NI SCXI-1326

The NI SCXI-1326 is a high-density, 68-pin shielded connector terminal block designed for use with specific National Instruments SCXI modules, most notably the NI SCXI-1125 and other modules requiring a direct, multi-channel interface to a high-pin-count connector. This terminal block serves as a robust and organized wiring interface, converting the module’s dense 68-pin connector into individual screw terminals for field wiring. The NI SCXI-1326 is engineered to maintain signal integrity by providing a shielded connection path and designated ground points. For comprehensive technical specifications, pinout diagrams, and connection guides, the essential resource is the official National Instruments product page for the NI SCXI-1326. Implementing the SCXI-1326 terminal block is essential for creating reliable, professional-grade connections in multi-channel data acquisition systems where maintaining signal fidelity and simplifying wiring are paramount. Its design is crucial for applications utilizing the full channel count of high-performance conditioning modules.

Product Parameters

• Manufacturer / Brand: National Instruments (NI).
• Series: SCXI (Signal Conditioning Platform).
• Model: SCXI-1326 – 68-Pin Shielded Connector Terminal Block.
• Function: Wiring Interface / Terminal Block for 68-pin SCXI modules.
• Primary Compatibility: Designed for use with the NI SCXI-1125 32-Channel Isolated Analog Input Module. May also be compatible with other SCXI modules featuring a 68-pin front connector.
• Connector: Interfaces with the module’s 68-pin, high-density D-sub (HD68) connector.
• Terminals: Provides 96 screw terminals to break out all signals from the 68-pin connector, including analog inputs, digital I/O, timing signals, and grounds.
• Shielding: Incorporates a shielded metal shell that mates with the module’s connector, providing continuous EMI/RFI protection for sensitive analog signals.
• Grounding: Includes dedicated terminals for analog ground (AI GND), digital ground (DGND), and shield ground.
• Form Factor: A rigid, shielded enclosure that plugs directly into the front of the compatible SCXI module.
• Passive Device: Contains no active electronics; it is a wiring interface and shielding mechanism.

Advantages and Features

• Professional High-Density Interface: Effectively manages the complexity of connecting 32 differential analog channels (or other signal configurations) by providing a clean, labeled, screw-terminal interface for every pin.
• Superior Signal Integrity: The integrated shielded shell provides excellent protection against electromagnetic interference, which is critical for maintaining the accuracy of low-level analog signals, especially in noisy industrial environments.
• Simplified System Wiring: Eliminates the need for custom, hard-to-manage cables by providing a direct, organized point for field wiring, reducing installation time and potential errors.
• Robust and Reliable Connections: Screw terminals ensure secure, vibration-resistant connections, which are more reliable than repeated plug/unplug cycles on the module’s native high-density connector.
• Clear Signal Identification: Terminals are clearly numbered and often labeled (e.g., AI GND, +5V), simplifying the wiring process and troubleshooting.

Application Cases in Industry

• Structural Test and Measurement: The NI SCXI-1326 is used to connect a large array of strain gauge bridges (e.g., 32 channels) from an aircraft wing or bridge component to the SCXI-1125 module for stress analysis.
• High-Channel-Count Data Acquisition: In an automotive test cell, it interfaces dozens of low-voltage analog sensors (pressure, displacement) to the SCXI system for comprehensive performance monitoring.
• Precision Laboratory Measurements: Provides the connection point for multiple precision voltage sources or transducer outputs in a calibrated measurement setup, where shielded connections are mandatory.
• Power Electronics Monitoring: Used to connect multiple isolated voltage and current probe outputs to the data acquisition system for switching loss analysis and efficiency measurements in inverter testing.
• Environmental Chamber Monitoring: Connects a multitude of sensor types (requiring various analog input configurations) from a large climatic chamber to a centralized DAQ system.

Comparison with Competing Products

Competing products are other high-pin-count terminal blocks from data acquisition vendors or generic shielded D-sub to terminal block adapters. The NI SCXI-1326 differentiates itself through its official, optimized design for NI SCXI hardware. Compared to a generic adapter, the SCXI-1326 guarantees correct pin mapping, mechanical fit, and maintains the shielding integrity designed into the SCXI system. While a competitor like Keysight has similar accessories, they are not cross-compatible. The SCXI-1326‘s primary advantage is its plug-and-play reliability and guaranteed performance within the NI ecosystem, ensuring that the high channel isolation and specifications of modules like the SCXI-1125 are not compromised by a poor-quality interface.

Selection Suggestions and Precautions

• Selection Suggestions:
  1. Select the NI SCXI-1326 specifically when using an SCXI-1125 module or another SCXI module that explicitly lists the SCXI-1326 as the compatible terminal block in its datasheet.
  2. Verify the pinout of your specific SCXI module against the SCXI-1326 terminal numbering to ensure correct signal mapping before wiring.
  3. This terminal block is ideal for applications where all 32 (or most) channels of the SCXI-1125 will be used, as it provides access to every pin.
• Precautions:
  1. Pinout Verification is Critical: The 68-pin connector carries analog inputs, digital I/O, power, and grounds. Incorrect wiring can damage the module. Always use the official NI pinout diagram for your specific module and the SCXI-1326.
  2. Shield Grounding: Connect the shield terminal of the SCXI-1326 to a clean earth ground point as part of a single-point grounding strategy. Improper shield grounding can create ground loops and introduce noise.
  3. Wire Management: With 96 terminals, cable organization is crucial. Use cable ties and labels meticulously to prevent shorts and to make future maintenance possible.
  4. Torque Specifications: Adhere to the recommended torque for the screw terminals. Over-tightening can damage the terminal block, while under-tightening leads to high-resistance connections and thermal drift.
  5. Handling and Compatibility: Do not force the terminal block onto the module. Ensure it is the correct model for your hardware revision. Source the NI SCXI-1326 from authorized NI distributors to ensure you receive a genuine part with proper shielding and build quality. Using a counterfeit or poorly made adapter risks signal integrity and module safety.