24-Bit, 204.8 kS/s Dynamic Signal Acquisition and Generation
NI 4461, NI 4462
• 2 or 4 simultaneously sampled
analog inputs
• 2 simultaneously updated
analog outputs (NI 4461 only)
• 118 dB dynamic range, 24-bit resolution
• 204.8 kS/s maximum sampling rate
• 92 kHz alias-free bandwidth
• Input range from ±316 mV to 42.4 V
• 6 gain settings
• AC/DC coupling
• Antialiasing and anti-imaging protection
• IEPE conditioning – software-configurable
• Multimodule synchronization
Operating Systems
• Windows 2000/NT/XP
Recommended Software
• LabVIEW
• LabVIEW Real-Time Module
• LabVIEW Sound and
Vibration Toolkit
• LabVIEW Order Analysis Toolkit
• LabWindows/CVI
• Measurement Studio
Measurement Services Software
(included)
• NI-DAQmx
Calibration Certificate Available
Product
NI 4461
NI 4462
Bus
PXI, PCI
PXI, PCI
Analog
Input
Sampling
Inputs Resolution
Rate
2
24 bits
204.8 kS/s
4
24 bits
204.8 kS/s
Input
Range
±316 mV to 42.4 V
±316 mV to 42.4 V
Input
Configuration
Differential/pseudodifferential
Differential/pseudodifferential
Analog
Outputs
2
0
Output
Resolution
24 bits
–
Update
Rate
204.8 kS/s
–
Output
Triggering
Range
±100 mV to 10 V Analog/digital
–
Analog/digital
Table 1. NI 446x Channel, Speed, and Resolution Specifications
Overview
The National Instruments 4461 and 4462 are high-accuracy data acquisition
devices specifically designed for sound and vibration applications. The
devices include the hardware and software needed to make precision
measurements with microphones, accelerometers, and other transducers
that have very large dynamic ranges. Common applications for the
NI 446x include audio test, automotive test, noise, vibration, and
harshness (NVH) analysis, and machine condition monitoring (MCM).
The NI 446x devices offer a complete range of functionality for sound
and vibration monitoring and analysis applications. With either two inputs
and two outputs, or four inputs, they are ideal for applications where
simultaneous generation and acquisition of noise, vibration, and acoustic
signals are required. You can synchronize the acquisition clock of your
NI 446x with other instruments in your system for mixed-signal
applications. Both analog and digital triggering are available on an NI 446x.
Analog Inputs
The analog input channels of NI 446x devices have 24-bit resolution ADCs
that are simultaneously sampled at software-programmable rates for
standard audio applications, such as 44.1 kS/s (the standard rate used in
CD players), 48.0 kS/s (the rate used in digital audio tape (DAT) recorders
and other digital audio equipment), 96.0 kS/s, and 192 kS/s. An NI 446x is
well-suited for audio, sound, and vibration analysis applications.
The analog inputs offer programmable AC/DC coupling. A programmable
gain amplifier stage on the inputs gives gain selection from -20 to +30 dB
in 10 dB steps. Furthermore, to provide you with the quietest and
highest-quality analog measurements, the input stage accepts
differential or single-ended signal connections.
Hardware
Applications
•
•
•
•
•
•
Audio Test
Noise, Vibration, and Harshness Test
Machine Condition Monitoring
Sound Power
Structural Vibration
Pass-by Noise
Figure 1. These 24-bit delta-sigma converters deliver outstanding dynamic range.
24-Bit, 204.8 kS/s Dynamic Signal Acquisition and Generation
With 118 dB dynamic range and low noise and distortion, NI 446x
devices can make very accurate frequency-domain measurements. They
have excellent amplitude flatness of ±0.1 dB within the frequency range
of DC to 92 kHz, and have a typical THD of -107 dB.
TTL/CMOS-compatible and is activated by a choice of rising or falling edge.
