National Instruments Graphics Tablet NI 5911 User Manual

Computer-Based  
Instruments  
NI 5911 User Manual  
High-Speed Digitizer with FLEX ADC™  
NI 5911 User Manual  
June 2001 Edition  
Part Number 322150D-01  
 
 
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.  
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accuracy. In the event that technical or typographical errors exist, National Instruments reserves the right to make changes to subsequent  
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Instruments Corporation.  
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Product and company names mentioned herein are trademarks or trade names of their respective companies.  
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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). Depending on where it is operated, this 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. By  
examining the product you purchased, you can determine the FCC Class and therefore which of the two FCC/DOC Warnings  
apply in the following sections. (Some products may not be labeled at all for FCC; if so, the reader should then assume these are  
Class A devices.)  
FCC Class A products only display a simple warning statement of one paragraph in length regarding interference and undesired  
operation. Most of our products are FCC Class A. The FCC rules have restrictions regarding the locations where FCC Class A  
products can be operated.  
FCC Class B products display either a FCC ID code, starting with the letters EXN,  
or the FCC Class B compliance mark that appears as shown here on the right.  
Consult the FCC web site http://www.fcc.govfor more information.  
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 Mark 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 National Instruments could void the users 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 will be required to correct  
the interference at his own expense.  
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.  
Class B  
Federal Communications Commission  
This equipment has been tested and found to comply with the limits for a Class B digital device, pursuant to part 15 of the  
FCC Rules. These limits are designed to provide reasonable protection against harmful interference in a residential installation.  
This equipment generates, uses and can radiate radio frequency energy and, if not installed and used in accordance with the  
instructions, may cause harmful interference to radio communications. However, there is no guarantee that interference will not  
occur in a particular installation. If this equipment does cause harmful interference to radio or television reception, which can  
be determined by turning the equipment off and on, the user is encouraged to try to correct the interference by one or more of  
the following measures:  
Reorient or relocate the receiving antenna.  
Increase the separation between the equipment and receiver.  
Connect the equipment into an outlet on a circuit different from that to which the receiver is connected.  
Consult the dealer or an experienced radio/TV technician for help.  
 
Canadian Department of Communications  
This Class B digital apparatus meets all requirements of the Canadian Interference-Causing Equipment Regulations.  
Cet appareil numérique de la classe B 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 Mark compliance scheme. The Manufacturer includes a DoC for most every hardware product except for  
those bought for OEMs, if also available from an original manufacturer that also markets in the EU, or where compliance is not  
required as for electrically benign apparatus or cables.  
To obtain the DoC for this product, click Declaration of Conformity at ni.com/hardref.nsf/. This website lists the DoCs  
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.  
*
Certain exemptions may apply in the USA, see FCC Rules §15.103 Exempted devices, and §15.105(c). Also available in  
sections of CFR 47.  
** The CE Mark Declaration of Conformity will contain important supplementary information and instructions for the user or  
installer.  
 
Conventions  
The following conventions are used in this manual:  
»
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 on 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.  
Text in this font is also used for proper names of functions or variables.  
 
