16 simultaneous analog inputs 24-bit resolution 204.8 kS/s maximum sampling rate 114 dB dynamic range +10, +20, and +30 dB gains	±0.316, 1, 3.16, and 10 V input ranges Antialiasing filters TEDS read/write IEPE – 4 mA (software-configurable) AC-coupled (0.5 Hz)

Overview

NI PXI-449x and PXIe-449x high-accuracy data acquisition modules are specifically designed for sound and vibration applications. With up to sixteen 24-bit analog inputs per module and IEPE constant current signal conditioning, NI 449x modules are ideal for making precision measurements with microphones, accelerometers, and other transducers that have large dynamic ranges. The modules deliver up to 114 dB of dynamic range and simultaneous sampling on all 16 channels at rates up to 204.8 kS/s. In addition, the modules include built-in antialiasing filters that automatically adjust to your sampling rate and feature software-selectable input gains up to 30 dB. Common applications for NI 449x modules include in-vehicle acoustic test; noise, vibration, and harshness (NVH) analysis; large microphone arrays; and dynamic structural test. These modules are compatible with NI Sound and Vibration Measurement Suite analysis software to complete your application with a variety of time and frequency measurements including octave and order analysis.

Requirements and Compatibility

OS Information Real-Time OS Windows 2000/XP Windows 7 Windows Vista

Application and Technology

Analog Input Operation 

Each input signal is simultaneously buffered, amplified, analog filtered, and sampled by a 24-bit delta-sigma analog-to-digital converter (ADC) that performs digital filtering with a cutoff frequency that automatically adjusts to a software-programmable sampling rate. The high resolution provides the necessary accuracy to make NI 449x modules well-suited for audio and vibration analysis applications. A programmable gain amplifier stage on the inputs offers gain selection from 0 to +30 dB in 10 dB steps. In addition, the modules include the capability to read and write to transducer electronic data sheet (TEDS) Class 1 smart sensors as well as operate with IEPE constant current on or off as selected in software.

Figure 1. FFT of -1 dBFS, 1 kHz Tone Acquired at 204.8 kS/s and 0 dB Gain Using the NI PXI-4498 (65,536 Samples With 10 RMS Averages Using the 7-Term Blackman-Harris Window)

 

NI 449x modules use a method of A/D conversion known as delta-sigma modulation. With this technology, input signals are oversampled or sampled at many times the chosen data rate and then applied to a digital filter. NI 449x modules incorporate delta-sigma modulating ADCs, resulting in excellent phase linearity while maintaining low noise and distortion. In addition, this class of ADCs makes these modules immune to the differential nonlinearity (DNL) distortion associated with conventional data acquisition devices.

Table 1. NI PXIe-449x and PXI-449x Dynamic Signal Acquisition Selection Guide

Antialiasing

All of the input channels use both analog and digital filters implemented in hardware to prevent aliasing. Signals are first passed through fixed analog filters to remove any signals with frequency components beyond the range of the ADCs. Then digital antialiasing filters automatically adjust their cutoff frequencies to remove any frequency components above half the programmed sampling rate. This specialized architecture means that you do not need to add more external filters to prevent aliasing.

PXI Versus PXI Express

PXI Express technology is the latest addition to the PXI platform. The PXI Express Specification integrates PCI Express signaling into the PXI standard, which increases backplane bandwidth from 132 MB/s to 6 GB/s, a 45 times improvement. It also enhances PXI timing and synchronization features by incorporating a 100 MHz differential reference clock and differential triggers. With PXI Express, you can easily synchronize 17 NI PXIe-449x modules in an 18-slot PXI Express chassis and simultaneously sample 272 channels at full bandwidth. 

Triggering 

NI 449x modules feature analog and digital signal triggering for acquisition with two modes of operation. Trigger sources can come from any analog input channel, the external digital trigger input, or the PXI trigger bus. The external digital trigger, which is 5 V TTL/CMOS-compatible, is activated by a choice of rising or falling edge. When used in the start trigger mode, an NI 449x acquires signals only after the trigger condition has occurred. In the reference trigger mode, the device can acquire signals before and after the trigger condition occurs. Triggering is often used in applications with transient signals. For example, when measuring vibrations resulting from striking a mechanical structure with a hammer, acquisition of accelerometer signals is triggered by the hammer impact.

