Product Overview
The National Instruments FP-TC-120 is a thermocouple input module for FieldPoint systems. It provides eight thermocouple input channels with cold junction compensation. The module is designed for distributed temperature measurement in industrial and laboratory applications where thermocouples are used to monitor processes, equipment, and test articles.
The FP-TC-120 is part of the NI FieldPoint platform, which places signal conditioning and I/O modules close to sensors and connects them through a network module. This distributed architecture reduces long cable runs and simplifies wiring in industrial installations, particularly when temperature points are spread across a machine or process area.
Thermocouple Measurement
The module supports common thermocouple types and provides cold junction compensation to account for the reference junction temperature at the connector. This is necessary for accurate thermocouple readings. Engineers should select the correct thermocouple type in software and verify the configuration before collecting data.
Thermocouple signals are low level, so input filtering and careful wiring are important. Shielded thermocouple cable, correct polarity, and separation from power conductors help maintain measurement stability. Where sensors are attached to motors or heaters, additional care in cable routing is required to reduce noise pickup.
Channel Isolation
The FP-TC-120 provides channel to channel and channel to backplane isolation, which helps prevent ground loops and protects the system from common mode voltages. Isolation is valuable in industrial installations where thermocouples may be attached to equipment at different ground potentials.
Engineers should still review the grounding arrangement across the sensors, module, and network module. Isolation reduces risk but does not replace good wiring practice. Documentation of sensor locations, thermocouple types, and channel assignments helps during commissioning and maintenance.
FieldPoint Integration
The FP-TC-120 installs in a FieldPoint backplane along with other I/O modules and a network module. The network module handles communication with the host or control system. Engineers should verify that the backplane and network module support the number and type of modules in the planned system.
Module positions and channel mapping should be documented during commissioning. Consistent labeling helps during maintenance and troubleshooting. The distributed design allows the I/O to be mounted near the process, which can reduce installation cost and improve signal quality.
Industrial Installation
FieldPoint hardware is designed for industrial installation. Modules should be mounted where the operating temperature range is respected and where the enclosure protects against moisture, dust, and contaminants. DIN rail mounting is common, and engineers should leave clearance for wiring and ventilation.
Proper grounding and shielding are important for reliable temperature measurement. Signal wiring should be separated from power conductors, and shields should be terminated according to the documentation. These practices reduce noise and improve long term reliability in industrial environments.
Typical Applications
Distributed industrial temperature monitoring
Process and furnace temperature measurement
Machine and equipment thermal monitoring
Environmental and facility data acquisition
Legacy FieldPoint system expansion
Test stands with multiple thermocouple points
The FP-TC-120 provides eight thermocouple input channels with cold junction compensation and isolation for FieldPoint systems. Its distributed architecture and industrial design make it suitable for temperature measurement applications where sensors are spread across a facility.