 
Chapter 1  
Installing the NI 5911 ....................................................................................................1-1  
Acquiring Data with Your NI 5911 ...............................................................................1-3  
Chapter 2  
Triggering and Arming ..................................................................................................2-8  
Analog Trigger Circuit ....................................................................................2-9  
Trigger Hold-Off .............................................................................................2-10  
Memory..........................................................................................................................2-10  
Triggering and Memory Usage .......................................................................2-10  
Multiple-Record Acquisitions........................................................................................2-11  
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Contents  
RTSI Bus and Clock PFI............................................................................................... 2-11  
PFI Lines as Inputs ........................................................................... 2-12  
PFI Lines as Outputs......................................................................... 2-12  
Synchronization .............................................................................................. 2-12  
Appendix A  
Appendix B  
Technical Support Resources  
Glossary  
Index  
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1
Taking Measurements  
with the NI 5911  
Thank you for buying a National Instruments (NI) 5911 digitizer, featuring  
the FLEX ADC. This chapter provides information on installing,  
connecting signals to, and acquiring data from your NI 5911.  
Installing the NI 5911  
There are two main steps involved in installation:  
1. Install the NI-SCOPE driver software. You use this driver to write  
programs to control your NI 5911 in different application development  
environments (ADEs). Installing NI-SCOPE also allows you to  
interactively control your NI 5911 with the Scope Soft Front Panel.  
2. Install your NI 5911. For step-by-step instructions for installing  
NI-SCOPE and the NI 5911, see Where to Start with Your NI Digitizer.  
For multiple-board considerations, see the Operating Environment section  
in Appendix A, Specifications, of this manual.  
Connecting Signals  
Figure 1-1 shows the front panel for the NI 5911. The front panel contains  
three connectorsa BNC connector, an SMB connector, and a 9-pin mini  
circular DIN connector (see Figure 1-2).  
The BNC connector is for attaching the analog input signal you wish 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 for external triggers and for  
generating a probe compensation signal. The SMB connector is PFI1.  
The DIN connector gives you access to an additional external trigger line.  
The DIN connector can be used to access PFI2.  
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.  
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Chapter 1  
Taking Measurements with the NI 5911  
CH0  
PFI1  
PFI2  
(DIN)  
Figure 1-1. NI 5911 Connectors  
9
8
7
6
5
2
4
1
3
1
3
+5 Volts (Fused)  
GND  
Reserved  
4
5
6
Reserved  
Reserved  
PFI 2  
7
8
9
Reserved  
Reserved  
Reserved  
Figure 1-2. 9-Pin Mini Circular DIN Connector  
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Chapter 1  
Taking Measurements with the NI 5911  
Acquiring Data with Your NI 5911  
You can acquire data either programmaticallyby writing an application  
for your NI 5911or interactively with the Scope Soft Front Panel.  
Programmatically Controlling Your NI 5911  
To help you get started programming your NI 5911, NI-SCOPE comes  
with examples that you can use or modify.  
You can find examples for these different ADEs:  
LabVIEWGo to Program Files\National Instruments\  
LabVIEW\Examples\Instr\niScopeExamples\  
LabWindows/CVI, C, and Visual Basic with Windows 98/95Go to  
vxipnp\win95\Niscope\Examples\c\  
LabWindows/CVI, C, and Visual Basic with Windows 2000/NTGo  
to vxipnp\winnt\Niscope\Examples\  
For information about using NI-SCOPE to programmatically control your  
digitizer, refer to your NI-SCOPE Software User Manual. Other resources  
include the NI-SCOPE Instrument Driver Quick Reference Guide. It  
contains abbreviated information on the most commonly used functions  
and LabVIEW VIs. For more detailed function reference help, see the  
NI-SCOPE Function Reference Help file, 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 Your NI 5911 with the Scope Soft Front Panel  
The Scope Soft Front Panel allows you to interactively control your  
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  
file for instructions on configuring the Scope Soft Front Panel for your  
specific application.  
Note Press F1 with the Scope Soft Front Panel running to access the Scope Soft Front  
Panel Help.  
© National Instruments Corporation  
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2
Hardware Overview  
This chapter includes an overview of the NI 5911, explains the operation of  
each functional unit making up your NI 5911, and describes the signal  
connections. Figure 2-1 shows a block diagram of the NI 5911.  
Analog Input  
Connector  
AC/DC Coupling  
Protect/  
Calibration  
Mux  
PGIA  
A/D Converter  
100 MHz, 8-Bit  
Noise  
Shaper  
Calibration  
Generator  
Timing IO/  
Memory Control  
Reference  
Clock  
Digital IO  
Connector  
Digital Signal  
Processor  
Capture  
Memory  
Data  
Figure 2-1. NI 5911 Block Diagram  
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 analog-to-digital converter (ADC)  
regardless of source impedance, source amplitude, DC biasing, or  
common-mode noise voltages.  
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Hardware Overview  
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  
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+  
+
Vout  
PGIA  
V–  
Ground Noise  
Figure 2-2. Noise-Free Measurements of Signal  
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 will result in higher distortion and  
lower bandwidth.  
The negative input of the amplifier is grounded to PC ground through a  
10 kresistor. 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 kresistance 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.  
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Chapter 2  
Hardware Overview  
Input Ranges  
To optimize the ADC resolution, you can select different gains for the  
PGIA. In this way, you can scale your input signal to match the full input  
