Important Information
Warranty
The NI PXIe-6672 is 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
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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
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to reproduce materials that you may reproduce in accordance with the terms of any applicable license or other legal restriction.
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on ni.com/legal for more information about National Instruments trademarks.
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,
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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 media, 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
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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
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LIMITATION, THE APPROPRIATE DESIGN, PROCESS AND SAFETY LEVEL OF SUCH SYSTEM OR APPLICATION.
About This Manual
Conventions ...................................................................................................................vii
Chapter 1
Introduction
Unpacking......................................................................................................................1-2
Chapter 2
Installing the Software...................................................................................................2-1
Chapter 3
Access LED.....................................................................................................3-4
Direct Digital Synthesis (DDS).......................................................................3-7
PXI_CLK10 and TCXO..................................................................................3-8
Routing Signals..............................................................................................................3-9
Determining Sources and Destinations ...........................................................3-11
Using Front Panel PFIs As Inputs.....................................................3-12
Using Front Panel PFIs As Outputs ..................................................3-13
Using the PXI Triggers .....................................................................3-14
Using the PXI Star Triggers..............................................................3-15
© National Instruments Corporation
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Contents
Choosing the Type of Routing........................................................................ 3-15
Synchronous Routing ....................................................................... 3-17
Using the PXI_CLK10 PLL.......................................................................................... 3-19
Chapter 4
Factory Calibration........................................................................................................ 4-1
TCXO Frequency............................................................................................ 4-1
PXI_CLK10 Phase.......................................................................................... 4-1
DDS Start Trigger Phase................................................................................. 4-1
DDS Initial Phase............................................................................................ 4-2
Additional Information.................................................................................................. 4-2
Appendix A
Technical Support and Professional Services
Glossary
Index
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About This Manual
Thank you for purchasing the National Instruments NI PXIe-6672 Timing
and Synchronization Module. The NI PXIe-6672 enables you to pass
PXI timing and trigger signals between two or more PXI Express chassis.
The NI PXIe-6672 can generate and route clock signals between devices in
multiple chassis, providing a method to synchronize multiple devices
in a multichassis PXI Express system.
This manual describes the electrical and mechanical aspects of the
NI PXIe-6672 and contains information concerning its operation and
programming.
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 tip, which alerts you to advisory information.
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
the product, refer to the Safety Information section of Chapter 1,
Introduction, for 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 and hardware labels.
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.
© National Instruments Corporation
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About This Manual
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.
NI PXIe-6672
This phrase refers to the NI PXIe-6672 module for the PXI Express bus.
National Instruments Documentation
The NI PXIe-6672 User Manual is one piece of the documentation set for
your measurement system. You could have any of several other documents
describing your hardware and software. Use the documentation you have
as follows:
•
•
Measurement hardware documentation—This documentation contains
detailed information about the measurement hardware that plugs into
or is connected to the computer. Use this documentation for hardware
installation and configuration instructions, specifications about the
measurement hardware, and application hints.
Software documentation—Refer to the NI-Sync User Manual,
available at ni.com/manuals.
You can download NI documentation from ni.com/manuals.
Related Documentation
The following documents contain information that you might find helpful
as you read this manual:
•
PICMG 2.0 R3.0, CompactPCI Core Specification, available from
PICMG at www.picmg.org
•
PXI-5 PXI Express Hardware Specification, Revision 1.0, available
from www.pxisa.org
•
•
•
NI-VISA User Manual, available from ni.com/manuals
NI-VISA Help, included with the NI-VISA software
NI-Sync User Manual, available from ni.com/manuals
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1
Introduction
The NI PXIe-6672 timing and triggering module enables you to pass
PXI timing signals between two or more PXI Express chassis. The
NI PXIe-6672 module generates and routes clock signals between devices
in multiple chassis, providing a method for synchronizing multiple devices
in a PXI Express system.
What You Need to Get Started
To set up and use the NI PXIe-6672, you need the following items:
❑ NI PXIe-6672 Timing and Triggering Module
❑ NI PXIe-6672 User Manual
❑ NI-Sync CD
❑ An Application Development Environment such as:
–
–
–
LabVIEW
LabWindows™/CVI™
Microsoft Visual C++ (MSVC)
❑ PXI Express chassis
❑ PXI Express embedded controller or a desktop computer connected to
the PXI Express chassis using MXI-Express hardware
For information on using the driver software for synchronization, refer
to the NI-Sync User Manual, which you can find on the NI-Sync CD or
download from ni.com/manuals.
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Chapter 1
Introduction
Unpacking
The NI PXIe-6672 is shipped in an antistatic package to prevent
electrostatic damage to the module. Electrostatic discharge (ESD)
can damage several components on the module.
Caution Never touch the exposed pins of connectors.
To avoid such damage in handling the module, take the following
precautions:
•
Ground yourself using a grounding strap or by touching a grounded
object.
•
Touch the antistatic package to a metal part of the computer chassis
before removing the module from the package.
Remove the module from the package and inspect the module for loose
components or any sign of damage. Notify NI if the module appears
damaged in any way. Do not install a damaged module into the computer.
Store the NI PXIe-6672 in the antistatic envelope when not in use.
Software Programming Choices
When programming the NI PXIe-6672, you can use NI application
development environment (ADE) software such as LabVIEW or
LabWindows/CVI, or you can use other ADEs such as Visual C/C++.
LabVIEW features interactive graphics, a state-of-the-art interface,
and a powerful graphical programming language. The LabVIEW Data
Acquisition VI Library, a series of virtual instruments for using LabVIEW
with National Instruments DAQ hardware, is included with LabVIEW.
LabWindows/CVI is a complete ANSI C ADE that features an interactive
user interface, code generation tools, and the LabWindows/CVI Data
Acquisition and Easy I/O libraries.
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Chapter 1
Introduction
Safety Information
The following section contains important safety information that you must
follow when installing and using the product.
Do not operate the product in a manner not specified in this document.
Misuse of the product can result in a hazard. You can compromise the
safety protection built into the product if the product is damaged in any
way. If the product is damaged, return it to National Instruments for repair.
Do not substitute parts or modify the product except as described in this
document. Use the product only with the chassis, modules, accessories, and
cables specified in the installation instructions. You must have all covers
and filler panels installed during operation of the product.
Do not operate the product in an explosive atmosphere or where there may
be flammable gases or fumes. If you must operate the product in such an
environment, it must be in a suitably rated enclosure.
If you need to clean the product, use a soft, nonmetallic brush. The product
must be completely dry and free from contaminants before you return it to
service.
Operate the product only at or below Pollution Degree 2. Pollution is
foreign matter in a solid, liquid, or gaseous state that can reduce dielectric
strength or surface resistivity. The following is a description of pollution
degrees:
•
Pollution Degree 1 means no pollution or only dry, nonconductive
pollution occurs. The pollution has no influence.
•
Pollution Degree 2 means that only nonconductive pollution occurs in
most cases. Occasionally, however, a temporary conductivity caused
by condensation must be expected.
•
Pollution Degree 3 means that conductive pollution occurs, or dry,
nonconductive pollution occurs that becomes conductive due to
condensation.
You must insulate signal connections for the maximum voltage for which
the product is rated. Do not exceed the maximum ratings for the product.
Do not install wiring while the product is live with electrical signals. Do not
remove or add connector blocks when power is connected to the system.
Avoid contact between your body and the connector block signal when hot
swapping modules. Remove power from signal lines before connecting
them to or disconnecting them from the product.
© National Instruments Corporation
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Chapter 1
Introduction
Operate the product at or below the installation category1 marked on the
hardware label. Measurement circuits are subjected to working voltages2
and transient stresses (overvoltage) from the circuit to which they are
connected during measurement or test. Installation categories establish
standard impulse withstand voltage levels that commonly occur in
electrical distribution systems. The following is a description of installation
categories:
•
Installation Category I is for measurements performed on circuits not
directly connected to the electrical distribution system referred to as
MAINS3 voltage. This category is for measurements of voltages from
specially protected secondary circuits. Such voltage measurements
include signal levels, special equipment, limited-energy parts of
equipment, circuits powered by regulated low-voltage sources,
and electronics.
