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National Instruments 777687-28 High-Accuracy Terminal Block 

National Instruments part number 777687-28 is an identifying part number for the SCXI-1328, a High-Accuracy Isothermal Terminal Block with 18 Screw Terminals, DC Coupling and SH32-32-A cabling. The NI 777687-28 Shielded Terminal Block includes a high-precision thermistor for accurate cold-junction compensation and an aluminum isothermal plate to minimize temperature variations across the screw terminals during thermocouple measurements. It also features an onboard temperature sensor that monitors the ambient temperature inside the Terminal Block. 

When measuring temperatures with thermocouples, users can use this onboard sensor for cold-junction compensation. To convert voltage readings into temperature values, users can apply a thermistor conversion equation. In LabVIEW, they can utilize the Convert Thermistor VI, while in NI-DAQ, they can employ the Thermistor convert function call. It features 18 screw terminals designed specifically for connecting to SCXI-1120, SCXI-1120D, SCXI-1121, SCXI-1125, and SCXI-1126 modules. Within these terminals, one pair is dedicated to connecting to the SCXI chassis ground. 

Depending on the module type, the remaining terminals are allocated differently: for SCXI-1120/D, SCXI-1125, and SCXI-1126, eight pairs are used for signal connections to the module inputs. In contrast, for SCXI-1121, four pairs of terminals serve the module inputs, and the other four pairs are used for the module's excitation channels. The NI 777687-28 can undergo performance verification using equipment such as the Fluke 5700A, NI 4060, or HP 34401A. It supports a maximum working voltage of 300 Vrms, applicable to both channel-to-ground and channel-to-channel connections.