DAQ BNC-2090 User Guide

BNC-2090 User Manual

Rack-Mount BNC Accessory

March 1996 Edition

Part Number 321183A-01



Copyright 1996 National Instruments Corporation. All Rights Reserved.

Internet Support

GPIB:

[e-mail]

DAQ:

[e-mail]

VXI:

[e-mail]

LabVIEW:
LabWindows:
HiQ:

[e-mail]

[e-mail]

[e-mail]

E-mail:
FTP Site:
Web Address:

[e-mail]

ftp.natinst.com

http://www.natinst.com

Bulletin Board Support

BBS United States: [phone] or [phone]
BBS United Kingdom: 01635 551422
BBS France: 1 48 65 15 59

FaxBack Support

[phone]

Telephone Support (U.S.)

Tel: [phone]
Fax: [phone]

International Offices

Australia 03 9 879 9422, Austria 0662 45 79 90 0, Belgium 02 757 00 20,
Canada (Ontario) 519 622 9310, Canada (Québec) 514 694 8521, Denmark 45 76 26 00,
Finland 90 527 2321, France 1 48 14 24 24, Germany 089 741 31 30, Hong Kong 2645 3186,
Italy 02 413091, Japan 03 5472 2970, Korea 02 596 7456, Mexico 95 800 010 0793,
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Sweden 08 730 49 70, Switzerland 056 200 51 51, Taiwan 02 377 1200, U.K. 01635 523545

National Instruments Corporate Headquarters

6504 Bridge Point Parkway Austin, TX 78730-5039 Tel: [phone]

Important Information

Warranty

The BNC-2090 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.

XCEPT AS SPECIFIED HEREIN

E

SPECIFICALLY DISCLAIMS ANY WARRANTY OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE

C

USTOMER’S RIGHT TO RECOVER DAMAGES CAUSED BY FAULT OR NEGLIGENCE ON THE PART OF NATIONAL

I

NSTRUMENTS SHALL BE LIMITED TO THE AMOUNT THERETOFORE PAID BY THE CUSTOMER
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

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.

, N

ATIONAL INSTRUMENTS MAKES NO WARRANTIES, EXPRESS OR IMPLIED, AND

.

. N

ATIONAL INSTRUMENTS

. This limitation of the liability of National

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

Product 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.

About This Manual

Organization of This Manual ........................................................................................ix

Conventions Used in This Manual ................................................................................x

Related Documentation .................................................................................................x

Customer Communication ............................................................................................xi

Chapter 1
Introduction

About the BNC-2090 ....................................................................................................1-1

What You Need to Get Started ......................................................................................1-1

Optional Equipment ......................................................................................................1-2

Chapter 2
Configuration, Installation, and Signal Connection

Configuring Your BNC-2090 .......................................................................................2-1

Mode Configuration ........................................................................................2-2

DIFF Input Mode .............................................................................2-2

RSE and NRSE Input Mode .............................................................2-2

Power Selection Switch ..................................................................................2-3

Shield Ground Jumper ....................................................................................2-3

Signal Conditioning Jumpers ..........................................................................2-5

Installing Your BNC-2090 ............................................................................................2-6

Accessory-to-Board Cabling ..........................................................................2-7

Connecting Your Signals ..............................................................................................2-9

Connecting Analog Inputs ..............................................................................2-11

Connecting Nonreferenced (or Floating) Signal Sources ................2-11

DIFF Inputs ........................................................................2-11

SE Inputs ............................................................................2-12

Connecting Ground-Referenced Signal Sources ..............................2-12

DIFF Inputs ........................................................................2-12

SE Inputs ............................................................................2-12

Connecting Analog Outputs ...........................................................................2-13

Connecting Digital I/O Signals .......................................................................2-13

Table of Contents

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National Instruments Corporation v BNC-2090 User Manual

Table of Contents

Chapter 3
Signal Conditioning Application Examples

Adding Signal Conditioning Components .................................................................... 3-1

Soldering and Desoldering on the BNC-2090 ............................................... 3-3

Analog Input ................................................................................................................. 3-3

Building Lowpass Filters ............................................................................... 3-5

Building Highpass Filters ............................................................................... 3-6

Building Attenuators (Voltage Dividers) ....................................................... 3-8

Analog Output .............................................................................................................. 3-10

Building Lowpass Filters ............................................................................... 3-11

Building Highpass Filters ............................................................................... 3-12

Appendix A
Specifications

Appendix B
Using the PC-LPM-16

Appendix C
Customer Communication

Glossary
Index

BNC-2090 User Manual vi

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National Instruments Corporation

Figures

Figure 2-1. BNC-2090 Rack-Mount Breakout Accessory ...................................... 2-1

Figure 2-2. BNC-2090 Front-Panel Switch Configurations .................................... 2-3

Figure 2-3. Accessing Jumper W1 .......................................................................... 2-5

Figure 2-4. Direct Connection of an MIO Board to the BNC-2090 ........................ 2-8

Figure 2-5. Connection between the DAQ Board, the BNC-2090

Figure 2-6. Bias Return Resistor for DC-Coupled Floating Source

Figure 2-7. Analog Output Schematic for DACs .................................................... 2-13

Figure 3-1. Disassembly of the BNC-2090 ............................................................. 3-2

Figure 3-2. Onboard Equivalent Circuit for DIFF Mode ........................................ 3-4

Figure 3-3. Normalized Frequency Response of Lowpass Filter ............................ 3-5

Figure 3-4. Lowpass Filter on Differential Channel 1 ............................................ 3-6

Figure 3-5. Normalized Frequency Response of Highpass Filter ........................... 3-7

Figure 3-6. Highpass Filter on Differential Channel 1 ............................................ 3-8

Figure 3-7. Attenuator for Use with Differential Inputs .......................................... 3-9

Figure 3-8. DAC0OUT and DAC1OUT ................................................................. 3-11

Figure 3-9. Lowpass Filter on DAC0OUT .............................................................. 3-12

Figure 3-10. Highpass Filter on DAC0OUT ............................................................. 3-12

Table of Contents

and SC-20XX Boards ........................................................................... 2-9

on Channel 1 in DIFF Mode ................................................................ 2-11

Figure B-1. Switch Configurations for RSE Mode (PC-LPM-16) .......................... B-1

Tables

Table 2-1. Jumper W1 Settings .............................................................................. 2-4

Table 2-2. BNC-2090 Cabling Options ................................................................. 2-7

Table 2-3. BNC-2090 Front Panel Labels ............................................................. 2-9

Table 3-1. Channel Component Positions .............................................................. 3-3

Table B-1. BNC-2090 Front Panel Labels and

Corresponding Signal Names for PC-LPM-16 ..................................... B-2

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National Instruments Corporation vii BNC-2090 User Manual

The

BNC-2090 User Manual

operation of the BNC-2090 accessory. The BNC-2090 is a rack-mount
analog breakout accessory with BNC-style connectors and spring-type
terminal blocks. This accessory connects to the National Instruments
MIO and PC-LPM-16 data acquisition (DAQ) boards for the IBM
PC/XT/AT and compatible computers, Macintosh NuBus and
compatible computers, PCI compatible computers, Sun SPARCstation
SBus computers, and NEC PC-9800 Series computers.

Organization of This Manual

The

BNC-2090 User Manual

• Chapter 1,
what you need to get started, and describes the optional equipment.

• Chapter 2,
explains how to configure the switches and jumper on the
BNC-2090, install the BNC-2090, and connect signals to the
accessory.

• Chapter 3,
instructions for adding signal conditioning components to your
BNC-2090 and contains signal conditioning examples for the
BNC-2090 in use with the MIO boards.

• Appendix A,
BNC-2090.

• Appendix B,
the PC-LPM-16 with the BNC-2090.

• Appendix C,
use to request help from National Instruments or to comment on
our products and manuals.

• The
used in this manual, including abbreviations, acronyms, metric
prefixes, mnemonics, and symbols.

• The
this manual, including the page where you can find each one.

Introduction

Configuration, Installation, and Signal Connection

Signal Conditioning Application Examples

Specifications

Using the PC-LPM-16

Customer Communication

Glossary

Index

contains an alphabetical list and description of terms

contains an alphabetical list of key terms and topics in

About This Manual

describes the features, functions, and

is organized as follows:

, describes the BNC-2090 accessory, lists

,

, contains

, lists the specifications for the

, contains information on using

, contains forms you can



National Instruments Corporation ix BNC-2090 User Manual

About This Manual

Conventions Used in This Manual

The following conventions are used in this manual:

< > Angle brackets, containing numbers separated by an ellipsis, represent

a range of values associated with a bit or signal name (for example,
ACH<0..7> stands for ACH0 through ACH7).

bold

italic

bold italic

DAQ Refers to the National Instruments data acquisition products.
MIO Refers to the National Instruments 100-pin, 68-pin, and 50-pin MIO

SC-205

SC-206

SC-207

X

X

X

Bold text denotes menus, menu items, or dialog box buttons or options.
Italic text denotes emphasis, a cross reference, or an introduction to a

key concept.
Bold italic text denotes a note, caution, or warning.