•
•
Installation Category II is for measurements performed on circuits
directly connected to the electrical distribution system. This category
refers to local-level electrical distribution, such as that provided by a
standard wall outlet (for example, 115 V for U.S. or 230 V for Europe).
Examples of Installation Category II are measurements performed on
household appliances, portable tools, and similar products.
Installation Category III is for measurements performed in the building
installation at the distribution level. This category refers to
measurements on hard-wired equipment such as equipment in fixed
installations, distribution boards, and circuit breakers. Other examples
are wiring, including cables, bus-bars, junction boxes, switches,
socket-outlets in the fixed installation, and stationary motors with
permanent connections to fixed installations.
•
Installation Category IV is for measurements performed at the primary
electrical supply installation (<1,000 V). Examples include electricity
meters and measurements on primary overcurrent protection devices
and on ripple control units.
1
Installation categories, also referred to as measurement categories, are defined in electrical safety standard IEC 61010-1.
2
3
Working voltage is the highest rms value of an AC or DC voltage that can occur across any particular insulation.
MAINS is defined as a hazardous live electrical supply system that powers equipment. Suitably rated measuring circuits may
be connected to the MAINS for measuring purposes.
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2
Installing and Configuring
This chapter describes how to install the NI PXIe-6672 hardware and
software and how to configure the device.
Installing the Software
Refer to the readme.htm file that accompanies the NI-Sync CD for
software installation directions.
Note Be sure to install the driver software before installing the NI PXIe-6672 hardware.
Installing the Hardware
warnings about installing new modules.
1. Power off and unplug the chassis.
2. Locate the System Timing Slot in your chassis. It is marked by either
a square glyph shown in Figure 2-1, or a square glyph with a circle
inside of it, as shown in Figure 2-2.
Figure 2-1. System Timing Device Slot Indicator Glyph without Circle
Figure 2-2. System Timing Device Slot Indicator Glyph on the NI PXIe-1062Q Chassis
© National Instruments Corporation
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Installing and Configuring
Note The slot number printed on the glyph may vary from chassis to chassis.
The circle inside of the square indicates that the slot may also be used as a PXI Express
peripheral slot.
3. Remove the filler panel for the PXI slot you located in step 2.
4. Ground yourself using a grounding strap or by holding a grounded
object. Follow the ESD protection precautions described in the
Unpacking section of Chapter 1, Introduction.
5. Remove any packing material from the front panel screws and
backplane connectors.
6. Insert the NI PXIe-6672 into the PXI Express slot. Use the
injector/ejector handle to fully insert the module into the chassis.
7. Screw the front panel of the device to the front panel mounting rail of
the chassis.
8. Visually verify the installation. Make sure the module is not touching
other modules or components and is fully inserted into the slot.
9. Plug in and power on the chassis.
The NI PXIe-6672 is now installed.
Configuring the Module
The NI PXIe-6672 is completely software configurable. The system
software automatically allocates all module resources.
The two LEDs on the front panel provide information about module status.
The front panel description sections of Chapter 3, Hardware Overview,
describe the LEDs in greater detail.
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Chapter 3
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PXI_CLK10_IN
PXI_CLK10
AC Coupled
Clock Detector
CLKIN
PLL
TCXO
TCXO
Calibration
DAC
TCXO
Clock
CLKOUT
CLKIN
DDS
DDS Clock
Driver/
PFI 0
PFI 1
PFI 2
PFI 3
PFI 4
PFI 5
PXI_STAR<0..16>
PXI_TRIG<0..7>
Comparator
CLOCK and
TRIGGER
Routing
PFI 0
Threshold
DAC
Driver/
Comparator
PFI 1
Threshold
DAC
Driver/
Comparator
PCI Interface
PFI 2
Threshold
DAC
Driver/
Comparator
PFI 3
Threshold
DAC
Driver/
Comparator
PFI 4
Threshold
DAC
Driver/
Comparator
PFI 5
Threshold
DAC
Figure 3-1. Functional Overview of the NI PXIe-6672
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NI PXIe-6672 Front Panel
Figure 3-2 shows the connectors and LEDs on the front panel of the
NI PXIe-6672.
NI PXIe-6672
Timing Module
1
3
2
ACCESS
ACTIVE
CLK
OUT
CLK
IN
4
PFI 0
PFI 1
PFI 2
PFI 3
PFI 4
PFI 5
5
1
2
3
Access LED
Active LED
CLKOUT Connector
4
5
CLKIN Connector
PFI <0..5> Connectors
Figure 3-2. NI PXIe-6672 Front Panel
© National Instruments Corporation
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Chapter 3
Hardware Overview
Access LED
The Access LED indicates the communication status of the NI PXIe-6672.
Refer to Figure 3-2 for the location of the Access LED.
Table 3-1 summarizes what the Access LED colors represent.
Table 3-1. Access LED Color Indication
Color
Off
Status
Module is not yet functional.
Driver has initialized the module.
Green
Amber
Module is being accessed. The Access LED
flashes amber for 50 ms when the module is
accessed.
Active LED
The Active LED can indicate an error or phase-locked loop (PLL) activity.
You can change the Active LED to amber, unless an error overrides the
Tip Changing the Active LED color to amber is helpful when you want to identify devices
in a multichassis situation or when you want an indication that your application has
reached a predetermined section of the code.
Table 3-2 illustrates the meaning of each Active LED color.
Table 3-2. Active LED Color Quick Reference Table
PXI_CLK10
Stopped
PLL
Error
User
Setting
PLL
Active
Color
Red
Yes
No
No
No
Yes
No
No
No
—
Yes
No
No
—
—
Amber
Green
Off
Yes
No
a PLL error.
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Chapter 3
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Connectors
This section describes the connectors on the front panel of the
NI PXIe-6672.
•
•
•
CLKIN—Clock Input. This connector supplies the module with
a clock that can be programmatically routed to the onboard PLL
for use as a reference or routed directly to the PXI backplane
(PXI_CLK10_IN) for distribution to the other modules in the chassis.
CLKOUT—Clock Output. This connector is used to source
a clock that can be routed programmatically from the
temperature-compensated crystal oscillator (TCXO), direct
digital synthesis (DDS), or backplane clock (PXI_CLK10).
PFI <0..5>—Programmable Function Interface <0..5>. These
can be used as a clock input for internally synchronizing other signals.
Refer to the Synchronous Routing section for more information about
this functionality. You can program the behavior of these PFI
connections individually.
Refer to Figure 3-2 for a diagram showing the locations of these
connections on the NI PXIe-6672 front panel.
Caution Connections that exceed any of the maximum ratings of input or output signals
on the NI PXIe-6672 can damage the module and the computer. NI is not liable for any
damage resulting from such signal connections.
Hardware Features
The NI PXIe-6672 perform two broad functions:
•
•
Generating clock and trigger signals
Routing internally or externally generated signals from one location
to another
© National Instruments Corporation
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Table 3-3 outlines the function and direction of the signals discussed in
detail in the remainder of this chapter.
Table 3-3. Signal Descriptions
Signal Name
Direction
Description
PXI_CLK10_IN
Out
This is a signal that can replace the native 10 MHz oscillator
on the PXI backplane. PXI_CLK10_IN may originate from
the onboard TCXO or from an external source.
PXI_CLK10
In
This signal is the PXI 10 MHz backplane clock. By default,
this signal is the output of the native 10 MHz oscillator in the
chassis. An NI PXIe-6672 in the System Timing Slot can
replace this signal with PXI_CLK10_IN.
TCXO Clock
CLKIN
Out
In
This is the output of the 10 MHz TCXO. The TCXO is an
extremely stable and accurate frequency source.
CLKIN is a signal connected to the SMB input pin of the
same name. CLKIN can serve as PXI_CLK10_IN, a phase
lock reference for the TCXO, or as a source for routing to
PXI_STAR.
CLKOUT
Out
Out
CLKOUT is the signal on the SMB output pin of the same
name. Either the TCXO clock, DDS clock, or PXI_CLK10
may be routed to this location.
