National Instruments BNC-208X Series User manual

© Copyright 1991, 1994 National Instruments Corporation.
All Rights Reserved.
BNC-208X Series
User Manual
Analog BNC Breakout Boards
September 1993 Edition
Part Number 320407-01

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Limited Warranty
The BNC-208X Series boards 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 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
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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.
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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 BNC-208X Series User Manual
Preface
This manual describes the electrical and mechanical aspects of the BNC-2080 and
BNC-2081 boards and contains information about installing and making connections to the boards.
The BNC-208X Series boards are analog breakout boards with BNC-style connectors. These
breakout boards connect to the National Instruments multifunction data acquisition boards for the
IBM PC/XT/AT, Personal System/2, and compatible computers, and Macintosh NuBus computers.
Organization of This Manual
The BNC-208X Series User Manual is organized as follows:
• Chapter 1, Introduction, describes the BNC-208X Series boards; lists the contents of your
BNC-2080 and BNC-2081 kits; describes the optional equipment, signal conditioning
accessories, and software support; and explains how to unpack your BNC-208X Series board.
• Chapter 2, BNC-2080 Board,describes the BNC-2080 board in detail, including its function,
specifications, compatibility, connection, mounting, and application notes.
• Chapter 3, BNC-2081 Board, describes the BNC-2081 board in detail, including its function,
specifications, compatibility, connection, mounting, and application notes.
• Chapter 4, Installation and Connections, explains how to install and make connections to the
BNC-208X Series boards.
• TheCustomer Communication appendix contains forms you can use to request help from
National Instruments or to comment on our products.
• The Index contains an alphabetical list of key terms and topics in this manual, including the
page where you can find each one.
Conventions Used in This Manual
The following conventions are used in this manual:
italic Italic text denotes emphasis, a cross reference, or an introduction to a key
concept.
Lab board Lab board refers to the Lab-PC, Lab-PC+, Lab-NB, and Lab-LC boards.
Macintosh NuBus Macintosh NuBus refers to the Macintosh NuBus family of computers.
MIO-16 MIO-16 refers to the AT-MIO-16, AT-MIO-16D, AT-MIO-16F-5,
AT-MIO-16X, MC-MIO-16, NB-MIO-16, NB-MIO-16X, and
PC-LPM-16 boards.

Preface
BNC-208X Series User Manual vi © National Instruments Corporation
PC PC refers to PC/XT/AT/EISA and IBM PS/2 computers.
SC-205X SC-205X refers to the SC-2050, SC-2051, SC-2052, and SC-2053 boards.
SC-206X SC-206X refers to the SC-2060, SC-2061, and SC-2062 boards.
SC-207X SC-207X refers to the SC-2070, SC-2071, and SC-2072 boards.
Abbreviations
The following metric system prefixes are used with abbreviations for units of measure in this
manual:
Prefix Meaning Value
µ- micro- 10-6
m- milli- 10-3
k- kilo- 103
M- mega- 106
The following abbreviations are used in this manual:
A amperes
C Celsius
dB decibels
°degrees
F farads
fccutoff frequency
Hz hertz
in. inches
m meters
Ωohms
% percent
πpi
V volts
W watts
Acronyms
The following acronyms are used in this manual:
AC alternating current
CMRR common-mode rejection ratio
DC direct current
DGND digital ground
DIFF differential input
I/O input/output
LED light-emitting diode
NRSE nonreferenced single-ended input
RSE referenced single-ended input
VDC volts direct current

Preface
© National Instruments Corporation vii BNC-208X Series User Manual
Related Documentation
The following National Instruments documents contain information that you may find helpful as
you read this manual:
•SC-205X Series User Manual (part number 320385-01)
•SC-206X Series User Manual (part number 320200-01)
•SC-207X Series User Manual (part number 320239-01)
The following National Instruments documents may also be helpful to you depending on the type of
system you are using with your BNC-208X Series boards:
• Macintosh NuBus users
-NB-MIO-16X User Manual (part number 320157-01)
-NB-MIO-16 User Manual (part number 320295-01)
-Lab-NB User Manual (part number 320174-01)
• IBM PC/XT/AT users
-AT-MIO-16F-5 User Manual (part number 320266-01)
-AT-MIO-16 User Manual (part number 320476-01)
-Lab-PC User Manual (part number 320205-01)
-Lab-PC+ User Manual (part number 320502-01)
-PC-LPM-16 User Manual (part number 320287-01)
• IBM PS/2 Micro Channel users
-MC-MIO-16 User Manual (part number 320130-01)
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 the appendix at the end of this manual.