Triggering is needed in applications that acquire transient signals. When
performing structural analysis by striking a metal beam with a hammer, for
instance, you measure transient vibrations with accelerometers with
acquisition triggered by the hammer impact.
Antialiasing
The analog inputs have both analog and digital filters implemented in
hardware to prevent aliasing. Input signals are first passed through a fixed
analog filter to remove any signals with frequency components beyond the
range of the ADCs. Then digital antialiasing filters automatically adjust
their cutoff frequency to remove any frequency components above half the
programmed sampling rate.
Calibration
National Instruments calibrates the offset voltage and gain accuracy of the
analog inputs and outputs. An onboard precision voltage reference ensures
that the gain and offset remain stable and accurate. NIST-traceable and
ISO 9002-certified calibration certificates are available on request.
Analog Outputs
NI 4461 devices have two channels of 24-bit resolution, high-fidelity
analog output. A common application of the analog output is to stimulate
a system under test while measuring the frequency response with the
analog inputs. The output conversions occur simultaneously at software-
programmable rates up to 204.8 kS/s. The analog output circuitry uses
8-times oversampling interpolators with 64-times oversampling delta-sigma
modulators to offer exceptional spectral purity. Software-programmable
attenuation of 0, 20, or 40 dB is available on the output channels. NI 4461
devices have excellent amplitude flatness of ±0.1 dB within DC to 92 kHz,
and a THD of -95 dB at 1 kHz. You can simultaneously acquire data on the
input channels while updating the output channels.
Figure 2. With application software such as NI LabVIEW, you can conduct
frequency-response, swept-sine, and other common audio measurements.
Software
NI Measurement Services Software
NI 446x devices use NI measurement services software, based on the
NI-DAQmx driver, as the hardware and OS interface. You can build
automated test systems or integrate an NI 446x with other hardware,
including modular instruments and multifunction data acquisition (DAQ)
products, through NI-DAQmx function calls. NI measurement services
software also includes DAQ Assistant, an interactive guide that steps
you through configuring, testing, and programming measurement tasks
and generates the necessary code automatically for National
Instruments LabVIEW, LabWindows/CVI, or Measurement Studio.
Anti-Imaging
NI 4461 output channels have both analog and digital anti-imaging
filters. These filters remove the unwanted out-of-band components
generated when an analog signal is produced from digital data.
The digital filters limit the bandwidth of the output signal to half the
original conversion rate, thereby rejecting images caused by the 8-times
oversampling process. The signals generated by the analog output
circuitry are low-distortion, low-noise, flat-frequency analog signals.
Analysis Software
LabVIEW Sound and Vibration Toolkit
Multimodule Synchronization
For applications requiring more channels, you can synchronize the operation
of two or more NI 446x devices with less than 0.1 deg phase mismatch.
Synchronization is achieved by sharing a digital trigger and clock between
multiple modules. The NI-DAQmx driver software automatically handles the
synchronization of multiple devices in a single task.
Triggering
NI 446x devices offer both analog and digital triggering for signal
acquisition. The source of the trigger can come from any analog input
channel, the external digital trigger input, the PXI trigger bus (PXI devices),
or the RTSI bus (PCI devices). The external digital trigger is 5 V
NI 446x devices are well-suited for audio, acoustic, and vibration
analysis applications. The LabVIEW Sound and Vibration Toolkit
incorporates Express technology to make it easier for you to perform
sound and vibration measurement and analysis. The toolkit includes
LabVIEW Express VIs for:
• Fractional-octave analysis with weighting
• Integrated vibration level
• Weighted sound level
• Zoom power spectrum
• Peak search
• Power in band
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2
24-Bit, 204.8 kS/s Dynamic Signal Acquisition and Generation
• Power spectrum analysis
• Frequency response
• Limit testing
In addition, the LabVIEW Sound and Vibration Toolkit includes
numerous VIs for audio measurements such as gain, phase, distortion,
and swept-sine analysis. Swept-sine is a powerful analysis technique to
measure frequency response. The toolkit also includes simple modular
examples of all of these measurements, so you can quickly combine
analog output, analog input, and data analysis to build a customized
application. In addition, the existing signal generation is extended to
include the tools and examples needed to provide the excitation required
by most audio, noise, and vibration measurements. For example, a library
of 33 waveforms is included in this toolkit to get you up and running fast.