DDS Clock
This is the output of the DDS. The DDS frequency can be
programmed with fine granularity from 1 Hz to 105 MHz.
The DDS chip automatically phase-locks to PXI_CLK10.
PXI_STAR <0..16>
In/Out
The PXI star trigger bus connects the System Timing Slot to
all other slots in a star configuration. The electrical paths of
each star line are closely matched to minimize intermodule
skew. An NI PXIe-6672 in System Timing Slot can route
signals to all other slots using the star trigger bus.
PFI <0..5>
In/Out
In/Out
The Programmable Function Interface pins on the
NI PXIe-6672 route timing and triggering signals between
multiple PXI chassis. A wide variety of input and output
signals can be routed to or from the PFI lines.
PXI_TRIG <0..7>
The PXI trigger bus consists of eight digital lines shared
among all slots in the PXI chassis. The NI PXIe-6672 can
route a wide variety of signals to and from these lines.
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Chapter 3
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The remainder of this chapter describes how these signals are used,
acquired, and generated by the NI PXIe-6672 hardware, and explains
how you can route the signals between various locations to synchronize
multiple measurement devices and PXI chassis.
Clock Generation
The NI PXIe-6672 can generate two types of clock signals. The first clock
is generated using the onboard DDS chip, and the second is generated with
a precise 10 MHz oscillator. The following sections describe the two types
of clock generation and explain the considerations for choosing either type.
Direct Digital Synthesis (DDS)
DDS is a method of generating a clock with programmable frequency.
DDS consists of a frequency tuning word, an accumulator, a sine-lookup
table, a D/A converter (DAC), and a comparator.
The frequency tuning word is a number that specifies the desired
frequency. Each master clock cycle, the frequency tuning word is added to
the accumulator, which rolls over when it gets to its maximum value. The
accumulator value is used to get a point in the sine-lookup table, which is
converted to an analog voltage by the DAC. For example, if the sine table
is 128 points long, and the frequency tuning word is one, the accumulator
takes 128 clock cycles to output one sine wave. If you change the frequency
tuning word to 3, the accumulator steps through the sine table three times
as fast, and outputs a sine wave in 128/3, or 42.6, clock cycles.
The output of the DAC is run through an analog filter to smooth the sine
wave. The filtered output is then run through a comparator, which changes
the output to a square wave with the specified frequency.
You can specify the programmable DDS frequency on the NI PXIe-6672
with a precision of approximately .07 Hz within the range 1 Hz to
105 MHz. The accuracy of the frequency depends on the PXI_CLK10
reference clock, so a precise 10 MHz source improves the accuracy of the
DDS output. You can replace the 10 MHz clock with the TCXO for more
accurate DDS timing.
When the DDS is programmed an update signal must be sent to it before it
will begin operating as programmed. The source for this update signal is
either immediate (DDS starts outputting the programmed frequency as
soon as software programs it) or one of the eight PXI triggers. When one
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Hardware Overview
of the PXI trigger lines is used as the source for the update, frequency
generation will not start until a rising edge occurs on the PXI trigger
selected.
Note NI-Sync software defaults to an immediate update. If a PXI trigger is used instead,
the user must specify the update signal source before setting any of the other DDS
properties.
When more then one NI PXIe-6672 is used in a multiple chassis setup, the
DDS frequency of both boards can be synchronized. The DDS system
common 10 MHz clock, the DDS outputs will also be phase locked (refer
to the Using the PXI_CLK10 PLL section for information on how to ensure
that two or more chassis have close PXI_CLK10 phase alignment). To fully
synchronize the DDS outputs a common update signal source must be used
and routed to the selected PXI trigger. A synchronous route to PXI_CLK10
provides the best results. Refer to the Routing Signals section for details on
routing trigger signals.
The NI PXIe-6672 DDS can adjust the phase of the generated clock by up
to 5 ns. This may be used to tighten the synchronization between two or
more DDS devices in a multi-chassis setup, or to compensate for delays
caused by different cable lengths.
PXI_CLK10 and TCXO
The NI PXIe-6672 features a precision 10 MHz TCXO. The frequency
accuracy of this clock is several orders of magnitude greater than the
frequency accuracy of the native 10 MHz PXI backplane clock
(PXI_CLK10).
The TCXO contains circuitry to measure the temperature of the oscillator.
It uses the temperature to adjust its frequency output according to the
crystal’s known frequency variation across its operating temperature range.
An NI PXIe-6672 module in the System Timing Slot of a PXI Express
chassis can replace the native PXI 10 MHz backplane frequency reference
clock (PXI_CLK10) with the more stable and accurate output of the
TCXO. All other PXI modules in the chassis that reference the 10 MHz
backplane clock benefit from this more accurate frequency reference.
Furthermore, the DDS chip on the NI PXIe-6672 references its output to
the backplane clock and also takes advantage of the superior TCXO
accuracy. The TCXO does not automatically replace the native 10 MHz
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clock; this feature must be explicitly enabled in software. The TCXO
output also can be routed out to the CLKOUT connector.
In addition to replacing the native backplane clock directly, the TCXO can
phase lock to an external frequency source. This operation is discussed in
detail in the Using the PXI_CLK10 PLL section.
Routing Signals
The NI PXIe-6672 has versatile trigger routing capabilities. It can
route signals to and from the front panel, the PXI triggers, and the PXI star
triggers.
The CLKIN SMB input on the NI PXIe-6672 may be used for PXI_CLK10
replacement by either routing a 10 MHz signal directly from the CLKIN
input to PXI_CLK10_IN, or by using the CLKIN input as a phase lock
reference for the TCXO. When phase locking the TCXO to CLKIN,
CLKIN may be any multiple of 1 MHz to 105 MHz. In addition, CLKIN is
a valid source for PXI_Star.
The CLKOUT SMB on the NI PXIe-6672 may also be used to route the
TCXO, PXI_CLK10, or DDS Clock.
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Figures 3-3 and 3-4 summarize the routing features of the NI PXIe-6672.
The remainder of this chapter details the capabilities and constraints of
the routing architecture.
28
*PXI_STAR<0..16>,
Selection
Selection
Circuitry
PFI 0
PXI_STAR 0
PXI_TRIG<0..7>,
PFI<0..5>, and
Circuitry
SOURCE*
Software Trigger are
routed to SOURCE
of each Selection
Circuitry block.
Selection
Circuitry
Selection
Circuitry
PFI 1
CLKIN
PXI_STAR 1
Selection
Circuitry
Selection
Circuitry
PFI 5
PXI_STAR 16
PXI_TRIG 0
3
SYNCHRONIZATION
CLOCKS for PFI<0..5>
Selection
Circuitry
PFI 0
DDS
Selection
Circuitry
PXI_TRIG 1
÷2N
÷2M
PXI_CLK10
PFI 0
Selection
Circuitry
PXI_TRIG 7
SYNCHRONIZATION
CLOCKS for
PXI_STAR<0..16> and
PXI_TRIG<0..7>
DDS
÷2N
÷2M
3
PXI_CLK10
Figure 3-3. High-Level Schematic of NI PXIe-6672 Signal Routing Architecture
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Figure 3-4 provides a more detailed view of the Selection Circuitry
referenced in Figure 3-3.
CLKIN*
PFI<0..5>
PXI_TRIG<0..7>
PXI_STAR<0..16>
Software Trigger
GND
CLK
CLK/N
CLK/M
* CLKIN only valid for PXI_STAR
Figure 3-4. Signal Selection Circuitry Diagram
Determining Sources and Destinations
All signal routing operations can be characterized by a source (input) and
a destination. In addition, synchronous routing operations must also define
a third signal known as the synchronization clock. Refer to the Choosing
the Type of Routing section for more information on synchronous versus
asynchronous routing.
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Table 3-4 summarizes the sources and destinations of the NI PXIe-6672.
The destinations are listed in the horizontal heading row, and the sources
are listed in the column at the far left. A ✓ in a cell indicates that the source
and destination combination defined by that cell is a valid routing
combination.
