45 45 76 26 00,
Finland 385 0 9 725 725 11, France 33 0 1 48 14 24 24, Germany 49 0 89 741 31 30, India 91 80 41190000,
Israel 972 0 3 6393737, Italy 39 02 413091, Japan 81 3 5472 2970, Korea 82 02 3451 3400,
Lebanon 961 0 1 33 28 28, Malaysia 1800 887710, Mexico 01 800 010 0793, Netherlands 31 0 348 433 466,
New Zealand 0800 553 322, Norway 47 0 66 90 76 60, Poland 48 22 3390150, Portugal 351 210 311 210,
Russia 7 095 783 68 51, Singapore 1800 226 5886, Slovenia 386 3 425 4200, South Africa 27 0 11 805 8197,
Spain 34 91 640 0085, Sweden 46 0 8 587 895 00, Switzerland 41 56 200 51 51, Taiwan 886 02 2377 2222,
Thailand 662 278 6777, 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 ni.com/info and enter
the info code feedback.
©2006 National Instruments Corporation. All rights reserved.

Important Information
Warranty
The NI 6236 is warranted against defects in materials and workmanship for a period of three years 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 APARTICULAR PURPOSE. CUSTOMER’SRIGHT 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.
Trademarks
National Instruments, NI, ni.com, and LabVIEW are trademarks of National Instruments Corporation. Refer to the Terms of Use section
on ni.com/legal for more information about National Instruments trademarks.
FireWire®is the registered trademark of Apple Computer, Inc. Other product and company names mentioned herein are trademarks or trade names
of their respective companies.
Members of the National Instruments Alliance Partner Program are business entities independent from National Instruments and have no agency,
partnership, or joint-venture relationship with National Instruments.
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.

©National Instruments Corporation v NI 6236 User Manual
Contents
About This Manual
Conventions ...................................................................................................................xiii
Related Documentation..................................................................................................xiv
NI-DAQ...........................................................................................................xiv
NI-DAQmx for Linux......................................................................................xiv
NI-DAQmx Base .............................................................................................xv
LabVIEW ........................................................................................................xv
LabWindows™/CVI™......................................................................................xvi
Measurement Studio........................................................................................xvi
ANSI C without NI Application Software ......................................................xvi
.NET Languages without NI Application Software ........................................xvi
Device Documentation and Specifications......................................................xvii
Training Courses .............................................................................................xvii
Technical Support on the Web ........................................................................xvii
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
Device Accessories and Cables .....................................................................................1-2
Chapter 2
DAQ System Overview
DAQ Hardware ..............................................................................................................2-1
DAQ-STC2......................................................................................................2-2
Calibration Circuitry........................................................................................2-3
Sensors and Transducers................................................................................................2-3
Cables and Accessories..................................................................................................2-4
Custom Cabling ...............................................................................................2-4
Programming Devices in Software ................................................................................2-5
Chapter 3
Connector Information
I/O Connector Signal Descriptions ................................................................................3-1
RTSI Connector Pinout..................................................................................................3-2

