SCXI-1120/D User Manual

SCXI
™
SCXI-1120/D User Manual
Eight-Channel Isolated Analog Input Module and
Eight-Channel Wide Band Isolated Analog Input Module
for Signal Conditioning
SCXI-1120/D User Manual
September 1999 Edition
Part Number 320425D-01
Worldwide Technical Support and Product Information
www.natinst.com
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For further support information, see the Technical Support Resources appendix. To comment on the
documentation, send e-mail to [email protected].
© Copyright 1992, 1999 National Instruments Corporation. All rights reserved.
Important Information
Warranty
The SCXI-1120 and SCXI-1120D are warranted against defects in materials and workmanship for a period of one year from
the date of shipment, as evidenced by receipts or other documentation. National Instruments will, at its option, repair or replace
equipment that proves to be defective during the warranty period. This warranty includes parts and labor.
The media on which you receive National Instruments software are warranted not to fail to execute programming instructions,
due to defects in materials and workmanship, for a period of 90 days from date of shipment, as evidenced by receipts or other
documentation. National Instruments will, at its option, repair or replace software media that do not execute programming
instructions if National Instruments receives notice of such defects during the warranty period. National Instruments does not
warrant that the operation of the software shall be uninterrupted or error free.
A Return Material Authorization (RMA) number must be obtained from the factory and clearly marked on the outside of
the package before any equipment will be accepted for warranty work. National Instruments will pay the shipping costs of
returning to the owner parts which are covered by warranty.
National Instruments believes that the information in this document is accurate. The document has been carefully reviewed
for technical accuracy. In the event that technical or typographical errors exist, National Instruments reserves the right to
make changes to subsequent editions of this document without prior notice to holders of this edition. The reader should consult
National Instruments if errors are suspected. In no event shall National Instruments be liable for any damages arising out of
or related to this document or the information contained in it.
EXCEPT AS SPECIFIED HEREIN, NATIONAL INSTRUMENTS MAKES NO WARRANTIES, EXPRESS OR IMPLIED, AND SPECIFICALLY DISCLAIMS ANY
WARRANTY OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE. CUSTOMER’S RIGHT TO RECOVER DAMAGES CAUSED BY FAULT
OR NEGLIGENCE ON THE PART OF NATIONAL INSTRUMENTS SHALL BE LIMITED TO THE AMOUNT THERETOFORE PAID BY THE CUSTOMER.
NATIONAL INSTRUMENTS WILL NOT BE LIABLE FOR DAMAGES RESULTING FROM LOSS OF DATA, PROFITS, USE OF PRODUCTS, OR INCIDENTAL
OR CONSEQUENTIAL DAMAGES, EVEN IF ADVISED OF THE POSSIBILITY THEREOF. This limitation of the liability of National Instruments
will apply regardless of the form of action, whether in contract or tort, including negligence. Any action against National
Instruments must be brought within one year after the cause of action accrues. National Instruments shall not be liable for
any delay in performance due to causes beyond its reasonable control. The warranty provided herein does not cover damages,
defects, malfunctions, or service failures caused by owner’s failure to follow the National Instruments installation, operation,
or maintenance instructions; owner’s modification of the product; owner’s abuse, misuse, or negligent acts; and power failure
or surges, fire, flood, accident, actions of third parties, or other events outside reasonable control.
Copyright
Under the copyright laws, this publication may not be reproduced or transmitted in any form, electronic or mechanical,
including photocopying, recording, storing in an information retrieval system, or translating, in whole or in part, without
the prior written consent of National Instruments Corporation.
Trademarks
ComponentWorks™, CVI™, LabVIEW™, Measure™, natinst.com™, National Instruments™, NI-DAQ™, SCXI™,
and VirtualBench™ are trademarks of National Instruments Corporation.
Product and company names mentioned herein are trademarks or trade names of their respective companies.
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.
Contents
About This Manual
Conventions ...................................................................................................................ix
National Instruments Documentation ............................................................................x
Chapter 1
Introduction
About the SCXI-1120/D ................................................................................................1-1
What You Need to Get Started ......................................................................................1-2
Unpacking ......................................................................................................................1-3
Software Programming Choices ....................................................................................1-3
National Instruments Application Software ....................................................1-3
NI-DAQ Driver Software ................................................................................1-4
Optional Equipment .......................................................................................................1-5
Chapter 2
Configuration and Installation
Module Configuration....................................................................................................2-1
Digital Signal Connections..............................................................................2-4
Using Jumpers W42 and W43 ..........................................................2-5
Using Jumper W44 on Revisions A and B of the SCXI-1120..........2-6
Using Jumper W44 on Revision C of the SCXI-1120 and
All Revisions of the SCXI-1120D .................................................2-6
Analog Configuration......................................................................................2-8
Grounding, Shielding, and Reference-Mode Selection ....................2-8
Direct Temperature Connection........................................................2-10
Gain Jumpers for the SCXI-1120/D..................................................2-10
SCXI-1120 Filter Jumpers ................................................................2-12
SCXI-1120D Filter Jumpers .............................................................2-13
Hardware Installation.....................................................................................................2-14
Chapter 3
Signal Connections
SCXI-1120/D Front Connector......................................................................................3-3
Front Connector Signal Descriptions.............................................................................3-4
Analog Input Channels ....................................................................................3-5
Temperature Sensor Connection .....................................................................3-7
SCXI-1120/D Rear Connector.......................................................................................3-8
© National Instruments Corporation
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SCXI-1120/D User Manual
Contents
Rear Connector Signal Descriptions ............................................................................. 3-9
Analog Output Signal Connections................................................................. 3-10
Chapter 4
Theory of Operation
Functional Overview ..................................................................................................... 4-1
Power-Up State ............................................................................................... 4-2
SCXIbus Connector and Digital Interface..................................................................... 4-3
Digital Control Circuitry ............................................................................................... 4-4
Analog and Timing Circuitry ........................................................................................ 4-5
Analog Input Channels.................................................................................... 4-6
Analog Output Circuitry ................................................................... 4-9
Chapter 5
Calibration
Calibration Equipment Requirements ........................................................................... 5-1
Offset Null Adjust ......................................................................................................... 5-1
Appendix A
Specifications
Appendix B
Technical Support Resources
Glossary
Index
Figures
Figure 1-1.
Figure 2-1.
Figure 2-2.
Figure 3-1.
Figure 3-2.
Figure 3-3.
SCXI-1120/D User Manual
The Relationship between the Programming Environment,
NI-DAQ, and Your Hardware............................................................... 1-5
SCXI-1120/D Parts Locator Diagram................................................... 2-2
Removing the SCXI Module Cover...................................................... 2-4
SCXI-1120/D Front Connector Pin Assignments................................. 3-3
Ground-Referenced Signal Connection for the SCXI-1120/D
with High Common-Mode Voltage ...................................................... 3-5
Floating Signal Connection for the SCXI-1120/D Referenced to
Chassis Ground for Better Signal-to-Noise Ratio................................. 3-5
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Contents
Figure 3-4.
Figure 3-5.
Figure 3-7.
Figure 3-8.
Floating AC-Coupled Signal Connection for the SCXI-1120...............3-6
AC-Coupled Signal Connection for the SCXI-1120 with
High Common-Mode Voltage...............................................................3-6
AC-Coupled Signal Connection for the SCXI-1120D with
High Common Mode Voltage ...............................................................3-7
Floating AC-Coupled Signal Connection for the SCXI-1120D............3-7
SCXI-1120/D Rear Signal Connector Pin Assignments .......................3-8
Figure 4-1.
Figure 4-2.
Figure 4-3.
Figure 4-4.
Figure 4-5.
SCXI-1120/D Block Diagram ...............................................................4-1
Digital Interface Circuitry Block Diagram............................................4-3
SCXI-1120/D Digital Control ...............................................................4-4
Analog Input Block Diagram ................................................................4-6
Analog Output Circuitry........................................................................4-9
Figure 3-6.
Tables
Table 2-1.
Table 2-2.
Table 2-3.
Table 2-4.
Table 2-5.
Table 2-6.
Table 2-7.
Digital Signal Connections, Jumper Settings ........................................2-7
Jumper W46 Settings.............................................................................2-9
Jumper W41 Settings.............................................................................2-10
Gain Jumper Allocation.........................................................................2-10
Gain Jumper Positions...........................................................................2-11
SCXI-1120 Filter Jumper Allocation ....................................................2-12
SCXI-1120D Filter Jumper Allocation .................................................2-13
Table 3-1.
Table 3-2.
Table 3-3.
SCXI-1120/D Front Connector Signal Descriptions.............................3-4
Rear Connector Signal Descriptions .....................................................3-9
SCXIbus to SCXI-1120/D Rear Connector
to DAQ Device Pin Equivalencies ........................................................3-11
Table 5-1.
Calibration Potentiometers Reference Designators...............................5-2
Table A-1.
Table A-2.
Table A-3.
Input Signal Range ................................................................................A-5
System Noise RTI (0.1 Hz to 50 kHz) ..................................................A-6
Switching Supply Noise (approximately at 100 kHz)...........................A-7
© National Instruments Corporation
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SCXI-1120/D User Manual
About This Manual
This manual describes the electrical and mechanical aspects of the
SCXI-1120 and SCXI-1120D (SCXI-1120/D) modules and contains
information concerning their installation and operation.
The SCXI-1120 and SCXI-1120D are National Instruments Signal
Conditioning eXtensions for Instrumentation (SCXI) Series modules.
The SCXI-1120/D provides eight isolated input channels. Each channel
is independently configurable through jumpers.
The SCXI-1120 module is designed for low-cost signal conditioning of
thermocouples, volt sources, millivolt sources, and 4 to 20 mA sources
or 0 to 20 mA process-current sources where high common-mode
voltages exist.
The SCXI-1120D module is designed for low-cost signal conditioning
of volt, millivolt, and current sources that require a 20 kHz bandwidth
and where high common-mode voltages exist.
Conventions
The following conventions appear in this manual:
♦
The ♦ symbol indicates that the following text applies only to a specific
product, a specific operating system, or a specific software version.
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.
italic
Italic text denotes variables, emphasis, a cross reference, or an introduction
to a key concept. This font also denotes text that is a placeholder for a word
or value that you must supply.
Lab/1200
Lab device refers to the Lab-LC, Lab-NB, Lab-PC, Lab-PC+,
Lab-PC-1200, and Lab-PC-1200AI.
PC
PC refers to the IBM PC/XT, the IBM PC AT, and compatible computers.
SCXI-1120
SCXI-1120 refers to only the SCXI-1120 module.
© National Instruments Corporation
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SCXI-1120/D User Manual
About This Manual
SCXI-1120D
SCXI-1120D refers to only the SCXI-1120D module.
SCXI-1120/D
SCXI-1120/D refers to both the SCXI-1120D module and the SCXI-1120
module.
Slot 0
Slot 0 refers to the power supply and control circuitry in the SCXI chassis.
National Instruments Documentation
The SCXI-1120/D User Manual is one piece of the documentation set for
your DAQ system. You could have any of several types of manuals
depending on the hardware and software in your system. Use the manuals
you have as follows:
SCXI-1120/D User Manual
•
Getting Started with SCXI—If you are using SCXI, this is the first
manual you should read. It gives an overview of the SCXI system and
contains the most commonly needed information for the modules,
chassis, and software.
•
Your SCXI hardware user manuals—If you are using SCXI, read these
manuals next for detailed information about signal connections and
module configuration. They also explain in greater detail how the
module works and contain application hints.
•
Your DAQ hardware documentation—This documentation has
detailed information about the DAQ hardware that plugs into or is
connected to your computer. Use this documentation for hardware
installation and configuration instructions, specification information
about your DAQ hardware, and application hints.