 

Signal Connectivity

InfiniBand Overview

NI 449x modules use two 4X InfiniBand connectors, AI0-7 and AI8-15, with each connector carrying eight analog input channels. The 4X InfiniBand is widely used in high-performance computing applications because it provides excellent signal integrity with a shield plate between signal connection pairs, reducing crosstalk between inputs.

Figure 2. SHB4X-8BNC Shielded InfiniBand to BNC Cable

Direct to BNC Connectivity 

A shielded InfiniBand to BNC cable, the NI SHB4X-8BNC is available in a two pack for direct connectivity to NI 449x modules. Each cable has a 4X InfiniBand connector on one end and eight BNC jack inputs on the other end.

Figure 3. NI BNC-2144 Rack-Mount Accessory

Rack-Mount BNC

The NI BNC-2144 is a signal connector accessory for NI PXIe-449x and PXI-449x modules. It has 32 BNC jack inputs on the front and four 4X InfiniBand connectors on the rear for use with up to two NI 449x modules. You can mount it on a standard 19 in. rack for simple, direct connections to accelerometers and microphones.

Software

Analysis Software

NI 449x modules are well-suited for noise and vibration analysis applications, which you can specifically address with the NI Sound and Vibration Measurement Suite. The suite has two components – the NI Sound and Vibration Assistant and LabVIEW analysis VIs (functions) for power spectra, frequency response (FRF), fractional octave analysis, sound level measurements, order spectra, order maps, order extraction, sensor calibration, human vibration filters, and torsional vibration.

Sound and Vibration Assistant

Figure 4. The Sound and Vibration Assistant combines live data capture, the ability to modify analysis settings dynamically, and data logging with an easy drag-and-drop user interface.

 

The Sound and Vibration Assistant is interactive software designed to simplify the process of acquiring and analyzing noise and vibration signals by offering the following:

• A drag-and-drop, interactive analysis and acquisition environment
• Rapid measurement configuration
• Extended functionality through LabVIEW

 

Software Recommendations

LabVIEW Professional Development System for Windows	Advanced software tools for large project development Automatic code generation using DAQ Assistant and Instrument I/O Assistant Tight integration with a wide range of hardware Advanced measurement analysis and digital signal processing Open connectivity with DLLs, ActiveX, and .NET objects Capability to build DLLs, executables, and MSI installers	NI LabVIEW Real-Time Module	Design deterministic real-time applications with LabVIEW graphical programming Download to dedicated NI or third-party hardware for reliable execution and a wide selection of I/O Take advantage of built-in PID control, signal processing, and analysis functions Automatically take advantage of multicore CPUs or set processor affinity manually Includes real-time operating system (RTOS), development and debugging support, and board support Purchase individually or as part of an NI Developer Suite bundle
NI Sound and Vibration Toolkit	Stand-alone configuration-based analysis and data logging with the Sound and Vibration Assistant AES17-compliant audio filter signal processing Easy-to-use power spectrum, swept sine, and octave analysis steps Sound level with A-, B-, or C-weighting and vibration level with integration Audio measurements including THD, SNR, SINAD, and swept-sine analysis Universal File Format (UFF58) file I/O support	NI Sound and Vibration Measurement Suite	Minimize development time with ready-to-run application examples Get started quickly with the Sound and Vibration Assistant (LabVIEW not required) Build custom data acquisition systems faster than ever with DAQ configuration XControl Avoid the expense of verification with NI ANSI- and IEC-compliant octave and sound-quality analysis Decrease test time with parallel processing

Support and Services

System Assurance Programs

NI system assurance programs are designed to make it even easier for you to own an NI system. These programs include configuration and deployment services for your NI PXI, CompactRIO, or Compact FieldPoint system. The NI Basic System Assurance Program provides a simple integration test and ensures that your system is delivered completely assembled in one box. When you configure your system with the NI Standard System Assurance Program, you can select from available NI system driver sets and application development environments to create customized, reorderable software configurations. Your system arrives fully assembled and tested in one box with your software preinstalled. When you order your system with the standard program, you also receive system-specific documentation including a bill of materials, an integration test report, a recommended maintenance plan, and frequently asked question documents. Finally, the standard program reduces the total cost of owning an NI system by providing three years of warranty coverage and calibration service. Use the online product advisors at ni.com/advisor to find a system assurance program to meet your needs.

