National Instruments NI PCI-5911 User Manual

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Modular Instrumentation

NI PCI-5911 User Manual

High-Speed Digitizer with Flex ADC

NI PCI-5911 User Manual

™

March 2003 Edition

Part Number 322150E-01

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For further support information, refer to the Technical Support and Professional Services appendix. To comment on the documentation, send email to techpubs@ni.com.

Important Information

Warranty

The NI 5911 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.

XCEPT AS SPECIFIED HEREIN, NATIONAL INSTRUMENTS MAKES NO WARRANTIES, EXPRESS OR IMPLIED, AND SPECIFICALLY DISCLAIMS ANY WAR RANTY OF

MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE . CUSTOMER’S RIGHT TO RECOVER DAMAGES CAUSED BY FAULT OR NEGLIGENCE ON THE PART OF

ATIONAL INSTRUMENTS SHALL BE LIMITED TO THE AMOUNT THERETOFORE PAID BY THE CUSTOMER. NATIONAL INSTRUMENTS WILL NOT BE LIABLE FOR DAMAGES RESULTING FROM LOSS OF DATA, PROFITS, USE OF PRODUCTS, OR INCIDENTAL OR CONSEQUENTIAL DAMAGES, EVEN IF ADVISED OF THE POSS IBILITY THEREOF. This limitation of the liability of National Instruments will apply regardless of the form of action, whether in contract or tort, including

negligence. Any action against National Instruments must be brought within one year after the cause of action accrues. National Instruments shall not be liable for any delay in performance due to causes beyond its reasonable control. The warranty provided herein does not cover damages, defects, malfunctions, or service failures caused by owner’s failure to follow the National Instruments installation, operation, or maintenance instructions; owner’s modification of the product; owner’s abuse, misuse, or negligent acts; and power failure or surges, fire, flood, accident, actions of third parties, or other events outside reasonable control.

Copyright

Under the copyright laws, this publication may not be reproduced or transmitted in any form, electronic or mechanical, including photocopying, recording, storing in an information retrieval system, or translating, in whole or in part, without the prior written consent of National Instruments Corporation.

Trademarks

CVI™, DAQPad™, Flex ADC™, LabVIEW™, National Instruments™, NI™, ni.com™, NI-DAQ™, RTSI™, and SCXI™ are trademarks of National Instruments Corporation.

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

Patents

For patents covering National Instruments products, refer to the appropriate location: Help»Patents in your software, the patents.txt file on your CD, or

ni.com/patents.

WARNING REGARDING USE OF NATIONAL INSTRUMENTS PRODUCTS

(1) NATIONAL INSTRUMENTS PRODUCTS ARE NOT DESIGNED WITH COMPONENTS AND TESTING FOR A LEVEL OF RELIABILITY SUITABLE FOR USE IN OR IN CONNECTION WITH SURGICAL IMPLANTS OR AS CRITICAL COMPONENTS IN ANY LIFE SUPPORT SYSTEMS WHOSE FAILURE TO PERFORM CAN REASONABLY BE EXPECTED TO CAUSE SIGNIFICANT INJURY TO A HUMAN.

(2) IN ANY APPLICATION, INCLUDING THE ABOVE, RELIABILITY OF OPERATION OF THE SOFTWARE PRODUCTS CAN BE IMPAIRED BY ADVERSE FACTORS, INCLUDING BUT NOT LIMITED TO FLUCTUATIONS IN ELECTRICAL POWER SUPPLY, COMPUTER HARDWARE MALFUNCTIONS, COMPUTER OPERATING SYSTEM SOFTWARE FITNESS, FITNESS OF COMPILERS AND DEVELOPMENT SOFTWARE USED TO DEVELOP AN APPLICATION, INSTALLATION ERRORS, SOFTWARE AND HARDWARE COMPATIBILITY PROBLEMS, MALFUNCTIONS OR FAILURES OF ELECTRONIC MONITORING OR CONTROL DEVICES, TRANSIENT FAILURES OF ELECTRONIC SYSTEMS (HARDWARE AND/OR SOFTWARE), UNANTICIPATED USES OR MISUSES, OR ERRORS ON THE PART OF THE USER OR APPLICATIONS DESIGNER (ADVERSE FACTORS SUCH AS THESE ARE HEREAFTER COLLECTIVELY TERMED “SYSTEM FAILURES”). ANY APPLICATION WHERE A SYSTEM FAILURE WOULD CREATE A RISK OF HARM TO PROPERTY OR PERSONS (INCLUDING THE RISK OF BODILY INJURY AND DEATH) SHOULD NOT BE RELIANT SOLELY UPON ONE FORM OF ELECTRONIC SYSTEM DUE TO THE RISK OF SYSTEM FAILURE. TO AVOID DAMAGE, INJURY, OR DEATH, THE USER OR APPLICATION DESIGNER MUST TAKE REASONABLY PRUDENT STEPS TO PROTECT AGAINST SYSTEM FAILURES, INCLUDING BUT NOT LIMITED TO BACK-UP OR SHUT DOWN MECHANISMS. BECAUSE EACH END-USER SYSTEM IS CUSTOMIZED AND DIFFERS FROM NATIONAL INSTRUMENTS' TESTING PLATFORMS AND BECAUSE A USER OR APPLICATION DESIGNER MAY USE NATIONAL INSTRUMENTS PRODUCTS IN COMBINATION WITH OTHER PRODUCTS IN A MANNER NOT EVALUATED OR CONTEMPLATED BY NATIONAL INSTRUMENTS, THE USER OR APPLICATION DESIGNER IS ULTIMATELY RESPONSIBLE FOR VERIFYING AND VALIDATING THE SUITABILITY OF NATIONAL INSTRUMENTS PRODUCTS WHENEVER NATIONAL INSTRUMENTS PRODUCTS ARE INCORPORATED IN A SYSTEM OR APPLICATION, INCLUDING, WITHOUT LIMITATION, THE APPROPRIATE DESIGN, PROCESS AND SAFETY LEVEL OF SUCH SYSTEM OR APPLICATION.

Compliance

FCC/Canada Radio Frequency Interference Compliance

Determining FCC Class

The Federal Communications Commission (FCC) has rules to protect wireless communications from interference. The FCC places digital electronics into two classes. These classes are known as Class A (for use in industrial-commercial locations only) or Class B (for use in residential or commercial locations). All National Instruments (NI) products are FCC Class A products.

Depending on where it is operated, this Class A product could be subject to restrictions in the FCC rules. (In Canada, the Department of Communications (DOC), of Industry Canada, regulates wireless interference in much the same way.) Digital electronics emit weak signals during normal operation that can affect radio, television, or other wireless products.

All Class A products display a simple warning statement of one paragraph in length regarding interference and undesired operation. The FCC rules have restrictions regarding the locations where FCC Class A products can be operated.

Consult the FCC Web site at

FCC/DOC Warnings

This equipment generates and uses radio frequency energy and, if not installed and used in strict accordance with the instructions in this manual and the CE marking Declaration of Conformity*, may cause interference to radio and television reception. Classification requirements are the same for the Federal Communications Commission (FCC) and the Canadian Department of Communications (DOC).

Changes or modifications not expressly approved by NI could void the user’s authority to operate the equipment under the FCC Rules.

Class A

Federal Communications Commission

This equipment has been tested and found to comply with the limits for a Class A digital device, pursuant to part 15 of the FCC Rules. These limits are designed to provide reasonable protection against harmful interference when the equipment is operated in a commercial environment. This equipment generates, uses, and can radiate radio frequency energy and, if not installed and used in accordance with the instruction manual, may cause harmful interference to radio communications. Operation of this equipment in a residential area is likely to cause harmful interference in which case the user is required to correct the interference at their own expense.

www.fcc.gov for more information.

