National Instruments SC-2040 User manual

© Copyright 1994 National Instruments Corporation.
All Rights Reserved.
SC-2040
User Manual
Eight-Channel Simultaneous Sample-and-Hold Accessory
September 1994 Edition
Part Number 371191A-01

National Instruments Corporate Headquarters
6504 Bridge Point Parkway
Austin, TX 78730-5039
[phone]
Technical support fax: [phone]
[phone]
Branch Offices:
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Germany 089/741 31 30, Italy 02/48301892, Japan [phone], Netherlands 03480-33466, Norway 32-848400,
Spain (91) 640 0085, Sweden 08-730 49 70, Switzerland 056/20 51 51, U.K. 0635 523545

Limited Warranty
The SC-2040 is warranted against defects in materials and workmanship for a period of one year from the date of
shipment, as evidenced by receipts or other documentation. National Instruments will, at its option, repair or replace
equipment that proves to be defective during the warranty period. This warranty includes parts and labor.
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 manual 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
LabVIEW®, NI-DAQ®, and RTSI®are trademarks of National Instruments Corporation.
Product names and company names listed are trademarks or trade names of their respective companies.

Warning Regarding Medical and Clinical Use
of National Instruments Products
National Instruments products are not designed with components and testing intended to ensure a level of reliability
suitable for use in treatment and diagnosis of humans. Applications of National Instruments products involving
medical or clinical treatment can create a potential for accidental injury caused by product failure, or by errors on
the part of the user or application designer. Any use or application of National Instruments products for or involving
medical or clinical treatment must be performed by properly trained and qualified medical personnel, and all
traditional medical safeguards, equipment, and procedures that are appropriate in the particular situation to prevent
serious injury or death should always continue to be used when National Instruments products are being used.
National Instruments products are NOT intended to be a substitute for any form of established process, procedure, or
equipment used to monitor or safeguard human health and safety in medical or clinical treatment.

© National Instruments Corporation v SC-2040 User Manual
Contents
About This Manual................................................................................................................ix
Organization of This Manual............................................................................................ix
Conventions Used in This Manual....................................................................................x
The National Instruments Documentation Set..................................................................x
Related Documentation ....................................................................................................xi
Customer Communication................................................................................................xi
Chapter 1
Introduction..........................................................................................................................1-1
About the SC-2040.........................................................................................................1-1
What You Need to Get Started ......................................................................................1-1
Software Programming Choices....................................................................................1-2
LabVIEW and LabWindows Application Software..........................................1-2
NI-DAQ Driver Software...................................................................................1-2
Register-Level Programming.............................................................................1-4
Optional Equipment.......................................................................................................1-4
Unpacking......................................................................................................................1-4
Chapter 2
Configuration and Installation....................................................................................... 2-1
Board Configuration ......................................................................................................2-1
Supplementary Configuration Information........................................................2-6
Power Supply Selection.........................................................................2-6
Shield Selection......................................................................................2-6
DAQ Board Ground Isolation Selection................................................2-6
Gain Selection....................................................................................................2-6
Input Mode Selection.........................................................................................2-7
Installation......................................................................................................................2-8
Power On Sequence.......................................................................................................2-8
Chapter 3
Signal Connections.............................................................................................................3-1
I/O Connector Pin Description.......................................................................................3-1
Signal Connection Description..........................................................................3-4
Analog Signal Input...........................................................................................3-7
DC-Coupled Inputs................................................................................3-7
AC-Coupled Signals ..............................................................................3-8
Analog Input Ranges..................................................................3-10
Digital Signal Input............................................................................................3-11
Monitoring Signal Outputs.................................................................................3-11
Other Connection Considerations..................................................................................3-11

Contents
SC-2040 User Manual vi © National Instruments Corporation
Chapter 4
Theory of Operation..........................................................................................................4-1
Functional Overview......................................................................................................4-1
Analog Circuitry ............................................................................................................4-3
Input Protection..................................................................................................4-3
Amplification.....................................................................................................4-3
Track-and-Hold (T/H) Circuitry........................................................................4-3
Triggering from the DAQ Board ...........................................................4-4
External Triggering................................................................................4-5
Output Connection.................................................................................4-6
Power Supply.........................................................................................4-6
Chapter 5
Calibration Procedures.....................................................................................................5-1
Software Calibration......................................................................................................5-1
Offset Adjustment..............................................................................................5-1
Gain Adjustment................................................................................................5-2
Linearity Adjustment.........................................................................................5-2
Hardware Calibration.....................................................................................................5-2
Appendix A
Specifications........................................................................................................................ A-1
Appendix B
Customer Communication...............................................................................................B-1
Glossary........................................................................................................................Glossary-1
Index..................................................................................................................................Index-1

