National Instruments BNC-2140 User Manual

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BNC-2140 User Manual

Dynamic Signal Acquisition Signal Conditioning Accessory

BNC-2140 User Manual

June 1998 Edition

Part Number 321933B-01

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National Instruments Corporate Headquarters

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Important Information

Warranty

The BNC-2140 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 defect ive du ring t he wa rranty period . Th is warranty incl udes parts a nd l abor.

A Return Material Authorization (RMA) number must b e ob tain ed fro m th e facto ry an d clearl y mark ed on t he outsi de of the package before any equipment wil l be accepted for warranty work. National Instruments will pay the shippi ng costs of returning to the owner parts which are covered by warran ty.

National Instruments believes that the information in this manual is accurate. The document has been c arefully 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 th is do cume nt with ou t p rio r no ti ce to hold ers o f thi s ed itio n. The read er sh ou ld 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 docume nt o r th e in form ati on con tai ned in i t.

XCEPT AS SPECIFIED HEREIN

ANY WARRANTY OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE BY FAULT OR NEGLIGENCE ON THE PART OF NATIONAL INSTRUMENTS SHALL BE LIMITED TO THE AMOUNT THERETOFORE PAID BY THE CUSTOMER OR INCIDENTAL OR CONSEQUENTIAL DAMAGES, EVEN IF ADVISED OF THE POSSIBILITY THEREOF

National Instruments will apply regardless of the form of action, wh ether in con tract or tort , incl udin g n egli gen ce. 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, malfuncti ons, or s ervice failur es caused by own er’s fai lure to fol low 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.

ATIONAL INSTRUMENTS WILL NOT BE LIABLE FOR DAMAGES RESULTING FROM LOSS OF DATA, PROFITS, USE OF PRODUCTS

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ATIONAL INSTRUMENTS MAKES NO WARRANTIES, EXPRESS OR IMPLIED, AND SPECIFICALLY DISCLAIMS

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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.

USTOMER’S RIGHT TO RECOVER DAMAGES CAUSED

. C

. This limitation of the liability of

Trademarks

ICP® is a registered trademark of PCB Piezotronics, Inc. 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 com ponent s and tes ting inten ded to ensure a l evel of reliab ilit y suitable for use in treatment and diagnosis of humans. Applications of National Instruments products invol ving m edical 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 Instrum ents product s 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.........................................................................................vii

Conventions Used in This Manual.................................................................................viii

Related Documentation........................................... .......................................................viii

Customer Communication.............................................................................................viii

Chapter 1 Introduction

What You Need to Get Started...................................................................................... 1-2

Unpacking......................................................................................................................1-2

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

Custom Cabling .............................................................................................................1-3

Chapter 2 Installation and Configuration

Installation .....................................................................................................................2-1

Device Configuration...................................................... ...............................................2-1

Chapter 3 Signal Connections

I/O Connectors...............................................................................................................3-1

Analog Input Signal Connections..................................................................................3-5

Analog Output Signal Connections ...............................................................................3-5

Chapter 4 Theory of Operation

Functional Overview......................................................................................................4-2

Analog Input Circuitry...................................................................................................4-3

Analog Output................................................................................................................4-4

Appendix A Specifications

Analog Input....................................................................................................A-1

Voltage Input.....................................................................................A-1

Current Excitation........................................................ .....................A-1

Analog Output.................................................................................................A-2

National Instruments Corporation v BNC-2140 User Manual

Contents

Power Requirement (from DSA board)..........................................................A-2

Physical...........................................................................................................A-2

Environment....................................................................................................A-2

Appendix B Customer Communication

Glossary

Index

Figures

Figure 2-1. Switch Settings and Signal Connections...............................................2-2

Figure 3-1. BNC-2140 External 68-Pin Analog Connector ....................................3-3

Figure 4-1. BNC-2140 Block Diagram ...................................................................4-2

Tables

Table 3-1. BNC Analog I/O Connector Signal Descriptions ................................3-1

Table 3-2. 68-Pin Analog I/O Connector Signal Descriptions .............................. 3-4

BNC-2140 User Manual vi

National Instruments Corporation

About This Manual

This manual describes the electrical and mechanical aspects of the BNC-2140 accessory and contains information concerning its operation.

Organization of This Manual

The BNC-2140 User Manual is organized as follows:

• Chapter 1, Introduction, describes the BNC-2140 accessory, lists what you need to get started, explains how to unpack your BNC-2140, and describes optional equipment.

• Chapter 2, Installation and Configuration, explains how to install and configure your BNC-2140 accessory.

• Chapter 3, Signal Connections, describes how to make input and output signal connections to your BNC-2140.

• Chapter 4, Theory of Operation, contains a functional overview of the BNC-2140.

• Appendix A, Specifications, lists the specifications of the BNC-2140.

• Appendix B, Customer Communication, contains forms you can use to request help from National Instruments or to comment on our products and manuals.

• The Glossary contains an alphabetical list and description of terms used in this manual, including abbreviations, acronyms, metric prefixes, mnemonics, and symbols.

• The Index contains an alphabetical list of key terms and topics in this manual, including the page where you can find each one.

National Instruments Corporation vii BNC-2140 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, DIO<3..0>.

