National Instruments SCXI-1328 High-Accuracy Isothermal Terminal Block

The NI SCXI 1328 (Part Number: 777687-28) has 18 screw terminals to connect to the SCXI-1120, SCXI-1120D, SCXI-1121, SCXI-1125, and SCXI-1126 modules. Of the 18 screw terminals, a single pair attaches to the SCXI chassis ground. For the SCXI-1120/D, SCXI-1125, and SCXI-1126, the other eight pairs of screw terminals are utilized for signal connection to the eight module inputs. However, for the SCXI-1121, four pairs of screw terminals are used for the four module inputs and four pairs are used for the module excitation channels. The SCXI-1328 has a maximum field wire gauge of 26 to 14 AWG. The NI SCXI-1328 has DC coupling, 0.5 °C accuracy at 15 to 35 ˚C, and 0.9 °C at 0 to 15 ˚C and 35 to 55 ˚C.

The SCXI 1328 Shielded Terminal Block comes equipped with a high-precision thermistor for accurate cold-junction compensation, along with an aluminum isothermal plate to reduce the temperature gradients across the screw terminals when the user completes measurements with thermocouples. The NI SCXI 1328 has an onboard temperature sensor, which measures ambient temperature on the interior of the Terminal Block. If the user is measuring temperatures with thermocouples, then they can acquire a temperature from the onboard temperature sensor which can be utilized for cold-junction compensation. To change the voltage reading to a temperature, the user can utilize a thermistor conversion equation. If the user is running LabVIEW, they can use the Convert Thermistor VI. If the user is running NI-DAQ, they can use the Thermistor convert function call. The SCXI-1328 can be performance verified using the Fluke 5700A and the NI 4060 or HP 34401A. It has a maximum working voltage of 300 Vrms (for both channel-to-ground and channel-to-channel connections).

The NI device weighs 7 oz, and measures 7.0 x 3.125 x 1.2 in. in physical dimensions. It has a recommended operating temperature range of 0 to 50 °C, a storage temperature range of –20 to 70 °C, and a noncondensing humidity range of 5 to 90% RH.

SCXI-1328 Obsolete Status has been announced by National Instruments, but the Terminal Block will still be available for purchase and repairs by Apex Waves.