Canadian Department of Communications

This Class A digital apparatus meets all requirements of the Canadian Interference-Causing Equipment Regulations. Cet appareil numérique de la classe A respecte toutes les exigences du Règlement sur le matériel brouilleur du Canada.

Compliance to EU Directives

Readers in the European Union (EU) must refer to the manufacturer’s Declaration of Conformity (DoC) for information* pertaining to the CE marking compliance scheme. The manufacturer includes a DoC for most hardware products except for those bought from OEMs. In addition, DoCs are usually not provided if compliance is not required, for example electrically benign apparatus or cables.

To obtain the DoC for this product, click Declaration of Conformity at by product family. Select the appropriate product family, followed by your product, and a link to the DoC appears in Adobe Acrobat format. Click the Acrobat icon to download or read the DoC.

* The CE marking Declaration of Conformity contains important supplementary information and instructions for the user or

installer.

ni.com/hardref.nsf/. This Web site lists the DoCs

About This Manual

Conventions ...................................................................................................................vii

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

Safety Information .........................................................................................................viii

Chapter 1 Introduction

Installing the NI 5911 ....................................................................................................1-1

Connecting Signals ........................................................................................................1-1

Acquiring Data with the NI 5911 ..................................................................................1-3

Programmatically Controlling the NI 5911 .....................................................1-3

Interactively Controlling the NI 5911 with the Scope Soft Front Panel .........1-4

Chapter 2 Hardware Overview

Differential Programmable Gain Input Amplifier (PGIA) ............................................2-1

Differential Input .............................................................................................2-1

Input Ranges....................................................................................................2-3

Input Impedance ..............................................................................................2-3

Input Protection ...............................................................................................2-4

AC Coupling....................................................................................................2-4

Conventional and Flexible Resolution Modes ...............................................................2-5

Conventional Mode .........................................................................................2-5

Sampling Methods...........................................................................................2-5

Flexible Resolution Mode ...............................................................................2-6

Calibration .....................................................................................................................2-7

Self-Calibrating the NI 5911 ...........................................................................2-7

When Self-Calibration Is Needed....................................................................2-7

What Self-Calibration Does ............................................................................2-7

External Calibration.........................................................................................2-8

Triggering and Arming ..................................................................................................2-8

Analog Trigger Circuit ....................................................................................2-9

Trigger Holdoff ...............................................................................................2-10

Grounding Considerations ................................................................2-2

Input Bias ..........................................................................................2-4

How Flexible Resolution Works.......................................................2-6

Why Warnings Occur During Acquisition........................................2-8

Contents

Memory ......................................................................................................................... 2-10

Triggering and Memory Usage ....................................................................... 2-10

Multi-Record Acquisitions ............................................................................................ 2-11

RTSI Bus and Clock PFI ............................................................................................... 2-11

PFI Lines ......................................................................................................... 2-11

PFI Lines as Inputs ...........................................................................2-12

PFI Lines as Outputs......................................................................... 2-12

Synchronization .............................................................................................. 2-12

Appendix A Specifications

Appendix B Technical Support and Professional Services

Glossary

Index

NI PCI-5911 User Manual vi ni.com

About This Manual

The NI 5911 User Manual provides information on installing, connecting signals to, and acquiring data from your NI 5911 high-speed digitizer. This manual includes an overview of the NI 5911 and explains the operation of each functional unit of the NI 5911.

Conventions

The following conventions appear 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, DIO<3..0>.

» The » symbol leads you through nested menu items and dialog box options

to a final action. The sequence File»Page Setup»Options directs you to pull down the File menu, select the Page Setup item, and select Options from the last dialog box.

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.

bold Bold text denotes items that you must select or click in the software, such

as menu items and dialog box options. Bold text also denotes parameter names.

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

to a key concept. This font also denotes text that is a placeholder for a word or value that you must supply.

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.

About This Manual

Safety Information

This section contains important safety information that you must follow when installing and using the device.

Do not operate the device in a manner not specified in this document. Misuse of the device can result in a hazard. You can compromise the safety protection built into the device if the device is damaged in any way. If the device is damaged, return it to National Instruments (NI) for repair.

Do not substitute parts or modify the device except as described in this document. Use the device only with the chassis, devices, accessories, and cables specified in the installation instructions. You must have all covers and filler panels installed during operation of the device.

Do not operate the device in an explosive atmosphere or where there may be flammable gases or fumes. If you must operate the device in such an environment, it must be in a suitably rated enclosure.

If you need to clean the device, use a soft, nonmetallic brush. Make sure that the device is completely dry and free from contaminants before returning it to service.

ni.com/manuals.

Operate the device only at or below Pollution Degree 2. Pollution is foreign matter in a solid, liquid, or gaseous state that can reduce dielectric strength or surface resistivity. The following is a description of pollution degrees:

• Pollution Degree 1 means no pollution or only dry, nonconductive pollution occurs. The pollution has no influence.

• Pollution Degree 2 means that only nonconductive pollution occurs in most cases. Occasionally, however, a temporary conductivity caused by condensation must be expected.

NI PCI-5911 User Manual viii ni.com

About This Manual

• Pollution Degree 3 means that conductive pollution occurs, or dry, nonconductive pollution occurs that becomes conductive due to condensation.

You must insulate signal connections for the maximum voltage for which the device is rated. Do not exceed the maximum ratings for the device. Do not install wiring while the device is live with electrical signals. Do not remove or add connector blocks when power is connected to the system. Avoid contact between your body and the connector block signal when hot swapping devices. Remove power from signal lines before connecting them to or disconnecting them from the device.

Operate the device at or below the installation category hardware label. Measurement circuits are subjected to working voltages

marked on the

and transient stresses (overvoltage) from the circuit to which they are connected during measurement or test. Installation categories establish standard impulse withstand voltage levels that commonly occur in electrical distribution systems. The following is a description of installation categories:

• Installation Category I is for measurements performed on circuits not directly connected to the electrical distribution system referred to as MAINS

voltage. This category is for measurements of voltages from specially protected secondary circuits. Such voltage measurements include signal levels, special equipment, limited-energy parts of equipment, circuits powered by regulated low-voltage sources, and electronics.

• Installation Category II is for measurements performed on circuits directly connected to the electrical distribution system. This category refers to local-level electrical distribution, such as that provided by a standard wall outlet (for example, 115 AC voltage for U.S. or 230 AC voltage for Europe). Examples of Installation Category II are measurements performed on household appliances, portable tools, and similar devices.

• Installation Category III is for measurements performed in the building installation at the distribution level. This category refers to measurements on hard-wired equipment such as equipment in fixed installations, distribution boards, and circuit breakers. Other examples are wiring, including cables, bus bars, junction boxes, switches, socket

Installation categories, also referred to as measurement categories, are defined in electrical safety standard IEC 61010-1.

Working voltage is the highest rms value of an AC or DC voltage that can occur across any particular insulation.

MAINS is defined as a hazardous live electrical supply system that powers equipment. Suitably rated measuring circuits may be connected to the MAINS for measuring purposes.

About This Manual

outlets in the fixed installation, and stationary motors with permanent connections to fixed installations.

• Installation Category IV is for measurements performed at the primary electrical supply installation (<1,000 V). Examples include electricity meters and measurements on primary overcurrent protection devices and on ripple control units.