This icon to the left of bold italicized text denotes a note, which alerts you to important information.

bold italic Bold italic text denotes a note or caution.

italic Italic text denotes a variable, emphasis, a cross reference, or an introduction

SE SE means referenced single ended (RSE).

This icon to the left of bold italicized text denotes a caution, which advises you of precautions to take to avoid injury, data loss, or a system crash.

to a key concept.

Customer Communication

National Instruments wants to receive your comments on our products and manuals. We are interested in the applications you develop with our products, and we want to help if you have problems with them. To make it easy for you to contact us, this manual contains comment and configuration forms for you to complete. These forms are in Appendix B, Customer

Communication, at the end of this manual.

BNC-2140 User Manual viii

National Instruments Corporation

Introduction

This chapter describes the BNC-2140 accessory, lists what you need to get started, explains how to unpack your BNC-2140, and describes optional equipment.

Thank you for buying the BNC-2140 accessory for DSA.The BNC-2140 is a signal conditioning accessory specifically designed for use with a dynamic signal acquisition (DSA) series device. It interfaces four BNC signal inputs and two BNC signal outputs directly to National Instruments DSA products including the PCI-4451, PCI-4452, NI 4551, and NI 4552. The BNC-2140 connects to Integrated Circuit Piezoelectric (ICP accelerometers and microphone preamplifiers as well as any other voltage source whose output is less than ±42.4 V.

Each input channel consists of an independent 4 mA current source suitable for use with ICP type accelerometers and microphone preamplifiers. You can manually enable or disable the ICP signal conditioning on a per channel basis. When disabled, the BNC-2140 acts as a direct voltage input. You can manually switch each input channel and each output channel from differential (DIFF) to single-ended (SE) mode. In SE mode, the BNC shell tethers to a clean analog ground through a 50 Ω resistor.

)

The BNC-2140 receives power for the ICP signal conditioning from the DSA plug-in board via the 68-pin high-density connector. A green LED indicates when the ICP circuitry is powered on. When you do not require ICP signal conditioning, you can manually turn off the power to the circuits.

National Instruments Corporation 1-1 BNC-2140 User Manual

Chapter 1 Introduction

What You Need to Get Started

To set up and use your BNC-2140 device, you will need the following:

❑ BNC-2140 ❑ One of the following DSA devices:

PCI-4451 PCI-4452 NI 4551 NI 4552

❑ BNC-2140 User Manual ❑ Your computer ❑ SHC68-C68-A1 analog cable

Unpacking

Your BNC-2140 is shipped in an antistatic plastic package to prevent electrostatic damage to the device. Several components on the device can be damaged by electrostatic discharge. To avoid such damage in handling the device, take the following precautions:

• Ground yourself via a grounding strap or by holding a grounded object.

• Touch the plastic package to a metal part of your computer chassis before removing the device from the package.

• Remove the device from the package and inspect the device for loose components or any other sign of damage. Notify National Instruments if the device appears damaged in any way. Do not install a damaged device.

• Never touch the exposed pins of connectors.

Optional Equipment

If your application requires that you use transducers with microdot connectors, use the BNC plug screw-on receptacle, part number 033-0101-0001, from Microdot Connector Company. This accessory allows you to conect BNC and microdot connectors.

BNC-2140 User Manual 1-2

National Instruments Corporation

Custom Cabling

Chapter 1 Introduction

If your application requires that you use a prepolarized microphone with a microphone preamplifier, contact Brüel and Kjær.

National Instruments offers cables of different lengths for the BNC-2140 accessory to connect your analog I/O signals to the DSA devices. National Instruments recommends that you not develop your own cabling solution due to the high-density connector that is required and the necessity to maintain high signal integrity.

If your application requires you to develop your own cable, use the following guidelines:

• Use shielded twisted-pair wires for each differential analog input or output channel pair . Since the signals are differential, using this type of wire yields the best results.

• When connecting the cable shields, be sure to connect the analog input grounds to the AIGND pins and the analog output grounds to the AOGND pin s. For a co nnector pino ut descripti on refer to Table 3-2 in Chapter 3, Signal Connections.

• You can create your own accessories by using a 68-pin very high density cable interconnect (VHDCI) receptacle header using AMP 68-position right-angle PWB receptacle header 787254-1.

• Recommended manufacturer part numbers for the 68-pin mating connector (for the cable assembly) are as follows:

– AMP 68-position cable straight plug, part number 787131-3 – AMP 68-position backshell with jackscrews, part number

787191-1

National Instruments Corporation 1-3 BNC-2140 User Manual

Installation and Configuration

This chapter explains how to install and configure your BNC-2140 accessory.

Installation

Note

You must turn the power off to your computer before installing the BNC-2140.

The following are general installation instructions.

1. Insert either end of your SHC68-C68-A1 analog cable into the 68-pin connector on the BNC-2140. Insert the other end into the 68-pin connector on the DSA plug-in device.

2. Tighten the jack screws finger-tight on both ends of the cable.

3. Check the installation.

4. Turn on your computer.

The BNC-2140 accessory is now installed.

Device Configuration

You must manually configure the BNC-2140 accessory by setting the channel switches. You can configure each input channel to have ICP signal conditioning enabled or disabled, and for DIFF and SE measurements. Y ou can also configure each output channel for DIFF or SE measurements. You can turn the power on or off for the ICP signal conditioning circuitry. If you do not require ICP signal conditioning, turn off the ICP power. Refer to Figure 2-1 for the location of the switches.

