National Instruments 777318-120 Temperature Input Module

Often called the cFP-TC-120, the National Instruments 777318-120 is a sophisticated temperature input module made specifically for Compact FieldPoint systems. With its eight differential input channels, this module can detect temperature directly from a variety of common thermocouple types, such as J, K, T, N, R, S, E, and B. Accurate and dependable temperature monitoring is ensured by each channel's ability to identify open thermocouples. The module provides instant visual feedback when it detects an open thermocouple by lighting the matching red LED and reporting an error for that channel.

Because of its plug-and-play (HotPnP) functionality, the 777318-120 is simple to set up and incorporate into current systems. To provide excellent measurement accuracy, its integrated microcontroller linearizes and adjusts thermocouple data in accordance with NIST-90 standards. The module also makes the setup process easier for users by providing self-diagnostics and automatic scaling to engineering units.

Each input channel on the 777318-120 has a bias resistor to an isolated ground reference on the negative terminal (IN–) and a pull-up resistor on the positive terminal (IN+) for detecting open thermocouples. The FieldPoint system's common ground reference for every channel is kept apart from other modules to offer strong electrical isolation and security.

The module has built-in filtering to reduce noise from 50 and 60 Hz power lines, so even in harsh industrial applications, measurements will remain stable and precise. It provides accurate temperature readings over four voltage settings (±25, ±50, ±100, and –20 to 80 mV) with 16-bit resolution data sampling. In addition, the 777318-120 has a 250 Vrms isolation voltage rating and 2,300 Vrms transient overvoltage protection between the inter-module communication bus and the I/O channels, which improves its robustness and safety.

The 777318-120 is made for harsh conditions and can operate in a broad temperature range of -40 to 70 °C. The operational condition of the module is shown by the two green status LEDs on it, POWER and READY. The POWER LED illuminates upon proper installation and powering of the cFP-TC-120. The network module enters normal operation mode when the READY LED illuminates, signifying successful transmission and receipt of initial configuration data.