Series boards.
Refers to the National Instruments SC-2050, SC-2051, SC-2052,

SC-2053, SC-2054, SC-2055, and SC-2056 boards.
Refers to the National Instruments SC-2060, SC-2061, and SC-2062

boards.
Refers to the National Instruments SC-2070, SC-2071, and SC-2072

boards.

Abbreviations, acronyms, metric prefixes, mnemonics, symbols, and
terms are listed in the

Related Documentation

The following documents contain information that you may find
helpful as you read this manual:

• Your MIO or PC-LPM-16 board user manual

• SC-205X Series User Manual

• SC-206X Series User Manual

• SC-207X Series User Manual

BNC-2090 User Manual x

Glossary

.



National Instruments Corporation

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 C,

Customer Communication

About This Manual

, at the end of this manual.



National Instruments Corporation xi BNC-2090 User Manual

Chapter

Introduction

This chapter describes the BNC-2090 accessory, lists what you need to
get started, and describes the optional equipment.

About the BNC-2090

The BNC-2090 accessory is a rack-mount analog breakout accessory
with signal-labeled BNC connectors, spring terminal blocks, and analog
signal conditioning areas. The BNC-2090 accessory simplifies the
connection of analog signals and digital signals to the DAQ board for
use in laboratory, test, and production environments. You can configure
the BNC-2090 to use eight differential or 16 single-ended analog input
channels available on the accessory. The BNC-2090 has silkscreened
component locations for resistors and capacitors for building single­pole highpass and lowpass filters and voltage dividers.

You can use the BNC-2090 with a 50, 68, or 100-pin MIO DAQ board
or a 50-pin PC-LPM-16 DAQ board. Refer to Appendix B,

PC-LPM-16

BNC-2090.

1

Using the

, for information on using the PC-LPM-16 with the

What You Need to Get Started

To set up and use your BNC-2090 accessory, you will need the
following:

❑

BNC-2090 accessory

❑

BNC-2090 User Manual

❑

One of the following DAQ boards and the appropriate cable
50-pin MIO board (requires SH6850 or R6850 cable)
68-pin MIO board (requires SH6868 or R6868 cable)
100-pin MIO board (requires SH1006868 cable)
PC-LPM-16 DAQ board (requires SH6850 or R6850 cable)



National Instruments Corporation 1-1 BNC-2090 User Manual

Chapter 1 Introduction

❑

Screwdrivers (Phillips and flathead)
Four adhesive rubber feet (optional)

❑

Detailed specifications for the BNC-2090 are in Appendix A,

Specifications

Optional Equipment

You can also use the following National Instruments products with your
BNC-2090, including cables, connector blocks, and other accessories:

• SSR Series 8-channel backplane (with 0.4 m cable for the SC-205X
Series boards)

• SC-2050, SC-2051, or SC-2055 board (with 0.5 or 1.0 m 50-pin
cable)

• SC-2056 board (without cable)

• SC-2060, SC-2061, or SC-2062 (with 0.2 or 0.4 m 50-pin cable)

• SC-2070, SC-2072, or SC-2072D (with 0.5 or 1.0 m 50-pin cable)

.

BNC-2090 User Manual 1-2

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National Instruments Corporation

Configuration, Installation,

Chapter

and Signal Connection

This chapter explains how to configure the switches and jumper on the
BNC-2090, install the BNC-2090, and connect signals to the accessory.

Configuring Your BNC-2090

Your BNC-2090 is factory-configured. However, you must reconfigure
your accessory if you want to do any of the following:

• Use your BNC-2090 with a MIO board configured for RSE or
NRSE mode

• Connect the BNC-2090 shield directly to digital ground (DGND)

• Use a PC-LPM-16 as the BNC-2090 power source

• Condition your signals (Refer to Chapter 3,

Application Examples

Figure 2-1 shows the front and back panels of the BNC-2090.

1 2 3 4

2

Signal Conditioning

)

Front Panel

Rear Panel

5 3

1 SW1
4 Spring Terminal Blocks

Figure 2-1.

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National Instruments Corporation 2-1 BNC-2090 User Manual

2 SW9
5 Power Switch

BNC-2090 Rack-Mount Breakout Accessory

3 68-Position Connector

Chapter 2 Configuration, Installation, and Signal Connection

Mode Configuration

The BNC-2090 is factory-configured for use with the MIO board in the
DIFF mode. Therefore, you must configure the BNC-2090 if you want
to use the accessory with the MIO board in either RSE or NRSE mode.
The BNC-2090 has nine front panel switches, shown in Figure 2-1, that
configure the accessory for differential (DIFF), referenced single-ended
(RSE), or nonreferenced single-ended (NRSE) mode.

If you want to measure floating signal sources, configure the MIO board
for DIFF or NRSE mode, both of which require bias resistors, or for
RSE mode. Refer to Chapter 3,

Examples

If you want to measure ground-referenced signal sources, configure the
MIO board for the NRSE mode or DIFF mode. Both types of signal
sources are discussed in the following sections.

If you configure the MIO board in the RSE mode, all 16 analog input
channels are referenced to AIGND. For more information on the input
configurations, see your MIO board user manual.

, for information on installing bias resistors.

Signal Conditioning Application

DIFF Input Mode

The BNC-2090 is factory-configured for DIFF mode so that all eight
switches (SW1–SW8) are in the DIFF position. In DIFF mode, the first
eight analog BNC connectors (ACH<0..7>) are used and the remaining
eight analog BNC connectors (ACH<8..15>) are not used. (BNC-2090
switch SW9 position is irrelevant in this mode.) Make sure that your
MIO board is configured for DIFF input mode.

Note:

All of the switches are required to be in the same position; that is, S1
through S8 must all be in either the DIFF position or in the SE position.

RSE and NRSE Input Mode

First, configure the MIO board for RSE or NRSE input mode. Next,
configure the BNC-2090 for SE mode by flipping all eight switches
(SW1–SW8) next to each pair of BNC connectors to SE to have 16
single-ended channels. In this mode, all 16 BNC connectors are in use
and all 16 BNC shields are tied to a common signal. You can switch the
common signal between AIGND and AISENSE through switch SW9.
AISENSE is tied to a common signal for NRSE mode configuration and
AIGND is tied to a common signal for RSE mode configuration.

BNC-2090 User Manual 2-2

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National Instruments Corporation

Chapter 2 Configuration, Installation, and Signal Connection

Figure 2-2 shows the BNC-2090 front panel switches configured for
DIFF, RSE, and NRSE modes.

Power Selection Switch

The BNC-2090 has a power switch on the rear panel, shown in
Figure 2-1. If you use an MIO DAQ board, slide this switch to the MIO
position. If you use a PC-LPM-16 DAQ board, slide this switch to the
LPM-16 position.

ACH0

ACH1

SE

SE

DIFF

ACH9

ACH8

ACH0

ACH1

SE

SE

DIFF

ACH9

ACH8

ACH0

ACH1

SE

SE

DIFF

ACH9

ACH8

— switch in SE or RSE mode

Figure 2-2.

BNC-2090 Front-Panel Switch Configurations

ACH2

ACH3

SE

SE SE

DIFFDIFF

DIFF

ACH10

DIFF

ACH11

ACH4

ACH12

ACH5

SE

DIFF

ACH13

DIFF (Factory-Default Setting)

ACH2

ACH3

SE

SE SE

DIFFDIFF

DIFF

ACH10

DIFF

ACH11

ACH4

ACH12

ACH5

SE

DIFF

ACH13

RSE

ACH2

ACH3

SE

SE SE

DIFFDIFF

DIFF

ACH10

DIFF

ACH11

ACH4

ACH12

ACH5

SE

DIFF

ACH13

NRSE

ACH6

SE SE

DIFF DIFF

ACH14

SW9 irrelevant in

DIFF mode

ACH6

SE SE

DIFF DIFF

ACH14

ACH6

SE SE

DIFF DIFF

ACH14

ACH7

ACH15

ACH7

ACH15

ACH7

ACH15

R
S
E

N
R
S
E

R
S
E

N
R
S
E

R
S
E

N
R
S
E

DAC0OUT

DAC1OUT

DAC0OUT

DAC1OUT

DAC0OUT

DAC1OUT

Shield Ground Jumper

Jumper W1, located inside the BNC-2090 near the power switch,
connects the shield of the 68-position connectors and BNC-2090 metal
case

through

shows your configuration options.



