National Instruments BNC -2140 User Manual

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BNC-2140 User Manual

Dynamic Signal Acquisition Signal Conditioning Accessory

BNC-2140 User Manual

February 2001 Edition

Part Number 321933C-01

Worldwide Technical Support and Product Information

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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 defective during the warranty period. This warranty includes parts and labor.

The media on which you receive National Instruments software are warranted not to fail to execute programming instructions, due to defects in materials and workmanship, for a period of 90 days from date of shipment, as evidenced by receipts or other documentation. National Instruments will, at its option, repair or replace software media that do not execute programming instructions if National Instruments receives notice of such defects during the warranty period. National Instruments does not warrant that the operation of the software shall be uninterrupted or error free.

A Return Material Authorization (RMA) number must be obtained from the factory and clearly marked on the outside of the package before any equipment will be accepted for warranty work. National Instruments will pay the shipping costs of returning to the owner parts which are covered by warranty.

National Instruments believes that the information in this document is accurate. The document has been carefully reviewed for technical accuracy. In the event that technical or typographical errors exist, National Instruments reserves the right to make changes to subsequent editions of this document without prior notice to holders of this edition. The reader should consult National Instruments if errors are suspected. In no event shall National Instruments be liable for any damages arising out of or related to this document or the information contained in it.

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MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE

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DAMAGES RESULTING FROM LOSS OF DATA

. This limitation of the liability of National Instruments will apply regardless ofthe form of action, whether in contract ortort, including

THEREOF

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, PROFITS, USE OF PRODUCTS, OR INCIDENTAL OR CONSEQUENTIAL DAMAGES, EVEN IF ADVISED OF THE POSSIBILITY

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Product and company names mentioned herein are trademarks or trade names of their respective companies.

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Conventions

The following conventions are used in this manual:

<> Angle brackets that contain numbers separated by an ellipsis represent a

range of values associated with a bit or signal name—for example, ACH<3..0>.

This icon denotes a note, which alerts you to important information.

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

italic Italic text denotes variables, emphasis, or a cross reference.

monospace

Text in this font denotes text or characters that you should enter from the keyboard, sections of code, programming examples, and syntax examples. This font is also used for the proper names of disk drives, paths, directories, programs, subprograms, subroutines, device names, functions, operations, variables, filenames and extensions, and code excerpts.

Chapter 1 Introduction

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

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

Optional Equipment.......................................................................................................1-3

Chapter 2 Installation and Configuration

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

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

Chapter 3 Signal Connections

I/O Connectors...............................................................................................................3-2

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

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

Chapter 4 Theory of Operation

Functional Overview...................................................................................................... 4-1

Analog Input Circuitry...................................................................................................4-2

Analog Output................................................................................................................4-3

Appendix A Specifications

Appendix B Technical Support Resources

Contents

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 ................................................................... 4-1

Tables

Table 3-1. BNC Analog I/O Connector Signal Descriptions ................................. 3-2

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

BNC-2140 User Manual vi ni.com

Introduction

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

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.

The BNC-2140 is a signal conditioning accessory specifically designed for use with a dynamic signal acquisition (DSA) 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 has 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. With ICP disabled, a BNC-2140 input channel 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 is tethered to a clean analog ground through a 50 Ω resistor.

)

The BNC-2140 receives power for ICP signal conditioning from the DSA plug-in device through 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.

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 and its documentation:

– NI 4451 for PCI

– NI 4452 for PCI

– NI 4551for PCI

– NI 4552 for PCI

❑

This manual

❑

Your computer

❑

SHC68-C68-A1 analog cable

Unpacking

For more information, refer to Instruments Application Note 25, Field Wiring and Noise Considerations.

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 with 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.

• Never touch exposed connector pins.

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 into your computer.

ni.com/appnotes.nsf/

for the National

BNC-2140 User Manual 1-2 ni.com

Optional Equipment

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

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

Chapter 1 Introduction

Installation and Configuration

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

Installation

Caution

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 jackscrews 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. When ICP signal conditioning is enabled large DC offset voltages can occur on signal inputs due to the output bias voltage requirements of the ICP transducer you are using. To remove this offset you must enable AC coupling on the affected input channels of the DSA device. You 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.

