The National Instruments FP-TC-120 is an 8-channel thermocouple input module for FieldPoint and Compact FieldPoint distributed I/O systems. It acquires temperature measurements across eight differential channels with support for J, K, R, S, T, N, E, and B thermocouple types, as well as millivolt signals. The module delivers 16-bit delta-sigma ADC resolution with built-in NIST-175 linearization and cold-junction compensation. Measurement ranges span 0 to 2,048 K (–270 to 1,770 °C, –454 to 3,218 °F) with accuracy typically within ±0.05 °C of the NIST standard. Hot-swappable design enables installation on powered systems without interruption.
Technical Specifications
Input Channels & Types
• 8 differential input channels
• Thermocouple types: J, K, R, S, T, N, E, B
• Millivolt signal support: ±25 mV, ±50 mV, ±100 mV, –20 to 80 mV ranges
• 16-bit delta-sigma ADC
• Input bandwidth: 3 Hz
• Input current: 35 nA typical, 140 nA maximum
• Input noise: ±1 LSB peak-to-peak
Measurement Performance
• Temperature range: 0 to 2,048 K (–270 to 1,770 °C, –454 to 3,218 °F)
• Accuracy: ±0.05 °C typical (0.03 °F)
• Cold-junction compensation: Built-in thermistor, ±0.15 °C typical (maximum 0.3 °C)
• NIST-175 linearization per ITS-90 International Temperature Scale
• Open thermocouple detection with red LED indicator
Protection & Isolation
• Overvoltage protection: ±40 V
• Transient overvoltage protection: 2,300 Vrms (inter-module bus to I/O channels)
• Bank isolation: Optical, 2,300 Vrms breakdown voltage
• Isolation voltage rating: 250 Vrms
• Common-mode voltage protection: 250 Vrms
• 50 Hz and 60 Hz filtering
Physical & Power
• Hot-swappable operation on powered terminal base or backplane
• Power consumption: Approximately 350 mW
• Compatible with FP-TB-3 isothermal terminal base or cFP-CB-3 isothermal connector block
– Key Features
• Eight independent thermocouple input channels
• Multiple thermocouple type support with automatic linearization
• Built-in cold-junction compensation for accurate temperature measurement
• Optical isolation for robust noise rejection in harsh industrial environments
• Hot-plug capability for system flexibility
– Typical Applications
• Industrial process monitoring and control
• Temperature data acquisition in distributed systems
• Multi-point thermal sensing in manufacturing environments
• Harsh-environment monitoring requiring isolation and protection
– Compatibility & Integration
The FP-TC-120 integrates with National Instruments FieldPoint and Compact FieldPoint distributed I/O systems. Optimal performance requires the FP-TB-3 isothermal terminal base or cFP-CB-3 isothermal connector block for cold-junction compensation accuracy.
