National Instruments 781349-01 Terminal Block for PXI Express Thermocouple Input Module

National Instruments part number 781349-01 is an identifying part number of the TB-4353, a Terminal Block designed for the NI PXIe-4353 PXI Express Thermocouple Input Module. The 781349-01 facilitates screw terminal connectivity for up to 32 thermocouple inputs and includes 8 cold-junction compensation (CJC) channels equipped with NTC thermistors, enhancing CJC accuracy for precise temperature measurements.

The 781349-01 terminal block is engineered for use with the NI PXIe-4353 module, which features a ±80 mV maximum voltage measurement range. To ensure compatibility and prevent incorrect connections, the TB-4353 incorporates keying mechanisms. The terminal block also includes a strain-relief mechanism and tie-wrap holes, offering additional strain relief for connected signal wires. For cold-junction compensation, the TB-4353 integrates 8 thermistors that measure the temperature of adjacent screw terminal junctions, with each thermistor corresponding to a subset of thermocouple channels. This design ensures accurate CJC measurements under varying conditions, making it ideal for high-precision temperature monitoring.

The 781349-01 offers a typical CJC accuracy of 0.20°C at 23°C ±5°C, with a maximum of 0.30°C. Across the full operating temperature range of 0°C to 55°C, it maintains a typical accuracy of 0.35°C with a maximum of 0.45°C, supporting wire gauges up to 14 AWG maximum. With dimensions of 5.10 inches (12.95 cm) in height and 6.02 inches (15.28 cm) in width, the TB-4353 is compact and suitable for indoor use only. It is designed for operation at a maximum altitude of 2,000 meters and meets safety and electromagnetic compatibility standards, including IEC 61010-1 for safety and EN 61326-1 for EMC. The terminal block features 300 Vrms channel-to-earth ground isolation under Measurement Category II and comes with a 1-year calibration interval.