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DELTA VFD-M “Modbus RTU” via Modbus Poll

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Hello everyone! In many previous posts, has guided you to use different HMI/PLC to control Delta VFD-M inverter using Modbus-RTU RS485 communication standard. Today I would like to continue to guide you to use a PC to control the inverter directly.

To be able to do this we need the software “Modbus Poll” and “USB to RS485 Cable”

Wiring Diagram

The RS485 communication port of the VFD-M is an RJ-11 port (you can get a desk phone jack)

DELTA VFD-M Communication Setting

In addition to the basic parameters set by the motor (Frequency, Current, Voltage). We set the communication parameters as follows:

  • Pr00 = 03 (Frequency control via RS485)
  • Pr01 = 04 (Motor Control via RS485)
  • Pr88 = 01 (Slave No.1)
  • Pr89 = 01 (9600bps)
  • Pr92 = 04 (8, 1, Even)
  • Pr 157 = 01 (Modbus-RTU Selection)
Register for Control

>>> Motor Control Address = 2000 (Hex)

  • Run Forward = 0000.0000.0001.0010 (Bin) = 18 (dec)
  • Run Reverse = 0000.0000.0010.0010 (Bin) = 34 (dec)
  • Stop Run = 0000.0000.0000.0001 = 1

>>> Set Frequency Address = 2001 (Hex)

Register for Monitoring

In the dark project read 4 important parameters including:

+ 2103 (Hex): Output Frequency

+ 2104 (Hex): Output Current

+ 2105 (Hex): DC-BUS Voltage

+ 2106 (Hex): Output Voltage

“Modbus Poll” Software Programming

+ Motor Control Command

+ Frequency Setting

+ Data Monitoring

Detailed Instruction Video


Software & Document

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

>>> Download Modbus Poll Software

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Thanks and Best Regards!

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