© National Instruments Corporation ix BNC-208X Series User Manual
Contents
Chapter 1
Introduction .........................................................................................................................1-1
What Your Kit Should Contain......................................................................................1-3
Optional Equipment.......................................................................................................1-3
Signal Conditioning Accessories...................................................................................1-4
Software Support............................................................................................................1-5
Unpacking......................................................................................................................1-5
Chapter 2
BNC-2080 Board ................................................................................................................2-1
Power Connections ........................................................................................................2-3
Analog Input...................................................................................................................2-3
Shield Ground................................................................................................................2-5
Fuse and Power LED.....................................................................................................2-6
Digital and Timing Signals............................................................................................2-6
Specifications.................................................................................................................2-6
Analog Input ......................................................................................................2-6
Power Requirements..........................................................................................2-7
Physical..............................................................................................................2-7
Operating Environment......................................................................................2-7
Storage Environment..........................................................................................2-7
Board-to-Board Cabling.................................................................................................2-7
Mounting........................................................................................................................2-9
Application Notes ..........................................................................................................2-9
Soldering and Desoldering on the BNC-2080 Board.........................................2-9
Channel Configurations.....................................................................................2-9
MIO-16 Analog Input............................................................................2-9
Connecting Nonreferenced (or Floating) Signal Sources..................................2-13
Differential Inputs..................................................................................2-13
Single-Ended Inputs...............................................................................2-14
Connecting Ground-Referenced Signal Sources................................................2-15
Differential Inputs..................................................................................2-15
Single-Ended Inputs...............................................................................2-15
Building Lowpass Filters...................................................................................2-15
Building Highpass Filters...................................................................................2-17
Building Attenuators (Voltage Dividers)...........................................................2-20
PC-LPM-16............................................................................................2-22
MIO-16 Analog Output..........................................................................2-23
Chapter 3
BNC-2081 Board.................................................................................................................3-1
Analog Input ..................................................................................................................3-2
Shield Ground................................................................................................................3-4
Fuse and Power LED.....................................................................................................3-5
Digital and Timing Signals............................................................................................3-5

Contents
BNC-208X Series User Manual x © National Instruments Corporation
Specifications.................................................................................................................3-5
Analog Input ......................................................................................................3-5
Power Requirements..........................................................................................3-5
Physical..............................................................................................................3-6
Operating Environment......................................................................................3-6
Storage Environment..........................................................................................3-6
Board-to-Board Cabling.................................................................................................3-6
Mounting........................................................................................................................3-8
Application Notes ..........................................................................................................3-8
Soldering and Desoldering on the BNC-2081 Board.........................................3-8
Connecting Nonreferenced (or Floating) Signal Sources..................................3-8
Connecting Ground-Referenced Signal Sources................................................3-8
Building Lowpass Filters...................................................................................3-9
Building Highpass Filters...................................................................................3-11
Building Attenuators (Voltage Dividers)...........................................................3-12
Lab Board Analog Output..............................................................................................3-14
Chapter 4
Installation and Connections..........................................................................................4-1
Hardware Installation.....................................................................................................4-1
Hardware Installation for the BNC-2080 and the BNC-2081............................4-1
Installing the SC-205X Series Cable Adapter Boards.......................................4-2
Installing the SC-207X General-Purpose Termination Breadboards.................4-2
Rack Mounting...................................................................................................4-2
External Power Connection (If Necessary)........................................................4-5
BNC-208X Series Board Connection................................................................4-6
Signal Connections ........................................................................................................4-7
Ribbon-Cable Connectors..................................................................................4-7
Rack-Mount Chassis Cover Attachment............................................................4-7
Appendix
Customer Communication...............................................................................................A-1
Index..................................................................................................................................Index-1
Figures
Figure 1-1. BNC-2080 Board Directly Connected to an MIO-16 Board............................1-2
Figure 1-2. BNC-208X, SC-207X, SC-206X, and SC-205X Series Boards
Connected to an MIO-16 Board.......................................................................1-2
Figure 2-1. BNC-2080 Analog Breakout Board..................................................................2-1
Figure 2-2. BNC-2080 Board Parts Locator Diagram.........................................................2-2
Figure 2-3. Onboard Equivalent Circuit for DIFF Mode....................................................2-4
Figure 2-4. W2 Jumper Settings..........................................................................................2-5
Figure 2-5. Direct Connection between an MIO-16 Board and the BNC-2080 Board.......2-8