range of the converter. The NI 5911 PGIA offers seven different 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  
10 V  
5 V  
Input Protection Threshold  
10 V  
5 V  
5 V  
5 V  
5 V  
5 V  
5 V  
2 V  
1 V  
0.5 V  
0.2 V  
0.1 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 impedance of the NI 5911 PGIA is 1 Mbetween 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:  
VsRin  
Vm = -------------------  
Rs + Rin  
where Vm is the measured voltage, Vs is the source voltage, Rs is the external  
source impedance, and Rin 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,  
© National Instruments Corporation  
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Hardware Overview  
if the device has 1 Moutput impedance, your measured signal will be  
one-half 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 you measure, according to  
the formula Rs × 1 nA, where Rs is the external source impedance. For  
example, if the device you have attached to the NI 5911 has an output  
impedance of 10 k, typically the offset voltage is 10 µV (10 k×1 nA).  
Input Protection  
The NI 5911 features input-protection circuits that protect both the positive  
and negative analog input from damage from AC and DC signals up to  
42 V.  
If the voltage at one of these inputs exceeds a threshold voltage, Vtr, the  
input clamps to Vtr and a resistance of 100 kis inserted in the path to  
minimize input currents to a nonharmful level.  
The protection voltage, Vtr,is input range dependent, as shown in Table 2-1.  
AC Coupling  
When you need to 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. Input  
coupling can be selected via software. See the Digitizer Basics appendix in  
your NI-SCOPE Software User Manual for more information on input  
coupling.  
Oscilloscope and Flexible Resolution Modes  
In oscilloscope 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 differs from oscilloscope mode in two ways: it has  
higher resolution (sampling rate dependent), and the signal bandwidth is  
limited to provide antialiasing protection. This mode is useful for spectral  
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Hardware Overview  
analysis, distortion analysis, and other measurements for which high  
resolution is crucial.  
Oscilloscope 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  
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 oscilloscope mode, all signals up to 100 MHz are passed to the ADC.  
You need to ensure that your signal is band-limited to prevent aliasing.  
Aliasing and other sampling terms are described more thoroughly in your  
NI-SCOPE Software User Manual.  
Sampling Methods—Real-Time and RIS  
There are two sampling methods available in oscilloscope mode, real-time  
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 232.  
RIS sampling can be used on repetitive signals to effectively extend the  
sampling rate above 100 MS/s. In RIS mode, you can sample at rates of  
100 MS/s × n, where n is a number from 2 to 10.  
Flexible Resolution Mode  
Table 2-2 shows the relationship between the available sampling rates,  
resolution, and the corresponding bandwidth for flexible resolution mode.  
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Hardware Overview  
Table 2-2. Available Sampling Rates and Corresponding Bandwidth  
in Flexible Resolution Mode  
Sampling Rate  
12.5 MS/s  
5 MS/s  
Resolution  
11 Bits  
Bandwidth  
3.75 MHz  
2 MHz  
14 Bits  
2.5 MS/s  
1 MS/s  
15.5 Bits  
17.5 Bits  
18 Bits  
1 MHz  
400 kHz  
200 kHz  
80 kHz  
40 kHz  
20 kHz  
8 kHz  
500 kS/s  
200 kS/s  
100 kS/s  
50 kS/s  
18.5 Bits  
19 Bits  
19.5 Bits  
20.5 Bits  
21 Bits  
20 kS/s  
10 kS/s  
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 will 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.  
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Chapter 2  
Hardware Overview  
Calibration  
The NI 5911 can be calibrated for very high accuracy and resolution due  
to 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.  
Internal calibration is performed via a software command that  
compensates for drifts caused by environmental temperature changes. You  
can internally calibrate your NI 5911 without any external equipment  
connected. External calibration recalibrates the device when the specified  
calibration interval has expired. See Appendix A, Specifications, for the  
calibration interval. External calibration requires you to connect an external  
precision voltage reference to the device.  
Internally Calibrating the NI 5911  
Internally calibrate your NI 5911 with a software function or a  
LabVIEW VI. See Chapter 3, Common Functions and Examples, of your  
NI-SCOPE Software User Manual for step-by-step instructions for  
calibrating your digitizer.  
When Internal 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 no longer is able to stabilize the temperature,  
and signal data becomes inaccurate. When the temperature range has been  
exceeded, you receive a warning, and you need to perform an internal  
calibration.  
What Internal Calibration Does  
Internal 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  
a certain amount of time to stabilize at the new temperature. This  
temperature stabilization accounts for the majority of the calibration  
time.  
Gain and offset are calibrated for each individual input range.  
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Chapter 2  
Hardware Overview  
The linearity of the ADC is calibrated using an internal sinewave  
generator as reference.  
The time-to-digital converter used for RIS measurements is calibrated.  
Caution Do not apply high-amplitude or high-frequency signals to the NI 5911 during  
internal calibration. For optimal calibration performance, disconnect the input signal from  
the NI 5911.  
Why Errors 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 is unable to  
maintain the temperature within specification, an error is generated. This  
error indicates that the temperature of the ADC is out of range and should  
be recalibrated by performing an internal calibration. During acquisition in  
flexible resolution mode, an error will be 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 due to the digital filtering that  
takes place on the acquired data. Therefore, an error occurs to let you know  
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 will need 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  
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 can also call a software function to trigger the board. 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 will be accepted.  
Note The NI 5911 does not support delayed triggering.  
NI 5911 User Manual  
2-8  
 