Contents
© National Instruments Corporation vii SC-2040 User Manual
Figures
Figure 1-1. The Relationship between the Programming Environment,
NI-DAQ, and Your Hardware.............................................................................1-3
Figure 2-1. SC-2040 Parts Locator Diagram..........................................................................2-2
Figure 3-1. SC-2040 I/O Connectors J11 and J12..................................................................3-2
Figure 3-2. SC-2040 Signal Routing......................................................................................3-6
Figure 3-3. Ground-Referenced Signal Connection...............................................................3-7
Figure 3-4. Floating Signal Connection.................................................................................3-8
Figure 3-5. Ground-Referenced AC-Coupled Signal Connection .........................................3-9
Figure 3-6. Ground-Offset AC-Coupled Signal Connection..................................................3-9
Figure 3-7. Floating AC-Coupled Signal Connection............................................................3-10
Figure 4-1. SC-2040 Block Diagram......................................................................................4-2
Figure 4-2. T/H Amplifier Hold Settling Time and Track Acquisition Time........................4-4
Figure 4-3. MIO-16E Controlled Triggering..........................................................................4-5
Figure 4-4. External Triggering..............................................................................................4-6
Tables
Table 2-1. Power Supply Selection.......................................................................................2-3
Table 2-2. Shield Selection...................................................................................................2-4
Table 2-3. DAQ Board Ground Isolation Selection..............................................................2-4
Table 2-4. Channel Gain Selection.......................................................................................2-5
Table 2-5. Channel Input Mode............................................................................................2-5
Table 2-6. Gain Switches for Each Channel.........................................................................2-6
Table 2-7. Switch Settings for Gain Selection......................................................................2-7
Table 2-8. Input Mode Selection Jumpers............................................................................2-7
Table 3-1. Pin Assignments for Connectors J11 and J12......................................................3-3
Table 3-2. Input Connectors Signal Summary......................................................................3-4
Table 3-3. Output Connectors (J11 and J12) Signal Summary.............................................3-4
Table 5-1. Calibration Component Identification.................................................................5-3

© National Instruments Corporation ix SC-2040 User Manual
About This Manual
This manual describes the electrical and mechanical aspects of the SC-2040 and contains
information concerning its configuration and operation. The SC-2040 is an eight-channel
simultaneously sampling differential amplifier for the National Instruments MIO-16E Series
DAQ boards. The SC-2040 samples all eight channels at the same time, preserving interchannel
phase relationships for the MIO-16E.
Organization of This Manual
The SC-2040 User Manual is organized as follows:
• Chapter 1, Introduction, describes the SC-2040, lists what you need to get started with your
SC-2040, describes the optional software and optional equipment, and explains how to
unpack your SC-2040.
• Chapter 2, Configuration and Installation, describes the configuration and installation of
your SC-2040. The topics discussed are switch and jumper configuration, connection of the
SC-2040 to the MIO-16E, and the power-on sequence for your SC-2040 configuration.
• Chapter 3, Signal Connections, describes the signal connections to the SC-2040 board, and
cable wiring.
• Chapter 4, Theory of Operation, contains a functional overview of the SC-2040 board and
explains the operation of each functional unit making up the SC-2040.
• Chapter 5, Calibration Procedures, discusses the calibration procedures for the SC-2040
board.
• Appendix A, Specifications, lists the specifications for the SC-2040.
• Appendix B, Customer Communication, contains forms you can use to request help from
National Instruments or to comment on our products.
• The Glossary contains an alphabetical list and description of terms used in this manual,
including abbreviations, acronyms, metric prefixes, mnemonics, and symbols.
• The Index contains an alphabetical list of key terms and topics used in this manual, including
the page where you can find each one.