Contents
NI 6236 User Manual vi ni.com
Chapter 4
Analog Input
Analog Input Circuitry .................................................................................................. 4-1
Analog Input Range....................................................................................................... 4-2
Connecting Analog Current Input Signals .................................................................... 4-3
Method 1 ......................................................................................................... 4-3
Method 2 ......................................................................................................... 4-4
Analog Input Ground-Reference Settings ..................................................................... 4-5
Configuring AI Ground-Reference Settings in Software................................ 4-7
Multichannel Scanning Considerations......................................................................... 4-8
Use Short High-Quality Cabling..................................................................... 4-8
Minimize Current Step between Adjacent Channels ...................................... 4-8
Avoid Scanning Faster Than Necessary ......................................................... 4-9
Example 1 ......................................................................................... 4-9
Example 2 ......................................................................................... 4-9
Analog Input Data Acquisition Methods....................................................................... 4-10
Software-Timed Acquisitions ......................................................................... 4-10
Hardware-Timed Acquisitions........................................................................ 4-10
Buffered ............................................................................................ 4-10
Non-Buffered.................................................................................... 4-11
Analog Input Triggering................................................................................................ 4-11
Field Wiring Considerations.......................................................................................... 4-11
Analog Input Timing Signals ........................................................................................ 4-12
AI Sample Clock Signal.................................................................................. 4-15
Using an Internal Source .................................................................. 4-15
Using an External Source ................................................................. 4-15
Routing AI Sample Clock Signal to an Output Terminal................. 4-16
Other Timing Requirements ............................................................. 4-16
AI Sample Clock Timebase Signal ................................................................. 4-17
AI Convert Clock Signal................................................................................. 4-17
Using an Internal Source .................................................................. 4-18
Using an External Source ................................................................. 4-18
Routing AI Convert Clock Signal to an Output Terminal................ 4-18
Using a Delay from Sample Clock to Convert Clock ...................... 4-19
Other Timing Requirements ............................................................. 4-19
AI Convert Clock Timebase Signal ................................................................ 4-20
AI Hold Complete Event Signal ..................................................................... 4-20
AI Start Trigger Signal.................................................................................... 4-21
Using a Digital Source...................................................................... 4-21
Routing AI Start Trigger to an Output Terminal .............................. 4-21
AI Reference Trigger Signal ........................................................................... 4-22
Using a Digital Source...................................................................... 4-23
Routing AI Reference Trigger Signal to an Output Terminal .......... 4-23

Contents
©National Instruments Corporation vii NI 6236 User Manual
AI Pause Trigger Signal ..................................................................................4-23
Using a Digital Source ......................................................................4-23
Routing AI Pause Trigger Signal to an Output Terminal .................4-24
Getting Started with AI Applications in Software.........................................................4-24
Chapter 5
Analog Output
Analog Output Circuitry ................................................................................................5-1
Minimizing Glitches on the Output Signal ....................................................................5-2
Analog Output Data Generation Methods .....................................................................5-2
Software-Timed Generations...........................................................................5-2
Hardware-Timed Generations .........................................................................5-3
Non-Buffered ....................................................................................5-3
Buffered ............................................................................................5-3
Analog Output Triggering .............................................................................................5-4
Connecting Analog Voltage Output Signals..................................................................5-4
Analog Output Timing Signals ......................................................................................5-5
AO Start Trigger Signal...................................................................................5-6
Using a Digital Source ......................................................................5-6
Routing AO Start Trigger Signal to an Output Terminal..................5-7
AO Pause Trigger Signal.................................................................................5-7
Using a Digital Source ......................................................................5-8
Routing AO Pause Trigger Signal to an Output Terminal................5-8
AO Sample Clock Signal.................................................................................5-8
Using an Internal Source...................................................................5-9
Using an External Source..................................................................5-9
Routing AO Sample Clock Signal to an Output Terminal................5-9
Other Timing Requirements..............................................................5-9
AO Sample Clock Timebase Signal................................................................5-10
Getting Started with AO Applications in Software .......................................................5-11
Chapter 6
Digital Input and Output
I/O Protection.................................................................................................................6-1
Programmable Power-Up States....................................................................................6-2
Connecting Digital I/O Signals......................................................................................6-2
Getting Started with DIO Applications in Software......................................................6-3