NI PCI-5911 User Manual x ni.com

Introduction

Thank you for buying an NI PCI-5911 digitizer, featuring the Flex ADC for variable speed and resolution. This chapter contains information on installing, connecting signals to, and acquiring data from the NI 5911

Installing the NI 5911

Installation involves the following main steps:

1. Install the NI-SCOPE driver software. You use this driver to write programs to control the NI 5911 in different application development environments (ADEs). Installing NI-SCOPE also allows you to interactively control the NI 5911 with the Scope Soft Front Panel.

2. Install the NI 5911.

For step-by-step instructions for installing both NI-SCOPE and the NI 5911, refer to the Where to Start with Your NI Digitizer document.

For multiple-device considerations, refer to the Operating Environment section of Appendix A, Specifications.

Connecting Signals

Figure 1-1 shows the front panel of the NI 5911. The front panel contains three connectors—a BNC connector, an SMB connector, and a 9-pin mini-circular DIN connector. Figure 1-2 shows the 9-pin mini-circular DIN connector.

The BNC connector is for attaching the analog input signal you want to measure. The BNC connector is analog input channel 0. To minimize noise, do not allow the shell of the BNC cable to touch or lie near the metal of the computer chassis. The SMB connector is used for external triggers and for generating a probe compensation signal. The SMB connector is labeled PFI 1. The DIN connector provides access to an additional external trigger line. The DIN connector can be used to access PFI 2.

Chapter 1 Introduction

Note The +5 V signal is fused at 1.1 A. However, NI recommends limiting the current

from this pin to 30 mA. The fuse is self-resetting.

CH 0

PFI 1

PFI 2 (DIN)

Figure 1-1. NI 5911 Connectors

NI PCI-5911 User Manual 1-2 ni.com

Chapter 1 Introduction

789

1 +5 V (Fused) 2GND 3 Reserved

Figure 1-2. 9-Pin Mini-Circular DIN Connector

4Reserved 5Reserved 6PFI 2

Acquiring Data with the NI 5911

You can acquire data either programmatically—by writing an application for the NI 5911—or interactively with the Scope Soft Front Panel.

Programmatically Controlling the NI 5911

To help you get started programming the NI 5911, NI-SCOPE includes examples that you can use or modify.

You can find examples for the following ADEs in these locations:

• LabVIEW—Go to

LabVIEW\Examples\Instr\niScopeExamples\

• LabWindows Windows 2000/NT—Go to

• LabWindows/CVI, C, and Visual Basic with Windows 98/95—Go to

vxipnp\win95\Niscope\Examples\c\.

Program Files\National Instruments\

™

/CVI™, C, and Visual Basic with

7 Reserved 8 Reserved 9 Reserved

vxipnp\winnt\Niscope\Examples\.

For information on using NI-SCOPE to programmatically control your digitizer, refer to the NI-SCOPE Software User Manual. Another resource is the NI-SCOPE Instrument Driver Quick Reference Guide, which contains abbreviated information on the most commonly used functions and LabVIEW VIs. For more detailed function reference help, refer to the

Chapter 1 Introduction

NI-SCOPE Function Reference Help, located at Start»Programs» National Instruments»NI-SCOPE. For more detailed VI help, use LabVIEW context-sensitive help (Help»Show Context Help) or the NI-SCOPE VI Reference Help, located at Start»Programs»National Instruments»NI-SCOPE.

Interactively Controlling the NI 5911 with the Scope Soft Front Panel

The Scope Soft Front Panel allows you to interactively control the NI 5911 as you would a desktop oscilloscope. To launch the Scope Soft Front Panel, select Start»Programs»National Instruments»NI-SCOPE» NI-SCOPE Soft Front Panel. Refer to the Scope Soft Front Panel Help for instructions on configuring the Scope Soft Front Panel for your specific application.

Note Press <F1> while the Scope Soft Front Panel is running to access the Scope Soft

Front Panel Help.

NI PCI-5911 User Manual 1-4 ni.com

Hardware Overview

This chapter includes an overview of the NI 5911, explains the operation of each functional unit making up the NI 5911, and describes the signal connections. Figure 2-1 shows a block diagram of the NI 5911.

Analog Input

Connector

Protect/

Calibration

Generator

Digital I/O Connector

Mux

AC/DC Coupling

PGIA

Noise

Shaper

Timing I/O,

Memory Control

Digital Signal

Processor

Figure 2-1. NI 5911 Block Diagram

A/D Converter

100 MHz, 8-Bit

Capture Memory

Reference Clock

Data

Differential Programmable Gain Input Amplifier (PGIA)

The analog input of the NI 5911 is equipped with a differential programmable gain input amplifier. The PGIA accurately interfaces to and scales the signal presented to the ADC regardless of source impedance, source amplitude, DC biasing, or common-mode noise voltages.

Differential Input

When measuring high dynamic range signals, ground noise is often a problem. The PGIA of the NI 5911 allows you to make noise-free signal measurements. The PGIA differential amplifier efficiently rejects any noise present on the ground signal. Internal to the PGIA, the signal

Chapter 2 Hardware Overview

presented at the negative input is subtracted from the signal presented at the positive input. As shown in Figure 2-2, this subtraction removes ground noise from the signal. The inner conductor of the BNC is V+. The outer shell is V–.

Input Signal

V+

V–

Ground Noise

Figure 2-2. Signal Noise-Free Measurements

PGIA

–

out

Grounding Considerations

The path for the positive signal has been optimized for speed and linearity. You should always apply signals to the positive input and ground to the negative input. Reversing the inputs results in higher distortion and lower bandwidth.

The negative input of the amplifier is grounded to PC ground through a 10 kΩ resistor. The PGIA is therefore referenced to ground, so it is not necessary to make any external ground connections. If the device you connect to the NI 5911 is already connected to ground, ground-loop noise voltages may be induced into your system. Notice that in most of these situations, the 10 kΩ resistance to PC ground is normally much higher than the cable impedances you use. As a result, most of the noise voltage occurs at the negative input of the PGIA where it is rejected, rather than in the positive input, where it would be amplified.

NI PCI-5911 User Manual 2-2 ni.com

Input Ranges

Chapter 2 Hardware Overview

To optimize the ADC resolution, you can select different gains for the PGIA so that you can scale your input signal to match the full input range of the converter. The NI 5911 PGIA offers seven input ranges, from ±0.1 V to ±10 V, as shown in Table 2-1.

Table 2-1. Input Ranges for the NI 5911

Range Input Protection Threshold

±10 V ±10 V

±5 V ±5 V

±2 V ±5 V

±1 V ±5 V

±0.5 V ±5 V

±0.2 V ±5 V

±0.1 V ±5 V

Note If you try to acquire a signal below the set input range, the sensitive front-end

components of the NI 5911 may become unstable and begin returning invalid data. To return the digitizer to a stable configuration, switch to the maximum input range setting and acquire an AC coupled or 0 V signal.

Input Impedance

The input stage of the NI 5911 requires a settling time that depends on which vertical range you are switching from and which vertical range you are switching to. However, allowing for a delay of 250 ms between configuring the input stage and starting the acquisition guarantees proper settling.

The input impedance of the NI 5911 PGIA is 1 MΩ between the positive and negative input, ±2% depending on input capacitance. The output impedance of the device connected to the NI 5911 and the input impedance of the NI 5911 form an impedance divider, which attenuates the input signal according to the following formula:

VsR

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

RsRin+

Chapter 2 Hardware Overview

Input Protection

where Vm is the measured voltage, Vs is the source voltage, Rs is the external source impedance, and R

is the input impedance.

If the device you are measuring has a very large output impedance, your measurements will be affected by this impedance divider. For example, if the device has 1 MΩ output impedance, your measured signal is one-half of the actual signal value.