ni.com  
           
Chapter 2  
Hardware Overview  
High  
Level  
+
Analog  
Input  
COMP  
Gain  
Analog  
Trigger  
Circuit  
ATC_OUT  
COMP  
Low  
Level  
a. Analog Trigger Circuit  
Software  
ATC_OUT  
RTSI <0..6>  
Trigger  
Arm  
7
2
PFI1, PFI2  
b. Trigger and Arm Sources  
Figure 2-3. Trigger Sources  
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.  
This means that for a 10 V input range, the trigger can be set in increments  
of 20 V/170 = 118 mV. There may also be a hysteresis value 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 a more complete discussion of triggering, see Chapter 3,  
Common Functions and Examples, of your NI-SCOPE Software User  
Manual.  
© National Instruments Corporation  
2-9  
NI 5911 User Manual  
 
       
Chapter 2  
Hardware Overview  
Trigger Hold-Off  
Trigger hold-off 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 hold-off  
time. After completing its current record, the digitizer records no data and  
accepts no triggers until the hold-off counter runs out. When the counter  
runs out, the next record begins and a trigger may be accepted. Setting a  
hold-off time shorter than posttrigger acquisition time has no effect, as  
triggers are always rejected during an acquisition.  
Note Time to acquire posttrigger samples is (posttrigger samples)/(sample rate  
(megahertz)).  
Trigger hold-off is provided in hardware using a 32-bit counter clocked  
by a 25 MHz internal timebase. With this configuration, you can select  
a hardware hold-off value of 40 ns to 171.8 s in increments of 40 ns. For  
more information regarding trigger hold-off, see the Common Trigger  
Parameters section in Chapter 3, Common Functions and Examples, of  
your NI-SCOPE Software User Manual.  
Memory  
The NI 5911 allocates at least 4 kB of onboard memory for every  
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 oscilloscope mode samples or 1,000 32-bit  
flexible resolution mode samples. Software allows you to specify buffers  
of less than these minimum sizes. However, the minimum number of points  
are still acquired into onboard memory, but only the specified number of  
points are transferred 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.  
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.  
NI 5911 User Manual  
2-10  
ni.com  
 
           
Chapter 2  
Hardware Overview  
Multiple-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 is a multiple-record  
acquisition. To perform multiple-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 1024 records if your NI 5911 is equipped with 4 MB of  
onboard memory, or 4096 records with 16 MB. Software intervention after  
the initial setup is not required.  
Multiple-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 multiple-record acquisitions and dead time, see  
the Making a Multiple-Record Acquisition section in Chapter 5, Tasks and  
Examples, of your NI-SCOPE Software User Manual.  
RTSI Bus and Clock PFI  
The 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 5911s.  
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.  
© National Instruments Corporation  
2-11  
NI 5911 User Manual  
 
           
Chapter 2  
Hardware Overview  
PFI Lines as Inputs  
You can select PFI1 or PFI2 as inputs for a trigger or a reference clock.  
Please see the Synchronization section below for more information about  
the use of reference clocks in the NI 5911.  
PFI Lines as Outputs  
You can select PFI1 or PFI2 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.  
Synchronization  
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 may also output its 10 MHz reference on the RTSI bus clock  
line or a PFI line so that other NI 5911s 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 different  
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 NI RTSI bus cable. One of the RTSI bus triggers must be  
designated as a synchronization line. This line will be 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. For more information about synchronization, refer to  
your NI-SCOPE Software User Manual.  
NI 5911 User Manual  
2-12  
 
ni.com  
           
A
Specifications  
This appendix lists the specifications of the NI 5911. These specifications  
Bandwidth.............................................. 100 MHz maximum,  
see Table 2-2, Available  
Sampling Rates and  
Corresponding Bandwidth in  
Flexible Resolution Mode  
Number of channels ............................... 1  
Number of flexible resolution ADC....... 1  
Max sample rate..................................... 1 GS/s repetitive,  
100 MS/s single shot  
Resolution  
Sample Rate  
100/n* MS/s  
Mode  
Effective Resolution  
8 Bits  
Oscilloscope  
12.5 MS/s  
5 MS/s  
Flexible Resolution  
Flexible Resolution  
Flexible Resolution  
Flexible Resolution  
Flexible Resolution  
Flexible Resolution  
Flexible Resolution  
Flexible Resolution  
11 Bits  
14 Bits  
2.5 MS/s  
1 MS/s  
15.5 Bits  
17.5 Bits  
18 Bits  
500 kS/s  
200 kS/s  
100 kS/s  
50 kS/s  
18.5 Bits  
19 Bits  
19.5 Bits  
© National Instruments Corporation  
A-1  
NI 5911 User Manual  
 
         
Appendix A  
Specifications  
Sample Rate  
20 kS/s  
Mode  
Effective Resolution  
20.5 Bits  
Flexible Resolution  
Flexible Resolution  
10 kS/s  
21 Bits  
* 1<n<232 in oscilloscope mode  
Sample onboard memory........................4 MB or 16 MB  
Memory sample depth  
Sampling  
Frequency  
Sample Depth  
(4 MB)  
Sample Depth  
(16 MB)  
Mode  
100/n* MS/s Oscilloscope  
4 MS  
1 MS  
1 MS  
1 MS  
1 MS  
1 MS  
1 MS  
1 MS  
1 MS  
1 MS  
1 MS  
16 MS  
4 MS  
4 MS  
4 MS  
4 MS  
4 MS  
4 MS  
4 MS  
4 MS  
4 MS  
4 MS  
12.5 MS/s  
5 MS/s  
Flexible Resolution  
Flexible Resolution  
Flexible Resolution  
Flexible Resolution  
Flexible Resolution  
Flexible Resolution  
Flexible Resolution  
Flexible Resolution  
Flexible Resolution  
Flexible Resolution  
2.5 MS/s  
1 MS/s  
500 kS/s  
200 kS/s  
100 kS/s  
50 kS/s  
20 kS/s  
10 kS/s  
* 1<n<232 in oscilloscope mode  
Vertical sensitivity (input ranges)  
Input Range  
Noise Referred to Input  
10 V  
5 V  
2 V  
1 V  
174 dBfs/ Hz  
168 dBfs/ Hz  
160 dBfs/ Hz  
154 dBfs/ Hz  
NI 5911 User Manual  
A-2  
ni.com  
 