National Instruments Corporation 2-3 BNC-2090 User Manual

a 100 Ω resistor to DGND or

directly

to DGND. Table 2-1

Chapter 2 Configuration, Installation, and Signal Connection

R1
100 Ω

R1
100 Ω

Table 2-1.

Configuration

100 Ω TO GND

SHIELD

GND

100 Ω TO GND

SHIELD

GND

W1

Digital

Ground

W1

Jumper W1 Settings

Description

100 Ω to Ground—Use this
setting to reduce any potential
ground loop current, thereby
improving the system noise
performance. (When the BNC­2090 is rack-mounted, it will be
connected to a different ground.)
This is the factory-default setting.

GND—Use this setting when the
BNC-2090 metal case is neither
connected to any other ground via
a rack mount nor connected to the
MIO ground via a shielded cable
such as the SH6868. (Use this
setting when you use the R6868,
R6850, or SH6850 cable.)

R1
100 Ω

BNC-2090 User Manual 2-4

100 Ω TO GND

SHIELD

GND

Digital

Ground

W1

Digital

Ground

You can also disconnect the
shield from the MIO ground by
removing the jumper from W1,
which prevents the ground loop
current from being carried in the
DGND return of the shielded
cable. This option is best for
rack-mount configurations
where the BNC-2090 metal case
is already grounded.

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National Instruments Corporation

Chapter 2 Configuration, Installation, and Signal Connection

To access and reconfigure jumper W1, perform the steps below.
Figure 2-3 shows the parts of the BNC-2090 you must remove.

NATIONAL
INSTR MUENTS

BNC-2090

4

3

2

1

1 Front Panel

Screws

2 Rear Panel Screws 3 Side Panel Screw 4 Jumper W1

Figure 2-3.

Accessing Jumper W1

1. Remove the six front panel screws.

2. Remove one side panel screw.

3. Remove two rear panel screws.

4. Hold the front panel and slide the unit out of the metal case.

5. Set jumper W1 as needed.

6. Reassemble the BNC-2090 in reverse order.

Signal Conditioning Jumpers

If you want to condition your input signals, you may have to remove the
0 Ω jumpers on the PWB behind the front panel (refer to Figure 3-1). If
you do not need signal conditioning, leave these jumpers in their

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National Instruments Corporation 2-5 BNC-2090 User Manual

Chapter 2 Configuration, Installation, and Signal Connection

factory-default settings. Refer to Chapter 3,

Application Examples

Installing Your BNC-2090

Perform the following steps to connect your BNC-2090 to your DAQ
system. Consult your computer user manual or technical reference
manual for specific instructions and warnings.

1. Determine what signal conditioning you need for analog inputs and
install the necessary components into the open component
positions. Refer to

Application Examples

2. Make sure that jumper W1 and switches SW1–SW9 are set
correctly for your current application.

3. Select the power source for the BNC-2090 by sliding the power
switch, located on the rear panel of the BNC-2090, to select the
DAQ board you are using (MIO or PC-LPM-16).

4. (Optional) You can mount the BNC-2090 into a 19 in. rack or place
the accessory on a workbench near the host computer. If you do not
rack-mount the accessory, you can use the four adhesive rubber feet
included in the BNC-2090 kit to keep the accessory stationary on
your workbench.

5. Connect the BNC-2090 to the DAQ board. Refer to Table 2-2 to
make sure you have the appropriate cable for your pin connector.

6. Connect your field signals to the BNC-2090 at the BNC connectors
or spring terminals. Refer to

Connecting Digital I/O Signals

7. Turn on the computer. If the green power LED, located on the front
panel of the BNC-2090 to the right of the spring terminal blocks,
does not light when you power on the DAQ board, turn off the
power for the BNC-2090 and make sure the power switch is in the
correct position for the board you are using.

8. When you have finished using your BNC-2090, be sure you turn off
any powered external signals to the BNC-2090
your computer.

, for more information.

Analog Input

, for more information.

, in Chapter 3,

Connecting Analog Inputs

for more detailed information.

Signal Conditioning

Signal Conditioning

or

before

you turn off

Warning:

BNC-2090 User Manual 2-6

The BNC-2090 is not designed for any input voltages greater than 42 V,
even if a user-installed voltage divider reduces the voltage to within the
input range of the DAQ board. Input voltages greater than 42 V can
damage the BNC-2090, any and all boards connected to it, and the host



National Instruments Corporation

computer. Overvoltage can also cause an electric shock hazard for the
operator. National Instruments is
from such misuse.

Accessory-to-Board Cabling

The BNC-2090 has two 68-position connectors on the front and rear
panels that you can use to connect to your DAQ board. Table 2-2 lists
cables that you can use with the BNC-2090.

Chapter 2 Configuration, Installation, and Signal Connection

liable for damage or injury resulting

NOT

Caution:

Table 2-2.

DAQ Board

100-pin MIO

BNC-2090 Cabling Options

Required Cabling

SH1006868
68-pin MIO SH6868 or R6868
50-pin MIO and PC-LPM-16* SH6850 or R6850

*When you are using the PC-LPM-16 board with the BNC-2090, some signal labels
on the BNC-2090 front panel are invalid. Refer to Table B-1 for the valid signals and
their function.

Do not connect the BNC-2090 to any board other than a National
Instruments MIO or PC-LPM-16 DAQ board, the SC-2070/72 board, or the
SC-205X cable adapter board. Doing so can damage the BNC-2090, the
DAQ board, or host computer. National Instruments is

liable for

NOT

damages resulting from these connections.

If you want to condition digital I/O port signals with the National
Instruments SC-206X Series boards, you must use the SC-205X Series
cable adapter board with your DAQ board.

If you are using an SC-205X Series cable adapter board or an SC-207X
Series general-purpose termination breadboard with the BNC-2090,
refer to your SC-205X Series and SC-207X user manuals for installation
instructions. Then connect the SC-207X Series board and the SC-205X
Series board to the BNC-2090 using the appropriate cable. Figure 2-4
shows the BNC-2090 connected directly to different DAQ systems.
Figure 2-5 shows the BNC-2090 connected to DAQ boards and
SC-20XX boards.

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National Instruments Corporation 2-7 BNC-2090 User Manual

Chapter 2 Configuration, Installation, and Signal Connection

68-Pin MIO
DAQ Board

100-Pin MIO

DAQ Board

50-Pin MIO

or PC-LPM-16

DAQ Board

68-Position

Connector

100-Position

Connector

50-Position

Connector

SH6868 or R6868 Cable

SH1006868 Cable

SH6850 or R6850 Cable

68-Position

Connector

MIO-16

68-Position

Connector

68-Position

Connector

BNC-2090

BNC-2090

68-Position

Connector

BNC-2090

BNC-2090

100-Pin MIO

DAQ Board

Figure 2-4.

SH100100 Cable

SC-2056 Cable

Adapter Board

Direct Connection of an MIO Board to the BNC-2090

BNC-2090 User Manual 2-8

SH6850 Cable

SH6850 Cable

SH6850 Cable

SH6850 Cable



National Instruments Corporation

BNC-2090

BNC-2090

BNC-2090

MIO or
PC-LPM-16
DAQ Board

BNC-2090

Chapter 2 Configuration, Installation, and Signal Connection

SC-2070/72

General-Purpose

Termination
Breadboard

SC-206

X

SC-2050

Cable Adapter

Board

Digital I/O

Series

or

8-Channel SSR

SH6868, R6868, SH6850,
R6850 or SH1006868 Cable

Figure 2-5.

Connection between the DAQ Board, the BNC-2090 and SC-20XX Boards

SH6850 or R6850 Cable

Connecting Your Signals

The BNC-2090 board has BNC connectors for all analog signals, spring
terminal blocks for digital signals, and two user-defined connectors.

All of the analog signals from the MIO board are available at the front
panel of the BNC-2090. Because these signals are not conditioned or
changed in any way by the BNC-2090, refer to your MIO board user
manual for information on the use of these signals.

Table 2-3 shows the front panel labels for the BNC and terminal block
signal connectors. Refer to your MIO board user manual for more
information on these signals.

Table 2-3.

BNC-2090 Front Panel Labels

BNC
Connectors

ACH<0..15>

26-Pin Cable

BNC-2090 Front Panel Labels

Signal Description

Analog Channels 0 through 15

DAC0OUT D/A Converter 0 Out
DAC1OUT D/A Converter 1 Out
EXTREF External Reference
PFI0/TRIG1 Programmable Function I0/Trigger 1



National Instruments Corporation 2-9 BNC-2090 User Manual

Chapter 2 Configuration, Installation, and Signal Connection

Table 2-3.