Chapter 2 Installation and Configuration

Figure 2-1. Switch Settings and Signal Connections

BNC-2140 User Manual 2-2 ni.com

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 of the BNC connectors are for input signals and two of them 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.

Chapter 3 Signal Connections

I/O Connectors

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

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

Signal Name Reference Direction Description

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

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

–ACH<0..3> AIGND Input

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

–DAC0OUT +DAC0OUT Output

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

–DAC1OUT +DAC1OUT Output

–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.

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

–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 ni.com

Chapter 3 Signal Connections

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

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

+DAC0OUT

AOGND

+DAC1OUT

AOGND

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 SHC68-C68-A1 cable

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

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 describes the signals 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

AOG ND — — 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>, + DAC0O UT, –DAC0OUT, +DAC1OUT, and –DAC1OUT descriptions, see Ta bl e 3 -1 .

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

BNC-2140 User Manual 3-4 ni.com

Chapter 3 Signal Connections

Caution

on the BNC-2140 accessory can damage not only the BNC-2140 but also the DSA plug-in device and the computer. 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.

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

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. In DIFF mode, the outer shell is the inverting differential signal; in SE mode, the outer shell is tethered to GND (0 V) through a 50 Ω, 1 W resistor.

Analog Input Signal Connections

The analog input signals for the BNC-2140 device are +ACH<0..3> and –ACH<0..3>. How you connect 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.

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

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

The way you connect analog output signals from your BNC-2140 accessory depends on the configuration of the devices receiving 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 devices with floating grounds, 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.

Chapter 3 Signal Connections

Caution

between AOGND and –DACxOUT must not exceed ±7.07 V (5 V

When you configure an analog output channel in the SE mode, the voltage

). Voltage that exceeds

rms

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.

BNC-2140 User Manual 3-6 ni.com

Theory of Operation

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

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

On/Off

ICP

On/Off

AICH0 BNC Connector

DIFF/SE

AICH3 BNC Connector

DIFF/SE

DAC0OUT BNC Connector

DIFF/SE

DAC1OUT BNC Connector

DIFF/SE

+5 V

ICP Power

On/Off

50 Ω

68-Pin

Connector

AICH0+

Ω

AICH0– AIGND

AICH3+

AICH3– AIGND

DAC0OUT+

DAC0OUT– AOGND

DAC1OUT+

DAC1OUT– AOGND

+5 V DGND

Figure 4-1. BNC-2140 Block Diagram

Chapter 4 Theory of Operation

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 susceptible to external noise. ICP-type sensor manufacturers embed a charge amplifier within the sensor to reduce the effect of cable length, noise, and other spurious effects. The BNC-2140 supplies the constant current required to power the embedded charge amplifier in the ICP sensor that allows you to use inexpensive cables such as BNC cables. Taking advantage of 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 the Optional

Equipment section in Chapter 1, Introduction, for a supplier

recommendation.

If you attach an ICP-type of accelerometer or microphone preamplifier to an analog input channel, you must turn on the BNC-2140 ICP power switch and enable the ICP circuit for that channel in order to generate the required power. The ICP circuitry of any input channel can be enabled or disabled independently of that of any other input channel. When you disable ICP for a channel, the connection from the ICP circuit to that channel breaks and has no effect on the incoming signal for that channel. If you do not require ICP to be enabled on any of the four input channels, disable ICP on all four channels and 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.

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 in either DIFF or SE mode.

BNC-2140 User Manual 4-2 ni.com

Analog Output

Chapter 4 Theory of Operation

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.

Specifications

This appendix lists the specifications of the BNC-2140 accessory. All specifications are typical at 25 °C unless otherwise noted. All specifications 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

±42.4V(30V input or of AIGND

rms

) of any other

Input capacitance

Input Mode

DIFF 85 pF 75 pF

SE 150 pF 145 pF

Current Excitation

On Off

Current Excitation

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

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

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

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

Appendix A Specifications

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

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

Analog Output

Number of channels................................2 (See the Caution in the Analog

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

Power Requirement (from DSA device)

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

Physical

Dimensions .............................................14.4 by 11.2 by 5.5 cm

I/O connectors

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

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

) powered on

rms

or off

Output Signal Connections

section in Chapter 3,

Signal Connections.)

