Product Overview

The Yokogawa NFLR121-S50 operates as a high-reliability serial communication interface for the STARDOM Field Control Node (FCN) system. Equipped with two independent RS-422/RS-485 ports, this module enables seamless integration between the primary controller and a vast array of subsystem devices, including power meters, motor drives, and specialized analytical instruments. It excels in large-scale industrial deployments where long-distance data acquisition—up to 1,200 meters—is mandatory for maintaining operational oversight. By supporting both half-duplex and full-duplex modes, the NFLR121-S50 ensures flexible topology configurations for multipoint communication networks. This module stabilizes the data flow across the plant floor, protecting the integrity of control signals from electromagnetic interference and ensuring that critical process variables reach the CPU with absolute precision.

Technical Configuration

The NFLR121-S50 follows the standard Yokogawa coding structure, which defines the communication protocol and hardware safety ratings.

Model Suffix Analysis

NFLR121: Basic Model Code for the RS-422/RS-485 Serial Communication Module designed for the FCN architecture.

-S: Designates the Standard Type module. This indicates the unit supports universal asynchronous communication protocols used across most industrial serial devices.

5: Identifies the protection level. This "Basic" code confirms the module is intended for installation in non-hazardous areas where no specialized explosion protection (Ex) is required.

0: Represents the "Basic Type" configuration without specialized functional additions, ensuring straightforward plug-and-play compatibility with standard FCN base units.

Technical Specifications

Installation Guide

Proper physical termination and electrical grounding are essential for high-speed serial reliability over long distances.

Wiring and Termination

Connect field devices using the M4 clamped terminal blocks. When operating in RS-485 multipoint mode, ensure you install a termination resistor (typically 120 ohms) at the farthest physical end of the cable run to prevent signal reflection. Maintain tight connections on the terminal block to avoid intermittent communication errors caused by vibration.

Cable Selection and Grounding

Use shielded twisted pair (STP) cabling for all RS-422/485 runs. Connect the cable shield to the functional ground (FG) at a single point only—usually at the NFLR121-S50 module end—to prevent ground loops. Ensure the total cable length does not exceed 1,200 meters to stay within the electrical signal timing requirements of the RS-485 standard.

Port Configuration

The module supports full-duplex (4-wire) and half-duplex (2-wire) configurations via software settings. Verify that your field device wiring matches the software-selected mode; an incorrect mode selection will lead to transmit/receive collisions and data timeouts.

Engineering Advantages

The NFLR121-S50 provides a ruggedized communication layer that shields the FCN controller from the electrical noise generated by industrial heavy machinery. Its dual-port design allows for redundant wiring paths or the separation of two distinct device networks on a single module, effectively doubling the I/O density. The use of M4 screw terminals ensures a "gas-tight" connection that resists the oxidation and loosening common in corrosive chemical environments. Furthermore, its high-speed baud rate capability (up to 115.2 kbps) minimizes communication latency, making it suitable for real-time monitoring of power systems where fast response times are critical.

Shipping and Delivery

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

Carrier Options: Worldwide shipping by DHL, FEDEX, or UPS.

Product Status: Brand New, Original Factory Sealed Pack, Large Stock Available.

Technical FAQs

Q1: Can Port 1 be used for RS-422 while Port 2 is used for RS-485?

A1: Yes. The NFLR121-S50 features two independent ports. You can configure each port with different communication parameters and electrical standards (RS-422 or RS-485) within the STARDOM configuration software.

Q2: Does this module support the Modbus RTU protocol?

A2: Yes. When paired with the appropriate software licenses on the FCN CPU, the NFLR121-S50 serves as the physical layer for Modbus RTU Master or Slave communications.

Q3: Is it possible to hot-swap the NFLR121-S50?

A3: The FCN hardware supports online module replacement; however, you must ensure that the communication tasks are properly managed in the logic to prevent system alarms during the brief disconnection.

Q4: What is the maximum number of devices I can connect to a single RS-485 port?

A4: While the RS-485 standard technically supports 32 unit loads, the actual number depends on the receiver impedance of your field devices. For optimal performance over 1,000+ meters, we recommend keeping the device count per port within manageable limits or using RS-485 repeaters.