Learn MELSEC-FX-EXTENSIONS with Real Code Examples

FX Extensions allow FX PLCs to handle complex control tasks beyond the base instruction set.

Supports communication protocols, high-speed counting, positioning, and arithmetic operations.

Used in factory automation, packaging, material handling, and small-scale industrial processes.

Integrates with Mitsubishi PLC software (GX Works2/3) and FX hardware modules.

Provides modular function blocks for reusability and structured PLC programming.

Enhanced timers and counters

PID control and positioning instructions

Analog I/O handling with scaling and conversion

Data handling instructions for arrays and registers

Communication instructions for device networking

Instruction - command executed by FX CPU

Function block - reusable code module for FX programs

High-speed counter - instruction for rapid pulse counting

Positioning instruction - used for servo/stepper motion

Communication instruction - allows FX to exchange data with devices

Main program and subroutines (ladder or structured text)

Function block definitions for repeated logic

I/O configuration and mapping files

Communication settings and device registers

Project workspace in GX Works with FX CPU configuration

Define program logic using base and extension instructions

Instantiate function blocks for modular tasks

Configure high-speed counters or positioning modules

Set up communication parameters for networked devices

Test and debug program in GX Works simulator or on PLC

Beginner: basic extension instructions like timers and counters

Intermediate: using function blocks for repetitive logic

Advanced: high-speed counting and analog I/O scaling

Expert: networked device communication and multi-module integration

Architect: complete factory cell automation with FX PLC extensions

FX Extensions vs Base FX PLC: adds advanced instructions and communication

FX Extensions vs Q Series PLC: smaller scale but cost-effective for limited applications

FX Extensions vs Other PLCs (Siemens, Omron): Mitsubishi-specific, optimized for FX hardware

FX Extensions vs PC-based control: real-time PLC execution vs non-deterministic PC control

FX Extensions vs MELSEC iQ-F: iQ-F is newer, FX Extensions bring advanced functionality to legacy FX

2000 - Initial FX Extensions introduced for FX PLCs

2005 - High-speed counter and analog instructions added

2010 - PID and positioning function blocks integrated

2015 - Communication protocol support expanded

2018 - Function block libraries for modular programming released

2020 - Ethernet and Modbus TCP support updated

2023 - GX Works3 compatibility improvements

2025 - Current version with full extension support for FX CPU models

Instruction - command executed by FX CPU

Function block - reusable code module

High-speed counter - counts pulses quickly

PID instruction - proportional-integral-derivative control

Communication instruction - manages data exchange with external devices