Table 3-4. Sources and Destinations for NI PXIe-6672 Signal Routing Operations
Destinations
Front Panel
Backplane
Onboard
CLKOUT
PFI <0..5>
PXI_
CLK10_IN
PXI_Star
Trigger
<0..16>
PXI TRIG
<0..7>
TCXO
Reference
PLL
*
*
*
CLKIN
✓
✓
✓
✓
✓
✓
✓
PFI <0..5>
PXI_ CLK10
✓
✓
†
†
†
✓
✓
✓
✓
PXI_STAR
<0..16>
✓
✓
✓
PXI TRIG
<0..7>
✓
✓
✓
*
*
*
TCXO
DDS
✓
✓
✓
✓
✓
✓
†
†
†
✓
✓
✓
Global
Software
Trigger
✓
✓
✓
*
Can be accomplished in two stages by routing source to PXI_CLK10_IN, replacing PXI_CLK10 with PXI_CLK10_IN
(occurs automatically in most chassis), and then routing PXI_CLK10 to the destination. The source must be 10 MHz.
†
Routing PXI_CLK10 or DDS to PFI, PXI_Star, or PXI_Trigger is accomplished by setting PXI_CLK10 or DDS to be the
synchronization clock (NI-Sync Property Node) and then routing the synchronization clock as the source.
Using Front Panel PFIs As Inputs
The front-panel PFIs can receive external signals from 0 to +5 V. They can
be terminated programmatically with 50 Ω resistances to match the cable
impedance and minimize reflections.
Note Terminating the signals with a 50 Ω resistance is recommended when the source is
The voltage thresholds for the front-panel PFI inputs are programmable.
The input signal is generated by comparing the input voltage on the
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PFI connectors to the voltage output of software-programmable DACs.
The thresholds for the PFI lines are individually programmable, which is
useful if you are importing signals from multiple sources with different
voltage swings. The front panel PFI inputs can be routed to any PXI_Star
triggers, PXI triggers, or other front panel PFI outputs.
Using Front Panel PFIs As Outputs
The front panel PFI outputs are +3.3 V drivers with 50 Ω output
impedance. The outputs can drive 50 Ω loads, such as a 50 Ω coaxial cable
with a 50 Ω receiver. This cable configuration is the recommended setup to
minimize reflections. With this configuration, the receiver sees a single
+1.6 V step—a +3.3 V step split across the 50 Ω resistors at the source and
the destination.
destination sees a single step to +3.3 V, but the source sees a reflection.
This cable configuration is acceptable for low-frequency signals or short
cables. You can select the signal source from the front panel triggers
(PFI <0..5>), the PXI star triggers, the PXI triggers, or the synchronization
clock (PXI_CLK10, the DDS clock, or PFI 0). The synchronization clock
concept is explained in more detail in the Choosing the Type of Routing
section.
You can independently select the output signal source for each PFI line
from one of the following sources:
•
•
•
•
•
Another PFI <0..5>
PXI triggers <0..7> (PXI_TRIG <0..7>)
PXI_STAR <0..16>
Global software trigger
PFI synchronization clock
The PFI synchronization clock may be any of the following signals:
•
•
•
•
DDS clock
PXI_CLK10
PFI 0 Input
Any of the previously listed signals divided by the first frequency
divider (2n, up to 512)
•
Any of the previously listed signals divided by the second frequency
divider (2m, up to 512)
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Refer to the Choosing the Type of Routing section for more information on
the synchronization clock.
Note The PFI synchronization clock is the same for all routing operations in which
PFI <0..5> is defined as the output, although the divide-down ratio for this clock (full rate,
first divider, second divider) may be chosen on a per route basis.
Using the PXI Triggers
The PXI triggers go to all the slots in the chassis. All modules receive the
same PXI triggers, so PXI trigger 0 is the same for Slot 2 as it is for Slot 3,
and so on. This feature makes the PXI triggers convenient in situations
where you want, for instance, to start an acquisition on several devices at
the same time because all modules will receive the same trigger.
The frequency on the PXI triggers should not exceed 20 MHz to preserve
signal integrity. The signals do not reach each slot at precisely the same
time. A difference of several nanoseconds between slots can occur in an
eight-slot chassis. However, this delay is not a problem for many
applications. You can route signals to the PXI triggers from PFI <0..5>,
from the PXI star triggers, or from other PXI triggers. You also can route
PXI_CLK10 or the DDS clock to a PXI trigger line (PXI_TRIG <0..7>)
using the synchronization clock.
You can independently select the output signal source for each PXI trigger
line from one of the following sources:
•
•
•
•
•
PFI <0..5>
Another PXI trigger <0..7> (PXI_TRIG <0..7>)
PXI_STAR <0..16>
Global software trigger
PXI_Trig/PXI_Star synchronization clock
The PXI_Trig/PXI_Star synchronization clock may be any of the following
signals:
•
•
•
•
DDS clock
PXI_CLK10
PFI 0 Input
Any of the previously listed signals divided by the first frequency
•
Any of the previously listed signals divided by the second frequency
divider (2m, up to 512)
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Refer to the Choosing the Type of Routing section for more information
about the synchronization clock.
Note The PXI_Trig/PXI_Star synchronization clock is the same for all routing operations
in which PXI_TRIG <0..7> or PXI_STAR <0..16> is defined as the output, although the
divide-down ratio for this clock (full rate, first divider, second divider) may be chosen on
a per route basis.
Using the PXI Star Triggers
There are up to 17 PXI star triggers per chassis. Each trigger line
is a dedicated connection between the System Timing Slot and one other
slot. The PXI Specification, Revision 2.1, requires that the propagation
delay along each star trigger line be matched to within 1 ns. A typical upper
limit for the skew in most NI PXI chassis is 500 ps. The low skew of the
PXI star trigger bus is useful for applications that require triggers to arrive
at several modules nearly simultaneously.
The star trigger lines are bidirectional, so signals can be sent to System
Timing Slot from a module in another slot or from System Timing Slot to
the other module.
You can independently select the output signal source for each PXI star
trigger line from one of the following sources:
•
•
•
•
•
•
PFI <0..5>
PXI triggers <0..7> (PXI_TRIG <0..7>)
Global software trigger
PXI_Trig/PXI_Star synchronization clock
CLKIN
Refer to the Using the PXI Triggers section for more information on the
PXI_Trig/PXI_Star synchronization clock.
Choosing the Type of Routing
The NI PXIe-6672 routes signals in one of two ways: asynchronously or
synchronously. The following sections describe the two routing types and
the considerations for choosing each type.
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Asynchronous Routing
Asynchronous routing is the most straightforward method of routing
signals. Any asynchronous route can be defined in terms of two signal
locations: a source and a destination. A digital pulse or train comes in on
the source and is propagated to the destination. When the source signal
goes from low to high, this rising edge is transferred to the destination after
a propagation delay through the module. Figure 3-5 illustrates an
asynchronous routing operation.
Propagation Delay
tpd
Trigger Input
Trigger Output
Some delay is always associated with an asynchronous route, and this
delay varies among NI PXIe-6672 modules, depending on variations in
temperature and chassis voltage. Typical delay times in the NI PXIe-6672
for asynchronous routes between various sources and destinations are
given in Appendix A, Specifications.
Asynchronous routing works well if the total system delays are not too long
for the application. Propagation delay could be caused by the following
reasons:
•
•
•
•
Output delay on the source
Propagation delay of the signal across the backplane(s) and cable(s)
Propagation delay of the signal through the NI PXIe-6672
Time for the receiver to recognize the signal
Both the source and the destination of an asynchronous routing operation
on the NI PXIe-6672 can be any of the following lines:
•
•
•
Any front panel PFI pin (PFI <0..5)
Any PXI star trigger line (PXI_STAR <0..16>)
Any PXI trigger line (PXI_TRIG <0..7>)
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Synchronous Routing
A synchronous routing operation is defined in terms of three signal
locations: a source, a destination, and a synchronization clock. A digital
signal comes in on the source and is propagated to the destination after
the edge has been realigned with the synchronization clock.
operation does not directly follow the input after a propagation delay.