Input Bias

The inputs of the PGIA typically draw an input bias current of 1 nA at 25 °C. Attaching a device with a very high source impedance can cause an offset voltage to be added to the signal measured, according to the formula R example, if the device you have attached to the NI 5911 has an output impedance of 10 kΩ, typically the offset voltage is 10 µV (10 kΩ × 1nA).

The NI 5911 features input-protection circuits that protect both the positive and negative analog inputs from damage from AC and DC signals up to ±42 V.

× 1 nA, where Rs is the external source impedance. For

If the voltage at one of these inputs exceeds a threshold voltage, V input clamps to V

and a resistance of 100 kΩ is inserted in the path to

, the

minimize input currents to a nonharmful level.

The protection voltage, V

is input range dependent, as shown in Table 2-1.

tr,

AC Coupling

When you measure a small AC signal on top of a large DC component, you can use AC coupling. AC coupling rejects any DC component in your signal before it enters into the PGIA. Activating AC coupling inserts a capacitor in series with the input impedance. You can select input coupling through software.

When changing the coupling on the digitizer, the input stage takes a finite amount of time to settle. When switching from AC to DC coupling, the settling time is approximately 0.5 ms. When switching from DC to AC coupling, the returned data is accurate several time constants after switching to AC. The NI 5911 has a time constant value of 68 ms. The equation 1 – e original signal has settled after time t. Generally, six time constants is enough time between switching to AC coupling and starting the acquisition

NI PCI-5911 User Manual 2-4 ni.com

–t/T

, where T is the time constant, gives the percentage that the

Chapter 2 Hardware Overview

to allow an 8-bit digitizer to acquire accurate data. However, the NI 5911 in flexible resolution mode is much more precise and thus requires a greater number of time constants of settling time to achieve the desired precision. Refer to Appendix A, Digitizer Basics, of the NI-SCOPE Software User Manual, for more information on input coupling.

Conventional and Flexible Resolution Modes

In conventional mode, the NI 5911 works as a conventional desktop oscilloscope, acquiring data at 100 MS/s with a vertical resolution of 8 bits. This mode is useful for displaying waveforms and for deriving waveform parameters such as slew rate, rise time, and settling time.

Flexible resolution mode differs from conventional mode in two ways: it has higher resolution (sampling rate dependent), and the signal bandwidth is limited to provide antialiasing protection. Flexible resolution mode is useful for spectral analysis, distortion analysis, and other measurements for which high resolution is crucial.

Conventional Mode

The ADC converts at a constant rate of 100 MS/s, but you can choose to store only a fraction of these samples into memory at a lower rate. This lower rate allows you to store waveforms using fewer data points and decreases the burden of storing, analyzing, and displaying the waveforms. If you need faster sampling rates, you can use Random Interleaved Sampling (RIS) to effectively increase the sampling rate to 1 GS/s for repetitive waveforms.

In conventional mode, all signals up to 100 MHz are passed to the ADC. You must ensure that your signal is band-limited to prevent aliasing. Aliasing and other sampling terms are described more thoroughly in the NI-SCOPE Software User Manual.

Sampling Methods

Two sampling methods are available in conventional mode: real-time sampling and random interleaved sampling (RIS). Using real-time

sampling, you can acquire data at a rate of 100/n MS/s, where n is a number from 1 to 2 extend the sampling rate above 100 MS/s. In RIS mode, you can sample at rates of 100 × n MS/s, where n is a number from 2 to 10.

. RIS sampling can be used on repetitive signals to effectively

Chapter 2 Hardware Overview

Flexible Resolution Mode

Table 2-2 shows the relationship between the available sampling rates, resolution, and the corresponding bandwidth for flexible resolution mode.

Table 2-2. Available Sampling Rates and Corresponding Bandwidth

Sampling Rate Resolution Bandwidth

12.5 MS/s 11 bits 3.75 MHz

2.5 MS/s 15.5 bits 1 MHz

500 kS/s 18 bits 200 kHz

200 kS/s 18.5 bits 80 kHz

100 kS/s 19 bits 40 kHz

in Flexible Resolution Mode

5 MS/s 14 bits 2 MHz

1 MS/s 17.5 bits 400 kHz

50 kS/s 19.5 bits 20 kHz

20 kS/s 20.5 bits 8 kHz

10 kS/s 21 bits 4 kHz

Like any other type of converter that uses noise shaping to enhance resolution, the frequency response of the converter is only flat to its maximum useful bandwidth. The NI 5911 has a bandwidth of 4 MHz. Beyond this frequency, there is a span where the converter acts resonant and where a signal is amplified before being converted. These signals are attenuated in the subsequent digital filter to prevent aliasing. However, if the applied signal contains major signal components in this frequency range, such as harmonics or noise, the converter may overload and signal data will be invalid. In this case, you receive an overload warning. You must then either select a higher input range or attenuate the signal.

How Flexible Resolution Works

The ADC can be sourced through a noise shaping circuit that moves quantization noise on the output of the ADC from lower frequencies to higher frequencies. A digital lowpass filter applied to the data removes all but a fraction of the original shaped quantization noise. The signal is then resampled to a lower sampling frequency and a higher resolution. Flexible resolution provides antialiasing protection due to the digital lowpass filter.

NI PCI-5911 User Manual 2-6 ni.com

Calibration

The NI 5911 can be calibrated for high accuracy and resolution because of an advanced calibration scheme. There are two different types of calibration: internal, or self-calibration, and external calibration. A third option, internal restore, restores factory settings and should be used only in the event of a self-calibration failure.

Self-calibration is performed using a software command that compensates for drifts caused by environmental temperature changes. You can self-calibrate the NI 5911 without any external equipment connected. External calibration requires you to connect an external precision voltage reference to the device. External calibration recalibrates the device when the specified calibration interval has expired. Refer to Appendix A,

Specifications, for the calibration interval.

Self-Calibrating the NI 5911

You can self-calibrate the NI 5911 with a software function or a LabVIEW VI. Refer to Chapter 3, Common Functions and Examples, of the NI-SCOPE Software User Manual, for step-by-step instructions for self-calibrating the NI 5911.

Chapter 2 Hardware Overview

When Self-Calibration Is Needed

To provide the maximum accuracy independent of temperature changes, the NI 5911 contains a heater that stabilizes the temperature of the most sensitive circuitries on the board. However, the heater can accommodate for temperature changes over a fixed range of ±5 °C. When temperatures exceed this range, the heater cannot stabilize the temperature, and signal data becomes inaccurate. When the temperature range has been exceeded, you receive a warning, and you must perform an internal calibration.

What Self-Calibration Does

Self-calibration performs the following operations:

• The heater is set to regulate over a range of temperatures centered at the current environmental temperature. The circuit components require time to stabilize at the new temperature. This temperature stabilization accounts for the majority of the calibration time. Refer to the

Calibration section of Appendix A, Specifications, for more

information.

• Gain and offset are calibrated for each individual input range.

Chapter 2 Hardware Overview

Caution Do not apply high-amplitude or high-frequency signals to the NI 5911 during

self-calibration. For optimal calibration performance, disconnect the input signal from the NI 5911.

• The linearity of the ADC is calibrated using an internal sine wave generator as reference.

• The time-to-digital converter used for RIS measurements is calibrated.

Why Warnings Occur During Acquisition

The NI 5911 uses a heater circuit to maintain constant temperature on the critical circuitry used in flexible resolution mode. If this circuit cannot maintain the temperature within specification, a warning is generated. This warning indicates that the temperature of the ADC is out of range and should be recalibrated with a self-calibration. During acquisition in flexible resolution mode, a warning is generated if the input to the ADC goes out of range for the converter. The fact that this condition has occurred may not be obvious from inspecting the data because of the digital filtering that takes place on the acquired data. Therefore, a warning occurs to notify you that the data includes some samples that were out of the range of the converter and may be inaccurate.