Contents
© National Instruments Corporation xi BNC-208X Series User Manual
Figure 2-6. Connection between an MIO-16 Board, the BNC-2080 Board, and
the SC-2070/72 Board or the MIO-16, and the BNC-2080 and
SC-206X Series Boards via the SC-2050 Board..............................................2-8
Figure 2-7. Switch Configurations for Differential Mode or Single-Ended Mode.............2-10
Figure 2-8. W1 Ground Reference Jumper.........................................................................2-10
Figure 2-9. BNC-2080 Switch Configurations for an MIO-16 Configured in
DIFF Mode (Factory Default Setting)..............................................................2-11
Figure 2-10. BNC-2080 Switch Configurations for an MIO-16 Configured in
RSE and NRSE Modes.....................................................................................2-12
Figure 2-11. Bias Return Resistor for DC-Coupled Floating Source on Channel 1
in DIFF Mode...................................................................................................2-14
Figure 2-12. Normalized Frequency Response of Lowpass Filter........................................2-16
Figure 2-13. Lowpass Filter on Differential Channel 1........................................................2-17
Figure 2-14. Normalized Frequency Response of Highpass Filter.......................................2-18
Figure 2-15. Highpass Filter on Differential Channel 1........................................................2-19
Figure 2-16. Attenuator for Use with Differential Inputs......................................................2-21
Figure 2-17. Switch Configurations for SE Mode (PC-LPM-16).........................................2-22
Figure 2-18. Ground Reference Jumper Position for Use with the PC-LPM-16..................2-23
Figure 2-19. Analog Output Schematic for DACs, DAC0 OUT Shown.............................2-23
Figure 3-1. BNC-2081 Analog Breakout Board..................................................................3-1
Figure 3-2. BNC-2081 Board Parts Locator Diagram.........................................................3-2
Figure 3-3. Onboard Equivalent Circuit..............................................................................3-3
Figure 3-4. W1 Jumper Settings..........................................................................................3-4
Figure 3-5. Direct Connection between a Lab Board and the BNC-2081 Board................3-7
Figure 3-6. Connection between a Lab Board, the BNC-2081, and the SC-2071 Board,
or the Connection between a Lab Board, the BNC-2081 and the SC-206X
Series Board, via the SC-2053 Board...............................................................3-7
Figure 3-7. Normalized Frequency Response of Lowpass Filter........................................3-9
Figure 3-8. Lowpass Filter on Channel 1............................................................................3-10
Figure 3-9. Normalized Frequency Response of Highpass Filter.......................................3-11
Figure 3-10. Highpass Filter on Channel 1 ...........................................................................3-12
Figure 3-11. Attenuator for Use with BNC-2081 Board Inputs............................................3-13
Figure 3-12. DAC0 OUT Schematic.....................................................................................3-14
Figure 3-13. Analog Output Schematic for DACs, DAC0 OUT Shown.............................3-14
Figure 4-1. Mounting Locations for the BNC-208X Series Board and SC-207X
Series Board......................................................................................................4-3
Figure 4-2. Mounting Locations for the BNC-208X Series Board and SC-205X
Series Board or SC-206X Series Board............................................................4-3
Figure 4-3. Attaching a Mountable Board to the Chassis ...................................................4-4
Figure 4-4. Double-Height Mounting..................................................................................4-5
Figure 4-5. Connections between Data Acquisition Boards and BNC-208X
Series Boards and between SC-205X Series Boards and BNC-2080
and BNC-2081 Boards......................................................................................4-6

