NI SCXI-1141: 8-Channel Wide-Bandwidth Digitizer Module

Product Description

The NI SCXI-1141 is a high-performance signal conditioning and digitizer module from National Instruments (NI) designed for use within the SCXI (Signal Conditioning eXtensions for Instrumentation) platform. Primarily used in high-precision data acquisition (DAQ) and automated test systems rather than traditional real-time PLC control, this module excels at acquiring and conditioning high-frequency analog signals. The NI SCXI-1141 functions as a high-speed front-end, providing programmable gain, anti-aliasing filtering, and analog-to-digital conversion for up to eight simultaneous input channels. It is engineered for applications requiring accurate measurement of dynamic signals such as vibration, acoustics, and transient events. The modular architecture of the SCXI system, centered around components like the NI SCXI-1141, allows for scalable and flexible test and measurement setups.

Product Parameters

• Product Type: Signal Conditioning / Digitizer Module

• Manufacturer: National Instruments (NI)

• Part Number: SCXI-1141

• Platform: SCXI Modular Instrumentation

• Number of Channels: 8 simultaneous sampling channels.

• Input Type: Differential Analog Input.

• Resolution: 14-bit Analog-to-Digital Converter (ADC).

• Maximum Sampling Rate: Up to 1.25 MS/s (Mega Samples per second) aggregate, configurable per channel.

• Input Range: Software-selectable gain (1, 2, 5, 10, 20, 50, 100).

• Bandwidth: 500 kHz bandwidth per channel.

• Connector: Front-panel SMB connectors for signal input.

Advantages and Features

The primary advantage of the NI SCXI-1141 is its combination of high-speed synchronous sampling and sophisticated on-module signal conditioning. Key features include simultaneous sampling on all channels, which is crucial for maintaining phase relationships in multi-channel measurements like modal analysis. Its programmable anti-aliasing filters prevent signal distortion and ensure data integrity. The module offers excellent noise performance and high common-mode voltage rejection, making it suitable for measurements in electrically noisy industrial environments. Integration with the NI-DAQmx driver software and LabVIEW provides a streamlined workflow for configuration, acquisition, and analysis. The modularity of the NI SCXI-1141 allows for easy channel expansion by adding more modules to an SCXI chassis.

Application Cases in Various Fields

This module is used in advanced data acquisition and test systems. In Aerospace and Defense, the NI SCXI-1141 is used for structural health monitoring, flight test data acquisition, and vibration analysis on aircraft components. Within Automotive R&D, it captures data from engine dynamometers, crash tests, and NVH (Noise, Vibration, and Harshness) testing. For Industrial Machinery condition monitoring, it acquires high-frequency vibration signals from bearings and gears for predictive maintenance analysis. It is also employed in Acoustic Testing for product quality control and in University Research Labs for general-purpose dynamic signal measurement.

Comparisons with Competing Products

Unlike standard PLC analog input cards (which are slower and designed for process control), the NI SCXI-1141 competes in the PC-based data acquisition market. Compared to other high-speed DAQ modules from vendors like Keysight or Data Translation, the NI SCXI-1141 is distinguished by its tight integration within the NI ecosystem (SCXI, PXI, LabVIEW), offering a cohesive hardware and software solution. Its simultaneous sampling architecture is a key differentiator from multiplexed DAQ cards, providing superior performance for multi-channel, phase-sensitive measurements. For users committed to the NI platform, the NI SCXI-1141 offers a proven, well-supported path for high-speed analog acquisition.

Selection Suggestions and Precautions

1. System Requirements: The NI SCXI-1141 requires an SCXI chassis for power and communication, and a compatible interface (e.g., an SCXI-1200 series controller module with a DAQ card or a PXI system) to connect to the host computer. Ensure you have the complete system architecture.

2. Signal Compatibility: Verify your signal source characteristics (frequency, amplitude, source impedance) are within the specified input range and bandwidth of the NI SCXI-1141. Use appropriate sensors or transducers.

3. Software Dependency: Configuration and operation are heavily dependent on NI software (NI-DAQmx, LabVIEW, or LabWindows/CVI). Ensure you have the correct driver version and development environment.

4. Sampling Strategy: Plan your sampling rate and filter settings carefully based on the highest frequency component of your signal (Nyquist theorem) to avoid aliasing. The on-board filters of the NI SCXI-1141 are a critical tool for this.

5. Calibration: For precision measurements, factor in the need for periodic calibration of the NI SCXI-1141 module using NI calibration services or procedures to maintain specified accuracy.