External Calibration

External calibration calibrates the internal reference on the NI 5911. The NI 5911 is already calibrated when it is shipped from the factory. Periodically, the NI 5911 needs external calibration to remain within the specified accuracy. For more information on calibration, contact NI, or visit

ni.com/calibration. For actual intervals and accuracy, refer to

the Calibration section of Appendix A, Specifications.

Triggering and Arming

There are several triggering methods for the NI 5911. The trigger can be an analog level that is compared to the input or any of several digital inputs. You also can call a software function to trigger the digitizer. Figure 2-3 shows the different trigger sources. When you use a digital signal, that signal must be at a high TTL level for at least 40 ns before any triggers are accepted.

Note The NI 5911 does not support delayed triggering.

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Chapter 2 Hardware Overview

Analog

Input

Gain

ATC_OUT

RTSI<0..6>

PFI 1, PFI 2

High

Level

Low

Level

a. Analog Trigger Circuit

Software

b. Trigger and Arm Sources

+ COMP

COMP –

Figure 2-3. Trigger Sources

Analog Trigger

Circuit

Trigger

Arm

ATC_OUT

Analog Trigger Circuit

The analog trigger on the NI 5911 operates by comparing the current analog input to an onboard threshold voltage. This threshold voltage is the trigger value, and can be set within the current input range in 170 steps. Therefore, for a ±10 V input range, the trigger can be set in increments of 20 V/170 = 118 mV. A hysteresis value may also be associated with the trigger that can be set in the same size increments. The hysteresis value creates a trigger window the signal must pass through before the trigger is accepted. You can generate triggers on a rising or falling edge condition. For more information on triggering, refer to Chapter 3, Common Functions and Examples, of the NI-SCOPE Software User Manual.

Chapter 2 Hardware Overview

Trigger Holdoff

Note Time to acquire posttrigger samples is calculated by the following formula:

(posttrigger samples)/(sample rate).

Memory

Trigger holdoff is the minimum length of time (in seconds) from an accepted trigger to the start of the next record. In other words, when a trigger is accepted, the trigger counter is loaded with the desired holdoff time. After completing its current record, the digitizer records no data and accepts no triggers until the holdoff counter runs out. When the counter runs out, the next record begins and a trigger may be accepted. Setting a holdoff time shorter than posttrigger acquisition time has no effect, as triggers are always rejected during an acquisition.

Trigger holdoff is provided in hardware using a 32-bit counter clocked by a 25 MHz internal timebase. With this configuration, you can select a hardware holdoff value of 5 µs to 171.79 s in increments of 40 ns. For more information on trigger holdoff, refer to Chapter 3, Common Functions and Examples, of the NI-SCOPE Software User Manual.

The NI 5911 allocates at least 4 kB of onboard memory for each record in a single multi-record acquisition. Samples are stored in this buffer before transfer to the host computer. Thus the minimum size for a buffer in the onboard memory is approximately 4,000 8-bit conventional mode samples or 1,000 32-bit flexible resolution mode samples. Software allows you to specify buffers of less than these minimum buffer sizes because only the specified number of points is transferred from onboard memory into the memory of the host computer.

The total number of samples that can be stored depends on the size of the acquisition memory module installed on the NI 5911 and the size of each acquired sample. The maximum number of records in a single multi-record acquisition is equal to the size of the memory module divided by 4 kB.

Triggering and Memory Usage

During the acquisition, samples are stored in a circular buffer that is continually rewritten until a trigger is received. After the trigger is received, the NI 5911 continues to acquire posttrigger samples if you have specified a posttrigger sample count. The acquired samples are placed into onboard memory. The number of posttrigger or pretrigger samples is only limited by the amount of onboard memory.

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Multi-Record Acquisitions

After the trigger has been received and the posttrigger samples have been stored, the NI 5911 can be configured to begin another acquisition that is stored in another onboard memory record. This operation is a multi-record acquisition. To perform multi-record acquisitions, configure the NI 5911 to the number of records you want to acquire before starting the acquisition. The NI 5911 acquires an additional record each time a trigger is accepted until all the requested records are stored in memory. You may acquire up to 1,024 records if your NI 5911 is equipped with 4 MB of onboard memory, or 4,096 records with 16 MB of onboard memory. Software intervention after the initial setup is not required.

Multi-record acquisitions can quickly acquire numerous triggered waveforms because they allow hardware rearming of the digitizer before the data is fetched. Therefore the dead time, or the time when the digitizer is not ready for a trigger, is extremely small.

For more information on multi-record acquisitions and dead time, refer to Chapter 5, Tasks and Examples, of the NI-SCOPE Software User Manual.

Chapter 2 Hardware Overview

RTSI Bus and Clock PFI

The Real-Time System Integration (RTSI) bus allows NI digitizers to synchronize timing and triggering on multiple devices. The RTSI bus has seven bidirectional trigger lines and one bidirectional clock signal.

You can program any of the seven trigger lines to provide or accept a synchronous trigger signal. You can also use any of the RTSI trigger lines to provide a synchronization pulse from a master device if you are synchronizing multiple NI 5911 devices.

You can use the RTSI bus clock line to provide or accept a 10 MHz reference clock to synchronize multiple NI 5911 devices.

PFI Lines

The NI 5911 has two digital lines that can accept a trigger, accept or generate a reference clock, or output a 1 kHz square wave. The function of each PFI line is independent. However, only one trigger source can be accepted during acquisition.

Chapter 2 Hardware Overview

Synchronization

PFI Lines as Inputs

You can select PFI 1 or PFI 2 as inputs for a trigger or a reference clock. Refer to the Synchronization section for more information about the use of reference clocks in the NI 5911.

PFI Lines as Outputs

You can select PFI 1 or PFI 2 to output several digital signals.

Reference Clock is a 10 MHz clock that is synchronous to the 100 MHz sample clock on the NI 5911. You can use the Reference Clock to synchronize to another NI 5911 configured as a slave device or to other equipment that can accept a 10 MHz reference.

Frequency Output is a 1 kHz digital pulse train signal with a 50% duty cycle. The most common application of Frequency Output for the NI 5911 is to provide a signal for compensating a passive probe.

The NI 5911 uses a digital phase-locked loop to synchronize the 100 MHz sample clock to a 10 MHz reference. This reference frequency can be supplied by an internal crystal oscillator or through an external frequency input through the RTSI bus clock line or a PFI input.

The NI 5911 can also output its 10 MHz reference on the RTSI bus clock line or a PFI line so that additional NI 5911 devices or other equipment can be synchronized to the same reference.

While the reference clock input is sufficient to synchronize the 100 MHz sample clocks, it is also necessary to synchronize clock dividers on each NI 5911 so that internal clock divisors are synchronized on each device. These lower frequencies are important because they are used to determine trigger times and sample position.

To synchronize the NI 5911 clock dividers, you must connect the digitizers with an RTSI bus cable. One of the RTSI bus triggers must be designated as a synchronization line. This line is an output from the master device and an input on the slave device. To synchronize the digitizers, a single pulse is sent from the master NI 5911 to the slaves. This pulse supplies the slave devices with a reference time to clear their clock dividers. Hardware arming cannot be used during an acquisition using multiple devices.

