NI cFP-TC-125 (Compact FieldPoint 8-channel isolated thermocouple input module)

cFP-TC-125 = cFP with 8 differential thermocouples, 250V isolation between channels, all types of thermocouples, 16-bit, discontinued, as an alternative to NI-9213.

I. Basic Information

Model: cFP-TC-125 (CFP-TC-125)

Manufacturer: National Instruments (NI)

Series: Compact FieldPoint (cFP)

Part Number: 777318-125

Status: Discontinued (Obsolete)

Location: High isolation industrial temperature acquisition, dedicated to thermocouples in strong interference environments

Core Difference: Compared to cFP-TC-120, it adds 250V common-mode isolation between channels, providing stronger anti-interference capability.

II. Core Specifications (Channels / Electrical)

Number of channels: 8 differential inputs (250V isolation between channels)

Thermocouple types: J/K/T/N/R/S/E/B (full coverage, NIST-90 linearization)

Measurement range:

K type: -200 °C ~ +1370 °C

S type: 0 ~ +1750 °C

Millivolt mode: -20 ~ +80 mV

Resolution: 16 bits (Δ-Σ)

Accuracy: ±0.1 °C (K type @25 °C, typical)

Cold junction compensation (CJC): Built-in high-precision sensor, automatic compensation

Isolation:

Channel - Backplane: 2300 Vrms

Channel - Channel: 250 Vrms (critical upgrade)

Filtering: 50/60 Hz noise suppression

Open-circuit detection: Supports thermocouple break-line diagnosis

Update rate: Approximately 10 Hz for all channels

III. Wiring and Base

Required base: CFP-CB-1 (36-pin wiring terminals)

Wiring per channel: IN+ / IN- (differential, directly connected to the positive and negative terminals of the thermocouple)

Compatible signals:

Standard thermocouples (J/K/T/N/R/S/E/B)

Low-level millivolt signals (-20 ~ +80 mV)

IV. Mechanical and Environmental

Size: 127 × 66 × 24 mm (standard CFP module)

Weight: Approximately 180 g

Installation: CFP-BP-4 / BP-8 backplane, hot-swappable (HotPnP)

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

Storage temperature: -55 °C ~ +85 °C

Humidity: 10%–90% RH, no condensation

V. Compatibility

Backplane: CFP-BP-4 (4 slots), CFP-BP-8 (8 slots)

Controller: CFP-180x / 2000 / 2100 series

Software: LabVIEW, FieldPoint Explorer, Modbus RTU/TCP

VI. End-of-Production Replacement (Direct Replacement)

Recommended replacement: NI-9213 (C series, 8-channel isolated thermocouple, 250V channel-to-channel isolation, 16 bits, direct replacement)

Base replacement: NI-9923 (C series universal terminal base)

VII. Typical Applications

Industrial furnaces, heat treatment equipment temperature monitoring (strong electrical interference environment)

Power, metallurgy, chemical high-temperature measurement points (high common-mode voltage scenarios)

Multi-channel high-precision temperature acquisition system

Old CFP system spare parts replacement (original TC-120 upgraded isolated version)