Instead, the output waits for the next rising edge of the clock before it
follows the input. Thus, the output is said to be “synchronous” with this
clock.
Figure 3-6 shows a timing diagram that illustrates synchronous routing.
Setup Hold
Time Time
tsetup
thold
Trigger Input
Synchronization
Clock
Clock to Output
Time, tCtoQ
Trigger Output
Figure 3-6. Synchronous Routing Operation
Synchronous routing can send triggers to several places in the same clock
cycle or send the trigger to those same places after a deterministic skew of
a known number of clock cycles. If a signal arrives at two chassis within
the same clock cycle, each NI PXIe-6672 realigns the signal with the
synchronization clock and distributes it to the modules in each chassis at
the same time. Synchronous routing can thus remove uncertainty about
when triggers are received. If the delays through the system are such that
an asynchronous trigger might arrive near the edge of the receiver clock,
the receiver might see the signal in the first clock cycle, or it might see it in
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the second clock cycle. However, by synchronizing the signal, you can
eliminate the ambiguity, and the signal will always be seen in the second
clock cycle.
One useful feature of synchronous routing is that the signal can be
propagated on either the rising or falling edge of the synchronization clock.
In addition, the polarity of the destination signal can be inverted, which is
useful when handling active-low digital signals.
Possible sources for synchronous routing include the following sources:
•
•
•
•
•
Any front panel PFI pin
Any PXI star trigger line (PXI_STAR <0..16>)
Any PXI trigger line (PXI_TRIG <0..7>)
Global software trigger
The synchronization clock itself
Note The possible destinations for a synchronous route are identical to those for an
asynchronous route. The destinations include any front panel PFI pin, any PXI star trigger
line, or any PXI trigger line.
The synchronization clock for a synchronous route can be any of the
following signals:
•
•
•
•
10 MHz PXI backplane clock signal
DDS clock on the NI PXIe-6672
Front panel PFI 0 Input
One of two “divided copies” of any of the previously listed three
signals. The NI PXIe-6672 includes two clock-divider circuits that can
divide the synchronization clock signals by any power of 2 up to 512.
Refer to Figures 3-3 and 3-4 for an illustration of how the NI PXIe-6672
performs synchronous routing operations.
Generating a Single Pulse (Global Software Trigger)
The global software trigger is a single pulse with programmable delay that
is fired on a software command. This signal is always routed synchronously
with a clock. Therefore, asynchronous routing is not supported when the
signal source is the global software trigger.
The software trigger can be delayed by up to 15 clock cycles on a per route
basis. This feature is useful if a single pulse must be sent to several
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destinations with significantly different propagation delays. By delaying
the pulse on the routes with shorter paths, you can compensate for the
propagation delay. An example of such a situation would be when a trigger
pulse must arrive nearly simultaneously at the local backplane and the
backplane of another chassis separated by 50 m of coaxial cable.
Using the PXI_CLK10 PLL
A module in System Timing Slot of a PXI Express chassis can replace the
PXI_CLK10 reference clock. The NI PXIe-6672 offers three options for
this replacement. This section describes each option.
•
The first option is to replace PXI_CLK10 directly with the TCXO
output on the NI PXIe-6672. This oscillator is a more stable and
accurate reference than the native backplane clock.
•
The second option is to route a 10 MHz clock directly from CLKIN on
the front panel to PXI_CLK10_IN, which is the pin on the backplane
that will replace PXI_CLK10. There is a delay through the module, as
well as a distribution delay on the backplane. These delays tend to
be similar for chassis of the same model, so routing the same clock
to a pair of chassis usually matches PXI_CLK10 to within a few
nanoseconds.
•
The third option is to employ the NI PXIe-6672 PLL circuitry for the
TCXO. As in option 1, the output of the TCXO replaces the native
10 MHz signal. However, this scheme also requires an input signal
on CLKIN. This signal must be a stable clock, and its frequency must
be a multiple of 1 MHz (5 MHz or 13 MHz, for example) between
1 MHz and 105 MHz. The PLL feedback circuit generates a voltage
proportional to the phase difference between the reference input on
PXI_CLK10 and the output of the TCXO. This PLL voltage output
then tunes the output frequency of the TCXO. As long as the incoming
signal is a stable 1 MHz frequency multiple, the PLL circuit quickly
locks the TCXO to the reference, eliminating all phase drift between
the two signals.
Using the PLL provides several advantages over the other two options for
replacing the PXI backplane clock:
•
CLKIN is not required to be 10 MHz. If you have a stable reference
that is a multiple of 1 MHz, such as 13 or 5 MHz, you can
frequency-lock the chassis to it.
•
If CLKIN stops or becomes disconnected, PXI_CLK10 is still present
in the chassis.
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•
If CLKIN is 10 MHz, the NI PXIe-6672 can compensate for
distribution delays in the backplane. The feedback in the PLL comes
from PXI_CLK10. This PLL makes it possible for the NI PXIe-6672
to align clock edges at CLKIN with the edges of PXI_CLK10 that the
modules receive. If you split an external (accurate) 10 MHz reference
and route it to two chassis, they can both lock to it. The result is a
tighter synchronization of PXI_CLK10 on the chassis.
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4
Calibration
This chapter discusses the calibration of the NI PXIe-6672.
Calibration consists of verifying the measurement accuracy of a device
and correcting for any measurement error. The NI PXIe-6672 is factory
calibrated before shipment at approximately 25 °C to the levels indicated
in Appendix A, Specifications. The associated calibration constants—the
corrections that were needed to meet specifications—are stored in the
onboard nonvolatile memory (EEPROM). The driver software uses these
stored values.
Factory Calibration
The factory calibration of the NI PXIe-6672 involves calculating and
storing four calibration constants. These values control the accuracy of
TCXO Frequency
PXI_CLK10 Phase
The TCXO frequency can be varied over a small range. The output
frequency of the TCXO is adjusted using this constant to meet the
specification listed in Appendix A, Specifications. This calibration
applies only to the NI PXIe-6672.
When using the PLL to lock PXI_CLK10 to an external reference clock, the
phase between the clocks can be adjusted. The time between rising edges
of PXI_CLK10 and the input clock is minimized using this constant.
DDS Start Trigger Phase
To start the DDS reliably, the DDS start trigger must arrive within a certain
window of time. The phase of the DDS start trigger is controlled by this
constant to meet the setup and hold-time requirements of the DDS.
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Calibration
DDS Initial Phase
The phase of the DDS output is adjusted using this constant so that the
DDS outputs from multiple NI PXIe-6672 modules are aligned.
Additional Information
Refer to ni.com/calibration for additional information on
NI calibration services.
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A
Specifications
CLKIN Characteristics
CLKIN fundamental
frequency range1 .................................... 1 MHz to 105 MHz,
sine or square wave
Input impedance..................................... 50 Ω, nominal
Input coupling ........................................ AC
Voltage range
DC................................................... 20 V
AC................................................... 400 mVp-p to 5 Vp-p
Absolute maximum input voltage2......... 26 V, max
CLKIN to PXI_CLK10_IN delay
without PLL ........................................... 14 ns to 14.7 ns, typical
CLKIN to PXI_CLK10 delay
with PLL ................................................ 1 ns, max
CLKIN frequency accuracy requirement
For PLL and TCXO ........................ 5.0 ppm
For replacing PXI_CLK10
(no PLL).......................................... 100 ppm3
1
2
CLKIN fundamental frequency can be any multiple of 1 MHz within the range specified when the PLL is engaged and
PXI_CLK10 is locking to it. The frequency must be 10 MHz when replacing PXI_CLK10 without the PLL.
Stresses beyond those listed can cause permanent damage to the device. Exposure to absolute maximum rated conditions for
extended periods of time can affect device reliability. Functional operation of the device outside the conditions indicated in
the operational parts of the specification is not implied.
3
This is a requirement of the PXI specification.
