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FX3U “Modbus RTU” DELTA VFD-M Tutorial

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Hello everyone, today continues to write a tutorial for you to practice connecting PLCs with inverters via Modbus communication standard

Today I will use an extremely famous and popular PLC in the world, Mitsubishi FX3U combined with the FX3U-485ADP-MB Module.

Connection Diagram FX3U & VFD-M

DELTA VFD-M Inverter Configuration

To be able to switch the inverter to Modbus control mode, we need to set the following parameters:

+ Pr00:03” – Setting Frequency via RS485

+ Pr01:04” – Motor Control Run via RS485

+ Pr88:01” – Modbus Slave Station #1

+ Pr89:01” – Baud Rate 9600bps

+ Pr92:04” – Modbus RTU ( 8, 1, E )

+ Pr157:01” – Modbus-RTU Selection

Modbus Address Register

Addresses to receive control commands from the PLC

+ Use address 2000H for Start/Stop control

  • Run Forward (FWD): = 0000.0000.0001.0010 (Bin) = 12 (Hexa)
  • Run Reverse (REV): = 0000.0000.0010.0010 (Bin) = 22 (Hexa)
  • Stop: = 0000.0000.0000.0001 = 1

+ Frequency Setting: 2001H

Data Monitor Register

In the dark project read 4 important parameters including:

  • 2103H: Output Frequency
  • 2104H: Output Current
  • 2105H: DC-BUS Voltage
  • 2106H: Output Voltage


FX3U PLC Programming

+ Configure communication parameters in PLC (I use CH2 of FX3U)

+ Distributing Read and Write

+ Frequency Setting and Motor Control

+ Read Data Reponse

Detailed Instruction Video


As you can see, FX3U has built-in communication commands that can be easily configured and save programmer time. Here are the references

>>> Download VFD-M Manual PDF (Password Extract:

>>> Download FX3U Modbus Communication Manual PDF

>>> Download GX-Works2 for FX3U Programming

If you have any questions, please comment below the article, will answer you.

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