•
Software documentation—You may have both application software
and NI-DAQ software documentation. National Instruments
application software includes ComponentWorks, LabVIEW,
LabWindows/CVI, Measure, and VirtualBench. After you set up your
hardware system, use either your application software documentation
or the NI-DAQ documentation to help you write your application. If
you have a large, complicated system, it is worthwhile to look through
the software documentation before you configure your hardware.
•
Accessory installation guides or manuals—If you are using accessory
products, read the terminal block and cable assembly installation
guides. They explain how to physically connect the relevant pieces of
the system. Consult these guides when you are making your
connections.
•
SCXI Chassis Manual—If you are using SCXI, read this manual for
maintenance information on the chassis and installation instructions.
x
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1
Introduction
This chapter describes the SCXI-1120/D; lists what you need to get started;
describes the optional software, optional equipment, and custom cables;
and explains how to unpack the SCXI-1120/D kit.
About the SCXI-1120/D
The SCXI-1120/D has eight isolated input channels. The SCXI-1120 is a
module for signal conditioning of thermocouples, volt sources, millivolt
sources, 4 to 20 mA current sources, and 0 to 20 mA process-current
sources. If external excitation is provided, thermistors, RTDs, and strain
gauges can also be measured. The SCXI-1120D is a module for signal
conditioning and isolating volt sources, millivolt sources, and current
sources that require a bandwidth of up to 20kHz. If you provide external
excitation, you can use strain gauges and other vibration sensors. The
SCXI-1120/D can operate in two output modes—in the parallel-output
mode with all eight input channels connected in parallel to eight DAQ
device channels, or in the multiplexed-output mode with all eight channels
multiplexed into a single DAQ device channel.
The SCXI-1120/D operates with full functionality with the National
Instruments MIO, 1200 Series, and Lab PC+ devices. You can use the
Lab-NB, the Lab-PC, the Lab-LC, and the PC-LPM-16/PnP devices with
the SCXI-1120/D, but these devices cannot scan the module when it is
configured in the multiplexed-output mode. These devices can perform
only single-channel reads in this mode. You can multiplex several
SCXI-1120/D modules into a single channel, thus greatly increasing the
number of analog input signals that can be digitized.
The addition of a shielded terminal block provides screw terminals for easy
signal attachment to the SCXI-1120/D. In addition, a temperature sensor
for cold-junction compensation (CJC) of thermocouples is included on the
terminal block. This cold-junction reference (CJR) is either multiplexed
along with the eight channels or connected by jumpers to a different
channel of the DAQ device.
© National Instruments Corporation
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SCXI-1120/D User Manual
Chapter 1
Introduction
With the SCXI-1120/D, the SCXI chassis can serve as a fast-scanning
signal conditioner for laboratory testing, production testing, and industrial
process monitoring.
Detailed specifications of the SCXI-1120/D are listed in Appendix A,
Specifications.
What You Need to Get Started
To set up and use your SCXI-1120/D, you will need the following items:
❑ SCXI-1120 or SCXI-1120D module
❑ SCXI-1120/D User Manual
❑ One of the following chassis and your SCXI chassis manual:
–
SCXI-1000
–
SCXI-1000DC
–
SCXI-1001
–
SCXI-2000
❑ An SCXI terminal block/connector assembly (optional)
❑ DAQ device or SCXI-1200
❑ Your computer
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Chapter 1
Introduction
Unpacking
Your SCXI-1120/D module is shipped in an antistatic package to prevent
electrostatic damage to the module. Electrostatic discharge can damage
several components on the module. To avoid such damage in handling the
module, take the following precautions:
•
Ground yourself using a grounding strap or by holding a grounded
object.
•
Touch the antistatic package to a metal part of your SCXI chassis
before removing the module from the package.
•
Remove the module from the package and inspect the module for loose
components or any other sign of damage. Notify National Instruments
if the module appears damaged in any way. Do not install a damaged
module into your SCXI chassis.
•
Never touch the exposed pins of connectors.
Software Programming Choices
There are several options to choose from when programming your National
Instruments plug-in DAQ and SCXI hardware. You can use LabVIEW,
LabWindows/CVI, NI-DAQ, ComponentWorks, Measure, VirtualBench,
or register-level programming.
National Instruments Application Software
ComponentWorks contains tools for data acquisition and instrument
control built on NI-DAQ driver software. ComponentWorks provides a
higher-level programming interface for building virtual instruments
through standard OLE controls and DLLs. With ComponentWorks, you
can use all of the configuration tools, resource management utilities, and
interactive control utilities included with NI-DAQ.
LabVIEW features interactive graphics, a state-of-the-art user interface,
and a powerful graphical programming language. The LabVIEW Data
Acquisition VI Library, a series of VIs for using LabVIEW with National
Instruments devices, is included with LabVIEW. The LabVIEW Data
Acquisition VI Library is functionally equivalent to the NI-DAQ software.
© National Instruments Corporation
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SCXI-1120/D User Manual
Chapter 1
Introduction
LabWindows/CVI features interactive graphics, a state-of-the-art user
interface, and uses the ANSI standard C programming language. The
LabWindows/CVI Data Acquisition Library, a series of functions for using
LabWindows/CVI with National Instruments DAQ hardware, is included
with your NI-DAQ software kit. The LabWindows/CVI Data Acquisition
Library is functionally equivalent to the NI-DAQ software.
VirtualBench features virtual instruments (VIs) that combine DAQ
products, software, and your computer to create a stand-alone instrument
with the added benefit of the processing, display, and storage capabilities
of your computer. VirtualBench instruments load and save waveform data
to disk in the same forms that can be used in popular spreadsheet programs
and word processors.
Using ComponentWorks, LabVIEW, LabWindows/CVI, or VirtualBench
software will greatly reduce the development time for your data acquisition
and control application.
NI-DAQ Driver Software
The NI-DAQ driver software is included at no charge with all National
Instruments DAQ hardware. NI-DAQ has an extensive library of functions
that you can call from your application programming environment. These
functions include routines for analog input (A/D conversion), buffered data
acquisition (high-speed A/D conversion), analog output (D/A conversion),
waveform generation, digital I/O, counter/timer operations, SCXI, RTSI,
self-calibration, messaging, and acquiring data to extended memory.
NI-DAQ also internally addresses many of the complex issues between the
computer and the plug-in device, such as programming interrupts and
DMA controllers. NI-DAQ maintains a consistent software interface
among its different versions so that you can change platforms with minimal
modifications to your code. Whether you are using conventional
programming languages, LabVIEW, or LabWindows/CVI, your
application uses the NI-DAQ driver software, as illustrated in Figure 1-1.
SCXI-1120/D User Manual
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Chapter 1
Introduction
Personal
Computer or
Workstation
DAQ or
SCXI Hardware
Virtual Bench
(Windows 95, 3.1)
NI-DAQ
Driver Software
Conventional
Programming Enviroment
(Macintosh, or Sun)
ComponentWorks
(Windows 95, NT)
LabVIEW
(Windows 95, 3.1, NT
Macintosh, or Sun)
LabWindows/CVI
(Windows 95, 3.1, NT,
or Sun)
Figure 1-1. The Relationship between the Programming Environment,
NI-DAQ, and Your Hardware
Optional Equipment
National Instruments offers a variety of products to use with your
SCXI-1120/D, as follows:
•
Cables and cable assemblies, shielded and ribbon
•
Shielded terminal blocks and connector-and-shell assemblies
•
SCXI process current resistor kit
•
SCXI modules and accessories for isolating, amplifying, exciting, and
multiplexing signals for relays and analog output. With SCXI you can
condition and acquire up to 3,072 channels.
For additional information about optional equipment available from
National Instruments refer to your National Instruments catalogue or
call the office nearest you.
© National Instruments Corporation
1-5
SCXI-1120/D User Manual
Configuration and Installation
2
This chapter describes how to configure the SCXI-1120/D jumpers and
how to install the SCXI-1120/D into the SCXI chassis.
Module Configuration
The SCXI-1120/D includes 46 jumpers that are shown in Figure 2-1.
© National Instruments Corporation
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SCXI-1120/D User Manual
Thumbscrew
Input Null
Adjust
Potentiometers
Output Null
Adjust
Potentiometers
Configuration and Installation
Terminal
Block
Mounting
Hole
Chapter 2
SCXI-1120/D User Manual
Product Name,
Assembly Number,
and Serial Number
Second-Stage
Filter Jumpers
Rear
Signal
Connector
Front
Connector
Connector
and Shell
Mounting
Holes
2-2
SCXIbus
Connector
Terminal
Block
Mounting
Hole
Digital
Jumpers
Thumbscrew
FRONT
First-Stage
Gain Jumpers
Grounding
Screw
First-Stage
Filter Jumpers
Second-Stage
Gain Jumpers
Figure 2-1. SCXI-1120/D Parts Locator Diagram
REAR
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Chapter 2
Configuration and Installation
The jumpers are used as follows:
•
Fixed jumpers
–
On Revision A and B SCXI-1120 modules, jumper W42 is unused
and should not be connected.
–
Jumper W45 is reserved and should not be reconfigured.
–
On Revision A and B SCXI-1120 modules, jumper W44 carries
the SLOT0SEL* signal from the rear signal connector, after
buffering, to the SCXIbus INTR* line and should be left in the
SCXI-1120 factory-default position (position 1). On all
SCXI-1120D modules and on Revision C and later SCXI-1120
modules, jumper W44 does not exist.
Note The revision letter is located on the National Instruments label located on the side of
each SCXI-1120/D module. The revision letter is found in the part number and is the letter
found in that part number.
•
© National Instruments Corporation
User-configurable jumpers
–
Jumper W43 carries the SCXIbus MISO line, after buffering, to
the SERDATOUT signal on the rear signal connector.
–
On all SCXI-1120D and on Revision C and later SCXI-1120
modules, jumper 42 connects a pullup resistor to the
SERDATOUT signal on the rear signal connector.
–
Jumper W46 configures the guard, the analog output ground, and
enables the NRSE mode.
–
Jumpers W1 through W8 configure the first-stage gain of channels
0 through 7, respectively.
–
Jumpers W9 through W16 configure the second-stage gain of
channels 0 through 7, respectively.
–
Jumpers W17 through W24 configure the first-stage filtering of
input channels 0 through 7, respectively.
–
Jumpers W25 through W40 configure the second-stage filtering of
input channels 0 through 7, respectively.
–
Jumper W41 directly connects the temperature sensor to the rear
signal connector. To do so, set jumper W46 in the AB-R2 or
AB-R0 position first.
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SCXI-1120/D User Manual
Chapter 2
Configuration and Installation
Tables 2-1 to 2-2 list the description and configuration of the
user-configurable jumpers. To change the configuration of the module,
refer to Figures 2-1 and 2-2 as you perform the following steps:
1.
Remove the grounding screw of the SCXI module top cover.
2.
Snap out the top cover of the shield by placing a screwdriver in the
groove at the bottom of the module and pushing down.
3.
Remove the jumpers you want to change and replace them on the
appropriate pins.
4.
Snap the top cover back in place.
5.
Replace the grounding screw to ensure proper shielding.
You must use software to further configure the module. Refer to your
software manual.
Removable Cover
Grounding
Screw
Top of Module
Front Connector
Figure 2-2. Removing the SCXI Module Cover
Digital Signal Connections
The four digital signal connection jumpers have position 1 marked on the
module. Position 3 is not marked explicitly on the module.
The SCXI-1120/D has three jumpers dedicated for communication
between the DAQ device and the SCXIbus. These jumpers are W42, W43,
and W44.
