Product Overview
The National Instruments NI 9231 is an eight channel sound and vibration input module for CompactDAQ and CompactRIO systems. It is designed for measurement of accelerometers, microphones, and other IEPE sensors. The module provides 24 bit resolution and integrated IEPE signal conditioning for acoustic and vibration test applications.
The NI 9231 is part of the NI C Series platform. It can be combined with analog output, digital I/O, counter, and communication modules in a compatible chassis. The module is used in machine condition monitoring, modal analysis, product noise testing, and structural dynamic measurement.
IEPE Signal Conditioning
The NI 9231 includes integrated IEPE conditioning for compatible sensors. IEPE sensors require excitation and AC coupling for many sound and vibration measurements. Integrated conditioning reduces external hardware and simplifies wiring in multi channel systems. Engineers can configure excitation and coupling settings through software.
The module provides 24 bit resolution for low level dynamic signals. It includes anti alias filtering and low noise input circuitry to support frequency domain analysis. Proper sensor mounting, cabling, and grounding are important for accurate acoustic and vibration measurements.
Sampling and Synchronization
The NI 9231 supports high resolution sampling for dynamic signal acquisition. The module can be synchronized with other C Series modules through the chassis timing resources. This allows sound and vibration data to be correlated with speed, force, temperature, and other sensor signals in the same system.
Hardware timed acquisition and triggering help align measurements with external events. The module is suitable for rotating machinery test, impact testing, and structural response measurement. Data can be streamed to the host for logging and analysis, including spectral analysis and order tracking.
Software and System Integration
The NI 9231 is supported by NI-DAQmx driver software. It can be programmed with LabVIEW, LabWindows/CVI, Measurement Studio, and other NI-DAQmx compatible development environments. Engineers can configure IEPE excitation, input ranges, sampling rates, and triggering through standard software tools. The module can also use TEDS with compatible sensors to simplify sensor identification.
In a CompactDAQ system, the NI 9231 is used for portable and bench top sound and vibration measurement. In a CompactRIO system, it can be part of an embedded monitoring system that detects machine vibration and triggers control actions. The module supports synchronization with other C Series modules for mixed signal test.
Typical Applications
Accelerometer and microphone measurement
Machine condition monitoring and vibration analysis
Modal and structural dynamic testing
Product noise and vibration validation
CompactDAQ acoustic measurement systems
CompactRIO embedded vibration monitoring
The NI 9231 provides eight IEPE sound and vibration input channels with 24 bit resolution for CompactDAQ and CompactRIO systems. Its integrated IEPE conditioning and C Series integration make it a practical module for multi channel acoustic and vibration measurement.
