I. Basic Information

Model: CFP-CB-3 (cFP-CB-3)

Manufacturer: National Instruments (NI)

Series: Compact FieldPoint (cFP)

Part Number: 778618-03

Status: Obsolete

Location: Specialized for high-precision thermocouple measurement, isothermal structure reduces terminal temperature difference

Core Application: Combined with cFP-TC-120 / TC-125 (16-channel thermocouple input)

II. Key Differences from CFP-CB-1 (Most Frequently Asked Questions) Table

Parameters: 

CFP-1 (General type) - 36-pin (common for all modules) 

CFP-3 (Isothermal thermocouple type) - 18-pin (only for thermocouple module) 

Structure: Standard plastic casing 

CJC accuracy: ±0.15~0.3 °C 

±0.05~0.1 °C (higher) 

Temperature gradient: Normal (with temperature difference between terminals) 

Extremely small (terminal isothermal, lower thermal error of thermocouple) 

Recommended modules: AI-100/102/111, AO, DI/DO 

Only cFP-TC-120 / TC-125 

Price: Lower 

Higher (high-precision thermocouple dedicated) 

One sentence: CB-1 general; CB-3 high-precision dedicated for thermocouples, isothermal + more accurate CJC.

III. Core Specifications (Electrical / Wiring)

Number of terminals: 18 screw terminals (compatible with 16 thermocouples + power / ground) 

CJC sensor: Built-in high-precision thermistor, cold junction compensation accuracy ±0.05~0.1 °C 

Isothermal design: Temperature is uniform in I/O terminal area, suppressing mV level error of thermocouple 

Rated voltage: 250 Vrms (isolated) 

Rated current: 

V/C power terminal: 4 A 

Signal terminal: 2 A 

Wiring specification: 16–26 AWG copper wire, stripped 6 mm, torque 0.5–0.6 N·m 

Protection: Short circuit / Overcurrent protection, LED diagnosis 

IV. Mechanics and Environment 

Size: 127 × 66 × 24 mm (same as cFP standard module) 

Weight: Approximately 110 g 

Installation: cFP-BP-4 / BP-8 backplate, hot-swappable 

Operating temperature: -40 °C ~ +70 °C 

Humidity: 10%–90% RH, no condensation 

Protection: IP20, double stress release rods + belt slot (anti-vibration) 

V. Compatibility and Recommended Combinations 

The only recommended module: cFP-TC-120 (16 thermocouples, J/K/T/E/R/S/B/N) 

Compatible backplates: cFP-BP-4, cFP-BP-8 

Not recommended for: AI-100/102/111, AO-200/210, DI/DO (terminal insufficient, not isothermal) 

VI. Retirement Replacement 

Original system: Direct replacement with the same model spare parts (high-precision thermocouple measurement is necessary) 

New system: 

Module: NI-9213 (C series, 16 thermocouples, ±0.05 °C CJC) 

Base: NI-9923 (Isothermal type, high-precision CJC)