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Appendix A
Specifications
Jitter added to CLKIN
Without PLL....................................0.5 psrms, 10 Hz to 100 kHz,
typical
With PLL.........................................0.6 psrms, 10 Hz to 100 kHz,
typical
Duty cycle distortion of CLKIN to
PXI_CLK10_IN without PLL ................ 1%, max
Required input duty cycle
when using PLL......................................45 to 55%
CLKOUT Characteristics
Output frequency
From PXI_CLK10...........................10 MHz
From TCXO.....................................10 MHz
From DDS .......................................1 MHz1 to 105 MHz
Duty cycle...............................................43 to 55%2
Output impedance...................................50 Ω, nominal
Output coupling ......................................AC
Amplitude, software configurable to two voltage levels
(low and high drive)
Open Load
Low Drive
High Drive
Square Wave
2.0 Vp-p, typical
5.0 Vp-p, typical
50 Ω Load
Low Drive
High Drive
Square Wave
1.0 Vp-p, typical
2.5 Vp-p, typical
1
2
The lower limit is load dependent because of the AC coupling. This limit is less than 1 MHz for high-impedance loads.
The duty cycle specification covers both DDS range and TCXO.
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Specifications
Square wave rise/fall time (10 to 90%)
Low drive........................................ 0.5 ns min,
2.5 ns max
High drive ....................................... 0.5 ns min,
2.5 ns max
PFI <0..5>
Input Characteristics
Frequency range..................................... DC to 105 MHz
Input impedance..................................... 50 Ω, nominal, or 1 kΩ 10%,
|| 35 pF, software-selectable
Input coupling ........................................ DC
Voltage level .......................................... 0 to 5 V
Absolute maximum input voltage1......... 5.25 V, max
Input threshold
Voltage level................................... 0 to 4.3 V, software-selectable
Voltage resolution........................... 16.8 mV (8 bits)
Error................................................ 40 mV
Hysteresis............................................... 50 mV
Asynchronous delay, tpd
PFI <0..5> to
PXI_TRIG <0..7> output................ 19 to 26 ns, typical
PFI <0..5> to
PXI_STAR <0..12> output............. 10 to 19 ns, typical
Synchronized trigger
input setup time, tsetup2 ........................... 16.5 ns, typical
Synchronized trigger
1
Stresses beyond those listed can cause permanent damage to the device. Exposure to absolute maximum rated conditions for
extended periods of time can affect device reliability. Functional operation of the device outside the conditions indicated in
the operational parts of the specifications is not implied.
2
Relative to PXI_CLK10 at the backplane connector. When PLL is used to route CLKIN to PXI_CLK10_IN, CLKIN and
PXI_CLK10 are phase locked with 1 ns max phase difference. Refer to the Synchronous Routing section of Chapter 3,
Hardware Overview, for more details.
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Specifications
Output Characteristics
Frequency range .....................................DC to 105 MHz
Output impedance...................................50 Ω, nominal
Output coupling ......................................DC
Voltage level...........................................0 to 1.6 V into 50 Ω;
0 to 3.3 V into open circuit,
typical
Absolute maximum applied voltage1...... 5.25 V, max
PXI_CLK10 synchronized trigger clock
to out time, tCtoQ2 ....................................10.7 ns, typical
Output-to-output skew, synchronous......500 ps, typical
PXI_STAR Trigger Characteristics
PXI_STAR <0..16> to
PXI_STAR <0..16> output skew
at NI PXIe-6672 backplane connector....300 ps3, typical
Asynchronous delays, tpd
PXI_STAR <0..16> to
PFI <0..5> output.............................13 to 17 ns, typical
PXI_STAR <0..16> to
PXI_TRIG <0..7> output.................18 to 24 ns, typical
1
Stresses beyond those listed can cause permanent damage to the device. Exposure to absolute maximum rated conditions for
extended periods of time can affect device reliability. Functional operation of the device outside the conditions indicated in
the operational parts of the specifications is not implied.
2
3
Relative to PXI_CLK10 at backplane connector.
This specification applies to all synchronous routes to the PXI_Star lines, as well as asynchronous routes from the PFI inputs
to the PXI_Star lines.
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PXI Trigger Characteristics
PXI_TRIG <0..7> to
PXI_TRIG <0..7> output skew
at NI PXIe-6672 backplane connector... 5 ns, typical
Asynchronous delay, tpd
PXI_TRIG <0..7> to
PFI <0..5> output............................ 15 to 22 ns, typical
TCXO Characteristics
Frequency............................................... 10 MHz
Initial accuracy....................................... 2.5 ppm
Long-term stability (1 year)1.................. 1 ppm
Temperature stability (0 to 55 °C)2........ 2 ppm
DDS Characteristics
Frequency range..................................... 1 Hz to 105 MHz
Frequency resolution.............................. < 0.075 Hz
Frequency accuracy................................ Equivalent to PXI_CLK10
accuracy3
Physical
Chassis requirement ............................... One 3U PXI Express
System Timing Slot
Front panel connectors........................... SMB male, 50 Ω
Front panel indicators............................. Two tricolor LEDs
(green, red, and amber)
1
Includes stability of TCXO and supporting circuitry.
2
3
Includes temperature stability of TCXO and supporting circuitry.
The DDS frequency inherits the relative frequency of PXI_CLK10. For example, if you route the TCXO to PXI_CLK10,
the DDS output inherits the same relative frequency accuracy as the TCXO output.
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Appendix A
Specifications
Recommended maximum cable length1
PFI/CLKOUT, DC to 10 MHz........200 m
CLKOUT High Gain, 105 MHz......80 m2
PFI/CLKOUT Low Gain,
105 MHz..........................................30 m3
Weight ....................................................0.459 lb (208 g)
Power Requirements
+3.3 V .....................................................800 mA, max
+12 V ......................................................700 mA, max
Environment
Maximum altitude...................................2,000 m (800 mbar)
(at 25 °C ambient temperature)
Pollution Degree.....................................2
Indoor use only.
Caution When required, clean the NI PXIe-6672 with a soft nonmetallic brush. Make sure
that the device is completely dry and free from contaminants before returning it to service.
Operating Environment
Ambient temperature range ....................0 to 55 °C (Tested in accordance
with IEC-60068-2-1 and
IEC-60068-2-2. Meets
MIL-PRF-28800F Class 3
low temperature limit and
MIL-PRF-28800F Class 2
high temperature limit.)
Relative humidity range..........................10% to 90%, noncondensing
(Tested in accordance with
IEC-60068-2-56.)
1
Cable length measurements were made with an RG 58 cable. Maximum cable length performance will vary depending on the
cable type used.
2
3
Maximum cable length with a direct cable connection. Loss from a signal splitter would reduce maximum cable length.
Maximum cable length with a direct cable connection. Loss from a signal splitter would reduce maximum cable length.
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Appendix A
Specifications
Storage Environment
Ambient temperature range.................... –40 to 71 °C (Tested in
accordance with IEC-60068-2-1
and IEC-60068-2-2. Meets
MIL-PRF-28800F Class 3
low temperature limit.)
Relative humidity range......................... 5% to 95% noncondensing
(Tested in accordance with
IEC-60068-2-56.)
Shock and Vibration
Operational shock .................................. 30 g peak, half-sine, 11 ms pulse
(Tested in accordance with
IEC-60068-2-27. Meets
MIL-PRF-28800F Class 2 limits.)
Random vibration
Operating ........................................ 5 to 500 Hz, 0.3 grms
Nonoperating .................................. 5 to 500 Hz, 2.4 grms
(Tested in accordance with
IEC-60068-2-64. Nonoperating
test profile exceeds the
requirements of
MIL-PRF-28800F, Class 3.)
Note Specifications are subject to change without notice.
Safety
This product is designed to meet the requirements of the following
standards of safety for electrical equipment for measurement, control, and
laboratory use:
•
•
• IEC 61010-1, EN 61010-1
• UL 61010-1, CSA 61010-1
Note For UL and other safety certifications, refer to the product label or visit ni.com/
certification, search by model number or product line, and click the appropriate link
in the Certification column.
© National Instruments Corporation
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Appendix A
Specifications
Electromagnetic Compatibility
This product is designed to meet the requirements of the following
standards of EMC for electrical equipment for measurement, control, and
laboratory use:
•
•
•
EN 61326 EMC requirements; Minimum Immunity
EN 55011 Emissions; Group 1, Class A
CE, C-Tick, ICES, and FCC Part 15 Emissions; Class A
Note For EMC compliance, operate this device according to printed documentation.