This toolkit also optimizes LabVIEW to perform noise and vibration
measurements. For example, all frequency measurements can perform
zoom FFT analysis to offer improved resolution in the frequency range of
interest. With the built-in fractional-octave analysis, you can perform
measurements with any number of bands at any sampling frequency. NI
446x dynamic signal acquisition devices, combined with this toolkit, offer
compliance with several standards for sound level measurements and
octave analysis:
• IEC 61260 : 1995, class 1
• IEC 61672 : 2002, class 1
• ANSI S1.11 – 2004, class 1
• ANSI S1.4 – 1983
• ANSI S1.42 – 1986
LabVIEW Order Analysis Toolkit
for online processing, you can easily create flexible applications for
condition-based monitoring and predictive maintenance.
The National Instruments 446x dynamic signal acquisition devices are
ideal for acquiring sound and vibration signals to analyze with this toolkit.
Order analysis is a tool for examining dynamic signals generated by
mechanical systems that include rotating or reciprocating components.
With order analysis you can dissect sound, vibration, and other
dynamic signals into components that relate to physical elements of
mechanical systems.
The LabVIEW Order Analysis Toolkit is ideal for machine monitoring,
machine health, and machine efficiency applications. You can use the
toolkit to perform the most common analyses required by MCM
applications, including order tracking, slow-roll compensation, and
vibration integration. With this toolkit, you can develop your application
faster by using built-in examples for order spectra, tachometer
processing, and waterfall plots.
You can also apply order analysis to dynamic signals generated by
mechanical systems that include rotating or reciprocating components,
such as turbines, compressors, pumps, and engines. It is common to use
order analysis in applications such as machine condition monitoring and
noise, vibration, and harshness (NVH) testing. With the added capability
Ordering Information
PCI
NI PCI-4461............................................................................779307-01
NI PCI-4461 with Sound and Vibration Toolkit ....................779308-01
NI PCI-4462............................................................................779309-01
NI PCI-4462 with Sound and Vibration Toolkit ....................779310-01
PXI
NI PXI-4461............................................................................778442-01
NI PXI-4461 with Sound and Vibration Toolkit ....................779039-01
NI PXI-4462............................................................................779131-01
NI PXI-4462 with Sound and Vibration Toolkit ....................779132-01
Includes NI-DAQmx driver software.
BUY NOW!
For complete product specifications, pricing, and accessory
information, call (800) 813 3693 (U.S.) or go to
ni.com/soundandvibration.
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at
ni.com
or
CALL (800) 813 3693 (U.S.)
3
24-Bit, 204.8 kS/s Dynamic Signal Acquisition and Generation
Integrated Electronic Piezoelectric (IEPE)
Current ............................................ 0, 4, or 10 mA,
each channel independently
software-selectable
Compliance ..................................... 24 V min
Channel input impedance
with IEPE enabled ............................... 1 MΩ || 240 pF,
pseudodifferential
Current noise ..........................................<300 pA ⁄ Hz
Specifications
Typical for 25 °C unless otherwise noted.
Analog Input
Number of simultaneously sampled input channels
NI 4461 ........................................... 2
NI 4462 ........................................... 4
Input configuration.............................. Differential or pseudodifferential
(50
Ω
between negative input
and chassis ground), each
channel independently
software-selectable
Input coupling ..................................... AC or DC, each channel
independently software-selectable
A/D converter (ADC) resolution .......... 24 bits
ADC type ............................................. Delta-sigma
Sample rates (f
s
),
samples per second (S/s) ................... 1 kS/s to 204.8 kS/s in 181.9 µS/s
increments, maximum
Transducer Electronic Data Sheet (TEDS) Compatibility
The PCI-4461, PCI-4462, and PXI-4462 inputs work with transducer
electronic data sheet (TEDS) sensors according to the IEEE 1451
Standard. For more information about TEDS, go to
ni.com/info
and enter
rdteds.
