Product Overview

The Yokogawa F3LC51-2N is a UT Link Module designed for the FA-M3 PLC system. It enables simple and direct communication between a PLC and external intelligent devices such as temperature controllers and field instruments.

Unlike standard PC link or Modbus modules, the UT Link module is optimized for automatic data exchange without requiring dedicated communication programming, making system integration significantly easier.

It supports RS-422A / RS-485 communication, enabling long-distance and multi-device industrial networking.

Technical Specifications

Function and Working Principle

The F3LC51-2N acts as a communication and data refresh interface module between the FA-M3 PLC and external field devices.

Working Principle

1. External devices (e.g., temperature controllers) continuously exchange data with the module
2. The module automatically refreshes and maps device data into PLC registers
3. The PLC reads/writes data directly without communication programming
4. Data exchange can also occur based on events or triggers

PLCFA−M3↔External Devices  (UT Link)PLC_{FA-M3} \leftrightarrow External\,Devices \;(UT\,Link)PLCFA−M3​↔ExternalDevices(UTLink)

Key Functions

• Enables direct communication with UT-compatible field devices
• Automatic continuous data refresh (no communication programming required)
• Supports event-based data exchange
• Allows access to external device registers from PLC memory
• Connects up to 32 external devices
• Supports long-distance industrial communication (up to 1200 m)
• Reduces engineering complexity in system integration

System Role

The module functions as an industrial device integration gateway:

FA-M3 PLC → F3LC51-2N → Temperature controllers / field instruments

It is commonly used for:

• Temperature control systems
• Process instrumentation networks
• Simple distributed control loops
• Industrial monitoring systems
• Multi-device sensor integration

Industrial Applications

• Chemical process plants
• Petrochemical facilities
• Power generation systems
• Furnace and thermal control systems
• Food processing industries
• Pharmaceutical manufacturing
• HVAC and building automation
• Water treatment systems

Installation Guidelines

• Install in FA-M3 rack system only
• Use shielded twisted-pair RS-422/RS-485 cables
• Configure 2-wire or 4-wire mode correctly
• Enable termination resistors at network ends
• Maintain maximum cable distance of 1200 m
• Ensure correct device addressing for up to 32 units
• Avoid high electromagnetic noise areas

Compatible Systems

• Yokogawa FA-M3 PLC CPUs
• UT-compatible temperature controllers
• Industrial field instruments
• Distributed process control systems
• SCADA monitoring platforms

Key Advantages

• No communication programming required
• Automatic real-time data refresh
• Supports up to 32 connected devices
• Long-distance communication (1200 m)
• Flexible RS-422/RS-485 interface
• High reliability in industrial environments
• Simplified integration with field instruments

Technical FAQs

Q1: What is the main function of the F3LC51-2N?
It enables automatic communication between FA-M3 PLCs and external UT-compatible devices.

Q2: Does it require communication programming?
No, data exchange is handled automatically via register access.

Q3: How many devices can it support?
Up to 32 external devices.

Q4: What protocol does it use?
It uses Yokogawa’s proprietary UT Link protocol.

Conclusion

The Yokogawa F3LC51-2N UT Link Module is a specialized industrial communication interface that simplifies integration between FA-M3 PLC systems and external field devices. With automatic data refresh, long-distance capability, and support for multiple devices, it is ideal for efficient and low-complexity process control applications.