BNC-2090 Front Panel Labels

USER1

USER2 User-Defined 2

Terminal

DIO<7..0>

Blocks

DGND1 Digital Ground 1
USER1 User-Defined 1

EXSTRB* External Strobe
SCANCLK Scan Clock
+5 V +5 V Power
GND Ground

BNC-2090 Front Panel Labels (Continued)

Signal Description

User-Defined 1
(Connected to USER1 Terminal Block)

(Connected to USER2 Terminal Block)
Digital Input/Output Channels 7 through 0

(Connected to USER1 BNC)

PFI<1..9> Programmable Function Input Channels

DGND2 Digital Ground 2
USER2 User-Defined 2

FREQOUT Frequency Out
CTR1OUT Counter 1 Out
CTR0OUT Counter 0 Out

BNC-2090 User Manual 2-10

1 through 9

(Connected to USER2 BNC)



National Instruments Corporation

Connecting Analog Inputs

Connecting Nonreferenced (or Floating) Signal Sources

A floating signal source is a signal source that is not connected in any
way to the building ground system but has an isolated ground-reference
point. If an instrument or device has an isolated output, that instrument
or device falls into the floating signal source category. Some examples
of floating signal sources are: thermocouples, transformers, battery­powered devices, optical isolators, and isolation amplifiers. The ground
reference of a floating source must be tied to the ground of the DAQ
board to establish a local or onboard reference for the signal.

DIFF Inputs

To provide a return path for the instrumentation amplifier bias currents,
floating sources must have a 10–100 kΩ resistor to AIGND on one input
if DC-coupled, or both inputs if AC-coupled. For more detailed
information on connections to floating signal sources and differential
inputs, refer to the configuration chapter in your MIO-16 board user
manual.

Chapter 2 Configuration, Installation, and Signal Connection

You can install these bias resistors in positions A and B (see Table 3-1
and Figure 3-2) of the BNC-2090. Figure 2-6 shows both the schematic
and the component placement for a single 100 kΩ bias return resistor on
the negative input from a floating source connected to channel 1
(B position in Table 3-1). Refer to Chapter 3,

Application Examples,

for information on building additional signal

Signal Conditioning

conditioning circuitry, such as filters and attenuators, in the open
component positions.

+

To Input

Mux

Figure 2-6.



National Instruments Corporation 2-11 BNC-2090 User Manual

C2(E)

-

Bias Return Resistor for DC-Coupled Floating Source on

R21(C)

R4 = 100 kΩ(B)

R22(D)

Channel 1 in DIFF Mode

R3(A)

AIGND

J2

Chapter 2 Configuration, Installation, and Signal Connection

SE Inputs

When measuring floating signal sources, configure the MIO board to
supply a ground reference by placing the board in RSE mode. This
mode ties the negative input of the MIO board instrumentation
amplifier to the analog ground.

When the MIO board is configured for RSE mode, keep your
BNC-2090 in the factory-default configuration, in which the 0 Ω
jumpers are in the two series positions, C and D (see Table 3-1) and all
of the signal grounds are tied to AIGND. Refer to Chapter 3,

Conditioning Application Examples,

additional signal-conditioning circuitry, such as filters and attenuators,
in the open-component positions.

Connecting Ground-Referenced Signal Sources

A grounded signal source is connected in some way to the building
system ground; therefore, the signal source is already connected to a
common ground point with respect to the DAQ board (assuming the
host computer is plugged into the same power system). The nonisolated
outputs of instruments and devices that plug into the building power
system fall into this category.

Signal

for information on building

DIFF Inputs

If the MIO board is configured for differential inputs, ground­referenced signal sources connected to the BNC-2090 need no special
components added to the BNC-2090. You can leave the inputs of the
BNC-2090 in the factory-default configuration, with the 0 Ω jumpers in
the two series positions, C and D (see Table 3-1). Refer to Chapter 3,

Signal Conditioning Application Examples,

signal-conditioning circuitry, such as filters and attenuators, in the
open-component positions.

SE Inputs

When measuring ground-referenced signals, the external signal
supplies its own reference ground point and the MIO board should not
supply one. Therefore, configure the MIO board for the NRSE mode, in
which all of the signal grounds are tied to AISENSE, which connects to
the negative input of the instrumentation amplifier on the MIO board.
You can leave the inputs of the BNC-2090 in the factory-default
configuration, with the 0 Ω jumpers in the series position (C or D,
depending on the channel). You should not use the open positions,

BNC-2090 User Manual 2-12

for information on building



National Instruments Corporation

A and B (see Table 3-1 and Figure 3-2), that connect the input to
AIGND. This incorrect ground reference can cause inaccurate
measurements.

Connecting Analog Outputs

Each analog output BNC connector has two open-component positions
for optional signal conditioning components. One of these is designated
as a resistor and the other as a capacitor. DAC1OUT circuitry is
identical to that of DAC0OUT, but the component positions for
DAC0OUT are labeled R17 and C9 and the component positions for
DAC1OUT are labeled R18 and C10. Figure 2-7 shows the equivalent
circuit for DAC0OUT.

The board is shipped with 0 Ω jumpers inserted into the R17 and R18
positions, shown in Figure 3-8. You can easily remove these to build
passive analog output signal conditioning circuits, such as voltage
dividers and lowpass filters. Refer to Chapter 3,

Application Examples

DAC0OUT

Chapter 2 Configuration, Installation, and Signal Connection

Signal Conditioning

, for more information.

R17

Factory-Installed

0 Ω Jumper

C9

AIGND

Figure 2-7. Analog Output Schematic for DACs

J9

Connecting Digital I/O Signals

Use the BNC-2090 BNC connectors and spring terminal blocks to
connect your digital signals to your DAQ board. When connecting
signals to the spring terminal blocks, you can use up to 20 AWG wire
with the insulation stripped to 0.5 in. Table 2-3 lists labels for each
signal connector and terminal block.

Notice that there are two user-defined BNC connectors (USER1,
USER2) that are connected to the spring terminal blocks labeled
USER1 and USER2. These terminals and their associated BNC



National Instruments Corporation 2-13 BNC-2090 User Manual

Chapter 2 Configuration, Installation, and Signal Connection

connectors provide some flexibility in choosing up to two additional
digital/timing signals that you can access via BNC connectors. For
example, if an application requires access to CTR0OUT and CTR1OUT
signals, you can wire the spring terminals labeled CTR0OUT and
CTR1OUT to terminals labeled USER1 and USER2, respectively. This
configures BNC connector USER1 as CTR0OUT and USER2 as
CTR1OUT.

All of the digital signals from the MIO board are available at the front
panel of the BNC-2090. Refer to your MIO board user manual for
information on the use of these signals.

If you want optical isolation of or relay control by the digital I/O lines,
you must use the SC-2050 cable adapter board and the appropriate
SC-206X Series digital signal conditioning board. If you want access to
all MIO signals via screw terminals, you must use the SC-2070 or
SC-2072 board. For more information on the SC-205X Series boards,
the SC-206X Series boards, or the SC-207X Series boards, refer to
either your National Instruments catalog, the SC-205X Series User

Manual, the SC-206X Series User Manual, or the SC-207X Series User
Manual.

BNC-2090 User Manual 2-14



National Instruments Corporation

Signal Conditioning

Chapter

Application Examples

This chapter contains instructions for adding signal conditioning
components to your BNC-2090 and contains signal conditioning
examples for the BNC-2090 in use with MIO boards.

Adding Signal Conditioning Components

The BNC-2090 has open-component positions in the input paths into
which you can insert resistors and capacitors for conditioning the 16
single-ended or 8 differential analog input signals. You can also use the
BNC-2090 in conjunction with other signal conditioning accessories.
This chapter covers several types of signal conditioning applications
including filtering and attenuation.

To add signal conditioning components to the BNC-2090, you must
disassemble the BNC-2090 to gain access to the open-component
positions.

The figures in this section give examples using a specific channel. If
you want to install the circuit in a different channel, consult Table 3-1
to determine the equivalent component positions for the other channels.

3

Figure 3-1 shows the disassembly of the BNC-2090.



National Instruments Corporation 3-1 BNC-2090 User Manual

Chapter 3 Signal Conditioning Application Examples

5

NATIONAL

INSTR MUENTS

4

3

1

BNC-2090

2

6

7

1 Front Panel Screws
4 Front Panel Nut
7 Side Panel Screw

2 Front Connector Screws
50 Ω Jumpers

Figure 3-1.