About This Manual
SC-2040 User Manual x © National Instruments Corporation
Conventions Used in This Manual
The following conventions are used in this manual:
bold italic Bold, italic text denotes a note, caution, or warning.
italic Italic text denotes emphasis, a cross reference, or an introduction to a key
concept.
MIO-16E MIO-16E refers to the National Instruments E-Series of MIO-16 DAQ
boards unless otherwise noted.
monospace Lowercase text in this font denotes text or characters that are to be literally
input from the keyboard, sections of code, programming examples, and
syntax examples. This font is also used for the proper names of disk
drives, paths, directories, programs, subprograms, subroutines, device
names, functions, variables, filenames, and extensions, and for statements
and comments taken from program code.
Abbreviations, acronyms, metric prefixes, mnemonics, symbols, and terms are listed in the
Glossary.
The National Instruments Documentation Set
The SC-2040 User Manual is one piece of the documentation set for your 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:
• Your DAQ hardware user manuals–These manuals have detailed information about the DAQ
hardware that plugs into or is connected to your computer. Use these manuals for hardware
installation and configuration instructions, specification information about your DAQ
hardware, and application hints.
• Software manuals–Examples of software manuals you might have are the LabVIEW and
LabWindows®manual sets and the NI-DAQ manuals. After you set up your hardware
system, use either the application software (LabVIEW or LabWindows) manuals or the
NI-DAQ manuals to help you write your application. If you have a large and complicated
system, it is worthwhile to look through the software manuals before you configure your
hardware.
• Accessory manuals–If you are using accessory products, read the terminal block and cable
assembly installation guides or accessory board user manuals. They explain how to
physically connect the relevant pieces of the system together. Consult these guides when you
are making your connections.

About This Manual
© National Instruments Corporation xi SC-2040 User Manual
Related Documentation
The following document contains information that you may find helpful as you read this manual:
• Your DAQ hardware user manual
Customer Communication
National Instruments wants to receive your comments on our products and manuals. We are
interested in the applications you develop with our products, and we want to help if you have
problems with them. To make it easy for you to contact us, this manual contains comment and
configuration forms for you to complete. These forms are in Appendix B, Customer
Communication, at the end of this manual.

© National Instruments Corporation 1-1 SC-2040 User Manual
Chapter 1
Introduction
This chapter describes the SC-2040, lists what you need to get started with your SC-2040,
describes the optional software and optional equipment, and explains how to unpack your
SC-2040.
About the SC-2040
The SC-2040 is an eight-channel simultaneously sampling differential amplifier for the National
Instruments MIO-16E Series DAQ boards. Each channel provides DIP-switch-selectable gain
followed by a track-and-hold amplifier. The track-and-hold amplifiers sample all the inputs at
the same time, which is useful for preserving interchannel phase relationships. The MIO-16E
can trigger the track-and-hold amplifiers, or you can supply an external trigger source.
Note: When a board is referred to without an AT prefix (that is, MIO-16E), the reference
applies to the AT versions of that board.
The SC-2040 is a circuitboard assembly that is placed on a workbench or mounted in a 19-in.
rack. You can configure the SC-2040 to draw power from the MIO-16E board or from an
external +5 V supply. A red LED indicates when the board is powered on. Input signal leads are
attached at screw terminals.
What You Need to Get Started
To set up and use your SC-2040, you will need the following components:
• SC-2040 board
•SC-2040 User Manual
• 1.0, 2.0, 5.0, or 10.0 m SH6868 or R6868 cable
Detailed specifications of the SC-2040 are in Appendix A,Specifications.

Introduction Chapter 1
SC-2040 User Manual 1-2 © National Instruments Corporation
Software Programming Choices
Your SC-2040 kit does not include software. There are four options to choose from when
programming your National Instruments DAQ and SCXI hardware. You can use LabVIEW,
LabWindows, NI-DAQ, or register-level programming software.
The SC-2040 works with LabVIEW for Windows, LabVIEW for Macintosh, LabWindows for
DOS, LabWindows/CVI for Windows, NI-DAQ software for PC compatibles, and NI-DAQ
software for Macintosh.
LabVIEW and LabWindows Application Software
LabVIEW and LabWindows are innovative program development software packages for data
acquisition and control applications. LabVIEW uses graphical programming, whereas
LabWindows enhances traditional programming languages. Both packages include extensive
libraries for data acquisition, instrument control, data analysis, and graphical data presentation.
LabVIEW currently runs on three different platforms–AT/MC/EISA computers running
Microsoft Windows, the Macintosh platform, and the Sun SPARCstation platform. 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 DAQ hardware, is included with LabVIEW. The
LabVIEW Data Acquisition VI Libraries are functionally equivalent to the NI-DAQ software,
except that the SCXI functions are not included in the LabVIEW software for Sun.
LabWindows has two versions–LabWindows for DOS is for use on PCs running DOS, and
LabWindows/CVI is for use on PCs running Windows and for Sun SPARCstations.
LabWindows/CVI features interactive graphics, a state-of-the-art user interface, and uses the
ANSI standard C programming language. The LabWindows Data Acquisition Library, a series
of functions for using LabWindows with National Instruments DAQ hardware, is included with
the NI-DAQ software kit. The LabWindows Data Acquisition libraries are functionally
equivalent to the NI-DAQ software, except that the SCXI functions are not included in the
LabWindows/CVI software for Sun.
Using LabVIEW or LabWindows 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 is not packaged with SCXI or accessory products. 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.