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Chapter 2
Configuration and Installation
Using Jumpers W42 and W43
Leave jumpers W42 and W 43 in their factory-default settings if any one of
the following applies:
•
The SCXI-1120/D is not cabled to a DAQ device
•
The SCXI-1120/D is cabled to a DAQ device, and the SCXI chassis is
the only SCXI chassis cabled to that DAQ device
•
The SCXI-1120/D is cabled to a DAQ device, and there are multiple
SCXI chassis cabled to that DAQ device with shielded cables
In the factory-default setting, jumper W43 connects, after buffering, the
SCXIbus Master-In-Slave-Out (MISO) line to the SERDATOUT pin of the
rear signal connector. In this setting, along with the proper setting of
jumper W42, the DAQ device can read the SCXI-1120/D Module ID
Register. See Chapter 3, Signal Connections, for the pin equivalencies of
the SCXI-1120/D rear signal connector and the DAQ device I/O connector.
Revisions A and B of the SCXI-1120
On Revision A and B SCXI-1120 modules, jumper W42 is not used. Set
jumper W43 as explained in the cases above, except in the case of a
multichassis ribbon cable system. In a multichassis ribbon cable system
with Revision A and B SCXI-1120 modules cabled to the DAQ device, you
can access the MISO line in only one chassis. Pick one of the chassis that
has the SCXI-1120 cabled to the DAQ device. Set jumper W43 on the
SCXI-1120 to position 1. On the SCXI-1120 modules that are in the other
chassis and cabled to the DAQ device, set jumper W43 to position 3.
Notice that you will only be able to access digital information from the
chassis that has the SCXI-1120 with jumper W43 set to position 1.
Revisions C and Later of the SCXI-1120 and All Revisions of
the SCXI-1120D
Jumper W42 in position 1 connects a 2.2 kΩ pullup resistor to the
SERDATOUT line. Position 3 does not connect the pullup resistor to
the SERDATOUT line.
The SERDATOUT line is driven with an open-collector driver.
(An open-collector driver drives low or goes to a high-impedance state,
relying on a pullup resistor to make the signal line go high.)
© National Instruments Corporation
2-5
SCXI-1120/D User Manual
Chapter 2
Configuration and Installation
When using a single chassis, leave W42 and W43 in position 1 on the
SCXI-1120/D that is connected to the DAQ device. In this setting, the
module drives MISO to SERDATOUT and connects the necessary pullup
resistor to the SERDATOUT line.
When using multiple chassis cabled to your DAQ device with shielded
cables, leave jumper W42 and W43 in position 1 on the SCXI-1120/D
modules that are connected to the DAQ device. In this setting, the module
drives MISO to SERDATOUT and connects the necessary pullup resistor
to the SERDATOUT line. All of the shielded adapters buffer and combine
the SERDATOUT from each chassis to the DAQ device.
When using multiple chassis cabled to your DAQ device with ribbon
cables, leave jumper W43 in position 1 on all of the SCXI-1120/D modules
that are cabled to the DAQ device. Set jumper W42 to position 1 on only
one of the SCXI-1120/D modules cabled to the DAQ device. All the other
SCXI-1120/D modules that are cabled to the DAQ device should have
jumper W42 in position 3. If too many pullup resistors are attached to the
SERDATOUT line, the drivers cannot drive the line low. See Table 2-1 for
the description and configuration of the jumper settings.
Using Jumper W44 on Revisions A and B of the
SCXI-1120
On Revision A and B SCXI-1120 modules, the jumper is in factory-default
position 1, which connects SLOT0SEL* to the SCXIbus INTR* line after
buffering. In this setting, the DAQ device controls the SCXIbus INTR*
line. See Chapter 3, Signal Connections, for the pin equivalences of the
SCXI-1120 rear signal connector and the DAQ device I/O connector.
Note Do not use position 3. It is reserved.
Using Jumper W44 on Revision C of the SCXI-1120
and All Revisions of the SCXI-1120D
On Revision C SCXI-1120 modules and all revisions of the SCXI-1120D
modules, jumper W44 is not loaded, and SLOT0SEL* is always buffered
to the INTR* line.
SCXI-1120/D User Manual
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Chapter 2
Configuration and Installation
Table 2-1. Digital Signal Connections, Jumper Settings
Jumper
W42
W42
Description
Position 1—Connects pullup
to SERDATOUT
(factory-default setting).
Applies only to SCXI-1120
Revisions C or later and all
SCXI-1120D modules.
Position 3—Parking position
(not connected on Revisions A
and B of the SCXI-1120).
Configuration
3
2
1
3
2
1
W43
Position 1—Connects MISO
to SERDATOUT
(factory-default setting).
3
2
1
W43
Position 3—Parking position
3
2
1
© National Instruments Corporation
2-7
SCXI-1120/D User Manual
Chapter 2
Configuration and Installation
Table 2-1. Digital Signal Connections, Jumper Settings (Continued)
Jumper
W44
W45
Description
Configuration
Connects SLOT0SEL* to the
SCXIbus INTR* line after
buffering (factory-default
setting). Applies to Revision A
and B of the SCXI-1120
modules only.
3
2
1
Factory-default setting
3
2
1
Analog Configuration
The SCXI-1120/D has 42 analog configuration jumpers.
Notice that the jumper configurations for each channel are similar; only the
jumper reference designator number changes.
Grounding, Shielding, and Reference-Mode
Selection
Jumper W46
Note The SCXI-1120/D will drive pins 4, 6, 8, 10, 12, 14, 16, and 18 on the rear signal
connector, although the SCXI-1120/D is in multiplexed mode.
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Chapter 2
Configuration and Installation
Table 2-2. Jumper W46 Settings
Description
Configuration
B-R0R1—Factory-default setting
in parking position
AB-R0—Connects the analog
reference to AOGND (pins 1 and 2
of the rear signal connector). Use
with RSE DAQ devices. Do not
use with DIFF (differential) input
DAQ devices.
AB-R1—Connects SCXIbus
guard to the analog reference
AB-R2—Enables the NRSE mode
and connects OUTREF, pin 19, of
the rear signal connector to the
analog reference. Use when
SCXI-1120/D has to operate with
DAQ devices that have NRSE
input. Do not use with DIFF input
DAQ devices.
© National Instruments Corporation
2-9
SCXI-1120/D User Manual
Chapter 2
Configuration and Installation
Direct Temperature Connection
Jumper W41
Table 2-3. Jumper W41 Settings
Description
Configuration
Position 1—Temperature sensor
accessed in MTS mode
(factory-default setting)
Position 3—Temperature sensor
accessed in DTS mode, DAQ device
configured for NRSE or RSE mode.
Can access sensor in parallel with
other eight outputs or scan with other
channels without software
interference. Connects to pin 18 of
the rear signal connector and
corresponds to ACH15 of the MIO
devices or the PC-LPM-16/PnP.
3
2
1
3
2
1
Gain Jumpers for the SCXI-1120/D
Each input channel has two user-configurable gain stages. The first gain
stage provides gains of 1, 10, 50, and 100, and the second stage provides
gains of 1, 2, 5, 10, and 20. Tables 2-4 and 2-5 show how to set up the gain
for each channel.
Table 2-4. Gain Jumper Allocation
SCXI-1120/D User Manual
Input Channel
Number
First Gain
Jumper
Second Gain
Jumper
0
W1
W9
1
W2
W10
2
W3
W11
3
W4
W12
4
W5
W13
5
W6
W14
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Chapter 2
Configuration and Installation
Table 2-4. Gain Jumper Allocation (Continued)
Input Channel
Number
First Gain
Jumper
Second Gain
Jumper
6
W7
W15
7
W8
W16
Notice that the SCXI-1120D has an additional fixed pre-stage gain of 0.5.
The SCXI-1120 is shipped with the first-stage gain set to 100 (position A),
and a second-stage gain set to 10 (position D). The SCXI-1120D is shipped
with the first-stage gain set to 100 (position A), and the second-stage gain
set to 20 (position E). To change the gain of your module, move the
appropriate jumper on your module to the position indicated in Tables 2-3
and 2-4. Refer to Figure 2-1 for jumper locations on your module.
To determine the overall gain of a given channel on the SCXI-1120 use the
following formula:
Overall Gain = First-Stage Gain × Second-Stage Gain
To determine the overall gain of a given channel on the SCXI-1120D use
the following formula:
1
Overall Gain = --- × First-Stage Gain × Second-Stage Gain
2
Table 2-5. Gain Jumper Positions
Gain
Setting
Jumper Position
1
D
10
C
50
B
100
A (factory-default setting)
First-stage
© National Instruments Corporation
2-11
SCXI-1120/D User Manual
Chapter 2
Configuration and Installation
Table 2-5. Gain Jumper Positions (Continued)
Gain
Setting
Jumper Position
Second-stage
1
A
2
B
5
C
10
D (factory-default setting
for the SCXI-1120)
20
E (factory-default setting
for the SCXI-1120D)
SCXI-1120 Filter Jumpers
Two-stage filtering is also available on your SCXI-1120 module. The first
stage is located in the isolated section of the input channel, whereas the
second stage is located in the nonisolated section of your input channel.
Two-stage filtering eliminates the noise generated by the isolation
amplifier, producing a higher signal-to-noise ratio. Furthermore, two filter
bandwidths are available, 10 kHz and 4 Hz.
Table 2-6. SCXI-1120 Filter Jumper Allocation
First
Filter Jumper
SCXI-1120/D User Manual
Input
Channel
Number
4 Hz
(Factory
Default)
0
Second
Filter Jumper
10 kHz
4 Hz
(Factory
Default)
10 kHz
W17-A
W17-B
W25
W26
1
W18-A
W18-B
W27
W28
2
W19-A
W19-B
W29
W30
3
W20-A
W20-B
W31
W32
4
W21-A
W21-B
W33
W34
5
W22-A
W22-B
W35
W36
6
W23-A
W23-B
W37
W38
7
W24-A
W24-B
W39
W40
2-12
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Chapter 2
Configuration and Installation
Your SCXI-1120 is shipped in the 4 Hz position. Verify that both stages are
set to the same bandwidth to ensure that the required bandwidth is
achieved. Notice that one jumper block is available for each filter stage.
SCXI-1120D Filter Jumpers
Two-stage filtering is also available on your SCXI-1120D module. The
first stage is located in the isolated section of the input channel, whereas the
second stage is located in the nonisolated section of your input channel.
Two-stage filtering eliminates the noise generated by the isolation
amplifier, producing a higher signal-to-noise ratio. Furthermore, two filter
bandwidths are available, 22.5 kHz and 4.5 kHz.
Table 2-7. SCXI-1120D Filter Jumper Allocation
First
Filter Jumper
Second
Filter Jumper
Input
Channel
Number
4.5 kHz
(Factory
Default)
22.5 kHz
22.5 kHz
4.5 kHz
(Factory
Default)
0
W17-A
W17-B
W25
W26
1
W18-A
W18-B
W27
W28
2
W19-A
W19-B
W29
W30
3
W20-A
W20-B
W31
W32
4
W21-A
W21-B
W33
W34
5
W22-A
W22-B
W35
W36
6
W23-A
W23-B
W37
W38
7
W24-A
W24-B
W39
W40
Your SCXI-1120D is shipped in the 4.5 kHz position. Verify that both
stages are set to the same bandwidth to ensure that the required bandwidth
is achieved. Notice that one jumper block is available for each filter stage.
© National Instruments Corporation
2-13
SCXI-1120/D User Manual
Chapter 2
Configuration and Installation
Hardware Installation
You can install the SCXI-1120/D in any available SCXI chassis. The
following are general installation instructions. Consult your SCXI chassis
manual for specific instructions and warnings.
1.
Turn off the computer that contains the DAQ device or disconnect it
from your SCXI chassis.
2.
Turn off the SCXI chassis. Do not insert the SCXI-1120/D into a
chassis that is powered on.
3.
Insert the SCXI-1120/D into the module guides. Gently guide the
module into the back of the slot until the connectors make contact.