   
Appendix A  
Specifications  
Input Range  
Noise Referred to Input  
0.5 V  
0.2 V  
0.1 V  
148 dBfs/ Hz  
140 dBfs/ Hz  
134 dBfs/ Hz  
Acquisition Characteristics  
Accuracy  
DC gain accuracy................................... 0.05% signal 0.0001% fs  
for all input ranges at 1 MS/s in  
flexible resolution mode  
DC offset accuracy................................. 0.1 mV 0.01% fs  
for all input ranges at 1 MS/s in  
flexible resolution mode  
Input coupling ........................................ DC and AC, software selectable  
AC coupling cut-off frequency  
(3 dB) ................................................... 2.3 Hz 13%  
Input impedance..................................... 1 M2%  
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, (Fin < 1 kHz)  
© National Instruments Corporation  
A-3  
NI 5911 User Manual  
 
     
Appendix A  
Specifications  
Filtering  
Sampling  
Filter  
Mode  
Alias  
Attenuation  
Frequency  
100/n* MS/s  
12.5 MS/s  
Bandwidth  
100 MHz  
Ripple  
3 dB  
Oscilloscope  
N/A  
Flexible  
3.75 MHz  
0.2 dB  
60 dB  
Resolution  
5 MS/s  
2.5 MS/s  
1 MS/s  
Flexible  
Resolution  
2 MHz  
1 MHz  
400 kHz  
200 kHz  
80 kHz  
40 kHz  
20 kHz  
8 kHz  
0.1 dB  
70 dB  
80 dB  
80 dB  
80 dB  
80 dB  
80 dB  
80 dB  
80 dB  
80 dB  
Flexible  
Resolution  
0.05 dB  
Flexible  
Resolution  
0.005 dB  
0.005 dB  
0.005 dB  
0.005 dB  
0.005 dB  
0.005 dB  
0.005 dB  
500 kS/s  
200 kS/s  
100 kS/s  
50 kS/s  
20 kS/s  
10 kS/s  
Flexible  
Resolution  
Flexible  
Resolution  
Flexible  
Resolution  
Flexible  
Resolution  
Flexible  
Resolution  
Flexible  
4 kHz  
Resolution  
* 1<n<232 in oscilloscope mode  
Dynamic Range  
Noise (excluding input-referred noise)  
Sampling Frequency  
Bandwidth  
Noise Density  
Total Noise  
100 MHz  
3.75 MHz  
2 MHz  
120 dBfs/ Hz  
135 dBfs/ Hz  
150 dBfs/ Hz  
155 dBfs/ Hz  
43 dBfs  
64 dBfs  
83 dBfs  
91 dBfs  
100/n* MS/s  
12.5 MS/s  
5 MS/s  
1 MHz  
2.5 MS/s  
NI 5911 User Manual  
A-4  
 
ni.com  
   
Appendix A  
Specifications  
Sampling Frequency  
Bandwidth  
Noise Density  
Total Noise  
400 kHz  
200 kHz  
80 kHz  
40 kHz  
20 kHz  
8 kHz  
160 dBfs/ Hz  
160 dBfs/ Hz  
160 dBfs/ Hz  
160 dBfs/ Hz  
160 dBfs/ Hz  
160 dBfs/ Hz  
160 dBfs/ Hz  
104 dBfs  
107 dBfs  
111 dBfs  
114 dBfs  
117 dBfs  
121 dBfs  
124 dBfs  
1 MS/s  
500 kS/s  
200 kS/s  
100 kS/s  
50 kS/s  
20 kS/s  
4 kHz  
10 kS/s  
* 1<n<232 in oscilloscope mode  
Distortion  
SFDR for input  
0 dBfs  
SFDR for input  
SFDR for input  
60 dBfs (typical)  
Sampling Frequency  
100 MS/s  
12.5 MS/s  
5 MS/s  
20 dBfs  
50 dB  
65 dB  
50 dB  
N/A  
85 dB  
125 dB  
130 dB  
135 dB  
145 dB  
150 dB  
160 dB  
160 dB  
160 dB  
160 dB  
160 dB  
70 dB  
90 dB  
2.5 MS/s  
1 MS/s  
75 dB  
95 dB  
85 dB  
105 dB  
110 dB  
110 dB  
110 dB  
110 dB  
110 dB  
110 dB  
500 kS/s  
200 kS/s  
100 kS/s  
50 kS/s  
90 dB  
100 dB  
100 dB  
100 dB  
100 dB  
100 dB  
20 kS/s  
10 kS/s  
Timebase System  
Reference clock...................................... 10 MHz  
Clock accuracy (as master) .................... 10 MHz 50 ppm  
© National Instruments Corporation  
A-5  
NI 5911 User Manual  
 