(5.7by4.4by2.2in.)

isolated from box metal)

connector

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 ni.com

Technical Support Resources

Web Support

National Instruments Web support is your first stop for help in solving installation, configuration, and application problems and questions. Online problem-solving and diagnostic resources include frequently asked questions, knowledge bases, product-specific troubleshooting wizards, manuals, drivers, software updates, and more. Web support is available through the Technical Support section of

NI Developer Zone

ni.com

The NI Developer Zone at building measurement and automation systems. At the NI Developer Zone, you can easily access the latest example programs, system configurators, tutorials, technical news, as well as a community of developers ready to share their own techniques.

Customer Education

National Instruments provides a number of alternatives to satisfy your training needs, from self-paced tutorials, videos, and interactive CDs to instructor-led hands-on courses at locations around the world. Visit the Customer Education section of syllabi, training centers, and class registration.

System Integration

If you have time constraints, limited in-house technical resources, or other dilemmas, you may prefer to employ consulting or system integration services. You can rely on the expertise available through our worldwide network of Alliance Program members. To find out more about our Alliance system integration solutions, visit the System Integration section of

ni.com

ni.com/zone

ni.com

is the essential resource for

for online course schedules,

Appendix B Technical Support Resources

Worldwide Support

National Instruments has offices located around the world to help address your support needs. You can access our branch office Web sites from the Worldwide Offices section of up-to-date contact information, support phone numbers, e-mail addresses, and current events.

If you have searched the technical support resources on our Web site and still cannot find the answers you need, contact your local office or National Instruments corporate. Phone numbers for our worldwide offices are listed at the front of this manual.

ni.com

. Branch office Web sites provide

BNC-2140 User Manual B-2 ni.com

Glossary

Prefix Meanings Value

p- pico- 10

m- milli- 10

k- kilo- 10

M- mega- 10

Numbers/Symbols

% percent

+ positive of, or plus

– negative of, or minus

/per

° degree

–12

–3

Ω ohm

+5 V +5 VDC source signal

A amperes

AC alternating current

AC coupled allowing the transmission of AC signals while blocking DC signals

ACH analog input channel signal

ADC analog-to-digital converter—an electronic device, often an integrated

circuit, that converts an analog voltage to a digital number

AOGND analog output ground signal

Glossary

BNC a type of coaxial signal connector

CCelsius

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

common-mode signal the mathematical average voltage, relative 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

coupling the manner in which a signal is connected from one location to another

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 excitation a source that supplies the current needed by a sensor for its proper operation

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 1 output signal

DC direct current

DC coupled allowing the transmission of both AC and DC signals

DGND digital ground signal

DIFF differential mode

BNC-2140 User Manual G-2 ni.com

Glossary

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

F farads—a unit of capacitance

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

reference or system ground–also called nonreferenced signal sources; common examples are batteries, transformers, or thermocouples

grounded measurement system

See SE.

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

plug-in boards, chassis, enclosures, peripherals, and cables

IC integrated circuit

ICP Integrated Circuit Piezoelectric—identifies products that operate using a

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

in. inches

input bias current the current that flows into the inputs of a circuit

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

instrumentation amplifier

Glossary

instrumentation amplifier

I/O input/output—the transfer of data to/from a computer system involving

a circuit whose output voltage with respect to ground is proportional to the difference between the voltages at its two inputs

communications channels, operator interface devices, and/or data acquisition and control interfaces

m meters

NC normally closed, or not connected

noise an undesirable electrical signal—comes from external sources such as the

AC power line, motors, generators, transformers, fluorescent lights, soldering irons, CRT displays, computers, electrical storms, welders, radio transmitters, and internal sources such as semiconductors, resistors, and capacitors; corrupts signals you are trying to send or receive

nonreferenced signal sources

signal sources with voltage signals that are not connected to an absolute reference or system ground–also called floating signal sources; common examples are batteries, transformers, or thermocouples

