Product Overview

The NFAR181-S00 S2 (NFAR181) is a high-density RTD input module designed for the Yokogawa STARDOM FCN-RTU autonomous controller series. This module provides 12 isolated channels for interfacing with various Resistance Temperature Detectors (RTD), including Pt100 and JPt100 types. Engineered for precision temperature monitoring in industrial processes such as furnace control, cryogenic storage, and HVAC systems, the NFAR181 ensures signal accuracy within 土0.03% of the full scale. Each channel is individually isolated to prevent noise propagation and ground loop interference, which is critical for maintaining stable measurement data in environments with heavy electrical machinery. By integrating these high-performance inputs directly into the STARDOM architecture, the module enables rapid data refresh cycles and high-reliability temperature compensation, significantly reducing the risk of process deviation and system downtime.

Technical Configuration

The NFAR181-S00 is built on a robust hardware platform optimized for long-term stability:

• 12-Channel Isolation: Every input channel is electrically isolated from both the system logic and adjacent channels, featuring a withstanding voltage of 1500 V AC.

• Measurement Precision: The module utilizes a 1 mA measurement current to determine resistance, minimizing self-heating errors while maintaining a high signal-to-noise ratio.

• Burn-out Detection: All channels can be configured for burn-out detection (UP/DOWN) within 60 seconds, providing immediate notification to the control logic in the event of sensor failure.

• Data Integrity: With a maximum temperature drift of $\pm 30$ ppm/Celsius and a 1-second data refresh cycle, the module provides consistent and repeatable measurements even under varying ambient conditions.

Technical Specifications

Technical FAQs

Which RTD standards are supported by the NFAR181?

The module supports multiple international standards, including JIS C 1604:1997/1989 and IEC 60751:1995/1986. This ensures compatibility with both modern and legacy Pt100 and JPt100 sensors.

What is the maximum allowable wiring resistance for each channel?

To maintain rated accuracy, the wiring resistance must be 40 Ohm or less per wire. It is critical that each of the three wires used in the 3-wire RTD configuration has equal resistance to effectively cancel out lead wire errors.

Can this module be used in hazardous locations?

The "S00" suffix indicates this is a standard version with no explosion protection. For applications in classified areas, it must be installed within a certified explosion-proof housing or used in conjunction with intrinsic safety barriers.

Engineering & Installation Guide

• Wiring Uniformity: Use 3-wire RTD configurations to compensate for lead wire resistance. Ensure all three wires are of the same length and gauge. Uneven resistance between lead wires will result in a measurement offset that cannot be corrected by the module's internal logic.

• Grounding and Shielding: Use twisted, shielded pairs for all RTD field wiring. The shield should be grounded at the controller side to a dedicated instrument ground. Avoid routing these low-level signal cables parallel to high-current AC power cables to prevent inductive noise coupling.

• Thermal Considerations: The module is rated for operation up to 70 deg C. When mounting in a STARDOM node, ensure that the pressure clamp terminals are securely tightened to minimize contact resistance, which can be misinterpreted as temperature changes.

• Mechanical Installation: The module dimensions are 32.8 mm in width and 130 mm in height. When inserting the module into the FCN-RTU backplane, confirm the module is fully seated before tightening the mounting screws to 0.5 Nm. Use the provided pressure clamp terminals for secure field connections.