CE Compliance
This product meets the essential requirements of applicable European
Directives, as amended for CE marking, as follows:
•
•
2006/95/EC; Low-Voltage Directive (safety)
2004/108/EC; Electromagnetic Compatibility Directive (EMC)
Note 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.
Environmental Management
National Instruments is committed to designing and manufacturing
products in an environmentally responsible manner. NI recognizes that
eliminating certain hazardous substances from our products is beneficial
not only to the environment but also to NI customers.
For additional environmental information, refer to the NI and the
Environment Web page at ni.com/environment. This page contains the
environmental regulations and directives with which NI complies, as well
as other environmental information not included in this document.
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Appendix A
Specifications
Waste Electrical and Electronic Equipment (WEEE)
EU Customers At the end of their life cycle, all products must be sent to a WEEE recycling
center. For more information about WEEE recycling centers and National Instruments
WEEE initiatives, visit ni.com/environment/weee.htm.
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National Instruments
National Instruments
(RoHS)
Ё
ড়㾘ᗻֵᙃˈ䇋ⱏᔩ ni.com/environment/rohs_chinaDŽ
RoHS
ni.com/environment/rohs_china
(For information about China RoHS compliance, go to
.)
© National Instruments Corporation
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NI PXIe-6672 User Manual
B
Technical Support and
Professional Services
Visit the following sections of the award-winning National Instruments
Web site at ni.com for technical support and professional services:
•
Support—Technical support resources at ni.com/support include
the following:
–
Self-Help Technical Resources—For answers and solutions,
visit ni.com/support for software drivers and updates, a
searchable KnowledgeBase, product manuals, step-by-step
troubleshooting wizards, thousands of example programs,
tutorials, application notes, instrument drivers, and so on.
Registered users also receive access to the NI Discussion Forums
at ni.com/forums. NI Applications Engineers make sure every
question submitted online receives an answer.
–
Standard Service Program Membership—This program
entitles members to direct access to NI Applications Engineers
via phone and email for one-to-one technical support as well as
exclusive access to on demand training modules via the Services
Resource Center. NI offers complementary membership for a full
year after purchase, after which you may renew to continue your
benefits.
For information about other technical support options in your
area, visit ni.com/services, or contact your local office at
ni.com/contact.
•
•
Training and Certification—Visit ni.com/training for
self-paced training, eLearning virtual classrooms, interactive CDs,
and Certification program information. You also can register for
instructor-led, hands-on courses at locations around the world.
System Integration—If you have time constraints, limited in-house
technical resources, or other project challenges, National Instruments
Alliance Partner members can help. To learn more, call your local
NI office or visit ni.com/alliance.
© National Instruments Corporation
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NI PXIe-6672 User Manual
Appendix B
Technical Support and Professional Services
•
Declaration of Conformity (DoC)—A DoC is our claim of
compliance with the Council of the European Communities using
the manufacturer’s declaration of conformity. This system affords
the user protection for electromagnetic compatibility (EMC) and
product safety. You can obtain the DoC for your product by visiting
ni.com/certification.
•
Calibration Certificate—If your product supports calibration,
you can obtain the calibration certificate for your product at
ni.com/calibration.
If you searched ni.com and could not find the answers you need, contact
your local office or NI corporate headquarters. Phone numbers for our
worldwide offices are listed at the front of this manual. You also can visit
the Worldwide Offices section of ni.com/niglobal to access the branch
office Web sites, which provide up-to-date contact information, support
phone numbers, email addresses, and current events.
NI PXIe-6672 User Manual
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Glossary
Symbol
Prefix
pico
Value
10–12
10–9
10– 6
10–3
103
p
n
nano
micro
milli
kilo
µ
m
k
M
mega
106
Symbols
%
percent
plus or minus
positive of, or plus
negative of, or minus
per
+
–
/
°
degree
Ω
ohm
A
accumulator
A part where numbers are totaled or stored.
application development environment
ADE
asynchronous
A property of an event that occurs at an arbitrary time, without
synchronization to a reference clock.
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Glossary
B
backplane
An assembly, typically a printed circuit board (PCB), with connectors and
signal paths that bus the connector pins.
bus
The group of conductors that interconnect individual circuitry in a
computer. Typically, a bus is the expansion vehicle to which I/O or other
devices are connected. An example of a PC bus is the PCI bus.
C
C
Celsius
CLKIN
CLKIN is a signal connected to the SMB input pin of the same name.
CLKIN can serve as PXI_CLK10_IN or be used as a phase lock reference
for the OCXO.
CLKOUT
clock
CLKOUT is the signal on the SMB output pin of the same name. Either
the OCXO clock or PXI_CLK10 can be routed to CLKOUT.
Hardware component that controls timing for reading from or writing to
groups.
CompactPCI
A Eurocard configuration of the PCI bus for industrial applications.
D
D/A
digital-to-analog
DAC
digital-to-analog converter—an electronic device that converts a digital
number into a corresponding analog voltage or current.
DAQ
Data acquisition—(1) collecting and measuring electrical signals from
sensors, transducers, and test probes or fixtures and inputting them to a
computer for processing; (2) collecting and measuring the same kinds of
electrical signals with A/D and/or DIO devices plugged into a computer,
and possibly generating control signals with D/A and/or DIO devices in the
same computer.
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Glossary
DC
direct current
DDS
direct digital synthesis—a method of creating a clock with a programmable
frequency.
E
EEPROM
electrically erasable programmable read-only memory—ROM that can be
erased with an electrical signal and reprogrammed.
ESD
electrostatic discharge
F
frequency
The basic unit of rate, measured in events or oscillations per second using
a frequency counter or spectrum analyzer. Frequency is the reciprocal of
the period of a signal.
frequency tuning word
front panel
A number that specifies the frequency.
The physical front panel of an instrument or other hardware .
H
Hz
hertz—the number of scans read or updates written per second.
I
in.
inch or inches
J
jitter
The rapid variation of a clock or sampling frequency from an ideal constant
frequency.
© National Instruments Corporation
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Glossary
L
LabVIEW
A graphical programming language.
LED
light-emitting diode—a semiconductor light source.
M
master
The requesting or controlling device in a master/slave configuration.
Measurement &
Automation Explorer
(MAX)
A controlled centralized configuration environment that allows you to
configure all of your National Instruments DAQ, GPIB, IMAQ, IVI,
Motion, VISA, and VXI devices.
N
NI-DAQ
National Instruments driver software for DAQ hardware.
O
oscillator
A device that generates a fixed frequency signal. An oscillator most often
generates signals by using oscillating crystals, but also may use tuned
networks, lasers, or atomic clock sources. The most important
specifications on oscillators are frequency accuracy, frequency stability,
and phase noise.
output impedance
The measured resistance and capacitance between the output terminals of
a circuit
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Glossary
P
PCI
peripheral component interconnect—a high-performance expansion bus
architecture originally developed by Intel to replace ISA and EISA. It is
achieving widespread acceptance as a standard for PCs and work-stations;
it offers a theoretical maximum transfer rate of 132 Mbytes/s.
PCI Express
peripheral component interconnect express—a high-performance
expansion bus architecture that expands on and doubles the data transfer
rates of original PCI. PCI Express is a two-way, serial connection that
carries data in packets along two pairs of point-to-point data lanes,
compared to the single parallel data bus of traditional PCI that routes data
at a set rate. Initial bit rates for PCI Express reach 2.5Gb/s per lane
direction, which equate to data transfer rates of approximately
200 Mbytes/s.
PFI
programmable function interface
phase-locked loop
PLL
precision
The measure of the stability of an instrument and its capability to give the
same measurement over and over again for the same input signal.
propagation delay
PXI
The amount of time required for a signal to pass through a circuit.
A rugged, open system for modular instrumentation based on CompactPCI,
with special mechanical, electrical, and software features. The PXIbus
standard was originally developed by National Instruments in 1997, and
is now managed by the PXIbus Systems Alliance.