Note

You can connect or disconnect BNC cables carrying signals without turning off the computer.

National Instruments Corporation 2-1 BNC-2140 User Manual

Chapter 2 Installation and Configuration

Figure 2-1. Switch Settings and Signal Connections

BNC-2140 User Manual 2-2

National Instruments Corporation

Signal Connections

This chapter describes how to connect input and output signals to your BNC-2140.

You can connect the external analog signals through six BNC connectors. Four BNC connectors are for input signals and two connectors are for output signals.

The SHC68-C68-A1 shielded cable connects the BNC-2140 internal analog signal connector to the DSA plug-in device. A single 68-pin 0.8 mm VHDCI connector connects the analog I/O signals to the shielded cable.

I/O Connectors

Table 3-1 shows the pin assignments for the six external I/O BNC connectors.

Table 3-1.

Signal Name Reference Direction Description

+ACH<0..3> AIGND Input +Analog Input Channel 0 through 3—Each channel

–ACH<0..3> AIGND Input

+DAC0OUT –DAC0OUT Output +Analog Output Channel 0—This pin supplies the

–DAC0OUT +DAC0OUT Output

National Instruments Corporation 3-1 BNC-2140 User Manual

BNC Analog I/O Connector Signal Descriptions

can have ICP enabled or disabled. This signal passes through the BNC internal conductor.

–Analog Input Channel 0 through 3—In SE mode the inverting (–) terminal is tethered to ground through a 50 Ω resistor. This signal passes through the external BNC shell.

analog non-inverting output channel 0. This signal passes through the internal BNC conductor.

–Analog Output Channel 0—This pin supplies the analog inverting output channel 0. This signal passes through the external BNC shell. In SE mode, the inverting (–) terminal is tethered to ground through a 50 Ω resistor.

Chapter 3 Signal Connections

Table 3-1. BNC Analog I/O Connector Signal Descriptions (Continued)

Signal Name Reference Direction Description

+DAC1OUT –DAC1OUT Output +Analog Output Channel 1—This pin supplies the

analog non-inverting output channel 1. This signal passes through the internal BNC conductor.

–DAC1OUT +DAC1OUT Output

–Analog Output Channel 1—This pin supplies the analog inverting output channel 1. This signal passes through the external BNC shell. In SE mode, the inverting (–) terminal is tethered to ground through a 50 Ω resistor.

BNC-2140 User Manual 3-2

National Instruments Corporation

Chapter 3 Signal Connections

Figure 3-1 describes the pin connections on the BNC-2140 68-pin connector.

NC NC

NC NC NC NC NC

NC NC

NC NC NC NC

†

135 236 337 438 539 640 741 842

943 10 44 11 45 12 46 13 47 14 48 15 49 16 50 17 51 18 52 19 53 20 54 21 55 22 56 23 57 24 58 25 59 26 60 27 61 28 62 29 63 30 64 31 65 32 66 33 67 34 68

+ACH0 AIGND +ACH1 AIGND +ACH2 AIGND +ACH3 AIGND NC NC NC NC NC NC NC NC NC

NC NC

NC NC NC NC NC +DAC0OUT AOGND +DAC1OUT AOGND NC NC NC NC +5 V DGND

–ACH0

AIGND

–ACH1

AIGND

–ACH2

AIGND

–ACH3

AIGND

–DAC0OUT

AOGND

–DAC1OUT

AOGND

+5 V

DGND

†

These AIGND and AOGND pins are not connected in the SHC6868-A1 cable

Figure 3-1. BNC-2140 External 68-Pin Analog Connector

National Instruments Corporation 3-3 BNC-2140 User Manual

Chapter 3 Signal Connections

Note This BNC-2140 pin assignment maps to the pin assignment of the DSA device you

are connecting to the BNC-2140. Refer to your DSA device user manual for the pin assignments specific to your device connection.

Table 3-2 shows the pin assignments for the internal 68-pin I/O connector.

Table 3-2. 68-Pin Analog I/O Connector Signal Descriptions

Signal Name Reference Direction Description

AIGND — — Analog Input Ground—These pins are the reference

point for single-ended measurements in SE mode and the bias current return point for differential

measurements. +ACH<0..3> AIGND Input +Analog Input Channel 0 through 3. –ACH<0..3> AIGND Input

–Analog Input Channel 0 through 3. +DAC0OUT –DAC0OUT Output +Analog Output Channel 0. –DAC0OUT +DAC0OUT Output

–Analog Output Channel 0. +DAC1OUT –DAC1OUT Output +Analog Output Channel 1. –DAC1OUT +DAC1OUT Output

–Analog Output Channel 1. AOGND — — Analog Output Ground—The analog output

voltages are ultimately referenced to this node. DGND — — Digital Ground—This pin supplies the reference for

the +5 VDC supply. +5 V DGND Output +5 VDC Source—These pins are fused for up to

0.5 A of +5 V supply on the DSA plug-in device.

The fuse is self-resetting. This source powers the

ICP circuits of the BNC-2140.

NOTE:

For +ACH<0..3>, –ACH<0..3>, +DAC0OUT, –DAC0OUT, +DAC1OUT, and –DAC1OUT descriptions see

Table 3-1.