To synchronize the triggers of multiple NI 5911 devices, one digitizer must receive a trigger as described in the Triggering and Arming section and then

NI PCI-5911 User Manual 2-12 ni.com

Chapter 2 Hardware Overview

route that trigger over the RTSI bus to trigger the other digitizer(s). However, the trigger that is routed to the other digitizer(s) is sent synchronously to an internal 25 MHz clock. For more information about synchronization, refer to the NI-SCOPE Software User Manual.

Specifications

This appendix lists the specifications of the NI 5911. These specifications are typical at 25 °C unless otherwise stated.

Acquisition System

Bandwidth .............................................. 100 MHz maximum;

Number of channels ............................... 1

Number of flexible resolution ADC....... 1

Max RIS sample rate.............................. 1 GS/s

Max real-time sample rate...................... 100 MS/s

refer to Table 2-2, Available

Sampling Rates and Corresponding Bandwidth in Flexible Resolution Mode

Resolution

Sample Rate Mode Effective Resolution

100/n* MS/s Conventional 8 bits

12.5 MS/s Flexible Resolution 11 bits

5 MS/s Flexible Resolution 14 bits

2.5 MS/s Flexible Resolution 15.5 bits

1 MS/s Flexible Resolution 17.5 bits

500 kS/s Flexible Resolution 18 bits

200 kS/s Flexible Resolution 18.5 bits

100 kS/s Flexible Resolution 19 bits

50 kS/s Flexible Resolution 19.5 bits

Appendix A Specifications

Sample Rate Mode Effective Resolution

20 kS/s Flexible Resolution 20.5 bits

10 kS/s Flexible Resolution 21 bits

* 1 ≤ n ≤ 224 in conventional mode

Sample onboard memory........................4 MB or 16 MB

Memory Sample Depth

Sampling

Frequency

Mode

Sample Depth

(4 MB)

Sample Depth

(16 MB)

100/n* MS/s Conventional 4 MS 16 MS

12.5 MS/s Flexible

1 MS 4 MS

Resolution

5 MS/s Flexible

1 MS 4 MS

Resolution

2.5 MS/s Flexible

1 MS 4 MS

Resolution

1 MS/s Flexible

1 MS 4 MS

Resolution

500 kS/s Flexible

1 MS 4 MS

Resolution

200 kS/s Flexible

1 MS 4 MS

Resolution

100 kS/s Flexible

1 MS 4 MS

Resolution

50 kS/s Flexible

1 MS 4 MS

Resolution

20 kS/s Flexible

1 MS 4 MS

Resolution

10 kS/s Flexible

1 MS 4 MS

Resolution

* 1 ≤ n ≤ 2

NI PCI-5911 User Manual A-2 ni.com

in conventional mode

Vertical Sensitivity (Input Ranges)

Input Range Noise Referred to Input

Appendix A Specifications

Acquisition Characteristics

Accuracy

DC gain accuracy ................................... ±0.05% signal ±0.0001% fs

DC offset accuracy................................. ±0.1 mV ±0.01% fs

Input coupling ........................................DC and AC, software selectable

±10 V –174 dBfs/

±5 V –168 dBfs/

±2 V –160 dBfs/

±1 V –154 dBfs/

±0.5 V –148 dBfs/

±0.2 V –140 dBfs/

±0.1 V –128 dBfs/

for all input ranges at 1 MS/s in flexible resolution mode

AC coupling cut-off frequency

(–3 dB) ................................................... 2.5 Hz ±0.5 Hz

Input impedance..................................... 1 MΩ ±2%

Max measurable input voltage ............... ±10 V (DC + peak AC)

Input protection ...................................... ±42 VDC (DC + peak AC)

Input bias current ................................... ±1 nA, typical at 25 °C

Common-Mode Characteristics

Impedance to chassis ground ................. 10 kΩ

Common-mode rejection ratio ............... CMRR > –70 dB, (F

< 1 kHz)

Appendix A Specifications

Filtering

Sampling Frequency Filter Mode Bandwidth Ripple Alias Attenuation

100/n* MS/s Conventional 100 MHz ±3 dB N/A

12.5 MS/s Flexible Resolution

5 MS/s Flexible

Resolution

2.5 MS/s Flexible Resolution

1 MS/s Flexible

Resolution

500 kS/s Flexible

Resolution

200 kS/s Flexible

Resolution

100 kS/s Flexible

Resolution

50 kS/s Flexible

Resolution

20 kS/s Flexible

Resolution

10 kS/s Flexible

Resolution

3.75 MHz ±0.2 dB –60 dB

2 MHz ±0.1 dB –70 dB

1 MHz ±0.05 dB –80 dB

400 kHz ±0.005 dB –80 dB

200 kHz ±0.005 dB –80 dB

80 kHz ±0.005 dB –80 dB

40 kHz ±0.005 dB –80 dB

20 kHz ±0.005 dB –80 dB

8 kHz ±0.005 dB –80 dB

4 kHz ±0.005 dB –80 dB

* 1 ≤ n ≤ 224 in conventional mode

Dynamic Range

Noise (excluding input-referred noise)

Sampling Frequency Bandwidth Noise Density Tota l Noi s e

100/n* MS/s

12.5 MS/s 3.75 MHz

5 MS/s 2 MHz

2.5 MS/s 1 MHz

NI PCI-5911 User Manual A-4 ni.com

100 MHz

–120 dBfs/

–135 dBfs/

–143 dBfs/

–152 dBfs/

–43 dBfs

–64 dBfs

–83 dBfs

–91 dBfs

Appendix A Specifications

Sampling Frequency Bandwidth Noise Density Tota l Noi s e

1 MS/s 400 kHz

500 kS/s 200 kHz

200 kS/s 80 kHz

100 kS/s 40 kHz

50 kS/s 20 kHz

20 kS/s 8 kHz

10 kS/s 4 kHz

* 1 ≤ n ≤ 224 in conventional mode

–160 dBfs/

Distortion

Sampling

Frequency

100 MS/s 50 dBfs 50 dBfs N/A

12.5 MS/s 65 dBfs 85 dBfs 125 dBfs

5 MS/s 70 dBfs 90 dBfs 130 dBfs

2.5 MS/s 75 dBfs 95 dBfs 135 dBfs

1 MS/s 85 dBfs 105 dBfs 145 dBfs

SFDR for Input

0 dBfs

SFDR for Input

–20 dBfs

SFDR for Input

–60 dBfs (typical)

–104 dBfs

–107 dBfs

–111 dBfs

–114 dBfs

–117 dBfs

–121 dBfs

–124 dBfs

500 kS/s 90 dBfs 110 dBfs 150 dBv

200 kS/s 100 dBfs 110 dBfs 160 dBfs

100 kS/s 100 dBfs 110 dBfs 160 dBfs

50 kS/s 100 dBfs 110 dBfs 160 dBfs

20 kS/s 100 dBfs 110 dBfs 160 dBfs

10 kS/s 100 dBfs 110 dBfs 160 dBfs

Timebase System

Reference clock...................................... 10 MHz

Clock accuracy (as master) .................... 10 MHz ±50 ppm

Clock input tolerance (as slave) ............. 10 MHz ±100 ppm

Appendix A Specifications

Triggering Systems

Clock jitter ..............................................<75 pS

, independent of

rms

reference clock source

Clock compatibility ................................TTL for both input and output

Sampling clock frequencies

Conventional mode....................... 100/n MHz, where 1 ≤ n ≤2

Flexible resolution mode .................12.5 MHz, 5 MHz, 2.5 MHz,

1 MHz, 500 kHz, 200 kHz, 100 kHz, 50 kHz, 20 kHz, 10 kHz

Reference clock sources .........................PFI lines, RTSI clock, or onboard

Modes .....................................................Edge, hysteresis, window, digital

Source .....................................................CH0, RTSI<0..6>, PFI 1, 2

Slope .......................................................Rising/falling

Hysteresis................................................Full-scale voltage/n, where n is

between 1 and 170

Coupling .................................................AC/DC

Pretrigger depth ......................................Up to 4 MS or 16 MS, depending

on memory option purchased and sampling mode

Posttrigger depth.....................................Up to 4 MS or 16 MS, depending

on memory option purchased and sampling mode

Holdoff time ...........................................5 µs to 171.79 s in increments

of 40 ns

Trigger resolution ...................................170 steps in full-scale voltage

range

NI PCI-5911 User Manual A-6 ni.com

Sampling Methods

Random interleaved sampling................ 1 GS/s down to 200 MS/s

Real-time sampling ................................ Up to 100 MS/s sample rate for

Power Requirements

+5 VDC .................................................. 4 A

+12 VDC................................................100 mA

–12 VDC ................................................ 100 mA

Physical

Dimensions............................................. 33.8 by 9.9 cm (13.3 by 3.9 in.)