Contents
NI 6236 User Manual viii ni.com
Chapter 7
Counters
Counter Input Applications ........................................................................................... 7-2
Counting Edges ............................................................................................... 7-2
Single Point (On-Demand) Edge Counting ...................................... 7-2
Buffered (Sample Clock) Edge Counting......................................... 7-3
Non-Cumulative Buffered Edge Counting ....................................... 7-4
Controlling the Direction of Counting.............................................. 7-4
Pulse-Width Measurement.............................................................................. 7-5
Single Pulse-Width Measurement .................................................... 7-5
Buffered Pulse-Width Measurement ................................................ 7-5
Period Measurement ....................................................................................... 7-6
Single Period Measurement.............................................................. 7-7
Buffered Period Measurement.......................................................... 7-7
Semi-Period Measurement.............................................................................. 7-8
Single Semi-Period Measurement .................................................... 7-8
Buffered Semi-Period Measurement ................................................ 7-9
Frequency Measurement ................................................................................. 7-9
Method 1—Measure Low Frequency with One Counter ................. 7-9
Method 1b—Measure Low Frequency with One Counter
(Averaged) ..................................................................................... 7-10
Method 2—Measure High Frequency with Two Counters .............. 7-11
Method 3—Measure Large Range of Frequencies Using
Two Counters................................................................................. 7-12
Choosing a Method for Measuring Frequency ................................. 7-13
Position Measurement..................................................................................... 7-15
Measurements Using Quadrature Encoders...................................... 7-15
Measurements Using Two Pulse Encoders ...................................... 7-17
Two-Signal Edge-Separation Measurement ................................................... 7-18
Single Two-Signal Edge-Separation Measurement.......................... 7-18
Buffered Two-Signal Edge-Separation Measurement...................... 7-19
Counter Output Applications......................................................................................... 7-20
Simple Pulse Generation................................................................................. 7-20
Single Pulse Generation.................................................................... 7-20
Single Pulse Generation with Start Trigger...................................... 7-20
Retriggerable Single Pulse Generation............................................. 7-21
Pulse Train Generation.................................................................................... 7-22
Continuous Pulse Train Generation.................................................. 7-22
Frequency Generation ..................................................................................... 7-23
Using the Frequency Generator ........................................................ 7-23
Frequency Division ......................................................................................... 7-24
Pulse Generation for ETS ............................................................................... 7-24

Contents
©National Instruments Corporation ix NI 6236 User Manual
Counter Timing Signals .................................................................................................7-25
Counter nSource Signal..................................................................................7-25
Routing a Signal to Counter nSource...............................................7-26
Routing Counter nSource to an Output Terminal ............................7-26
Counter nGate Signal .....................................................................................7-27
Routing a Signal to Counter nGate ..................................................7-27
Routing Counter nGate to an Output Terminal................................7-27
Counter nAux Signal ......................................................................................7-27
Routing a Signal to Counter nAux...................................................7-27
Counter nA, Counter nB, and Counter nZ Signals.......................................7-28
Routing Signals to A, B, and Z Counter Inputs ................................7-28
Routing Counter nZ Signal to an Output Terminal..........................7-28
Counter nUp_Down Signal ............................................................................7-28
Counter nHW Arm Signal..............................................................................7-28
Routing Signals to Counter nHW Arm Input...................................7-29
Counter nInternal Output and Counter nTC Signals .....................................7-29
Routing Counter nInternal Output to an Output Terminal...............7-29
Frequency Output Signal.................................................................................7-29
Routing Frequency Output to a Terminal .........................................7-29
Default Counter Terminals ............................................................................................7-30
Counter Triggering ........................................................................................................7-31
Arm Start Trigger ............................................................................................7-31
Start Trigger.....................................................................................................7-31
Pause Trigger...................................................................................................7-31
Other Counter Features..................................................................................................7-32
Cascading Counters .........................................................................................7-32
Counter Filters .................................................................................................7-32
Prescaling ........................................................................................................7-33
Duplicate Count Prevention ............................................................................7-34
Example Application That Works Correctly
(No Duplicate Counting)................................................................7-34
Example Application That Works Incorrectly
(Duplicate Counting)......................................................................7-35
Example Application That Prevents Duplicate Count ......................7-35
When To Use Duplicate Count Prevention.......................................7-36
Enabling Duplicate Count Prevention in NI-DAQmx ......................7-37
Synchronization Modes ...................................................................................7-37
80 MHz Source Mode .......................................................................7-38
Other Internal Source Mode..............................................................7-38
External Source Mode.......................................................................7-38