Refer to Figure 3-1 for the pin assignments for the 68-pin connector.

Caution Connections that exceed any of the maximum ratings of input or output signals

on the BNC-2140 accessory can damage not only the BNC-2140, but also the DSA plug-in device and the computer as well. Maximum input ratings for each signal are given in Appendix A, Specifications. National Instruments is not liable for any damages resulting from signal connections exceeding maximum ratings.

BNC-2140 User Manual 3-4

National Instruments Corporation

The outer shell of the BNC connectors is not GND (0 V). The outer shell of the BNC is not physically connected to the metal box of the BNC-2140. The outer shell is either the inverting diff erential signal in DIFF mode or is tethered to GND (0 V) through a 50 Ω, 1 W resistor in SE mode.

Analog Input Signal Connections

The analog input signals for the BNC-2140 device are +ACH<0..3> and –ACH<0..3>. Connecting of analog input signals to your BNC-2140 accessory depends on the configuration of the input signal sources.

For most signals, you use a DIFF configuration and simply connect the signal to +ACHx (where x is the BNC-2140 channel) and the signal ground (or signal minus), as appropriate, to –ACHx. If a signal has a high output impedance (greater than 1 kΩ) and is floating, you may find it useful to use an SE configuration that tethers the signal minus to AIGND. This reduces common-mode interference.

Analog Output Signal Connections

The BNC-2140 analog output signals are +DAC0OUT, –DAC0OUT, +DAC1OUT, and –DAC1OUT.

Chapter 3 Signal Connections

DAC0OUT is the voltage output signal for analog output channel 0.

DAC1OUT is the voltage output signal for analog output channel 1.

Connection of analog output signals from your BNC-2140 accessory depends on the configuration of the devices recei ving the signals. For most signals, you use a DIFF configuration and simply connect +DACxOUT (where x is the BNC-2140 channel) to the signal and –DACxOUT to the signal ground (or signal minus), as appropriate. When driving some floating devices, you may sometimes find it helpful to use the SE configuration and connect the floating ground system of the device to AOGND to reduce common-mode noise coupled from an interfering source to the device.

Caution

National Instruments Corporation 3-5 BNC-2140 User Manual

When you configure an analog output channel in the SE mode, the voltage between AOGND and –D ACxOUT must not exceed ±7.07 V (5 V exceeds this rating can damage the BNC-2140, the DSA plug-in device, and the computer. National Instruments is not responsible for any damages resulting from connections that exceed this rating.

). Voltage that

rms

Theory of Operation

This chapter contains a functional overview of the BNC-2140.

National Instruments Corporation 4-1 BNC-2140 User Manual

Chapter 4 Theory of Operation

Functional Overview

Figure 4-1 is a block diagram of the BNC-2140.

ICP CH0

Isolated Power Supply

+5 V +30 V

ICP Current

Source 0

ICP CH3

Isolated Power Supply

+5 V +30 V

ICP Current

Source 3

ICP Enable

on/off

ICP Enable

on/off

AICH0 BNC Connector

DIFF/SE

AICH3 BNC Connector

DIFF/SE

50 Ω

68-Pin

Connector

AICH0+

AICH0– AIGND

AICH3+

AICH3– AIGND

Figure 4-1.

BNC-2140 User Manual 4-2

DAC0OUT BNC Connector

50Ω

DIFF/SE

DAC1OUT BNC Connector

50 Ω

DIFF/SE

+5 V

ICP Power

on/off

BNC-2140 Block Diagram

DAC0OUT+

DAC0OUT– AOGND

DAC1OUT+

DAC1OUT– AOGND

+5 V DGND

National Instruments Corporation

Analog Input Circuitry

The BNC-2140 has four identical analog input channels. A principal function of the BNC-2140 is to supply a constant current for

ICP type accelerometers and microphone preamplifiers. Many accelerometers use piezoelectric materials to generate a charge that is proportional to the acceleration applied. Although these types of accelerometers have certain advantages, they are very suseptable to external noise. ICP-type sensor manufacturers embed a charge amplifier within the transducer to reduce the effect of cable length, noise, and other spurious effects. The BNC-2140 supplies the constant current required to power that embedded charge amplyfier ICP that allows you to use inexpensive cables such as BNC cables. Leveraging off this technology, some manufacturers use ICP signal conditioning to power their prepolarized microphones. If your application requires a microphone preamplifier for use with a prepolarized microphone see Optional

Equipment, in Chapter 1, for a list of recommended suppliers.

You must enable ICP to generate the required power for each channel that uses these types of accelerometers and microphone preamplifiers. When you disable ICP, the connection from the ICP circuit to the analog input signal breaks and has no impact on the incoming signal. When you disable ICP on an input channel, the circuitry of two channels is still energized. If you do not require ICP to be enabled on any of the four input channels, turn off the ICP power to de-energize the circuitry. Turning off the ICP power removes any noise the circuitry can induce on the incoming signal.

Chapter 4 Theory of Operation

You can also use the BNC-2140 to select between DIFF and SE input modes. The BNC-2140 works with any DSA device that has a differential input stage for each input channel.

In DIFF mode, one line connects to the positive input of the channel, and the other connects to the negative input of that same channel. You can connect the differential input to either floating or ground-referenced signals.