Calibration

NI measurement hardware is calibrated to ensure measurement accuracy and verify that the device meets its published specifications. To ensure the ongoing accuracy of your measurement hardware, NI offers basic or detailed recalibration service that provides ongoing ISO 9001 audit compliance and confidence in your measurements. To learn more about NI calibration services or to locate a qualified service center near you, contact your local sales office or visit ni.com/calibration.

Technical Support

Get answers to your technical questions using the following National Instruments resources.

• Support - Visit ni.com/support to access the NI KnowledgeBase, example programs, and tutorials or to contact our applications engineers who are located in NI sales offices around the world and speak the local language.
• Discussion Forums - Visit forums.ni.com for a diverse set of discussion boards on topics you care about.
• Online Community - Visit community.ni.com to find, contribute, or collaborate on customer-contributed technical content with users like you.

Repair

While you may never need your hardware repaired, NI understands that unexpected events may lead to necessary repairs. NI offers repair services performed by highly trained technicians who quickly return your device with the guarantee that it will perform to factory specifications. For more information, visit ni.com/repair.

Training and Certifications

The NI training and certification program delivers the fastest, most certain route to increased proficiency and productivity using NI software and hardware. Training builds the skills to more efficiently develop robust, maintainable applications, while certification validates your knowledge and ability.

• Classroom training in cities worldwide - the most comprehensive hands-on training taught by engineers.
• On-site training at your facility - an excellent option to train multiple employees at the same time.
• Online instructor-led training - lower-cost, remote training if classroom or on-site courses are not possible.
• Course kits - lowest-cost, self-paced training that you can use as reference guides.
• Training memberships and training credits - to buy now and schedule training later.

Visit ni.com/training for more information.

Extended Warranty

NI offers options for extending the standard product warranty to meet the life-cycle requirements of your project. In addition, because NI understands that your requirements may change, the extended warranty is flexible in length and easily renewed. For more information, visit ni.com/warranty.

OEM

NI offers design-in consulting and product integration assistance if you need NI products for OEM applications. For information about special pricing and services for OEM customers, visit ni.com/oem.

Alliance

Our Professional Services Team is comprised of NI applications engineers, NI Consulting Services, and a worldwide National Instruments Alliance Partner program of more than 700 independent consultants and integrators. Services range from start-up assistance to turnkey system integration. Visit ni.com/alliance.

Detailed Specifications

This document lists specifications for the NI 4492, NI 4495, NI 4496, NI 4497, NI 4498, and NI 4499 Dynamic Signal Acquisition (DSA) analog input devices. These specifications are typical at 25 °C unless otherwise stated. The operating range for the NI 449x is 0 to 55 °C. All specifications are subject to change without notice. Visit ni.com/manuals for the most current specifications and product documentation.
Input Characteristics
Number of simultaneously sampled input channels
16		NI 4495/4496/4497 NI 4498/4499
8		NI 4492
Input configuration		Pseudodifferential (50 Ω between negative input and chassis ground)
Input coupling
DC only		NI 4495
AC only		NI 4496/4498
AC/DC		NI 4492/4497/4499
A/D converter (ADC) resolution		24 bits
ADC type		Delta-sigma
Sample rates (  ƒs), samples-per-second (S/s)		100 S/s to 204.8 kS/s in 181.9 μS/s increments, maximum
FIFO buffer size		4,095 samples
Data transfers		Direct memory access (DMA)
Maximum Working Voltage