Disassembly of the BNC-2090

1. Remove the six front panel screws.

2. Remove one side panel screw.

3. Remove two rear panel screws.

4. Hold the front panel and slide the unit out of the metal case.

5. Remove the 22 front panel nuts and washers on the BNC
connectors.

6. Remove two front connector screws.

7. Carefully slide the front panel off the unit and separate the two
printed wire boards (PWBs).

8. Install and/or remove components as necessary. Refer to

and Desoldering on the BNC-2090

9. Reassemble the BNC-2090 in reverse order. When reassembling
the two PWBs together, make sure that all the pins are aligned in
the correct holes on the board-to-board connector.

BNC-2090 User Manual 3-2

3 Front Panel Washer
6 Rear Panel Screws

for more information.



National Instruments Corporation

Soldering

Chapter 3 Signal Conditioning Application Examples

Soldering and Desoldering on the BNC-2090

Some applications require you to modify the PWB, usually by removing
0 Ω jumpers and adding components. The BNC-2090 is shipped with
0 Ω jumpers in the C and D positions (see Table 3-1 and Figure 3-2).
Use vacuum-type tools when desoldering on the BNC-2090 and avoid
damaging component pads.

Use a low-wattage soldering iron (20 to 30 W) when soldering to the
board. You should use only rosin-core, electronic-grade solder. Acid­core solder damages the printed circuit board and components.

Analog Input

Each analog input signal has several open positions for passive signal
conditioning components. Four of these positions are designated as
resistors and one is designated as a capacitor. The factory-default
positions for the 0 Ω jumpers are the C and D positions of the input
network, as shown in Figure 3-2. You can remove these 0 Ω jumpers to
build analog input signal conditioning circuits. You can also add
passive analog input signal conditioning, such as filters and dividers.

The component positions are different for each channel. Figure 3-2
shows the onboard equivalent circuit.

Table 3-1.

Channel

Differential Single-Ended A B C D E

0
1 1, 9 R3 R4 R21 R22 C2
2 2, 10 R5 R6 R23 R24 C3
3 3, 11 R7 R8 R25 R26 C4
4 4, 12 R9 R10 R27 R28 C5
5 5, 13 R11 R12 R29 R30 C6



National Instruments Corporation 3-3 BNC-2090 User Manual

0, 8 R1 R2 R19 R20 C1

Channel Component Positions

Position in Figure 3-2

Chapter 3 Signal Conditioning Application Examples

Table 3-1.

Channel

Channel Component Positions (Continued)

Position in Figure 3-2

Differential Single-Ended A B C D E

6

6, 14 R13 R14 R31 R32 C7

7 7, 15 R15 R16 R33 R34 C8

NRSE

AISENSE

AIGND

DIFF

CH 8

BNC

COMMON

SW1

R2 R1

B

SE

CH 0

BNC

AIGND

RSE
SW9

A

D

R20

Figure 3-2.

BNC-2090 User Manual 3-4

Factory-Installed

0 Ω Jumpers

C
R19

C1

E

ACH8

(-IN)

To Input Multiplexer

of MIO Board

ACH0

(+IN)

Onboard Equivalent Circuit for DIFF Mode



National Instruments Corporation

Building Lowpass Filters

You can install simple, RC lowpass filters in the BNC-2090 on any
differential input channel. The filters are useful for accurate
measurement and noise rejection. By substituting resistance and
capacitance values into the following formula (hereafter referred to as
Formula 3-1), you can calculate a simple, one-pole RC filter to have a

-3 dB point cutoff frequency (fc):

Chapter 3 Signal Conditioning Application Examples

Amplitude

0.1

0.01

0.001

0.0001

1

-------------------=

f

c

(2πRC)

The frequency response rolls off at a rate of -20 dB per decade of
increase thereafter. Figure 3-3 shows a Bode plot of the amplitude
versus normalized frequency.

1

0.1 1 10 100 1,000 10,000
(fc)

Normalized Frequency

(Formula 3-1)

dB

0

-20

-40

-60

-80

Figure 3-3.

Normalized Frequency Response of Lowpass Filter

When measuring low-frequency signals (about 4 Hz), if you have
400 Hz noise on your input signals, you can add a lowpass filter with a
cutoff frequency of 4 Hz. The 400 Hz noise then attenuates by 40 dB.
Notice that your 4 Hz signal also attenuates, but by only 3 dB. Do not
neglect any potential attenuation of signals of interest by this low-order
filter.

You must also choose the filter component values. You can select the
resistance or the capacitance arbitrarily; one value determines the other.



National Instruments Corporation 3-5 BNC-2090 User Manual

Chapter 3 Signal Conditioning Application Examples

Picking the capacitor first and letting its value determine the resistance
required is preferable because more standard resistor values are
available. If a capacitance of 1 µF is available, the resistance is (by
substitution into Formula 3-1) about 39.8 kΩ. This resistance must be
divided by two to get the resistor value on each input of a differential
channel. Therefore, in this example, each input channel has a 19.89 kΩ
resistor (or the closest standard value) in its series positions, C and D.
The closest standard 5% tolerance resistors are 20 kΩ. The closest
standard 0.5% resistors are 19.8 kΩ. National Instruments recommends
using 1% or better tolerance resistors in this application because
differences between the resistor values degrade the common-mode
rejection ratio (CMRR). Figure 3-4 shows both the schematic and the
component placement for a 4 Hz lowpass filter placed on differential
input channel 1. If the input signal source is floating, you must place a
bias return resistor in the B position (R4 in this case).

Note:

The BNC-2090 open-component locations do not facilitate RC lowpass
filters with the MIO board configured for single-ended inputs. Therefore,
if you configure the MIO board for single-ended inputs, you must build
lowpass filters external to the BNC-2090.

Building Highpass Filters

You can install simple, RC highpass filters in the BNC-2090 on any
differential input channel. The filters are useful for accurate high­frequency measurement and low-frequency noise rejection. By
substituting resistance and capacitance values into Formula 3-1, you
can calculate a simple, one-pole RC filter to have a -3 dB point fc. The
frequency response rolls off at a rate of -20 dB per decade decrease

To Input

Mux

+

-

Figure 3-4.

R21 = 19.8 kΩ(C)

C2 = 1 µF(E)

R22 = 19.8 kΩ(D)

Lowpass Filter on Differential Channel 1

J2

BNC-2090 User Manual 3-6



National Instruments Corporation

Chapter 3 Signal Conditioning Application Examples

thereafter. Figure 3-5 shows a Bode plot of the amplitude versus
normalized frequency.

Amplitude

0.1

0.01

0.001

0.0001

1

0.0001 0.001 0.01 0.1 1 10

Normalized Frequency

Figure 3-5.

Normalized Frequency Response of Highpass Filter

(fc)

When measuring high-frequency signals (about 50 kHz), if you have
50 Hz noise on your input signals, you can add a highpass filter with a
cutoff frequency of 50 kHz. The 50 Hz noise then attenuates by 60 dB.
Notice that your 50 kHz signal also attenuates, but by only 3 dB. Do
not neglect any potential attenuation of signals of interest if you add a
low-order filter.

dB

0

-20

-40

-60

-80

You must also choose the filter component values. You can select the
resistance or the capacitance arbitrarily; one value determines the other.
Picking the capacitor first and letting its value determine the resistance
required is preferable because more standard resistor values are
available. The filter circuit has one series capacitor on each input signal
of the differential channel. Because the two capacitors are in series, the
capacitance value that must be substituted into Formula 3-1 is the series
capacitance of the two capacitors. For two capacitors in series, the net
capacitance is the reciprocal of the sum of the reciprocals of the two
capacitances. For example, two 0.001 µF capacitors in series have a net
capacitance of 0.0005 µF. The two capacitors should be the same value,
or the CMRR is degraded. If capacitors of 0.001 µF are available, the
resistance is (by substitution into Formula 3-1) about 6.4 kΩ.
Therefore, in this example, the input channel has a 6.34 kΩ resistor (or



National Instruments Corporation 3-7 BNC-2090 User Manual

Chapter 3 Signal Conditioning Application Examples

the closest standard value) in its capacitor position, E. The closest
standard 5% tolerance resistors are 6.2 kΩ. The closest standard 1%
resistors are 6.34 kΩ. Figure 3-6 shows both the schematic and the
component placement for a 50 kHz highpass filter placed on differential
input channel 1. If the input signal source is floating, you must place a
bias return resistor in the B position (R4 in this case).

Note:

Highpass filters generally exhibit poorer common-mode rejection
characteristics than lowpass filters because capacitors are in the series
input paths. Capacitors have poorer tolerances than resistors, and
matching the input impedances is crucial for good common-mode
rejection.