   
Appendix A  
Specifications  
Clock input tolerance (as slave)..............10 MHz 100 ppm  
Clock jitter ..............................................<75 pSrms, independent of  
reference clock source  
Clock compatibility ...............................TTL for both input and output  
Interpolator resolution  
(repetitive only) ......................................1 ns  
Sampling clock frequencies  
Oscilloscope mode...........................100 MHz/n, where 1<n<232  
Flexible resolution mode.................100 MHz/n, where n = 8; 20; 50;  
100; 200; 500; 1,000; 2,000;  
5,000; 10,000  
Reference clock sources .........................PFI lines, RTSI clock, or onboard  
Phase difference between  
multiple instruments ...............................<5 ns, at any input frequency  
<100 MHz, from input connector  
to input connector  
Triggering Systems  
Modes .....................................................Above threshold, below  
threshold, between thresholds,  
outside thresholds  
Source .....................................................CH0, RTSI<0..6>, PFI 1,2  
Slope .......................................................Rising/falling  
Hysteresis................................................Full-scale voltage/n, where n is  
between 1 and 170; full-scale  
voltage on TRIG is fixed to 5 V  
(without external attenuation)  
Coupling .................................................AC/DC on CH0, TRIG  
Pretrigger depth ......................................1 to 16 million samples  
Posttrigger depth.....................................1 to 16 million samples  
Holdoff time ...........................................5 µs 171.85 s in increments  
of 40 ns  
NI 5911 User Manual  
A-6  
 
ni.com  
 
Appendix A  
Specifications  
Sensitivity............................................... 170 steps in full-scale voltage  
range  
TRIG input range ................................... 5 V (without external  
attenuation)  
TRIG input impedance........................... 1 M1% in parallel  
with 30 pF 15 pF  
TRIG input protection............................ 42 V [(DC + peak AC) < 10 kHz,  
without external attenuation]  
Acquisition Modes  
RIS ......................................................... 1 GS/s down to 200 MS/s  
effective sample rate, repetitive  
signals only. Data is interleaved  
in software.  
RIS accuracy .......................................... <0.5 ns  
Single-shot ............................................. 100 MS/s down to 10 kS/s sample  
rate for transient and repetitive  
signals  
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  
Analog input CH0........................... BNC female  
Digital triggers ................................ SMB female, 9-pin mini DIN  
© National Instruments Corporation  
A-7  
NI 5911 User Manual  
 
     
Appendix A  
Specifications  
Operating Environment  
Note Multiple NI 5911s 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 5911s or adding a fan.  
Ambient temperature ..............................5 to 40 °C  
Relative humidity ...................................10% to 90%, noncondensing  
Storage Environment  
Ambient temperature ..............................20 to 65 °C  
EMC Compliance  
Calibration  
CE2001, FCC  
Internal....................................................Internal calibration is done upon  
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...................................................Internal reference requires  
recalibration  
Interval.............................................1 year  
Warm-up time.........................................1 minute  
NI 5911 User Manual  
A-8  
 
ni.com  
         
B
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.com.  
NI Developer Zone  
The NI Developer Zone at ni.com/zoneis the essential resource for  
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 ni.comfor online course schedules,  
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.  
© National Instruments Corporation  
B-1  
NI 5911 User Manual  
 
             
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 ni.com. Branch office Web sites provide  
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 5911 User Manual  
B-2  
ni.com  
 
 
Glossary  
Prefix  
p-  
Meanings  
pico-  
Value  
1012  
109  
106  
103  
103  
n-  
nano-  
micro-  
milli-  
µ-  
m-  
k-  
kilo-  
M-  
G-  
mega-  
giga-  
106  
109  
Symbols  
%
+
/
percent  
positive of, or plus  
negative of, or minus  
per  
°
degree  
plus or minus  
ohm  
A
A
amperes  
A/D  
AC  
analog to digital  
alternating current  
© National Instruments Corporation  
G-1  
NI 5911 User Manual  
 