You can use ICP signal conditioning when the BNC-2140 inputs are either in DIFF or SE mode.

National Instruments Corporation 4-3 BNC-2140 User Manual

Chapter 4 Theory of Operation

Analog Output

The BNC-2140 has two analog output channels. The BNC-2140 can also select between DIFF and SE outputs.

In DIFF mode, one line connects to the positive output of the channel and the other connects to the negative output of that same channel. You can connect the differential output to either floating or ground-referenced signals.

BNC-2140 User Manual 4-4

National Instruments Corporation

Specifications

This appendix lists the specifications of the BNC-2140 accessory. All specifications are typical at 25° C unless otherwise noted. All specif ications are relative to measurement standards and require a 15 minute warm-up period. Specifications do not include transducer error.

Analog Input

Voltage Input

Number of channels...............................4

Maximum input voltage

(Signal + common mode voltage).......... Each input should remain within

Inputs affected........................................ACH0, ACH1, ACH2, ACH3

Input coupling........................................DC

±42.4 V (30 V input or of AIGND

) of any other

rms

Input capacitance

DIFF mode

Current excitation on ............... 85 pF

Current excitation off...............75 pF

SE mode

Current excitation on ............... 150 pF

Current excitation off...............145 pF

Current Excitation

Level.......................................................4 mA

Accuracy ................................................±1.31%

Includes the effects of the BNC-2140 with a 1 m SHC68-C68-A1 analog cable

National Instruments Corporation A-1 BNC-2140 User Manual

Appendix A Specifications

Temperature coefficient..........................±141 ppm/° C

Voltage compliance................................24 V

Excitation overvoltage protection...........±42.4 V (30 V

Analog Output

Number of channels................................2, see Caution under Analog

Output coupling......................................DC

Power Requirement (from DSA board)

Power consumption ................................400 mA at +5 VDC

Physical

Dimensions.............................................14.0 by 11.2 by 3.8 cm

I/O connectors

I/O Signals.......................................6 BNC connectors (outer shell

DSA board connection ....................68-pin 0.8 mm VHDCI female

) powered on or

off

Output Signal Connections, in

Chapter 3, Signal Connections

(6.0 by 4.4 by 1.6 in.)

isolated from box metal)

connector

rms

Environment

Operating temperature............................0° to 40° C

Storage temperature................................–55° to 150° C

Relative humidity ...................................5% to 90% non-condensing

BNC-2140 User Manual A-2

National Instruments Corporation

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 fax-on-demand 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: 512 794 5422

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: 01 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, ftp.natinst.com, as anonymous and use your Internet address, such as documents are located in the

National Instruments Corporation B-1 BNC-2140 User Manual

joesmith@anywhere.com, as your password. The support files and

/support directories.

Fax-on-Demand Support

Fax-on-Demand is a 24-hour information retrieval system containing a library of documents on a wide range of technical information. You can access Fax-on-Demand from a touch-tone telephone at 512 418 1111.

E-Mail Support (Currently USA Only)

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

support@natinst.com

Telephone and Fax 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.

Country Telephone Fax

Australia 03 9879 5166 03 9879 6277 Austria 0662 45 79 90 0 0662 45 79 90 19 Belgium 02 757 00 20 02 757 03 11 Brazil 011 288 3336 011 288 8528 Canada (Ontario) 905 785 0085 905 785 0086 Canada ( Denmark 45 76 26 00 45 76 26 02 Finland 09 725 725 11 09 725 725 55 France 01 48 14 24 24 01 48 14 24 14 Germany 089 741 31 30 089 714 60 35 Hong Kong 2645 3186 2686 8505 Israel 03 6120092 03 612 0095 Italy 02 413091 02 41309215 Japan 03 5472 2970 03 5472 2977 Korea 02 596 7456 02 596 7455 Mexico 5 520 2635 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 United Kingdom 01635 523545 01635 523154 United States 512 795 8248 512 794 5678

Québec

) 514 694 8521 514 694 4399

BNC-2140 User Manual B-2

National Instruments Corporation

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BNC-2140 User Manual

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Technical Publications

Glossary

Prefix Meanings Value

p- pico 10 n- nano- 10 µ- micro- 10

m- milli- 10

k- kilo- 10

M- mega- 10

G- giga- 10

t- tera- 10

Numbers/Symbols

% percent

–12

–9

–6

–3

+ positive of, or plus – negative of, or minus /per °degree

Ω ohm +5 V +5 V VDC source signal

A amperes AC alternating current AC coupled allowing the transmission of AC signals while blocking DC signals

National Instruments Corporation G-1 BNC-2140 User Manual

Glossary

ACH analog input channel signal A/D analog-to-digital ADC analog-to-digital converter—an electronic device, often an integrated

circuit, that converts an analog voltage to a digital number

alias a false lower frequency component that appears in sampled data acquired

at too low a sampling rate

amplification a type of signal conditioning that improves accuracy in the resulting

digitized signal and reduces noise

amplitude flatness a measure of how close to constant the gain of a circuit remains over a range

of frequencies AOGND analog output ground signal attenuate to decrease the amplitude of a signal attenuation ratio the factor by which a signal’s amplitude is decreased

b bit—one binary digit, either 0 or 1 B byte—eight related bits of data, an eight-bit binary number. Also used to

denote the amount of memory required to store one byte of data. bandwidth the range of frequencies present in a signal, or the range of frequencies to

which a measuring device can respond bipolar a signal range that includes both positive and negative v alues (for example,

–5 V to +5 V) BNC a type of coaxial signal connector

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National Instruments Corporation

Glossary

C Celsius channel pin or wire lead to which you apply or from which you read the analog or

digital signal. Analog signals can be single-ended or differential. For digital signals, you group channels to form ports. Ports usually consist of either four or eight digital channels.

