NI SCXI-1124

Description

3HNE08250-1 DCS
ABB 3HNA006147-001
3HNE06225-1/02 ABB DCS
ABB 3HNE05036-1
ABB 3HNA006149-001 DCS
3HNE05034-1 DCS
3HNE00413-1

NI SCXI-1124: Programmable Signal Conditioning Module with Simultaneous Sampling

Product Description

The NI SCXI-1124 is a versatile, high-performance programmable signal conditioning module for the National Instruments SCXI (Signal Conditioning eXtensions for Instrumentation) platform. This module is designed to condition and isolate low-level analog signals from sensors like thermocouples, RTDs (Resistance Temperature Detectors), and strain gauges before they are digitized by a data acquisition (DAQ) device. The NI SCXI-1124 provides critical amplification, filtering, and isolation to ensure accurate and reliable measurements in electrically noisy industrial and laboratory environments. A key feature of the NI SCXI-1124 is its ability to perform simultaneous sampling across its channels, which is essential for applications requiring precise timing relationships between multiple signals. For engineers building high-accuracy measurement and automated test systems, the NI SCXI-1124 is a fundamental component for sensor interfacing. Complete specifications for the NI SCXI-1124 are available in the official NI product documentation.

Product Parameters

• Product Type: Programmable Signal Conditioning Module
• Manufacturer Series: National Instruments SCXI
• Module Designation: SCXI-1124
• Form Factor: SCXI module for use in an SCXI chassis (e.g., SCXI-1000, SCXI-1001).
• Number of Channels: 8 differential analog input channels.
• Input Signal Compatibility: Configurable for a wide range of sensors:
  • Thermocouples (Types J, K, T, E, N, B, R, S)
  • 2-, 3-, and 4-wire RTDs (100 Ω platinum, 120 Ω nickel, etc.)
  • Strain gauges (quarter-, half-, and full-bridge)
  • Voltage inputs (±50 mV to ±10 V ranges)
• Sampling Mode: Simultaneous sampling on all 8 channels (via independent analog-to-digital converters per channel).
• Isolation: 250 Vrms channel-to-channel and channel-to-bus isolation for safety and noise rejection.
• Excitation: Provides programmable current and voltage excitation for RTDs and strain gauges.
• Filtering: Programmable low-pass anti-aliasing filters.
• Gain: Software-selectable gains (1 to 2000).
• Connection: Front-panel screw terminals or connection via an SCXI terminal block.
• Compatibility: Interfaces with NI DAQ devices (e.g., PCI/PXI/PCMCIA) via the SCXI bus.

Advantages and Features

• Simultaneous Sampling: This is the defining feature of the NI SCXI-1124. It eliminates channel-to-channel phase shift (skew), which is critical for vibration analysis, multi-axis strain measurement, and power quality analysis where the timing relationship between signals is as important as the signals themselves.
• High Channel Density & Flexibility: Eight isolated channels in one module that can be individually configured for different sensor types, providing a compact and versatile solution for mixed-measurement applications.
• Excellent Signal Integrity: High isolation and programmable filtering protect low-level sensor signals from ground loops and electromagnetic interference, ensuring measurement accuracy.
• Software-Programmable Configuration: All settings (sensor type, excitation, filter, gain) are configured in software (NI-DAQmx), allowing for rapid system reconfiguration without physical hardware changes.
• Scalable System Architecture: Multiple NI SCXI-1124 modules can be installed in a single SCXI chassis, which can be controlled by a single DAQ device, creating large, synchronized measurement systems.
• Integrated Excitation: Built-in excitation sources simplify wiring and ensure proper operation of RTDs and strain gauge bridges.

Application Cases in Application Fields

• Structural & Mechanical Test: Simultaneously measuring strain from multiple gauges on a test article (e.g., an aircraft wing, automotive chassis) under dynamic load to analyze stress distribution.
• Power Quality & Electrical Testing: Measuring three-phase voltage and current waveforms simultaneously to calculate power, harmonic distortion, and phase relationships.
• Temperature Profiling: Monitoring multiple thermocouples or RTDs distributed across a thermal chamber, engine block, or chemical reactor to map temperature gradients in real time.
• Aerospace & Defense: Conditioning signals from multiple transducers in flight test or hardware-in-the-loop (HIL) simulations where signal timing is critical.
• Research & Development: High-accuracy, multi-channel data logging for physics experiments, material science, and prototype validation.

Comparison with Competing Products

The NI SCXI-1124 competes with other modular signal conditioning systems from vendors like Dewesoft, HBM, and Keysight. Its primary distinction is its deep integration with the overall NI ecosystem (LabVIEW, NI-DAQmx, PXI). Compared to using individual signal conditioners for each sensor, the SCXI-1124 offers a more integrated, software-configurable, and space-efficient solution. The key differentiator from most other SCXI or standard multiplexed DAQ modules is its simultaneous sampling capability. A standard multiplexed input module scans channels sequentially, introducing microsecond delays between channels; the NI SCXI-1124 captures all channels at the exact same instant.

Selection Suggestions and Precautions

1. System Requirements: The NI SCXI-1124 requires an SCXI chassis for power and communication, and a compatible NI DAQ device (e.g., a PCI-6221, PXIe-6363) to act as the controller. It is not a standalone USB device.
2. Simultaneous Sampling Need: Only select the NI SCXI-1124 if your application requires true simultaneous sampling. For slowly changing signals (like most temperature trends), a more cost-effective multiplexed SCXI module (e.g., SCXI-1102) is sufficient.
3. Sensor Configuration & Wiring: Meticulous attention to wiring and software configuration is required. For example, a 4-wire RTD must be wired correctly to the specified terminals to use the module’s 4-wire measurement capability and eliminate lead resistance error.
4. Chassis and Controller Compatibility: Verify that your SCXI chassis model supports the SCXI-1124 and that your DAQ controller has the necessary digital lines for the SCXI bus. Consult the NI compatibility documents.
5. Software Dependency: Full functionality requires NI-DAQmx driver software and a programming environment like LabVIEW, LabWindows/CVI, or measurement software that supports NI-DAQmx.