The BNC-2090 open component locations do not facilitate RC highpass
filters with the MIO board configured for single-ended inputs. Therefore,
if the MIO board is configured for single-ended inputs, you must build
highpass filters external to the BNC-2090.

+

R21 = .001 µf(C)

To Input

Mux

-

Figure 3-6.

C2 = 6.34 kΩ(E)

R22 = .001 µf(D)

Highpass Filter on Differential Channel 1

J2

Building Attenuators (Voltage Dividers)

Attenuators or voltage dividers allow voltage measurements larger than
the maximum input range of MIO boards. For example, voltage signals
in the ±20 V range can be measured by building a 2:1 voltage divider
circuit.

You can connect attenuators to the analog inputs of the BNC-2090
when the inputs from its DAQ board are in DIFF mode. The BNC-2090
open component positions do not facilitate voltage dividers with the
MIO board configured for single-ended input signals. Therefore, if you
configure the MIO board for single-ended inputs, you must build

BNC-2090 User Manual 3-8



National Instruments Corporation

Chapter 3 Signal Conditioning Application Examples

attenuators external to the BNC-2090. You can use attenuators to
reduce a signal that is outside the normal input range of the DAQ board
(±10 V maximum).

Warning:

The BNC-2090 is not designed for any input voltages greater than 42 V,
even if a user-installed voltage divider reduces the voltage to within the
input range of the DAQ board. Input voltages greater than 42 V can
damage the BNC-2090, any and all boards connected to it, and the host
computer. Overvoltage can also cause an electric shock hazard for the
operator. National Instruments is

liable for damage or injury

NOT

resulting from such misuse.

Figure 3-7 shows a three-resistor circuit for attenuating voltages at the
differential inputs of the BNC-2090. The figure also shows the
placement of the resistors on the open-component positions for
differential channel 1. The gain (G) of this attenuator is given by the
following formula:

R

-----------------------------------------=

G

Therefore, the input to the MIO board (V

V

MIO

E

RCRDR

++()

VSCG()=

E

) is as follows:

MIO

(Formula 3-2)

(Formula 3-3)

where VSC is the voltage applied to the BNC connectors of the
BNC-2090. The accuracy of this gain equation depends on the
tolerances of the resistors used.

+

R21 = 10 kΩ(C)

To Input

Mux

-

Figure 3-7.

C2 = 10 kΩ(E)

R22 = 10 kΩ(D)

Attenuator for Use with Differential Inputs

J2

Using the values in Figure 3-7,



National Instruments Corporation 3-9 BNC-2090 User Manual

Chapter 3 Signal Conditioning Application Examples

G

----------------------------------------------------------------- -

10 kΩ 10 kΩ 10 kΩ++()

10 kΩ

1

-- -==
3

(Formula 3-4)

Therefore,

1

-- -

V

V

MIO

()=

SC

3

(Formula 3-5)

When the MIO board is configured for ±10 V input signals, the board
can acquire ±30 V signals with this attenuator circuit.

Notice that the input impedance for the channels employing voltage
dividers circuit is reduced. In the example above, the input impedance
has been reduced to:

10 kΩ + 10 kΩ + 10 kΩ = 30 k

Ω

The reduced input impedance can cause loading errors for signal
sources with large source impedance. In general, the input impedance
presented by the voltage divider circuit must be much larger than the
source impedance of the signal source to avoid signal loading errors.

If your application requires the use of thermocouples, using a National
Instruments SC-2070 board is better suited for the task. The SC-2070
board is equipped with an onboard temperature sensor for use with
thermocouple cold-junction compensation.

Analog Output

Each analog output has two open-component positions for passive
signal conditioning components. One is designated as a resistor and one
is designated as a capacitor. Factory-default positions for the 0 Ω
jumpers are R17 and R18 as shown in Figure 3-8.

BNC-2090 User Manual 3-10



National Instruments Corporation

DAC1OUT

Chapter 3 Signal Conditioning Application Examples

R18

DAC1OUT

BNC Connector

DAC0OUT

BNC Connector

AGND

DAC0OUT

AGND

R17

Figure 3-8.

C10

C9

DAC0OUT and DAC1OUT

You can remove and/or install components in these locations to build
highpass and lowpass filters. Refer to

Components

for instructions.

Adding Signal Conditioning

Building Lowpass Filters

Building lowpass filters for the analog output signals is the same as for
the analog inputs. Refer to Analog Input for more detailed information
about lowpass filters and how to calculate values for lowpass filters.
Refer to Figure 3-1 for component locations. Figure 3-9 shows a 4 Hz
lowpass filter for DAC0OUT.



National Instruments Corporation 3-11 BNC-2090 User Manual

Chapter 3 Signal Conditioning Application Examples

DAC0OUT

R17 = 39.8 kΩ

AGND

Building Highpass Filters

Building highpass filters for analog output is the same as for analog
input. Refer to Analog Input for more detailed information about
highpass filters and how to calculate values for them. Refer to
Figure 3-1 for component locations. Figure 3-10 shows a 50 kHz
highpass filter for DAC0OUT.

DAC0OUT

C9 = 1 µf

Figure 3-9. Lowpass Filter on DAC0OUT

R17 = .0005 µf

C9 = 6.34 kΩ

DAC0OUT

BNC Connector

DAC0OUT

BNC Connector

AGND

Figure 3-10. Highpass Filter on DAC0OUT

BNC-2090 User Manual 3-12



National Instruments Corporation

Appendix

Specifications

This appendix lists the specifications of the BNC-2090.

Analog Input

Input Characteristics

Number of channels .......................... 16 single-ended or 8 differential

Field connection................................ 22 BNC connectors (18 analog,

Signal conditioning capability........... 5 open component positions per

Power Requirement (from host computer)

+5 VDC (±5%)

Typical........................................10 mA (no signal conditioning

Maximum....................................1 A (fuse-limited by host DAQ

A

1

2 digital, and 2 user-defined),
28 spring terminal blocks

channel that allow simple
passive; lowpass or highpass
filter; voltage attenuator circuits
in signal path

installed)

board)

Physical

Dimensions ....................................... 43.2 x 18.8 x 4.4 cm

(19 by 7.4 by 1.7 in.)

I/O connector .................................... Two 68-position male

connectors

BNC connectors ................................ 22

Spring terminal blocks ...................... 28

1. The DAC0OUT and DAC1OUT BNC connectors are for use only with MIO boards. These
connectors are connected to ±12 VDC when the PC-LPM-16 is in use.



National Instruments Corporation A-1 BNC-2090 User Manual

Appendix A Specifications

Environment

Operating temperature........................0° to 70° C

Storage temperature...........................-55° to 125° C

Relative humidity............................... 5% to 90% noncondensing

BNC-2090 User Manual A-2



National Instruments Corporation

Appendix

Using the PC-LPM-16

This appendix contains information on using the PC-LPM-16 with the

BNC-2090.

When using the PC-LPM-16 with the BNC-2090, the functions of the
front panel switches and connectors are different because of the
difference between the MIO I/O connector signals and the PC-LPM-16
I/O connector signals.

Analog I/O

The analog input section of a PC-LPM-16 DAQ board consists of

16 ground-referenced single-ended channels. Therefore, the only valid

configuration for the BNC-2090 is also RSE mode, which uses all

16 analog input BNC connectors. Switches S1 through S8 must be in

the SE position and S9 should be in the RSE position, as shown in

Figure B-1.

ACH0

ACH1

SE

SE

DIFF

ACH9

ACH8

— switch in SE or RSE mode

B

ACH2

ACH3

SE

SE SE

DIFFDIFF

DIFF

ACH10

DIFF

ACH11

ACH4

ACH12

ACH5

ACH6

ACH7

DAC0OUT

R
S

ACH15

E

N
R
S
E

DAC1OUT

SE

SE SE

DIFF

DIFF DIFF

ACH13

ACH14

Note:

Figure B-1.

All the switches are required to be in the same position; that is, S1 through

Switch Configurations for RSE Mode (PC-LPM-16)

S8 must all be in the SE position and S9 must be in the RSE position to use
the BNC-2090 with the PC-LPM-16.

DAC0OUT and DAC1OUT BNC connectors are for use with the MIO

boards only. These connectors are connected to ±12 V when the

PC-LPM-16 is in use.



National Instruments Corporation B-1 BNC-2090 User Manual

Appendix B Using the PC-LPM-16

Digital I/O

Table B-1 shows the BNC-2090 front panel labels and the
corresponding signal names when you use the accessory with a
PC-LPM-16.

Table B-1.