 
Glossary  
AC coupled  
ADC  
the passing of a signal through a filter network that removes the  
DC component of the signal  
analog-to-digital converteran 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  
amplitude flatness  
attenuate  
a type of signal conditioning that improves accuracy in the resulting  
digitized signal and reduces noise  
a measure of how close to constant the gain of a circuit remains over a range  
of frequencies  
to reduce in magnitude  
B
b
bitone binary digit, either 0 or 1  
B
byteeight 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  
bus  
temporary storage for acquired or generated data (software)  
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.  
C
C
Celsius  
channel  
pin or wire lead to which you apply or from which you read the analog or  
digital signal  
NI 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 ratioa measure of an instruments ability to  
reject interference from a common-mode signal, usually expressed in  
decibels (dB)  
counter/timer  
coupling  
a circuit that counts external pulses or clock pulses (timing)  
the manner in which a signal is connected from one location to another  
D
dB  
decibelthe 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 board, card, or pad. The NI 5911 is an example  
of a device.  
differential input  
double insulated  
drivers  
an analog input consisting of two terminals, both of which are isolated from  
computer ground, whose difference is measured  
a device that contains the necessary insulating structures to provide electric  
shock protection without the requirement of a safety ground connection  
software that controls a specific hardware instrument  
E
EEPROM  
electrically erasable programmable read-only memoryROM that can be  
erased with an electrical signal and reprogrammed  
equivalent time  
sampling  
any method used to sample signals in such a way that the apparent sampling  
rate is higher than the real sampling rate  
event  
the condition or state of an analog or digital signal  
© National Instruments Corporation  
G-3  
NI 5911 User Manual  
 
Glossary  
F
filtering  
a type of signal conditioning that allows you to filter unwanted signals from  
the signal you are trying to measure  
fs  
full-scaletotal voltage in the input range. A 10 V input range is 20 V fs  
G
gain  
the factor by which a signal is amplified, sometimes expressed in decibels  
H
hardware  
the physical components of a computer system, such as the circuit boards,  
plug-in boards, chassis, enclosures, peripherals, cables, and so on  
harmonics  
Hz  
multiples of the fundamental frequency of a signal  
hertzper second, as in cycles per second or samples per second  
I
I/O  
input/outputthe transfer of data to/from a computer system involving  
communications channels, operator interface devices, and/or data  
acquisition and control interfaces  
in.  
inches  
inductance  
input bias current  
input impedance  
the relationship of induced voltage to current  
the current that flows into the inputs of a circuit  
the measured resistance and capacitance between the input terminals of a  
circuit  
instrument driver  
interrupt  
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.  
a computer signal indicating that the CPU should suspend its current task  
to service a designated activity  
NI 5911 User Manual  
G-4  
ni.com  
 
Glossary  
interrupt level  
ISA  
the relative priority at which a device can interrupt  
industry standard architecture  
K
k
kilothe standard metric prefix for 1,000, or 103, used with units of  
measure such as volts, hertz, and meters  
kS  
1,000 samples  
L
LabVIEW  
laboratory virtual instrument engineering workbench—a graphical  
programming ADE developed by National Instruments  
LSB  
least significant bit  
M
m
meters  
MB  
megabytes of memory  
see buffer  
memory buffer  
MS  
million samples  
most significant bit  
MSB  
© National Instruments Corporation  
G-5  
NI 5911 User Manual  
 
Glossary  
N
noise  
an undesirable electrical signalnoise 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.  
O
Ohms 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  
P
passband  
the frequency range that a filter passes without attenuation  
PCI  
Peripheral Component Interconnecta 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 5911 User Manual  
G-6  
ni.com  
 
 
Glossary  
pretriggering  
PXI  
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  
PCI eXtensions for Instrumentation. PXI is an open specification that  
builds off the CompactPCI specification by adding  
instrumentation-specific features.  
R
R
resistor  
RAM  
random-access memory  
sampling that occurs immediately  
real-time sampling  
random interleaved  
sampling  
method of increasing the sample rate by repetitively sampling a repeated  
waveform  
resolution  
the smallest signal increment that can be detected by a measurement  
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.  
rms  
root mean squarea measure of signal amplitude; the square root of the  
average value of the square of the instantaneous signal amplitude  
ROM  
read-only memory  
RTSI bus  
real-time system integration busthe National Instruments timing bus that  
connects devices directly, by means of connectors on top of the boards, for  
precise synchronization of functions  
S
s
seconds  
samples  
S
S/s  
samples per secondused to express the rate at which an instrument  
samples an analog signal. 100 MS/s would equal 100 million samples each  
second.  
© National Instruments Corporation  
G-7  
NI 5911 User Manual  
 
Glossary  
sense  
in four-wire resistance the sense measures the voltage across the resistor  
being excited by the excitation current  
settling time  
source impedance  
the amount of time required for a voltage to reach its final value within  
specified limits  
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  
T
temperature  
coefficient  
the percentage that a measurement will vary according to temperature.  
See also thermal drift  
thermal drift  
measurements that change as the temperature varies  
thermal EMFs  
thermal electromotive forcesvoltages generated at the junctions of  
dissimilar metals that are functions of temperature. Also called  
thermoelectric potentials.  
thermoelectric  
potentials  
see thermal EMFs  
transfer rate  
the rate, measured in bytes/s, at which data is moved from source to  
destination after software initialization and set up operations; the maximum  
rate at which the hardware can operate  
trigger  
any event that causes or starts some form of data capture  
U
undersampling  
sampling at a rate lower than the Nyquist frequency—can cause aliasing  
the number of output updates per second  
update rate  
NI 5911 User Manual  
G-8  
ni.com  
 