If you have already installed a cable assembly in the rear of the chassis,
the module and cable assembly must be firmly engaged; however,
do not force the module into place.
4.
Screw the front mounting panel of the SCXI-1120/D to the top and
bottom threaded strips of your SCXI chassis.
5.
If you are connecting the module to a DAQ device, connect the
cable assembly from the rear signal connector of your module to the
I/O connector of your DAQ device by following the instructions in
your cable installation guide.
Note Cable your DAQ device to only one module in each chassis.
6.
Visually verify the installation.
7.
Turn on the SCXI chassis.
8.
Turn on the computer or reconnect it to your chassis.
The SCXI-1120/D module is installed and ready for operation.
SCXI-1120/D User Manual
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3
Signal Connections
This chapter describes the input and output signal connections to the
SCXI-1120/D module through the SCXI-1120/D front connector and rear
signal connector, and includes specifications and connection instructions
for the signals given on the SCXI-1120/D connectors.
The following cautions contain important safety information concerning
hazardous voltages.
Cautions Do not operate the device in an explosive atmosphere or where there may be
flammable gases or fumes.
Keep away from live circuits. Do not remove equipment covers or shields unless you are
trained to do so. If signal wires are connected to the device, hazardous voltages may exist
even when the equipment is turned off. To avoid a shock hazard, do not perform procedures
involving cover or shield removal unless you are qualified to do so and disconnect all field
power prior to removing covers or shields.
Equipment described in this document must be used in an Installation Category II
environment per IEC 664. This category requires local level supply mains-connected
installation.
Do not operate damaged equipment. The safety protection features built into this device
can become impaired if the device becomes damaged in any way. If the device is damaged,
turn the device off and do not use until service-trained personnel can check its safety. If
necessary, return the device to National Instruments for service and repair to ensure that its
safety is not compromised.
Do not operate this equipment in a manner that contradicts the information specified in this
document. Misuse of this equipment could result in a shock hazard.
Terminals are for use only with equipment that has no accessible live parts.
Do not substitute parts or modify equipment. Because of the danger of introducing
additional hazards, do not install unauthorized parts or modify the device. Return the
device to National Instruments for service and repair to ensure that its safety features are
not compromised.
© National Instruments Corporation
3-1
SCXI-1120/D User Manual
Chapter 3
Signal Connections
When using the device with high common-mode voltages, you MUST insulate your signal
wires for the highest input voltage. National Instruments is not liable for any damages or
injuries resulting from inadequate signal wire insulation. Use only 26 to 14 AWG wire with
a voltage rating of 300 V and 60 °C for measuring 250 to 300 V; use only 600 V and 60 °C
for measuring 480 V. Prepare your signal wire by stripping the insulation no more than
7 mm.
When connecting or disconnecting signal lines to the SCXI terminal block screw terminals,
make sure the lines are powered off. Potential differences between the lines and the SCXI
ground create a shock hazard while you connect the lines.
When using this module with a terminal block, connect the signal wires to the screw
terminals by inserting the stripped end of the wire fully into the terminals. Tighten the
terminals to a torque of 5 to 7 in.-lb.
Connections, including power signals to ground and vice versa, that exceed any of the
maximum signal ratings on the SCXI device, can create a shock or fire hazard or can
damage any or all of the devices connected to the SCXI chassis, the host computer, and the
SCXI device. National Instruments is not liable for any damages or injuries resulting from
incorrect signal connections.
If high voltages (≥30 Vrms and 42.4 Vpeak or 60 VDC) are present, you must connect a
safety earth ground wire to the terminal block safety ground solder lug. This complies with
safety agency requirements and protects against electric shock when the terminal block is
not connected to the chassis. To connect the safety earth ground to the safety ground solder
lug, run an earth ground wire in the cable from the signal source to the terminal block.
National Instruments IS NOT liable for any damages or injuries resulting from inadequate
safety earth ground connections.
Do not loosen or re-orient the safety ground solder lug hardware on the terminal block
when connecting the safety ground wire. To do so reduces the safety isolation between the
high voltage and safety ground.
Clean devices and terminal blocks by brushing off light dust with a soft, nonmetallic brush.
Remove other contaminants with deionized water and a stiff nonmetallic brush. The unit
must be completely dry and free from contaminants before returning to service.
Use only National Instruments high voltage TBX Series cable assemblies with
high-voltage TBX Series terminal blocks.
To comply with the UL North America or CE, use this module with a UL or CE
marked SCXI chassis.
Caution
SCXI-1120/D User Manual
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Chapter 3
Signal Connections
SCXI-1120/D Front Connector
Figure 3-1 shows the pin assignments for the SCXI-1120/D front
connector.
A
B
C
CH0+
32
CH0-
32
CH1+
30
CH1-
30
NC
28
NC
28
CH2+
26
CH2-
26
CH3+
24
CH3-
24
NC
22
NC
22
CH4+
20
CH4-
20
CH5+
18
CH5-
18
NC
16
NC
16
CH6+
14
CH6-
14
CH7+
12
CH7-
12
NC
10
NC
10
NC
8
RSVD
8
RSVD
6
RSVD
6
+5 V
4
MTEMP
4
CHSGND
2
DTEMP
2
- This symbol represents no physical pin
Figure 3-1. SCXI-1120/D Front Connector Pin Assignments
© National Instruments Corporation
3-3
SCXI-1120/D User Manual
Chapter 3
Signal Connections
Front Connector Signal Descriptions
SCXI-1120/D front connector signal descriptions are listed in Table 3-1.
Table 3-1. SCXI-1120/D Front Connector Signal Descriptions
Pin
Signal Name
Description
A2
CHSGND
Chassis Ground—Tied to the SCXI chassis.
C2
DTEMP
Direct Temperature Sensor—Connects the
temperature sensor to pin 18 of the rear signal
connector MCH7- when the terminal block is
configured for direct temperature connection
and jumper W41 is in position 3.
A4
+5 V
+5 VDC Source—Powers temperature sensor
on the terminal block. 0.2 mA of source not
protected.
C4
MTEMP
Multiplexed Temperature Sensor—Connects
temperature sensor to output multiplexer.
A6, C6, C8
RSVD
Reserved—Reserved for future use. Do not
connect any signals to these pins. TTL/CMOS
output. They are not protected.
A8, A10, C10, A16,
C16, A22, C22, A28,
C28
Not Connected
Do not connect any signals to these pins.
A12, A14, A18, A20,
A24, A26, A30, A32
CH7+ through CH0+
Positive Input Channels—Positive inputs to
channels 7 through 0, respectively.
C12, C14, C18, C20,
C24, C26, C30, C32
CH7– through CH0–
Negative Input Channels—Negative inputs to
channels 7 through 0, respectively.
The signals on the front connector are all analog with the exceptions of pins
A6, C6, and C8. The analog signals can be divided into two groups—the
analog input channels and the temperature sensor.
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Chapter 3
Signal Connections
Analog Input Channels
The SCXI-1120/D positive input channels are located in Figure 3-1
column A. Their corresponding negative input channels are located in
column C. Each input corresponds to a separate amplifier and is fully
isolated from the other channels and from earth ground. The inputs are
designed in a floating single-ended configuration, thus the measured signal
can be referenced to a ground level with common-mode voltage up to
250 Vrms. For better noise immunity, connect the negative input channel
to the signal reference. If the measured signals are floating, connect
the negative input channel to chassis ground on the terminal block.
Figure 3-2 shows how to connect a ground-referenced signal on the
SCXI-1120/D. Figure 3-3 shows how to connect a floating signal on the
SCXI-1120/D. Figures 3-4 through 3-7 show how to connect AC-coupled
signals on the SCXI-1120/D.
+
+
+
Vs
Vout
-
-
+
Vcm
High
- CMV
I
Module
Figure 3-2. Ground-Referenced Signal Connection for the SCXI-1120/D
with High Common-Mode Voltage
+
+
+
Vs
Vout
-
-
I
Module
Figure 3-3. Floating Signal Connection for the SCXI-1120/D Referenced to
Chassis Ground for Better Signal-to-Noise Ratio
© National Instruments Corporation
3-5
SCXI-1120/D User Manual
Chapter 3
Signal Connections
+
+
+
Vs
-
-
Vout
I
Module
Figure 3-4. Floating AC-Coupled Signal Connection for the SCXI-1120
+
+
Vs
Vout
-
-
+
Vcm
+
R bias
High
- CMV
I
Module
Figure 3-5. AC-Coupled Signal Connection for the SCXI-1120 with
High Common-Mode Voltage
♦
SCXI-1120
When you connect AC-coupled signals to the SCXI-1120, connect an
external resistor from the positive input channel to the signal reference to
provide the DC path for the positive input bias current. Typical resistor
values range from 100 kΩ to 1 MΩ. This solution, although necessary in
this case, lowers the input impedance of the input channel amplifier and
introduces an additional offset voltage proportional to the input bias current
and to the resistor value used. The typical input bias current of the amplifier
consists of ±80 pA and a negligible offset drift current. When a 100 kΩ
resistor is used, this will result into ±8 µV of offset, which is insignificant
in most applications. However, if larger valued bias resistors are used,
significant input offset may result. To determine the maximum offset
introduced by the biasing resistor, use the following equation:
V ofsbias = I bias × R bias
SCXI-1120/D User Manual
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Chapter 3
Signal Connections
The input signal range of an SCXI-1120 input channel is ±5 V/ Gtotal
referenced to its negative input, where Gtotal is equal to the product of the
first-stage and second-stage gains. In addition, the input channels are
overvoltage protected to 250 Vrms with power on or off at a maximum of
4.5 mArms sink or source.
♦
SCXI-1120D
When connecting AC-coupled signals to the SCXI-1120D, you do not need
to add the external resistor, as the SCXI-1120D provides a DC path
internally. Refer to Figures 3-6 and 3-7 for further details.
511 kΩ
+
+
+
Vs
-
I
+
Vcm
Vout
511 kΩ
-
High
- CMV
Module
Figure 3-6. AC-Coupled Signal Connection for the SCXI-1120D with
High Common Mode Voltage
511 kΩ
+
+
Vs
511 kΩ
-
+
Vout
-
I
Figure 3-7. Floating AC-Coupled Signal Connection for the SCXI-1120D
Temperature Sensor Connection
Pins C2 and C4 are dedicated for connecting to a terminal block
temperature sensor. The temperature sensor is not isolated and is
referenced to the chassis ground. The connection is overvoltage protected
to ±25 VDC with power on and ±15 VDC with power off.
© National Instruments Corporation
3-7
SCXI-1120/D User Manual
Chapter 3
Signal Connections
SCXI-1120/D Rear Connector
Note If you will be using the SCXI-1120/D with a National Instruments DAQ device and
cable assembly, you do not need to read the remainder of this chapter. If you will also be
using the SCXI-1180 feedthrough panel, the SCXI-1343 rear screw terminal adapter, or the
SCXI-1351 one-slot cable extender with the SCXI-1120/D, you should read this section.
Figure 3-8 shows the pin assignments for the SCXI-1120/D rear signal
connector.
AOGND
MCH0+
MCH1+
MCH2+
MCH3+
MCH4+
MCH5+
MCH6+
MCH7+
OUTREF
NC
NC
SERDATIN
DAQD*/A
SLOT0SEL*
NC
DIG GND
NC
SERCLK
NC
NC
RSVD
NC
NC
NC
1
3
5
7
9
11
13
15
17
19
21
23
25
27
29
31
33
35
37
39
41
43
45
47
49
2
4
6
8
10
12
14
16
18
20
22
24
26
28
30
32
34
36
38
40
42
44
46
48
50
AOGND
MCH0MCH1MCH2MCH3MCH4MCH5MCH6MCH7NC
NC
DIG GND
SERDATOUT
NC
NC
NC
NC
SCANCLK
NC
NC
NC
NC
NC
NC
NC
Figure 3-8. SCXI-1120/D Rear Signal Connector Pin Assignments
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Chapter 3
Signal Connections
Rear Connector Signal Descriptions
SCXI-1120/D rear connector signal descriptions are listed in Table 3-2.