PXI Express
An open system for modular instrumentation based on PXI and
CompactPCI Express. PXI Express enhances system timing and software
frameworks while preserving backward compatibility with PXI. The
system controller slot is capable of supporting up to a x16 PCI Express link,
plus a x8 link, providing a total of 6 GB/s bandwidth to the PXI backplane,
which is more than 45 times improvement upon PXI backplane throughput
PXI star
A special set of trigger lines in the PXI backplane for high-accuracy device
synchronization with minimal latencies on each PXI slot.
PXI_Trig/PXI_Star
synchronization clock
The clock signal that is used to synchronize the PXI triggers or PXI_STAR
triggers on an NI PXIe-6672.
© National Instruments Corporation
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Glossary
S
s
seconds
skew
The actual time difference between two events that would ideally occur
simultaneously. Inter-channel skew is an example of the time differences
introduced by different characteristics of multiple channels. Skew can
occur between channels on one module, or between channels on separate
modules (intermodule skew).
slave
slot
A computer or peripheral device controlled by another computer.
The place in the computer or chassis in which a card or module can be
installed.
SMB
sub miniature type B—a small coaxial signal connector that features a snap
coupling for fast connection.
synchronous
A property of an event that is synchronized to a reference clock.
T
tCtoQ
thold
tpd
clock to output time
hold time
propagation delay time
trigger signal
TRIG
trigger
A digital signal that starts or times a hardware event (for example, starting
a data acquisition operation).
tsetup
setup time
V
V
volts
VI
virtual instrument
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Index
description, 3-5
A
Access LED
location (diagram), 3-3
signal description (table), 3-6
color explanation (table), 3-4
overview, 3-4
Active LED
color explanation (table), 3-4
overview, 3-4
asynchronous routing
overview, 3-16
DDS, 3-7
overview, 3-7
PXI_CLK10 and TCXO, 3-8
color
Access LED color explanation (table), 3-4
Active LED color explanation (table), 3-4
configuring the device
Access LED, 3-4
Active LED, 3-4
overview, 2-2
conventions used in the manual, vii
timing diagram, 3-16
B
block diagram
routing architecture, 3-10
signal selection circuitry, 3-11
C
cable configuration, 3-13
calibration
clock, 3-14
additional information, 4-2
DDS initial phase, 4-2
DDS start trigger phase, 4-1
factory calibration, 4-1
PXI_CLK10 phase, 4-1
TCXO frequency, 4-1
front panel triggers as outputs, 3-13
signal description (table), 3-6
DDS initial phase calibration, 4-2
DDS start trigger phase calibration, 4-1
Declaration of Conformity (NI resources), B-2
destinations, possible destinations (table), 3-12
diagnostic tools (NI resources), B-1
direct digital synthesis. See DDS
calibration certificate (NI resources), B-2
CE compliance, specifications, A-8
changing the Active LED color (tip), 3-4
CLKIN connector
description, 3-5
location (diagram), 3-3
specifications, A-1
© National Instruments Corporation
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Index
documentation
global software trigger
conventions used in manual, vii
NI resources, B-1
drivers (NI resources), B-1
generating a single pulse, 3-18
using front panel PFIs as outputs, 3-13
E
H
equipment, getting started, 1-1
examples (NI resources), B-1
block diagram, 3-2
calibration, 4-1
configuring, 2-2
connector descriptions, 3-5
installing, 2-1
F
frequency tuning word, 3-7
front panel
overview, 3-5
See also CLKIN connector; CLKOUT
connector; PFI synchronization clock;
PFI
I
installation
category, 1-4
software, 2-1
instrument drivers (NI resources), B-1
G
generating a clock
DDS, 3-7
overview, 3-7
PXI_CLK10 and TCXO, 3-8
generating a single pulse (trigger), 3-18
getting started
LED
configuring the device, 2-2
equipment, 1-1
Active LED, 3-4
light-emitting diode. See LED
installing the hardware, 2-1
installing the software, 2-1
software programming choices, 1-2
unpacking, 1-2
M
maximum signal rating (caution), 3-5
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N
services, B-1
programming examples (NI resources), B-1
outputs, 3-13
PXI trigger bus. See PXI_TRIG <0..7>
PXI triggers
front panel triggers as outputs, 3-13
PXI_CLK10
NI PXI-6653, parts locator diagram, 3-3
NI PXI-665x
configuration, 2-2
connectors, 3-5
functional overview, 3-5
installation
software, 2-1
Active LED, 3-4
clock generation, 3-8
NI support and services, B-1
DDS phase-lock, 3-6
front panel triggers as outputs, 3-13
using front panel PFIs as outputs, 3-13
using the PXI triggers, 3-14
using the PXI_CLK10 PLL, 3-19
PXI_CLK10 and TCXO, 3-8
PXI_CLK10 phase
O
P
PFI
calibration, 4-1
PFI <0..5> connector
PXI_CLK10_IN
description, 3-5
routing from the CLKIN connector, 3-5
signal description (table), 3-6
PXI_CLK10_OUT
location (diagram), 3-3
signal description (table), 3-6
PFI <0..5> signals
signal description (table), 3-6
PXI_STAR <0..12>
asynchronous routing, 3-16
front panel PFIs as inputs, 3-12
front panel triggers as outputs, 3-13
specifications, A-3
asynchronous routing, 3-16
signal description (table), 3-6
specifications, A-4
using front panel PFIs as inputs, 3-12
using front panel PFIs as outputs, 3-13
PFI synchronization clock
possible sources, 3-13
using front panel PFIs as outputs, 3-13
phase-locked loop. See PLL
physical specifications, A-5
PLL
using front panel PFIs as outputs, 3-13
using the PXI star triggers, 3-15
using the PXI triggers, 3-14
PXI_TRIG <0..7>
asynchronous routing, 3-16
signal description (table), 3-6
specifications, A-5
using front panel PFIs as outputs, 3-13
using the PXI star triggers, 3-15
using the PXI triggers, 3-14
Active LED, 3-4
routing from the CLKIN connector, 3-5
using the PXI_CLK10 PLL, 3-19
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Index
PXI_Trig/PXI_Star synchronization clock
possible sources, 3-14
specifications
CE compliance, A-8
using the PXI triggers, 3-14
CLKIN characteristics, A-1
CLKOUT characteristics, A-2
DDS characteristics, A-5
electromagnetic compatibility, A-8
operating environment, A-6
PFI <0..5>
R
reflections, recommended cable
configuration, 3-13
related documentation, viii
resistors, terminating signals (note), 3-12
routing architecture (figure), 3-10
routing signals
input characteristics, A-3
output characteristics, A-4
physical, A-5
power requirements, A-6
PXI trigger characteristics, A-5
PXI_STAR trigger characteristics, A-4
safety, A-7
front panel triggers
generating a single pulse (trigger), 3-18
possible sources and destinations
(table), 3-12
PXI star triggers, 3-15
PXI triggers, 3-14
types
shock and vibration, A-7
storage environment, A-7
TCXO characteristics, A-5
star triggers. See PXI_STAR <0..12>
support, technical, B-1
See also PXI_Trig/PXI_Star
synchronization clock; PFI
synchronization clock
overview, 3-17
synchronous routing
S
safety specifications, A-7
shock and vibration specifications, A-7
signal descriptions (table), 3-6
signal selection circuitry (figure), 3-11
signal source, 3-11
overview, 3-17
possible sources and destinations, 3-18
synchronization clock sources, 3-18
timing diagram, 3-17
possible sources (table), 3-12
single pulse generation, 3-18
software
installing, 2-1
NI resources, B-1
source
clock generation, 3-8
frequency calibration, 4-1
overview, 3-8
specifications, A-5
technical support, B-1
possible sources (table), 3-12
signal, 3-11
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Index
TCXO
terminating signals with resistors (note), 3-12
threshold, voltage, 3-12
voltage thresholds, programming, 3-12
trigger bus. See PXI_TRIG <0..7>
troubleshooting (NI resources), B-1
Web resources, B-1
U
unpacking the device, 1-2
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