Product Overview

The Yokogawa NFAR181-S50 stands as a high-precision thermal monitoring solution for the STARDOM Field Control Node (FCN) system. This module features 12 isolated channels specifically designed to interface with Pt100 RTD sensors, providing critical temperature data from the most demanding industrial environments. In applications involving large-scale rotating machinery—such as gas turbines and high-pressure compressors—this module monitors bearing temperatures and stator windings with laboratory-grade accuracy. By utilizing a 3-wire configuration, the NFAR181-S50 effectively cancels out lead-wire resistance, ensuring that thermal fluctuations are captured with a resolution of ±0.15°C. This high level of precision allows operators to detect early signs of mechanical friction or cooling system inefficiencies, preventing catastrophic equipment failure and optimizing maintenance intervals.

Technical Configuration

The NFAR181-S50 utilizes Yokogawa’s modular suffix logic to define its hardware capabilities and environmental suitability.

Model Suffix Breakdown

NFAR181: Basic Model Code identifying the 12-channel isolated RTD input module for the FCN platform.

-S: Designates the Standard Type, optimized for universal process automation and standard high-speed data acquisition tasks.

5: Indicates the protection and certification level. This "Basic" variant serves applications in non-hazardous locations where explosion protection is not required.

0: Represents the "Standard" functional configuration, ensuring seamless plug-and-play integration with the STARDOM backplane without specialized firmware modifications.

Technical Specifications

Installation Guide

Correct engineering practices during installation safeguard the integrity of temperature signals and extend the life of the module.

Wiring and Lead Resistance

Always use a 3-wire connection for each Pt100 sensor. Ensure that all three wires have identical resistance values to allow the module's internal circuitry to successfully compensate for lead length. For high-interference areas, utilize shielded twisted-pair cables and ground the shield at the module end only to eliminate potential ground loops.

Terminal Connection

The NFAR181-S50 supports pressure clamp terminals or MIL connector cables. When using pressure clamps, verify that the wire insulation does not enter the terminal cage, as this creates high-impedance "soft" connections. Maintain a minimum cable bending radius of 50mm to prevent internal conductor fatigue.

Burn-out Configuration

The system supports configurable burn-out detection for every channel. Engineers should set the detection logic within the software to "Up-scale" or "Down-scale" based on the specific safety protocol of the process. Note that the detection time is approximately 60 seconds.

Engineering Advantages

The NFAR181-S50 thrives in extreme environments characterized by high electromagnetic noise and rapid thermal cycling. Its 1500V AC isolation provides a formidable barrier, protecting the central CPU from field-side electrical surges. Unlike standard PLC inputs, this module features a highly stable measurement current of 1mA, which minimizes the self-heating effect of the RTD element, thereby preserving the accuracy of the reading. Its rugged Japan-made construction ensures long-term reliability in corrosive or high-vibration settings, making it the preferred choice for Turbine Supervisory Instrumentation (TSI) and critical process control loops.

Shipping and Delivery

Delivery Time: 3-5 business days upon payment finish.

Carrier: Reliable delivery by DHL, FEDEX, or UPS.

Status: Brand New, Original Factory Sealed, Large Inventory.

Technical FAQs

Q1: Can I connect a 2-wire RTD to the NFAR181-S50?

A1: While the module is designed for 3-wire inputs, you can use a 2-wire RTD by shorting the B and b terminals at the module. However, this will negate the lead-wire compensation and reduce overall measurement accuracy.

Q2: How does the isolation benefit my system?

A2: Each of the 12 channels is isolated from the system bus and from other channels. This prevents a fault on one sensor from propagating to other channels or damaging the FCN controller's internal electronics.

Q3: Is the module hot-swappable?

A3: Yes, the STARDOM FCN architecture supports the removal and insertion of modules while the system is powered. However, ensure the application logic is configured to handle the temporary signal loss during the swap.

Q4: Does this module support Pt1000 sensors?

A4: No. The NFAR181-S50 is specifically calibrated for Pt100 (ITS-90) standards. Connecting a Pt1000 sensor will result in incorrect temperature data.