Table 3-2. Rear Connector Signal Descriptions
Pin
Signal Name
Description
1–2
AOGND
Analog Output Ground—Connected to the analog reference when
jumper W46 is in position AB-R0.
3–18
MCH0±
through
MCH7±
Analog Output Channels 0 through 7—Connects to the DAQ device
differential analog input channels.
19
OUTREF
Output Reference—Serves as the reference node for the analog
output channels and the temperature sensor—in the DTS mode—in
the NRSE mode. It should be connected to the analog input sense of
the NRSE DAQ device.
24, 33
DIG GND
Digital Ground—Supply the reference for DAQ device digital
signals and are tied to the module digital ground.
25
SERDATIN
Serial Data In—Taps into the SCXIbus MOSI line to provide serial
input data to a module or slot 0.
26
SERDATOUT
Serial Data Out—Taps into the SCXIbus MISO line to accept serial
output data from a module.
27
DAQD*/A
DAQ Device Data/Address Line—Taps into the SCXIbus D*/A line
to indicate to the module whether the incoming serial stream is data
or address information.
29
SLOT0SEL*
Slot 0 Select—Taps into the SCXIbus INTR* line to indicate
whether the information on MOSI is being sent to a module or
slot 0.
36
SCANCLK
Scan Clock—Indicates to the SCXI-1120/D that a sample has been
taken by the DAQ device and causes the SCXI-1120/D to change
channels.
37
SERCLK
Serial Clock—This signal taps into the SCXIbus SPICLK line to
clock the data on the MOSI and MISO lines.
43
RSVD
Reserved.
© National Instruments Corporation
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SCXI-1120/D User Manual
Chapter 3
Signal Connections
All other pins are not connected.
The signals on the rear connector can be classified as analog output signals,
digital I/O signals, or timing I/O signals. Signal connection guidelines for
each of these groups are given in the following section.
Analog Output Signal Connections
Pins 1 through 19 of the rear connector are analog output signal pins. Pins 1
and 2 are AOGND signal pins. AOGND is an analog output common signal
that is routed through jumper W46 to the analog reference on the
SCXI-1120/D. You can use these pins for a general analog power ground
tie point to the SCXI-1120/D if necessary. In particular, when using
differential input DAQ devices, such as the MIO-16 device, it is preferable
to leave jumper W46 in its factory-default setting or in position AB-R1 to
avoid ground loops. With DAQ devices that are configured for RSE
measurements, jumper W46 should be in position AB-R0 to connect the
SCXI-1120/D analog ground reference to the DAQ analog ground. Pin 19
is the OUTREF pin, and is connected internally to the analog reference
when jumper W46 is in position AB-R2. Pins 3 through 18 are the analog
output channels of the SCXI-1120/D. Pins 3 and 4, or MCH0±, are a
multiplexed output of all eight channels and the temperature sensor output.
Pins 5 through 18, or MCH1± through MCH7±, are a parallel connection
of channels 1 through 7 to the rear connector. Pin 18 is a direct connection
to the temperature sensor when jumper W41 is in position 3. Notice that the
temperature sensor is located on the terminal block. For further details on
configuring the temperature sensor output, refer to the SCXI-1320 and
SCXI-1328 terminal block installation guides.
Note The SCXI-1120/D analog outputs are short-circuit protected.
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Chapter 3
Signal Connections
The digital I/O signals of the SCXI-1120/D match the digital I/O lines of
the MIO-16 device. When used with an SCXI-1341, SCXI-1342, or
SCXI-1344 cable assembly, the SCXI-1120/D signals match the digital
lines of the Lab-NB/Lab-PC+/Lab-LC devices and the PC-LPM-16/PnP
device, respectively. Table 3-3 lists the equivalencies. For more
information, consult your cable assembly installation guide.
Table 3-3. SCXIbus to SCXI-1120/D Rear Connector to DAQ Device Pin Equivalencies
SCXIbus Line
SCXI-1120/D
Rear Signal
Connector
MIO E Series
Device
Lab and 1200
Series Device
PC-LPM-16/PnP
MOSI
SERDATIN
DIO0
PB4
DOUT4
D*/A
DAQD*/A
DIO1
PB5
DOUT5
INTR*
SLOT0SEL*
DIO2
PB6
DOUT6
SPICLK
SERCLK
EXTSTROBE*
PB7
DOUT7
MISO
SERDATOUT
DIO4
PC1
DIN6
Specifications and ratings for the digital I/O lines are given in Appendix A,
Specifications.
© National Instruments Corporation
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SCXI-1120/D User Manual
4
Theory of Operation
This chapter contains a functional overview of the SCXI-1120/D module
and explains the operation of each functional unit making up the
SCXI-1120/D.
Functional Overview
The block diagram in Figure 4-1 illustrates the key functional components
of the SCXI-1120/D.
Isolated Section
Nonisolated
Section
Input Channel 0
+
-
Front Connector
+
Digital
Interface
and
Control
Input Channel 1
+
Rear Connector
+
SCXIbus
-
+
Timing
and
Analog
Output
Stage
Input Channel 6
+
-
+
Input Channel 7
+
-
Temparature Sensor
Figure 4-1. SCXI-1120/D Block Diagram
© National Instruments Corporation
4-1
SCXI-1120/D User Manual
Chapter 4
Theory of Operation
The major components of the SCXI-1120/D are as follows:
•
SCXIbus connector
•
Digital interface
•
Digital control circuitry
•
Timing and analog circuitry
The SCXI-1120 consists of eight isolated amplifier channels with gains of
1, 2, 5, 10, 20, 50, 100, 200, 250, 500, 1,000, and 2,000. The SCXI-1120D
consists of eight isolated amplifier channels with gains of 0.5, 1, 2.5, 5 10,
25, 50, 100, 125, 250, 500, and 1,000. The SCXI-1120/D also has a digital
section for automatic control of channel scanning and temperature
selection.
The theory of operation of each of these components is explained in the rest
of this chapter.
Power-Up State
The SCXI-1120/D powers up, or resets, in parallel mode.
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Chapter 4
Theory of Operation
SCXIbus Connector and Digital Interface
Figure 4-2 shows a diagram of the SCXI-1120/D and SCXIbus digital
interface circuitry.
SS*
MOSI
D*/A
INTR*
SPICLK
MISO
SCXIbus
DAQD*/A
Digital Interface
SLOT0SEL*
SERCLK
Buffered Digital
Signal Controls
Rear Connector
SERDATIN
Buffered Serial
Data
SERDATOUT
Figure 4-2. Digital Interface Circuitry Block Diagram
The digital interface circuitry is divided into a data acquisition section
and an SCXIbus section. The SCXI-1120/D connects to the SCXIbus
through a 4 × 24 metral receptacle and to the DAQ device through a 50-pin
ribbon-cable header. The digital interface circuitry buffers the digital
signals from the DAQ device and the SCXIbus and sends signals back and
forth between the DAQ device and the SCXIbus.
© National Instruments Corporation
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SCXI-1120/D User Manual
Chapter 4
Theory of Operation
Digital Control Circuitry
Figure 4-3 diagrams the SCXI-1120/D digital control.
Serial Data Out
Module ID Register
Input Channel
Select
Configuration
Register
Output
Stage
Control
Buffered
Serial Data In
Buffered Digital
Control Signals
SCANCLK
Path
Control
Hardware
Scan
Control
Figure 4-3. SCXI-1120/D Digital Control
The digital control section consists of the Configuration Register and the
Module ID Register.
The Configuration Register provides channel selection and configures the
SCXI-1120/D for scanning options. All the control bits are fed into a latch
before being routed to the rest of the module. The channel-select bits are
taken directly from the shift register.
The Module ID Register contains the module ID 4 hex, a code unique to the
SCXI-1120, or 44 hex, a code unique to the SCXI-1120D. You can read this
module ID over the SCXIbus to determine the type of module in a
particular slot.
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Chapter 4
Theory of Operation
Analog and Timing Circuitry
The SCXIbus provides analog power (±18.5 VDC) that is regulated on the
SCXI-1120/D to ±15 VDC, a guard, an analog bus (AB0±), and a chassis
ground (CHSGND). AB0± buses the SCXI-1120/D output to other
modules or receives outputs from other modules through the SCXIbus. The
guard guards the analog bus and can be connected through jumper W46 to
the analog ground reference or can be left floating (a connection can be
made by another device).
The DAQ device analog input and timing is the interface between the
SCXI-1120/D output and the DAQ device.
© National Instruments Corporation
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SCXI-1120/D User Manual
Chapter 4
Theory of Operation
Analog Input Channels
Figure 4-4 shows the analog input block diagram.
SCXI-1120D Only
Input Channel 0
+
511 kΩ
+
511 kΩ
LPF
-
LPF
+ To Output
- Stage
LPF
+ To Output
- Stage
LPF
+ To Output
- Stage
LPF
+ To Output
- Stage
LPF
+ To Output
- Stage
LPF
+ To Output
- Stage
LPF
+ To Output
- Stage
LPF
+ To Output
- Stage
I
SCXI-1120D Only
511 kΩ
Input Channel 1
+
511 kΩ
LPF
I
SCXI-1120D Only
511 kΩ
Input Channel 2
+
511 kΩ
LPF
I
Front Connector
SCXI-1120D Only
511 kΩ
Input Channel 3
+
511 kΩ
LPF
I
SCXI-1120D Only
511 kΩ
Input Channel 4
+
511 kΩ
LPF
I
SCXI-1120D Only
Input Channel 5
+
511 kΩ
511 kΩ
LPF
I
SCXI-1120D Only
511 kΩ
Input Channel 6
+
511 kΩ
LPF
I
SCXI-1120D Only
511 kΩ
Input Channel 7
+
511 kΩ
LPF
I
MTEMP
DTEMP
Figure 4-4. Analog Input Block Diagram
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Chapter 4
Theory of Operation
The analog input consists of eight isolated single-ended noninverting
amplifiers. In addition, lowpass filtering is available at the inputs. You can
jumper select one of two bandwidths; 10 kHz or 4 Hz for the SCXI-1120,
and 22.5 kHz or 4.5 kHz for the SCXI-1120D. The amplifier gain is divided
into two stages; a first stage providing gains of 1, 10, 50, and 100, and a
second stage providing gains of 1, 2, 5, 10, and 20. Each channel is
configurable to a different bandwidth and gain. In addition to these two
stages, the SCXI-1120D has a fixed input gain stage of 0.5.
Use the following formula to determine the overall gain of a given amplifier
input channel:
G Total = G 1ST × G 2ND for the SCXI-1120
G 1ST
G TOTAL = ----------- × G 2ND for the SCXI-1120D
2
where Gtotal is the overall gain and G1st and G2nd are the first- and
second-stage gains. Here it is important to note that the choice of gain in
each stage will affect the amplifier bandwidth. To determine the bandwidth
of a given gain stage use the following formula:
GPWP
BW = ---------------G
where BW is a given amplifier stage bandwidth, GBWP is the gain
bandwidth product (typically 800 kHz for the SCXI-1120 and 8 MHz for
the SCXI-1120D), and G is the gain at this stage. This BW might be of
concern at high first-stage gains such as 50 and 100. In this case, the
first-stage amplifier has a BW equal to 16 kHz and 8 kHz, respectively, for
the SCXI-1120, and 60 kHz and 80 kHz for the SCXI-1120D. Due to this
decrease in the amplifier bandwidth, you will notice a decrease in the
channel overall bandwidth, but a better noise immunity. If this bandwidth
limitation is unacceptable, you should spread the gains over both stages,
thus increasing the BW of each amplifier stage. This will introduce, in most
cases, a negligible effect on the channel bandwidth. For example, to achieve
a gain of 100 for the SCXI-1120, use G1st = 10 and G2nd = 10; for a gain of
1,000, use G1st = 50 and G2nd = 20. However, for the SCXI-1120D, minimal
effects are introduced at G ≤ 100. Refer to Appendix A, Specifications, for
Gain versus BW for the SCXI-1120D.
