National Instruments 777687-17 Terminal Block 

The National Instruments part number 777687-17 (model name SCXI-1317), is a front-mounting terminal block specifically engineered for use with the SCXI-1521 and SCXI-1521B quarter-bridge strain gauge input modules. This robust terminal block offers 24 channels, each equipped with three screw terminals for precise and stable connections: excitation (+), analog input, and quarter-bridge. Designed with precision and accuracy in mind, the 777687-17 ensures shielded signal connections, minimizing the risk of noise interference and signal degradation, making it ideal for sensitive strain gauge measurements.

The 777687-17 is designed for easy integration into SCXI systems, boasting autodetection capabilities via software, which streamlines the setup process. This feature allows users to quickly and efficiently configure their data acquisition systems without manual input, enhancing productivity and reducing the margin for error.

To connect signals to the 777687-17, users must follow the following process: unscrew and remove the terminal block’s top cover, loosen the strain-relief bar, and then strip the insulation from the signal wires (ensuring the stripped section is no longer than 0.28 inches). Afterward, the wires should be threaded through the strain-relief opening, with additional insulation or padding added if necessary. Once inserted into the terminals, ensure no bare wire extends beyond the screw terminals to prevent short circuits and potential circuit failures.

Operationally, the 777687-17 requires specific hardware to function effectively. This includes an SCXI-1521 or SCXI-1521B module, an SCXI or PXI/SCXI combination chassis, appropriate cabling, a cable adapter, and quarter-bridge strain gauges tailored to the application at hand. The terminal block also offers a grounding option; when working with 2- or 3-wire strain gauges that are shielded, the shield can be connected to the GND link on the 777687-17, ensuring a stable and noise-free measurement environment.

Despite its robust design and high performance, the 777687-17, like many legacy National Instruments products, has been declared obsolete by the manufacturer. However, it remains available for purchase, along with repair services, through Apex Waves, ensuring continued support for legacy systems that rely on this vital component. Apex Waves specializes in providing high-quality, factory-calibrated legacy test equipment, ensuring your systems continue to perform optimally even with discontinued hardware.