Contents
NI 6236 User Manual x ni.com
Chapter 8
PFI
Using PFI Terminals as Timing Input Signals .............................................................. 8-2
Exporting Timing Output Signals Using PFI Terminals............................................... 8-3
Using PFI Terminals as Static Digital Inputs and Outputs............................................ 8-3
Connecting PFI Input Signals........................................................................................ 8-3
PFI Filters ...................................................................................................................... 8-4
I/O Protection ................................................................................................................ 8-6
Programmable Power-Up States.................................................................................... 8-6
Chapter 9
Isolation and Digital Isolators
Digital Isolation ............................................................................................................. 9-2
Benefits of an Isolated DAQ Device ............................................................................. 9-2
Reducing Common-Mode Noise................................................................................... 9-2
Creating an AC Return Path............................................................................ 9-3
Non-Isolated Systems ....................................................................... 9-3
Isolated Systems ............................................................................... 9-3
Chapter 10
Digital Routing and Clock Generation
Clock Routing................................................................................................................ 10-1
80 MHz Timebase ........................................................................................... 10-2
20 MHz Timebase ........................................................................................... 10-2
100 kHz Timebase .......................................................................................... 10-2
External Reference Clock ............................................................................... 10-2
10 MHz Reference Clock................................................................................ 10-3
Synchronizing Multiple Devices ................................................................................... 10-3
Real-Time System Integration Bus (RTSI) ................................................................... 10-3
RTSI Connector Pinout ................................................................................... 10-4
Using RTSI as Outputs ................................................................................... 10-5
Using RTSI Terminals as Timing Input Signals............................................. 10-6
RTSI Filters..................................................................................................... 10-6
PXI Clock and Trigger Signals...................................................................................... 10-8
PXI_CLK10 .................................................................................................... 10-8
PXI Triggers.................................................................................................... 10-8
PXI_STAR Trigger ......................................................................................... 10-8
PXI_STAR Filters........................................................................................... 10-9

Contents
©National Instruments Corporation xi NI 6236 User Manual
Chapter 11
Bus Interface
DMA Controllers ...........................................................................................................11-1
PXI Considerations ........................................................................................................11-2
PXI Clock and Trigger Signals........................................................................11-2
PXI and PXI Express.......................................................................................11-2
Using PXI with CompactPCI ..........................................................................11-3
Data Transfer Methods ..................................................................................................11-3
Direct Memory Access (DMA) .......................................................................11-3
Interrupt Request (IRQ)...................................................................................11-4
Programmed I/O ..............................................................................................11-4
Changing Data Transfer Methods between DMA and IRQ ............................11-4
Chapter 12
Triggering
Triggering with a Digital Source ...................................................................................12-1
Appendix A
NI 6236 Device Information
NI 6236 Pinout...............................................................................................................A-1
NI 6236 Specifications...................................................................................................A-3
NI 6236 Accessory and Cabling Options ......................................................................A-3
Appendix B
Troubleshooting
Analog Input ..................................................................................................................B-1
Analog Output................................................................................................................B-2
Counters .........................................................................................................................B-3
Appendix C
Technical Support and Professional Services
Glossary
Index

©National Instruments Corporation xiii NI 6236 User Manual
About This Manual
The NI 6236 User Manual contains information about using the NI 6236
M Series data acquisition (DAQ) devices with NI-DAQ 8.1 and later.
National Instruments 6236 devices feature four analog current input (AI)
channels, four analog voltage output (AO) channels, two counters, six lines
of digital input (DI), and four lines of digital output (DO).
Conventions
The following conventions appear 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.
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.

About This Manual
NI 6236 User Manual xiv ni.com
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 8.1 or later, and where applicable, version 7.0 or later of the NI
application software.
NI-DAQ
The DAQ 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»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.
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.