All the amplifier input channels are overvoltage protected to 250 Vrms with
power on or off.
© National Instruments Corporation
4-7
SCXI-1120/D User Manual
Chapter 4
Theory of Operation
The isolated amplifiers fulfill two purposes on the SCXI-1120/D module.
They convert a small signal riding on a high common-mode voltage into a
single-ended signal with respect to the SCXI-1120/D chassis ground. With
this conversion, the input analog signal can be extracted from a high
common-mode voltage or noise before being sampled and converted by the
DAQ device. The isolated amplifier also amplifies and conditions an input
signal, which results in an increase in measurement resolution and
accuracy.
After isolation, further filtering is available to increase the noise immunity
of the amplifier channel. It is important to note that the overall amplifier
bandwidth is determined by both filtering stages, so to achieve the required
bandwidth, both filtering sections should be set the same, as indicated in
Chapter 2, Configuration and Installation.
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Chapter 4
Theory of Operation
Analog Output Circuitry
Figure 4-5 shows the SCXI-1120/D analog output circuitry.
SCXIbus
Output
Stage
Control
ABO
Switch
Channel 0
Buffer
Output
Mux
MCH0+
Channel 7
MCH0-
Output Stage and
Hardware Scan
Control
From
Channel 1
MCH1+
From
Channel 6
MCH6+
MCH1-
Rear Connector
MTEMP
MCH6-
Analog
Reference
From
Channel 7
MCH7+
W41
DTEMP
MCH7-
Figure 4-5. Analog Output Circuitry
The SCXI-1120/D output circuitry consists of a buffered-output
multiplexer and channel-select hardware. The channel-select hardware
consists of a counter. This counter is needed when the module is operating
in the multiplexed-output mode.
© National Instruments Corporation
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SCXI-1120/D User Manual
Chapter 4
Theory of Operation
In the parallel-output mode, the counter is disabled and amplifier channel 0
is selected at the output multiplexer and is connected to MCH0. The seven
other channels are hardwired to MCH1 through MCH7 on the rear
connector.
The output multiplexer multiplexes all eight amplifier outputs and the
temperature-sensor reading provided on the MTEMP line. This
measurement is only software controlled. For hardware control of the
temperature sensor reading, connect the temperature sensor to pin 18 on the
rear connector as described in Chapter 2, Configuration and Installation.
The multiplexer output connects to the MCH0± and is connected to the
DAQ device analog channel input. In the case of the MIO DAQ devices,
MCH0± on the rear connector corresponds to ACH0 and ACH8.
Notice that when the multiplexed-output mode is selected, pins 5
through 18 on the rear connector are still driven by the SCXI-1120/D. The
SCXI-1120/D outputs on the rear connector are short-circuit protected.
Parallel Mode
When the MCH0 signal is configured to be the output of channel 0, the rear
connector simultaneously carries each of the outputs of the SCXI-1120/D
on different pins, and the module is in parallel mode. In this mode you can
use an SCXI-1180 feedthrough panel to make each of the outputs available
at the front of the chassis. A DAQ device cabled to an SCXI-1120/D in
parallel mode reads a separate output signal from the module on each of its
analog inputs. You cannot multiplex the parallel outputs of a module onto
the SCXIbus; only a DAQ device directly cabled to the module has access
to the outputs.
Multiplexed Mode (Recommended)
In multiplexed mode, the output signals for channels 1 through 7 are sent
to the rear connector but are usually ignored. All reads from the module are
from the MCH0 signal of the rear connector, which can be configured as
the output of any channel of the SCXI-1120/D or as the output of any other
module in multiplexed mode that is sending its output onto the SCXIbus.
You can also configure the SCXI-1120/D to send any one of its outputs to
the SCXIbus. Thus, in multiplexed mode only, one module in a chassis
needs to be connected to a DAQ device; you can pass signals from the other
modules to the DAQ device through the SCXIbus.
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Chapter 4
Theory of Operation
Multiplexed mode is also useful for performing scanning operations with
the SCXI-1120/D. The MIO devices, Lab-PC+, and the 1200 Series DAQ
devices all support scanning. The SCXI chassis is programmed with a
module scan list that dynamically controls which module sends its output
to the SCXIbus during a scan. You can specify this list to scan the modules
in any order, with an arbitrary number of channels for each module entry in
the list. However, the channels on the SCXI-1120/D must be scanned in a
consecutive, ascending order (after channel 7 is scanned the module wraps
back to channel 0 and continues). You can program the SCXI-1120/D to
start scans with any channel.
Note The SCXI-1120/D parallel outputs continuously drive the RSC pins even when the
module is configured in multiplexed mode.
© National Instruments Corporation
4-11
SCXI-1120/D User Manual
5
Calibration
This chapter discusses the SCXI-1120/D calibration procedures.
Calibration Equipment Requirements
For best measurement results, calibrate the SCXI-1120/D so that its offset
is adjusted to 0 ± 3 mV RTO and 0 ± 6 µV RTI. No special equipment is
needed other than a regular voltmeter with the following specifications:
•
Range: 30 mV to 300 mV
•
Resolution: 3.5 digits or greater
A multiranging 3.5-digit digital multimeter can provide you with the
necessary function as described previously. We will refer to the measuring
instrument as a digital multimeter (DMM).
Each channel on the SCXI-1120/D has two potentiometers dedicated for
calibration. One potentiometer is used to null the output offset; the other is
used to null the input offset.
Re-calibrate your SCXI-1120/D once a year.
Offset Null Adjust
To avoid erroneous results when nulling the amplifier, follow these steps in
the order indicated. To null the offset of the amplifier channels, complete
the following steps:
1.
Set the DMM range to the smallest range that can measure ±3 mV.
2.
Short the inputs of the DMM together and then to chassis ground.
3.
Record the measurement indicated by the DMM display. This is the
DMM inherent offset and it should be subtracted from subsequent
measurements.
4.
Short the desired channel inputs together and then to chassis ground.
5.
Set the amplifier gain to 1.
© National Instruments Corporation
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SCXI-1120/D User Manual
Chapter 5
Calibration
6.
Connect the amplifier output to the DMM. Make sure that the DMM
can achieve the accuracy and resolution you need.
7.
Adjust the output potentiometer of the desired channel until the output
is 0 ± 3 mV.
8.
Set the DMM range to the smallest range that can measure ±6 mV.
9.
Set the amplifier gain to 1,000.
10. Adjust the input potentiometer of the desired channel until the output
is 0 ± 6 mV.
11. Go to the next channel.
You may seal the potentiometers after calibration with antisabotage lacquer
to avoid tampering with the calibration.
Table 5-1 lists the potentiometer reference designators that correspond to
each channel.
Table 5-1. Calibration Potentiometers Reference Designators
SCXI-1120/D User Manual
Input
Channel
Number
Amplifier Channel
Input Null
Output Null
0
R08
R24
1
R10
R25
2
R12
R26
3
R14
R27
4
R16
R28
5
R18
R29
6
R20
R30
7
R21
R31
5-2
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A
Specifications
This appendix lists the specifications for the SCXI-1120 and SCX-1120D.
These are typical at 25 °C unless otherwise stated. The operating
temperature range is 0 to 50 °C.
SCXI-1120
Analog Input
Gain (jumper-selectable)........................ 1, 2, 5, 10, 20, 50, 100, 200,
250, 500, 1,000, 2,000
Output range........................................... ±5 V
Number of channels ............................... 8
Gain accuracy......................................... 0.2% of reading typ
0.6% of reading max
Nonlinearity ........................................... 0.04% of fullscale range
3 mV
Offset voltage ......................................... ±  6 µV ± -------------

Gain
Stability versus ambient temperature
200 µV/°C
Offset drift RTI ............................... ±  0.2 µV/°C ± ---------------------------

Gain 
Gain drift......................................... 20 ppm/°C
Input bias current .................................. ±80 pA
Input resistance
Normal ............................................ 1 GΩ
Power off......................................... 50 kΩ
Overload.......................................... 50 kΩ
© National Instruments Corporation
A-1
SCXI-1120/D User Manual
Appendix A
Specifications for SCXI-1120
Output resistance
Multiplexed-output mode ................100 Ω
Parallel-output mode .......................330 Ω
Filtering (jumper selectable)...................4 Hz (–10 dB) or 10 kHz
(–3 dB), 3-pole RC
Output selection time
(with 5 V step, all gains)
0.012% accuracy1 ............................5.2 µs typ
7 µs max
0.012% accuracy2 ............................3 µs
0.006% accuracy3 ............................10 µs
0.0015% accuracy3 ..........................20 µs
Rise time
4 Hz .................................................0.12 s
10 kHz .............................................70 µs
Slew rate .................................................0.15 V/µs
1
Noise (400 kHz bandwidth)
Input (gain = 1,000)
4 Hz filter .................................100 nVrms
10 kHz filter .............................4 µVrms
Output (gain = 1)
4 Hz ..........................................150 µVrms
10 kHz ......................................1 mVrms
Operating common-mode voltage ..........50 or 60 Hz
Channel to channel or
channel to earth................................250 Vrms
Common-mode rejection ratio, 50 or 60 Hz
1 kΩ in input leads ..........................160 dB min at 4 Hz bandwidth
NMR (50 or 60 Hz) .........................60 dB at 4 Hz bandwidth
1
2
3
Includes the combined effects of the SCXI-1120 and the AT-MIO-16F-5
Includes the combined effects of the SCXI-1120 and the AT-MIO-16E-2 with 1 m or 2 m cable
Includes the combined effects of the SCXI-1120 and the AT-MIO-16X with 1m or 2 m cable
SCXI-1120/D User Manual
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Appendix A
Specifications for SCXI-1120
Input protection (continuous)................. 250 Vrms max1
Output protection ................................... Continuous short-to-ground
Power consumption................................ 170 mA at ±18.5 V
50 mA at ±5 V
Digital I/O
Absolute maximum voltage
input rating ............................................. 5.5 V with respect to DIG GND
Digital input specifications (referenced to DIG GND):
V input logic high voltage............ 2 V min
IH
V input logic low voltage ............. 0.8 V max
IL
I input current leakage ................... ±1 µA max
I
Digital output specifications (referenced to DIG GND):
V
V
OH
OL
output logic high voltage ........ 3.7 V min at 4 mA max
output logic low voltage.......... 0.4 V max at 4 mA max
Physical
Dimensions............................................. 3.1 by 17.3 by 20.3 cm.
(1.2 by 6.8 by 8.0 in.)
Connectors ............................................. 50-pin male ribbon-cable rear
connector, 32-pin DIN C male
front connector(18-screw
terminal adapter available)
Environment
Operating temperature ........................... 0 to 50 °C
Storage temperature .............................. –20 to 70 °C
Relative humidity ................................... 5% to 90% noncondensing
1
Module designed to meet IEC-1010 standard for double or reinforced insulation for category II pollution degree 2
© National Instruments Corporation
A-3
SCXI-1120/D User Manual
Appendix A
Specifications for SCXI-1120
Safety
Designed in accordance with IEC 61010-1, UL3111-1, and
CAN/CSA C22.2 No. 1010.1 for electrical measuring and test equipment.