Overvoltage Protection

Signal Range

Transfer Characteristics
AI Offset (residual DC) 1		±2 mV max
AI Gain amplitude accuracy
1 kHz input tone 1		0.1 dB max
Over operating temperature range		±0.2 dB max
Amplifier Characteristics
Impedance

Common-Mode Rejection Ratio (CMRR)
Input frequency < 20 kHz 2		40 dB
Dynamic Characteristics
Bandwidth and Alias Rejection

Magnitude Response of AC Coupling Circuit (1 Hz to 1 kHz)
Phase Response of AC Coupling Circuit (1 Hz to 1 kHz)
AC Coupling  3
–3 dB cutoff frequency		0.5 Hz
– 0.1 dB cutoff frequency		3.3 Hz
ADC Filter Delay

Flatness

Spectral Noise Density
NI 4492/4495/4496/4497 input voltage noise density		14 nV/ at 20 dB gain, 1 kHz
NI 4498/4499 input voltage noise density		7 nV/ at 30 dB gain, 1 kHz
30 dB Gain Spectral Noise Density of the NI 4498 with 50 Ω at Input
Idle Channel Noise

Spurious Free Dynamic Range (SFDR) (NI 4492/4495/4496/4499)

Spurious Free Dynamic Range (SFDR) (NI 4498/4499)

SFDR 51.2 kS/s (–1 dBFS, 0 dB Gain, 1 kHz Sine Wave Input)

SFDR 102.4 kS/s (–1 dBFS, 0 dB Gain, 1 kHz Sine Wave Input)

SFDR 204.8 kS/s (–1 dBFS, 0 dB Gain, 1 kHz Sine Wave Input)

Dynamic Range (NI 4492/4495/4496/4497)

Dynamic Range (NI 4498/4499)

Total Harmonic Distortion Plus Noise (THD+N) (NI 4492/4495/4496/4497)

THD+N (NI 4498/4499)

Intermodulation Distortion (IMD)

Crosstalk

Interchannel Gain Mismatch
Gain mismatch		0.02 dB at 1 kHz

Interchannel Phase Mismatch
Phase mismatch		0.01 deg at 1 kHz

Note All gain and phase mismatch specifications are for the same device and are not applicable between different NI 449x devices.

Phase Linearity

Onboard Calibration Reference
DC level		5.000 V ±2.5 mV
Temperature coefficient		±5 ppm / °C max
Long-term stability		±15 ppm /
IEPE Excitation
Note NI 4495 does not support IEPE Excitation.
Current		0 or 4 mA, ±10% each channel independently software selectable
Compliance		24 V
Note Use the following equation to make sure that your configuration meets the IEPE compliance voltage range. V common-mode + V bias ± V full-scale must be 1 to 24 V, where V common-mode is the common-mode voltage seen by the input channel, V bias is the DC bias voltage of the sensor, and V full-scale is the AC full-scale voltage of the sensor.
IEPE open		Software readable 4
IEPE short		Software readable 4
Channel input impedance with IEPE enabled		> 250 kΩ at 1 kHz
Current noise		20 pA/
Parallel capacitance		TBD
Transducer Electronic Data Sheet (TEDS) Support
All device inputs (except the NI 4495) support Transducer Electronic Data Sheet (TEDS) according to the IEEE 1451 Standard. For more information about TEDS, go to ni.com/info and enter the info code rdteds.
Maximum cable length		100 ft
FFT of –1 dBFS, 1 kHz Tone Acquired at 204.8 kS/s and 0 dB Gain using the NI 4498. 65,536 Samples with 10 RMS Averages using the 7-Term Blackman-Harris Window. Source: Krohn-Hite, Model 4402B.
Internal Frequency Timebase Characteristics
Accuracy		±30 ppm max, over operating temperature range
Aging		5 ppm max/year
Triggers
Analog trigger
Purpose		Start or reference trigger
Source		Any AI
Level		Full scale, programmable
Slope		Positive (rising) or negative (falling), software selectable
Resolution		24 bits
Hysteresis		Programmable
Digital trigger
Purpose		Start or reference trigger
Source		PFI0, PXI_Trig<0..6>
Compatibility		Transistor-transistor logic (5 V TTL)
Polarity		Rising or falling edge
Minimum pulse width		100 ns
General Specifications
Bus Interface
PXI		3.3 V or 5 V signal environment
PXIe		3.3 V diff signal environment
DMA channels		1
Synchronization
PXI		CLK_10
PXIe		CLK_10
Power Requirements