   
Glossary  
V
V
volts  
VAC  
VDC  
Verror  
VI  
volts alternating current  
volts direct current  
voltage error  
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  
Vrms  
volts, root mean square value  
W
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  
© National Instruments Corporation  
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Index  
conventions used in the manual, vi  
A
AC coupling, 2-4  
accuracy characteristics, A-3  
acquisition  
multiple record, 2-11  
(PGIA)  
Scope Soft Front Panel, 1-3  
acquisition characteristics specifications  
accuracy, A-3  
common-mode characteristics, A-3  
distortion, A-5  
dynamic range, A-4  
AC coupling, 2-4  
differential input, 2-2  
input bias, 2-4  
input impedance, 2-3  
input protection, 2-4  
input ranges, 2-3  
filtering, A-4  
acquisition modes specifications, A-7  
noise-free signal measurement (figure), 2-2  
DIN connector, 1-1  
dynamic range specifications, A-4  
B
bias, input, 2-4  
EMC compliance, A-8  
C
calibration  
errors occurring during acquisition, 2-8  
external calibration, 2-8  
internal calibration, 2-7  
specifications, A-8  
flexible resolution mode  
clock lines, 2-12  
common-mode characteristics, A-3  
connectors  
available sampling rates (table), 2-6  
definition, 2-5  
memory sample depth (table), A-2  
purpose and use, 2-6  
BNC connector, 1-1  
DIN connector, 1-1  
location on front panel (figure), 1-2  
SMB connector, 1-1  
sampling rate specifications (table), A-1  
© National Instruments Corporation  
I-1  
NI 5911 User Manual  
 
 
Index  
input protection circuits, 2-4  
input ranges, 2-3  
installing NI 5911, 1-1  
G
grounding considerations, 2-2  
H
hardware overview  
memory  
See also specifications  
acquisition system  
description, 2-10  
triggering and memory usage, 2-10  
calibration, 2-7  
amplifier (PGIA)  
National Instruments Web support, B-1  
NI 5911  
AC coupling, 2-4  
See also hardware overview  
block diagram, 2-1  
connectors  
differential input, 2-2  
(figure), 2-2  
BNC connector, 1-1  
DIN connector, 1-1  
location on front panel (figure), 1-2  
SMB connector, 1-1  
front panel (figure), 1-2  
installing, 1-1  
Scope Soft Front Panel, 1-3  
specifications  
flexible resolution mode, 2-5  
memory, 2-10  
multiple record acquisition, 2-11  
oscilloscope mode, 2-5  
RTSI bus trigger and clock lines, 2-11  
trigger hold-off, 2-10  
triggering and arming  
analog trigger circuit, 2-9  
acquisition characteristics, A-3  
acquisition modes, A-7  
acquisition system, A-1  
NI Developer Zone, B-1  
NI-SCOPE driver software  
installing, 1-1  
programmatically controlling  
NI 5911, 1-3  
noise-free measurements, 2-2  
I
impedance  
formula for impedance divider, 2-3  
input and output impedance, 2-3  
input bias, 2-4  
input impedance, 2-3  
NI 5911 User Manual  
I-2  
 
ni.com  
acquisition characteristics  
accuracy, A-3  
O
oscilloscope mode  
common-mode characteristics, A-3  
distortion, A-5  
dynamic range, A-4  
definition, 2-4  
purpose and use, 2-5  
Real-Time and RIS sampling  
filtering, A-4  
acquisition modes, A-7  
acquisition system, A-1  
calibration, A-8  
output impedance, 2-3  
P
EMC compliance, A-8  
operating environment, A-8  
physical, A-7  
PFI lines  
as inputs, 2-12  
power requirements, A-7  
timebase system, A-5  
triggering systems, A-6  
storage environment specifications, A-8  
as outputs, 2-12  
overview, 2-11  
PGIA. See differential programmable gain  
physical specifications, A-7  
power requirement specifications, A-7  
programmable gain input amplifier PGIA. See  
amplifier (PGIA)  
technical support resources, B-1  
timebase system specifications, A-5  
triggering and arming  
R
Random Interleaved Sampling (RIS), 2-5  
real-time sampling, 2-5  
analog trigger circuit, 2-9  
memory usage, 2-10  
RIS (Random Interleaved Sampling), 2-5  
RTSI bus trigger and clock lines  
purpose and use, 2-11  
trigger sources (figure), 2-9  
S
vertical sensitivity specifications, A-2  
sampling methodsreal-time and RIS, 2-5  
sampling rate, flexible resolution mode  
(table), 2-6  
W
Web support from National Instruments, B-1  
worldwide technical support, B-2  
Scope Soft Front Panel, 1-3  
SMB connector, 1-1  
© National Instruments Corporation  
I-3  
NI 5911 User Manual  
 

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