About This Manual
©National Instruments Corporation xv NI 6236 User Manual
NI-DAQmx Base
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. Select Start»All
Programs»National Instruments»NI-DAQmx Base»Documentation»
Getting Started Guide.
The NI-DAQmx Base Readme lists which devices are supported by this
version of NI-DAQmx Base. Select Start»All Programs»National
Instruments»NI-DAQmx Base»Documentation»Readme.
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. Select Start»All Programs»
National Instruments»NI-DAQmx Base»Documentation»C Function
Reference Manual.
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.

About This Manual
NI 6236 User Manual xvi ni.com
•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/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
The NI Measurement Studio Help contains function reference,
measurement concepts, and a walkthrough for using the Measurement
Studio NI-DAQmx .NET and Visual C++ class libraries. This help
collection is integrated into the Microsoft Visual Studio .NET
documentation. In Visual Studio .NET, select Help»Contents.
Note You must have Visual Studio .NET installed to view the NI Measurement Studio
Help.
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.
.NET Languages without NI Application Software
The NI Measurement Studio Help contains function reference and
measurement concepts for using the Measurement Studio NI-DAQmx
.NET and Visual C++ class libraries. This help collection is integrated into
the Visual Studio .NET documentation. In Visual Studio .NET, select
Help»Contents.
Note You must have Visual Studio .NET installed to view the NI Measurement Studio
Help.

About This Manual
©National Instruments Corporation xvii NI 6236 User Manual
Device Documentation and Specifications
The NI 6236 Specifications contains all specifications for NI 6236
M Series devices.
NI-DAQ 7.0 and later includes the Device Document Browser, which
contains online documentation for supported DAQ, SCXI, and switch
devices, such as help files describing device pinouts, features, and
operation, and PDF files of the printed device documents. 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.
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 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 www.adobe.com to download Acrobat Reader. Refer to the
National Instruments Product Manuals Library at ni.com/manuals for
updated documentation resources.

©National Instruments Corporation 1-1 NI 6236 User Manual
1
Getting Started
M Series NI 6236 devices feature four analog current input (AI) channels,
four analog voltage output (AO) channels, two counters, six lines of digital
input (DI), and four lines of digital output (DO). If you have not already
installed your device, refer to the DAQ Getting Started Guide. For NI 6236
device specifications, refer to the NI 6236 Specifications 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.
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 and PXI devices, as well as
accessories and cables.
Device Pinouts
Refer to Appendix A, NI 6236 Device Information, for the NI 6236 device
pinout.

Chapter 1 Getting Started
NI 6236 User Manual 1-2 ni.com
Device Specifications
Refer to the NI 6236 Specifications, available on the NI-DAQ Device
Document Browser or ni.com/manuals, for more detailed information
about NI 6236 devices.
Device Accessories and Cables
NI offers a variety of accessories and cables to use with your DAQ device.
Refer to Appendix A, NI 6236 Device Information, or ni.com for more
information.

©National Instruments Corporation 2-1 NI 6236 User Manual
2
DAQ System Overview
Figure 2-1 shows a typical DAQ system, which includes sensors,
transducers, 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.
Figure 2-1. Components of a Typical DAQ System
DAQ Hardware
DAQ hardware digitizes input signals, performs D/A conversions to
generate analog output signals, and measures and controls digital I/O
signals. Figure 2-2 features the components of NI 6236 devices.
Sensors and
Transducers
DAQ
Hardware
Personal
Computer
DAQ
Software
Cables and
Accessories

Chapter 2 DAQ System Overview
NI 6236 User Manual 2-2 ni.com
Figure 2-2. General NI 6236 Block Diagram
DAQ-STC2
The DAQ-STC2 implements a high-performance digital engine for
NI 6236 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 and AO 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
• Static DIO signals
• PLL for clock synchronization
• PCI/PXI interface
• Independent scatter-gather DMA controllers for all acquisition and
generation functions
Analog Output
Analog Input
PFI/Static DI
PFI/Static DO
Digital
Routing
and Clock
Generation
Bus
Interface
I/O Connector
RTSI
Digital
Isolators
Isolation
Barrier
Bus
Counters