Approved at altitudes up to 2000 m
Installation Category II
Pollution Degree 2
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Appendix A
Specifications for SCXI-1120D
SCXI-1120D
Analog Input
Input Characteristics
Number of channels ............................... 8 differential
Table A-1. Input Signal Range
Channel Bandwidth
Gain
Range
Filter at 22.5 K
Filter at 4.5 K
0.5
±10 V
22.5 K
4.5 K
1
±5 V
22.5 K
4.5 K
2.5
±2 V
22.5 K
4.5 K
5
±1 V
22.5 K
4.5 K
10
±0.5 V
22 K
4.5 K
25
±0.2 V
22 K
4.5 K
50
±0.1 V
22 K
4.5 K
100
±50 mV
20 K
4.5 K
250
±20 mV
20 K
4K
500
±10 mV
17 K
4K
1000
±5 mV
14 K
3.5 K
Input coupling ........................................ DC or AC with TBX-1329 or
SCXI-1305
Maximum working voltage
(Signal + CMV) ..................................... 250 Vrms
Overvoltage protection........................... 250 Vrms on or off
© National Instruments Corporation
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SCXI-1120/D User Manual
Appendix A
Specifications for SCXI-1120D
Transfer Characteristics
Nonlinearity ............................................0.04% FSR
Offset error RTI ......................................±(6 µV ±3 mV/gain)
Gain error................................................0.4% of reading typ
0.6% max
Amplifier Characteristics
Input impedance
Power on..........................................1 MΩ
Power off and overvoltaged.............500 kΩ
Input bias current ....................................15 pA
CMRR at DC1 .........................................≥ 110 dB
CMRR at 50 or 60 Hz1 ...........................≥ 98 dB
Output range ...........................................± 5 V
Output impedance...................................100 Ω in multiplexed mode 330 Ω
in parallel mode
Dynamic Characteristics
Bandwidth (–3 dB) .................................4.5 kHz or 22.5 kHz jumper
selectable
Slew Rate ................................................2 V/µs
Table A-2. System Noise RTI (0.1 Hz to 50 kHz)
1
Gain
Noise
0.5
10 µVrms/√Hz
1,000
0.1 µVrms/√Hz
0 Ω in low lead
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Appendix A
Specifications for SCXI-1120D
Table A-3. Switching Supply Noise (approximately at 100 kHz)†
Gain
Noise
0.5
174 µVrms
1,000
4 µVrms
† Earth ground referenced input signal
Phase shift using TBX-1329 AC coupled
Input to output................................. < 0.5 ° between 5 Hz and 280 Hz
Channel to channel.......................... < 0.5 ° up to 5 kHz
THD ................................................ < 0.1% at 7Vrms f = 1 kHz,
G = 0.5
< 1.5% at 3 mVrms f = 1 kHz,
G = 1,000
Crosstalk (50 Ω load and source)........... 80 dB at 1 kHz
Output selection time (with V step, all gains)
to ± 0.012% accuracy............................. 3 µs
Filter
Type ....................................................... Second order low-pass RC filter
Cutoff frequency (–3 dB) ....................... 4.5 kHz, 22.5 kHz
Stability
Recommended warm-up ........................ 30 min.
Offset drift RTI ...................................... ± (20 ± 220/gain) µV/°C
Gain drift ................................................ ± 50 ppm/°C
© National Instruments Corporation
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SCXI-1120/D User Manual
Appendix A
Specifications for SCXI-1120D
Digital I/O
Absolute maximum voltage
input rating............................................. 5.5 V with respect to DIG GND
Digital input specifications (referenced to DIG GND):
V input logic high voltage ............ 2 V min
IH
V input logic low voltage.............. 0.8 V max
IL
I input current leakage .................... ±1 µA max
I
Digital output specifications (referenced to DIG GND):
V
V
OH
OL
output logic high voltage ......... 3.7 V min at 4 mA max
output logic low voltage .......... 0.4 V max at 4 mA max
Physical
Dimensions .............................................3.1 by 17.3 by 20.3 cm.
(1.2 by 6.8 by 8.0 in.)
Connectors ..............................................50-pin male ribbon-cable rear
connector, 32-pin DIN C male
front connector(18-screw
terminal adapter available)
Environment
Operating temperature ............................0 to 50 °C
Storage temperature ................................–20 to 70 °C
Relative humidity ...................................5% to 90% noncondensing
Safety
Designed in accordance with IEC 61010-1, UL3111-1, and
CAN/CSA C22.2 No. 1010.1 for electrical measuring and test equipment.
Approved at altitudes up to 2000 m
Installation Category II
Pollution Degree 2
SCXI-1120/D User Manual
A-8
www.natinst.com
Technical Support Resources
B
This appendix describes the comprehensive resources available to you in
the Technical Support section of the National Instruments Web site and
provides technical support telephone numbers for you to use if you have
trouble connecting to our Web site or if you do not have internet access.
NI Web Support
To provide you with immediate answers and solutions 24 hours a day,
365 days a year, National Instruments maintains extensive online technical
support resources. They are available to you at no cost, are updated daily,
and can be found in the Technical Support section of our Web site at
www.natinst.com/support.
Online Problem-Solving and Diagnostic Resources
•
KnowledgeBase—A searchable database containing thousands of
frequently asked questions (FAQs) and their corresponding answers or
solutions, including special sections devoted to our newest products.
The database is updated daily in response to new customer experiences
and feedback.
•
Troubleshooting Wizards—Step-by-step guides lead you through
common problems and answer questions about our entire product line.
Wizards include screen shots that illustrate the steps being described
and provide detailed information ranging from simple getting started
instructions to advanced topics.
•
Product Manuals—A comprehensive, searchable library of the latest
editions of National Instruments hardware and software product
manuals.
•
Hardware Reference Database—A searchable database containing
brief hardware descriptions, mechanical drawings, and helpful images
of jumper settings and connector pinouts.
•
Application Notes—A library with more than 100 short papers
addressing specific topics such as creating and calling DLLs,
developing your own instrument driver software, and porting
applications between platforms and operating systems.
© National Instruments Corporation
B-1
SCXI-1120/D User Manual
Appendix B
Technical Support Resources
Software-Related Resources
•
Instrument Driver Network—A library with hundreds of instrument
drivers for control of standalone instruments via GPIB, VXI, or serial
interfaces. You also can submit a request for a particular instrument
driver if it does not already appear in the library.
•
Example Programs Database—A database with numerous,
non-shipping example programs for National Instruments
programming environments. You can use them to complement the
example programs that are already included with National Instruments
products.
•
Software Library—A library with updates and patches to application
software, links to the latest versions of driver software for National
Instruments hardware products, and utility routines.
Worldwide Support
National Instruments has offices located around the globe. Many branch
offices maintain a Web site to provide information on local services. You
can access these Web sites from www.natinst.com/worldwide.
If you have trouble connecting to our Web site, please contact your local
National Instruments office or the source from which you purchased your
National Instruments product(s) to obtain support.
For telephone support in the United States, dial 512 795 8248. For
telephone support outside the United States, contact your local branch
office:
Australia 03 9879 5166, Austria 0662 45 79 90 0, Belgium 02 757 00 20,
Brazil 011 284 5011, Canada (Calgary) 403 274 9391,
Canada (Ontario) 905 785 0085, Canada (Québec) 514 694 8521,
China 0755 3904939, Denmark 45 76 26 00, Finland 09 725 725 11,
France 01 48 14 24 24, Germany 089 741 31 30, Greece 30 1 42 96 427
Hong Kong 2645 3186, India 91805275406, Israel 03 6120092,
Italy 02 413091, Japan 03 5472 2970, Korea 02 596 7456,
Mexico (D.F.) 5 280 7625, Mexico (Monterrey) 8 357 7695,
Netherlands 0348 433466, Norway 32 27 73 00, Singapore 2265886,
Spain (Barcelona) 93 582 0251, Spain (Madrid) 91 640 0085,
Sweden 08 587 895 00, Switzerland 056 200 51 51,
Taiwan 02 2377 1200, United Kingdom 01635 523545
SCXI-1120/D User Manual
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Glossary
Prefix
Meaning
Value
p-
pico-
10 –12
n-
nano-
10 –9
µ-
micro-
10 – 6
m-
milli-
10 –3
k-
kilo-
10 3
M-
mega-
10 6
Numbers/Symbols
°
degrees
Ω
ohms
+5 V (signal)
+5 VDC Source signal
A
A
amperes
AB0+
Positive Analog Bus 0 signal
AB0–
Negative Analog Bus 0 signal
AB0EN
Analog Bus 0 Enable bit
ACH#
data acquisition device Analog Input Channel Number
A/D
analog-to-digital
AOGND
Analog Output Ground signal
Arms
amperes, root mean square
AWG
American Wire Gauge
© National Instruments Corporation
G-1
SCXI-1120/D User Manual
Glossary
B
BW
bandwidth
C
C
Celsius
CH#+
Positive Input Channel Number signal
CH#–
Negative Input Channel Number signal
CHAN
Channel Select bit
CHS
Chassis bit
CHSGND
Chassis Ground signal
CJR
cold-junction reference
CLKEN
Clock Enable bit
CLKOUTEN
Scan Clock Output Enable bit
CLKSELECT
Scan Clock Select bit
CNT
Count bit
D
D*/A
Data/Address signal
D/A
digital-to-analog
DAQD*/A
Data Acquisition Board Data/Address Line signal
dB
decibels
DIG GND
Digital Ground signal
DIN
Deutsche Industrie Norme
DMM
digital multimeter
SCXI-1120/D User Manual
G-2
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Glossary
DTEMP
Direct Temperature Sensor signal
DTS
direct temperature sensor
F
F
Fahrenheit
FIFO
first-in-first-out
FOUTEN*
Forced Output Enable bit
FRT
Forced Retransmit bit
G
GBWP
gain bandwidth product
GUARD
Guard signal
H
hex
hexadecimal
HSCR
Hardscan Control Register
HSRS*
Hardscan Reset bit
Hz
hertz
I
II
input current leakage
in.