CMRR common-mode rejection ratio—a measure of an instrument’s ability to

reject interference from a common-mode signal, usually expressed in

decibels (dB) common-mode range the input range over which a circuit can handle a common-mode signal common-mode signal the mathematical average voltage, relativ e to the computer’ s ground, of the

signals from a differential input common-mode voltage any voltage present at the instrumentation amplifier inputs with respect to

amplifier ground compensation range the range of a parameter for which compensating adjustment can be made conversion device device that transforms a signal from one form to another. For example,

analog-to-digital converters (ADCs) for analog input, digital-to-analog

converters (DACs) for analog output, digital input or output ports, and

counter/timers are conversion devices. conversion time the time required, in an analog input or output system, from the moment a

channel is interrogated (such as with a read instruction) to the moment that

accurate data is available coupling the manner in which a signal is connected from one location to another crosstalk an unwanted signal on one channel due to an input on a different channel current drive capability the amount of current a digital or analog output channel is capable of

sourcing or sinking while still operating within voltage range specifications current sinking the ability of a DAQ board to dissipate current for analog or digital output

signals current sourcing the ability of a DAQ board to supply current for analog or digital output

signals

National Instruments Corporation G-3 BNC-2140 User Manual

Glossary

D/A digital-to-analog DAC digital-to-analog converter—an electronic device, often an integrated

circuit, that converts a digital number into a corresponding analog voltage

or current DAC0OUT analog channel 0 output signal DAC1OUT analog channel 1output signal dB decibel—the unit for expressing a logarithmic measure of the ratio of two

signal levels: dB=20log DC direct current DC coupled allowing the transmission of both AC and DC signals default setting a default parameter value recorded in the driver . In many cases, the default

input of a control is a certain value (often 0) that means use the current

default setting. For example, the default input for a parameter may be do

not change current setting, and the default setting may be no AMUX-64T

boards. If you do change the value of such a parameter, the new value

becomes the new setting. You can set default settings for some parameters

in the configuration utility or manually using switches located on the

device.

(V1/V2), for signals in volts

delta-sigma modulating ADC

a high-accuracy circuit that samples at a higher rate and lower resolution

than is needed and (by means of feedback loops) pushes the quantization

noise above the frequency range of interest. This out-of-band noise is

typically removed by digital filters. DGND digital ground signal DIFF differential mode differential input an analog input consisting of two terminals, both of which are isolated from

computer ground, whose difference is measured differential measurement

system

a way you can configure your device to read signals, in which you do not

need to connect either input to a fixed reference, such as the earth or a

building ground DIO digital input/output

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National Instruments Corporation

Glossary

DNL differential nonlinearity—a measure in least significant bit of the

worst-case deviation of code widths from their ideal value of 1 LSB

dynamic range the ratio of the largest signal level a circuit can handle to the smallest signal

level it can handle (usually taken to be the noise level), normally expressed in decibels

EMC electromechanical compliance

floating signal sources signal sources with voltage signals that are not connected to an absolute

reference or system ground. Also called nonreferenced signal sources. Some common example of floating signal sources are batteries, transformers, or thermocouples.

gain the factor by which a signal is amplified, sometimes expressed in decibels gain accuracy a measure of deviation of the gain of an amplifier from the ideal gain g

rms

grounded measurement system

level of random vibration See SE.

h hour hardware the physical components of a computer system, such as the circuit boards,

plug-in boards, chassis, enclosures, peripherals, and cables hex hexadecimal Hz hertz—cycles per second. Specifically refers to the repetition frequency of

a waveform.

National Instruments Corporation G-5 BNC-2140 User Manual

Glossary

IC integrated circuit ICP Integrated Circuit Piezoelectric—identifies products that operate using a

constant current source and returns the output signal in the form of voltage modulation on the same line as the constant current source.

IMD intermodulation distortion—the ratio, in dB, of the total rms signal level of

harmonic sum and difference distortion products, to the overall rms signal level. The test signal is two sine waves added together according to the following standards:

SMPTE—A 60 Hz sine wave and a 7 kHz sine wave added in a 4:1 amplitude ratio.

DIN—A 250 Hz sine wave and an 8 kHz sine wave added in a 4:1 amplitude ratio.