BNC-2090 Front Panel Labels and Corresponding Signal Names

BNC-2090 Front Panel Labels

Switches

RSE/NRSE
SE/DIFF SE

BNC

ACH<0..15>

Connectors

DAC0OUT Center is -12 V, outer is DIN1
DAC1OUT Center is +12 V, outer is DIN1
EXTREF DIN0
PFI0/TRIG1 OUT1*
USER1 Center is no change, outer DIN2

USER2 Center is no change, outer DIN2

Terminal

DIO7

Blocks

for PC-LPM-16

Signal Name for PC-LPM-16

RSE

No change

shorted to DOUT3

shorted to DOUT3
DOUT2

DIO6 DOUT0
DIO5 DIN6
DIO4 DIN4
DIO3 DOUT1
DIO2 DIN7

BNC-2090 User Manual B-2

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National Instruments Corporation

Appendix B Using the PC-LPM-16

Table B-1.

BNC-2090 Front Panel Labels and Corresponding Signal Names

for PC-LPM-16 (Continued)

BNC-2090 Front Panel Labels

DIO1
DIO0 DIN3
DGND1 DOUT3 shorted to DIN2
USER1 No change
EXSTRB* DOUT7
SCANCLK DOUT6
+5 V No change
GND No change
PFI1 EXTINT*
PFI2 EXTCONV*
PFI3 OUT0

Signal Name for PC-LPM-16

DIN5

PFI4 GATE0
PFI5 GATE1
PFI6 CLK1
PFI7 OUT2
PFI8 GATE2
PFI9 CLK2
DGND2 DOUT3 shorted to DIN2
USER2 No change
FREQOUT DGND



National Instruments Corporation B-3 BNC-2090 User Manual

Appendix B Using the PC-LPM-16

Table B-1.

BNC-2090 Front Panel Labels and Corresponding Signal Names

for PC-LPM-16 (Continued)

BNC-2090 Front Panel Labels

CTR1OUT
CTR0OUT +5 V

Signal Name for PC-LPM-16

OUT1

BNC-2090 User Manual B-4



National Instruments Corporation

Appendix

C

Customer Communication

For your convenience, this appendix contains forms to help you gather the information necessary
to help us solve your technical problems and a form you can use to comment on the product
documentation. When you contact us, we need the information on the Technical Support Form
and the configuration form, if your manual contains one, about your system configuration to
answer your questions as quickly as possible.

National Instruments has technical assistance through electronic, fax, and telephone systems to
quickly provide the information you need. Our electronic services include a bulletin board
service, an FTP site, a FaxBack system, and e-mail support. If you have a hardware or software
problem, first try the electronic support systems. If the information available on these systems
does not answer your questions, we offer fax and telephone support through our technical support
centers, which are staffed by applications engineers.

Electronic Services

Bulletin Board Support

National Instruments has BBS and FTP sites dedicated for 24-hour support with a collection of
files and documents to answer most common customer questions. From these sites, you can also
download the latest instrument drivers, updates, and example programs. For recorded instructions
on how to use the bulletin board and FTP services and for BBS automated information, call (512)
795-6990. You can access these services at:

United States: [phone] or [phone]

Up to 14,400 baud, 8 data bits, 1 stop bit, no parity

United Kingdom: 01635 551422

Up to 9,600 baud, 8 data bits, 1 stop bit, no parity

France: 1 48 65 15 59

Up to 9,600 baud, 8 data bits, 1 stop bit, no parity

FTP Support

To access our FTP site, log on to our Internet host,
your Internet address, such as
and documents are located in the



National Instruments Corporation C-1 BNC-2090 User Manual

[e-mail]

/support

ftp.natinst.com

directories.

, as anonymous and use

, as your password. The support files

FaxBack Support

FaxBack is a 24-hour information retrieval system containing a library of documents on a wide
range of technical information. You can access FaxBack from a touch-tone telephone at the
following number:

[phone]

E-Mail Support (currently U.S. only)

You can submit technical support questions to the appropriate applications engineering team
through e-mail at the Internet addresses listed below. Remember to include your name, address,
and phone number so we can contact you with solutions and suggestions.

GPIB:
DAQ:
VXI:
LabWindows:

[e-mail]

[e-mail]

[e-mail]

[e-mail]

LabVIEW:
HiQ:
VISA:

[e-mail]

[e-mail]

[e-mail]

Fax and Telephone Support

National Instruments has branch offices all over the world. Use the list below to find the technical
support number for your country. If there is no National Instruments office in your country,
contact the source from which you purchased your software to obtain support.

Telephone Fax

Australia 03 9 879 9422 03 9 879 9179
Austria 0662 45 79 90 0 0662 45 79 90 19
Belgium 02 757 00 20 02 757 03 11
Canada (Ontario) 519 622 9310
Canada (Quebec) 514 694 8521 514 694 4399
Denmark 45 76 26 00 45 76 26 02
Finland 90 527 2321 90 502 2930
France 1 48 14 24 24 1 48 14 24 14
Germany 089 741 31 30 089 714 60 35
Hong Kong 2645 3186 2686 8505
Italy 02 413091 02 41309215
Japan 03 5472 2970 03 5472 2977
Korea 02 596 7456 02 596 7455
Mexico 95 800 010 0793 5 520 3282
Netherlands 0348 433466 0348 430673
Norway 32 84 84 00 32 84 86 00
Singapore 2265886 2265887
Spain 91 640 0085 91 640 0533
Sweden 08 730 49 70 08 730 43 70
Switzerland 056 200 51 51 056 200 51 55
Taiwan 02 377 1200 02 737 4644
U.K. 01635 523545 01635 523154

Technical Support Form

Photocopy this form and update it each time you make changes to your software or hardware, and
use the completed copy of this form as a reference for your current configuration. Completing
this form accurately before contacting National Instruments for technical support helps our
applications engineers answer your questions more efficiently.

If you are using any National Instruments hardware or software products related to this problem,
include the configuration forms from their user manuals. Include additional pages if necessary.

Name__________________________________________________________________________
Company_______________________________________________________________________
Address ________________________________________________________________________
_______________________________________________________________________________
Fax (___ )___________________ Phone (___ ) ______________________________________
Computer brand ________________ Model ________________ Processor __________________
Operating system (include version number)____________________________________________
Clock speed ______MHz RAM _____MB Display adapter _________________________
Mouse ___yes ___no Other adapters installed _______________________________________
Hard disk capacity _____MB Brand ___________________________________________
Instruments used ________________________________________________________________
_______________________________________________________________________________
National Instruments hardware product model___________ Revision________________________
Configuration ___________________________________________________________________
National Instruments software product____________________________ Version ____________
Configuration ___________________________________________________________________
The problem is: _________________________________________________________________
_______________________________________________________________________________
_______________________________________________________________________________
_______________________________________________________________________________
_______________________________________________________________________________
List any error messages: ___________________________________________________________
_______________________________________________________________________________
_______________________________________________________________________________
The following steps reproduce the problem: ___________________________________________
_______________________________________________________________________________
_______________________________________________________________________________
_______________________________________________________________________________
_______________________________________________________________________________
_______________________________________________________________________________

BNC-2090 Hardware Configuration Form

Record the settings and revisions of your hardware on the line to the right of each item. Complete
a new copy of this form each time you revise your hardware configuration, and use this form as a
reference for your current configuration. Completing this form accurately before contacting
National Instruments for technical support helps our applications engineers answer your questions
more efficiently.

National Instruments Products

DAQ hardware _______________________________________________________________
SW1 _______________________________________________________________________
SW2 _______________________________________________________________________
SW3 _______________________________________________________________________
SW4 ________________________________________________________________________
SW5 _______________________________________________________________________
SW6 _______________________________________________________________________
SW7 _______________________________________________________________________
SW8 _______________________________________________________________________
SW9 _______________________________________________________________________
Jumper W1 __________________________________________________________________
Power selection switch _________________________________________________________

Documentation Comment Form

National Instruments encourages you to comment on the documentation supplied with our
products. This information helps us provide quality products to meet your needs.