Contents
BNC-208X Series User Manual xii © National Instruments Corporation
Tables
Table 1-1. Data Acquisition Boards for Use with BNC-208X Series Boards...................1-1
Table 2-1 Switch S5 Settings for National Instruments Data Acquisition Boards...........2-3
Table 2-2. DIFF Mode Channel Component Positions......................................................2-5
Table 2-3. Data Acquisition Boards Used with the BNC-2080 Board..............................2-7
Table 3-1. Component Positions in Each Channel.............................................................3-4
Table 3-2. Data Acquisition Boards Used with the BNC-2081 Board..............................3-6

© National Instruments Corporation 1-1 BNC-208X Series User Manual
Chapter 1
Introduction
This chapter describes the BNC-208X Series boards; lists the contents of your BNC-2080 and BNC-
2081 kits; describes the optional equipment, signal conditioning accessories, and software support; and
explains how to unpack your BNC-208X Series board.
The BNC-2080 and BNC-2081 boards are two analog breakout boards with signal-labeled BNC
connectors and analog signal conditioning areas. The BNC-2080 and BNC-2081 breakout boards
simplify the connection of analog signals, some digital signals, and two user-defined connections to the
data acquisition board in laboratory, test, and production environments. The BNC-2080 can be
configured to use 8 differential or 16 single-ended analog input channels available on the board. The
boards have silkscreened component locations for resistors, and capacitors for building single-pole
highpass and lowpass filters, and voltage dividers.
Table 1-1 lists the specific data acquisition boards that can currently be used with the BNC-208X Series
boards.
Table 1-1. Data Acquisition Boards for Use with BNC-208X Series Boards
NB Series
(Macintosh
NuBus)
MC Series
(IBM PS/2) PC and AT Series
(PC/XT/AT)
Lab Series
(PC/XT/AT and
Macintosh
NuBus)
BNC-2080 NB-MIO-16
NB-MIO-16X MC-MIO-16 AT-MIO-16 AT-MIO-16D
AT-MIO-16F-5
AT-MIO-16X
PC-LPM-16
BNC-2081 Lab-LC
Lab-NB
Lab-PC
Lab-PC+
Note: When a board is referred to as an MIO-16 board, the reference applies to the AT-MIO-16,
AT-MIO-16D, AT-MIO-16F-5, AT-MIO-16X, MC-MIO-16, NB-MIO-16, NB-MIO-16X,
and PC-LPM-16 boards listed in Table 1-1. Similarly, when a board is referred to simply as a
Lab board, the reference applies to the Lab-LC, Lab-NB, Lab-PC+ and Lab-PC boards listed in
Table 1-1.
All analog signals from the data acquisition board are made available at BNC connectors. Each of the
BNC-208X Series boards is connected directly to the data acquisition board (NB, MC, Lab, PC, or
AT Series) by a 50-pin ribbon cable. The AT-MIO-16D requires an NB5 cable. The Lab-LC requires
an NB10 cable. If any SC-206X Series digital signal conditioning boards are also being used with the
same data acquisition board for conditioning of the digital I/O signals, then an SC-205X Series cable
adapter board is required.

Introduction Chapter 1
BNC-208X Series User Manual 1-2 © National Instruments Corporation
Figure 1-1 shows the BNC-2080 board mounted in a 19-in. rack mount, directly connected to the MIO-
16 data acquisition board.
Figure 1-1. BNC-2080 Board Directly Connected to an MIO-16 Board
The BNC-208X Series boards can be mounted beside an SC-205X Series cable adapter board, an SC-
206X Series signal conditioning board, and an SC-207X Series general-purpose termination breadboard
in a 19-in. rack-mount chassis. You can mount your BNC-208X Series board on the left or right side of
the rack mount. Mounting the BNC-208X Series board on the left side and running the cable under the
BNC-208X Series board to connect to the any of the SC Series boards will make access to both boards
easier. Figure 1-2 shows the BNC-208X, SC-207X, SC-206X, and SC-205X Series boards connected
to an MIO-16 board.
Figure 1-2. BNC-208X, SC-207X, SC-206X, and SC-205X Series Boards
Connected to an MIO-16 Board
Art not available in PDF version of this document.
Art not available in PDF version of this document.

