F3LC31-2F | Yokogawa | Modbus RTU Communication Interface Module

Product Overview

The F3LC31-2F Modbus interface module from Yokogawa is a dedicated communication unit developed for the FA-M3 PLC platform. It provides stable serial data exchange between FA-M3 controllers and Modbus-compatible field equipment, including inverters, smart instruments, and third-party controllers.

Designed for continuous industrial operation, this module focuses on communication reliability rather than signal processing, making it suitable for distributed control and supervisory systems requiring deterministic Modbus RTU connectivity.

Manufacturer Information

Brand: Yokogawa Electric Corporation Country of Origin: Japan Product Family: FA-M3 PLC System Module Category: Serial Communication Interface

Core Functions

The F3LC31-2F operates as a Modbus RTU master or slave interface within FA-M3 PLC racks. It handles protocol framing, timing control, and electrical isolation to ensure consistent data transmission over RS-based serial networks.

The module does not perform analog or digital I/O processing and must be used in conjunction with FA-M3 CPU and I/O modules.

Technical Specifications

Model: F3LC31-2F Communication Protocol: Modbus RTU Physical Interface: Serial (RS-based) Number of Ports: Dual communication channels Electrical Isolation: Optical isolation between communication and system bus Compatible PLC System: Yokogawa FA-M3 Installation Type: PLC rack-mounted module Dimensions: 28.9 × 100 × 83.2 mm Weight: 0.3 kg

Key Technical Advantages

Dual serial ports allow flexible network architecture and multi-device integration. Optical isolation reduces susceptibility to electrical noise and ground potential differences. Compact module width minimizes control cabinet space requirements. Designed specifically for FA-M3 system backplane compatibility and power distribution. Stable Modbus timing control suitable for long-distance serial communication.

Typical Applications

FA-M3 PLC communication with Modbus-enabled variable frequency drives Data exchange with smart sensors, meters, and analyzers Integration of third-party controllers into Yokogawa PLC architectures Serial communication layers in distributed industrial control systems

Engineering Notes

The F3LC31-2F requires correct Modbus addressing, baud rate, and parity configuration within the FA-M3 CPU logic. Shielded cabling and proper grounding practices are strongly recommended to maintain communication stability, especially in high-noise environments.

FAQ

Q: Can the F3LC31-2F be used as a direct I/O module? A: No. This module is strictly a communication interface and does not support signal acquisition or output.

Q: Is the module compatible with Modbus TCP devices? A: No. The F3LC31-2F supports Modbus RTU only. Ethernet-based Modbus TCP requires a different communication module.

Q: Can both communication ports operate simultaneously? A: Yes. Dual ports allow flexible serial network configurations depending on the FA-M3 CPU program design.