Chapter 1 Introduction
© National Instruments Corporation 1-3 SC-2040 User Manual
NI-DAQ also internally addresses many of the complex issues between the computer and the
DAQ hardware 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. Figure 1-1 illustrates the relationship between NI-DAQ and
LabVIEW and LabWindows. You can see that the data acquisition parts of LabVIEW and
LabWindows are functionally equivalent to the NI-DAQ software.
LabWindows
(PC or
Sun SPARCstation)
LabVIEW
(PC, Macintosh, or
Sun SPARCstation)
Conventional
Programming
Environment
(PC, Macintosh, or
Sun SPARCstation)
NI-DAQ
Driver Software
DAQ or
SCXI Hardware Personal
Computer
or
Workstation
Figure 1-1. The Relationship between the Programming Environment,
NI-DAQ, and Your Hardware
The National Instruments PC, AT, MC, EISA, DAQCard, and DAQPad Series DAQ hardware is
packaged with NI-DAQ software for PC compatibles. NI-DAQ software for PC compatibles
comes with language interfaces for Professional BASIC, Turbo Pascal, Turbo C, Turbo C++,
Borland C++, and Microsoft C for DOS; and Visual Basic, Turbo Pascal, Microsoft C with SDK,
and Borland C++ for Windows. You can use your AT-MIO-16, together with other PC, AT,
MC, EISA, DAQCard, and DAQPad Series DAQ and SCXI hardware, with NI-DAQsoftware
for PC compatibles.
The National Instruments NB Series DAQ boards are packaged with NI-DAQ software for
Macintosh. NI-DAQ software for Macintosh comes with language interfaces for MPW C,
THINK C, Pascal, and Microsoft QuickBASIC. Any language that uses Device Manager
Toolbox calls can access NI-DAQ software for Macintosh. You can use NB Series DAQ boards
and SCXI hardware with NI-DAQ software for Macintosh.
The National Instruments SB Series DAQ boards are packaged with NI-DAQ software for Sun,
which comes with a language interface for ANSI C.

Introduction Chapter 1
SC-2040 User Manual 1-4 © National Instruments Corporation
Register-Level Programming
There are no register-level programming concerns for the SC-2040. When using the SC-2040,
only the MIO-16E Series board needs to be programmed. Refer to your MIO-16E board manual
for further information on register-level programming.
Optional Equipment
Contact National Instruments to order the following optional equipment:
• CB-50 I/O connector (50-screw terminals) with 0.5 or 1.0 m cable
• Single or double height rack-mount kit with acrylic plastic cover
• Single or double height rack-mount kit with metal wraparound cover
Unpacking
Your SC-2040 board is shipped in an antistatic package to prevent electrostatic damage to the
board. Electrostatic discharge can damage several components on the board. To avoid such
damage in handling the board, take the following precautions:
• Ground yourself via a grounding strap or by holding a grounded chassis such as a computer
chassis.
• Touch the antistatic package to a metal part of your computer chassis before removing the
board from the package.
• Remove the board from the package and inspect the board for loose components or any other
sign of damage. Notify National Instruments if the board appears damaged in any way.
Do not install a damaged board into your computer.
•Never touch the exposed pins of connectors.

© National Instruments Corporation 2-1 SC-2040 User Manual
Chapter 2
Configuration and Installation
This chapter describes the configuration and installation of your SC-2040. The topics discussed
are switch and jumper configuration, connection of the SC-2040 to the MIO-16E, and the power-
on sequence for your SC-2040 configuration.
Board Configuration
The SC-2040 has 10 jumpers, eight DIP switches, and one slide switch that you use to configure
the board. These switches and jumpers are shown in Figure 2-1.