CCIF—A 14 kHz sine wave and a 15 kHz sine wave added in a

1:1 amplitude ratio. in. inches INL integral nonlinearity—a measure in LSB of the worst-case deviation from

the ideal A/D or D/A transfer characteristic of the analog I/O circuitry input bias current the current that flows into the inputs of a circuit input impedance the measured resistance and capacitance between the input terminals of a

circuit input offset current the difference in the input bias currents of the two inputs of an

instrumentation amplifier instrumentation

amplifier

a circuit whose output voltage with respect to ground is proportional to the

difference between the voltages at its two inputs I/O input/output—th e transfer of data to/from a computer system involving

communications channels, operator interface devices, and/or data

acquisition and control interfaces I

current, output high

current, output low

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National Instruments Corporation

k kilo—the standard metric prefix for 1,000, or 103, used with units of

measure such as volts, hertz, and meters

Glossary

K kilo—the prefix for 1,024, or 2

, used with B in quantifying data or

computer memory

kS 1,000 samples

LabVIEW laboratory virtual instrument engineering workbench linearity the adherence of device response to the equation R = KS, where

R = response, S = stimulus, and K = a constant

linearization a type of signal conditioning in which software linearizes the voltage levels

from transducers, so the voltages can be scaled to measure physical phenomena

low frequency corner in an AC-coupled circuit, the frequency belo w which signals are attenuated

by at least 3 dB

m meters M (1) Mega, the standard metric prefix for 1 million or 10

units of measure such as volts and hertz; (2) mega, the prefix for 1,048,576,

or 2

, when used with B to quantify data or computer memory

, when used with

MSB most significant bit MTBF mean time between failure MTTR mean time to repair—predicts downtime and how long it takes to fix a

product

National Instruments Corporation G-7 BNC-2140 User Manual

Glossary

NC normally closed, or not connected NIST National Institute of Standards and Technology noise an undesirable electrical signal—Noise comes from external sources such

as the AC power line, motors, generators, transformers, fluorescent lights,

soldering irons, CR T displays, computers, electrical storms, welders, radio

transmitters, and internal sources such as semiconductors, resistors, and

capacitors. Noise corrupts signals you are trying to send or receive. nonreferenced signal

sources

NRSE nonreferenced single-ended mode—all measurements are made with

signal sources with voltage signals that are not connected to an absolute

reference or system ground. Also called floating signal sources. Some

common example of nonreferenced signal sources are batteries,

transformers, or thermocouples.

respect to a common (NRSE) measurement system reference, but the

voltage at this reference can vary with respect to the measurement system

ground

onboard channels channels provided by the plug-in data acquisition board output settling time the amount of time required for the analog output voltage to reach its final

value within specified limits output slew rate the maximum rate of change of analog output voltage from one level to

another

passband the range of frequencies which a de vice can properly propagate or measure PCI Peripheral Component Interconnect—a high-performance expansion bus

architecture originally developed by Intel to replace ISA and EISA. It is

achieving widespread acceptance as a standard for PCs and work-stations;

it offers a theoretical maximum transfer rate of 132 Mbytes/s.

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National Instruments Corporation

Glossary

peak to peak a measure of signal amplitude; the difference between the highest and

lowest excursions of the signal pF pico farad—a farad is a unit used to measure capacitance ppm parts per million pts points

relative accuracy a measure in LSB of the accuracy of an ADC. It includes all non-linearity

and quantization errors. It does not include offset and gain errors of the

circuitry feeding the ADC. resolution the smallest signal increment that can be detected by a measurement

system. Resolution can be expressed in bits, in proportions, or in percent of

full scale. For example, a system has 12-bit resolution, one part in 4,096

resolution, and 0.0244% of full scale. rise time the difference in time between the 10% and 90% points of a system’s step

response rms root mean square—the square root of the average v alue of the square of the

instantaneous signal amplitude; a measure of signal amplitude RSE see SE

s seconds S samples SE single-ended—a term used to describe an analog input that is measured

with respect to a common ground settling time the amount of time required for a voltage to reach its final value within

specified limits

National Instruments Corporation G-9 BNC-2140 User Manual

Glossary

Shannon Sampling Theorem

SNR signal-to-noise ratio—the ratio of the overall rms signal level to the rms

source impedance a parameter of signal sources that reflects current-driving ability of voltage

SS simultaneous sampling—a property of a system in which each input or

S/s samples per second—used to express the rate at which a DAQ board

system noise a measure of the amount of noise seen by an analog circuit or an ADC when

a law of sampling theory stating that if a continuous bandwidth-limited signal contains no frequency components higher than half the frequency at which it is sampled, then the original signal can be recovered without distortion

noise level, expressed in decibels

sources (lower is better) and the voltage-driving ability of current sources (higher is better)

output channel is digitized or updated at the same instant

samples an analog signal

the analog inputs are grounded

THD total harmonic distortion—the ratio of the total rms signal due to harmonic

distortion to the overall rms signal, in decibel or a per centage

THD+N signal-to-THD plus noise—the ratio in decibels of the overall rms signal to

the rms signal of harmonic distortion plus noise introduced transducer See sensor transducer excitation a type of signal conditioning that uses external voltages and currents to

excite the circuitry of a signal conditioning system into measuring physical

phenomena

unipolar a signal range that is always positive (for example, 0 to +10 V) update rate the number of output updates per second

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National Instruments Corporation

Vvolts

Glossary

ref

volts direct current volts, input high volts, input low volts in volts, output high volts, output low reference voltage

waveform multiple voltage readings taken at a specific sampling rate working voltage the highest voltage that should be applied to a product in normal use,

normally well under the breakdown voltage for safety margin.