Physical
Dimensions (not including connectors) PXI, PXIe		16 cm × 10 cm (6.3 in. × 3.9 in.) 3U CompactPCI slot
Analog I/O connectors		InfiniBand 4x
Digital trigger connector (PFI 0)		SMB
Weight
PXI		326 g (11.5 oz)
PXIe		323 g (11.4 oz)
PXIe-4492		TBD
Measurement Category 5		I
Caution Do not use the NI 449x for connections to signals or for measurements within Categories II, III, or IV.
Environmental Specifications
Maximum altitude		2,000 m (at 25 °C ambient temperature)
Pollution Degree		2
Indoor use only
Operating Environment
Ambient temperature range		0 to 55 °C (Tested in accordance with IEC-60068-2-1 and IEC-60068-2-2.) 0 to 45 °C when installed in an NI PXI-1000B DC chassis.
Relative humidity range		10 to 90%, noncondensing (Tested in accordance with IEC-60068-2-56.)
Storage Environment
Ambient temperature range		–20 to 70 °C (Tested in accordance with IEC-60068-2-1 and IEC-60068-2-2.)
Relative humidity range		5 to 95%, noncondensing (Tested in accordance with IEC-60068-2-56.)
Shock and Vibration
Operational shock		30 g peak, half-sine, 11 ms pulse (Tested in accordance with IEC-60068-2-27. Test profile developed in accordance with MIL-PRF-28800F.)
Random vibration
Operating		5 to 500 Hz, 0.3 grms
Nonoperating		5 to 500 Hz, 2.4 grms (Tested in accordance with IEC-60068-2-64. Nonoperating test profile exceeds the requirements of MIL-PRF-28800F, Class 3.)
Calibration
Self-calibration		On software command, the device computes gain and offset corrections relative to high-precision internal reference.
Self-calibration interval		Recommended whenever ambient temperature differs from Tcal by more than ±5 °C
External calibration interval		1 year
Warm-up time		15 minutes
Safety Standards
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 61010-1, CSA 61010-1 Note For UL and other safety certifications, refer to the product label or the Online Product Certification section.
Electromagnetic Compatibility
This product meets the requirements of the following EMC standards for electrical equipment for measurement, control, and laboratory use: EN 61326 (IEC 61326): Class A emissions; Basic immunity EN 55011 (CISPR 11): Group 1, Class A emissions AS/NZS CISPR 11: Group 1, Class A emissions FCC 47 CFR Part 15B: Class A emissions ICES-001: Class A emissions Note For EMC declarations and certifications, refer to the Online Product Certification section. Note For EMC compliance, operate this product according to the documentation.
CE Compliance
This product meets the essential requirements of applicable European Directives, as amended for CE marking, as follows: 2006/95/EC; Low-Voltage Directive (safety) 2004/108/EC; Electromagnetic Compatibility Directive (EMC)
Online Product Certification
To obtain product certifications and the DoC for this product, visit ni.com/certification, search by model number or product line, and click the appropriate link in the Certification column.
Environmental Management
NI is committed to designing and manufacturing products in an environmentally responsible manner. NI recognizes that eliminating certain hazardous substances from our products is beneficial not only to the environment but also to NI customers. For additional environmental information, refer to the NI and the Environment Web page at ni.com/environment. This page contains the environmental regulations and directives with which NI complies, as well as other environmental information not included in this document.
Waste Electrical and Electronic Equipment (WEEE)
EU Customers At the end of the product life cycle, all products must be sent to a WEEE recycling center. For more information about WEEE recycling centers, National Instruments WEEE initiatives, and compliance with WEEE Directive 2002/96/EC on Waste Electrical and Electronic Equipment, visit ni.com/environment/weee.htm.