The NI SCXI-1303 is a 32-channel isothermal terminal block designed as a shielded accessory for National Instruments SCXI-1100 and SCXI-1102/B/C modules. It provides differential analog and digital signal connectivity for precision data acquisition systems, with specialized support for thermocouple temperature measurements. The isothermal copper plane construction and integrated high-accuracy thermistor cold-junction sensor minimize thermal gradients across terminals, delivering enhanced measurement accuracy in temperature-critical applications.
Technical Specifications
• Channels: 32 differential input channels
• Terminal Configuration: 78 screw terminals total—32 pairs for differential inputs, 1 pair for chassis ground, 3 dedicated terminals for module OUTPUT, AOREF, and SCXIbus GUARD
• Cold-Junction Compensation: Integrated thermistor temperature sensor (0 to 55 °C operating range)
– Accuracy: ±0.5 °C (15–35 °C), ±0.9 °C (0–15 °C and 35–55 °C)
– Repeatability: 0.2 °C (15–35 °C)
– Output voltage: 1.91 to 0.58 V (0–55 °C)
• Bias Resistors: User-replaceable, configurable as 10 Ω (SCXI-1100) or 10 MΩ (SCXI-1102/B/C factory-installed)
• Open Thermocouple Detection: Integrated circuit applies +5 V to saturate module amplifier output at positive rail
– Key Features
• Isothermal construction minimizes errors from thermal gradients
• High-accuracy cold-junction compensation for thermocouple applications
• 10 MΩ bias resistors support floating or grounded thermocouples with ~2.5 VDC common-mode voltage (SCXI-1102/B/C)
• 10 Ω bias resistors reduce common-mode voltage to near 0 VDC (SCXI-1100)
• Integrated signal ground referencing capability
• Open thermocouple detection with automatic amplifier saturation
– Typical Applications
• Precision thermocouple temperature measurement and cold-junction compensation
• High-accuracy analog signal acquisition in temperature-sensitive systems
• Multi-channel data logging with built-in thermal error correction
– Compatibility & Integration
Mounts directly to SCXI-1100 and SCXI-1102/B/C module fronts via front connector and thumbscrew fasteners. Terminal block configuration supports mixed signal types—analog differential inputs, power references, and bus guard connections—within a single 32-channel interface.