I/O connectors

Appendix A Specifications

effective sample rate, repetitive signals only

transient and repetitive signals

Analog input CH0........................... BNC female

Digital triggers ................................ SMB female, 9-pin mini DIN

Operating Environment

Note Multiple NI 5911 devices in the same computer may raise operating temperatures

beyond specification and give rise to imprecise data. NI strongly recommends leaving an empty PCI slot between multiple NI 5911 devices or adding a fan.

Ambient temperature.............................. 5 °C to 40 °C

Relative humidity................................... 10% to 90%, noncondensing

Storage Environment

Ambient temperature.............................. –20 °C to 65 °C

Appendix A Specifications

Calibration

Safety

Self-calibration (internal calibration) .....Self-calibration is done using a

software command. The calibration involves gain, offset and linearity correction for all input ranges and input modes.

Interval.............................................1 week, or any time temperature

changes beyond ±5 °C. Hardware detects temperature variations beyond calibration limits, which can also be queried by software.

External calibration.................................Internal reference requires

recalibration

Interval.............................................1 year

Warm-up time.........................................15 minutes

This product is designed to meet the requirements of the following standards of safety for electrical equipment for measurement, control and laboratory use:

• IEC 61010-1, EN 61010-1

• UL 3111-1, UL 61010B-1

• CAN/CSA C22.2 No. 1010.1

Note For UL and other safety certifications, refer to the product label or to ni.com.

Electromagnetic Compatibility

Emissions................................................EN 55011 Class A at 10 m

FCC Part 15A above 1 GHz

Immunity ................................................EN 61326:1997 + A2:2001,

Table 1

EMC/EMI ...............................................CE, C-Tick and FCC Part 15

(Class A) Compliant

Note For EMC compliance, operate this device with shielded cabling.

NI PCI-5911 User Manual A-8 ni.com

CE Compliance

Note Refer to the Declaration of Conformity (DoC) for this product for any additional

regulatory compliance information. To obtain the DoC for this product, click Declarations of Conformity Information at

Appendix A Specifications

This product meets the essential requirements of applicable European Directives, as amended for CE Marking, as follows:

• Low-Voltage Directive (safety):73/23/EEC

• Electromagnetic Compatibility Directive (EMC):89/336/EEC

ni.com/hardref.nsf/.

Technical Support and Professional Services

Visit the following sections of the National Instruments Web site at

ni.com for technical support and professional services:

• Support—Online technical support resources include the following:

– Self-Help Resources—For immediate answers and solutions,

visit our extensive library of technical support resources available in English, Japanese, and Spanish at resources are available for most products at no cost to registered users and include software drivers and updates, a KnowledgeBase, product manuals, step-by-step troubleshooting wizards, conformity documentation, example code, tutorials and application notes, instrument drivers, discussion forums, a measurement glossary, and so on.

– Assisted Support Options—Contact NI engineers and other

measurement and automation professionals by visiting

support

connects you to the experts by phone, discussion forum, or email.

• Training—Visit

interactive CDs. You also can register for instructor-led, hands-on courses at locations around the world.

• System Integration—If you have time constraints, limited in-house

technical resources, or other project challenges, NI Alliance Program members can help. To learn more, call your local NI office or visit

ni.com/alliance.

• Declaration of Conformity (DoC)—A DoC is our claim of

compliance with the Council of the European Communities using the manufacturer’s declaration of conformity. This system affords the user protection for electronic compatibility (EMC) and product safety. You can obtain the DoC for your product by visiting

hardref.nsf

• Calibration Certificate—If your product supports calibration, you

can obtain the calibration certificate for your product at

calibration

. Our online system helps you define your question and

ni.com/custed for self-paced tutorials, videos, and

ni.com/support. These

ni.com/

Appendix B Technical Support and Professional Services

If you searched ni.com and could not find the answers you need, contact your local office or NI corporate headquarters. Phone numbers for our worldwide offices are listed at the front of this manual. You also can visit the Worldwide Offices section of office Web sites, which provide up-to-date contact information, support phone numbers, email addresses, and current events.

ni.com/niglobal to access the branch

NI PCI-5911 User Manual B-2 ni.com

Glossary

Symbol Prefix Value

ppico10

nnano10

µ micro 10

m milli 10

k kilo 10

Mmega10

Ggiga10

Symbols

% percent

+ positive of, or plus

–12

–9

–6

–3

– negative of, or minus

/per

°degree

± plus or minus

Ω ohm

A amperes

A/D analog to digital

AC alternating current

Glossary

AC coupled the passing of a signal through a filter network that removes the

DC component of the signal

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

circuit, that converts an analog voltage to a digital number

ADC resolution the resolution of the ADC, which is measured in bits. An ADC with16 bits

has a higher resolution, and thus a higher degree of accuracy, than a 12-bit ADC.

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

attenuate to reduce in magnitude

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

buffer temporary storage for acquired or generated data (software)

bus the group of conductors that interconnect individual circuitry in a computer.

Typically, a bus is the expansion vehicle to which I/O or other devices are connected. Examples of PC buses are the PCI and ISA bus.

CCelsius

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

digital signal

NI PCI-5911 User Manual G-2 ni.com

Glossary

clock hardware component that controls timing for reading from or writing to

groups

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)

counter/timer a circuit that counts external pulses or clock pulses (timing)

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

dB decibel—the unit for expressing a logarithmic measure of the ratio of

two signal levels: dB = 20log10 V1/V2, for signals in volts

DC direct current

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.

device A plug-in data acquisition device, card, or pad that can contain multiple

channels and conversion devices. Plug-in devices, PCMCIA cards, and devices such as the DAQPad-1200, which connects to your computer parallel port, are all examples of DAQ devices. SCXI modules are distinct from devices, with the exception of the SCXI-1200, which is a hybrid. The NI 5911 is an example of a device.

differential input an analog input consisting of two terminals, both of which are isolated from

computer ground, whose difference is measured

double insulated a device that contains the necessary insulating structures to provide electric

shock protection without the requirement of a safety ground connection

drivers software that controls a specific hardware instrument

Glossary

EEPROM electrically erasable programmable read-only memory—ROM that can be

erased with an electrical signal and reprogrammed

equivalent time sampling

event the condition or state of an analog or digital signal

any method used to sample signals in such a way that the apparent sampling rate is higher than the real sampling rate

filtering a type of signal conditioning that allows you to filter unwanted signals from

the signal you are trying to measure

fs full-scale—total voltage in the input range. A ±10 V input range is 20 V fs

gain the factor by which a signal is amplified, sometimes expressed in decibels

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

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

harmonics multiples of the fundamental frequency of a signal

Hz hertz—per second, as in cycles per second or samples per second

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

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

inductance the relationship of induced voltage to current

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

NI PCI-5911 User Manual G-4 ni.com

Glossary

input impedance the measured resistance and capacitance between the input terminals of a

circuit

instrument driver a set of high-level software functions that controls a specific plug-in DAQ

board. Instrument drivers are available in several forms, ranging from a function callable language to a virtual instrument (VI) in LabVIEW.

interrupt a computer signal indicating that the CPU should suspend its current task

to service a designated activity

interrupt level the relative priority at which a device can interrupt

ISA industry standard architecture

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

measure such as volts, hertz, and meters

kS 1,000 samples

LabVIEW laboratory virtual instrument engineering workbench—a graphical

programming ADE developed by National Instruments

LSB least significant bit

m meters

MB megabytes of memory

memory buffer See buffer.