National Instruments Corporation G-11 BNC-2140 User Manual

Index

Numbers

+5 V signal, 68-pin connector signal

descriptions (table), 3-4

+ACH<0..3> signal

68-pin connector signal descriptions

(table), 3-4 analog connector (table), 3-1 analog input signal connections, 3-5

–ACH<0..3> signal

68-pin connector signal descriptions

(table), 3-4 analog connector (table), 3-1 analog input signal connections, 3-5

AIGND signal, 68-pin connector signal

descriptions (table), 3-4

analog input

circuitry, 4-3 signal connections, 3-5 specifications, A-1 to A-2

current excitation, A-1 to A-2 voltage input, A-1

analog output

channels, 4-4 signal connections, 3-5 specifications, A-2

AOGND signal, 68-pin connector signal

descriptions (table), 3-4

block diagram of BNC-2140, 4-2 BNC-2140

block diagram, 4-2 custom cabling, 1-3

optional equipment, 1-2 to 1-3 overview, 1-1 requirements for getting started, 1-2 unpacking, 1-2

bulletin board support, B-1

cabling, custom, 1-3 configuration

manual configuration, 2-1 switch settings and signal connections

(figure), 2-2 current excitation specifications, A-1 to A-2 custom cabling, 1-3 customer communication, viii, B-1toB-2

+DAC0OUT signal

68-pin connector signal descriptions

(table), 3-4

analog connector (table), 3-1 analog output signal connections, 3-5

–DAC0OUT signal

68-pin connector signal descriptions

(table), 3-4

analog connector (table), 3-1 analog output signal connections, 3-5

+DAC1OUT signal

68-pin connector signal descriptions

(table), 3-4

analog connector (table), 3-2 analog output signal connections, 3-5

–DAC1OUT signal

68-pin connector signal descriptions

(table), 3-4

analog connector (table), 3-2

National Instruments Corporation I-1 BNC-2140 User Manual

Index

analog output signal connections, 3-5

DGND signal, 68-pin connector signal

descriptions (table), 3-4

DIFF configuration

analog input circuitry, 4-3 analog input signal connections, 3-5 analog output, 4-4 analog output signal connections, 3-5 setting, 2-1 to 2-2

documentation

conventions used in the manual, viii organization of manual, vii related documentation, viii

dynamic signal acquisition boards, 1-1

electronic support services, B-1 to B-2 e-mail support, B-2 environment specifications, A-2 equipment, optional, 1-2 to 1-3

fax and telephone support numbers, B-2 Fax-on-Demand support, B-2 FTP support, B-1 fuse, self-resetting (table), 3-4

ICP

accelerometers and microphone

preamplifiers, 1-1, 4-3 configuring, 2-1 to 2-2 signal conditioning, 1-1, 4-3

installation

device configuration, 2-1 to 2-2 procedure, 2-1 unpacking the BNC-2140, 1-2

I/O connectors, 3-1 to 3-5

68-pin connector signal descriptions

(table), 3-4

analog connector signal descriptions

(table), 3-1to3-2

exceeding maximum ratings (caution),

3-4to3-5

pin connections (figure), 3-3

manual. See documentation.

operation of BNC-2140. See theory of

operation.

optional equipment, 1-2 to 1-3

physical specifications, A-2 pin connections

68-pin analog connector (figure), 3-3 mapping to DSA device (note), 3-4

power requirement specifications, A-2

requirements for getting started, 1-2

SE configuration

analog input circuitry, 4-3 analog input signal connections, 3-5 analog output, 4-4 analog output signal connections, 3-5 setting, 2-1 to 2-2

self-resetting fuse (table), 3-4

BNC-2140 User Manual I-2

National Instruments Corporation

Index

signal connections, 3-1 to 3-5

analog input, 3-5

analog output, 3-5

I/O connectors, 3-1 to 3-5

68-pin connector signal descriptions

(table), 3-4

analog connector signal descriptions

(table), 3-1to3-2

exceeding maximum ratings

(caution), 3-4 to 3-5

pin connections (figure), 3-3

switch settings and signal connections

(figure), 2-2

specifications, A-1 to A-2

analog input, A-1 to A-2

current excitation, A-1 to A-2

voltage input, A-1 analog output, A-2 environment, A-2 physical, A-2 power requirements, A-2

switch settings and signal connections

(figure), 2-2

technical support, B-1 to B-2 telephone and fax support numbers, B-2 theory of operation, 4-1 to 4-4

analog input circuitry, 4-3 analog output, 4-4 block diagram of BNC-2140, 4-2 functional overview, 4-2

unpacking the BNC-2140, 1-2

voltage input specifications, A-1

National Instruments Corporation I-3 BNC-2140 User Manual

National Instruments BNC-2140 User Manual

Specifications and Main Features

Frequently Asked Questions

User Manual

BNC-2140 User Manual

International Offices

Important Information

Warranty

Copyright

Trademarks

Contents

Figures

Tables

About This Manual

Organization of This Manual

Conventions Used in This Manual

Related Documentation

Customer Communication

What You Need to Get Started

Unpacking

Optional Equipment

Custom Cabling

Installation

Device Configuration

Figure 2-1. Switch Settings and Signal Connections

I/O Connectors

Analog Input Signal Connections

Analog Output Signal Connections

Functional Overview

Analog Input Circuitry

Analog Output

Glossary

Index