inches
INTR*
Interrupt signal
I/O
input/output
© National Instruments Corporation
G-3
SCXI-1120/D User Manual
Glossary
K
K
kelvin
L
LOAD*
Load bit
LSB
least significant bit
M
m
meters
M
megabytes of memory
MCH#+
Positive Analog Output Channel Number signal
MCH#–
Negative Analog Output Channel Number signal
MIO
multifunction I/O
MISO
Master-In-Slave-Out signal
MOD
Module Number bit
MOSI
Master-Out-Slave-In signal
MSB
most significant bit
MTEMP
Multiplexed Temperature Sensor signal
MTS
multiplexed tempe
N
NRSE
SCXI-1120/D User Manual
nonreferenced single-ended (input)
G-4
www.natinst.com
Glossary
O
ONCE
Once bit
OUTREF
Output Reference signal
P
ppm
parts per million
R
RAM
random-access memory
RD
Read bit
RESET*
Reset signal
rms
root mean square
RSC
rear signal connector
RSE
referenced single-ended (input)
RSVD
Reserved bit/signal
RTD
resistance temperature detector
RTEMP
Read Temperature bit
RTI
referred to input
RTO
referred to output
RTSI
Real-Time System Integration
S
SCANCLK
Scan Clock signal
SCANCLKEN
Scan Clock Enable bit
© National Instruments Corporation
G-5
SCXI-1120/D User Manual
Glossary
SCANCON
Scanning Control signal
SCANCONEN
Scan Control Enable bit
SCXI
Signal Conditioning eXtensions for Instrumentation (bus)
SDK
Software Developer's Kit
s
seconds
SERCLK
Serial Clock signal
SERDATIN
Serial Data In signal
SERDATOUT
Serial Data Out signal
SL
Slot bit
SLOT0SEL*
Slot 0 Select signal
SPI
Serial Peripheral Interface
SPICLK
Serial Peripheral Interface Clock signal
SS*
Slot Select signal
T
tempco
temperature coefficient
TRIG0
Trigger 0 signal
U
UL
Underwriters Laboratory
V
V
volts
V+
Positive Analog Supply signal
V–
Negative Analog Supply signal
SCXI-1120/D User Manual
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Glossary
VDC
volts direct current
VIH
input logic high voltage
VIL
input logic low voltage
VOH
output logic high voltage
VOL
output logic low voltage
Vrms
volts, root mean square
W
W
watts
© National Instruments Corporation
G-7
SCXI-1120/D User Manual
Index
Numbers
SCXI-1120/D
description, 3-5
floating signal connections referenced
to chassis ground (figure), 3-5
ground-referenced signal connections
(figure), 3-5
analog input specifications
SCXI-1120, A-1 to A-4
SCXI-1120/D, A-5 to A-7
amplifier characteristics, A-6
dynamic characteristics, A-6 to A-7
filter, A-7
input characteristics, A-5
stability, A-7
transfer characteristics, A-6
analog output circuitry, 4-9 to 4-11
diagram, 4-9
multiplexed mode, 4-10 to 4-11
parallel mode, 4-10
analog output signal connections, 3-10 to 3-11
AOGND signal (table), 3-9
+5V signal (table), 3-4
A
AC-coupled signal connections (figure)
SCXI-1120, 3-6
SCXI-1120D, 3-7
analog and timing circuitry, 4-5 to 4-11
analog input block diagram, 4-6
analog output circuitry, 4-9 to 4-11
formula for gain determination, 4-7
analog configuration, 2-8 to 2-13
direct temperature connection, 2-10
gain jumpers, 2-10 to 2-12
grounding, shielding, and reference-mode
selection, 2-8 to 2-9
jumper W41 (table), 2-10
jumper W46, 2-8 to 2-9
SCXI-1120 filter jumpers, 2-12 to 2-13
SCXI-1120/D filter jumpers, 2-13
analog input channels, 3-5 to 3-7
analog input block diagram, 4-6
SCXI-1120
AC-coupled signal connections
(figure), 3-6
description, 3-6 to 3-7
floating AC-coupled signal connections
(figure), 3-6
SCXI-1120D
AC-coupled signal connections
(figure), 3-7
description, 3-7
floating AC-coupled signal connections
(figure), 3-7
© National Instruments Corporation
C
calibration, 5-1 to 5-2
equipment requirements, 5-1
offset null adjust, 5-1 to 5-2
potentiometer reference designators
(table), 5-2
CH7+ through CH0+ signals (table), 3-4
CH7- through CH0- signals (table), 3-4
CHSGND signal (table), 3-4
ComponentWorks software, 1-3
I-1
SCXI-1120/D User Manual
Index
digital I/O specifications
SCXI-1120, A-3
SCXI-1120/D, A-8
digital signal connections, 2-4 to 2-8
jumper W42 and W43, 2-5 to 2-6
Revisions A and B of
SCXI-1120, 2-5
Revisions C and later of
SCXI-1120/D, 2-5 to 2-6
summary of settings (table),
2-7 to 2-8
jumper W44, 2-6
all Revisions of SCXI-1120/D, 2-6
description (table), 2-8
Revision C of SCXI-1120/D, 2-6
Revisions A and B of
SCXI-1120, 2-6
summary of settings (table), 2-8
jumper W45 (table), 2-8
direct temperature connection, 2-10
documentation
conventions used in manual, ix-x
National Instruments documentation, x
DTEMP signal (table), 3-4
configuration, 2-1 to 2-13. See also
installation.
analog configuration, 2-8 to 2-13
direct temperature connection, 2-10
gain jumpers, 2-10 to 2-12
grounding, shielding, and
reference-mode selection,
2-8 to 2-9
jumper W41 (table), 2-10
jumper W46, 2-8 to 2-9
SCXI-1120 filter jumpers,
2-12 to 2-13
SCXI-1120/D filter jumpers, 2-13
digital signal connections, 2-4 to 2-8
jumpers W42 and W43, 2-5 to 2-6
jumpers W44, 2-6
summary of jumper settings (table),
2-7 to 2-8
jumpers
fixed jumpers, 2-3
parts locator diagram, 2-2
steps for configuring, 2-4
user-configurable jumpers, 2-3
removing SCXI module cover
(figure), 2-4
revision letter location (note), 2-3
Configuration Register, 4-4
conventions used in manual, ix-x
E
environment specifications
SCXI-1120, A-3
SCXI-1120/D, A-8
equipment, optional, 1-5
D
DAQD*/A signal
description (table), 3-9
SCXIbus to SCXI-1120/D to DAQ device
pin equivalencies (table), 3-11
diagnostic resources, online, B-1
DIG GND signal (table), 3-9
digital control circuitry, 4-4
digital interface circuitry block diagram, 4-3
SCXI-1120/D User Manual
F
filter jumpers
SCXI-1120, 2-12 to 2-13
SCXI-1120/D, 2-13
fixed jumpers, 2-3
I-2
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Index
digital signal connections, 2-4 to 2-8
jumper W42 and W43, 2-5 to 2-6
jumper W44, 2-6
jumper W45 (table), 2-8
fixed jumpers, 2-3
parts locator diagram, 2-2
steps for configuring, 2-4
user-configurable jumpers, 2-3
floating AC-coupled signal connections
(figure)
SCXI-1120, 3-6
SCXI-1120D, 3-7
floating signal connections referenced to
chassis ground (figure), 3-5
front connector, 3-3 to 3-7
analog input channels, 3-5 to 3-7
pin assignments (figure), 3-3
signal descriptions (table), 3-4
temperature sensor connections, 3-7
L
LabVIEW software, 1-3
LabWindows/CVI software, 1-4
G
gain determination, calculating, 4-7
gain jumpers for SCXI-1120/D, 2-10 to 2-12
allocation (table), 2-10 to 2-11
positions (table), 2-11 to 2-12
grounding, jumper W46 settings (table),
2-8 to 2-9
ground-referenced signal connections
(figure), 3-5
M
manual. See documentation.
MCH0± through MCH7± signals (table), 3-9
module configuration. See configuration.
Module ID Register, 4-4
MTEMP signal (table), 3-4
multiplexed mode, 4-10 to 4-11
I
N
installation. See also configuration.
hardware installation, 2-14
unpacking the SCXI-1120/D, 1-3
National Instruments application software,
1-3 to 1-4
National Instruments Web support, B-1 to B-2
NI-DAQ driver software, 1-4 to 1-5
J
O
jumpers
analog configuration, 2-8 to 2-13
gain jumpers, 2-10 to 2-12
jumper W41, direct temperature
connection, 2-10
jumper W46, grounding, shielding,
and reference-mode selection,
2-8 to 2-9
SCXI-1120 filter jumpers,
2-12 to 2-13
SCXI-1120/D filter jumpers, 2-13
© National Instruments Corporation
online problem-solving and diagnostic
resources, B-1
operation of SCXI-1120/D. See theory of
operation.
OUTREF signal (table), 3-9
I-3
SCXI-1120/D User Manual
Index
P
powerup state, 4-2
requirements for getting started, 1-2
revision letter location (note), 2-3
software programming choices, 1-3 to 1-5
National Instruments application
software, 1-3 to 1-4
NI-DAQ driver software, 1-4 to 1-5
unpacking, 1-3
SCXIbus connector and digital interface, 4-3
SCXIbus to SCXI-1120/D to DAQ device pin
equivalencies (table), 3-11
SERCLK signal
description (table), 3-9
SCXIbus to SCXI-1120/D to DAQ device
pin equivalencies (table), 3-11
SERDATIN signal
description (table), 3-9
SCXIbus to SCXI-1120/D to DAQ device
pin equivalencies (table), 3-11
SERDATOUT signal
description (table), 3-9
SCXIbus to SCXI-1120/D to DAQ device
pin equivalencies (table), 3-11
shielding, jumper W46 settings (table),
2-8 to 2-9
signal connections, 3-1 to 3-11
front connector, 3-3 to 3-7
analog input channels, 3-5 to 3-7
pin assignments (figure), 3-3
signal descriptions (table), 3-4
temperature sensor connections, 3-7
rear connector, 3-8 to 3-11
analog output signal connections,
3-10 to 3-11
pin assignments (figure), 3-8
SCXIbus to SCXI-1120/D to DAQ
device pin equivalencies
(table), 3-11
signal descriptions (table), 3-9
safety precautions, 3-1 to 3-2
parallel mode, 4-10
parts locator diagram, 2-2
physical specifications
SCXI-1120, A-3
SCXI-1120/D, A-8
pin assignments
front connector (figure), 3-3
rear connector (figure), 3-8
powerup state, 4-2
problem-solving and diagnostic resources,
online, B-1
R
rear connector, 3-8 to 3-11
analog output signal connections,
3-10 to 3-11
pin assignments (figure), 3-8
SCXIbus to SCXI-1120/D to DAQ device
pin equivalencies (table), 3-11
signal descriptions (table), 3-9
reference mode selection, jumper W46
settings (table), 2-8 to 2-9
requirements for getting started, 1-2
revisions
jumper settings. See jumpers.
letter location (note), 2-3
S
safety specifications
SCXI-1120, A-4
SCXI-1120/D, A-8
SCANCLK signal (table), 3-9
SCXI-1120/D. See also theory of operation.
block diagram, 4-1
features and overview, 1-1 to 1-2
major components, 4-2
optional equipment, 1-5
parts locator diagram, 2-2
SCXI-1120/D User Manual
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Index
block diagram of SCXI-1120/D, 4-1
digital control circuitry, 4-4
functional overview, 4-1 to 4-2
SCXIbus connector and digital
interface, 4-3
SLOT0SEL* signal
description (table), 3-9
SCXIbus to SCXI-1120/D to DAQ device
pin equivalencies (table), 3-11
software programming choices, 1-3 to 1-5
National Instruments application
software, 1-3 to 1-4
NI-DAQ driver software, 1-4 to 1-5
software-related resources, B-2
specifications, A-1 to A-8
SCXI-1120, A-1 to A-4
analog input, A-1 to A-3
digital I/O, A-3
environment, A-3
physical, A-3
safety, A-4
SCXI-1120/D, A-5 to A-8
amplifier characteristics, A-6
analog input, A-5 to A-7
digital I/O, A-8
dynamic characteristics, A-6 to A-7
environment, A-8
filter, A-7
input characteristics, A-5
physical, A-8
safety, A-8
stability, A-7
transfer characteristics, A-6
system requirements, 1-2
U
user-configurable jumpers, 2-3
V
VirtualBench software, 1-4
W
W41 jumper, direct temperature
connection, 2-10
W42 and W43 jumpers, 2-5 to 2-6
all Revisions of SCXI-1120D, 2-5 to 2-6
Revisions A and B of SCXI-1120, 2-5
Revisions C and later of SCXI-1120,
2-5 to 2-6
summary of settings (table), 2-7 to 2-8
W44 jumper, digital signal connections
all Revisions of SCXI-1120/D, 2-6
description (table), 2-8
Revision C of SCXI-1120/D, 2-6
Revisions A and B of SCXI-1120, 2-6
summary of settings (table), 2-8
W45 jumper (table), 2-8
W46 jumper
grounding, shielding, and reference-mode
selection, 2-8
settings (table), 2-9
Web support from National Instruments,
B-1 to B-2
online problem-solving and diagnostic
resources, B-1
software-related resources, B-2
Worldwide technical support, B-2
T
technical support resources, B-1 to B-2
temperature connection, direct, 2-10
temperature sensor connection, 3-7
theory of operation, 4-1 to 4-11
analog and timing circuitry, 4-5 to 4-11
analog input channels (figure), 4-6
analog output circuitry, 4-9 to 4-11
formula for gain determination, 4-7
© National Instruments Corporation
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SCXI-1120/D User Manual