MS million samples

MSB most significant bit

Glossary

noise an undesirable electrical signal—noise 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. Noise corrupts signals you are trying to send or receive.

Nyquist frequency a frequency that is one-half the sampling rate. See also Nyquist Sampling

Theorem.

Nyquist Sampling Theorem

the theorem states that if a continuous bandwidth-limited analog signal contains no frequency components higher than half the frequency at which it is sampled, then the original signal can be recovered without distortion.

Ohm’s Law (R = V/I)—the relationship of voltage to current in a resistance

overrange a segment of the input range of an instrument outside of the normal

measuring range. Measurements can still be made, usually with a degradation in specifications.

oversampling sampling at a rate greater than the Nyquist frequency

passband the frequency range that a filter passes without attenuation

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 workstations and offers a theoretical maximum transfer rate of 132 Mbytes/s

peak value the absolute maximum or minimum amplitude of a signal (AC + DC)

posttriggering the technique to acquire a programmed number of samples after trigger

conditions are met

NI PCI-5911 User Manual G-6 ni.com

Glossary

pretriggering the technique used on a device to keep a buffer filled with data, so that when

the trigger conditions are met, the sample includes the data leading up to the trigger condition

PXI PCI eXtensions for Instrumentation. PXI is an open specification that

builds off the CompactPCI specification by adding instrumentation-specific features.

Rresistor

RAM random-access memory

real-time sampling sampling that occurs immediately

random interleaved sampling (RIS)

resolution the smallest signal increment that can be detected by a measurement

rms root mean square—a measure of signal amplitude; the square root of the

ROM read-only memory

RTSI bus real-time system integration bus—the National Instruments timing bus that

method of increasing the sample rate by repetitively sampling a repeated waveform

system. Resolution can be expressed in bits or in digits. The number of bits in a system is roughly equal to 3.3 times the number of digits.

average value of the square of the instantaneous signal amplitude

connects devices directly, by means of connectors on top of the boards, for precise synchronization of functions

s seconds

S samples

S/s samples per second—used to express the rate at which an instrument

samples an analog signal. 100 MS/s would equal 100 million samples each second.

Glossary

sense in four-wire resistance the sense measures the voltage across the resistor

being excited by the excitation current

settling time the amount of time required for a voltage to reach its final value within

specified limits

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

temperature coefficient

thermal drift measurements that change as the temperature varies

thermal EMFs thermal electromotive forces—voltages generated at the junctions of

thermoelectric potentials

transfer rate the rate, measured in bytes/s, at which data is moved from source to

trigger any event that causes or starts some form of data capture

the percentage that a measurement will vary according to temperature. See also thermal drift.

dissimilar metals that are functions of temperature. Also called thermoelectric potentials.

See thermal EMFs.

destination after software initialization and set up operations; the maximum rate at which the hardware can operate

undersampling sampling at a rate lower than the Nyquist frequency—can cause aliasing

update rate the number of output updates per second

NI PCI-5911 User Manual G-8 ni.com

Vvolts

VAC volts alternating current

VDC volts direct current

Glossary

error

voltage error

VI virtual instrument—(1) a combination of hardware and/or software

elements, typically used with a PC, that has the functionality of a classic stand-alone instrument (2) a LabVIEW software module (VI), which consists of a front panel user interface and a block diagram program

rms

volts, root mean square value

waveform shape the shape the magnitude of a signal creates over time

working voltage the highest voltage that should be applied to a product in normal use,

normally well under the breakdown voltage for safety margin

Index

AC coupling, 2-4 accuracy characteristics, A-3 acquisition

multiple record, 2-11 Scope Soft Front Panel, 1-4

acquisition characteristics specifications

accuracy, A-3 common-mode characteristics, A-3 distortion, A-5 dynamic range, A-4

filtering, A-4 acquisition modes specifications, A-7 acquisition system specifications, A-1 analog trigger circuit, 2-9 arming. See triggering and arming

bias, input, 2-4 block diagram of NI 5911, 2-1 BNC connector, 1-1

calibration

errors occurring during acquisition, 2-8

external calibration, 2-8

internal calibration, 2-7

specifications, A-8 calibration certificate, B-1 clock lines, 2-12 common-mode characteristics, A-3 connectors

BNC connector, 1-1

DIN connector, 1-1

location on front panel (figure), 1-2

SMB connector, 1-1 contacting National Instruments, B-2 conventions used in the manual, vii customer

education, B-1

professional services, B-1

technical support, B-1

dead time, in multiple record acquisition, 2-11 Declaration of Conformity, B-1 diagnostic resources, B-1 differential input

grounding considerations, 2-2

noise-free signal measurement (figure), 2-2 differential programmable gain input amplifier

(PGIA)

AC coupling, 2-4

differential input, 2-1

input bias, 2-4

input impedance, 2-3

input protection, 2-4

input ranges, 2-3

noise-free signal measurement (figure), 2-2 DIN connector, 1-1 distortion specifications, A-5 documentation

conventions used in manual, vii

online library, B-1

National Instruments NI PCI-5911 User Manual

Specifications and Main Features

Frequently Asked Questions

User Manual

NI PCI-5911 User Manual

Support

Worldwide Technical Support and Product Information

National Instruments Corporate Headquarters

Worldwide Offices

Important Information

Warranty

Copyright

Trademarks

Patents

WARNING REGARDING USE OF NATIONAL INSTRUMENTS PRODUCTS

Compliance

Contents

About This Manual

Conventions

Related Documentation

Safety Information

Installing the NI 5911

Connecting Signals

Figure 1-1. NI 5911 Connectors

Figure 1-2. 9-Pin Mini-Circular DIN Connector

Acquiring Data with the NI 5911

Programmatically Controlling the NI 5911

Interactively Controlling the NI 5911 with the Scope Soft Front Panel

Figure 2-1. NI 5911 Block Diagram

Differential Programmable Gain Input Amplifier (PGIA)

Differential Input

Figure 2-2. Signal Noise-Free Measurements

Grounding Considerations

Input Ranges

Table 2-1. Input Ranges for the NI 5911

Input Impedance

Input Protection

Input Bias

AC Coupling

Conventional and Flexible Resolution Modes

Conventional Mode

Sampling Methods

Flexible Resolution Mode

How Flexible Resolution Works

Calibration

Self-Calibrating the NI 5911

When Self-Calibration Is Needed

What Self-Calibration Does

Why Warnings Occur During Acquisition

External Calibration

Triggering and Arming

Figure 2-3. Trigger Sources

Analog Trigger Circuit

Trigger Holdoff

Memory

Triggering and Memory Usage

Multi-Record Acquisitions

RTSI Bus and Clock PFI

PFI Lines

Synchronization

PFI Lines as Inputs

PFI Lines as Outputs

Glossary

Symbols

Index