Configuration and Installation Chapter 2
SC-2040 User Manual 2-2 © National Instruments Corporation
Figure 2-1. SC-2040 Parts Locator Diagram

Chapter 2 Configuration and Installation
© National Instruments Corporation 2-3 SC-2040 User Manual
The SC-2040 has one switch that controls whether the board is powered from an external supply
or from the MIO-16E board. Furthermore, two jumpers control how the board is shielded and
grounded. Additionally, there are eight sets of switches and jumpers that configure the gain
settings and input modes of the eight SC-2040 channels.
Table 2-1. Power Supply Selection
Switch Description Configuration
SW1
J13
INT position—Use this setting
to configure the SC-2040 to
draw power through the
MIO-16E board. (factory
setting)
SW1
INT
EXT
A. Internal
Power
EXT position—Use this
setting to draw +5 V power
from an external supply
connected to connector J13.
B. External
Power
SW1
INT
EXT

Configuration and Installation Chapter 2
SC-2040 User Manual 2-4 © National Instruments Corporation
Table 2-2. Shield Selection
Jumper Description Configuration
W1 SHLD OFF position—Place
the jumper in this position to
keep the SC-2040 analog
ground isolated from the metal
standoffs in the corners of the
board (factory setting).
W1
SHLD OFF
SHLD ON
SHLD ON position—Place
the jumper in this position to
connect the SC-2040 analog
ground to the metal standoffs
or to a rack-mount kit, which
may provide shielding for the
SC-2040.
W1
SHLD OFF
SHLD ON
Table 2-3. DAQ Board Ground Isolation Selection
Jumper Description Configuration
W10 AIGND-AIGND position—
Use this setting if you are
using a MIO-16E DAQ board.
Place the jumper in this
position to keep the SC-2040
digital ground and analog
grounds isolated (factory
setting).
DGND
AIGND
W10
AIGND
AIGND-DGND position—
Place the jumper in this
position to connect the
SC-2040 analog ground to
digital ground.
DGNDAIGND
W10
AIGND

Chapter 2 Configuration and Installation
© National Instruments Corporation 2-5 SC-2040 User Manual
Table 2-4. Channel Gain Selection
Switch Description Configuration
U2
U6
U9
U14
U17
U21
U24
U28
Gain Table
Unity gain position—For
unity gain (gain = 1), open all
the switches by pushing down
the OFF end of the switches.
(factory setting) OFF
1234
The unity gain position has
the number side up.
A B C D
Other gains—Refer to
Supplementary Configuration
Information, later in the
chapter, and the gain table on
the board itself.
Table 2-5. Channel Input Mode
Switch Description Configuration
W2
W3
W4
W5
W6
W7
W8
W9
A-B position—Use this
setting for connecting ground-
referenced signals to the
SC-2040 (factory setting).
W2
A B C
B-C position—Use this setting
for connecting floating (non-
ground referenced) sources.
A 100 kΩresistor is
connected from the negative
channel input to the SC-2040
analog ground.
W2
A B C
The W3–W9 jumper
positions are the same
as on W2.

Configuration and Installation Chapter 2
SC-2040 User Manual 2-6 © National Instruments Corporation
Supplementary Configuration Information
Power Supply Selection
Set switch SW1 to the INT position to connect the SC-2040 power converter to the +5 V lines on
the MIO-16E board. Set switch SW1 to the EXT position to draw power from an external +5 V
power supply connected to J13.
The MIO-16E is fused to provide 5 W of power (at +5 V and 1 A). The SC-2040 consumes
nearly all of this available power. Therefore, if you have other DAQ accessories that you would
like to power from the MIO, you should switch the SC-2040 to external power and provide an
external +5 V power source. In external power mode, the SC-2040 is fuse limited to 1 A at
+5 V.
Shield Selection
If you are using a rack-mount kit, shield the SC-2040 from unwanted noise by connecting the
analog ground on the board to the metal chassis of the rack using jumper W1. When you set W1
to the SHLD ON position, the jumper connects the analog ground to the metal standoffs used to
mount the board in a rack. In the SHLD OFF position, the SC-2040 analog ground is isolated
from the metal standoffs.
DAQ Board Ground Isolation Selection
You can use jumper W10 to connect the SC-2040 digital and analog grounds. If you are using a
MIO-16E board, you must isolate the grounds by leaving the jumper in its default position.
Gain Selection
The gain selection switches can select gains of 1, 10, 100, 200, 300, 500, 600, 700, and 800 for
each channel, as shown in Table 2-6.
Table 2-6. Gain Switches for Each Channel
Channel Close Switches
0U2
1U6
2U9
3 U14
4 U17
5 U21
6 U24
7 U28