PCI Peripheral Component Interconnect—a high-performance expansion bus

architecture originally developed by Intel to replace ISA and EISA; offers a theoretical maximum transfer rate of 132 Mbytes/s and is achieving widespread acceptance as a standard for PCs and work-stations

pF picofarad—one-trillionth of a farad

ppm parts per million

rms root mean square—the square root of the average value of the square of the

instantaneous signal amplitude; a measure of signal amplitude

BNC-2140 User Manual G-4 ni.com

Glossary

s seconds

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

with respect to a common ground

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

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

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

the analog inputs are grounded

transducer a device that responds to a physical stimulus (heat, light, sound, pressure,

motion, flow, and so on), and produces a corresponding electrical signal

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

V volts

VDC volts direct current

rms

Vo l t s R M S

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), 3-2 analog input signal connections, 3-5

–ACH<0..3> signal

68-pin connector signal descriptions

(table), 3-4 analog connector (table), 3-2 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 optional equipment, 1-3

overview, 1-1 requirements for getting started, 1-2 unpacking, 1-2

bulletin board support, B-1

configuration

manual configuration, 2-1 switch settings and signal connections

(figure), 2-2 current excitation specifications, A-1 to A-2 customer communication, B-1 to B-2

+DAC0OUT signal

68-pin connector signal descriptions

(table), 3-4

analog connector (table), 3-2 analog output signal connections, 3-5 to 3-6

–DAC0OUT signal

68-pin connector signal descriptions

(table), 3-4

analog connector (table), 3-2 analog output signal connections, 3-5 to 3-6

+DAC1OUT signal

68-pin connector signal descriptions

(table), 3-4

analog connector (table), 3-2 analog output signal connections, 3-5 to 3-6

–DAC1OUT signal

68-pin connector signal descriptions

(table), 3-4

analog connector (table), 3-2 analog output signal connections, 3-5 to 3-6

DGND signal, 68-pin connector signal

descriptions (table), 3-4

Index

DIFF configuration

analog input circuitry, 4-3 analog input signal connections, 3-5 analog output, 4-4 analog output signal connections,

3-5 to 3-6

setting, 2-1 to 2-2

documentation

conventions used in the manual, iv organization of manual, v related documentation, 1-2

dynamic signal acquisition devices, 1-1

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

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 3-6

68-pin connector signal descriptions

(table), 3-4 analog connector signal descriptions

(table),3-1to3-2

exceeding maximum ratings

(caution), 3-5

pin connections (figure), 3-3

manual. See documentation.

operation of BNC-2140. See theory of

operation.

optional equipment, 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,

3-5to3-6

setting, 2-1 to 2-2 self-resetting fuse (table), 3-4 signal connections, 3-1 to 3-6

analog input, 3-5

analog output, 3-5 to 3-6

BNC-2140 User Manual I-2 ni.com

Index

I/O connectors, 3-1 to 3-6

68-pin connector signal descriptions

(table), 3-4

analog connector signal descriptions

(table), 3-2

exceeding maximum ratings

(caution), 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 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, 4-1 to 4-2

unpacking the BNC-2140, 1-2

voltage input specifications, A-1

National Instruments BNC -2140 User Manual

Specifications and Main Features

Frequently Asked Questions

User Manual

BNC-2140 User Manual

Worldwide Technical Support and Product Information

National Instruments Corporate Headquarters

Worldwide Offices

Important Information

Warranty

Copyright

Trademarks

WARNING REGARDING USE OF NATIONAL INSTRUMENTS PRODUCTS

Contents

Figures

Tables

What You Need to Get Started

Unpacking

Optional Equipment

Installation

Device Configuration

Figure 2-1. Switch Settings and Signal Connections

I/O Connectors

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

Analog Input Signal Connections

Analog Output Signal Connections

Functional Overview

Figure 4-1. BNC-2140 Block Diagram

Analog Input Circuitry

Analog Output

Glossary

Numbers/Symbols

Index

Numbers