Chapter 1 Introduction
© National Instruments Corporation 1-3 BNC-208X Series User Manual
What Your Kit Should Contain
There are three kit versions for each of the BNC-2080 and the BNC-2081 boards–one kit contains a 0.5
m cable, one kit contains a 1.0 m cable, and one kit contains no cable, listed as follows.
Kit Name Kit Part
Number Kit Component Board Part Number
BNC-2080 kit with 0.5 m
cable 776579-05 BNC-2080 board 50-conductor 0.5 m NB1 cable 181630-01 180524-05
BNC-2080 kit with 1.0 m
cable 776579-10 BNC-2080 board 50-conductor 1.0 m NB1 cable 181630-01 180524-10
BNC-2080 without cable 776579-90 BNC-2080 board 181630-01
BNC-2081 kit with 0.5 m
cable 776599-05 BNC-2081 board 50-conductor 0.5 m NB1 cable 181635-01 180524-05
BNC-2081 kit with 1.0 m
cable 776599-10 BNC-2081 board 50-conductor 1.0 m NB1 cable 181635-01 180524-10
BNC-2081 without cable 776599-90 BNC-2081 board 181635-01
You can identify which version of the BNC-208X Series kit you have by looking up the part number in
the preceding table.
In addition to the board, each version of the BNC-208X Series kit contains the following component.
Kit Component Part Number
BNC-208X Series User Manual 320407-01
If your kit is missing any of the components or if you received the wrong version, contact National
Instruments.
Optional Equipment
Equipment Part Number
Type NB5 cable (for the AT-MIO-16D)
0.5 m 181304-05
1.0 m 181305-05
Rack-mount chassis kit with acrylic plastic cover
Single height 180636-01
Double height 180636-02
Rack-mount chassis kit with metal wraparound cover
Single height 181080-01
Double height 181080-02

Introduction Chapter 1
BNC-208X Series User Manual 1-4 © National Instruments Corporation
Signal Conditioning Accessories
Accessory Part Number
SSR Series eight-channel backplane
with 0.4 m cable for SC-2050 Series
SC-2070 and 50-conductor cable
0.5 m cable
1.0 m cable
SC-2071 and 50-conductor cable
0.5 m cable
1.0 m cable
SC-2072 and 50-conductor cable
0.5 m cable
1.0 m cable
SC-2072D and 50-conductor cable
0.5 m cable
1.0 m cable
SC-2060 and 26-conductor cable
0.2 m cable
0.4 m cable
SC-2061 and 26-conductor cable
0.2 m cable
0.4 m cable
SC-2062 and 26-conductor cable
0.2 m cable
0.4 m cable
SC-2050 and 50-conductor cable
0.5 m cable
1.0 m cable
SC-2051 and 50-conductor cable
0.5 m cable
1.0 m cable
SC-2052 and 50-conductor cable
0.5 m cable
1.0 m cable
SC-2053 and 50-conductor cable
0.5 m cable
1.0 m cable
776290-18
776358-00
776358-10
776358-01
776358-11
776358-02
776358-12
776358-102
776358-112
776336-00
776336-10
776336-01
776336-11
776336-02
776336-12
776335-00
776335-10
776335-01
776335-11
776335-02
776335-12
776335-03
776335-13

Chapter 1 Introduction
© National Instruments Corporation 1-5 BNC-208X Series User Manual
Software Support
The BNC-208X Series boards require no additional software support beyond that provided for the data
acquisition board in use.
Unpacking
Your BNC-208X Series board is shipped in an antistatic package to prevent electrostatic damage to the
board. Several components on the board can be damaged by electrostatic discharge. To avoid such
damage in handling the board, take the following precautions:
• 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.