Title:
Edition Date:
Part Number:

Please comment on the completeness, clarity, and organization of the manual.
_______________________________________________________________________________
_______________________________________________________________________________
_______________________________________________________________________________
_______________________________________________________________________________
_______________________________________________________________________________
_______________________________________________________________________________
_______________________________________________________________________________

If you find errors in the manual, please record the page numbers and describe the errors.
_______________________________________________________________________________
_______________________________________________________________________________
_______________________________________________________________________________
_______________________________________________________________________________
_______________________________________________________________________________
_______________________________________________________________________________
_______________________________________________________________________________

BNC-2090 User Manual

March 1996
321183A-01

Thank you for your help.
Name _________________________________________________________________________
Title __________________________________________________________________________
Company_______________________________________________________________________
Address _______________________________________________________________________
_______________________________________________________________________________
Phone ( )_____________________________________________________________________

Mail to:

Technical Publications
National Instruments Corporation National Instruments Corporation
6504 Bridge Point Parkway [phone]
Austin, TX 78730-5039

Fax to:

Technical Publications

Prefix Meaning Value

Glossary

m- milli- 10

µ

- micro- 10

n- nano- 10

°
Ω

degrees
ohms

-3

-6

-9

% percent
+5 V +5 volt signal
A amperes
AC alternating current
ACH analog channel
A/D analog to digital
AIGND analog input ground
AISENSE analog input sense signal
ANSI American National Standards Institute
C Celsius
CMRR common-mode rejection ratio
COMMON common signal
CTROUT counter output signal



National Instruments Corporation G-1 BNC-2090 User Manual

Glossary

D/A digital to analog
DAC0OUT DAC 0 output signal
dB decibels
DC direct current
DGND digital ground
DIFF differential input
DIO digital I/O
EXTREF external reference signal
EXTSTRB external strobe signal
F farads
FREQOUT frequency out signal
G gain
GND ground signal
Hz hertz
in. inches
I/O input/output
LED light-emitting diode
m meters
MIO multifunction I/O
NRSE nonreferenced single-ended input
PFI programmable function input
RC resistance-capacitance
RSE referenced single-ended input
SC signal conditioning

BNC-2090 User Manual G-2

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National Instruments Corporation

SCANCLK scan clock signal
SE single-ended input
SW switch
TRIG trigger signal
USER user-defined signal
V volts
VDC volts, direct current
W watts

Glossary



National Instruments Corporation G-3 BNC-2090 User Manual

Index

A

analog inputs, 2-11

ground-referenced signal sources, 2-12

DIFF inputs, 2-12
SE inputs, 2-12

nonreferenced (or floating) signal

sources, 2-11

DIFF inputs, 2-11

bias return resistor for

DC-coupled floating source on
channel 1 (figure), 2-11

SE inputs, 2-12

analog outputs, 2-13

schematic for DACs (figure), 2-13

B

BNC-2090, 1-1

figure, 2-1

BNC connectors (table), 2-9

C

cable adapter boards, 2-7

connected to MIO (figure), 2-8
connected to BNC-2090 (figure), 2-9

cabling

options (table), 2-7
MIO board connection (figure), 2-8
SC-20XX board connection (figure), 2-9

configuring your BNC-2090, 2-1

mode configuration, 2-2

DIFF input mode, 2-2
RSE and NRSE input mode, 2-2

power selection switch, 2-3

shield ground jumper, 2-3

accessing jumper 1 (figure), 2-5
settings (table), 2-4

signal conditioning jumpers, 2-5

connecting your signals, 2-9

analog inputs, 2-11

ground-referenced signal

sources, 2-12

DIFF inputs, 2-12
SE inputs, 2-12

nonreferenced (or floating) signal

sources, 2-11

DIFF inputs, 2-11

SE inputs, 2-12
connector labels (table), 2-9
analog outputs, 2-13

schematic for DACs (figure), 2-12
conventions,
customer communication, C-1

x

D

DACs schematic (figure), 2-13
desoldering on the BNC-2090, 3-3
DIFF input

BNC-2090 mode configuration, 2-2
ground-referenced signal sources, 2-12
nonreferenced signal sources, 2-11

bias return resistor for DC-coupled

floating source on channel 1

(figure), 2-11
digital I/O signal connection, 2-13
disassembly of the BNC-2090 (figure), 3-2



National Instruments Corporation I -1 BNC-2090 User Manual

Index

F

filters.

fuse and power LED, A-1

See also

filters.

analog input, 3-6

building attenuators (voltage

dividers), 3-8

building highpass, 3-6

DIFF channel 1 (figure), 3-8
normalized frequency response

(figure), 3-7

building lowpass filters, 3-5

DIFF channel 1 (figure), 3-6
normalized frequency response

(figure), 3-5

analog output, 3-10

building lowpass filters, 3-11

DAC0OUT (figure), 3-12

building highpass filters, 3-12

DAC0OUT (figure), 3-12

highpass filters, lowpass

G

general-purpose termination

breadboards, 2-7

connected to MIO (figure), 2-8
connected to BNC-2090 (figure), 2-9

ground jumper, 2-3

setting options (table), 2-4

ground-referenced signal sources, 2-12

DIFF inputs, 2-12
SE inputs, 2-12

H

highpass filters

analog input, 3-6

building filters, 3-6

DIFF channel 1 (figure), 3-8
normalized frequency response

(figure), 3-7

analog output, 3-10

building filters, 3-12

DAC0OUT (figure), 3-12

I

installation, 2-6

accessory-to-board cabling, 2-7

cabling options (table), 2-7

MIO board connection (figure), 2-8
SC-20XX board connection (figure), 2-9

J

jumper, W1 shield ground, 2-3

setting options (table), 2-4

L

lowpass filters

analog input, 3-6

building filters, 3-5

DIFF channel 1 (figure), 3-6
normalized frequency response

(figure), 3-5

analog output,3-10

building filters, 3-11

DAC0OUT (figure), 3-12

M

MIO board, 2-1

analog input, 3-3
analog output, 3-10

mode configuration, 2-2

DIFF input mode, 2-2
RSE and NRSE input mode, 2-2

N

nonreferenced (or floating) signal

sources, 2-11

DIFF inputs, 2-11

bias return resistor for DC-coupled

floating source on channel 1
(figure), 2-11

SE inputs, 2-12

BNC-2090 User Manual I -2

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National Instruments Corporation

Index

NRSE input mode configuration, 2-2

O

operating environment, A-2
optional equipment, 1-2

P

parts location (figure), 2-1
PC-LPM-16, using with the BNC-2090, B-1

analog I/O, B-1
BNC-2090 switch configurations

(figure), B-1

digital I/O, B-2

signal names and BNC-2090

connector labels (table), B-2
physical specifications, A-1
power requirements, A-1
power selection switch, 2-3

R

rack mounting, 2-6
related documentation,
RSE input mode configuration, 2-2

x

S

SC-20XX boards, 1-2, 2-7

connected to MIO (figure), 2-8

connected to BNC-2090 (figure), 2-9
schematic for DACs (figure), 2-13
SE input

BNC-2090 mode configurations, 2-2

ground-referenced signal sources, 2-12

nonreferenced (or floating) signal

sources, 2-12

shield ground jumper, 2-3

settings (table), 2-4

accessing jumper on BNC-2090

(figure), 2-5

signal conditioning components, 2-5

adding to the BNC-2090, 3-1

disassembly of the BNC-2090, 3-2

soldering and desoldering on

the BNC-2090, 3-3

signal conditioning examples, 3-3

analog input, 3-3

building attenuators, 3-8

DIFF inputs (figure), 3-9

building highpass filters, 3-6

DIFF channel 1 (figure), 3-8
normalized frequency response

(figure), 3-7

building lowpass filters, 3-5

DIFF channel 1 (figure), 3-6
normalized frequency response

(figure), 3-5

channel component positions

(table), 3-3

onboard equivalent circuit for DIFF

mode (figure), 3-4

analog output, 3-10

DAC0OUT and DAC1OUT

(figure), 3-11

building lowpass filters, 3-11

DAC0OUT (figure), 3-12

building highpass filters, 3-12

DAC0OUT (figure), 3-12

signal connections, 2-9

connector labels (table), 2-9
analog inputs, 2-11

ground-referenced signal

sources, 2-12

DIFF inputs, 2-12
SE inputs, 2-12

nonreferenced (or floating) signal

sources, 2-11

DIFF inputs, 2-11
SE inputs, 2-12

analog outputs, 2-13

signal sources

floating, 2-11
ground-referenced, 2-12
nonreferenced, 2-11

soldering and desoldering on the

BNC-2090, 3-3



National Instruments Corporation I -3 BNC-2090 User Manual

Index

specifications, A-1
spring terminal block labels (table), 2-10
storage environment, A-2
switch configurations, 2-2 to 2-3

figure, 2-3
mode configuration, 2-2

DIFF input mode, 2-2
RSE and NRSE input mode, 2-2

T

terminal block labels (table), 2-10

V

voltage dividers, building, 3-8

DIFF inputs (figure), 3-9

W

W1 shield ground jumper, 2-3

setting options (table), 2-4

what you need to get started, 1-1

BNC-2090 User Manual I -4



National Instruments Corporation