The National Instruments SCXI-1112 is an 8-channel thermocouple input module for high-accuracy temperature measurement within SCXI systems. Each channel delivers fixed-gain amplification and precision filtering optimized for thermocouple signals. The module amplifies low-level thermocouple outputs with a gain of 100, then applies individual 3-pole lowpass filters at 2 Hz cutoff to eliminate 60 Hz noise. Cold-junction compensation is performed on each of the eight dedicated sensor channels, while open-thermocouple detection with front-panel LEDs provides instant fault visibility. Auto-zeroing circuitry removes offset voltages, and an onboard reference enables external calibration verification. Input impedance exceeds 1 GΩ under normal operation, ensuring minimal thermocouple loading. The module accepts ±100 mV signals and tolerates overvoltage transients up to ±42 V. Its eight differential input channels multiplex into a single DAQ channel, expanding measurement capacity within compatible systems. Maximum sampling reaches 333 kS/s with nonlinearity held to ±0.005% of full scale.
Technical Specifications
• Input Channels: 8 differential analog inputs; 8 cold-junction sensor channels
• Input Range: ±100 mV
• Gain: 100 (fixed, per channel)
• Filtering: 3-pole lowpass, 2 Hz cutoff per channel
• Bandwidth: 2 Hz
• Maximum Sampling Rate: 333 kS/s
• Input Impedance: >1 GΩ (powered mode); ~10 kΩ (overload or unpowered)
• Overvoltage Protection: ±42 V
• Maximum Working Voltage: ±10 V (signal + common mode)
• Nonlinearity: ±0.005% of full scale range
• Power Consumption: 15 mA maximum
• Operating Temperature: 0 to 50 °C
• Storage Temperature: -55 to 150 °C
• Humidity: 5% to 90% non-condensing
– Key Features
• Open-thermocouple detection with indicator LEDs
• Per-channel cold-junction compensation
• Auto-zeroing for offset voltage removal
• Onboard voltage reference for external calibration
• 96-pin male DIN C front-panel connector
• 50-pin male ribbon cable rear-panel connector
– Compatibility & Integration
The SCXI-1112 operates within SCXI chassis (SCXI-1000 series compatible) and interfaces with National Instruments E Series MIO devices and SCXI-1200 modules via NI-DAQmx driver software. LabVIEW, LabWindows/CVI, ComponentWorks, and VirtualBench environments are supported.