© National Instruments Corporation 2-1 BNC-208X Series User Manual
Chapter 2
BNC-2080 Board
This chapter describes the BNC-2080 board in detail, including its function, specifications, compatibility,
connection, mounting, and application notes.
The BNC-2080 is an analog breakout board that makes it easy to connect to all MIO-16 or
PC-LPM-16 analog signals and a few digital signals via BNC connectors. All other MIO-16 signals are
accessible via solder holes in the board next to data acquisition board input connectors. Passive analog
input signal conditioning, such as filters and dividers, can also be added.
The BNC-2080 board is used with the National Instruments data acquisition boards for the Macintosh
NuBus (NB Series), IBM PS/2 Micro Channel (MC Series), and PC/XT/AT and compatible computers.
Figure 2-1 shows the BNC-2080 board.
Figure 2-1. BNC-2080 Analog Breakout Board
The BNC-2080 board has BNC connectors for all analog signals, a few digital signals, and two user-
defined connectors. With open component positions in the input paths, you can insert resistors and
capacitors for conditioning the 16 single-ended or 8 differential analog input signals. The BNC-208X
Series boards can also be used in conjunction with the other signal conditioning accessories, including
the SC-207X Series boards. For connection of multiple signal conditioning accessories, an SC-205X
Series cable adapter board must be used.
Art not available in PDF version of this document.

BNC-2080 Board Chapter 2
BNC-208X Series User Manual 2-2 © National Instruments Corporation
Figure 2-2 illustrates the parts locator diagram for the BNC-2080 board.
Figure 2-2. BNC-2080 Board Parts Locator Diagram
Art not available in PDF version of this document.

Chapter 2 BNC-2080 Board
© National Instruments Corporation 2-3 BNC-208X Series User Manual
Power Connections
Because the BNC-2080 board is an analog breakout board for both the MIO-16 and PC-LPM-16 boards,
it has a flexible power connection scheme.
Switch S5 is responsible for selecting the power inputs from the I/O cable. Switch S5 is a three-position
switch that configures the BNC-2080 to connect to pins 33 (DGND) and 34 (+5 V) in position A, to no
I/O pins in position B, and to pins 49 (+5 V) and 50 (DGND) in position C.
Table 2-1 shows the setting to be used with each of the National Instruments data acquisition boards.
Table 2-1. Switch S5 Settings for National Instruments Data Acquisition Boards
Board S5 Setting
AT-MIO-16
AT-MIO-16D
AT-MIO-16F-5
AT-MIO-16X
A
A
A
A
MC-MIO-16 A
NB-MIO-16
NB-MIO-16X
PC-LPM-16
A
A
C
Warning: If the data acquisition board does not use pins 33/34 or pins 49/50 for power connections,
set switch S5 to position B. Failure to set switch S5 to position Bunder these conditions
could result in damage to your external power supply, the
BNC-2080, the expansion board connected to the BNC-2080, and/or your computer.
National Instruments is not liable for damages resulting from such connections.
Analog Input
Each differential analog input has seven open positions for signal conditioning components. Six of these
positions are designated as resistors, and one is designated as a capacitor. The board is shipped with
jumpers in two positions for each input. The equivalent circuit of one input is shown in Figure 2-3. The
board can be used when the MIO-16 board is configured for both 16 single-ended inputs and 8
differential inputs. For specific applications illustrating signal conditioning with both single-ended and
differential inputs, refer to the section titled Application Notes later in this chapter.

BNC-2080 Board Chapter 2
BNC-208X Series User Manual 2-4 © National Instruments Corporation
ACH 9
(-in) ACH 1 (+in)
BNC Connector
Case Channel 1
(Center)
To Input
Multiplexer
on MIO-16
Input Schematic forACH1 (DIFF mode)
BNC Connector
32 1
Channel 9
(Center) Case
COMMON
DIFF SE
+5 V +5 V
AIGND AIGND
R21
R15
R20
R4
R11
R3
C2
C
D
A
B
E
F
G
S2
AIGND
AISENSE 1
2
3
NRSE
RSE
Jumpers Installed
Here at Factory
W1
Figure 2-3. Onboard Equivalent Circuit for DIFF Mode
The components are numbered differently for each channel. Table 2-2 lists the components in each
channel and their correspondence to the circuit shown in Figure 2-3.