Analog Output (NI 4461)
Output Characteristics
Number of output channels ................ 2, simultaneously sampled
Output configuration........................... Differential or pseudodifferential
(50
Ω
to chassis ground on shield),
each channel independently
software-selectable
DAC resolution.................................... 24 bits
DAC type ............................................. Delta-sigma
Update rates (f
s
) ................................. 1 kS/s to 204.8 kS/s in 181.9 µS/s
increments, maximum
Attenuation (dB)
40
20
0
1
Each
Input Signal Ranges
Gain
Log (dB)
-20
-10
0
+10
+20
+30
Full-Scale Range (Peak)
±42.4 V
±31.6 V
±10.0 V
±3.16 V
±1.00 V
±0.316 V
Amplifier Characteristics
Input Impedance
Between positive input
and chassis ground
Between negative input
and chassis ground
Differential Configuration
1 MΩ || 217 pF
1 MΩ || 229 pF
Pseudodifferential Configuration
1 MΩ || 217 pF
50
Ω
Full-Scale Range (V
pk
)
1
±0.1
±1.0
±10.0
output channel range is independently software-selectable.
Input coupling ..................................... AC or DC, software-selectable
Common-mode rejection ratio
(CMRR)............................................ 80 dB with 0 dB gain;
up to 105 dB for higher gain
Output Signal Range
Voltage Output
Short circuit protection ....................... Indefinite protection between
positive and negative
Minimum working load....................... 600
Ω
Dynamic Characteristics
Specification
Alias-free bandwidth (BW), (passband)
Alias rejection, minimum
Low-Frequency Alias Rejection Disabled
DC to 0.4535
f
s
120 dBc
Dynamic Characteristics
Image rejection ................................... 75 dB min < 768 kHz
66 dB min > 768 kHz
AO Flatness
20 Hz to 20 kHz............................... ±0.008 dB max
20 Hz to 92.1 kHz............................ ±0.1 dB max
AO dynamic range............................... 113 dBFS, 0 dB attenuation,
102.5 kS/s (30 kHz bandwidth)
AO THD ............................................... -97 dBc up to 20 kHz
AO interchannel gain mismatch ......... 0.03 dB, 20 Hz to 92.1 kHz
AC coupling
-3 dB cutoff frequency.................... 3.4 Hz
-0.1 dB cutoff frequency................. 22.6 Hz
AI flatness........................................... ±0.08 dB, gain
≥0
dB,
20 Hz to 92.2 kHz
AI dynamic range ................................ 118 dBFS, 0 dB gain, 51.2 kS/s
THD, balanced source......................... -107 dBc up to 20 kHz,
-104 dBc up to 92.2 kHz
Crosstalk (channel separation) ........... -138 dB at 1 kHz
AI interchannel gain mismatch........... 0.003 dB up to 92.2 kHz
Internal Frequency Timebase Characteristics
Accuracy.............................................. ±20 ppm, over operating
temperature range
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24-Bit, 204.8 kS/s Dynamic Signal Acquisition and Generation
Triggers
Analog Trigger
Source ................................................. AI0, AI1
Level .................................................... ±full-scale
Slope ................................................... Positive or negative
(software-selectable)
Resolution ........................................... 24 bits
Hysteresis............................................ Programmable
Digital Trigger
Compatibility .......................................
Polarity ................................................
Pulse width .........................................
Source .................................................
5 V TTL
Rising or falling edge
10 ns minimum
SMB (PFIO), PXI trigger bus,
RTSI bus
Certifications and Compliances
CE Mark Compliance
For a complete listing of all NI 446x specifications, please visit
ni.com/soundandvibration.
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at
ni.com
or
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